From 15a155ef0dd77e8e4ba55812ecbdac03cc684424 Mon Sep 17 00:00:00 2001 From: Paolo Carlini Date: Sat, 26 Sep 2009 21:30:59 +0000 Subject: [PATCH] lwg-active.html: Update to Revision R66. 2009-09-26 Paolo Carlini * doc/html/ext/lwg-active.html: Update to Revision R66. * doc/html/ext/lwg-closed.html: Likewise. * doc/html/ext/lwg-defects: Likewise. * doc/xml/manual/intro.xml: Update entry for DR 853. From-SVN: r152208 --- libstdc++-v3/ChangeLog | 8 + libstdc++-v3/doc/html/ext/lwg-active.html | 42889 ++++++++++++--------------- libstdc++-v3/doc/html/ext/lwg-closed.html | 27786 +++++++++++------ libstdc++-v3/doc/html/ext/lwg-defects.html | 5270 +++- libstdc++-v3/doc/xml/manual/intro.xml | 2 +- 5 files changed, 42290 insertions(+), 33665 deletions(-) diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index a2523a6..5ef5b3d 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,11 @@ +2009-09-26 Paolo Carlini + + * doc/html/ext/lwg-active.html: Update to Revision R66. + * doc/html/ext/lwg-closed.html: Likewise. + * doc/html/ext/lwg-defects: Likewise. + + * doc/xml/manual/intro.xml: Update entry for DR 853. + 2009-09-26 Gerald Pfeifer * doc/html/ext/lwg-closed.html: Adjust four instances of two URLs diff --git a/libstdc++-v3/doc/html/ext/lwg-active.html b/libstdc++-v3/doc/html/ext/lwg-active.html index 2413048..74e43ef 100644 --- a/libstdc++-v3/doc/html/ext/lwg-active.html +++ b/libstdc++-v3/doc/html/ext/lwg-active.html @@ -14,11 +14,11 @@ del {background-color:#FFA0A0} - + - + @@ -29,7 +29,7 @@ del {background-color:#FFA0A0}
Doc. no.N2894=09-0084N2940=09-0130
Date:2009-06-212009-08-02
Project:Howard Hinnant <howard.hinnant@gmail.com>
-

C++ Standard Library Active Issues List (Revision R65)

+

C++ Standard Library Active Issues List (Revision R66)

Reference ISO/IEC IS 14882:2003(E)

Also see:

@@ -47,9 +47,9 @@ del {background-color:#FFA0A0}

This document contains only library issues which are actively being - considered by the Library Working Group. That is, issues which have a + considered by the Library Working Group, i.e., issues which have a status of New, Open, - Ready, and Review. See + Ready, or Review. See Library Defect Reports List for issues considered defects and Library Closed Issues List for issues considered closed.

@@ -85,6 +85,58 @@ del {background-color:#FFA0A0}

Revision History

@@ -124,9 +176,9 @@ del {background-color:#FFA0A0}
  • 1111 issues total, up by 19.
  • Details:
    • @@ -141,26 +193,26 @@ del {background-color:#FFA0A0}
  • Details:
    • @@ -174,7 +226,7 @@ del {background-color:#FFA0A0}
  • 982 issues total, up by 44.
  • Details:
    • @@ -187,7 +239,7 @@ del {background-color:#FFA0A0}
  • 938 issues total, up by 20.
  • Details:
    • @@ -201,28 +253,28 @@ del {background-color:#FFA0A0}
  • Details:
    • @@ -236,7 +288,7 @@ del {background-color:#FFA0A0}
  • 878 issues total, up by 9.
  • Details:
    • @@ -249,9 +301,9 @@ del {background-color:#FFA0A0}
  • 869 issues total, up by 8.
  • Details:
      -
    • Added the following New issues: 862, 863, 864, 865, 866, 867, 868, 869.
      • +
    • Added the following New issues: 862, 863, 864, 865, 866, 867, 868, 869.
    • Changed the following issues from Pending NAD Editorial to NAD Editorial: 393, 557, 592, 754, 757.
      • -
    • Changed the following issues from Pending WP to Open: 644.
      • +
    • Changed the following issues from Pending WP to Open: 644.
    • Changed the following issues from WP to Ready: 387, 629.
    • Changed the following issues from Pending NAD Editorial to Review: 709.
    • @@ -267,21 +319,21 @@ del {background-color:#FFA0A0}
  • Details:
  • Details:
    • @@ -313,7 +365,7 @@ del {background-color:#FFA0A0}
  • Details:
  • Details:
  • Details:
    • @@ -380,14 +432,14 @@ del {background-color:#FFA0A0}
  • 754 issues total, up by 31.
  • Details:
  • Details:
    • @@ -418,15 +470,15 @@ del {background-color:#FFA0A0}
  • 708 issues total, up by 12.
  • Details:
      -
    • Added the following New issues: 697, 698, 699, 700, 701, 702, 703, 704, 705, 706, 707, 708.
      • +
    • Added the following New issues: 697, 698, 699, 700, 701, 702, 703, 704, 705, 706, 707, 708.
    • Changed the following issues from New to NAD: 583, 584, 662.
    • Changed the following issues from Open to NAD: 528.
    • Changed the following issues from New to NAD Editorial: 637, 647, 658, 690.
    • Changed the following issues from Open to NAD Editorial: 525.
    • Changed the following issues from Pending NAD Editorial to NAD Editorial: 553, 571, 591, 633, 636, 641, 642, 648, 649, 656.
      • -
    • Changed the following issues from New to Open: 579, 631, 680.
      • +
    • Changed the following issues from New to Open: 579, 631, 680.
    • Changed the following issues from Pending WP to Open: 258.
      • -
    • Changed the following issues from Ready to Pending WP: 644.
      • +
    • Changed the following issues from Ready to Pending WP: 644.
    • Changed the following issues from New to Ready: 577, 660.
    • Changed the following issues from Open to Ready: 488.
    • Changed the following issues from Open to Review: 518.
      • @@ -445,7 +497,7 @@ del {background-color:#FFA0A0}
    • 696 issues total, up by 20.
  • Details:
  • Details:
  • Details:
    • @@ -507,7 +559,7 @@ del {background-color:#FFA0A0}
  • 619 issues total, up by 10.
  • Details:
    • @@ -523,10 +575,10 @@ del {background-color:#FFA0A0}
  • Moved issues 520, 521, 530, 535, 537, 538, 540, 541 to WP.
  • Moved issues 504, 512, 516, 544, 549, 554, 555, 558 to NAD.
  • Moved issue 569 to Dup.
    • -
  • Moved issues 518, 523, 524, 542, 556, 557, 559, 597, 606 to Open.
    • +
  • Moved issues 518, 523, 524, 542, 556, 557, 559, 597, 606 to Open.
  • Moved issues 543, 545, 549, 549, 598 - 603, 605 to Ready.
  • Moved issues 531, 551, 604 to Review.
    • -
  • Added new issues 593, 594, 595, 596, 597, 598, 599, 600, 601, 602, 603, 604, 605, 606, 607, 608, 609.
    • +
  • Added new issues 593, 594, 595, 596, 597, 598, 599, 600, 601, 602, 603, 604, 605, 606, 607, 608, 609.
    • @@ -539,7 +591,7 @@ del {background-color:#FFA0A0}
  • 592 issues total, up by 5.
  • Details:
    • @@ -552,8 +604,8 @@ del {background-color:#FFA0A0}
  • 587 issues total, up by 13.
  • Details:
    • @@ -567,9 +619,9 @@ del {background-color:#FFA0A0}
  • 574 issues total, up by 8.
  • Details:
  • Details:
    • @@ -600,7 +652,7 @@ del {background-color:#FFA0A0}
  • 535 issues total.
  • Details:
    • @@ -608,7 +660,7 @@ del {background-color:#FFA0A0} 2005-10-14 post-Mont Tremblant mailing. Added new issues 526-528. Moved issues 280, 461, 464, 465, 467, 468, 474, 496 from Ready to WP as per the vote from Mont Tremblant. -Moved issues 247, 294, 342, 362, 369, 371, 376, 384, 475, 478, 495, 497 from Review to Ready. +Moved issues 247, 294, 342, 362, 369, 371, 376, 384, 475, 478, 495, 497 from Review to Ready. Moved issues 498, 504, 506, 509, 510, 511, 512, 513, 514 from New to Open. Moved issues 505, 507, 508, 519 from New to Ready. Moved issue 500 from New to NAD. @@ -617,11 +669,11 @@ Moved issue 504-522. -Added new issues 523-523 +Added new issues 523-523
  • R37: 2005-06 mid-term mailing. -Added new issues 498-503. +Added new issues 498-503.
  • R36: 2005-04 post-Lillehammer mailing. All issues in "ready" status except @@ -678,7 +730,7 @@ at the meeting.) Made progress on issues 226 involve wording.
  • R23: -Pre-Santa Cruz mailing. Added new issues 367-382. +Pre-Santa Cruz mailing. Added new issues 367-382. Moved issues in the TC to TC status.
  • R22: @@ -732,7 +784,7 @@ Changed status of issues to Ready. Closed issues -111 277 279 287 +111 277 279 287 289 293 302 313 314 as NAD. @@ -795,7 +847,7 @@ of issue 83, 86, 91, 92, -109. Added issues 190 to +109. Added issues 190 to 195. (99-0033/D1209, 14 Oct 99)
  • R9: @@ -811,10 +863,10 @@ in Dublin. (99-0016/N1193, 21 Apr 99) pre-Dublin updated: Added issues 130, 131, 132, 133, 134, 135, 136, 137, -138, 139 (31 Mar 99) +138, 139 (31 Mar 99)
  • R6: -pre-Dublin mailing. Added issues 127, 128, +pre-Dublin mailing. Added issues 127, 128, and 129. (99-0007/N1194, 22 Feb 99)
  • R5: @@ -824,7 +876,7 @@ for making list public. (30 Dec 98)
  • R4: post-Santa Cruz II updated: Issues 110, -111, 112, 113 added, several +111, 112, 113 added, several issues corrected. (22 Oct 98)
  • R3: @@ -879,6 +931,10 @@ format, NAD Concepts - The LWG has reached consensus that + the issue is NAD for now, but represents a real issue when the library is + done with language-supported concepts.

    +

    NAD Future - In addition to the regular status, the LWG believes that this issue should be revisited at the next revision of the standard.

    @@ -952,9 +1008,11 @@ format, 96. Vector<bool> is not a container -

    Section: 23.3.6 [vector] Status: Tentatively NAD Future - Submitter: AFNOR Opened: 1998-10-07 Last modified: 2009-05-25

    +

    Section: 23.3.6 [vector] Status: Open + Submitter: AFNOR Opened: 1998-10-07 Last modified: 2009-07-29

    +

    View other active issues in [vector].

    View all other issues in [vector].

    +

    View all issues with Open status.

    Discussion:

    vector<bool> is not a container as its reference and pointer types are not references and pointers.

    @@ -1078,217 +1136,48 @@ and agree with Alisdair's recommendations. Move to NAD Future for reconsideration of part (ii). - -

    Proposed resolution:

    -

    -We now have: -N2050 -and -N2160. -

    - - - - - - -
    -

    111. istreambuf_iterator::equal overspecified, inefficient

    -

    Section: 24.6.3.5 [istreambuf.iterator::equal] Status: Open - Submitter: Nathan Myers Opened: 1998-10-15 Last modified: 2009-03-13

    -

    View other active issues in [istreambuf.iterator::equal].

    -

    View all other issues in [istreambuf.iterator::equal].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    The member istreambuf_iterator<>::equal is specified to be -unnecessarily inefficient. While this does not affect the efficiency -of conforming implementations of iostreams, because they can -"reach into" the iterators and bypass this function, it does -affect users who use istreambuf_iterators.

    - -

    The inefficiency results from a too-scrupulous definition, which -requires a "true" result if neither iterator is at eof. In -practice these iterators can only usefully be compared with the -"eof" value, so the extra test implied provides no benefit, -but slows down users' code.

    - -

    The solution is to weaken the requirement on the function to return -true only if both iterators are at eof.

    - -

    [ -Summit: -]

    - - -
    -Reopened by Alisdair. -
    -

    [ -Post Summit Daniel adds: +2009-07-29 Alisdair reopens: ]

    -Recommend NAD. The proposed wording would violate the axioms of -concept requirement EqualityComparable axioms as part of concept InputIterator -and more specifically it would violate the explicit wording of -24.2.2 [input.iterators]/7: +This infamous issue was closed as NAD Future when concepts introduced +support for proxy iterators, so the only remaining requirement was to +provide a better type to support bitsets of dynamic length. I fear we +must re-open this issue until the post-concept form of iterators is +available, and hopefully will support the necessary proxy functionality +to allow us to close this issue as NAD.

    -
    -If two iterators a and b of the same type are equal, then either a -and b are both -dereferenceable or else neither is dereferenceable. -
    - -
    - - - -

    Proposed resolution:

    -

    Replace 24.6.3.5 [istreambuf.iterator::equal], -paragraph 1,

    - -
    -

    -1- Returns: true if and only if both iterators are at end-of-stream, or neither is at - end-of-stream, regardless of what streambuf object they use.

    -
    - -

    with

    - -
    -

    -1- Returns: true if and only if both iterators are at - end-of-stream, regardless of what streambuf object they use.

    -
    - - - -

    Rationale:

    -

    It is not clear that this is a genuine defect. Additionally, the -LWG was reluctant to make a change that would result in -operator== not being a equivalence relation. One consequence of -this change is that an algorithm that's passed the range [i, i) -would no longer treat it as an empty range.

    - - - - - -
    -

    128. Need open_mode() function for file stream, string streams, file buffers, and string  buffers

    -

    Section: 27.8 [string.streams], 27.9 [file.streams] Status: Open - Submitter: Angelika Langer Opened: 1999-02-22 Last modified: 2008-03-14

    -

    View all other issues in [string.streams].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    The following question came from Thorsten Herlemann:

    - -
    -

    You can set a mode when constructing or opening a file-stream or - filebuf, e.g. ios::in, ios::out, ios::binary, ... But how can I get - that mode later on, e.g. in my own operator << or operator - >> or when I want to check whether a file-stream or - file-buffer object passed as parameter is opened for input or output - or binary? Is there no possibility? Is this a design-error in the - standard C++ library?

    +

    +I recommend we spawn a separate issue (1184) requesting a dynamic length bitset +and pre-emptively file it as NAD Future. It is difficult to resolve #96 +when it effectively contains two separate sub-issues. +

    -

    It is indeed impossible to find out what a stream's or stream -buffer's open mode is, and without that knowledge you don't know -how certain operations behave. Just think of the append mode.

    - -

    Both streams and stream buffers should have a mode() function that returns the -current open mode setting.

    - -

    [ -post Bellevue: Alisdair requested to re-Open. -]

    - - -

    Proposed resolution:

    -

    For stream buffers, add a function to the base class as a non-virtual function -qualified as const to 27.6.2 [streambuf]:

    - -

        openmode mode() const;

    - -

        Returns the current open mode.

    - -

    With streams, I'm not sure what to suggest. In principle, the mode -could already be returned by ios_base, but the mode is only -initialized for file and string stream objects, unless I'm overlooking -anything. For this reason it should be added to the most derived -stream classes. Alternatively, it could be added to basic_ios -and would be default initialized in basic_ios<>::init().

    - - -

    Rationale:

    -

    This might be an interesting extension for some future, but it is -not a defect in the current standard. The Proposed Resolution is -retained for future reference.

    - - - - - -
    -

    138. Class ctype_byname<char> redundant and misleading

    -

    Section: 22.4.1.4 [locale.codecvt] Status: Open - Submitter: Angelika Langer Opened: 1999-03-18 Last modified: 2009-03-09

    -

    View other active issues in [locale.codecvt].

    -

    View all other issues in [locale.codecvt].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    Section 22.4.1.4 [locale.codecvt] specifies that -ctype_byname<char> must be a specialization of the ctype_byname -template.

    - -

    It is common practice in the standard that specializations of class templates are only -mentioned where the interface of the specialization deviates from the interface of the -template that it is a specialization of. Otherwise, the fact whether or not a required -instantiation is an actual instantiation or a specialization is left open as an -implementation detail.

    - -

    Clause 22.2.1.4 deviates from that practice and for that reason is misleading. The -fact, that ctype_byname<char> is specified as a specialization suggests that there -must be something "special" about it, but it has the exact same interface as the -ctype_byname template. Clause 22.2.1.4 does not have any explanatory value, is at best -redundant, at worst misleading - unless I am missing anything.

    - -

    Naturally, an implementation will most likely implement ctype_byname<char> as a -specialization, because the base class ctype<char> is a specialization with an -interface different from the ctype template, but that's an implementation detail and need -not be mentioned in the standard.

    - -

    [ -Summit: -]

    - - -
    -Reopened by Alisdair. -
    - +

    +We now have: +N2050 +and +N2160. +

    -

    Rationale:

    -

    The standard as written is mildly misleading, but the correct fix -is to deal with the underlying problem in the ctype_byname base class, -not in the specialization. See issue 228.

    149. Insert should return iterator to first element inserted

    -

    Section: 23.2.3 [sequence.reqmts] Status: Open - Submitter: Andrew Koenig Opened: 1999-06-28 Last modified: 2009-05-01

    -

    View other active issues in [sequence.reqmts].

    +

    Section: 23.2.3 [sequence.reqmts] Status: Ready + Submitter: Andrew Koenig Opened: 1999-06-28 Last modified: 2009-07-15

    View all other issues in [sequence.reqmts].

    -

    View all issues with Open status.

    +

    View all issues with Ready status.

    Discussion:

    Suppose that c and c1 are sequential containers and i is an iterator that refers to an element of c. Then I can insert a copy of @@ -1374,6 +1263,25 @@ Proposed wording provided.

    +

    [ +2009-07 Frankfurt +]

    + + +
    +

    +Q: why isn't this change also proposed for associative containers? +

    + +

    +A: The returned iterator wouldn't necessarily point to a contiguous range. +

    + +

    +Moved to Ready. +

    +
    +

    Proposed resolution:

    @@ -1456,50 +1364,13 @@ first element inserted into a, or p if il is empty.

    -p9 23.2.6.1 [container.concepts.free] change return type from -void to iterator: -

    - -
    concept RangeInsertionContainer<typename C, typename Iter> : InsertionContainer<C> {
-  requires InputIterator<Iter>;
-  void iterator insert(C&, const_iterator position, Iter first, Iter last);
-}
-
    - -

    -p9 23.2.6.2 [container.concepts.member] change return type from -void to iterator: -

    - -
    auto concept MemberRangeInsertionContainer<typename C, typename Iter> : MemberInsertionContainer<C> {
-  requires InputIterator<Iter>;
-  void iterator C::insert(const_iterator position, Iter first, Iter last);
-}
-
    - -

    -p8 23.2.6.3 [container.concepts.maps] change return type from -void to iterator, add return statement: -

    - -
    template <MemberRangeInsertionContainer C, InputIterator Iter>
-concept_map RangeInsertionContainer<C, Iter> {
-  void iterator insert(C& c, Container<C>::const_iterator i, Iter first, Iter last)
-  { return c.insert(i, first, last); }
-}
-
    - -

    p2 23.3.2 [deque] Update class definition, change return type from void to iterator:

    -
    requires AllocatableElement<Alloc, T, const T&> && MoveAssignable<T>
-  void iterator insert(const_iterator position, size_type n, const T& x);
-template <InputIterator Iter>
-  requires AllocatableElement<Alloc, T, Iter::reference> && MoveAssignable<T>
-  void iterator insert(const_iterator position, Iter first, Iter last);
-requires AllocatableElement<Alloc, T, const T&> && MoveAssignable<T>
+
    void iterator insert(const_iterator position, size_type n, const T& x);
+template <class InputIterator>
+  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
   void iterator insert(const_iterator position, initializer_list<T>);
 
    
 
@@ -1507,19 +1378,16 @@ requires AllocatableElement<Alloc, T, const T&> && MoveAssigna
 23.3.2.3 [deque.modifiers] change return type from void to iterator on following declarations:
 
    
 
-
    requires AllocatableElement<Alloc, T, const T&> && MoveAssignable<T>
-  void iterator insert(const_iterator position, size_type n, const T& x);
-template <InputIterator Iter>
-  requires AllocatableElement<Alloc, T, Iter::reference> && MoveAssignable<T>
-  void iterator insert(const_iterator position, Iter first, Iter last);
+
      void iterator insert(const_iterator position, size_type n, const T& x);
+template <class InputIterator>
+  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
 
    
 
 
    
 Add the following (missing) declaration
 
    
 
-
    requires AllocatableElement<Alloc, T, const T&> && MoveAssignable<T>
-  iterator insert(const_iterator position, initializer_list<T>);
+
    iterator insert(const_iterator position, initializer_list<T>);
 
    
 
 
    
@@ -1527,21 +1395,17 @@ Add the following (missing) declaration
 from void to iterator:
 
    
 
-
    requires AllocatableElement<Alloc, T, const T&>
-  void iterator insert_after(const_iterator position, initializer_list<T> il);
-requires AllocatableElement<Alloc, T, const T&>
-  void iterator insert_after(const_iterator position, size_type n, const T& x);
-template <InputIterator Iter>
-  requires AllocatableElement<Alloc, T, Iter::reference>
-  void iterator insert_after(const_iterator position, Iter first, Iter last);
+
    void iterator insert_after(const_iterator position, initializer_list<T> il);
+void iterator insert_after(const_iterator position, size_type n, const T& x);
+template <class InputIterator>
+  void iterator insert_after(const_iterator position, InputIterator first, InputIterator last);
 
    
 
 
    
 p8 23.3.3.4 [forwardlist.modifiers] change return type from void to iterator:
 
    
 
-
    requires AllocatableElement<Alloc, T, const T&>
-  void iterator insert_after(const_iterator position, size_type n, const T& x);
+
    void iterator insert_after(const_iterator position, size_type n, const T& x);
 
    
 
 
    
@@ -1556,9 +1420,8 @@ Returns: position.
 p10 23.3.3.4 [forwardlist.modifiers] change return type from void to iterator:
 
    
 
-
    template <InputIterator Iter>
-  requires AllocatableElement<Alloc, T, Iter::reference>
-  void iterator insert_after(const_iterator position, Iter first, Iter last);
+
    template <class InputIterator>
+  void iterator insert_after(const_iterator position, InputIterator first, InputIterator last);
 
    
 
 
    
@@ -1573,8 +1436,7 @@ Returns: position.
 p12 23.3.3.4 [forwardlist.modifiers] change return type from void to iterator on following declarations:
 
    
 
-
    requires AllocatableElement<Alloc, T, const T&>
-  void iterator insert_after(const_iterator position, initializer_list<T> il);
+
    void iterator insert_after(const_iterator position, initializer_list<T> il);
 
    
 
 
    
@@ -1585,36 +1447,29 @@ change return type from void to iterator on following declarat
 p2 23.3.4 [list] Update class definition, change return type from void to iterator:
 
    
 
-
    requires AllocatableElement<Alloc, T, const T&> && MoveAssignable<T>
-  void iterator insert(const_iterator position, size_type n, const T& x);
+
    void iterator insert(const_iterator position, size_type n, const T& x);
 
-template <InputIterator Iter>
-  requires AllocatableElement<Alloc, T, Iter::reference> && MoveAssignable<T>
-  void iterator insert(const_iterator position, Iter first, Iter last);
+template <class InputIterator>
+void iterator insert(const_iterator position, InputIterator first, InputIterator last);
 
-requires AllocatableElement<Alloc, T, const T&> && MoveAssignable<T>
-  void iterator insert(const_iterator position, initializer_list<T>);
+void iterator insert(const_iterator position, initializer_list<T>);
 
    
 
-
 
    
 23.3.4.3 [list.modifiers] change return type from void to iterator on following declarations:
 
    
 
-
    requires AllocatableElement<Alloc, T, const T&> && MoveAssignable<T>
-  void iterator insert(const_iterator position, size_type n, const T& x);
+
    void iterator insert(const_iterator position, size_type n, const T& x);
 
-template <InputIterator Iter>
-  requires AllocatableElement<Alloc, T, Iter::reference> && MoveAssignable<T>
-  void iterator insert(const_iterator position, Iter first, Iter last);
+template <class InputIterator>
+  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
 
    
 
 
    
 Add the following (missing) declaration
 
    
 
-
    requires AllocatableElement<Alloc, T, const T&> && MoveAssignable<T>
-  iterator insert(const_iterator position, initializer_list<T>);
+
    iterator insert(const_iterator position, initializer_list<T>);
 
    
 
 
    
@@ -1625,38 +1480,31 @@ p2 23.3.6 [vector]
 Update class definition, change return type from void to iterator:
 
    
 
-
    requires AllocatableElement<Alloc, T, T&&> && MoveAssignable<T>
-  void iterator insert(const_iterator position, T&& x);
+
    void iterator insert(const_iterator position, T&& x);
 
-requires AllocatableElement<Alloc, T, const T&> && MoveAssignable<T>
-  void iterator insert(const_iterator position, size_type n, const T& x);
+void iterator insert(const_iterator position, size_type n, const T& x);
 
-template <InputIterator Iter>
-  requires AllocatableElement<Alloc, T, Iter::reference> && MoveAssignable<T>
-  void iterator insert(const_iterator position, Iter first, Iter last);
+template <class InputIterator>
+  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
 
-requires AllocatableElement<Alloc, T, const T&> && MoveAssignable<T>
-  void iterator insert(const_iterator position, initializer_list<T>);
+void iterator insert(const_iterator position, initializer_list<T>);
 
    
 
 
    
 23.3.6.4 [vector.modifiers] change return type from void to iterator on following declarations:
 
    
 
-
    requires AllocatableElement<Alloc, T, const T&> && MoveAssignable<T>
-  void iterator insert(const_iterator position, size_type n, const T& x);
+
    void iterator insert(const_iterator position, size_type n, const T& x);
 
-template <InputIterator Iter>
-  requires AllocatableElement<Alloc, T, Iter::reference> && MoveAssignable<T>
-  void iterator insert(const_iterator position, Iter first, Iter last);
+template <class InputIterator>
+  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
 
    
 
 
    
 Add the following (missing) declaration
 
    
 
-
    requires AllocatableElement<Alloc, T, const T&> && MoveAssignable<T>
-  iterator insert(const_iterator position, initializer_list<T>);
+
    iterator insert(const_iterator position, initializer_list<T>);
 
    
 
 
@@ -1666,9 +1514,8 @@ p1 23.3.7 [vector.bool] Update class definition, change return type from voi
 
 
    void iterator insert (const_iterator position, size_type n, const bool& x);
 
-template <InputIterator Iter>
-  requires Convertible<Iter::reference, bool>
-  void iterator insert(const_iterator position, Iter first, Iter last);
+template <class InputIterator>
+  void iterator insert(const_iterator position, InputIterator first, InputIterator last);
 
   void iterator insert(const_iterator position, initializer_list<bool> il);
 
    
@@ -1753,1803 +1600,1059 @@ not a defect. It may be worth revisiting for the next standard.
    
 
 
 
    
-
    190. min() and max() functions should be std::binary_functions
    
-
    Section: 25.5.7 [alg.min.max] Status: Open
- Submitter: Mark Rintoul Opened: 1999-08-26  Last modified: 2008-03-14
    
-
    View other active issues in [alg.min.max].
    
-
    View all other issues in [alg.min.max].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    Both std::min and std::max are defined as template functions.  This
-is very different than the definition of std::plus (and similar
-structs) which are defined as function objects which inherit
-std::binary_function.
    
-
    
-        This lack of inheritance leaves std::min and std::max somewhat useless in standard library algorithms which require
-a function object that inherits std::binary_function.
    
-
-
    [
-post Bellevue:  Alisdair requested to re-Open.
-]
    
-
-
-
-
-
    Rationale:
    
-
    Although perhaps an unfortunate design decision, the omission is not a defect
-in the current standard.  A future standard may wish to consider additional
-function objects.
    
-
-
-
-
-
    
-
    219. find algorithm missing version that takes a binary predicate argument
    
-
    Section: 25.3.5 [alg.find] Status: Open
- Submitter: Pablo Halpern Opened: 2000-03-06  Last modified: 2009-03-09
    
-
    View all other issues in [alg.find].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    The find function always searches for a value using operator== to compare the
-value argument to each element in the input iterator range. This is inconsistent
-with other find-related functions such as find_end and find_first_of, which
-allow the caller to specify a binary predicate object to be used for determining
-equality. The fact that this can be accomplished using a combination of find_if
-and bind_1st or bind_2nd does not negate the desirability of a consistent,
-simple, alternative interface to find.
    
-
-
    [
-Summit:
-]
    
-
-
-
    
-Reopened by Alisdair.
-
    
-
-
-
-
    Proposed resolution:
    
-
    
-
    In section 25.3.5 [alg.find], add a second prototype for find
-(between the existing prototype and the prototype for find_if), as
-follows:
    
-
        template<class InputIterator, class T, class BinaryPredicate>
-      InputIterator find(InputIterator first, InputIterator last,
-                         const T& value, BinaryPredicate bin_pred);
    
-
    Change the description of the return from:
    
-
    
-  
    Returns: The first iterator i in the range [first, last) for which the following corresponding
-  conditions hold: *i == value, pred(*i) != false. Returns last if no such iterator is found.
    
-
    
-
     to:
    
-
    
-  
    Returns: The first iterator i in the range [first, last) for which the following 
-  corresponding condition holds: *i == value, bin_pred(*i,value) != false, pred(*)
-  != false. Return last if no such iterator is found.
    
-
    
-
    
-
-
-
    Rationale:
    
-
    This is request for a pure extension, so it is not a defect in the
-current standard.  As the submitter pointed out, "this can
-be accomplished using a combination of find_if and bind_1st or
-bind_2nd".
    
-
-
-
-
-
    
-
    255. Why do basic_streambuf<>::pbump() and gbump() take an int?
    
-
    Section: 27.6.2 [streambuf] Status: Open
- Submitter: Martin Sebor Opened: 2000-08-12  Last modified: 2007-01-15
    
-
    View all other issues in [streambuf].
    
+
    299. Incorrect return types for iterator dereference
    
+
    Section: 24.2.5 [bidirectional.iterators], 24.2.6 [random.access.iterators] Status: Open
+ Submitter: John Potter Opened: 2001-01-22  Last modified: 2009-07-28
    
+
    View all other issues in [bidirectional.iterators].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-The basic_streambuf members gbump() and pbump() are specified to take an
-int argument. This requirement prevents the functions from effectively
-manipulating buffers larger than std::numeric_limits<int>::max()
-characters. It also makes the common use case for these functions
-somewhat difficult as many compilers will issue a warning when an
-argument of type larger than int (such as ptrdiff_t on LLP64
-architectures) is passed to either of the function. Since it's often the
-result of the subtraction of two pointers that is passed to the
-functions, a cast is necessary to silence such warnings. Finally, the
-usage of a native type in the functions signatures is inconsistent with
-other member functions (such as sgetn() and sputn()) that manipulate the
-underlying character buffer. Those functions take a streamsize argument.
+In section 24.2.5 [bidirectional.iterators],
+Table 75 gives the return type of *r-- as convertible to T.  This is
+not consistent with Table 74 which gives the return type of *r++ as
+T&.  *r++ = t is valid while *r-- = t is invalid.
 
    
 
-
-
    Proposed resolution:
    
 
    
-Change the signatures of these functions in the synopsis of template
-class basic_streambuf (27.5.2) and in their descriptions (27.5.2.3.1, p4
-and 27.5.2.3.2, p4) to take a streamsize argument.
+In section 24.2.6 [random.access.iterators],
+Table 76 gives the return type of a[n] as convertible to T.  This is
+not consistent with the semantics of *(a + n) which returns T& by
+Table 74.  *(a + n) = t is valid while a[n] = t is invalid.
 
    
 
 
    
-Although this change has the potential of changing the ABI of the
-library, the change will affect only platforms where int is different
-than the definition of streamsize. However, since both functions are
-typically inline (they are on all known implementations), even on such
-platforms the change will not affect any user code unless it explicitly
-relies on the existing type of the functions (e.g., by taking their
-address). Such a possibility is IMO quite remote.
+Discussion from the Copenhagen meeting: the first part is
+uncontroversial.  The second part, operator[] for Random Access
+Iterators, requires more thought.  There are reasonable arguments on
+both sides.  Return by value from operator[] enables some potentially
+useful iterators, e.g. a random access "iota iterator" (a.k.a
+"counting iterator" or "int iterator").  There isn't any obvious way
+to do this with return-by-reference, since the reference would be to a
+temporary.  On the other hand, reverse_iterator takes an
+arbitrary Random Access Iterator as template argument, and its
+operator[] returns by reference.  If we decided that the return type
+in Table 76 was correct, we would have to change
+reverse_iterator.  This change would probably affect user
+code.
 
    
 
 
    
-Alternate Suggestion from Howard Hinnant, c++std-lib-7780:
+History: the contradiction between reverse_iterator and the
+Random Access Iterator requirements has been present from an early
+stage.  In both the STL proposal adopted by the committee
+(N0527==94-0140) and the STL technical report (HPL-95-11 (R.1), by
+Stepanov and Lee), the Random Access Iterator requirements say that
+operator[]'s return value is "convertible to T".  In N0527
+reverse_iterator's operator[] returns by value, but in HPL-95-11
+(R.1), and in the STL implementation that HP released to the public,
+reverse_iterator's operator[] returns by reference.  In 1995, the
+standard was amended to reflect the contents of HPL-95-11 (R.1).  The
+original intent for operator[] is unclear.
 
    
 
 
    
-This is something of a nit, but I'm wondering if streamoff wouldn't be a 
-better choice than streamsize.  The argument to pbump and gbump MUST be 
-signed.  But the standard has this to say about streamsize 
-(27.4.1/2/Footnote):
+In the long term it may be desirable to add more fine-grained 
+iterator requirements, so that access method and traversal strategy
+can be decoupled.  (See "Improved Iterator Categories and
+Requirements", N1297 = 01-0011, by Jeremy Siek.)  Any decisions
+about issue 299 should keep this possibility in mind.
 
    
 
-
    
-     [Footnote: streamsize is used in most places where ISO C would use
-     size_t.  Most of the uses of streamsize could use size_t, except for
-     the strstreambuf constructors, which require negative values. It
-     should probably be the signed type corresponding to size_t (which is
-     what Posix.2 calls ssize_t). --- end footnote]
-
    
+
    Further discussion: I propose a compromise between John Potter's
+resolution, which requires T& as the return type of
+a[n], and the current wording, which requires convertible to
+T. The compromise is to keep the convertible to T
+for the return type of the expression a[n], but to also add
+a[n] = t as a valid expression. This compromise "saves" the
+common case uses of random access iterators, while at the same time
+allowing iterators such as counting iterator and caching file
+iterators to remain random access iterators (iterators where the
+lifetime of the object returned by operator*() is tied to the
+lifetime of the iterator).
+
    
 
 
    
-This seems a little weak for the argument to pbump and gbump.  Should we 
-ever really get rid of strstream, this footnote might go with it, along 
-with the reason to make streamsize signed.
+Note that the compromise resolution necessitates a change to
+reverse_iterator. It would need to use a proxy to support
+a[n] = t.
 
    
 
+
    
+Note also there is one kind of mutable random access iterator that
+will no longer meet the new requirements. Currently, iterators that
+return an r-value from operator[] meet the requirements for a
+mutable random access iterartor, even though the expression a[n] =
+t will only modify a temporary that goes away. With this proposed
+resolution, a[n] = t will be required to have the same
+operational semantics as *(a + n) = t.
+
    
 
-
    Rationale:
    
-
    The LWG believes this change is too big for now.  We may wish to
-reconsider this for a future revision of the standard.  One
-possibility is overloading pbump, rather than changing the
-signature.
    
 
    [
-[2006-05-04: Reopened at the request of Chris (Krzysztof ?elechowski)]
+2009-07-28 Reopened by Alisdair.  No longer solved by concepts.
 ]
    
 
 
 
 
-
-
    
-
    290. Requirements to for_each and its function object
    
-
    Section: 25.3.4 [alg.foreach] Status: Open
- Submitter: Angelika Langer Opened: 2001-01-03  Last modified: 2006-12-27
    
-
    View other active issues in [alg.foreach].
    
-
    View all other issues in [alg.foreach].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    The specification of the for_each algorithm does not have a
-"Requires" section, which means that there are no
-restrictions imposed on the function object whatsoever. In essence it
-means that I can provide any function object with arbitrary side
-effects and I can still expect a predictable result. In particular I
-can expect that the function object is applied exactly last - first
-times, which is promised in the "Complexity" section.
-
    
-
-
    I don't see how any implementation can give such a guarantee
-without imposing requirements on the function object.
-
    
-
-
    Just as an example: consider a function object that removes
-elements from the input sequence.  In that case, what does the
-complexity guarantee (applies f exactly last - first times) mean?
-
    
-
-
    One can argue that this is obviously a nonsensical application and
-a theoretical case, which unfortunately it isn't.  I have seen
-programmers shooting themselves in the foot this way, and they did not
-understand that there are restrictions even if the description of the
-algorithm does not say so.
-
    
-
    [Lillehammer: This is more general than for_each.  We don't want
-  the function object in transform invalidiating iterators
-  either. There should be a note somewhere in clause 17 (17, not 25)
-  saying that user code operating on a range may not invalidate
-  iterators unless otherwise specified.  Bill will provide wording.]
    
-
-
-
 
    Proposed resolution:
    
 
-
-
-
-
-
-
    
-
    309. Does sentry catch exceptions?
    
-
    Section: 27.7 [iostream.format] Status: Open
- Submitter: Martin Sebor Opened: 2001-03-19  Last modified: 2006-12-27
    
-
    View all other issues in [iostream.format].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
 
    
-The descriptions of the constructors of basic_istream<>::sentry
-(27.7.1.1.3 [istream::sentry]) and basic_ostream<>::sentry
-(27.7.2.4 [ostream::sentry]) do not explain what the functions do in
-case an exception is thrown while they execute. Some current
-implementations allow all exceptions to propagate, others catch them
-and set ios_base::badbit instead, still others catch some but let
-others propagate.
+In section 24.1.4 [lib.bidirectdional.iterators], change the return
+type in table 75 from "convertible to T" to
+T&.
 
    
 
 
    
-The text also mentions that the functions may call setstate(failbit)
-(without actually saying on what object, but presumably the stream
-argument is meant).  That may have been fine for
-basic_istream<>::sentry prior to issue 195, since
-the function performs an input operation which may fail. However,
-issue 195 amends 27.7.1.1.3 [istream::sentry], p2 to
-clarify that the function should actually call setstate(failbit |
-eofbit), so the sentence in p3 is redundant or even somewhat
-contradictory.
+In section 24.1.5 [lib.random.access.iterators], change the
+operational semantics for a[n] to " the r-value of
+a[n] is equivalent to the r-value of *(a +
+n)". Add a new row in the table for the expression a[n] = t
+with a return type of convertible to T and operational semantics of
+*(a + n) = t.
 
    
 
-
    
-The same sentence that appears in 27.7.2.4 [ostream::sentry], p3
-doesn't seem to be very meaningful for basic_istream<>::sentry
-which performs no input. It is actually rather misleading since it
-would appear to guide library implementers to calling
-setstate(failbit) when os.tie()->flush(), the only called function,
-throws an exception (typically, it's badbit that's set in response to
-such an event).
-
    
+
    [Lillehammer: Real problem, but should be addressed as part of
+  iterator redesign]
    
 
-
    Additional comments from Martin, who isn't comfortable with the
-    current proposed resolution (see c++std-lib-11530)
    
 
-
    
-The istream::sentry ctor says nothing about how the function
-deals with exemptions (27.6.1.1.2, p1 says that the class is
-responsible for doing "exception safe"(*) prefix and suffix
-operations but it doesn't explain what level of exception
-safety the class promises to provide). The mockup example
-of a "typical implementation of the sentry ctor" given in
-27.6.1.1.2, p6, removed in ISO/IEC 14882:2003, doesn't show
-exception handling, either. Since the ctor is not classified
-as a formatted or unformatted input function, the text in
-27.6.1.1, p1 through p4 does not apply. All this would seem
-to suggest that the sentry ctor should not catch or in any
-way handle exceptions thrown from any functions it may call.
-Thus, the typical implementation of an istream extractor may
-look something like [1].
-
    
 
-
    
-The problem with [1] is that while it correctly sets ios::badbit
-if an exception is thrown from one of the functions called from
-the sentry ctor, if the sentry ctor reaches EOF while extracting
-whitespace from a stream that has eofbit or failbit set in
-exceptions(), it will cause an ios::failure to be thrown, which
-will in turn cause the extractor to set ios::badbit.
-
    
 
-
    
-The only straightforward way to prevent this behavior is to
-move the definition of the sentry object in the extractor
-above the try block (as suggested by the example in 22.2.8,
-p9 and also indirectly supported by 27.6.1.3, p1). See [2].
-But such an implementation will allow exceptions thrown from
-functions called from the ctor to freely propagate to the
-caller regardless of the setting of ios::badbit in the stream
-object's exceptions().
-
    
+
    Rationale:
    
+
    [
+San Francisco:
+]
    
 
-
    
-So since neither [1] nor [2] behaves as expected, the only
-possible solution is to have the sentry ctor catch exceptions
-thrown from called functions, set badbit, and propagate those
-exceptions if badbit is also set in exceptions(). (Another
-solution exists that deals with both kinds of sentries, but
-the code is non-obvious and cumbersome -- see [3].)
-
    
 
-
    
-Please note that, as the issue points out, current libraries
-do not behave consistently, suggesting  that implementors are
-not quite clear on the exception handling in istream::sentry,
-despite the fact that some LWG members might feel otherwise.
-(As documented by the parenthetical comment here:
-http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/2003/n1480.html#309)
-
    
+
    
+Solved by
+N2758.
+
    
 
-
    
-Also please note that those LWG members who in Copenhagen
-felt that "a sentry's constructor should not catch exceptions,
-because sentries should only be used within (un)formatted input
-functions and that exception handling is the responsibility of
-those functions, not of the sentries," as noted here
-http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/2001/n1310.html#309
-would in effect be either arguing for the behavior described
-in [1] or for extractors implemented along the lines of [3].
-
    
 
-
    
-The original proposed resolution (Revision 25 of the issues
-list) clarifies the role of the sentry ctor WRT exception
-handling by making it clear that extractors (both library
-or user-defined) should be implemented along the lines of
-[2] (as opposed to [1]) and that no exception thrown from
-the callees should propagate out of either function unless
-badbit is also set in exceptions().
-
    
 
 
-
    [1] Extractor that catches exceptions thrown from sentry:
    
 
-
    
-
    struct S { long i; };
 
-istream& operator>> (istream &strm, S &s)
-{
-    ios::iostate err = ios::goodbit;
-    try {
-        const istream::sentry guard (strm, false);
-        if (guard) {
-            use_facet<num_get<char> >(strm.getloc ())
-                .get (istreambuf_iterator<char>(strm),
-                      istreambuf_iterator<char>(),
-                      strm, err, s.i);
-        }
-    }
-    catch (...) {
-        bool rethrow;
-        try {
-            strm.setstate (ios::badbit);
-            rethrow = false;
-        }
-        catch (...) {
-            rethrow = true;
-        }
-        if (rethrow)
-            throw;
-    }
-    if (err)
-        strm.setstate (err);
-    return strm;
-}
-
    
-
    
 
-
    [2] Extractor that propagates exceptions thrown from sentry:
    
+
    
+
    397. ostream::sentry dtor throws exceptions
    
+
    Section: 27.7.2.4 [ostream::sentry] Status: Review
+ Submitter: Martin Sebor Opened: 2003-01-05  Last modified: 2009-07-14
    
+
    View all other issues in [ostream::sentry].
    
+
    View all issues with Review status.
    
+
    Discussion:
    
+    
    
+17.4.4.8, p3 prohibits library dtors from throwing exceptions.
+    
    
+    
    
+27.6.2.3, p4 says this about the ostream::sentry dtor:
+    
    
+    
        -4- If ((os.flags() & ios_base::unitbuf) && !uncaught_exception())
+        is true, calls os.flush().
+    
    
+    
    
+27.6.2.6, p7 that describes ostream::flush() says:
+    
    
+    
        -7- If rdbuf() is not a null pointer, calls rdbuf()->pubsync().
+        If that function returns ?-1 calls setstate(badbit) (which
+        may throw ios_base::failure (27.4.4.3)).
+    
    
+    
    
+That seems like a defect, since both pubsync() and setstate() can
+throw an exception. 
+    
    
+
    [
+The contradiction is real.  Clause 17 says destructors may never
+throw exceptions, and clause 27 specifies a destructor that does
+throw.  In principle we might change either one.  We're leaning
+toward changing clause 17: putting in an "unless otherwise specified"
+clause, and then putting in a footnote saying the sentry destructor
+is the only one that can throw.  PJP suggests specifying that
+sentry::~sentry() should internally catch any exceptions it might cause.
+]
    
+
+
+
    [
+See 418 and 622 for related issues.
+]
    
+
+
+
    [
+2009-07 Frankfurt
+]
    
+
 
 
    
-
    istream& operator>> (istream &strm, S &s)
-{
-    istream::sentry guard (strm, false);
-    if (guard) {
-        ios::iostate err = ios::goodbit;
-        try {
-            use_facet<num_get<char> >(strm.getloc ())
-                .get (istreambuf_iterator<char>(strm),
-                      istreambuf_iterator<char>(),
-                      strm, err, s.i);
-        }
-        catch (...) {
-            bool rethrow;
-            try {
-                strm.setstate (ios::badbit);
-                rethrow = false;
-            }
-            catch (...) {
-                rethrow = true;
-            }
-            if (rethrow)
-                throw;
-        }
-        if (err)
-            strm.setstate (err);
-    }
-    return strm;
-}
-
    
+
    
+Move to Review. Add "Throws: nothing" to the specification of ostream::sentry::~sentry().
+
    
 
    
 
+
+
+
    Proposed resolution:
    
 
    
-[3] Extractor that catches exceptions thrown from sentry
-but doesn't set badbit if the exception was thrown as a
-result of a call to strm.clear().
+Add after 27.7.2.4 [ostream::sentry] p17:
 
    
 
 
    
-
    istream& operator>> (istream &strm, S &s)
-{
-    const ios::iostate state = strm.rdstate ();
-    const ios::iostate except = strm.exceptions ();
-    ios::iostate err = std::ios::goodbit;
-    bool thrown = true;
-    try {
-        const istream::sentry guard (strm, false);
-        thrown = false;
-        if (guard) {
-            use_facet<num_get<char> >(strm.getloc ())
-                .get (istreambuf_iterator<char>(strm),
-                      istreambuf_iterator<char>(),
-                      strm, err, s.i);
-        }
-    }
-    catch (...) {
-        if (thrown && state & except)
-            throw;
-        try {
-            strm.setstate (ios::badbit);
-            thrown = false;
-        }
-        catch (...) {
-            thrown = true;
-        }
-        if (thrown)
-            throw;
-    }
-    if (err)
-        strm.setstate (err);
-
-    return strm;
-}
+
    ~sentry();
 
    
+
    
+
    
+-17- If ((os.flags() & ios_base::unitbuf) && !uncaught_exception())
+is true, calls os.flush().
+
    
+
+
    
+Throws: Nothing.
+
    
 
    
+
    
+
+
+
 
+
+
    
+
    408. Is vector<reverse_iterator<char*> > forbidden?
    
+
    Section: 24.2 [iterator.concepts] Status: Review
+ Submitter: Nathan Myers Opened: 2003-06-03  Last modified: 2009-07-31
    
+
    View other active issues in [iterator.concepts].
    
+
    View all other issues in [iterator.concepts].
    
+
    View all issues with Review status.
    
+
    Discussion:
    
 
    
-[Pre-Berlin] Reopened at the request of Paolo Carlini and Steve Clamage.
+I've been discussing iterator semantics with Dave Abrahams, and a 
+surprise has popped up.  I don't think this has been discussed before.
 
    
 
 
    
-[Pre-Portland] A relevant newsgroup post:
+24.2 [iterator.concepts] says that the only operation that can be performed on "singular"
+iterator values is to assign a non-singular value to them.  (It 
+doesn't say they can be destroyed, and that's probably a defect.)  
+Some implementations have taken this to imply that there is no need 
+to initialize the data member of a reverse_iterator<> in the default
+constructor.  As a result, code like
 
    
-
+
      std::vector<std::reverse_iterator<char*> > v(7);
+  v.reserve(1000);
+
    
 
    
-The current proposed resolution of issue #309
-(http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#309)  is
-unacceptable.   I write commerical software and coding around this
-makes my code ugly, non-intuitive, and requires comments referring
-people to this very issue.   Following is the full explanation of my
-experience.
+invokes undefined behavior, because it must default-initialize the
+vector elements, and then copy them to other storage.  Of course many 
+other vector operations on these adapters are also left undefined,
+and which those are is not reliably deducible from the standard.
 
    
+
 
    
-In the course of writing software for commercial use, I constructed
-std::ifstream's based on user-supplied pathnames on typical POSIX
-systems.
+I don't think that 24.1 was meant to make standard-library iterator 
+types unsafe.  Rather, it was meant to restrict what operations may 
+be performed by functions which take general user- and standard 
+iterators as arguments, so that raw pointers would qualify as
+iterators.  However, this is not clear in the text, others have come 
+to the opposite conclusion.
 
    
+
 
    
-It was expected that some files that opened successfully might not read
-successfully -- such as a pathname which actually refered to a
-directory.   Intuitively, I expected the streambuffer underflow() code
-to throw an exception in this situation, and recent implementations of
-libstdc++'s basic_filebuf do just that (as well as many of my own
-custom streambufs).
+One question is whether the standard iterator adaptors have defined
+copy semantics.  Another is whether they have defined destructor
+semantics: is
 
    
+
      { std::vector<std::reverse_iterator<char*> >  v(7); }
+
    
 
    
-I also intuitively expected that the istream code would convert these
-exceptions to the "badbit' set on the stream object, because I had not
-requested exceptions.    I refer to 27.6.1.1. P4.
+undefined too?
 
    
+
 
    
-However, this was not the case on at least two implementations -- if
-the first thing I did with an istream was call operator>>( T& ) for T
-among the basic arithmetic types and std::string.   Looking further I
-found that the sentry's constructor was invoking the exception when it
-pre-scanned for whitespace, and the extractor function (operator>>())
-was not catching exceptions in this situation.
+Note this is not a question of whether algorithms are allowed to
+rely on copy semantics for arbitrary iterators, just whether the
+types we actually supply support those operations.  I believe the 
+resolution must be expressed in terms of the semantics of the 
+adapter's argument type.  It should make clear that, e.g., the 
+reverse_iterator<T> constructor is actually required to execute
+T(), and so copying is defined if the result of T() is copyable.
 
    
+
 
    
-So, I was in a situation where setting 'noskipws' would change the
-istream's behavior even though no characters (whitespace or not) could
-ever be successfully read.
+Issue 235, which defines reverse_iterator's default
+constructor more precisely, has some relevance to this issue.
+However, it is not the whole story.
 
    
+
 
    
-Also, calling .peek() on the istream before calling the extractor()
-changed the behavior (.peek() had the effect of setting the badbit
-ahead of time).
+The issue was whether 
 
    
+
      reverse_iterator() { }
+
    
 
    
-I found this all to be so inconsistent and inconvenient for me and my
-code design, that I filed a bugzilla entry for libstdc++.   I was then
-told that the bug cannot be fixed until issue #309 is resolved by the
-committee.
+is allowed, vs. 
 
    
-
-
-
-
    Proposed resolution:
    
-
-
-
    Rationale:
    
-
    The LWG agrees there is minor variation between implementations,
-  but believes that it doesn't matter. This is a rarely used corner
-  case. There is no evidence that this has any commercial importance
-  or that it causes actual portability problems for customers trying
-  to write code that runs on multiple implementations.
    
-
-
-
-
-
-
    
-
    342. seek and eofbit
    
-
    Section: 27.7.1.3 [istream.unformatted] Status: Open
- Submitter: Howard Hinnant Opened: 2001-10-09  Last modified: 2007-01-15
    
-
    View all other issues in [istream.unformatted].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    I think we have a defect.
    
-
-
    According to lwg issue 60 which is now a dr, the
-description of seekg in 27.7.1.3 [istream.unformatted] paragraph 38 now looks
-like:
    
-
-
    
-Behaves as an unformatted input function (as described in 27.6.1.3, 
-paragraph 1), except that it does not count the number of characters 
-extracted and does not affect the value returned by subsequent calls to 
-gcount(). After constructing a sentry object, if fail() != true, 
-executes rdbuf()->pubseekpos( pos).
-
    
-
-
    And according to lwg issue 243 which is also now a dr,
-27.6.1.3, paragraph 1 looks like:
    
-
-
    
-Each unformatted input function begins execution by constructing an 
-object of class sentry with the default argument noskipws (second) 
-argument true. If the sentry object returns true, when converted to a 
-value of type bool, the function endeavors to obtain the requested 
-input.  Otherwise, if the sentry constructor exits by throwing an 
-exception or if the sentry object returns false, when converted to a 
-value of type bool, the function returns without attempting to obtain 
-any input. In either case the number of extracted characters is set to 
-0; unformatted input functions taking a character array of non-zero 
-size as an argument shall also store a null character (using charT()) 
-in the first location of the array. If an exception is thrown during 
-input then ios::badbit is turned on in *this'ss error state. If 
-(exception()&badbit)!= 0 then the exception is rethrown. It also counts 
-the number of characters extracted. If no exception has been thrown it 
-ends by storing the count in a member object and returning the value 
-specified. In any event the sentry object is destroyed before leaving 
-the unformatted input function.
-
    
-
-
    And finally 27.6.1.1.2/5 says this about sentry:
    
-
-
    
-If, after any preparation is completed, is.good() is true, ok_ != false 
-otherwise, ok_ == false.
-
    
+
      reverse_iterator() : current() { }
+
    
 
 
    
-So although the seekg paragraph says that the operation proceeds if 
-!fail(), the behavior of unformatted functions says the operation 
-proceeds only if good().  The two statements are contradictory when only 
-eofbit is set.  I don't think the current text is clear which condition 
-should be respected.
+The difference is when T is char*, where the first leaves the member
+uninitialized, and possibly equal to an existing pointer value, or
+(on some targets) may result in a hardware trap when copied.
 
    
 
-
    Further discussion from Redmond:
    
-
-
    PJP: It doesn't seem quite right to say that seekg is
-"unformatted". That makes specific claims about sentry that
-aren't quite appropriate for seeking, which has less fragile failure
-modes than actual input.  If we do really mean that it's unformatted
-input, it should behave the same way as other unformatted input.  On
-the other hand, "principle of least surprise" is that seeking from EOF
-ought to be OK.
    
-
 
    
-Pre-Berlin:  Paolo points out several problems with the proposed resolution in
-Ready state:
+8.5 paragraph 5 seems to make clear that the second is required to
+satisfy DR 235, at least for non-class Iterator argument
+types.
 
    
 
-
      
-
    • It should apply to both overloads of seekg.
      • 
-
    • tellg has similar issues, except that it should not call clear().
      • 
-
    • The point about clear() seems to apply to seekp().
      • 
-
    • Depending on the outcome of 419
-if the sentry
-sets failbit when it finds eofbit already set, then
-you can never seek away from the end of stream.
      • 
-
    
-
-
-
-
    Proposed resolution:
    
-
-
    Change 27.7.1.3 [istream.unformatted] to:
    
-
    
-Behaves as an unformatted input function (as described in 27.6.1.3,
-paragraph 1), except that it does not count the number of characters
-extracted, does not affect the value returned by subsequent calls to
-gcount(), and does not examine the value returned by the sentry
-object. After constructing a sentry object, if fail() !=
-true, executes rdbuf()->pubseekpos(pos).  In
-case of success, the function calls clear().
-In case of failure, the function calls setstate(failbit)
-(which may throw ios_base::failure).
-
    
-
-
    [Lillehammer: Matt provided wording.]
    
+
    
+But that only takes care of reverse_iterator, and doesn't establish
+a policy for all iterators.  (The reverse iterator adapter was just
+an example.)  In particular, does my function
+
    
+
      template <typename Iterator>
+    void f() { std::vector<Iterator>  v(7); } 
+
    
+
    
+evoke undefined behavior for some conforming iterator definitions?
+I think it does, now, because vector<> will destroy those singular
+iterator values, and that's explicitly disallowed.
+
    
 
+
    
+24.1 shouldn't give blanket permission to copy all singular iterators,
+because then pointers wouldn't qualify as iterators.  However, it
+should allow copying of that subset of singular iterator values that
+are default-initialized, and it should explicitly allow destroying any
+iterator value, singular or not, default-initialized or not.
+
    
 
+
    Related issues: 407, 1012
    
+
    [
+We don't want to require all singular iterators to be copyable,
+because that is not the case for pointers.  However, default
+construction may be a special case.  Issue: is it really default
+construction we want to talk about, or is it something like value
+initialization?  We need to check with core to see whether default
+constructed pointers are required to be copyable; if not, it would be
+wrong to impose so strict a requirement for iterators.
+]
    
 
 
-
    Rationale:
    
-
    In C, fseek does clear EOF.  This is probably what most users would
-  expect.  We agree that having eofbit set should not deter a seek,
-  and that a successful seek should clear eofbit. Note
-  that fail() is true only if failbit
-  or badbit is set, so using !fail(), rather
-  than good(), satisfies this goal.
    
+
    [
+2009-05-10 Alisdair provided wording.
+]
    
 
 
+
    
+The comments regarding destroying singular iterators have already been
+resolved.  That just leaves copying (with moving implied).
+
    
 
+
    [
+2009-07 Frankfurt
+]
    
 
 
-
    
-
    343. Unspecified library header dependencies
    
-
    Section: 17 [library] Status: Open
- Submitter: Martin Sebor Opened: 2001-10-09  Last modified: 2009-03-11
    
-
    View other active issues in [library].
    
-
    View all other issues in [library].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
+
    
 
    
-The synopses of the C++ library headers clearly show which names are
-required to be defined in each header. Since in order to implement the
-classes and templates defined in these headers declarations of other
-templates (but not necessarily their definitions) are typically
-necessary the standard in 17.4.4, p1 permits library implementers to
-include any headers needed to implement the definitions in each header.
+This is related to LWG 1012.
 
    
-
 
    
-For instance, although it is not explicitly specified in the synopsis of
-<string>, at the point of definition of the std::basic_string template
-the declaration of the std::allocator template must be in scope. All
-current implementations simply include <memory> from within <string>,
-either directly or indirectly, to bring the declaration of
-std::allocator into scope.
+Note that there is a bug in the proposed resolution to LWG 1012. The
+change to  [reverse.iter.con] should be modified so that the word
+"default" in the second sentence of the Effects clause is replaced by
+"value."
 
    
-
 
    
-Additionally, however, some implementation also include <istream> and
-<ostream> at the top of <string> to bring the declarations of
-std::basic_istream and std::basic_ostream into scope (which are needed
-in order to implement the string inserter and extractor operators
-(21.3.7.9 [lib.string.io])). Other implementations only include
-<iosfwd>, since strictly speaking, only the declarations and not the
-full definitions are necessary.
+We believe that the proposed fix to LWG 1012 (now corrected) is
+sufficient to solve the problem for reverse_iterator. However, Alisdair
+pointed out that LWG 1012 does not solve the general problem for authors
+of iterator adaptors.
 
    
-
 
    
-Obviously, it is possible to implement <string> without actually
-providing the full definitions of all the templates std::basic_string
-uses (std::allocator, std::basic_istream, and std::basic_ostream).
-Furthermore, not only is it possible, doing so is likely to have a
-positive effect on compile-time efficiency.
+There are some problems with the proposed resolution. The phrase "safely
+copyable" is not a term of art. Also, it mentions a
+DefaultConstructible? concept.
 
    
-
 
    
-But while it may seem perfectly reasonable to expect a program that uses
-the std::basic_string insertion and extraction operators to also
-explicitly include <istream> or <ostream>, respectively, it doesn't seem
-reasonable to also expect it to explicitly include <memory>. Since
-what's reasonable and what isn't is highly subjective one would expect
-the standard to specify what can and what cannot be assumed.
-Unfortunately, that isn't the case.
+Move to Review after Alisdair updates the wording.
 
    
+
    
 
-
    The examples below demonstrate the issue.
    
-
-
    Example 1:
    
+
    [
+2009-07-31 Alisdair revised wording:
+]
    
 
-
    It is not clear whether the following program is complete:
    
 
-
    #include <string>
 
-extern std::basic_ostream<char> &strm;
 
-int main () {
-    strm << std::string ("Hello, World!\n");
-}
-
        
+
    Proposed resolution:
    
+
    
+Add a new paragrpah to Iterator concepts 24.2 [iterator.concepts] after para 5 (the one
+describing singular iterators)
+
    
+
    
+
    
+Just as a regular pointer to an array guarantees that there is a pointer
+value pointing past the last element of the array, so for any iterator
+type there is an iterator value that points past the last element of a
+corresponding container. These values are called past-the-end values.
+Values of an iterator i for which the expression *i is defined are called
+dereferenceable. The library never assumes that past-the-end values are
+dereferenceable. Iterators can also have singular values that are not
+associated with any container. [Example: After the declaration of an
+uninitialized pointer x (as with int* x;), x must always be assumed to
+have a singular value of a pointer. — end example] Results of most
+expressions are undefined for singular values; the only exceptions are
+destroying an iterator that holds a singular value and the assignment of
+a non-singular value to an iterator that holds a singular value. In this
+case the singular value is overwritten the same way as any other value.
+Dereferenceable values are always non-singular.
+
    
+
    
+After value-initialization, any iterator that satisfies the
+DefaultConstructible concept shall not introduce undefined behaviour
+when used the source of a copy or move operation, even if it would
+otherwise be singular. [Note: This guarantee is not offered for
+default-initialization (8.5 [dcl.init]), although the distinction only
+matters for types with trivial default constructors such as pointers. —
+end note]
+
    
 
-
    or whether one must explicitly include <memory> or
-<ostream> (or both) in addition to <string> in order for
-the program to compile.
    
 
+
    
 
-
    Example 2:
    
 
-
    Similarly, it is unclear whether the following program is complete:
    
 
-
    #include <istream>
 
-extern std::basic_iostream<char> &strm;
 
-int main () {
-    strm << "Hello, World!\n";
-}
-
    
 
-
    
-or whether one needs to explicitly include <ostream>, and
-perhaps even other headers containing the definitions of other
-required templates:
    
+
    
+
    419. istream extractors not setting failbit if eofbit is already set
    
+
    Section: 27.7.1.1.3 [istream::sentry] Status: Ready
+ Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2009-07-14
    
+
    View all other issues in [istream::sentry].
    
+
    View all issues with Ready status.
    
+
    Discussion:
    
+        
    
 
-
    #include <ios>
-#include <istream>
-#include <ostream>
-#include <streambuf>
-
-extern std::basic_iostream<char> &strm;
+27.7.1.1.3 [istream::sentry], p2 says that istream::sentry ctor prepares for input if is.good()
+is true. p4 then goes on to say that the ctor sets the sentry::ok_ member to
+true if the stream state is good after any preparation. 27.7.1.2.1 [istream.formatted.reqmts], p1 then
+says that a formatted input function endeavors to obtain the requested input
+if the sentry's operator bool() returns true.
 
-int main () {
-    strm << "Hello, World!\n";
-}
-
    
+Given these requirements, no formatted extractor should ever set failbit if
+the initial stream rdstate() == eofbit. That is contrary to the behavior of
+all implementations I tested. The program below prints out
 
-
    Example 3:
    
+eof = 1, fail = 0
+eof = 1, fail = 1
 
-
    Likewise, it seems unclear whether the program below is complete:
    
-
    #include <iterator>
+on all of them.
+        
    
+
    +#include <sstream>
+#include <cstdio>
 
-bool foo (std::istream_iterator<int> a, std::istream_iterator<int> b)
+int main()
 {
-    return a == b;
-}
+    std::istringstream strm ("1");
 
-int main () { }
-
    
+    int i = 0;
+
+    strm >> i;
 
-
    or whether one should be required to include <istream>.
    
+    std::printf ("eof = %d, fail = %d\n",
+                 !!strm.eof (), !!strm.fail ());
 
-
    There are many more examples that demonstrate this lack of a
-requirement.  I believe that in a good number of cases it would be
-unreasonable to require that a program explicitly include all the
-headers necessary for a particular template to be specialized, but I
-think that there are cases such as some of those above where it would
-be desirable to allow implementations to include only as much as
-necessary and not more.
    
+    strm >> i;
 
-
    [
-post Bellevue:
-]
    
+    std::printf ("eof = %d, fail = %d\n",
+                 !!strm.eof (), !!strm.fail ());
+}
 
+
    
+        
    
+
    
 
-
    
-Position taken in prior reviews is that the idea of a table of header
-dependencies is a good one. Our view is that a full paper is needed to
-do justice to this, and we've made that recommendation to the issue
-author.
-
    
+Comments from Jerry Schwarz (c++std-lib-11373):
+
    
 
+Jerry Schwarz wrote:
+
    
 
+I don't know where (if anywhere) it says it in the standard, but the
+formatted extractors are supposed to set failbit if they don't extract
+any characters. If they didn't then simple loops like
+
    
 
-
    Proposed resolution:
    
-
    
-For every C++ library header, supply a minimum set of other C++ library
-headers that are required to be included by that header. The proposed
-list is below (C++ headers for C Library Facilities, table 12 in
-17.4.1.2, p3, are omitted):
-
    
-
-
    +------------+--------------------+
-| C++ header |required to include |
-+============+====================+
-|<algorithm> |                    |
-+------------+--------------------+
-|<bitset>    |                    |
-+------------+--------------------+
-|<complex>   |                    |
-+------------+--------------------+
-|<deque>     |<memory>            |
-+------------+--------------------+
-|<exception> |                    |
-+------------+--------------------+
-|<fstream>   |<ios>               |
-+------------+--------------------+
-|<functional>|                    |
-+------------+--------------------+
-|<iomanip>   |<ios>               |
-+------------+--------------------+
-|<ios>       |<streambuf>         |
-+------------+--------------------+
-|<iosfwd>    |                    |
-+------------+--------------------+
-|<iostream>  |<istream>, <ostream>|
-+------------+--------------------+
-|<istream>   |<ios>               |
-+------------+--------------------+
-|<iterator>  |                    |
-+------------+--------------------+
-|<limits>    |                    |
-+------------+--------------------+
-|<list>      |<memory>            |
-+------------+--------------------+
-|<locale>    |                    |
-+------------+--------------------+
-|<map>       |<memory>            |
-+------------+--------------------+
-|<memory>    |                    |
-+------------+--------------------+
-|<new>       |<exception>         |
-+------------+--------------------+
-|<numeric>   |                    |
-+------------+--------------------+
-|<ostream>   |<ios>               |
-+------------+--------------------+
-|<queue>     |<deque>             |
-+------------+--------------------+
-|<set>       |<memory>            |
-+------------+--------------------+
-|<sstream>   |<ios>, <string>     |
-+------------+--------------------+
-|<stack>     |<deque>             |
-+------------+--------------------+
-|<stdexcept> |                    |
-+------------+--------------------+
-|<streambuf> |<ios>               |
-+------------+--------------------+
-|<string>    |<memory>            |
-+------------+--------------------+
-|<strstream> |                    |
-+------------+--------------------+
-|<typeinfo>  |<exception>         |
-+------------+--------------------+
-|<utility>   |                    |
-+------------+--------------------+
-|<valarray>  |                    |
-+------------+--------------------+
-|<vector>    |<memory>            |
-+------------+--------------------+
-
    
+while (cin >> x);
+
    
 
+would loop forever.
+
    
 
-
    Rationale:
    
-
    The portability problem is real.  A program that works correctly on
-one implementation might fail on another, because of different header
-dependencies.  This problem was understood before the standard was
-completed, and it was a conscious design choice.
    
-
    One possible way to deal with this, as a library extension, would
-be an <all> header.
    
+Further comments from Martin Sebor:
+
    
 
+The question is which part of the extraction should prevent this from happening
+by setting failbit when eofbit is already set. It could either be the sentry
+object or the extractor. It seems that most implementations have chosen to
+set failbit in the sentry [...] so that's the text that will need to be
+corrected. 
+
+        
    
 
    
-Hinnant:  It's time we dealt with this issue for C++0X.  Reopened.
+Pre Berlin:  This issue is related to 342.  If the sentry
+sets failbit when it finds eofbit already set, then
+you can never seek away from the end of stream.
 
    
+
    Kona: Possibly NAD.  If eofbit is set then good() will return false.  We
+  then set ok to false.  We believe that the sentry's
+  constructor should always set failbit when ok is false, and
+  we also think the standard already says that.  Possibly it could be
+  clearer.
     
 
 
+
    [
+2009-07 Frankfurt
+]
    
 
 
+
    
+Moved to Ready.
+
    
 
+    
 
-
-
    
-
    382. codecvt do_in/out result
    
-
    Section: 22.4.1.4 [locale.codecvt] Status: Open
- Submitter: Martin Sebor Opened: 2002-08-30  Last modified: 2007-01-15
    
-
    View other active issues in [locale.codecvt].
    
-
    View all other issues in [locale.codecvt].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
+
    Proposed resolution:
    
 
    
-It seems that the descriptions of codecvt do_in() and do_out() leave
-sufficient room for interpretation so that two implementations of
-codecvt may not work correctly with the same filebuf. Specifically,
-the following seems less than adequately specified:
+Change 27.7.1.1.3 [istream::sentry], p2 to:
 
    
 
-
      
-
    1. 
-  the conditions under which the functions terminate
-
      2. 
-
    2. 
-  precisely when the functions return ok
-
      3. 
-
    3. 
-  precisely when the functions return partial
-
      4. 
-
    4. 
-  the full set of conditions when the functions return error
-
      5. 
-
    
-
-
      
-
    1. 
-   22.4.1.4.2 [locale.codecvt.virtuals], p2 says this about the effects of the
-   function: ...Stops if it encounters a character it cannot
-   convert...  This assumes that there *is* a character to
-   convert. What happens when there is a sequence that doesn't form a
-   valid source character, such as an unassigned or invalid UNICODE
-   character, or a sequence that cannot possibly form a character
-   (e.g., the sequence "\xc0\xff" in UTF-8)?
-
      2. 
-
    2. 
-   Table 53 says that the function returns codecvt_base::ok
-   to indicate that the function(s) "completed the conversion."
-   Suppose that the source sequence is "\xc0\x80" in UTF-8,
-   with from pointing to '\xc0' and (from_end==from + 1).
-   It is not clear whether the return value should be ok
-   or partial (see below).
-
      3. 
-
    3. 
-   Table 53 says that the function returns codecvt_base::partial
-   if "not all source characters converted." With the from pointers
-   set up the same way as above, it is not clear whether the return
-   value should be partial or ok (see above).
-
      4. 
-
    4. 
-   Table 53, in the row describing the meaning of error mistakenly
-   refers to a "from_type" character, without the symbol from_type
-   having been defined. Most likely, the word "source" character
-   is intended, although that is not sufficient. The functions
-   may also fail when they encounter an invalid source sequence
-   that cannot possibly form a valid source character (e.g., as
-   explained in bullet 1 above).
-
      5. 
-
    
-
    
-Finally, the conditions described at the end of 22.4.1.4.2 [locale.codecvt.virtuals], p4 don't seem to be possible:
-
    
-
    
-    "A return value of partial, if (from_next == from_end),
-    indicates that either the destination sequence has not
-    absorbed all the available destination elements, or that
-    additional source elements are needed before another
-    destination element can be produced."
-
    
-
    
-If the value is partial, it's not clear to me that (from_next
-==from_end) could ever hold if there isn't enough room
-in the destination buffer. In order for (from_next==from_end) to
-hold, all characters in that range must have been successfully
-converted (according to 22.4.1.4.2 [locale.codecvt.virtuals], p2) and since there are no
-further source characters to convert, no more room in the
-destination buffer can be needed.
-
    
-
    
-It's also not clear to me that (from_next==from_end) could ever
-hold if additional source elements are needed to produce another
-destination character (not element as incorrectly stated in the
-text). partial is returned if "not all source characters have
-been converted" according to Table 53, which also implies that
-(from_next==from) does NOT hold.
-
    
-
    
-Could it be that the intended qualifying condition was actually
-(from_next != from_end), i.e., that the sentence was supposed
-to read
-
    
-
    
-    "A return value of partial, if (from_next != from_end),..."
-
    
+
    
+
    explicit sentry(basic_istream<charT,traits>& is , bool noskipws = false);
    
 
    
-which would make perfect sense, since, as far as I understand it,
-partial can only occur if (from_next != from_end)?
+-2- Effects: If is.good() is true
+false, calls is.setstate(failbit). 
+Otherwise prepares for formatted or unformatted input. ...
 
    
-
    [Lillehammer: Defer for the moment, but this really needs to be
-  fixed. Right now, the description of codecvt is too vague for it to
-  be a useful contract between providers and clients of codecvt
-  facets.  (Note that both vendors and users can be both providers and
-  clients of codecvt facets.) The major philosophical issue is whether
-  the standard should only describe mappings that take a single wide
-  character to multiple narrow characters (and vice versa), or whether
-  it should describe fully general N-to-M conversions. When the
-  original standard was written only the former was contemplated, but
-  today, in light of the popularity of utf8 and utf16, that doesn't
-  seem sufficient for C++0x. Bill supports general N-to-M conversions;
-  we need to make sure Martin and Howard agree.]
    
-
+
    
 
 
-
    Proposed resolution:
    
 
 
 
 
 
    
-
    394. behavior of formatted output on failure
    
-
    Section: 27.7.2.6.1 [ostream.formatted.reqmts] Status: Open
- Submitter: Martin Sebor Opened: 2002-12-27  Last modified: 2007-01-15
    
+
    427. stage 2 and rationale of DR 221
    
+
    Section: 22.4.2.1.2 [facet.num.get.virtuals] Status: Open
+ Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2009-07-14
    
+
    View other active issues in [facet.num.get.virtuals].
    
+
    View all other issues in [facet.num.get.virtuals].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-There is a contradiction in Formatted output about what bit is
-supposed to be set if the formatting fails. On sentence says it's
-badbit and another that it's failbit.
-
    
-
    
-27.6.2.5.1, p1 says in the Common Requirements on Formatted output
-functions:
-
    
-
         ... If the generation fails, then the formatted output function
-     does setstate(ios::failbit), which might throw an exception.
-
    
-
    
-27.6.2.5.2, p1 goes on to say this about Arithmetic Inserters:
+The requirements specified in Stage 2 and reiterated in the rationale
+of DR 221 (and echoed again in DR 303) specify that num_get<charT>::
+do_get() compares characters on the stream against the widened elements
+of "012...abc...ABCX+-"
 
    
+
 
    
-     ... The formatting conversion occurs as if it performed the
-     following code fragment:
+An implementation is required to allow programs to instantiate the num_get
+template on any charT that satisfies the requirements on a user-defined
+character type. These requirements do not include the ability of the
+character type to be equality comparable (the char_traits template must
+be used to perform tests for equality). Hence, the num_get template cannot
+be implemented to support any arbitrary character type. The num_get template
+must either make the assumption that the character type is equality-comparable
+(as some popular implementations do), or it may use char_traits<charT> to do
+the comparisons (some other popular implementations do that). This diversity
+of approaches makes it difficult to write portable programs that attempt to
+instantiate the num_get template on user-defined types.
 
    
-
         bool failed =
-         use_facet<num_put<charT,ostreambuf_iterator<charT,traits>
-         > >
-         (getloc()).put(*this, *this, fill(), val). failed();
 
-     ... If failed is true then does setstate(badbit) ...
-
    
+
    [Kona: the heart of the problem is that we're theoretically
+  supposed to use traits classes for all fundamental character
+  operations like assignment and comparison, but facets don't have
+  traits parameters.  This is a fundamental design flaw and it
+  appears all over the place, not just in this one place.  It's not
+  clear what the correct solution is, but a thorough review of facets
+  and traits is in order.  The LWG considered and rejected the
+  possibility of changing numeric facets to use narrowing instead of
+  widening.  This may be a good idea for other reasons (see issue
+  459), but it doesn't solve the problem raised by this
+  issue.  Whether we use widen or narrow the num_get facet
+  still has no idea which traits class the user wants to use for 
+  the comparison, because only streams, not facets, are passed traits
+  classes.   The standard does not require that two different
+  traits classes with the same char_type must necessarily 
+  have the same behavior.]
    
+
+
+
    Informally, one possibility: require that some of the basic
+character operations, such as eq, lt,
+and assign, must behave the same way for all traits classes
+with the same char_type.  If we accept that limitation on
+traits classes, then the facet could reasonably be required to
+use char_traits<charT>.
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
 
    
-The original intent of the text, according to Jerry Schwarz (see
-c++std-lib-10500), is captured in the following paragraph:
+There was general agreement that the standard only needs to specify the
+behavior when the character type is char or wchar_t.
 
    
 
    
-In general "badbit" should mean that the stream is unusable because
-of some underlying failure, such as disk full or socket closure;
-"failbit" should mean that the requested formatting wasn't possible
-because of some inconsistency such as negative widths.  So typically
-if you clear badbit and try to output something else you'll fail
-again, but if you clear failbit and try to output something else
-you'll succeed.
+Beman: we don't need to worry about C++1x because there is a non-zero
+possibility that we would have a replacement facility for iostreams that
+would solve these problems.
 
    
 
    
-In the case of the arithmetic inserters, since num_put cannot
-report failure by any means other than exceptions (in response
-to which the stream must set badbit, which prevents the kind of
-recoverable error reporting mentioned above), the only other
-detectable failure is if the iterator returned from num_put
-returns true from failed().
+We need to change the following sentence in [locale.category], paragraph
+6 to specify that C is char and wchar_t:
 
    
 
    
-Since that can only happen (at least with the required iostream
-specializations) under such conditions as the underlying failure
-referred to above (e.g., disk full), setting badbit would seem
-to be the appropriate response (indeed, it is required in
-27.6.2.5.2, p1). It follows that failbit can never be directly
-set by the arithmetic (it can only be set by the sentry object
-under some unspecified conditions).
+"A template formal parameter with name C represents the set of all
+possible specializations on a parameter that satisfies the requirements
+for a character on which any member of the iostream components can be
+instantiated."
 
    
 
    
-The situation is different for other formatted output functions
-which can fail as a result of the streambuf functions failing
-(they may do so by means other than exceptions), and which are
-then required to set failbit.
+We also need to specify in 27 that the basic character operations, such
+as eq, lt, and assign use std::char_traits.
 
    
 
    
-The contradiction, then, is that ostream::operator<<(int) will
-set badbit if the disk is full, while operator<<(ostream&,
-char) will set failbit under the same conditions. To make the behavior
-consistent, the Common requirements sections for the Formatted output
-functions should be changed as proposed below.
+Daniel volunteered to provide wording.
 
    
-
    [Kona: There's agreement that this is a real issue.  What we
-  decided at Kona: 1. An error from the buffer (which can be detected
-  either directly from streambuf's member functions or by examining a
-  streambuf_iterator) should always result in badbit getting set.
-  2. There should never be a circumstance where failbit gets set.
-  That represents a formatting error, and there are no circumstances
-  under which the output facets are specified as signaling a
-  formatting error. (Even more so for string output that for numeric
-  because there's nothing to format.)  If we ever decide to make it
-  possible for formatting errors to exist then the facets can signal
-  the error directly, and that should go in clause 22, not clause 27.
-  3. The phrase "if generation fails" is unclear and should be
-  eliminated.  It's not clear whether it's intended to mean a buffer
-  error (e.g. a full disk), a formatting error, or something else.
-  Most people thought it was supposed to refer to buffer errors; if
-  so, we should say so.  Martin will provide wording.]
    
-
+
    
 
 
 
 
    Proposed resolution:
    
 
 
-
    Rationale:
    
-
-
-
-
 
 
 
    
-
    397. ostream::sentry dtor throws exceptions
    
-
    Section: 27.7.2.4 [ostream::sentry] Status: Open
- Submitter: Martin Sebor Opened: 2003-01-05  Last modified: 2007-07-25
    
-
    View other active issues in [ostream::sentry].
    
-
    View all other issues in [ostream::sentry].
    
-
    View all issues with Open status.
    
+
    430. valarray subset operations
    
+
    Section: 26.6.2.4 [valarray.sub] Status: Ready
+ Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2009-07-14
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
-    
    
-17.4.4.8, p3 prohibits library dtors from throwing exceptions.
-    
    
-    
    
-27.6.2.3, p4 says this about the ostream::sentry dtor:
-    
    
-    
        -4- If ((os.flags() & ios_base::unitbuf) && !uncaught_exception())
-        is true, calls os.flush().
-    
    
-    
    
-27.6.2.6, p7 that describes ostream::flush() says:
-    
    
-    
        -7- If rdbuf() is not a null pointer, calls rdbuf()->pubsync().
-        If that function returns ?-1 calls setstate(badbit) (which
-        may throw ios_base::failure (27.4.4.3)).
-    
    
-    
    
-That seems like a defect, since both pubsync() and setstate() can
-throw an exception. 
-    
    
+
    
+The standard fails to specify the behavior of valarray::operator[](slice)
+and other valarray subset operations when they are passed an "invalid"
+slice object, i.e., either a slice that doesn't make sense at all (e.g.,
+slice (0, 1, 0) or one that doesn't specify a valid subset of the valarray
+object (e.g., slice (2, 1, 1) for a valarray of size 1).
+
    
+
    [Kona: the LWG believes that invalid slices should invoke
+  undefined behavior.  Valarrays are supposed to be designed for high
+  performance, so we don't want to require specific checking.  We
+  need wording to express this decision.]
    
+
+
 
    [
-The contradiction is real.  Clause 17 says destructors may never
-throw exceptions, and clause 27 specifies a destructor that does
-throw.  In principle we might change either one.  We're leaning
-toward changing clause 17: putting in an "unless otherwise specified"
-clause, and then putting in a footnote saying the sentry destructor
-is the only one that can throw.  PJP suggests specifying that
-sentry::~sentry() should internally catch any exceptions it might cause.
+Bellevue:
 ]
    
 
 
+
    
+Please note that the standard also fails to specify the behavior of
+slice_array and gslice_array in the valid case. Bill Plauger will
+endeavor to provide revised wording for slice_array and gslice_array.
+
    
+
 
    [
-See 418 and 622 for related issues.
+post-Bellevue:  Bill provided wording.
 ]
    
 
 
-  
+
    [
+2009-07 Frankfurt
+]
    
 
-
    Proposed resolution:
    
 
+
    
+
    
+Move to Ready.
+
    
+
    
 
 
 
+
    Proposed resolution:
    
+
    
+Insert after 26.6.2.4 [valarray.sub], paragraph 1:
+
    
 
-
    
-
    398. effects of end-of-file on unformatted input functions
    
-
    Section: 27.7.2.4 [ostream::sentry] Status: Open
- Submitter: Martin Sebor Opened: 2003-01-05  Last modified: 2007-01-15
    
-
    View other active issues in [ostream::sentry].
    
-
    View all other issues in [ostream::sentry].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-    
    
-While reviewing unformatted input member functions of istream
-for their behavior when they encounter end-of-file during input
-I found that the requirements vary, sometimes unexpectedly, and
-in more than one case even contradict established practice (GNU
-libstdc++ 3.2, IBM VAC++ 6.0, STLPort 4.5, SunPro 5.3, HP aCC
-5.38, Rogue Wave libstd 3.1, and Classic Iostreams).
-    
    
-    
    
-The following unformatted input member functions set eofbit if they
-encounter an end-of-file (this is the expected behavior, and also
-the behavior of all major implementations):
-    
    
-    
        basic_istream<charT, traits>&
-    get (char_type*, streamsize, char_type);
-    
    
-    
    
-    Also sets failbit if it fails to extract any characters.
-    
    
-    
        basic_istream<charT, traits>&
-    get (char_type*, streamsize);
-    
    
-    
    
-    Also sets failbit if it fails to extract any characters.
-    
    
-    
        basic_istream<charT, traits>&
-    getline (char_type*, streamsize, char_type);
-    
    
-    
    
-    Also sets failbit if it fails to extract any characters.
-    
    
-    
        basic_istream<charT, traits>&
-    getline (char_type*, streamsize);
-    
    
-    
    
-    Also sets failbit if it fails to extract any characters.
-    
    
-    
        basic_istream<charT, traits>&
-    ignore (int, int_type);
-    
    
-    
        basic_istream<charT, traits>&
-    read (char_type*, streamsize);
-    
    
-    
    
-    Also sets failbit if it encounters end-of-file.
-    
    
-    
        streamsize readsome (char_type*, streamsize);
-    
    
-
-    
    
-The following unformated input member functions set failbit but
-not eofbit if they encounter an end-of-file (I find this odd
-since the functions make it impossible to distinguish a general
-failure from a failure due to end-of-file; the requirement is
-also in conflict with all major implementation which set both
-eofbit and failbit):
-    
    
-    
        int_type get();
-    
    
-    
        basic_istream<charT, traits>&
-    get (char_type&);
-    
    
-    
    
-These functions only set failbit of they extract no characters,
-otherwise they don't set any bits, even on failure (I find this
-inconsistency quite unexpected; the requirement is also in
-conflict with all major implementations which set eofbit
-whenever they encounter end-of-file):
-    
    
-    
        basic_istream<charT, traits>&
-    get (basic_streambuf<charT, traits>&, char_type);
-    
    
-    
        basic_istream<charT, traits>&
-    get (basic_streambuf<charT, traits>&);
-    
    
-    
    
-This function sets no bits (all implementations except for
-STLport and Classic Iostreams set eofbit when they encounter
-end-of-file):
-    
    
-    
        int_type peek ();
-    
    
-
    Informally, what we want is a global statement of intent saying
-  that eofbit gets set if we trip across EOF, and then we can take
-  away the specific wording for individual functions.  A full review
-  is necessary.  The wording currently in the standard is a mishmash,
-  and changing it on an individual basis wouldn't make things better.
-  Dietmar will do this work.
    
-  
-
-
    Proposed resolution:
    
-
-
-
-
-
    
-
    408. Is vector<reverse_iterator<char*> > forbidden?
    
-
    Section: 24.2 [iterator.concepts] Status: Open
- Submitter: Nathan Myers Opened: 2003-06-03  Last modified: 2009-05-10
    
-
    View other active issues in [iterator.concepts].
    
-
    View all other issues in [iterator.concepts].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
+
    
 
    
-I've been discussing iterator semantics with Dave Abrahams, and a 
-surprise has popped up.  I don't think this has been discussed before.
+The member operator is overloaded to provide several ways to select
+sequences
+of elements from among those controlled by *this. The first group of five
+member operators work in conjunction with various overloads of operator=
+(and other assigning operators) to allow selective replacement (slicing) of
+the controlled sequence. The selected elements must exist.
 
    
-
 
    
-24.2 [iterator.concepts] says that the only operation that can be performed on "singular"
-iterator values is to assign a non-singular value to them.  (It 
-doesn't say they can be destroyed, and that's probably a defect.)  
-Some implementations have taken this to imply that there is no need 
-to initialize the data member of a reverse_iterator<> in the default
-constructor.  As a result, code like
+The first member operator selects element off. For example:
 
    
-
      std::vector<std::reverse_iterator<char*> > v(7);
-  v.reserve(1000);
+
+
    valarray<char> v0("abcdefghijklmnop", 16);
+v0[3] = 'A';
+// v0 == valarray<char>("abcAefghijklmnop", 16)
 
    
-
    
-invokes undefined behavior, because it must default-initialize the
-vector elements, and then copy them to other storage.  Of course many 
-other vector operations on these adapters are also left undefined,
-and which those are is not reliably deducible from the standard.
-
    
 
 
    
-I don't think that 24.1 was meant to make standard-library iterator 
-types unsafe.  Rather, it was meant to restrict what operations may 
-be performed by functions which take general user- and standard 
-iterators as arguments, so that raw pointers would qualify as
-iterators.  However, this is not clear in the text, others have come 
-to the opposite conclusion.
+The second member operator selects those elements of the controlled sequence
+designated by slicearr. For example:
 
    
 
-
    
-One question is whether the standard iterator adaptors have defined
-copy semantics.  Another is whether they have defined destructor
-semantics: is
-
    
-
      { std::vector<std::reverse_iterator<char*> >  v(7); }
+
    valarray<char> v0("abcdefghijklmnop", 16);
+valarray<char> v1("ABCDE", 5);
+v0[slice(2, 5, 3)] = v1;
+// v0 == valarray<char>("abAdeBghCjkDmnEp", 16)
 
    
-
    
-undefined too?
-
    
 
 
    
-Note this is not a question of whether algorithms are allowed to
-rely on copy semantics for arbitrary iterators, just whether the
-types we actually supply support those operations.  I believe the 
-resolution must be expressed in terms of the semantics of the 
-adapter's argument type.  It should make clear that, e.g., the 
-reverse_iterator<T> constructor is actually required to execute
-T(), and so copying is defined if the result of T() is copyable.
+The third member operator selects those elements of the controlled sequence
+designated by gslicearr. For example:
 
    
 
-
    
-Issue 235, which defines reverse_iterator's default
-constructor more precisely, has some relevance to this issue.
-However, it is not the whole story.
-
    
+
    valarray<char> v0("abcdefghijklmnop", 16);
+valarray<char> v1("ABCDEF", 6);
+const size_t lv[] = {2, 3};
+const size_t dv[] = {7, 2};
+const valarray<size_t> len(lv, 2), str(dv, 2);
+v0[gslice(3, len, str)] = v1;
+// v0 == valarray<char>("abcAeBgCijDlEnFp", 16)
+
    
 
 
    
-The issue was whether 
+The fourth member operator selects those elements of the controlled sequence
+designated by boolarr. For example:
 
    
-
      reverse_iterator() { }
+
+
    valarray<char> v0("abcdefghijklmnop", 16);
+valarray<char> v1("ABC", 3);
+const bool vb[] = {false, false, true, true, false, true};
+v0[valarray<bool>(vb, 6)] = v1;
+// v0 == valarray<char>("abABeCghijklmnop", 16)
 
    
+
 
    
-is allowed, vs. 
+The fifth member operator selects those elements of the controlled sequence
+designated by indarr. For example:
 
    
-
      reverse_iterator() : current() { }
+
+
    valarray<char> v0("abcdefghijklmnop", 16);
+valarray<char> v1("ABCDE", 5);
+const size_t vi[] = {7, 5, 2, 3, 8};
+v0[valarray<size_t>(vi, 5)] = v1;
+// v0 == valarray<char>("abCDeBgAEjklmnop", 16)
 
    
 
 
    
-The difference is when T is char*, where the first leaves the member
-uninitialized, and possibly equal to an existing pointer value, or
-(on some targets) may result in a hardware trap when copied.
+The second group of five member operators each construct an object that
+represents the value(s) selected. The selected elements must exist.
 
    
 
 
    
-8.5 paragraph 5 seems to make clear that the second is required to
-satisfy DR 235, at least for non-class Iterator argument
-types.
+The sixth member operator returns the value of element off. For example:
 
    
 
-
    
-But that only takes care of reverse_iterator, and doesn't establish
-a policy for all iterators.  (The reverse iterator adapter was just
-an example.)  In particular, does my function
-
    
-
      template <typename Iterator>
-    void f() { std::vector<Iterator>  v(7); } 
+
    valarray<char> v0("abcdefghijklmnop", 16);
+// v0[3] returns 'd'
 
    
-
    
-evoke undefined behavior for some conforming iterator definitions?
-I think it does, now, because vector<> will destroy those singular
-iterator values, and that's explicitly disallowed.
-
    
 
 
    
-24.1 shouldn't give blanket permission to copy all singular iterators,
-because then pointers wouldn't qualify as iterators.  However, it
-should allow copying of that subset of singular iterator values that
-are default-initialized, and it should explicitly allow destroying any
-iterator value, singular or not, default-initialized or not.
+The seventh member operator returns an object of class valarray<Ty>
+containing those elements of the controlled sequence designated by slicearr.
+For example:
 
    
 
-
    Related issues: 407, 1012
    
-
    [
-We don't want to require all singular iterators to be copyable,
-because that is not the case for pointers.  However, default
-construction may be a special case.  Issue: is it really default
-construction we want to talk about, or is it something like value
-initialization?  We need to check with core to see whether default
-constructed pointers are required to be copyable; if not, it would be
-wrong to impose so strict a requirement for iterators.
-]
    
-
-
-
    [
-2009-05-10 Alisdair provided wording.
-]
    
-
-
-
    
-The comments regarding destroying singular iterators have already been
-resolved.  That just leaves copying (with moving implied).
-
    
-
-
+
    valarray<char> v0("abcdefghijklmnop", 16);
+// v0[slice(2, 5, 3)] returns valarray<char>("cfilo", 5)
+
    
 
-
    Proposed resolution:
    
 
    
-Add to the end of Iterator concepts 24.2 [iterator.concepts] para 6 (the one
-describing singular iterators)
+The eighth member operator selects those elements of the controlled sequence
+designated by gslicearr. For example:
 
    
-
    
-Any Iterator that satisfies the DefaultConstructible concept shall
-be safely copyable after value-initialization, even if it would otherwise be
-singular. [Note: This guarantee is not offered for default-initialization
-(8.5 [dcl.init]), although the distinction only matters for types with
-trivial default constructors such as pointers. — end note]
-
    
-
-
 
+
    valarray<char> v0("abcdefghijklmnop", 16);
+const size_t lv[] = {2, 3};
+const size_t dv[] = {7, 2};
+const valarray<size_t> len(lv, 2), str(dv, 2);
+// v0[gslice(3, len, str)] returns
+//    valarray<char>("dfhkmo", 6)
+
    
 
+
    
+The ninth member operator selects those elements of the controlled sequence
+designated by boolarr. For example:
+
    
 
+
    valarray<char> v0("abcdefghijklmnop", 16);
+const bool vb[] = {false, false, true, true, false, true};
+// v0[valarray<bool>(vb, 6)] returns
+//    valarray<char>("cdf", 3)
+
    
 
-
    
-
    417. what does ctype::do_widen() return on failure
    
-
    Section: 22.4.1.1.2 [locale.ctype.virtuals] Status: Open
- Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2006-12-27
    
-
    View all other issues in [locale.ctype.virtuals].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
 
    
-The Effects and Returns clauses of the do_widen() member function of
-the ctype facet fail to specify the behavior of the function on failure.
-That the function may not be able to simply cast the narrow character
-argument to the type of the result since doing so may yield the wrong value
-for some wchar_t encodings. Popular implementations of ctype<wchar_t> that
-use mbtowc() and UTF-8 as the native encoding (e.g., GNU glibc) will fail
-when the argument's MSB is set. There is no way for the the rest of locale
-and iostream to reliably detect this failure. 
+The last member operator selects those elements of the controlled sequence
+designated by indarr. For example:
 
    
-
    [Kona: This is a real problem.  Widening can fail.  It's unclear
-  what the solution should be.  Returning WEOF works for the wchar_t
-  specialization, but not in general.  One option might be to add a
-  default, like narrow.  But that's an incompatible change.
-  Using traits::eof might seem like a good idea, but facets
-  don't have access to traits (a recurring problem).  We could
-  have widen throw an exception, but that's a scary option;
-  existing library components aren't written with the assumption
-  that widen can throw.]
    
 
+
    valarray<char> v0("abcdefghijklmnop", 16);
+const size_t vi[] = {7, 5, 2, 3, 8};
+// v0[valarray<size_t>(vi, 5)] returns
+//    valarray<char>("hfcdi", 5)
+
    
 
+
    
 
-
    Proposed resolution:
    
 
 
 
 
 
    
-
    418. exceptions thrown during iostream cleanup
    
-
    Section: 27.5.2.1.6 [ios::Init] Status: Open
- Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2007-07-25
    
-
    View other active issues in [ios::Init].
    
-
    View all other issues in [ios::Init].
    
+
    431. Swapping containers with unequal allocators
    
+
    Section: X [allocator.requirements], 25 [algorithms] Status: Open
+ Submitter: Matt Austern Opened: 2003-09-20  Last modified: 2009-07-17
    
+
    View other active issues in [allocator.requirements].
    
+
    View all other issues in [allocator.requirements].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
-
    
-The dtor of the ios_base::Init object is supposed to call flush() on the
-6 standard iostream objects cout, cerr, clog, wcout, wcerr, and wclog.
-This call may cause an exception to be thrown.
-
    
-
-
    
-17.4.4.8, p3 prohibits all library destructors from throwing exceptions.
-
    
-
-
    
-The question is: What should this dtor do if one or more of these calls
-to flush() ends up throwing an exception? This can happen quite easily
-if one of the facets installed in the locale imbued in the iostream
-object throws.
+
    Clause X [allocator.requirements] paragraph 4 says that implementations
+  are permitted to supply containers that are unable to cope with
+  allocator instances and that container implementations may assume
+  that all instances of an allocator type compare equal.  We gave
+  implementers this latitude as a temporary hack, and eventually we
+  want to get rid of it.  What happens when we're dealing with
+  allocators that don't compare equal?
 
    
-
    [Kona: We probably can't do much better than what we've got, so
-  the LWG is leaning toward NAD.  At the point where the standard
-  stream objects are being cleaned up, the usual error reporting
-  mechanism are all unavailable.  And exception from flush at this
-  point will definitely cause problems.  A quality implementation
-  might reasonably swallow the exception, or call abort, or do
-  something even more drastic.]
    
-
-
-
    [
-See 397 and 622 for related issues.
-]
    
-
-
 
+
    In particular: suppose that v1 and v2 are both
+  objects of type vector<int, my_alloc> and that
+  v1.get_allocator() != v2.get_allocator().  What happens if
+  we write v1.swap(v2)?  Informally, three possibilities:
    
 
-
    Proposed resolution:
    
-
-
-
-
-
    
-
    419. istream extractors not setting failbit if eofbit is already set
    
-
    Section: 27.7.1.1.3 [istream::sentry] Status: Open
- Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2007-01-30
    
-
    View all other issues in [istream::sentry].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-        
    
-
-27.7.1.1.3 [istream::sentry], p2 says that istream::sentry ctor prepares for input if is.good()
-is true. p4 then goes on to say that the ctor sets the sentry::ok_ member to
-true if the stream state is good after any preparation. 27.7.1.2.1 [istream.formatted.reqmts], p1 then
-says that a formatted input function endeavors to obtain the requested input
-if the sentry's operator bool() returns true.
-
-Given these requirements, no formatted extractor should ever set failbit if
-the initial stream rdstate() == eofbit. That is contrary to the behavior of
-all implementations I tested. The program below prints out
-
-eof = 1, fail = 0
-eof = 1, fail = 1
-
-on all of them.
-        
    
-
    -#include <sstream>
-#include <cstdio>
+
    1. This operation is illegal.  Perhaps we could say that an
+  implementation is required to check and to throw an exception, or
+  perhaps we could say it's undefined behavior.
    
+
    2. The operation performs a slow swap (i.e. using three
+  invocations of operator=, leaving each allocator with its
+  original container.  This would be an O(N) operation.
    
+
    3. The operation swaps both the vectors' contents and their
+  allocators.  This would be an O(1) operation. That is:
    
+  
    
+  
        my_alloc a1(...);
+    my_alloc a2(...);
+    assert(a1 != a2);
 
-int main()
-{
-    std::istringstream strm ("1");
+    vector<int, my_alloc> v1(a1);
+    vector<int, my_alloc> v2(a2);
+    assert(a1 == v1.get_allocator());
+    assert(a2 == v2.get_allocator());
 
-    int i = 0;
+    v1.swap(v2);
+    assert(a1 == v2.get_allocator());
+    assert(a2 == v1.get_allocator());
+  
    
+  
    
 
-    strm >> i;
+
    [Kona: This is part of a general problem.  We need a paper
+  saying how to deal with unequal allocators in general.]
    
 
-    std::printf ("eof = %d, fail = %d\n",
-                 !!strm.eof (), !!strm.fail ());
 
-    strm >> i;
+
    [pre-Sydney: Howard argues for option 3 in
+N1599.
+]
    
 
-    std::printf ("eof = %d, fail = %d\n",
-                 !!strm.eof (), !!strm.fail ());
-}
 
-
    
-        
    
-
    
+
    [
+2007-01-12, Howard:  This issue will now tend to come up more often with move constructors
+and move assignment operators.  For containers, these members transfer resources (i.e.
+the allocated memory) just like swap.
+]
    
 
-Comments from Jerry Schwarz (c++std-lib-11373):
-
    
 
-Jerry Schwarz wrote:
-
    
+
    [
+Batavia:  There is agreement to overload the container swap on the allocator's Swappable
+requirement using concepts.  If the allocator supports Swappable, then container's swap will
+swap allocators, else it will perform a "slow swap" using copy construction and copy assignment.
+]
    
 
-I don't know where (if anywhere) it says it in the standard, but the
-formatted extractors are supposed to set failbit if they don't extract
-any characters. If they didn't then simple loops like
-
    
 
-while (cin >> x);
-
    
+
    [
+2009-04-28 Pablo adds:
+]
    
 
-would loop forever.
-
    
+
    
+Fixed in
+N2525.
+I argued for marking this Tentatively-Ready right after Bellevue,
+but there was a concern that
+N2525
+would break in the presence of the RVO. (That breakage had nothing to do with
+swap, but never-the-less). I addressed that breakage in in
+N2840
+(Summit) by means of a non-normative reference:
 
-Further comments from Martin Sebor:
-
    
+
    
+[Note: in situations where the copy constructor for a container is elided,
+this function is not called. The behavior in these cases is as if
+select_on_container_copy_construction returned x — end note]
+
    
 
-The question is which part of the extraction should prevent this from happening
-by setting failbit when eofbit is already set. It could either be the sentry
-object or the extractor. It seems that most implementations have chosen to
-set failbit in the sentry [...] so that's the text that will need to be
-corrected. 
+
    
 
-        
    
-
    
-Pre Berlin:  This issue is related to 342.  If the sentry
-sets failbit when it finds eofbit already set, then
-you can never seek away from the end of stream.
-
    
-
    Kona: Possibly NAD.  If eofbit is set then good() will return false.  We
-  then set ok to false.  We believe that the sentry's
-  constructor should always set failbit when ok is false, and
-  we also think the standard already says that.  Possibly it could be
-  clearer.
     
 
-    
 
 
    Proposed resolution:
    
-
    
-Change 27.7.1.1.3 [istream::sentry], p2 to:
-
    
-
-
    
-
    explicit sentry(basic_istream<charT,traits>& is , bool noskipws = false);
    
-
    
--2- Effects: If is.good() is true
-false, calls is.setstate(failbit). 
-Otherwise prepares for formatted or unformatted input. ...
-
    
-
    
-
 
 
 
 
 
 
    
-
    421. is basic_streambuf copy-constructible?
    
-
    Section: 27.6.2.1 [streambuf.cons] Status: Open
- Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2007-01-15
    
-
    View all other issues in [streambuf.cons].
    
+
    446. Iterator equality between different containers
    
+
    Section: 24.2 [iterator.concepts], 23.2 [container.requirements] Status: Open
+ Submitter: Andy Koenig Opened: 2003-12-16  Last modified: 2009-07-14
    
+
    View other active issues in [iterator.concepts].
    
+
    View all other issues in [iterator.concepts].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-The reflector thread starting with c++std-lib-11346 notes that the class
-template basic_streambuf, along with basic_stringbuf and basic_filebuf,
-is copy-constructible but that the semantics of the copy constructors
-are not defined anywhere. Further, different implementations behave
-differently in this respect: some prevent copy construction of objects
-of these types by declaring their copy ctors and assignment operators
-private, others exhibit undefined behavior, while others still give
-these operations well-defined semantics.
+What requirements does the standard place on equality comparisons between
+iterators that refer to elements of different containers.  For example, if
+v1 and v2 are empty vectors, is v1.end() == v2.end() allowed to yield true?
+Is it allowed to throw an exception?
 
    
 
 
    
-Note that this problem doesn't seem to be isolated to just the three
-types mentioned above. A number of other types in the library section
-of the standard provide a compiler-generated copy ctor and assignment
-operator yet fail to specify their semantics.  It's believed that the
-only types for which this is actually a problem (i.e. types where the
-compiler-generated default may be inappropriate and may not have been
-intended) are locale facets.  See issue 439.
+The standard appears to be silent on both questions.
 
    
+
    [Sydney: The intention is that comparing two iterators from
+different containers is undefined, but it's not clear if we say that,
+or even whether it's something we should be saying in clause 23 or in
+clause 24.  Intuitively we might want to say that equality is defined
+only if one iterator is reachable from another, but figuring out how
+to say it in any sensible way is a bit tricky: reachability is defined
+in terms of equality, so we can't also define equality in terms of
+reachability.
+]
    
 
 
-
    Proposed resolution:
    
-
    
-27.5.2 [lib.streambuf]:  Add into the synopsis, public section, just above the destructor declaration:
-
    
+
    [
+2009-07 Frankfurt
+]
    
 
-
    
-
    basic_streambuf(const basic_streambuf& sb);
-basic_streambuf& operator=(const basic_streambuf& sb);
-
    
-
    
 
-
    Insert after 27.5.2.1, paragraph 2:
    
 
    
-
    basic_streambuf(const basic_streambuf& sb);
-
    
-
-
    Constructs a copy of sb.
    
-
    Postcondtions:
    
-
                    eback() == sb.eback()
-                gptr()  == sb.gptr()
-                egptr() == sb.egptr()
-                pbase() == sb.pbase()
-                pptr()  == sb.pptr()
-                epptr() == sb.epptr()
-                getloc() == sb.getloc()
-
    
+Daniel volunteered to work on this.
+
    
 
-
    basic_streambuf& operator=(const basic_streambuf& sb);
-
    
 
-
    Assigns the data members of sb to this.
    
 
-
    Postcondtions:
    
-
                    eback() == sb.eback()
-                gptr()  == sb.gptr()
-                egptr() == sb.egptr()
-                pbase() == sb.pbase()
-                pptr()  == sb.pptr()
-                epptr() == sb.epptr()
-                getloc() == sb.getloc()
-
    
+
    Proposed resolution:
    
 
-
    Returns: *this.
    
-
    
 
-
    27.7.1 [lib.stringbuf]:
    
 
-
    Option A:
    
 
-
    
-
    Insert into the basic_stringbuf synopsis in the private section:
    
 
-
    basic_stringbuf(const basic_stringbuf&);             // not defined
-basic_stringbuf& operator=(const basic_stringbuf&);  // not defined
-
    
-
    
 
-
    Option B:
    
+
    
+
    458. 24.1.5 contains unintended limitation for operator-
    
+
    Section: 24.2.6 [random.access.iterators] Status: Open
+ Submitter: Daniel Frey Opened: 2004-02-27  Last modified: 2009-07-17
    
+
    View other active issues in [random.access.iterators].
    
+
    View all other issues in [random.access.iterators].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
+
    
+In 24.1.5 [lib.random.access.iterators], table 76 the operational
+semantics for the expression "r -= n" are defined as "return r += -n".
+This means, that the expression -n must be valid, which is not the case
+for unsigned types.
+
    
 
-
    
-
    Insert into the basic_stringbuf synopsis in the public section:
    
+
    [
+Sydney: Possibly not a real problem, since difference type is required
+to be a signed integer type. However, the wording in the standard may
+be less clear than we would like.
+]
    
 
-
    basic_stringbuf(const basic_stringbuf& sb);
-basic_stringbuf& operator=(const basic_stringbuf& sb);
-
    
 
-
    27.7.1.1, insert after paragraph 4:
    
+
    [
+Post Summit Alisdair adds:
+]
    
 
-
    basic_stringbuf(const basic_stringbuf& sb);
    
 
+
    
 
    
-Constructs an independent copy of sb as if with sb.str(), and with the openmode that sb was constructed with.
+This issue refers to a requirements table we have removed.
 
    
-
-
    Postcondtions: 
    
-
                   str() == sb.str()
-               gptr()  - eback() == sb.gptr()  - sb.eback()
-               egptr() - eback() == sb.egptr() - sb.eback()
-               pptr()  - pbase() == sb.pptr()  - sb.pbase()
-               getloc() == sb.getloc()
-
    
-
 
    
-Note: The only requirement on epptr() is that it point beyond the
-initialized range if an output sequence exists. There is no requirement
-that epptr() - pbase() == sb.epptr() - sb.pbase().
-
    
-
-
    basic_stringbuf& operator=(const basic_stringbuf& sb);
    
-
    After assignment the basic_stringbuf has the same state as if it
-were initially copy constructed from sb, except that the
-basic_stringbuf is allowed to retain any excess capacity it might have,
-which may in turn effect the value of epptr().
+The issue might now relate to 24.2.6 [random.access.iterators] p5.
+However, the rationale in the issue already recognises that the
+difference_type must be signed, so this really looks NAD.
 
    
 
    
 
-
    27.8.1.1 [lib.filebuf]
    
-
-
    Insert at the bottom of the basic_filebuf synopsis:
    
+
    [
+Batavia (2009-05):
+]
    
 
 
    
-
    private:
-  basic_filebuf(const basic_filebuf&);             // not defined
-  basic_filebuf& operator=(const basic_filebuf&);  // not defined
-
    
+
    
+We agree with Alisdair's observations.
+
    
+
    
+Move to NAD.
+
    
 
    
-
    [Kona: this is an issue for basic_streambuf itself and for its
-  derived classes.  We are leaning toward allowing basic_streambuf to
-  be copyable, and specifying its precise semantics.  (Probably the
-  obvious: copying the buffer pointers.)  We are less sure whether
-  the streambuf derived classes should be copyable.  Howard will
-  write up a proposal.]
    
-
-
-
    [Sydney: Dietmar presented a new argument against basic_streambuf
-  being copyable: it can lead to an encapsulation violation. Filebuf
-  inherits from streambuf. Now suppose you inhert a my_hijacking_buf
-  from streambuf. You can copy the streambuf portion of a filebuf to a
-  my_hijacking_buf, giving you access to the pointers into the
-  filebuf's internal buffer. Perhaps not a very strong argument, but
-  it was strong enough to make people nervous. There was weak
-  preference for having streambuf not be copyable. There was weak
-  preference for having stringbuf not be copyable even if streambuf
-  is. Move this issue to open for now.
-]
    
-
 
 
    [
-2007-01-12, Howard:
-Rvalue Reference Recommendations for Chapter 27
-recommends protected copy constructor and assignment for basic_streambuf with the same semantics
-as would be generated by the compiler.  These members aid in derived classes implementing move semantics.
-A protected copy constructor and copy assignment operator do not expose encapsulation more so than it is
-today as each data member of a basic_streambuf is already both readable and writable by derived
-classes via various get/set protected member functions (eback(), setp(), etc.).  Rather
-a protected copy constructor and copy assignment operator simply make the job of derived classes implementing
-move semantics less tedious and error prone.
+2009-07 Frankfurt:
 ]
    
 
 
-
-
-
    Rationale:
    
+
    
 
    
-27.5.2 [lib.streambuf]: The proposed basic_streambuf copy constructor
-and assignment operator are the same as currently implied by the lack
-of declarations: public and simply copies the data members.  This
-resolution is not a change but a clarification of the current
-standard.
+Need to look at again without concepts.
 
    
-
 
    
-27.7.1 [lib.stringbuf]: There are two reasonable options: A) Make
-basic_stringbuf not copyable.  This is likely the status-quo of
-current implementations.  B) Reasonable copy semantics of
-basic_stringbuf can be defined and implemented.  A copyable
-basic_streambuf is arguably more useful than a non-copyable one.  This
-should be considered as new functionality and not the fixing of a
-defect.  If option B is chosen, ramifications from issue 432 are taken
-into account.
+There was a question about this phrase in the discussion: "the
+expression -n must be valid, which is not the case for unsigned types."
+If n is an object ofthe iterator difference_type (eg ptrdiff_t), then it
+is never unsigned.
 
    
+
    
+
 
+
+
    Proposed resolution:
    
 
    
-27.8.1.1 [lib.filebuf]: There are no reasonable copy semantics for
-basic_filebuf.
+To remove this limitation, I suggest to change the
+operational semantics for this column to:
 
    
+
        { Distance m = n;
+      if (m >= 0)
+        while (m--) --r;
+      else
+        while (m++) ++r;
+      return r; }
+
    
 
 
 
@@ -3557,565 +2660,504 @@ basic_filebuf.
 
 
 
    
-
    423. effects of negative streamsize in iostreams
    
-
    Section: 27 [input.output] Status: Open
- Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2006-12-27
    
-
    View other active issues in [input.output].
    
-
    View all other issues in [input.output].
    
+
    463. auto_ptr usability issues
    
+
    Section: D.9.1 [auto.ptr] Status: Open
+ Submitter: Rani Sharoni Opened: 2003-12-07  Last modified: 2009-07-14
    
+
    View all other issues in [auto.ptr].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
 
    
-A third party test suite tries to exercise istream::ignore(N) with
-a negative value of N and expects that the implementation will treat
-N as if it were 0. Our implementation asserts that (N >= 0) holds and
-aborts the test.
+TC1 CWG DR #84 effectively made the template<class Y> operator auto_ptr<Y>()
+member of auto_ptr (20.4.5.3/4) obsolete.
 
    
 
 
    
-I can't find anything in section 27 that prohibits such values but I don't
-see what the effects of such calls should be, either (this applies to
-a number of unformatted input functions as well as some member functions
-of the basic_streambuf template).
+The sole purpose of this obsolete conversion member is to enable copy
+initialization base from r-value derived (or any convertible types like
+cv-types) case:
 
    
+
    #include <memory>
+using std::auto_ptr;
 
+struct B {};
+struct D : B {};
+
+auto_ptr<D> source();
+int sink(auto_ptr<B>);
+int x1 = sink( source() ); // #1 EDG - no suitable copy constructor
+
    
 
-
    Proposed resolution:
    
 
    
-I propose that we add to each function in clause 27 that takes an argument,
-say N, of type streamsize a Requires clause saying that "N >= 0." The intent
-is to allow negative streamsize values in calls to precision() and width()
-but disallow it in calls to streambuf::sgetn(), istream::ignore(), or
-ostream::write().
+The excellent analysis of conversion operations that was given in the final
+auto_ptr proposal
+(http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/1997/N1128.pdf)
+explicitly specifies this case analysis (case 4). DR #84 makes the analysis
+wrong and actually comes to forbid the loophole that was exploited by the
+auto_ptr designers.
 
    
 
-
    [Kona: The LWG agreed that this is probably what we want.  However, we
-  need a review to find all places where functions in clause 27 take
-  arguments of type streamsize that shouldn't be allowed to go
-  negative.  Martin will do that review.]
    
+
    
+I didn't encounter any compliant compiler (e.g. EDG, GCC, BCC and VC) that
+ever allowed this case. This is probably because it requires 3 user defined
+conversions and in fact current compilers conform to DR #84.
+
    
 
+
    
+I was surprised to discover that the obsolete conversion member actually has
+negative impact of the copy initialization base from l-value derived
+case:
    
+
    auto_ptr<D> dp;
+int x2 = sink(dp); // #2 EDG - more than one user-defined conversion applies
+
    
 
+
    
+I'm sure that the original intention was allowing this initialization using
+the template<class Y> auto_ptr(auto_ptr<Y>& a) constructor (20.4.5.1/4) but
+since in this copy initialization it's merely user defined conversion (UDC)
+and the obsolete conversion member is UDC with the same rank (for the early
+overloading stage) there is an ambiguity between them.
+
    
 
+
    
+Removing the obsolete member will have impact on code that explicitly
+invokes it:
+
    
+
    int y = sink(source().operator auto_ptr<B>());
+
    
 
+
    
+IMHO no one ever wrote such awkward code and the reasonable workaround for
+#1 is:
+
    
+
    int y = sink( auto_ptr<B>(source()) );
+
    
 
+
    
+I was even more surprised to find out that after removing the obsolete
+conversion member the initialization was still ill-formed:
+int x3 = sink(dp); // #3 EDG - no suitable copy constructor
+
    
 
-
    
-
    424. normative notes
    
-
    Section: 17.5.1.2 [structure.summary] Status: Tentatively NAD Editorial
- Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2009-05-23
    
-
    View all issues with Tentatively NAD Editorial status.
    
-
    Discussion:
    
+
    
+This copy initialization semantically requires copy constructor which means
+that both template conversion constructor and the auto_ptr_ref conversion
+member (20.4.5.3/3) are required which is what was explicitly forbidden in
+DR #84. This is a bit amusing case in which removing ambiguity results with
+no candidates.
+
    
 
 
    
-The text in 17.3.1.1, p1 says:
-
    
+I also found exception safety issue with auto_ptr related to auto_ptr_ref:
+
    
+
    int f(auto_ptr<B>, std::string);
+auto_ptr<B> source2();
 
-"Paragraphs labelled "Note(s):" or "Example(s):" are informative, other
-paragraphs are normative."
-
    
+// string constructor throws while auto_ptr_ref
+// "holds" the pointer
+int x4 = f(source2(), "xyz"); // #4
+
    
 
-The library section makes heavy use of paragraphs labeled "Notes(s),"
-some of which are clearly intended to be normative (see list 1), while
-some others are not (see list 2). There are also those where the intent
-is not so clear (see list 3).
-

    
+
    
+The theoretic execution sequence that will cause a leak:
+
    
+
      
+
    1. call auto_ptr<B>::operator auto_ptr_ref<B>()
      2. 
+
    2. call string::string(char const*) and throw
      3. 
+
    
 
-List 1 -- Examples of (presumably) normative Notes:
-
    
+
    
+According to 20.4.5.3/3 and 20.4.5/2 the auto_ptr_ref conversion member
+returns auto_ptr_ref<Y> that holds *this and this is another defect since
+the type of *this is auto_ptr<X> where X might be different from Y. Several
+library vendors (e.g. SGI) implement auto_ptr_ref<Y> with Y* as member which
+is much more reasonable. Other vendor implemented auto_ptr_ref as
+defectively required and it results with awkward and catastrophic code:
+int oops = sink(auto_ptr<B>(source())); // warning recursive on all control
+paths
+
    
 
-20.8.6.1 [allocator.members], p3,
    
-20.8.6.1 [allocator.members], p10,
    
-21.4.2 [string.cons], p11,
    
-22.3.1.2 [locale.cons], p11,
    
-23.3.2.3 [deque.modifiers], p2,
    
-25.5.7 [alg.min.max], p3,
    
-26.4.6 [complex.ops], p15,
    
-27.6.2.4.3 [streambuf.virt.get], p7.
    
-
    
+
    
+Dave Abrahams noticed that there is no specification saying that
+auto_ptr_ref copy constructor can't throw.
+
    
 
-List 2 -- Examples of (presumably) informative Notes:
-
    
+
    
+My proposal comes to solve all the above issues and significantly simplify
+auto_ptr implementation. One of the fundamental requirements from auto_ptr
+is that it can be constructed in an intuitive manner (i.e. like ordinary
+pointers) but with strict ownership semantics which yield that source
+auto_ptr in initialization must be non-const. My idea is to add additional
+constructor template with sole propose to generate ill-formed, diagnostic
+required, instance for const auto_ptr arguments during instantiation of
+declaration. This special constructor will not be instantiated for other
+types which is achievable using 14.8.2/2 (SFINAE). Having this constructor
+in hand makes the constructor template<class Y> auto_ptr(auto_ptr<Y> const&)
+legitimate since the actual argument can't be const yet non const r-value
+are acceptable.
+
    
 
-18.6.1.3 [new.delete.placement], p3,
    
-21.4.6.6 [string::replace], p14,
    
-22.4.1.4.2 [locale.codecvt.virtuals], p3,
    
-25.3.4 [alg.foreach], p4,
    
-26.4.5 [complex.member.ops], p1,
    
-27.5.2.5 [ios.base.storage], p6.
    
-
    
+
    
+This implementation technique makes the "private auxiliary class"
+auto_ptr_ref obsolete and I found out that modern C++ compilers (e.g. EDG,
+GCC and VC) consume the new implementation as expected and allow all
+intuitive initialization and assignment cases while rejecting illegal cases
+that involve const auto_ptr arguments.
+
    
 
-List 3 -- Examples of Notes that are not clearly either normative
-or informative:
-
    
+
    The proposed auto_ptr interface:
    
 
-22.3.1.2 [locale.cons], p8,
    
-22.3.1.5 [locale.statics], p6,
    
-27.6.2.4.5 [streambuf.virt.put], p4.
    
-
    
+
    namespace std {
+    template<class X> class auto_ptr {
+    public:
+        typedef X element_type;
+
+        // 20.4.5.1 construct/copy/destroy:
+        explicit auto_ptr(X* p=0) throw();
+        auto_ptr(auto_ptr&) throw();
+        template<class Y> auto_ptr(auto_ptr<Y> const&) throw();
+        auto_ptr& operator=(auto_ptr&) throw();
+        template<class Y> auto_ptr& operator=(auto_ptr<Y>) throw();
+        ~auto_ptr() throw();
+
+        // 20.4.5.2 members:
+        X& operator*() const throw();
+        X* operator->() const throw();
+        X* get() const throw();
+        X* release() throw();
+        void reset(X* p=0) throw();
+
+    private:
+        template<class U>
+        auto_ptr(U& rhs, typename
+unspecified_error_on_const_auto_ptr<U>::type = 0);
+    };
+}
+
    
 
-None of these lists is meant to be exhaustive.
+
    
+One compliant technique to implement the unspecified_error_on_const_auto_ptr
+helper class is using additional private auto_ptr member class template like
+the following:
 
    
+
    template<typename T> struct unspecified_error_on_const_auto_ptr;
 
-
    [Definitely a real problem.  The big problem is there's material
-  that doesn't quite fit any of the named paragraph categories
-  (e.g. Effects).  Either we need a new kind of named
-  paragraph, or we need to put more material in unnamed paragraphs
-  jsut after the signature.  We need to talk to the Project Editor
-  about how to do this.
-]
    
+template<typename T>
+struct unspecified_error_on_const_auto_ptr<auto_ptr<T> const>
+{ typedef typename auto_ptr<T>::const_auto_ptr_is_not_allowed type; };
+
    
+
+
    
+There are other techniques to implement this helper class that might work
+better for different compliers (i.e. better diagnostics) and therefore I
+suggest defining its semantic behavior without mandating any specific
+implementation. IMO, and I didn't found any compiler that thinks otherwise,
+14.7.1/5 doesn't theoretically defeat the suggested technique but I suggest
+verifying this with core language experts.
+
    
 
+
    Further changes in standard text:
    
+
    Remove section 20.4.5.3
    
 
-
    [
-Bellevue: Specifics of list 3: First 2 items correct in std (22.1.1.2,
-22.1.1.5) Third item should be non-normative (27.5.2.4.5), which Pete
-will handle editorially.
-]
    
+
    Change 20.4.5/2 to read something like:
+Initializing auto_ptr<X> from const auto_ptr<Y> will result with unspecified
+ill-formed declaration that will require unspecified diagnostic.
    
 
+
    Change 20.4.5.1/4,5,6 to read:
    
 
-
    [
-post San Francisco:  Howard: reopened, needs attention.
-]
    
+
    template<class Y> auto_ptr(auto_ptr<Y> const& a) throw();
    
+
     4 Requires: Y* can be implicitly converted to X*.
    
+
     5 Effects: Calls const_cast<auto_ptr<Y>&>(a).release().
    
+
     6 Postconditions: *this holds the pointer returned from a.release().
    
+
+
    Change 20.4.5.1/10
    
+
    template<class Y> auto_ptr& operator=(auto_ptr<Y> a) throw();
+
    
+
    
+10 Requires: Y* can be implicitly converted to X*. The expression delete
+get() is well formed.
+
    
+
+
    LWG TC DR #127 is obsolete.
    
+
+
    
+Notice that the copy constructor and copy assignment operator should remain
+as before and accept non-const auto_ptr& since they have effect on the form
+of the implicitly declared copy constructor and copy assignment operator of
+class that contains auto_ptr as member per 12.8/5,10:
+
    
+
    struct X {
+    // implicit X(X&)
+    // implicit X& operator=(X&)
+    auto_ptr<D> aptr_;
+};
+
    
+
+
    
+In most cases this indicates about sloppy programming but preserves the
+current auto_ptr behavior.
+
    
+
+
    
+Dave Abrahams encouraged me to suggest fallback implementation in case that
+my suggestion that involves removing of auto_ptr_ref will not be accepted.
+In this case removing the obsolete conversion member to auto_ptr<Y> and
+20.4.5.3/4,5 is still required in order to eliminate ambiguity in legal
+cases. The two constructors that I suggested will co exist with the current
+members but will make auto_ptr_ref obsolete in initialization contexts.
+auto_ptr_ref will be effective in assignment contexts as suggested in DR
+#127 and I can't see any serious exception safety issues in those cases
+(although it's possible to synthesize such). auto_ptr_ref<X> semantics will
+have to be revised to say that it strictly holds pointer of type X and not
+reference to an auto_ptr for the favor of cases in which auto_ptr_ref<Y> is
+constructed from auto_ptr<X> in which X is different from Y (i.e. assignment
+from r-value derived to base).
+
    
+
+
    [Redmond: punt for the moment. We haven't decided yet whether we
+  want to fix auto_ptr for C++-0x, or remove it and replace it with
+  move_ptr and unique_ptr.]
    
 
 
-
    [Pete: I changed the paragraphs marked "Note" and "Notes" to use "Remark" and "Remarks".
-Fixed as editorial.  This change has been in the WD since the post-Redmond mailing, in 2004.
-Recommend NAD.]
    
+
    [
+Oxford 2007: Recommend NAD.  We're just going to deprecate it.  It still works for simple use cases
+and people know how to deal with it.  Going forward unique_ptr is the recommended
+tool.
+]
    
 
 
 
    [
-Batavia:  We feel that the references in List 2 above should be changed from Remarks
-to Notes.  We also feel that those items in List 3 need to be double checked for
-the same change.  Alan and Pete to review.
+2007-11-09: Reopened at the request of David Abrahams, Alisdair Meredith and Gabriel Dos Reis.
 ]
    
 
 
 
    [
-Batavia (2009-05):
+2009-07 Frankfurt
 ]
    
 
+
 
    
-
    
-A spot-check of List 2 suggests the issue is still relevant,
-and a review of List 3 still seems called-for.
-
    
-
    
-Move to NAD Editorial.
-
    
+This is a complicated issue, so we agreed to defer discussion until
+later in the week so that interested parties can read up on it.
 
    
 
 
 
 
    Proposed resolution:
    
+
    
+Change the synopsis in D.9.1 [auto.ptr]:
+
    
 
+
    namespace std { 
+  template <class Y> struct auto_ptr_ref {};
 
+  // exposition only
+  template <class T> struct constant_object;
 
+  // exposition only
+  template <class T>
+  struct cannot_transfer_ownership_from
+    : constant_object<T> {};
 
-
    
-
    427. stage 2 and rationale of DR 221
    
-
    Section: 22.4.2.1.2 [facet.num.get.virtuals] Status: Open
- Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2007-01-15
    
-
    View other active issues in [facet.num.get.virtuals].
    
-
    View all other issues in [facet.num.get.virtuals].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    
-The requirements specified in Stage 2 and reiterated in the rationale
-of DR 221 (and echoed again in DR 303) specify that num_get<charT>::
-do_get() compares characters on the stream against the widened elements
-of "012...abc...ABCX+-"
-
    
-
-
    
-An implementation is required to allow programs to instantiate the num_get
-template on any charT that satisfies the requirements on a user-defined
-character type. These requirements do not include the ability of the
-character type to be equality comparable (the char_traits template must
-be used to perform tests for equality). Hence, the num_get template cannot
-be implemented to support any arbitrary character type. The num_get template
-must either make the assumption that the character type is equality-comparable
-(as some popular implementations do), or it may use char_traits<charT> to do
-the comparisons (some other popular implementations do that). This diversity
-of approaches makes it difficult to write portable programs that attempt to
-instantiate the num_get template on user-defined types.
-
    
-
-
    [Kona: the heart of the problem is that we're theoretically
-  supposed to use traits classes for all fundamental character
-  operations like assignment and comparison, but facets don't have
-  traits parameters.  This is a fundamental design flaw and it
-  appears all over the place, not just in this one place.  It's not
-  clear what the correct solution is, but a thorough review of facets
-  and traits is in order.  The LWG considered and rejected the
-  possibility of changing numeric facets to use narrowing instead of
-  widening.  This may be a good idea for other reasons (see issue
-  459), but it doesn't solve the problem raised by this
-  issue.  Whether we use widen or narrow the num_get facet
-  still has no idea which traits class the user wants to use for 
-  the comparison, because only streams, not facets, are passed traits
-  classes.   The standard does not require that two different
-  traits classes with the same char_type must necessarily 
-  have the same behavior.]
    
-
+  template <class X> class auto_ptr { 
+  public: 
+    typedef X element_type; 
 
-
    Informally, one possibility: require that some of the basic
-character operations, such as eq, lt,
-and assign, must behave the same way for all traits classes
-with the same char_type.  If we accept that limitation on
-traits classes, then the facet could reasonably be required to
-use char_traits<charT>.
    
+    // D.9.1.1 construct/copy/destroy: 
+    explicit auto_ptr(X* p =0) throw(); 
+    auto_ptr(auto_ptr&) throw(); 
+    template<class Y> auto_ptr(auto_ptr<Y> const&) throw(); 
+    auto_ptr& operator=(auto_ptr&) throw(); 
+    template<class Y> auto_ptr& operator=(auto_ptr<Y>&) throw();
+    auto_ptr& operator=(auto_ptr_ref<X> r) throw();
+    ~auto_ptr() throw(); 
 
+    // D.9.1.2 members: 
+    X& operator*() const throw();
+    X* operator->() const throw();
+    X* get() const throw();
+    X* release() throw();
+    void reset(X* p =0) throw();
 
-
    Proposed resolution:
    
+    // D.9.1.3 conversions:
+    auto_ptr(auto_ptr_ref<X>) throw();
+    template<class Y> operator auto_ptr_ref<Y>() throw();
+    template<class Y> operator auto_ptr<Y>() throw();
 
+    // exposition only
+    template<class U>
+    auto_ptr(U& rhs, typename cannot_transfer_ownership_from<U>::error = 0);
+  }; 
 
+  template <> class auto_ptr<void> 
+  { 
+  public: 
+    typedef void element_type; 
+  }; 
 
+}
+
    
 
-
    
-
    430. valarray subset operations
    
-
    Section: 26.6.2.4 [valarray.sub] Status: Open
- Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2009-05-01
    
-
    View all issues with Open status.
    
-
    Discussion:
    
 
    
-The standard fails to specify the behavior of valarray::operator[](slice)
-and other valarray subset operations when they are passed an "invalid"
-slice object, i.e., either a slice that doesn't make sense at all (e.g.,
-slice (0, 1, 0) or one that doesn't specify a valid subset of the valarray
-object (e.g., slice (2, 1, 1) for a valarray of size 1).
+Remove D.9.1.3 [auto.ptr.conv].
 
    
-
    [Kona: the LWG believes that invalid slices should invoke
-  undefined behavior.  Valarrays are supposed to be designed for high
-  performance, so we don't want to require specific checking.  We
-  need wording to express this decision.]
    
-
-
-
    [
-Bellevue:
-]
    
 
+
    
+Change D.9.1 [auto.ptr], p3:
+
    
 
 
    
-Please note that the standard also fails to specify the behavior of
-slice_array and gslice_array in the valid case. Bill Plauger will
-endeavor to provide revised wording for slice_array and gslice_array.
+The auto_ptr provides a semantics of strict ownership. An
+auto_ptr owns the object it holds a pointer to. Copying an
+auto_ptr copies the pointer and transfers ownership to the
+destination. If more than one auto_ptr owns the same object at
+the same time the behavior of the program is undefined. Templates
+constant_object and cannot_transfer_ownership_from,
+and the final constructor of auto_ptr are for exposition only.
+For any types X and Y, initializing
+auto_ptr<X> from const auto_ptr<Y> is
+ill-formed, diagnostic required. [Note: The uses of
+auto_ptr include providing temporary exception-safety for
+dynamically allocated memory, passing ownership of dynamically allocated
+memory to a function, and returning dynamically allocated memory from a
+function. auto_ptr does not meet the CopyConstructible
+and Assignable requirements for Standard Library container
+elements and thus instantiating a Standard Library container with an
+auto_ptr results in undefined behavior. -- end note]
 
    
 
-
    [
-post-Bellevue:  Bill provided wording.
-]
    
-
-
-
-
    Proposed resolution:
    
 
    
-Insert after 26.6.2.4 [valarray.sub], paragraph 1:
+Change D.9.1.1 [auto.ptr.cons], p5:
 
    
 
 
    
+
    template<class Y> auto_ptr(auto_ptr<Y> const& a) throw();
+
    
+
    
 
    
-The member operator is overloaded to provide several ways to select
-sequences
-of elements from among those controlled by *this. The first group of five
-member operators work in conjunction with various overloads of operator=
-(and other assigning operators) to allow selective replacement (slicing) of
-the controlled sequence. The selected elements must exist.
+Requires: Y* can be implicitly converted to X*.
 
    
 
    
-The first member operator selects element off. For example:
+Effects: Calls const_cast<auto_ptr<Y>&>(a).release().
 
    
-
-
    valarray<char> v0("abcdefghijklmnop", 16);
-v0[3] = 'A';
-// v0 == valarray<char>("abcAefghijklmnop", 16)
-
    
-
 
    
-The second member operator selects those elements of the controlled sequence
-designated by slicearr. For example:
+Postconditions: *this holds the pointer returned from a.release().
 
    
-
-
    valarray<char> v0("abcdefghijklmnop", 16);
-valarray<char> v1("ABCDE", 5);
-v0[slice(2, 5, 3)] = v1;
-// v0 == valarray<char>("abAdeBghCjkDmnEp", 16)
-
    
+
    
+
    
 
 
    
-The third member operator selects those elements of the controlled sequence
-designated by gslicearr. For example:
+Change D.9.1.1 [auto.ptr.cons], p10:
 
    
 
-
    valarray<char> v0("abcdefghijklmnop", 16);
-valarray<char> v1("ABCDEF", 6);
-const size_t lv[] = {2, 3};
-const size_t dv[] = {7, 2};
-const valarray<size_t> len(lv, 2), str(dv, 2);
-v0[gslice(3, len, str)] = v1;
-// v0 == valarray<char>("abcAeBgCijDlEnFp", 16)
-
    
-
+
    
+
    template<class Y> auto_ptr& operator=(auto_ptr<Y>& a) throw();
+
    
+
    
 
    
-The fourth member operator selects those elements of the controlled sequence
-designated by boolarr. For example:
+Requires: Y* can be implicitly converted to X*.
+The expression delete get() is well formed.
 
    
-
-
    valarray<char> v0("abcdefghijklmnop", 16);
-valarray<char> v1("ABC", 3);
-const bool vb[] = {false, false, true, true, false, true};
-v0[valarray<bool>(vb, 6)] = v1;
-// v0 == valarray<char>("abABeCghijklmnop", 16)
-
    
-
 
    
-The fifth member operator selects those elements of the controlled sequence
-designated by indarr. For example:
+Effects: Calls reset(a.release()).
 
    
-
-
    valarray<char> v0("abcdefghijklmnop", 16);
-valarray<char> v1("ABCDE", 5);
-const size_t vi[] = {7, 5, 2, 3, 8};
-v0[valarray<size_t>(vi, 5)] = v1;
-// v0 == valarray<char>("abCDeBgAEjklmnop", 16)
-
    
-
 
    
-The second group of five member operators each construct an object that
-represents the value(s) selected. The selected elements must exist.
+Returns: *this.
 
    
+
    
+
    
 
-
    
-The sixth member operator returns the value of element off. For example:
-
    
 
-
    valarray<char> v0("abcdefghijklmnop", 16);
-// v0[3] returns 'd'
-
    
 
-
    
-The seventh member operator returns an object of class valarray<Ty>
-containing those elements of the controlled sequence designated by slicearr.
-For example:
-
    
 
-
    valarray<char> v0("abcdefghijklmnop", 16);
-// v0[slice(2, 5, 3)] returns valarray<char>("cfilo", 5)
-
    
 
-
    
-The eighth member operator selects those elements of the controlled sequence
-designated by gslicearr. For example:
-
    
 
-
    valarray<char> v0("abcdefghijklmnop", 16);
-const size_t lv[] = {2, 3};
-const size_t dv[] = {7, 2};
-const valarray<size_t> len(lv, 2), str(dv, 2);
-// v0[gslice(3, len, str)] returns
-//    valarray<char>("dfhkmo", 6)
-
    
+
    
+
    471. result of what() implementation-defined
    
+
    Section: 18.8.1 [exception] Status: Open
+ Submitter: Martin Sebor Opened: 2004-06-28  Last modified: 2009-07-30
    
+
    View all issues with Open status.
    
+
    Discussion:
    
+
+
    [lib.exception] specifies the following:
    
+
        exception (const exception&) throw();
+    exception& operator= (const exception&) throw();
+
+    -4- Effects: Copies an exception object.
+    -5- Notes: The effects of calling what() after assignment
+        are implementation-defined.
+
    
 
 
    
-The ninth member operator selects those elements of the controlled sequence
-designated by boolarr. For example:
+First, does the Note only apply to the assignment operator? If so,
+what are the effects of calling what() on a copy of an object? Is
+the returned pointer supposed to point to an identical copy of
+the NTBS returned by what() called on the original object or not?
 
    
 
-
    valarray<char> v0("abcdefghijklmnop", 16);
-const bool vb[] = {false, false, true, true, false, true};
-// v0[valarray<bool>(vb, 6)] returns
-//    valarray<char>("cdf", 3)
-
    
-
 
    
-The last member operator selects those elements of the controlled sequence
-designated by indarr. For example:
+Second, is this Note intended to extend to all the derived classes
+in section 19? I.e., does the standard provide any guarantee for
+the effects of what() called on a copy of any of the derived class
+described in section 19?
 
    
 
-
    valarray<char> v0("abcdefghijklmnop", 16);
-const size_t vi[] = {7, 5, 2, 3, 8};
-// v0[valarray<size_t>(vi, 5)] returns
-//    valarray<char>("hfcdi", 5)
-
    
-
-
    
-
-
-
-
-
-
    
-
    431. Swapping containers with unequal allocators
    
-
    Section: X [allocator.requirements], 25 [algorithms] Status: Open
- Submitter: Matt Austern Opened: 2003-09-20  Last modified: 2009-05-01
    
-
    View other active issues in [allocator.requirements].
    
-
    View all other issues in [allocator.requirements].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    Clause X [allocator.requirements] paragraph 4 says that implementations
-  are permitted to supply containers that are unable to cope with
-  allocator instances and that container implementations may assume
-  that all instances of an allocator type compare equal.  We gave
-  implementers this latitude as a temporary hack, and eventually we
-  want to get rid of it.  What happens when we're dealing with
-  allocators that don't compare equal?
+
    
+Finally, if the answer to the first question is no, I believe it
+constitutes a defect since throwing an exception object typically
+implies invoking the copy ctor on the object. If the answer is yes,
+then I believe the standard ought to be clarified to spell out
+exactly what the effects are on the copy (i.e., after the copy
+ctor was called).
 
    
 
-
    In particular: suppose that v1 and v2 are both
-  objects of type vector<int, my_alloc> and that
-  v1.get_allocator() != v2.get_allocator().  What happens if
-  we write v1.swap(v2)?  Informally, three possibilities:
    
-
-
    1. This operation is illegal.  Perhaps we could say that an
-  implementation is required to check and to throw an exception, or
-  perhaps we could say it's undefined behavior.
    
-
    2. The operation performs a slow swap (i.e. using three
-  invocations of operator=, leaving each allocator with its
-  original container.  This would be an O(N) operation.
    
-
    3. The operation swaps both the vectors' contents and their
-  allocators.  This would be an O(1) operation. That is:
    
-  
    
-  
        my_alloc a1(...);
-    my_alloc a2(...);
-    assert(a1 != a2);
-
-    vector<int, my_alloc> v1(a1);
-    vector<int, my_alloc> v2(a2);
-    assert(a1 == v1.get_allocator());
-    assert(a2 == v2.get_allocator());
-
-    v1.swap(v2);
-    assert(a1 == v2.get_allocator());
-    assert(a2 == v1.get_allocator());
-  
    
-  
    
-
-
    [Kona: This is part of a general problem.  We need a paper
-  saying how to deal with unequal allocators in general.]
    
-
-
-
    [pre-Sydney: Howard argues for option 3 in
-N1599.
-]
    
-
-
-
    [
-2007-01-12, Howard:  This issue will now tend to come up more often with move constructors
-and move assignment operators.  For containers, these members transfer resources (i.e.
-the allocated memory) just like swap.
-]
    
+
    [Redmond: Yes, this is fuzzy.  The issue of derived classes is
+  fuzzy too.]
    
 
 
 
    [
-Batavia:  There is agreement to overload the container swap on the allocator's Swappable
-requirement using concepts.  If the allocator supports Swappable, then container's swap will
-swap allocators, else it will perform a "slow swap" using copy construction and copy assignment.
+Batavia: Howard provided wording.
 ]
    
 
 
 
    [
-2009-04-28 Pablo adds:
+Bellevue:
 ]
    
 
-
    
-Fixed in
-N2525.
-I argued for marking this Tentatively-Ready right after Bellevue,
-but there was a concern that
-N2525
-would break in the presence of the RVO. (That breakage had nothing to do with
-swap, but never-the-less). I addressed that breakage in in
-N2840
-(Summit) my means of a non-normative reference:
 
 
    
-[Note: in situations where the copy constructor for a container is elided,
-this function is not called. The behavior in these cases is as if
-select_on_container_copy_construction returned x — end note]
-
    
-
-
    
-
-
-
-
    Proposed resolution:
    
-
-
-
-
-
-
    
-
    446. Iterator equality between different containers
    
-
    Section: 24.2 [iterator.concepts], 23.2 [container.requirements] Status: Open
- Submitter: Andy Koenig Opened: 2003-12-16  Last modified: 2008-09-30
    
-
    View other active issues in [iterator.concepts].
    
-
    View all other issues in [iterator.concepts].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
 
    
-What requirements does the standard place on equality comparisons between
-iterators that refer to elements of different containers.  For example, if
-v1 and v2 are empty vectors, is v1.end() == v2.end() allowed to yield true?
-Is it allowed to throw an exception?
+Eric concerned this is unimplementable, due to nothrow guarantees.
+Suggested implementation would involve reference counting.
 
    
-
 
    
-The standard appears to be silent on both questions.
+Is the implied reference counting subtle enough to call out a note on
+implementation? Probably not.
 
    
-
    [Sydney: The intention is that comparing two iterators from
-different containers is undefined, but it's not clear if we say that,
-or even whether it's something we should be saying in clause 23 or in
-clause 24.  Intuitively we might want to say that equality is defined
-only if one iterator is reachable from another, but figuring out how
-to say it in any sensible way is a bit tricky: reachability is defined
-in terms of equality, so we can't also define equality in terms of
-reachability.
-]
    
-
-
-
-
-
    Proposed resolution:
    
-
-
-
-
-
-
-
    
-
    458. 24.1.5 contains unintented limitation for operator-
    
-
    Section: 24.2.6 [random.access.iterators] Status: Tentatively NAD
- Submitter: Daniel Frey Opened: 2004-02-27  Last modified: 2009-05-23
    
-
    View other active issues in [random.access.iterators].
    
-
    View all other issues in [random.access.iterators].
    
-
    View all issues with Tentatively NAD status.
    
-
    Discussion:
    
 
    
-In 24.1.5 [lib.random.access.iterators], table 76 the operational
-semantics for the expression "r -= n" are defined as "return r += -n".
-This means, that the expression -n must be valid, which is not the case
-for unsigned types.
+If reference counting required, could we tighten specification further
+to require same pointer value? Probably an overspecification, especially
+if exception classes defer evalutation of final string to calls to
+what().
 
    
+
    
+Remember issue moved open and not resolved at Batavia, but cannot
+remember who objected to canvas a disenting opinion - please speak up if
+you disagree while reading these minutes!
+
    
+
    
+Move to Ready as we are accepting words unmodified.
+
    
+
    
 
 
    [
-Sydney: Possibly not a real problem, since difference type is required
-to be a signed integer type. However, the wording in the standard may
-be less clear than we would like.
-]
    
-
-
-
    [
-Post Summit Alisdair adds:
+Sophia Antipolis:
 ]
    
 
 
 
    
-
    
-This issue refers to a requirements table we have removed.
-
    
-
    
-The issue might now relate to 24.2.6 [random.access.iterators] p5.
-However, the rationale in the issue already recognises that the
-difference_type must be signed, so this really looks NAD.
-
    
+The issue was pulled from Ready.  It needs to make clear that only homogenous copying
+is intended to be supported, not coping from a derived to a base.
 
    
 
 
    [
@@ -4124,1059 +3166,990 @@ Batavia (2009-05):
 
 
    
 
    
-We agree with Alisdair's observations.
-
    
-
    
-Move to NAD.
+Howard supplied the following replacement wording
+for paragraph 7 of the proposed resolution:
 
    
+
    
+-7- Postcondition: what() shall return the same NTBS
+  as would be obtained by using static_cast
+  to cast the rhs to the same types as the lhs
+  and then calling what() on that possibly sliced object.
 
    
-
-
-
    Proposed resolution:
    
 
    
-To remove this limitation, I suggest to change the
-operational semantics for this column to:
+Pete asks what "the same NTBS" means.
 
    
-
        { Distance m = n;
-      if (m >= 0)
-        while (m--) --r;
-      else
-        while (m++) ++r;
-      return r; }
-
    
+
    
 
+
    [
+2009-07-30 Niels adds:
+]
    
 
 
+
    
+Further discussion in the thread starting with c++std-lib-24512.
+
    
 
 
 
-
    
-
    459. Requirement for widening in stage 2 is overspecification
    
-
    Section: 22.4.2.1.2 [facet.num.get.virtuals] Status: Open
- Submitter: Martin Sebor Opened: 2004-03-16  Last modified: 2006-12-27
    
-
    View other active issues in [facet.num.get.virtuals].
    
-
    View all other issues in [facet.num.get.virtuals].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    When parsing strings of wide-character digits, the standard
-  requires the library to widen narrow-character "atoms" and compare
-  the widened atoms against the characters that are being parsed.
-  Simply narrowing the wide characters would be far simpler, and
-  probably more efficient.  The two choices are equivalent except in
-  convoluted test cases, and many implementations already ignore the
-  standard and use narrow instead of widen.
    
-
-
    
-First, I disagree that using narrow() instead of widen() would
-necessarily have unfortunate performance implications. A possible
-implementation of narrow() that allows num_get to be implemented
-in a much simpler and arguably comparably efficient way as calling
-widen() allows, i.e. without making a virtual call to do_narrow every
-time, is as follows:
-
    
-
-
      inline char ctype<wchar_t>::narrow (wchar_t wc, char dflt) const
-  {
-      const unsigned wi = unsigned (wc);
-
-      if (wi > UCHAR_MAX)
-          return typeid (*this) == typeid (ctype<wchar_t>) ?
-                 dflt : do_narrow (wc, dflt);
-
-      if (narrow_ [wi] < 0) {
-         const char nc = do_narrow (wc, dflt);
-         if (nc == dflt)
-             return dflt;
-         narrow_ [wi] = nc;
-      }
-
-      return char (narrow_ [wi]);
-  }
-
    
+
    Proposed resolution:
    
 
 
    
-Second, I don't think the change proposed in the issue (i.e., to use
-narrow() instead of widen() during Stage 2) would be at all
-drastic. Existing implementations with the exception of libstdc++
-currently already use narrow() so the impact of the change on programs
-would presumably be isolated to just a single implementation. Further,
-since narrow() is not required to translate alternate wide digit
-representations such as those mentioned in issue 303
-to
-their narrow equivalents (i.e., the portable source characters '0'
-through '9'), the change does not necessarily imply that these
-alternate digits would be treated as ordinary digits and accepted as
-part of numbers during parsing. In fact, the requirement in 22.4.1.1.2
-[locale.ctype.virtuals], p13 forbids narrow() to translate an alternate
-digit character, wc, to an ordinary digit in the basic source
-character set unless the expression
-(ctype<charT>::is(ctype_base::digit, wc) == true) holds. This in
-turn is prohibited by the C standard (7.25.2.1.5, 7.25.2.1.5, and
-5.2.1, respectively) for charT of either char or wchar_t.
+Change 18.8.1 [exception] to:
 
    
 
-
    [Sydney: To a large extent this is a nonproblem. As long as
-you're only trafficking in char and wchar_t we're only dealing with a
-stable character set, so you don't really need either 'widen' or
-'narrow': can just use literals. Finally, it's not even clear whether
-widen-vs-narrow is the right question; arguably we should be using
-codecvt instead.]
    
-
-
-
-
-
    Proposed resolution:
    
-
    Change stage 2 so that implementations are permitted to use either
-technique to perform the comparison:
    
-
      
-  
    1.  call widen on the atoms and compare (either by using
-      operator== or char_traits<charT>::eq) the input with
-      the widened atoms, or
      2. 
-  
    2.  call narrow on the input and compare the narrow input
-      with the atoms
      3. 
-  
    3.  do (1) or (2) only if charT is not char or wchar_t,
-      respectively; i.e., avoid calling widen or narrow
-      if it the source and destination types are the same
      4. 
-
    
+
    
+
    exception(const exception& e) throw();
+exception& operator=(const exception& e) throw();
    
+
    
+
    
+-4- Effects: Copies an exception object.
+
    
+
    
+ -5- Remarks: The effects of calling what() after assignment are implementation-defined.
+
    
+
    
+-5- Throws: Nothing.  This also applies
+to all standard library-defined classes that derive from exception.
+
    
+
    
+-7- Postcondition: strcmp(what(), e.what()) == 0.  This also applies
+to all standard library-defined classes that derive from exception.
+
    
 
+
    
+
    
 
 
 
 
 
    
-
    463. auto_ptr usability issues
    
-
    Section: D.9.1 [auto.ptr] Status: Open
- Submitter: Rani Sharoni Opened: 2003-12-07  Last modified: 2007-11-15
    
-
    View other active issues in [auto.ptr].
    
-
    View all other issues in [auto.ptr].
    
-
    View all issues with Open status.
    
+
    473. underspecified ctype calls
    
+
    Section: 22.4.1.1 [locale.ctype] Status: Review
+ Submitter: Martin Sebor Opened: 2004-07-01  Last modified: 2009-07-17
    
+
    View all issues with Review status.
    
 
    Discussion:
    
-
 
    
-TC1 CWG DR #84 effectively made the template<class Y> operator auto_ptr<Y>()
-member of auto_ptr (20.4.5.3/4) obsolete.
+Most ctype member functions come in two forms: one that operates
+on a single character at a time and another form that operates
+on a range of characters. Both forms are typically described by
+a single Effects and/or Returns clause.
 
    
-
 
    
-The sole purpose of this obsolete conversion member is to enable copy
-initialization base from r-value derived (or any convertible types like
-cv-types) case:
+The Returns clause of each of the single-character non-virtual forms
+suggests that the function calls the corresponding single character
+virtual function, and that the array form calls the corresponding
+virtual array form. Neither of the two forms of each virtual member
+function is required to be implemented in terms of the other.
 
    
-
    #include <memory>
-using std::auto_ptr;
-
-struct B {};
-struct D : B {};
-
-auto_ptr<D> source();
-int sink(auto_ptr<B>);
-int x1 = sink( source() ); // #1 EDG - no suitable copy constructor
-
    
-
 
    
-The excellent analysis of conversion operations that was given in the final
-auto_ptr proposal
-(http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/1997/N1128.pdf)
-explicitly specifies this case analysis (case 4). DR #84 makes the analysis
-wrong and actually comes to forbid the loophole that was exploited by the
-auto_ptr designers.
+There are three problems:
 
    
-
 
    
-I didn't encounter any compliant compiler (e.g. EDG, GCC, BCC and VC) that
-ever allowed this case. This is probably because it requires 3 user defined
-conversions and in fact current compilers conform to DR #84.
+1. One is that while the standard does suggest that each non-virtual
+member function calls the corresponding form of the virtual function,
+it doesn't actually explicitly require it.
 
    
-
-
    
-I was surprised to discover that the obsolete conversion member actually has
-negative impact of the copy initialization base from l-value derived
-case:
    
-
    auto_ptr<D> dp;
-int x2 = sink(dp); // #2 EDG - more than one user-defined conversion applies
-
    
-
 
    
-I'm sure that the original intention was allowing this initialization using
-the template<class Y> auto_ptr(auto_ptr<Y>& a) constructor (20.4.5.1/4) but
-since in this copy initialization it's merely user defined conversion (UDC)
-and the obsolete conversion member is UDC with the same rank (for the early
-overloading stage) there is an ambiguity between them.
+Implementations that cache results from some of the virtual member
+functions for some or all values of their arguments might want to
+call the array form from the non-array form the first time to fill
+the cache and avoid any or most subsequent virtual calls. Programs
+that rely on each form of the virtual function being called from
+the corresponding non-virtual function will see unexpected behavior
+when using such implementations.
 
    
-
 
    
-Removing the obsolete member will have impact on code that explicitly
-invokes it:
+2. The second problem is that either form of each of the virtual
+functions can be overridden by a user-defined function in a derived
+class to return a value that is different from the one produced by
+the virtual function of the alternate form that has not been
+overriden.
 
    
-
    int y = sink(source().operator auto_ptr<B>());
-
    
-
 
    
-IMHO no one ever wrote such awkward code and the reasonable workaround for
-#1 is:
+Thus, it might be possible for, say, ctype::widen(c) to return one
+value, while for ctype::widen(&c, &c + 1, &wc) to set
+wc to another value. This is almost certainly not intended. Both
+forms of every function should be required to return the same result
+for the same character, otherwise the same program using an
+implementation that calls one form of the functions will behave
+differently than when using another implementation that calls the
+other form of the function "under the hood."
 
    
-
    int y = sink( auto_ptr<B>(source()) );
-
    
-
 
    
-I was even more surprised to find out that after removing the obsolete
-conversion member the initialization was still ill-formed:
-int x3 = sink(dp); // #3 EDG - no suitable copy constructor
+3. The last problem is that the standard text fails to specify whether
+one form of any of the virtual functions is permitted to be implemented
+in terms of the other form or not, and if so, whether it is required
+or permitted to call the overridden virtual function or not.
 
    
-
 
    
-This copy initialization semantically requires copy constructor which means
-that both template conversion constructor and the auto_ptr_ref conversion
-member (20.4.5.3/3) are required which is what was explicitly forbidden in
-DR #84. This is a bit amusing case in which removing ambiguity results with
-no candidates.
+Thus, a program that overrides one of the virtual functions so that
+it calls the other form which then calls the base member might end
+up in an infinite loop if the called form of the base implementation
+of the function in turn calls the other form.
 
    
-
 
    
-I also found exception safety issue with auto_ptr related to auto_ptr_ref:
-
    
-
    int f(auto_ptr<B>, std::string);
-auto_ptr<B> source2();
+Lillehammer: Part of this isn't a real problem. We already talk about
+caching. 22.1.1/6 But part is a real problem. ctype virtuals may call
+each other, so users don't know which ones to override to avoid avoid
+infinite loops.
    
 
-// string constructor throws while auto_ptr_ref
-// "holds" the pointer
-int x4 = f(source2(), "xyz"); // #4
-
    
+
    This is a problem for all facet virtuals, not just ctype virtuals,
+so we probably want a blanket statement in clause 22 for all
+facets. The LWG is leaning toward a blanket prohibition, that a
+facet's virtuals may never call each other. We might want to do that
+in clause 27 too, for that matter. A review is necessary.  Bill will
+provide wording.
    
 
-
    
-The theoretic execution sequence that will cause a leak:
-
    
-
      
-
    1. call auto_ptr<B>::operator auto_ptr_ref<B>()
      2. 
-
    2. call string::string(char const*) and throw
      3. 
-
    
+
    [
+2009-07 Frankfurt, Howard provided wording directed by consensus.
+]
    
 
-
    
-According to 20.4.5.3/3 and 20.4.5/2 the auto_ptr_ref conversion member
-returns auto_ptr_ref<Y> that holds *this and this is another defect since
-the type of *this is auto_ptr<X> where X might be different from Y. Several
-library vendors (e.g. SGI) implement auto_ptr_ref<Y> with Y* as member which
-is much more reasonable. Other vendor implemented auto_ptr_ref as
-defectively required and it results with awkward and catastrophic code:
-int oops = sink(auto_ptr<B>(source())); // warning recursive on all control
-paths
-
    
 
-
    
-Dave Abrahams noticed that there is no specification saying that
-auto_ptr_ref copy constructor can't throw.
-
    
 
-
    
-My proposal comes to solve all the above issues and significantly simplify
-auto_ptr implementation. One of the fundamental requirements from auto_ptr
-is that it can be constructed in an intuitive manner (i.e. like ordinary
-pointers) but with strict ownership semantics which yield that source
-auto_ptr in initialization must be non-const. My idea is to add additional
-constructor template with sole propose to generate ill-formed, diagnostic
-required, instance for const auto_ptr arguments during instantiation of
-declaration. This special constructor will not be instantiated for other
-types which is achievable using 14.8.2/2 (SFINAE). Having this constructor
-in hand makes the constructor template<class Y> auto_ptr(auto_ptr<Y> const&)
-legitimate since the actual argument can't be const yet non const r-value
-are acceptable.
-
    
 
+
    Proposed resolution:
    
 
    
-This implementation technique makes the "private auxiliary class"
-auto_ptr_ref obsolete and I found out that modern C++ compilers (e.g. EDG,
-GCC and VC) consume the new implementation as expected and allow all
-intuitive initialization and assignment cases while rejecting illegal cases
-that involve const auto_ptr arguments.
+Add paragraph 3 to 22.4 [locale.categories]:
 
    
 
-
    The proposed auto_ptr interface:
    
+
    
+-3- Within this clause it is unspecified if one virtual function calls another
+virtual function.
+
    
 
-
    namespace std {
-    template<class X> class auto_ptr {
-    public:
-        typedef X element_type;
 
-        // 20.4.5.1 construct/copy/destroy:
-        explicit auto_ptr(X* p=0) throw();
-        auto_ptr(auto_ptr&) throw();
-        template<class Y> auto_ptr(auto_ptr<Y> const&) throw();
-        auto_ptr& operator=(auto_ptr&) throw();
-        template<class Y> auto_ptr& operator=(auto_ptr<Y>) throw();
-        ~auto_ptr() throw();
 
-        // 20.4.5.2 members:
-        X& operator*() const throw();
-        X* operator->() const throw();
-        X* get() const throw();
-        X* release() throw();
-        void reset(X* p=0) throw();
 
-    private:
-        template<class U>
-        auto_ptr(U& rhs, typename
-unspecified_error_on_const_auto_ptr<U>::type = 0);
-    };
-}
-
    
+
+
    
+
    484. Convertible to T
    
+
    Section: 24.2.2 [input.iterators] Status: Open
+ Submitter: Chris Jefferson Opened: 2004-09-16  Last modified: 2009-07-28
    
+
    View all other issues in [input.iterators].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
+
    From comp.std.c++:
    
 
 
    
-One compliant technique to implement the unspecified_error_on_const_auto_ptr
-helper class is using additional private auto_ptr member class template like
-the following:
+I note that given an input iterator a for type T, 
+then *a only has to be "convertable to T", not actually of type T.
 
    
-
    template<typename T> struct unspecified_error_on_const_auto_ptr;
 
-template<typename T>
-struct unspecified_error_on_const_auto_ptr<auto_ptr<T> const>
-{ typedef typename auto_ptr<T>::const_auto_ptr_is_not_allowed type; };
-
    
+
    Firstly, I can't seem to find an exact definition of "convertable to T". 
+While I assume it is the obvious definition (an implicit conversion), I 
+can't find an exact definition. Is there one?
    
 
-
    
-There are other techniques to implement this helper class that might work
-better for different compliers (i.e. better diagnostics) and therefore I
-suggest defining its semantic behavior without mandating any specific
-implementation. IMO, and I didn't found any compiler that thinks otherwise,
-14.7.1/5 doesn't theoretically defeat the suggested technique but I suggest
-verifying this with core language experts.
-
    
+
    Slightly more worryingly, there doesn't seem to be any restriction on 
+the this type, other than it is "convertable to T". Consider two input 
+iterators a and b. I would personally assume that most people would 
+expect *a==*b would perform T(*a)==T(*b), however it doesn't seem that 
+the standard requires that, and that whatever type *a is (call it U) 
+could have == defined on it with totally different symantics and still 
+be a valid inputer iterator.
    
 
-
    Further changes in standard text:
    
-
    Remove section 20.4.5.3
    
+
    Is this a correct reading? When using input iterators should I write 
+T(*a) all over the place to be sure that the object i'm using is the 
+class I expect?
    
 
-
    Change 20.4.5/2 to read something like:
-Initializing auto_ptr<X> from const auto_ptr<Y> will result with unspecified
-ill-formed declaration that will require unspecified diagnostic.
    
+
    This is especially a nuisance for operations that are defined to be
+  "convertible to bool".  (This is probably allowed so that
+  implementations could return say an int and avoid an unnessary
+  conversion. However all implementations I have seen simply return a
+  bool anyway.  Typical implemtations of STL algorithms just write
+  things like while(a!=b && *a!=0).  But strictly
+  speaking, there are lots of types that are convertible to T but
+  that also overload the appropriate operators so this doesn't behave
+  as expected.
    
 
-
    Change 20.4.5.1/4,5,6 to read:
    
+
    If we want to make code like this legal (which most people seem to
+  expect), then we'll need to tighten up what we mean by "convertible
+  to T".
    
 
-
    template<class Y> auto_ptr(auto_ptr<Y> const& a) throw();
    
-
     4 Requires: Y* can be implicitly converted to X*.
    
-
     5 Effects: Calls const_cast<auto_ptr<Y>&>(a).release().
    
-
     6 Postconditions: *this holds the pointer returned from a.release().
    
+
    [Lillehammer: The first part is NAD, since "convertible" is
+ well-defined in core. The second part is basically about pathological
+ overloads. It's a minor problem but a real one. So leave open for
+ now, hope we solve it as part of iterator redesign.]
    
 
-
    Change 20.4.5.1/10
    
-
    template<class Y> auto_ptr& operator=(auto_ptr<Y> a) throw();
-
    
-
    
-10 Requires: Y* can be implicitly converted to X*. The expression delete
-get() is well formed.
-
    
 
-
    LWG TC DR #127 is obsolete.
    
+
    [
+2009-07-28 Reopened by Alisdair.  No longer solved by concepts.
+]
    
 
-
    
-Notice that the copy constructor and copy assignment operator should remain
-as before and accept non-const auto_ptr& since they have effect on the form
-of the implicitly declared copy constructor and copy assignment operator of
-class that contains auto_ptr as member per 12.8/5,10:
-
    
-
    struct X {
-    // implicit X(X&)
-    // implicit X& operator=(X&)
-    auto_ptr<D> aptr_;
-};
-
    
 
-
    
-In most cases this indicates about sloppy programming but preserves the
-current auto_ptr behavior.
-
    
-
-
    
-Dave Abrahams encouraged me to suggest fallback implementation in case that
-my suggestion that involves removing of auto_ptr_ref will not be accepted.
-In this case removing the obsolete conversion member to auto_ptr<Y> and
-20.4.5.3/4,5 is still required in order to eliminate ambiguity in legal
-cases. The two constructors that I suggested will co exist with the current
-members but will make auto_ptr_ref obsolete in initialization contexts.
-auto_ptr_ref will be effective in assignment contexts as suggested in DR
-#127 and I can't see any serious exception safety issues in those cases
-(although it's possible to synthesize such). auto_ptr_ref<X> semantics will
-have to be revised to say that it strictly holds pointer of type X and not
-reference to an auto_ptr for the favor of cases in which auto_ptr_ref<Y> is
-constructed from auto_ptr<X> in which X is different from Y (i.e. assignment
-from r-value derived to base).
-
    
-
-
    [Redmond: punt for the moment. We haven't decided yet whether we
-  want to fix auto_ptr for C++-0x, or remove it and replace it with
-  move_ptr and unique_ptr.]
    
 
 
-
    [
-Oxford 2007: Recommend NAD.  We're just going to deprecate it.  It still works for simple use cases
-and people know how to deal with it.  Going forward unique_ptr is the recommended
-tool.
-]
    
+
    Proposed resolution:
    
 
 
+
    Rationale:
    
 
    [
-2007-11-09: Reopened at the request of David Abrahams, Alisdair Meredith and Gabriel Dos Reis.
+San Francisco:
 ]
    
 
 
+
    
+Solved by
+N2758.
+
    
 
 
-
    Proposed resolution:
    
-
    
-Change the synopsis in D.9.1 [auto.ptr]:
-
    
-
-
    namespace std { 
-  template <class Y> struct auto_ptr_ref {};
-
-  // exposition only
-  template <class T> struct constant_object;
-
-  // exposition only
-  template <class T>
-  struct cannot_transfer_ownership_from
-    : constant_object<T> {};
 
-  template <class X> class auto_ptr { 
-  public: 
-    typedef X element_type; 
 
-    // D.9.1.1 construct/copy/destroy: 
-    explicit auto_ptr(X* p =0) throw(); 
-    auto_ptr(auto_ptr&) throw(); 
-    template<class Y> auto_ptr(auto_ptr<Y> const&) throw(); 
-    auto_ptr& operator=(auto_ptr&) throw(); 
-    template<class Y> auto_ptr& operator=(auto_ptr<Y>&) throw();
-    auto_ptr& operator=(auto_ptr_ref<X> r) throw();
-    ~auto_ptr() throw(); 
 
-    // D.9.1.2 members: 
-    X& operator*() const throw();
-    X* operator->() const throw();
-    X* get() const throw();
-    X* release() throw();
-    void reset(X* p =0) throw();
 
-    // D.9.1.3 conversions:
-    auto_ptr(auto_ptr_ref<X>) throw();
-    template<class Y> operator auto_ptr_ref<Y>() throw();
-    template<class Y> operator auto_ptr<Y>() throw();
 
-    // exposition only
-    template<class U>
-    auto_ptr(U& rhs, typename cannot_transfer_ownership_from<U>::error = 0);
-  }; 
+
    
+
    485. output iterator insufficiently constrained
    
+
    Section: 24.2.3 [output.iterators] Status: Open
+ Submitter: Chris Jefferson Opened: 2004-10-13  Last modified: 2009-07-21
    
+
    View all other issues in [output.iterators].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
+
    
+The note on 24.1.2 Output iterators insufficiently limits what can be
+performed on output iterators. While it requires that each iterator is
+progressed through only once and that each iterator is written to only
+once, it does not require the following things:
    
 
-  template <> class auto_ptr<void> 
-  { 
-  public: 
-    typedef void element_type; 
-  }; 
+
    Note: Here it is assumed that x is an output iterator of type X which
+has not yet been assigned to.
    
 
-}
-
    
+
    a) That each value of the output iterator is written to:
+The standard allows:
+++x; ++x; ++x;
+
    
 
 
    
-Remove D.9.1.3 [auto.ptr.conv].
+b) That assignments to the output iterator are made in order
+X a(x); ++a; *a=1; *x=2; is allowed
 
    
 
 
    
-Change D.9.1 [auto.ptr], p3:
+c) Chains of output iterators cannot be constructed:
+X a(x); ++a; X b(a); ++b; X c(b); ++c; is allowed, and under the current
+wording (I believe) x,a,b,c could be written to in any order.
 
    
 
-
    
-The auto_ptr provides a semantics of strict ownership. An
-auto_ptr owns the object it holds a pointer to. Copying an
-auto_ptr copies the pointer and transfers ownership to the
-destination. If more than one auto_ptr owns the same object at
-the same time the behavior of the program is undefined. Templates
-constant_object and cannot_transfer_ownership_from,
-and the final constructor of auto_ptr are for exposition only.
-For any types X and Y, initializing
-auto_ptr<X> from const auto_ptr<Y> is
-ill-formed, diagnostic required. [Note: The uses of
-auto_ptr include providing temporary exception-safety for
-dynamically allocated memory, passing ownership of dynamically allocated
-memory to a function, and returning dynamically allocated memory from a
-function. auto_ptr does not meet the CopyConstructible
-and Assignable requirements for Standard Library container
-elements and thus instantiating a Standard Library container with an
-auto_ptr results in undefined behavior. -- end note]
-
    
+
    I do not believe this was the intension of the standard?
    
+
    [Lillehammer: Real issue.  There are lots of constraints we
+  intended but didn't specify.  Should be solved as part of iterator
+  redesign.]
    
 
-
    
-Change D.9.1.1 [auto.ptr.cons], p5:
-
    
 
-
    
-
    template<class Y> auto_ptr(auto_ptr<Y> const& a) throw();
-
    
-
    
-
    
-Requires: Y* can be implicitly converted to X*.
-
    
-
    
-Effects: Calls const_cast<auto_ptr<Y>&>(a).release().
-
    
-
    
-Postconditions: *this holds the pointer returned from a.release().
-
    
-
    
-
    
+
    [
+2009-07 Frankfurt
+]
    
 
-
    
-Change D.9.1.1 [auto.ptr.cons], p10:
-
    
 
 
    
-
    template<class Y> auto_ptr& operator=(auto_ptr<Y>& a) throw();
-
    
-
    
-
    
-Requires: Y* can be implicitly converted to X*.
-The expression delete get() is well formed.
-
    
-
    
-Effects: Calls reset(a.release()).
-
    
-
    
-Returns: *this.
-
    
-
    
+Bill provided wording according to consensus.
 
    
 
+
    [
+2009-07-21 Alsidair requests change from Review to Open.  See thread starting
+with c++std-lib-24459 for discussion.
+]
    
 
 
 
 
-
-
    
-
    466. basic_string ctor should prevent null pointer error
    
-
    Section: 21.4.1 [string.require] Status: Open
- Submitter: Daniel Frey Opened: 2004-06-10  Last modified: 2009-05-23
    
-
    View other active issues in [string.require].
    
-
    View all other issues in [string.require].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
+
    Proposed resolution:
    
 
    
-Today, my colleagues and me wasted a lot of time. After some time, I
-found the problem. It could be reduced to the following short example:
+Change Table 101 — Output iterator requirements in 24.2.3 [output.iterators]:
 
    
+
    
+
+
+
+
+
+
+
+
 
-
      #include <string>
-  int main() { std::string( 0 ); }
-
    
-
-
    The problem is that the tested compilers (GCC 2.95.2, GCC 3.3.1 and
-Comeau online) compile the above without errors or warnings! The
-programs (at least for the GCC) resulted in a SEGV.
    
-
-
    I know that the standard explicitly states that the ctor of string
-requires a char* which is not zero. STLs could easily detect the above
-case with a private ctor for basic_string which takes a single 'int'
-argument. This would catch the above code at compile time and would not
-ambiguate any other legal ctors.
    
+
+
+
+
+
+
 
-
    [Redmond: No great enthusiasm for doing this.  If we do,
-  however, we want to do it for all places that take charT*
-  pointers, not just the single-argument constructor.  The other
-  question is whether we want to catch this at compile time (in which
-  case we catch the error of a literal 0, but not an expression whose
-  value is a null pointer), at run time, or both.
-  Recommend NAD.  Relegate this functionality to debugging implementations.]
    
+
+
+
+
+
+
 
+
+
+
+
+
+
 
-
    [
-Post Summit: Alisdair requests this be re-opened as several new language facilities are
-designed to solve exactly this kind of problem.
-]
    
+
+
+
+
+
+
 
+
+
+
+
+
+
 
-
    [
-Batavia (2009-05):
-]
    
+
+
+
+
+
+
 
-
    
-We are unable to achieve consensus on an approach to a resolution.
-There is some sentiment for treating this as a QOI matter.
-It is also possible
-that when string is brought into the concepts world,
-this issue might be addressed in that context.
+
    Table 101 — Output iterator requirements
    ExpressionReturn typeOperational semanticsAssertion/note pre-/post-condition
    
+X(a)
+
+ 
+
+ 
+
+a = t is equivalent to X(a) = t. note: a destructor is assumed.
+
    
+X u(a);
    
+X u = a;
+    		
+ 
+
+ 
+
+ 
+
    
+*r = o
+
+result is not used
+
+ 
+
+ 
+
    
+++r
+
+X&
+
+ 
+
+&r == &++r
+
    
+r++
+
+convertible to const X&
+
+{X tmp = r;
    ++r;
    return tmp;}    
+    		
+ 
+
    
+*r++ = o
    *r = o, ++r
    *r = o, r++    
+    		
+result is not used usable
+
+ 
+
+Note: only these forms permitted
+
    
 
    
 
 
-
    Proposed resolution:
    
-
    
-Add to the synopsis in 21.4 [basic.string]
-
    
-
-
    basic_string( nullptr_t ) = delete;
-
    
-
-
 
 
 
 
    
-
    471. result of what() implementation-defined
    
-
    Section: 18.7.1 [type.info] Status: Open
- Submitter: Martin Sebor Opened: 2004-06-28  Last modified: 2009-05-23
    
-
    View all other issues in [type.info].
    
-
    View all issues with Open status.
    
+
    498. Requirements for partition() and stable_partition() too strong
    
+
    Section: 25.4.13 [alg.partitions] Status: Ready
+ Submitter: Sean Parent, Joe Gottman Opened: 2005-05-04  Last modified: 2009-07-15
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
+
    
+Problem:
+The iterator requirements for partition() and stable_partition() [25.2.12]
+are listed as BidirectionalIterator, however, there are efficient algorithms
+for these functions that only require ForwardIterator that have been known
+since before the standard existed. The SGI implementation includes these (see
+http://www.sgi.com/tech/stl/partition.html
+and
+http://www.sgi.com/tech/stl/stable_partition.html).
+
    
 
-
    [lib.exception] specifies the following:
    
-
        exception (const exception&) throw();
-    exception& operator= (const exception&) throw();
+
    [
+2009-04-30 Alisdair adds:
+]
    
 
-    -4- Effects: Copies an exception object.
-    -5- Notes: The effects of calling what() after assignment
-        are implementation-defined.
-
    
 
+
    
 
    
-First, does the Note only apply to the assignment operator? If so,
-what are the effects of calling what() on a copy of an object? Is
-the returned pointer supposed to point to an identical copy of
-the NTBS returned by what() called on the original object or not?
+Now we have concepts this is easier to express!
 
    
-
 
    
-Second, is this Note intended to extend to all the derived classes
-in section 19? I.e., does the standard provide any guarantee for
-the effects of what() called on a copy of any of the derived class
-described in section 19?
+Proposed resolution:
 
    
-
 
    
-Finally, if the answer to the first question is no, I believe it
-constitutes a defect since throwing an exception object typically
-implies invoking the copy ctor on the object. If the answer is yes,
-then I believe the standard ought to be clarified to spell out
-exactly what the effects are on the copy (i.e., after the copy
-ctor was called).
+Add the following signature to:
+
    
+
    
+Header <algorithm> synopsis 25.2 [algorithms.syn]
    
+p3 Partitions 25.4.13 [alg.partitions]
 
    
+
     template<ForwardIterator Iter, Predicate<auto, Iter::value_type> Pred>
+   requires ShuffleIterator<Iter>
+         && CopyConstructible<Pred>
+   Iter partition(Iter first, Iter last, Pred pred);
+
    
 
-
    [Redmond: Yes, this is fuzzy.  The issue of derived classes is
-  fuzzy too.]
    
+
    
+Update p3 Partitions 25.4.13 [alg.partitions]:
+
    
 
+
    
+
    
+Complexity: At most (last - first)/2 swaps. Exactly last - first
+applications of the predicate
+are done.
+
+If Iter satisfies BidirectionalIterator, at most (last -
+first)/2 swaps. Exactly last - first applications of the predicate
+are done.
+
+
    
+
    
+If Iter merely satisfied ForwardIterator at most (last - first) swaps
+are done. Exactly (last - first) applications of the predicate are done.
+
    
+
    
 
-
    [
-Batavia: Howard provided wording.
-]
    
+
    
+[Editorial note: I looked for existing precedent in how we might call out
+distinct overloads overloads from a set of constrained templates, but there
+is not much existing practice to lean on.   advance/distance were the only
+algorithms I could find, and that wording is no clearer.]
+
    
 
+
    
 
 
    [
-Bellevue:
+2009-07 Frankfurt
 ]
    
 
 
 
    
 
    
-Eric concerned this is unimplementable, due to nothrow guarantees.
-Suggested implementation would involve reference counting.
+Hinnant: if you want to partition your std::forward_list, you'll need
+partition() to accept ForwardIterators.
 
    
 
    
-Is the implied reference counting subtle enough to call out a note on
-implementation? Probably not.
+No objection to Ready.
 
    
 
    
-If reference counting required, could we tighten specification further
-to require same pointer value? Probably an overspecification, especially
-if exception classes defer evalutation of final string to calls to
-what().
+Move to Ready.
 
    
+
    
+
+
+
+
    Proposed resolution:
    
 
    
-Remember issue moved open and not resolved at Batavia, but cannot
-remember who objected to canvas a disenting opinion - please speak up if
-you disagree while reading these minutes!
+Change 25.2.12 from 
    
+
    template<class BidirectionalIterator, class Predicate> 
+BidirectionalIterator partition(BidirectionalIterato r first, 
+                                BidirectionalIterator last, 
+                                Predicate pred); 
+
    
+
    to 
    
+
    template<class ForwardIterator, class Predicate> 
+ForwardIterator partition(ForwardIterator first, 
+                          ForwardIterator last, 
+                          Predicate pred); 
+
    
+
    Change the complexity from 
    
+
+
    
+At most (last - first)/2 swaps are done. Exactly (last - first) 
+applications of the predicate are done. 
+
    
+
+
    to 
    
+
+
    
+If ForwardIterator is a bidirectional_iterator, at most (last - first)/2 
+swaps are done; otherwise at most (last - first) swaps are done. Exactly 
+(last - first) applications of the predicate are done. 
+
    
+
+
+
+
    Rationale:
    
+
    
+Partition is a "foundation" algorithm useful in many contexts (like sorting
+as just one example) - my motivation for extending it to include forward
+iterators is foward_list - without this extension you can't partition an foward_list
+(without writing your own partition). Holes like this in the standard
+library weaken the argument for generic programming (ideally I'd be able
+to provide a library that would refine std::partition() to other concepts
+without fear of conflicting with other libraries doing the same - but
+that is a digression). I consider the fact that partition isn't defined
+to work for ForwardIterator a minor embarrassment.
 
    
+
+
    [Mont Tremblant: Moved to Open, request motivation and use cases
+by next meeting. Sean provided further rationale by post-meeting
+mailing.]
    
+
+
+
+
+
+
+
+
    
+
    532. Tuple comparison
    
+
    Section: 20.5.2.5 [tuple.rel], TR1 6.1.3.5 [tr.tuple.rel] Status: Open
+ Submitter: David Abrahams Opened: 2005-11-29  Last modified: 2009-07-28
    
+
    View all other issues in [tuple.rel].
    
+
    View all issues with Open status.
    
+
    Duplicate of: 348
    
+
    Discussion:
    
 
    
-Move to Ready as we are accepting words unmodified.
+Where possible, tuple comparison operators <,<=,=>, and > ought to be
+defined in terms of std::less rather than operator<, in order to
+support comparison of tuples of pointers.  
 
    
-
    
 
 
    [
-Sophia Antipolis:
+2009-07-28 Reopened by Alisdair.  No longer solved by concepts.
 ]
    
 
 
-
    
-The issue was pulled from Ready.  It needs to make clear that only homogenous copying
-is intended to be supported, not coping from a derived to a base.
-
    
 
-
    [
-Batavia (2009-05):
-]
    
 
-
    
-
    
-Howard supplied the following replacement wording
-for paragraph 7 of the proposed resolution:
-
    
-
    
--7- Postcondition: what() shall return the same NTBS
-  as would be obtained by using static_cast
-  to cast the rhs to the same types as the lhs
-  and then calling what() on that possibly sliced object.
-
    
+
    Proposed resolution:
    
 
    
-Pete asks what "the same NTBS" means.
+change 6.1.3.5/5 from:
 
    
-
    
 
-
-
    Proposed resolution:
    
+
    
+  Returns: The result of a lexicographical comparison between t and
+  u. The result is defined as: (bool)(get<0>(t) < get<0>(u)) ||
+  (!(bool)(get<0>(u) < get<0>(t)) && ttail < utail), where rtail for
+  some tuple r is a tuple containing all but the first element of
+  r. For any two zero-length tuples e and f, e < f returns false.
+
    
 
 
    
-Change 18.8.1 [exception] to:
+to:
 
    
 
 
    
-
    exception(const exception& e) throw();
-exception& operator=(const exception& e) throw();
    
-
    
 
    
--4- Effects: Copies an exception object.
+  Returns: The result of a lexicographical comparison between t and
+  u. For any two zero-length tuples e and f, e < f returns false.
+  Otherwise, the result is defined as: cmp( get<0>(t), get<0>(u)) ||
+  (!cmp(get<0>(u), get<0>(t)) && ttail < utail), where rtail for some
+  tuple r is a tuple containing all but the first element of r, and
+  cmp(x,y) is an unspecified function template defined as follows.
 
    
 
    
- -5- Remarks: The effects of calling what() after assignment are implementation-defined.
+  Where T is the type of x and U is the type of y:
 
    
+
 
    
--5- Throws: Nothing.  This also applies
-to all standard library-defined classes that derive from exception.
+     if T and U are pointer types and T is convertible to U, returns
+     less<U>()(x,y)
 
    
+
 
    
--7- Postcondition: strcmp(what(), e.what()) == 0.  This also applies
-to all standard library-defined classes that derive from exception.
+     otherwise, if T and U are pointer types, returns less<T>()(x,y)
 
    
 
+
    
+     otherwise, returns (bool)(x < y)
+
    
 
    
+
+
    [
+Berlin: This issue is much bigger than just tuple (pair, containers,
+algorithms). Dietmar will survey and work up proposed wording.
+]
    
+
+
+
+
+
    Rationale:
    
+
    
+Recommend NAD.  This will be fixed with the next revision of concepts.
+
    
+
+
    [
+San Francisco:
+]
    
+
+
+
    
+Solved by
+N2770.
 
    
 
 
 
 
+
 
    
-
    473. underspecified ctype calls
    
-
    Section: 22.4.1.1 [locale.ctype] Status: Open
- Submitter: Martin Sebor Opened: 2004-07-01  Last modified: 2006-12-27
    
+
    539. partial_sum and adjacent_difference should mention requirements
    
+
    Section: 26.7.3 [partial.sum] Status: Open
+ Submitter: Marc Schoolderman Opened: 2006-02-06  Last modified: 2009-07-30
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-Most ctype member functions come in two forms: one that operates
-on a single character at a time and another form that operates
-on a range of characters. Both forms are typically described by
-a single Effects and/or Returns clause.
+There are some problems in the definition of partial_sum and
+adjacent_difference in 26.4 [lib.numeric.ops]
 
    
+
 
    
-The Returns clause of each of the single-character non-virtual forms
-suggests that the function calls the corresponding single character
-virtual function, and that the array form calls the corresponding
-virtual array form. Neither of the two forms of each virtual member
-function is required to be implemented in terms of the other.
+Unlike accumulate and inner_product, these functions are not
+parametrized on a "type T", instead, 26.4.3 [lib.partial.sum] simply
+specifies the effects clause as;
+
    
+
+
    
+Assigns to every element referred to by iterator i in the range
+[result,result + (last - first)) a value correspondingly equal to
 
    
+
    ((...(* first + *( first + 1)) + ...) + *( first + ( i - result )))
+
    
+
    
+
 
    
-There are three problems:
+And similarly for BinaryOperation. Using just this definition, it seems
+logical to expect that:
 
    
+
+
+
    char i_array[4] = { 100, 100, 100, 100 };
+int  o_array[4];
+
+std::partial_sum(i_array, i_array+4, o_array);
+
    
+
 
    
-1. One is that while the standard does suggest that each non-virtual
-member function calls the corresponding form of the virtual function,
-it doesn't actually explicitly require it.
+Is equivalent to
 
    
+
+
    int o_array[4] = { 100, 100+100, 100+100+100, 100+100+100+100 };
+
    
+
 
    
-Implementations that cache results from some of the virtual member
-functions for some or all values of their arguments might want to
-call the array form from the non-array form the first time to fill
-the cache and avoid any or most subsequent virtual calls. Programs
-that rely on each form of the virtual function being called from
-the corresponding non-virtual function will see unexpected behavior
-when using such implementations.
+i.e. 100, 200, 300, 400, with addition happening in the result type,
+int.
 
    
+
 
    
-2. The second problem is that either form of each of the virtual
-functions can be overridden by a user-defined function in a derived
-class to return a value that is different from the one produced by
-the virtual function of the alternate form that has not been
-overriden.
+Yet all implementations I have tested produce 100, -56, 44, -112,
+because they are using an accumulator of the InputIterator's
+value_type, which in this case is char, not int.
 
    
+
 
    
-Thus, it might be possible for, say, ctype::widen(c) to return one
-value, while for ctype::widen(&c, &c + 1, &wc) to set
-wc to another value. This is almost certainly not intended. Both
-forms of every function should be required to return the same result
-for the same character, otherwise the same program using an
-implementation that calls one form of the functions will behave
-differently than when using another implementation that calls the
-other form of the function "under the hood."
+The issue becomes more noticeable when the result of the expression *i +
+*(i+1) or binary_op(*i, *i-1) can't be converted to the
+value_type. In a contrived example:
 
    
+
+
    enum not_int { x = 1, y = 2 };
+...
+not_int e_array[4] = { x, x, y, y };
+std::partial_sum(e_array, e_array+4, o_array);
+
    
+
 
    
-3. The last problem is that the standard text fails to specify whether
-one form of any of the virtual functions is permitted to be implemented
-in terms of the other form or not, and if so, whether it is required
-or permitted to call the overridden virtual function or not.
+Is it the intent that the operations happen in the input type, or in
+the result type?
 
    
+
 
    
-Thus, a program that overrides one of the virtual functions so that
-it calls the other form which then calls the base member might end
-up in an infinite loop if the called form of the base implementation
-of the function in turn calls the other form.
+If the intent is that operations happen in the result type, something
+like this should be added to the "Requires" clause of 26.4.3/4
+[lib.partial.sum]:
 
    
-
    
-Lillehammer: Part of this isn't a real problem. We already talk about
-caching. 22.1.1/6 But part is a real problem. ctype virtuals may call
-each other, so users don't know which ones to override to avoid avoid
-infinite loops.
    
-
-
    This is a problem for all facet virtuals, not just ctype virtuals,
-so we probably want a blanket statement in clause 22 for all
-facets. The LWG is leaning toward a blanket prohibition, that a
-facet's virtuals may never call each other. We might want to do that
-in clause 27 too, for that matter. A review is necessary.  Bill will
-provide wording.
    
 
+
    
+The type of *i + *(i+1) or binary_op(*i, *(i+1)) shall meet the
+requirements of CopyConstructible (20.1.3) and Assignable
+(23.1) types.
+
    
 
-
    Proposed resolution:
    
+
    
+(As also required for T in 26.4.1 [lib.accumulate] and 26.4.2
+[lib.inner.product].)
+
    
 
+
    
+The "auto initializer" feature proposed in
+N1894
+is not required to
+implement partial_sum this way. The 'narrowing' behaviour can still be
+obtained by using the std::plus<> function object.
+
    
 
+
    
+If the intent is that operations happen in the input type, then
+something like this should be added instead;
+
    
 
+
    
+The type of *first shall meet the requirements of
+CopyConstructible (20.1.3) and Assignable (23.1) types.
+The result of *i + *(i+1) or binary_op(*i, *(i+1)) shall be
+convertible to this type.
+
    
 
-
    
-
    485. output iterator insufficently constrained
    
-
    Section: 24.2.3 [output.iterators] Status: Open
- Submitter: Chris Jefferson Opened: 2004-10-13  Last modified: 2006-12-27
    
-
    View all other issues in [output.iterators].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
 
    
-The note on 24.1.2 Output iterators insufficently limits what can be
-performed on output iterators. While it requires that each iterator is
-progressed through only once and that each iterator is written to only
-once, it does not require the following things:
    
-
-
    Note: Here it is assumed that x is an output iterator of type X which
-has not yet been assigned to.
    
+The 'widening' behaviour can then be obtained by writing a custom proxy
+iterator, which is somewhat involved.
+
    
 
-
    a) That each value of the output iterator is written to:
-The standard allows:
-++x; ++x; ++x;
+
    
+In both cases, the semantics should probably be clarified.
 
    
 
 
    
-b) That assignments to the output iterator are made in order
-X a(x); ++a; *a=1; *x=2; is allowed
+26.4.4 [lib.adjacent.difference] is similarly underspecified, although
+all implementations seem to perform operations in the 'result' type:
 
    
 
+
    unsigned char i_array[4] = { 4, 3, 2, 1 };
+int o_array[4];
+
+std::adjacent_difference(i_array, i_array+4, o_array);
+
    
+
 
    
-c) Chains of output iterators cannot be constructed:
-X a(x); ++a; X b(a); ++b; X c(b); ++c; is allowed, and under the current
-wording (I believe) x,a,b,c could be written to in any order.
+o_array is 4, -1, -1, -1 as expected, not 4, 255, 255, 255.
 
    
 
-
    I do not believe this was the intension of the standard?
    
-
    [Lillehammer: Real issue.  There are lots of constraints we
-  intended but didn't specify.  Should be solved as part of iterator
-  redesign.]
    
+
    
+In any case, adjacent_difference doesn't mention the requirements on the
+value_type; it can be brought in line with the rest of 26.4
+[lib.numeric.ops] by adding the following to 26.4.4/2
+[lib.adjacent.difference]:
+
    
 
+
    
+The type of *first shall meet the requirements of
+CopyConstructible (20.1.3) and Assignable (23.1) types."
+
    
+
    [
+Berlin: Giving output iterator's value_types very controversial. Suggestion of
+adding signatures to allow user to specify "accumulator".
+]
    
 
 
-
    Proposed resolution:
    
+
    [
+Bellevue:
+]
    
 
 
+
    
+The intent of the algorithms is to perform their calculations using the type of the input iterator.
+Proposed wording provided.
+
    
 
+
    [
+Sophia Antipolis:
+]
    
 
 
-
    
-
    492. Invalid iterator arithmetic expressions
    
-
    Section: 17.5.1.4 [structure.specifications] Status: Open
- Submitter: Thomas Mang Opened: 2004-12-12  Last modified: 2009-05-10
    
-
    View other active issues in [structure.specifications].
    
-
    View all other issues in [structure.specifications].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    Various clauses other than clause 25 make use of iterator arithmetic not
-supported by the iterator category in question.
-Algorithms in clause 25 are exceptional because of 25 [lib.algorithms],
-paragraph 9, but this paragraph does not provide semantics to the
-expression "iterator - n", where n denotes a value of a distance type
-between iterators.
    
+
    
+We did not agree that the proposed resolution was correct. For example,
+when the arguments are types (float*, float*, double*), the
+highest-quality solution would use double as the type of the
+accumulator. If the intent of the wording is to require that the type of
+the accumulator must be the input_iterator's value_type, the wording
+should specify it.
+
    
 
-
    1) Examples of current wording:
    
+
    [
+2009-05-09 Alisdair adds:
+]
    
 
-
    Current wording outside clause 25:
    
 
+
    
 
    
-23.2.2.4 [lib.list.ops], paragraphs 19-21: "first + 1", "(i - 1)",
-"(last - first)"
-23.3.1.1 [lib.map.cons], paragraph 4: "last - first"
-23.3.2.1 [lib.multimap.cons], paragraph 4: "last - first"
-23.3.3.1 [lib.set.cons], paragraph 4: "last - first"
-23.3.4.1 [lib.multiset.cons], paragraph 4: "last - first"
-24.4.1 [lib.reverse.iterators], paragraph 1: "(i - 1)"
+Now that we have the facility, the 'best' accumulator type could probably be
+deduced as:
+
    
+
    std::common_type<InIter::value_type, OutIter::reference>::type
+
    
+
    
+This type would then have additional requirements of constructability and
+incrementability/assignability.
+
    
+
    
+If this extracting an accumulator type from a pair/set of iterators (with
+additional requirements on that type) is a problem for multiple functions,
+it might be worth extracting into a SharedAccumulator concept or similar.
 
    
-
 
    
-[Important note: The list is not complete, just an illustration. The
-same issue might well apply to other paragraphs not listed here.]
    
+I'll go no further in writing up wording now, until the group gives a
+clearer indication of preferred direction.
+
    
+
    
 
-
    None of these expressions is valid for the corresponding iterator
-category.
    
+
    [
+2009-07 Frankfurt
+]
    
 
-
    Current wording in clause 25:
    
 
-
    
-25.1.1 [lib.alg.foreach], paragraph 1: "last - 1"
-25.1.3 [lib.alg.find.end], paragraph 2: "[first1, last1 -
-(last2-first2))"
-25.2.8 [lib.alg.unique], paragraph 1: "(i - 1)"
-25.2.8 [lib.alg.unique], paragraph 5: "(i - 1)"
-
    
+
    
+The proposed resolution isn't quite right. For example, "the type of
+*first" should be changed to "iterator::value_type" or similar. Daniel
+volunteered to correct the wording.
+
    
 
-
    
-However, current wording of 25 [lib.algorithms], paragraph 9 covers
-neither of these four cases:
    
+
    [
+2009-07-29 Daniel corrected wording.
+]
    
 
-
    Current wording of 25 [lib.algorithms], paragraph 9:
    
 
-
    
-"In the description of the algorithms operator + and - are used for some
-of the iterator categories for which they do not have to be defined. In
-these cases the semantics of a+n is the same as that of
    
-
    {X tmp = a;
-advance(tmp, n);
-return tmp;
-}
-
    
-
    and that of b-a is the same as of return distance(a, b)"
    
 
-
    
-This paragrpah does not take the expression "iterator - n" into account,
-where n denotes a value of a distance type between two iterators [Note:
-According to current wording, the expression "iterator - n" would be
-resolved as equivalent to "return distance(n, iterator)"]. Even if the
-expression "iterator - n" were to be reinterpreted as equivalent to
-"iterator + -n" [Note: This would imply that "a" and "b" were
-interpreted implicitly as values of iterator types, and "n" as value of
-a distance type], then 24.3.4/2 interfers because it says: "Requires: n
-may be negative only for random access and bidirectional iterators.",
-and none of the paragraphs quoted above requires the iterators on which
-the algorithms operate to be of random access or bidirectional category.
-
    
+
    Proposed resolution:
    
 
-
    2) Description of intended behavior:
    
 
+
+
      
+
    1. 
 
      
-For the rest of this Defect Report, it is assumed that the expression
-"iterator1 + n" and "iterator1 - iterator2" has the semantics as
-described in current 25 [lib.algorithms], paragraph 9, but applying to
-all clauses. The expression "iterator1 - n" is equivalent to an
-result-iterator for which the expression "result-iterator + n" yields an
-iterator denoting the same position as iterator1 does. The terms
-"iterator1", "iterator2" and "result-iterator" shall denote the value of
-an iterator type, and the term "n" shall denote a value of a distance
-type between two iterators.
      
+Change 26.7.3 [partial.sum]/1 as indicated:
+
      
 
+
      
 
      
-All implementations known to the author of this Defect Report comply
-with these assumptions.
-No impact on current code is expected.
      
+Effects: Let VT be InputIterator's value type. For a nonempty range,
+initializes an accumulator acc of type VT with *first and performs
+*result = acc. For every iterator i in [first + 1, last) in order, acc is then
+modified by acc = acc + *i or acc = binary_op(acc, *i) and is assigned
+to *(result + (i - first)). Assigns to every element referred to by
+iterator i in the range [result,result + (last - first)) a value
+correspondingly
+equal to
+
      
 
-
      3) Proposed fixes:
      
+
      
+((...(*first + *(first + 1)) + ...) + *(first + (i - result)))
+
      
 
+
      
+or
+
      
 
-
      Change 25 [lib.algorithms], paragraph 9 to:
      
+
      
+binary_op(binary_op(...,
+   binary_op(*first, *(first + 1)),...), *(first + (i - result)))
+
      
+
      
+
      2. 
 
+
    2. 
 
      
-"In the description of the algorithms operator + and - are used for some
-of the iterator categories for which they do not have to be defined. In
-this paragraph, a and b denote values of an iterator type, and n denotes
-a value of a distance type between two iterators. In these cases the
-semantics of a+n is the same as that of
      
-
      {X tmp = a;
-advance(tmp, n);
-return tmp;
-}
-
      
-
      ,the semantics of a-n denotes the value of an iterator i for which the
-following condition holds:
-advance(i, n) == a,
-and that of b-a is the same as of
-return distance(a, b)".
+Change 26.7.3 [partial.sum]/3 as indicated:
 
      
 
-
      Comments to the new wording:
      
+
      
+Complexity: Exactly max((last - first) - 1, 0)
+applications
+of binary_opthe binary operation.
+
      
+
      3. 
 
+
    3. 
 
      
-a) The wording " In this paragraph, a and b denote values of an iterator
-type, and n denotes a value of a distance type between two iterators."
-was added so the expressions "b-a" and "a-n" are distinguished regarding
-the types of the values on which they operate.
-b) The wording ",the semantics of a-n denotes the value of an iterator i
-for which the following condition holds: advance(i, n) == a" was added
-to cover the expression 'iterator - n'. The wording "advance(i, n) == a"
-was used to avoid a dependency on the semantics of a+n, as the wording
-"i + n == a" would have implied. However, such a dependency might well
-be deserved.
-c) DR 225 is not considered in the new wording.
+Change 26.7.3 [partial.sum]/4 as indicated:
 
      
 
-
      
-Proposed fixes regarding invalid iterator arithmetic expressions outside
-clause 25:
      
+
      
+Requires: VT shall be constructible from the type of *first, the result of
+acc + *i or binary_op(acc, *i) shall be implicitly convertible to VT, and
+the result of the expression acc shall be writable to the result
+output iterator. In the ranges [first,last] and
+[result,result + (last - first)] [..]
+
      
+
      4. 
 
+
    4. 
 
      
-Either
-a) Move modified 25 [lib.algorithms], paragraph 9 (as proposed above)
-before any current invalid iterator arithmetic expression. In that case,
-the first sentence of 25 [lib.algorithms], paragraph 9, need also to be
-modified and could read: "For the rest of this International Standard,
-...." / "In the description of the following clauses including this
-...." / "In the description of the text below ..." etc. - anyways
-substituting the wording "algorithms", which is a straight reference to
-clause 25.
-In that case, 25 [lib.algorithms] paragraph 9 will certainly become
-obsolete.
-Alternatively,
-b) Add an appropiate paragraph similar to resolved 25 [lib.algorithms],
-paragraph 9, to the beginning of each clause containing invalid iterator
-arithmetic expressions.
-Alternatively,
-c) Fix each paragraph (both current wording and possible resolutions of
-DRs) containing invalid iterator arithmetic expressions separately.
+Change 26.7.4 [adjacent.difference]/1 as indicated:
 
      
 
-
      5) References to other DRs:
      
-
+
      
 
      
-See DR 225.
-See DR 237. The resolution could then also read "Linear in last -
-first".
+Effects: Let VT be InputIterator's value type. For a nonempty range,
+initializes an accumulator acc of type VT with *first and performs
+*result = acc. For every iterator i in [first + 1, last) in order,
+initializes a
+value val of type VT with *i, assigns the result of val - acc or
+binary_op(val, acc)
+to *(result + (i - first)) and modifies acc = std::move(val).
+Assigns to every element referred to by iterator i in the range
+[result + 1,
+result + (last - first)) a value correspondingly equal to
 
      
 
-
      [
-Bellevue:
-]
      
+
      
+*(first + (i - result)) - *(first + (i - result) - 1)
+
      
 
+
      
+or
+
      
 
-
      
-Keep open and ask Bill to provide wording.
-
      
+
      
+binary_op(*(first + (i - result)), *(first + (i - result) - 1)).
+
      
 
-
      [
-2009-05-09 Alisdair adds:
-]
      
+
      
+result gets the value of *first.
+
      
+
      
+
      5. 
 
+
    5. 
+
      
+Change 26.7.4 [adjacent.difference]/2 as indicated:
+
      
 
 
      
-This issue is related to 997.
+Requires: VT shall be MoveAssignable ([moveassignable])
+and shall be
+constructible from the type of *first. The result
+of the expression acc and the result of the expression val - acc or
+binary_op(val, acc)
+shall be writable to the result output iterator. In the ranges
+[first,last] [..]
 
      
+
      6. 
 
+
    6. 
+
      
+Change 26.7.4 [adjacent.difference]/5 as indicated:
+
      
 
+
      
+Complexity: Exactly max((last - first) - 1, 0)
+applications
+of binary_opthe binary operation.
+
      
+
      7. 
+
    
 
-
    Proposed resolution:
    
-
-
    [Lillehammer: Minor issue, but real. We have a blanket statement
-about this in 25/11. But (a) it should be in 17, not 25; and (b) it's
-not quite broad enough, because there are some arithmetic expressions
-it doesn't cover. Bill will provide wording.]
    
 
 
 
@@ -5185,127 +4158,79 @@ it doesn't cover. Bill will provide wording.]
    
 
 
 
    
-
    498. Requirements for partition() and stable_partition() too strong
    
-
    Section: 25.4.13 [alg.partitions] Status: Open
- Submitter: Sean Parent, Joe Gottman Opened: 2005-05-04  Last modified: 2009-05-01
    
+
    556. is Compare a BinaryPredicate?
    
+
    Section: 25.5 [alg.sorting] Status: Open
+ Submitter: Martin Sebor Opened: 2006-02-05  Last modified: 2009-07-28
    
+
    View all other issues in [alg.sorting].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-Problem:
-The iterator requirements for partition() and stable_partition() [25.2.12]
-are listed as BidirectionalIterator, however, there are efficient algorithms
-for these functions that only require ForwardIterator that have been known
-since before the standard existed. The SGI implementation includes these (see
-http://www.sgi.com/tech/stl/partition.html
-and
-http://www.sgi.com/tech/stl/stable_partition.html).
+In 25, p8 we allow BinaryPredicates to return a type that's convertible
+to bool but need not actually be bool. That allows predicates to return
+things like proxies and requires that implementations be careful about
+what kinds of expressions they use the result of the predicate in (e.g.,
+the expression in if (!pred(a, b)) need not be well-formed since the
+negation operator may be inaccessible or return a type that's not
+convertible to bool).
+
    
+
    
+Here's the text for reference:
+
    
+
    
+  ...if an algorithm takes BinaryPredicate binary_pred as its argument
+ and first1 and first2 as its iterator arguments, it should work
+ correctly in the construct if (binary_pred(*first1, first2)){...}.
+
    
+
+
    
+In 25.3, p2 we require that the Compare function object return true
+of false, which would seem to preclude such proxies. The relevant text
+is here:
 
    
+
    
+  Compare is used as a function object which returns true if the first
+  argument is less than the second, and false otherwise...
+
    
 
 
    [
-2009-04-30 Alisdair adds:
+2009-07-28 Reopened by Alisdair.  No longer solved by concepts.
 ]
    
 
 
-
    
-
    
-Now we have concepts this is easier to express!
-
    
-
    
-Proposed resolution:
-
    
-
    
-Add the following signature to:
-
    
-
    
-Header <algorithm> synopsis 25.2 [algorithms.syn]
    
-p3 Partitions 25.4.13 [alg.partitions]
-
    
-
     template<ForwardIterator Iter, Predicate<auto, Iter::value_type> Pred>
-   requires ShuffleIterator<Iter>
-         && CopyConstructible<Pred>
-   Iter partition(Iter first, Iter last, Pred pred);
-
    
-
-
    
-Update p3 Partitions 25.4.13 [alg.partitions]:
-
    
-
-
    
-
    
-Complexity: At most (last - first)/2 swaps. Exactly last - first
-applications of the predicate
-are done.
-
-If Iter satisfies BidirectionalIterator, at most (last -
-first)/2 swaps. Exactly last - first applications of the predicate
-are done.
-
-
    
-
    
-If Iter merely satisfied ForwardIterator at most (last - first) swaps
-are done. Exactly (last - first) applications of the predicate are done.
-
    
-
    
-
-
    
-[Editorial note: I looked for existing precedent in how we might call out
-distinct overloads overloads from a set of constrained templates, but there
-is not much existing practice to lean on.   advance/distance were the only
-algorithms I could find, and that wording is no clearer.]
-
    
-
-
    
-
 
 
 
    Proposed resolution:
    
 
    
-Change 25.2.12 from 
    
-
    template<class BidirectionalIterator, class Predicate> 
-BidirectionalIterator partition(BidirectionalIterato r first, 
-                                BidirectionalIterator last, 
-                                Predicate pred); 
-
    
-
    to 
    
-
    template<class ForwardIterator, class Predicate> 
-ForwardIterator partition(ForwardIterator first, 
-                          ForwardIterator last, 
-                          Predicate pred); 
-
    
-
    Change the complexity from 
    
-
+I think we could fix this by rewording 25.3, p2 to read somthing like:
+
    
 
    
-At most (last - first)/2 swaps are done. Exactly (last - first) 
-applications of the predicate are done. 
+-2- Compare is used as a function object which returns
+true if the first argument a BinaryPredicate. The
+return value of the function call operator applied to an object of type
+Compare, when converted to type bool, yields true
+if the first argument of the call is less than the second, and
+false otherwise. Compare comp is used throughout for
+algorithms assuming an ordering relation. It is assumed that comp
+will not apply any non-constant function through the dereferenced iterator.
 
    
 
-
    to 
    
-
-
    
-If ForwardIterator is a bidirectional_iterator, at most (last - first)/2 
-swaps are done; otherwise at most (last - first) swaps are done. Exactly 
-(last - first) applications of the predicate are done. 
-
    
 
+
    [
+Portland:  Jack to define "convertible to bool" such that short circuiting isn't
+destroyed.
+]
    
 
 
 
    Rationale:
    
-
    
-Partition is a "foundation" algorithm useful in many contexts (like sorting
-as just one example) - my motivation for extending it to include forward
-iterators is foward_list - without this extension you can't partition an foward_list
-(without writing your own partition). Holes like this in the standard
-library weaken the argument for generic programming (ideally I'd be able
-to provide a library that would refine std::partition() to other concepts
-without fear of conflicting with other libraries doing the same - but
-that is a digression). I consider the fact that partition isn't defined
-to work for ForwardIterator a minor embarrassment.
-
    
+
    [
+San Francisco:
+]
    
 
-
    [Mont Tremblant: Moved to Open, request motivation and use cases
-by next meeting. Sean provided further rationale by post-meeting
-mailing.]
    
 
+
    
+Solved by
+(N2774).
+
    
 
 
 
@@ -5313,496 +4238,504 @@ mailing.]
    
 
 
 
    
-
    502. Proposition: Clarification of the interaction between a facet and an iterator
    
-
    Section: 22.3.1.1.1 [locale.category] Status: Open
- Submitter: Christopher Conrade Zseleghovski Opened: 2005-06-07  Last modified: 2008-03-13
    
-
    View all other issues in [locale.category].
    
-
    View all issues with Open status.
    
+
    564. stringbuf seekpos underspecified
    
+
    Section: 27.8.1.4 [stringbuf.virtuals] Status: Ready
+ Submitter: Martin Sebor Opened: 2006-02-23  Last modified: 2009-07-15
    
+
    View all other issues in [stringbuf.virtuals].
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
 
    
-Motivation:
+The   effects  of  the   seekpos()  member   function  of
+basic_stringbuf  simply say  that the  function positions
+the  input and/or  output  sequences  but fail  to  spell out  exactly
+how. This is in contrast  to the detail in which seekoff()
+is described.
 
    
 
-
    
-This requirement seems obvious to me, it is the essence of code modularity. 
-I have complained to Mr. Plauger that the Dinkumware library does not 
-observe this principle but he objected that this behaviour is not covered in 
-the standard.
-
    
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+Move to Ready.
+
    
+
 
 
 
    Proposed resolution:
    
-
    
-Append the following point to 22.1.1.1.1:
-
    
+        
    
+
+Change 27.7.1.3, p13 to read:
 
+        
    
+
    
 
    
-6. The implementation of a facet of Table 52 parametrized with an 
-InputIterator/OutputIterator should use that iterator only as character 
-source/sink respectively.
-For a *_get facet, it means that the value received depends only on the 
-sequence of input characters and not on how they are accessed.
-For a *_put facet, it means that the sequence of characters output depends 
-only on the value to be formatted and not of how the characters are stored.
+-13- Effects: Equivalent to seekoff(off_type(sp), ios_base::beg,
+which). Alters the stream position within the controlled sequences,
+if possible, to correspond to the stream position stored in sp
+(as described below).
 
    
+
      
+
    • If (which & ios_base::in) != 0, positions the input sequence.
      • 
+
    • If (which & ios_base::out) != 0, positions the output sequence.
      • 
+
    • If sp is an invalid stream position, or if the function
+positions neither sequence, the positioning operation fails. If sp
+has not been obtained by a previous successful call to one of the positioning
+functions (seekoff, seekpos, tellg, tellp)
+the effect is undefined.
      • 
+
    
+
    
+
 
 
    [
-Berlin:  Moved to Open, Need to clean up this area to make it clear
-locales don't have to contain open ended sets of facets. Jack, Howard,
-Bill.
+Kona (2007): A pos_type is a position in a stream by
+definition, so there is no ambiguity as to what it means. Proposed
+Disposition: NAD
 ]
    
 
 
+
    [
+Post-Kona Martin adds:
+I'm afraid I disagree
+with the Kona '07 rationale for marking it NAD. The only text
+that describes precisely what it means to position the input
+or output sequence is in seekoff(). The seekpos() Effects
+clause is inadequate in comparison and the proposed resolution
+plugs the hole by specifying seekpos() in terms of seekoff().
+]
    
 
 
 
 
 
 
    
-
    503. more on locales
    
-
    Section: 22.4 [locale.categories] Status: Open
- Submitter: P.J. Plauger Opened: 2005-06-20  Last modified: 2008-03-13
    
-
    View other active issues in [locale.categories].
    
-
    View all other issues in [locale.categories].
    
-
    View all issues with Open status.
    
+
    565. xsputn inefficient
    
+
    Section: 27.6.2.4.5 [streambuf.virt.put] Status: Ready
+ Submitter: Martin Sebor Opened: 2006-02-23  Last modified: 2009-07-15
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
-
    
-a) In 22.2.1.1 para. 2 we refer to "the instantiations required in Table
-51" to refer to the facet *objects* associated with a locale. And we
-almost certainly mean just those associated with the default or "C"
-locale. Otherwise, you can't switch to a locale that enforces a different
-mapping between narrow and wide characters, or that defines additional
-uppercase characters.
-
    
+        
    
 
-
    
-b) 22.2.1.5 para. 3 (codecvt) has the same issues.
-
    
+streambuf::xsputn()  is  specified  to  have  the  effect  of
+"writing up to  n characters to the output  sequence as if by
+repeated calls to sputc(c)."
 
-
    
-c) 22.2.1.5.2 (do_unshift) is even worse. It *forbids* the generation of
-a homing sequence for the basic character set, which might very well need
-one.
-
    
+        
    
+        
    
 
-
    
-d) 22.2.1.5.2 (do_length) likewise dictates that the default mapping
-between wide and narrow characters be taken as one-for-one.
-
    
+Since  sputc() is required  to call  overflow() when
+(pptr()    ==   epptr())    is   true,    strictly   speaking
+xsputn()  should do  the same.   However, doing  so  would be
+suboptimal in  some interesting cases,  such as in unbuffered  mode or
+when the buffer is basic_stringbuf.
 
-
    
-e) 22.2.2 para. 2 (num_get/put) is both muddled and vacuous, as far as
-I can tell. The muddle is, as before, calling Table 51 a list of
-instantiations. But the constraint it applies seems to me to cover
-*all* defined uses of num_get/put, so why bother to say so?
-
    
+        
    
+        
    
 
-
    
-f) 22.2.3.1.2 para. 1(do_decimal_point) says "The required instantiations
-return '.' or L'.'.) Presumably this means "as appropriate for the
-character type. But given the vague definition of "required" earlier,
-this overrules *any* change of decimal point for non "C" locales.
-Surely we don't want to do that.
-
    
+Assuming  calling overflow()  is  not really  intended to  be
+required  and the  wording is  simply  meant to  describe the  general
+effect of appending to the end  of the sequence it would be worthwhile
+to  mention in  xsputn() that  the function  is  not actually
+required to cause a call to overflow().
 
-
    
-g) 22.2.3.1.2 para. 2 (do_thousands_sep) says "The required instantiations
-return ',' or L','.) As above, this probably means "as appropriate for the
-character type. But this overrules the "C" locale, which requires *no*
-character ('\0') for the thousands separator. Even if we agree that we
-don't mean to block changes in decimal point or thousands separator,
-we should also eliminate this clear incompatibility with C.
-
    
+        
    
 
-
    
-h) 22.2.3.1.2 para. 2 (do_grouping) says "The required instantiations
-return the empty string, indicating no grouping." Same considerations
-as for do_decimal_point.
-
    
+
    [
+2009-07 Frankfurt
+]
    
 
-
    
-i) 22.2.4.1 para. 1 (collate) refers to "instantiations required in Table
-51". Same bad jargon.
-
    
 
-
    
-j) 22.2.4.1.2 para. 1 (do_compare) refers to "instantiations required
-in Table 51". Same bad jargon.
-
    
+
    
+Move to Ready.
+
    
 
-
    
-k) 22.2.5 para. 1 (time_get/put) uses the same muddled and vacuous
-as num_get/put.
-
    
 
-
    
-l) 22.2.6 para. 2 (money_get/put) uses the same muddled and vacuous
-as num_get/put.
-
    
 
-
    
-m) 22.2.6.3.2 (do_pos/neg_format) says "The instantiations required
-in Table 51 ... return an object of type pattern initialized to
-{symbol, sign, none, value}." This once again *overrides* the "C"
-locale, as well as any other locale."
-
    
+
    Proposed resolution:
    
+        
    
 
-
    
-3) We constrain the use_facet calls that can be made by num_get/put,
-so why don't we do the same for money_get/put? Or for any of the
-other facets, for that matter?
-
    
+Add the following sentence  to the xsputn() Effects clause in
+27.5.2.4.5, p1 (N1804):
 
-
    
-4) As an almost aside, we spell out when a facet needs to use the ctype
-facet, but several also need to use a codecvt facet and we don't say so.
-
    
-
    [
-Berlin: Bill to provide wording.
-]
    
+        
    
+        
        
+            
    
+-1- Effects: Writes up to n characters to the output
+sequence as if by repeated calls to sputc(c). The characters 
+written are obtained from successive elements of the array whose first element
+is designated by s. Writing stops when either n
+characters have been written or a call to sputc(c) would return
+traits::eof(). It is  uspecified whether the function  calls
+overflow() when (pptr() ==  epptr()) becomes true or whether
+it achieves the same effects by other means.
+            
    
+        
        
+        
    
 
+In addition,  I suggest to  add a footnote  to this function  with the
+same text as Footnote 292 to  make it extra clear that derived classes
+are permitted to override xsputn() for efficiency.
 
+        
    
 
-
    Proposed resolution:
    
-
    
-
    
+
+
    [
+Kona (2007): We want to permit a streambuf that streams output directly
+to a device without making calls to sputc or overflow. We believe that
+has always been the intention of the committee. We believe that the
+proposed wording doesn't accomplish that. Proposed Disposition: Open
+]
    
 
 
 
 
 
 
    
-
    523. regex case-insensitive character ranges are unimplementable as specified
    
-
    Section: 28 [re] Status: Open
- Submitter: Eric Niebler Opened: 2005-07-01  Last modified: 2008-03-13
    
-
    View other active issues in [re].
    
-
    View all other issues in [re].
    
+
    580. unused allocator members
    
+
    Section: 23.2.1 [container.requirements.general] Status: Open
+ Submitter: Martin Sebor Opened: 2006-06-14  Last modified: 2009-07-15
    
+
    View other active issues in [container.requirements.general].
    
+
    View all other issues in [container.requirements.general].
    
 
    View all issues with Open status.
    
+
    Duplicate of: 479
    
 
    Discussion:
    
-
    
-A problem with TR1 regex is currently being discussed on the Boost 
-developers list. It involves the handling of case-insensitive matching 
-of character ranges such as [Z-a]. The proper behavior (according to the 
-ECMAScript standard) is unimplementable given the current specification 
-of the TR1 regex_traits<> class template. John Maddock, the author of 
-the TR1 regex proposal, agrees there is a problem. The full discussion 
-can be found at http://lists.boost.org/boost/2005/06/28850.php (first 
-message copied below). We don't have any recommendations as yet.
-
    
-
    
--- Begin original message --
-
    
-
    
-The situation of interest is described in the ECMAScript specification
-(ECMA-262), section 15.10.2.15:
-
    
-
    
-"Even if the pattern ignores case, the case of the two ends of a range
-is significant in determining which characters belong to the range.
-Thus, for example, the pattern /[E-F]/i matches only the letters E, F,
-e, and f, while the pattern /[E-f]/i matches all upper and lower-case
-ASCII letters as well as the symbols [, \, ], ^, _, and `."
-
    
-
    
-A more interesting case is what should happen when doing a
-case-insentitive match on a range such as [Z-a]. It should match z, Z,
-a, A and the symbols [, \, ], ^, _, and `. This is not what happens with
-Boost.Regex (it throws an exception from the regex constructor).
-
    
-
    
-The tough pill to swallow is that, given the specification in TR1, I
-don't think there is any effective way to handle this situation.
-According to the spec, case-insensitivity is handled with
-regex_traits<>::translate_nocase(CharT) -- two characters are equivalent
-if they compare equal after both are sent through the translate_nocase
-function. But I don't see any way of using this translation function to
-make character ranges case-insensitive. Consider the difficulty of
-detecting whether "z" is in the range [Z-a]. Applying the transformation
-to "z" has no effect (it is essentially std::tolower). And we're not
-allowed to apply the transformation to the ends of the range, because as
-ECMA-262 says, "the case of the two ends of a range is significant."
-
    
-
    
-So AFAICT, TR1 regex is just broken, as is Boost.Regex. One possible fix
-is to redefine translate_nocase to return a string_type containing all
-the characters that should compare equal to the specified character. But
-this function is hard to implement for Unicode, and it doesn't play nice
-with the existing ctype facet. What a mess!
-
    
-
    
--- End original message --
-
    
+        
    
 
-
    [
-John Maddock adds:
-]
    
+C++ Standard Library  templates that take an allocator  as an argument
+are    required    to    call    the    allocate()    and
+deallocate()  members of the  allocator object  to obtain
+storage.  However, they do not appear to be required to call any other
+allocator      members      such     as      construct(),
+destroy(),           address(),          and
+max_size().  This makes these allocator members less than
+useful in portable programs.
 
+        
    
+        
    
 
-
    
-One small correction, I have since found that ICU's regex package does 
-implement this correctly, using a similar mechanism to the current 
-TR1.Regex.
-
    
-
    
-Given an expression [c1-c2] that is compiled as case insensitive it:
-
    
-
    
-Enumerates every character in the range c1 to c2 and converts it to it's 
-case folded equivalent.  That case folded character is then used a key to a 
-table of equivalence classes, and each member of the class is added to the 
-list of possible matches supported by the character-class.  This second step 
-isn't possible with our current traits class design, but isn't necessary if 
-the input text is also converted to a case-folded equivalent on the fly.
-
    
-
    
-ICU applies similar brute force mechanisms to character classes such as 
-[[:lower:]] and [[:word:]], however these are at least cached, so the impact 
-is less noticeable in this case.
-
    
-
    
-Quick and dirty performance comparisons show that expressions such as 
-"[X-\\x{fff0}]+" are indeed very slow to compile with ICU (about 200 times 
-slower than a "normal" expression).  For an application that uses a lot of 
-regexes this could have a noticeable performance impact.  ICU also has an 
-advantage in that it knows the range of valid characters codes: code points 
-outside that range are assumed not to require enumeration, as they can not 
-be part of any equivalence class.  I presume that if we want the TR1.Regex 
-to work with arbitrarily large character sets enumeration really does become 
-impractical.
-
    
-
    
-Finally note that Unicode has:
-
    
-
    
-Three cases (upper, lower and title).
-One to many, and many to one case transformations.
-Character that have context sensitive case translations - for example an 
-uppercase sigma has two different lowercase forms  - the form chosen depends 
-on context(is it end of a word or not), a caseless match for an upper case 
-sigma should match either of the lower case forms, which is why case folding 
-is often approximated by tolower(toupper(c)).
-
    
-
    
-Probably we need some way to enumerate character equivalence classes, 
-including digraphs (either as a result or an input), and some way to tell 
-whether the next character pair is a valid digraph in the current locale.
-
    
-
    
-Hoping this doesn't make this even more complex that it was already,
-
    
+It's unclear to me whether the absence of the requirement to use these
+allocator  members  is  an  unintentional  omission  or  a  deliberate
+choice. However,  since the functions exist in  the standard allocator
+and  since  they are  required  to  be  provided by  any  user-defined
+allocator I  believe the standard  ought to be clarified  to explictly
+specify  whether programs  should or  should not  be able  to  rely on
+standard containers calling the functions.
+
+        
    
+        
    
+
+I  propose  that all  containers  be required  to  make  use of  these
+functions.
+
+        
    
+
    [
+Batavia:  We support this resolution.  Martin to provide wording.
+]
    
 
 
    [
-Portland:  Alisdair: Detect as invalid, throw an exception.
-Pete: Possible general problem with case insensitive ranges.
+pre-Oxford:  Martin provided wording.
 ]
    
 
 
+
    [
+2009-04-28 Pablo adds:
+]
    
 
 
-
    Proposed resolution:
    
+
    
+N2554
+(scoped allocators),
+N2768
+(allocator concepts), and
+N2810
+(allocator defects), address all of these points EXCEPT max_size().
+So, I would add a note to that affect and re-class the defect as belonging
+to section 23.2.1 [container.requirements.general].
+
    
 
+
    [
+2009-07 Frankfurt
+]
    
 
 
+
    
+The comment in the description of this issue that this "would be"
+rendered editorial by the adoption of N2257 is confusing. It appears
+that N2257 was never adopted.
+
    
 
 
-
    
-
    539. partial_sum and adjacent_difference should mention requirements
    
-
    Section: 26.7.3 [partial.sum] Status: Open
- Submitter: Marc Schoolderman Opened: 2006-02-06  Last modified: 2009-05-10
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    
-There are some problems in the definition of partial_sum and
-adjacent_difference in 26.4 [lib.numeric.ops]
-
    
 
-
    
-Unlike accumulate and inner_product, these functions are not
-parametrized on a "type T", instead, 26.4.3 [lib.partial.sum] simply
-specifies the effects clause as;
-
    
+    
    Proposed resolution:
    
+       
    
 
-
    
-Assigns to every element referred to by iterator i in the range
-[result,result + (last - first)) a value correspondingly equal to
-
    
-
    ((...(* first + *( first + 1)) + ...) + *( first + ( i - result )))
-
    
-
    
+Specifically, I propose to change 23.2 [container.requirements],
+p9 as follows:
 
+       
    
+           
    
 
    
-And similarly for BinaryOperation. Using just this definition, it seems
-logical to expect that:
-
    
+-9- Copy constructors  for all container types defined  in this clause
+that   are  parametrized  on   Allocator  copy
+anthe  allocator argument from  their respective
+first parameters.
 
+All other  constructors for  these container types  take an
+const  Allocator&  argument  (20.1.6),  an
+allocator whose value_type is the same as the container's
+value_type.
 
-
    char i_array[4] = { 100, 100, 100, 100 };
-int  o_array[4];
+A copy of this  argument isshall be used for any
+memory  allocation  and  deallocation performed,
+by these  constructors and by all  member functions, during
+the  lifetime  of each  container  object.   Allocation shall  be
+performed  "as  if"  by  calling  the  allocate()  member
+function on  a copy  of the allocator  object of the  appropriate type
+New  Footnote),   and  deallocation  "as   if"  by  calling
+deallocate() on  a copy of  the same allocator  object of
+the corresponding type.
 
-std::partial_sum(i_array, i_array+4, o_array);
-
    
+A  copy of  this argument  shall also  be used  to  construct and
+destroy objects whose lifetime  is managed by the container, including
+but not  limited to those of  the container's value_type,
+and  to  obtain  their  address.   All  objects  residing  in  storage
+allocated by a  container's allocator shall be constructed  "as if" by
+calling the construct() member  function on a copy of the
+allocator object of  the appropriate type.  The same  objects shall be
+destroyed "as if"  by calling destroy() on a  copy of the
+same allocator object  of the same type.  The  address of such objects
+shall be obtained "as if" by calling the address() member
+function  on  a  copy  of  the allocator  object  of  the  appropriate
+type.
 
+Finally, a copy  of this argument shall be  used by its container
+object to determine  the maximum number of objects  of the container's
+value_type the container may  store at the same time. The
+container  member function max_size() obtains  this number
+from      the      value      returned      by     a      call      to
+get_allocator().max_size().
+
+In   all  container   types  defined   in  this   clause that  are
+parametrized     on    Allocator,     the    member
+get_allocator()     returns     a     copy     of     the
+Allocator     object     used     to    construct     the
+container.258)
+
    
 
    
-Is equivalent to
+New Footnote: This type  may be different from Allocator:
+it     may    be     derived    from     Allocator    via
+Allocator::rebind<U>::other   for  the  appropriate
+type U.
 
    
+           
    
+       
    
 
-
    int o_array[4] = { 100, 100+100, 100+100+100, 100+100+100+100 };
-
    
+The proposed wording seems cumbersome but I couldn't think of a better
+way   to  describe   the   requirement  that   containers  use   their
+Allocator  to manage  only objects  (regardless  of their
+type)  that  persist  over  their  lifetimes  and  not,  for  example,
+temporaries  created on the  stack. That  is, containers  shouldn't be
+required  to  call  Allocator::construct(Allocator::allocate(1),
+elem)  just to  construct a  temporary copy  of an  element, or
+Allocator::destroy(Allocator::address(temp),     1)    to
+destroy temporaries.
 
-
    
-i.e. 100, 200, 300, 400, with addition happening in the result type,
-int.
-
    
+       
    
 
-
    
-Yet all implementations I have tested produce 100, -56, 44, -112,
-because they are using an accumulator of the InputIterator's
-value_type, which in this case is char, not int.
-
    
 
-
    
-The issue becomes more noticeable when the result of the expression *i +
-*(i+1) or binary_op(*i, *i-1) can't be converted to the
-value_type. In a contrived example:
-
    
+
    [
+Howard: This same paragraph will need some work to accommodate 431.
+]
    
 
-
    enum not_int { x = 1, y = 2 };
-...
-not_int e_array[4] = { x, x, y, y };
-std::partial_sum(e_array, e_array+4, o_array);
-
    
 
-
    
-Is it the intent that the operations happen in the input type, or in
-the result type?
-
    
+
    [
+post Oxford:  This would be rendered NAD Editorial by acceptance of
+N2257.
+]
    
 
-
    
-If the intent is that operations happen in the result type, something
-like this should be added to the "Requires" clause of 26.4.3/4
-[lib.partial.sum]:
-
    
 
-
    
-The type of *i + *(i+1) or binary_op(*i, *(i+1)) shall meet the
-requirements of CopyConstructible (20.1.3) and Assignable
-(23.1) types.
-
    
 
-
    
-(As also required for T in 26.4.1 [lib.accumulate] and 26.4.2
-[lib.inner.product].)
-
    
 
+
+
    
+
    588. requirements on zero sized tr1::arrays and other details
    
+
    Section: 23.3.1 [array] Status: Tentatively NAD
+ Submitter: Gennaro Prota Opened: 2006-07-18  Last modified: 2009-07-15
    
+
    View other active issues in [array].
    
+
    View all other issues in [array].
    
+
    View all issues with Tentatively NAD status.
    
+
    Discussion:
    
 
    
-The "auto initializer" feature proposed in
-N1894
-is not required to
-implement partial_sum this way. The 'narrowing' behaviour can still be
-obtained by using the std::plus<> function object.
+The wording used for section 23.2.1 [lib.array] seems to be subtly
+ambiguous about zero sized arrays (N==0). Specifically:
 
    
-
 
    
-If the intent is that operations happen in the input type, then
-something like this should be added instead;
+* "An instance of array<T, N> stores N elements of type T, so that
+[...]"
 
    
-
-
    
-The type of *first shall meet the requirements of
-CopyConstructible (20.1.3) and Assignable (23.1) types.
-The result of *i + *(i+1) or binary_op(*i, *(i+1)) shall be
-convertible to this type.
-
    
-
 
    
-The 'widening' behaviour can then be obtained by writing a custom proxy
-iterator, which is somewhat involved.
+Does this imply that a zero sized array object stores 0 elements, i.e.
+that it cannot store any element of type T? The next point clarifies
+the rationale behind this question, basically how to implement begin()
+and end():
 
    
-
 
    
-In both cases, the semantics should probably be clarified.
+* 23.2.1.5 [lib.array.zero], p2: "In the case that N == 0, begin() ==
+end() == unique value."
 
    
-
 
    
-26.4.4 [lib.adjacent.difference] is similarly underspecified, although
-all implementations seem to perform operations in the 'result' type:
+What does "unique" mean in this context? Let's consider the following
+possible implementations, all relying on a partial specialization:
 
    
+
    a)
+    template< typename T >
+    class array< T, 0 > {
+    
+        ....
 
-
    unsigned char i_array[4] = { 4, 3, 2, 1 };
-int o_array[4];
+        iterator begin()
+        { return iterator( reinterpret_cast< T * >( this ) ); }
+        ....
 
-std::adjacent_difference(i_array, i_array+4, o_array);
+    };
 
    
-
 
    
-o_array is 4, -1, -1, -1 as expected, not 4, 255, 255, 255.
+This has been used in boost, probably intending that the return value
+had to be unique to the specific array object and that array couldn't
+store any T. Note that, besides relying on a reinterpret_cast, has
+(more than potential) alignment problems.
 
    
+
    b)
+    template< typename T >
+    class array< T, 0 > {
+    
+        T t;
+
+        iterator begin()
+        { return iterator( &t ); }
+        ....
 
+    };
+
    
 
    
-In any case, adjacent_difference doesn't mention the requirements on the
-value_type; it can be brought in line with the rest of 26.4
-[lib.numeric.ops] by adding the following to 26.4.4/2
-[lib.adjacent.difference]:
+This provides a value which is unique to the object and to the type of
+the array, but requires storing a T. Also, it would allow the user to
+mistakenly provide an initializer list with one element.
+
    
+
    
+A slight variant could be returning *the* null pointer of type T
+
    
+
        return static_cast<T*>(0);
+
    
+
    
+In this case the value would be unique to the type array<T, 0> but not
+to the objects (all objects of type array<T, 0> with the same value
+for T would yield the same pointer value).
+
    
+
    
+Furthermore this is inconsistent with what the standard requires from
+allocation functions (see library issue 9).
+
    
+
    
+c) same as above but with t being a static data member; again, the
+value would be unique to the type, not to the object.
+
    
+
    
+d) to avoid storing a T *directly* while disallowing the possibility
+to use a one-element initializer list a non-aggregate nested class
+could be defined
+
    
+
        struct holder { holder() {} T t; } h;
+
    
+
    
+and then begin be defined as
+
    
+
     iterator begin() { return &h.t; }
+
    
+
    
+But then, it's arguable whether the array stores a T or not.
+Indirectly it does.
+
    
+
    
+-----------------------------------------------------
+
    
+
    
+Now, on different issues:
+
    
+
    
+* what's the effect of calling assign(T&) on a zero-sized array? There
+seems to be only mention of front() and back(), in 23.2.1 [lib.array]
+p4 (I would also suggest to move that bullet to section 23.2.1.5
+[lib.array.zero], for locality of reference)
+
    
+
    
+* (minor) the opening paragraph of 23.2.1 [lib.array] wording is a bit
+inconsistent with that of other sequences: that's not a problem in
+itself, but compare it for instance with "A vector is a kind of
+sequence that supports random access iterators"; though the intent is
+obvious one might argue that the wording used for arrays doesn't tell
+what an array is, and relies on the reader to infer that it is what
+the <array> header defines.
+
    
+
    
+* it would be desiderable to have a static const data member of type
+std::size_t, with value N, for usage as integral constant expression
+
    
+
    
+* section 23.1 [lib.container.requirements] seem not to consider
+fixed-size containers at all, as it says: "[containers] control
+allocation and deallocation of these objects [the contained objects]
+through constructors, destructors, *insert and erase* operations"
+
    
+
    
+* max_size() isn't specified: the result is obvious but, technically,
+it relies on table 80: "size() of the largest possible container"
+which, again, doesn't seem to consider fixed size containers
 
    
-
-
    
-The type of *first shall meet the requirements of
-CopyConstructible (20.1.3) and Assignable (23.1) types."
-
    
-
    [
-Berlin: Giving output iterator's value_types very controversial. Suggestion of
-adding signatures to allow user to specify "accumulator".
-]
    
-
 
 
    [
-Bellevue:
+2009-05-29 Daniel adds:
 ]
    
 
 
 
    
-The intent of the algorithms is to perform their calculations using the type of the input iterator.
-Proposed wording provided.
+
      
+
    1. 
+
      
+star bullet 1 ("what's the effect of calling assign(T&) on a
+zero-sized array?[..]");
+
      
+
      
+assign has been renamed to fill and the semantic of fill is now
+defined in terms of
+the free algorithm fill_n, which is well-defined for this situation.
 
      
-
-
      [
-Sophia Antipolis:
-]
      
-
-
+
      2. 
+
    2. 
+
      
+star bullet 3 ("it would be desiderable to have a static const data
+member..."):
+
      
 
      
-We did not agree that the proposed resolution was correct. For example,
-when the arguments are types (float*, float*, double*), the
-highest-quality solution would use double as the type of the
-accumulator. If the intent of the wording is to require that the type of
-the accumulator must be the input_iterator's value_type, the wording
-should specify it.
+It seems that tuple_size<array<T, N> >::value as of 23.3.1.7 [array.tuple] does
+provide this functionality now.
+
      
+
      3. 
+
    
 
    
 
 
    [
-2009-05-09 Alisdair adds:
+2009-07 Frankfurt
 ]
    
 
 
 
    
 
    
-Now that we have the facility, the 'best' accumulator type could probably be
-deduced as:
-
    
-
    std::common_type<InIter::value_type, OutIter::reference>::type
-
    
-
    
-This type would then have additional requirements of constructability and
-incrementability/assignability.
+Alisdair to address by the next meeting, or declare NAD.
 
    
 
    
-If this extracting an accumulator type from a pair/set of iterators (with
-additional requirements on that type) is a problem for multiple functions,
-it might be worth extracting into a SharedAccumulator concept or similar.
-
    
-
    
-I'll go no further in writing up wording now, until the group gives a
-clearer indication of preferred direction.
+Moved to Tentatively NAD.
 
    
 
    
 
@@ -5810,217 +4743,285 @@ clearer indication of preferred direction.
 
 
    Proposed resolution:
    
 
    
-Add to section 26.7.3 [partial.sum] paragraph 4 the following two sentences:
-
    
-
-
    
-The type of *first shall meet the requirements of CopyConstructible?
-(20.1.3?) and Assignable (23.1?) types. The result of *i + *(i+1) or
-binary_op(*i, *(i+1)) shall be convertible to this type.
-
    
-
-
    
-Add to section 26.7.4 [adjacent.difference] paragraph 2 the following sentence:
 
    
 
-
    
-The type of *first shall meet the requirements of CopyConstructible?
-(20.1.3) and Assignable (23.1) types.
-
    
 
+
    [
+Kona (2007): requirements on zero sized tr1::arrays and other details
+Issue 617: std::array is a sequence that doesn't satisfy the sequence
+requirements? Alisdair will prepare a paper. Proposed Disposition: Open
+]
    
 
 
 
 
 
 
    
-
    546. _Longlong and _ULonglong are integer types
    
-
    Section: TR1 5.1.1 [tr.rand.req] Status: Open
- Submitter: Matt Austern Opened: 2006-01-10  Last modified: 2007-10-09
    
+
    594. Disadvantages of defining Swappable in terms of CopyConstructible and Assignable
    
+
    Section: X [utility.arg.requirements] Status: Open
+ Submitter: Niels Dekker Opened: 2006-11-02  Last modified: 2009-07-26
    
+
    View other active issues in [utility.arg.requirements].
    
+
    View all other issues in [utility.arg.requirements].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-The TR sneaks in two new integer types, _Longlong and _Ulonglong, in [tr.c99].
-The rest of the TR should use that type.  I believe this affects two places.
-First, the random number requirements, 5.1.1/10-11, lists all of the types with
-which template parameters named IntType and UIntType may be instantiated.
-_Longlong (or "long long", assuming it is added to C++0x) should be added to the
-IntType list, and UIntType (again, or "unsigned long long") should be added to
-the UIntType list.  Second, 6.3.2 lists the types for which hash<> is
-required to be instantiable. _Longlong and _Ulonglong should be added to that
-list, so that people may use long long as a hash key.
+It seems undesirable to define the Swappable requirement in terms of
+CopyConstructible and Assignable requirements. And likewise, once the
+MoveConstructible and MoveAssignable requirements (N1860) have made it
+into the Working Draft, it seems undesirable to define the Swappable
+requirement in terms of those requirements. Instead, it appears
+preferable to have the Swappable requirement defined exclusively in
+terms of the existence of an appropriate swap function.
 
    
-
-
-
    Proposed resolution:
    
 
    
+Section 20.1.4 [lib.swappable] of the current Working Draft (N2009)
+says:
+
    
+
    
+The Swappable requirement is met by satisfying one or more of the
+following conditions:
    
+
      
+
    • 
+T is Swappable if T satisfies the CopyConstructible requirements
+(20.1.3) and the Assignable requirements (23.1);
+
      • 
+
    • 
+T is Swappable if a namespace scope function named swap exists in the
+same namespace as the definition of T, such that the expression
+swap(t,u) is valid and has the semantics described in Table 33.
+
      • 
+
    
+
    
+I can think of three disadvantages of this definition:
+
      
+
    1. 
+If a client's type T satisfies the first condition (T is both
+CopyConstructible and Assignable), the client cannot stop T from
+satisfying the Swappable requirement without stopping T from
+satisfying the first condition.
+
      
+A client might want to stop T from satisfying the Swappable
+requirement, because swapping by means of copy construction and
+assignment might throw an exception, and she might find a throwing
+swap unacceptable for her type. On the other hand, she might not feel
+the need to fully implement her own swap function for this type. In
+this case she would want to be able to simply prevent algorithms that
+would swap objects of type T from being used, e.g., by declaring a
+swap function for T, and leaving this function purposely undefined.
+This would trigger a link error, if an attempt would be made to use
+such an algorithm for this type. For most standard library
+implementations, this practice would indeed have the effect of
+stopping T from satisfying the Swappable requirement.
+
      
+
      2. 
+
    2. 
+A client's type T that does not satisfy the first condition can not be
+made Swappable by providing a specialization of std::swap for T.
+
      
+While I'm aware about the fact that people have mixed feelings about
+providing a specialization of std::swap, it is well-defined to do so.
+It sounds rather counter-intuitive to say that T is not Swappable, if
+it has a valid and semantically correct specialization of std::swap.
+Also in practice, providing such a specialization will have the same
+effect as satisfying the Swappable requirement.
+
      
+
      3. 
+
    3. 
+For a client's type T that satisfies both conditions of the Swappable
+requirement, it is not specified which of the two conditions prevails.
+After reading section 20.1.4 [lib.swappable], one might wonder whether
+objects of T will be swapped by doing copy construction and
+assignments, or by calling the swap function of T.
+
      
+I'm aware that the intention of the Draft is to prefer calling the
+swap function of T over doing copy construction and assignments. Still
+in my opinion, it would be better to make this clear in the wording of
+the definition of Swappable. 
+
      
+
      4. 
+
    
+
    
+I would like to have the Swappable requirement defined in such a way
+that the following code fragment will correctly swap two objects of a
+type T, if and only if T is Swappable:
+
    
+
       using std::swap;
+   swap(t, u);  // t and u are of type T.
+
    
+
    
+This is also the way Scott Meyers recommends calling a swap function,
+in Effective C++, Third Edition, item 25.
+
    
+
    
+Most aspects of this issue have been dealt with in a discussion on
+comp.std.c++ about the Swappable requirement, from 13 September to 4
+October 2006, including valuable input by David Abrahams, Pete Becker,
+Greg Herlihy, Howard Hinnant and others.
 
    
 
+
    [
+San Francisco:
+]
    
 
 
+
    
+Recommend NAD.  Solved by
+N2774.
+
    
 
-
-
    
-
    564. stringbuf seekpos underspecified
    
-
    Section: 27.8.1.4 [stringbuf.virtuals] Status: Open
- Submitter: Martin Sebor Opened: 2006-02-23  Last modified: 2007-10-10
    
-
    View all other issues in [stringbuf.virtuals].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    
-The   effects  of  the   seekpos()  member   function  of
-basic_stringbuf  simply say  that the  function positions
-the  input and/or  output  sequences  but fail  to  spell out  exactly
-how. This is in contrast  to the detail in which seekoff()
-is described.
-
    
+
    [
+2009-07 Frankfurt
+]
    
 
 
-
    Proposed resolution:
    
-        
    
+
    
+Moved to Open.  Waiting for non-concepts draft.
+
    
 
-Change 27.7.1.3, p13 to read:
 
-        
    
-
    
+
    Proposed resolution:
    
 
    
--13- Effects: Same as seekoff(off_type(sp), ios_base::beg,
-which). Alters the stream position within the controlled sequences,
-if possible, to correspond to the stream position stored in sp
-(as described below).
+Change section 20.1.4 [lib.swappable] as follows:
 
    
+
    
+The Swappable requirement is met by satisfying
+one or more of the following conditions:
+the following condition:
    
 
      
-
    • If (which & ios_base::in) != 0, positions the input sequence.
      • 
-
    • If (which & ios_base::out) != 0, positions the output sequence.
      • 
-
    • If sp is an invalid stream position, or if the function
-positions neither sequence, the positioning operation fails. If sp
-has not been obtained by a previous successful call to one of the positioning
-functions (seekoff, seekpos, tellg, tellp)
-the effect is undefined.
      • 
+
+
    • 
+T is Swappable if T satisfies the CopyConstructible requirements
+(20.1.3) and the Assignable requirements (23.1);
+
      • 
+
    • 
+
+T is Swappable if a namespace scope function named swap exists in the
+same namespace as the definition of T, such that the expression
+swap(t,u) is valid and has the semantics described in Table 33.
+
+T is Swappable if an unqualified function call swap(t,u) is valid
+within the namespace std, and has the semantics described in Table 33.
+
      • 
 
    
 
    
 
 
-
    [
-Kona (2007): A pos_type is a position in a stream by
-definition, so there is no ambiguity as to what it means. Proposed
-Disposition: NAD
-]
    
-
-
-
    [
-Post-Kona Martin adds:
-I'm afraid I disagree
-with the Kona '07 rationale for marking it NAD. The only text
-that describes precisely what it means to position the input
-or output sequence is in seekoff(). The seekpos() Effects
-clause is inadequate in comparison and the proposed resolution
-plugs the hole by specifying seekpos() in terms of seekoff().
-]
    
-
-
 
 
 
 
    
-
    565. xsputn inefficient
    
-
    Section: 27.6.2.4.5 [streambuf.virt.put] Status: Open
- Submitter: Martin Sebor Opened: 2006-02-23  Last modified: 2007-10-09
    
-
    View all issues with Open status.
    
+
    617. std::array is a sequence that doesn't satisfy the sequence requirements?
    
+
    Section: 23.3.1 [array] Status: Tentatively NAD
+ Submitter: Bo Persson Opened: 2006-12-30  Last modified: 2009-07-16
    
+
    View other active issues in [array].
    
+
    View all other issues in [array].
    
+
    View all issues with Tentatively NAD status.
    
 
    Discussion:
    
-        
    
-
-streambuf::xsputn()  is  specified  to  have  the  effect  of
-"writing up to  n characters to the output  sequence as if by
-repeated calls to sputc(c)."
-
-        
    
-        
    
-
-Since  sputc() is required  to call  overflow() when
-(pptr()    ==   epptr())    is   true,    strictly   speaking
-xsputn()  should do  the same.   However, doing  so  would be
-suboptimal in  some interesting cases,  such as in unbuffered  mode or
-when the buffer is basic_stringbuf.
-
-        
    
-        
    
-
-Assuming  calling overflow()  is  not really  intended to  be
-required  and the  wording is  simply  meant to  describe the  general
-effect of appending to the end  of the sequence it would be worthwhile
-to  mention in  xsputn() that  the function  is  not actually
-required to cause a call to overflow().
-
-        
    
-
-
-
    Proposed resolution:
    
-        
    
-
-Add the following sentence  to the xsputn() Effects clause in
-27.5.2.4.5, p1 (N1804):
-
-        
    
-        
        
-            
    
--1- Effects: Writes up to n characters to the output
-sequence as if by repeated calls to sputc(c). The characters 
-written are obtained from successive elements of the array whose first element
-is designated by s. Writing stops when either n
-characters have been written or a call to sputc(c) would return
-traits::eof(). It is  uspecified whether the function  calls
-overflow() when (pptr() ==  epptr()) becomes true or whether
-it achieves the same effects by other means.
-            
    
-        
        
-        
    
+
    
+The <array> header is given under 23.3 [sequences].
+23.3.1 [array]/paragraph 3 says:
+
    
+
    
+"Unless otherwise specified, all array operations are as described in
+23.2 [container.requirements]".
+
    
+
    
+However, array isn't mentioned at all in section 23.2 [container.requirements].
+In particular, Table 82 "Sequence requirements" lists several operations (insert, erase, clear) 
+that std::array does not have in 23.3.1 [array].
+
    
+
    
+Also, Table 83 "Optional sequence operations" lists several operations that 
+std::array does have, but array isn't mentioned.
+
    
 
-In addition,  I suggest to  add a footnote  to this function  with the
-same text as Footnote 292 to  make it extra clear that derived classes
-are permitted to override xsputn() for efficiency.
+
    [
+2009-07 Frankfurt
+]
    
 
-        
    
 
+
    
+
    
+The real issue seems to be different than what is described here.
+Non-normative text says that std::array is a sequence container, but
+there is disagreement about what that really means. There are two
+possible interpretations:
+
    
+
      
+
    1. 
+a sequence container is one that satisfies all sequence container requirements
+
      2. 
+
    2. 
+a sequence container is one that satisfies some of the sequence
+container requirements. Any operation that the container supports is
+specified by one or more sequence container requirements, unless that
+operation is specifically singled out and defined alongside the
+description of the container itself.
+
      3. 
+
    
+
    
+Move to Tentatively NAD.
+
    
+
    
 
 
    [
-Kona (2007): We want to permit a streambuf that streams output directly
-to a device without making calls to sputc or overflow. We believe that
-has always been the intention of the committee. We believe that the
-proposed wording doesn't accomplish that. Proposed Disposition: Open
+2009-07-15 Loïc Joly adds:
 ]
    
 
 
+
    
+
    
+The section 23.2.3 [sequence.reqmts]/1 states that array is a sequence. 23.2.3 [sequence.reqmts]/3
+introduces table 83, named Sequence container requirements. This seems
+to me to be defining the requirements for all sequences. However, array
+does not follow all of this requirements (this can be read in the array
+specific section, for the standard is currently inconsistent).
+
    
 
-
-
-
    
-
    568. log2 overloads missing
    
-
    Section: TR1 8.16.4 [tr.c99.cmath.over] Status: Tentatively NAD
- Submitter: Paolo Carlini Opened: 2006-03-07  Last modified: 2009-05-23
    
-
    View all issues with Tentatively NAD status.
    
-
    Discussion:
    
 
    
-log2 is missing from the list of "additional overloads" in TR1 8.16.4 [tr.c99.cmath.over] p1.
+Proposed resolution 1 (minimal change): 
+
    
+
    
+
    
+Say that array is a container, that in addition follows only some of the
+sequence requirements, as described in the array section:
 
    
 
+
    
+The library provides five three basic kinds of sequence containers: array,
+vector, 
+forward_list, list, and deque. In addition, array
+and forward_list follows some of the requirements 
+of sequences, as described in their respective sections.
+
    
+
+
    
+
 
    
-Hinnant:  This is a TR1 issue only.  It is fixed in the current (N2135) WD.
+Proposed resolution 2 (most descriptive description, no full wording provided): 
 
    
+
    
+Introduce the notion of a Fixed Size Sequence, with it requirement table
+that would be a subset of the current Sequence container. array would be
+the only Fixed Size Sequence (but dynarray is in the queue for TR2).
+Sequence requirements would now be requirements in addition to Fixed
+Size Sequence requirements (it is currently in addition to container).
+
    
+
    
 
 
    [
-Batavia (2009-05):
+2009-07 Frankfurt:
 ]
    
 
+
 
    
-We agree this has been fixed in the Working Draft.
-Move to NAD.
+Move to NAD Editorial
 
    
 
 
+
 
    Proposed resolution:
    
 
    
-Add log2 to the list of functions in TR1 8.16.4 [tr.c99.cmath.over] p1.
 
    
 
 
@@ -6028,855 +5029,515 @@ Add log2 to the list of functions in TR1 8.16.4 [tr.c99.cmath.over] p1.
 
 
 
    
-
    573. C++0x file positioning should handle modern file sizes
    
-
    Section: 27.5.3 [fpos] Status: Open
- Submitter: Beman Dawes Opened: 2006-04-12  Last modified: 2007-10-09
    
-
    View all other issues in [fpos].
    
-
    View all issues with Open status.
    
+
    625. mixed up Effects and Returns clauses
    
+
    Section: 17 [library] Status: Tentatively NAD
+ Submitter: Martin Sebor Opened: 2007-01-20  Last modified: 2009-07-15
    
+
    View other active issues in [library].
    
+
    View all other issues in [library].
    
+
    View all issues with Tentatively NAD status.
    
+
    Duplicate of: 895
    
 
    Discussion:
    
-
    
-There are two deficiencies related to file sizes:
+ 
    
+
+Many member functions of basic_string are overloaded,
+with some of the overloads taking a string argument,
+others value_type*, others size_type, and
+others still iterators. Often, the requirements on one of
+the overloads are expressed in the form of Effects,
+Throws, and in the Working Paper
+(N2134)
+also Remark clauses, while those on the rest of the overloads
+via a reference to this overload and using a Returns clause.
 
    
-
      
-
    1. It doesn't appear that the Standard Library is specified in
-      a way that handles modern file sizes, which are often too
-      large to be represented by an unsigned long.
      2. 
 
-
    2. The std::fpos class does not currently have the ability to
-      set/get file positions.
      3. 
-
    
 
    
-The Dinkumware implementation of the Standard Library as shipped with the Microsoft compiler copes with these issues by:
+The difference between the two forms of specification is that per
+17.5.1.4 [structure.specifications], p3, an Effects clause specifies
+"actions performed by the functions," i.e., its observable
+effects, while a Returns clause is "a description of the
+return value(s) of a function" that does not impose any
+requirements on the function's observable effects.
 
    
-
      
-
    1. Defining fpos_t be long long, which is large enough to
-      represent any file position likely in the foreseeable future.
      2. 
 
-
    2. Adding member functions to class fpos. For example,
-
      fpos_t seekpos() const;
-
      
-
      3. 
-
    
 
    
-Because there are so many types relating to file positions and offsets (fpos_t,
-fpos, pos_type, off_type, streamoff, streamsize, streampos, wstreampos, and
-perhaps more), it is difficult to know if the Dinkumware extensions are
-sufficient. But they seem a useful starting place for discussions, and they do
-represent existing practice.
+Since only Notes are explicitly defined to be informative and
+all other paragraphs are explicitly defined to be normative, like
+Effects and Returns, the new Remark clauses also
+impose normative requirements.
 
    
 
-
    [
-Kona (2007): We need a paper. It would be nice if someone proposed
-clarifications to the definitions of pos_type and off_type. Currently
-these definitions are horrible. Proposed Disposition: Open
-]
    
-
-
-
-
    Proposed resolution:
    
 
    
+So by this strict reading of the standard there are some member
+functions of basic_string that are required to throw an
+exception under some conditions or use specific traits members while
+many other otherwise equivalent overloads, while obliged to return the
+same values, aren't required to follow the exact same requirements
+with regards to the observable effects.
 
    
 
+
    
+Here's an example of this problem that was precipitated by the change
+from informative Notes to normative Remarks (presumably made to
+address 424):
+
    
 
+
    
+In the Working Paper, find(string, size_type) contains a
+Remark clause (which is just a Note in the current
+standard) requiring it to use traits::eq().
+
    
 
+
    
+find(const charT *s, size_type pos) is specified to
+return find(string(s), pos) by a Returns clause
+and so it is not required to use traits::eq(). However,
+the Working Paper has replaced the original informative Note
+about the function using traits::length() with a
+normative requirement in the form of a Remark. Calling
+traits::length() may be suboptimal, for example when the
+argument is a very long array whose initial substring doesn't appear
+anywhere in *this.
+
    
 
+
    
+Here's another similar example, one that existed even prior to the
+introduction of Remarks:
+
    
 
-
    
-
    580. unused allocator members
    
-
    Section: 23.2.1 [container.requirements.general] Status: Open
- Submitter: Martin Sebor Opened: 2006-06-14  Last modified: 2009-05-01
    
-
    View other active issues in [container.requirements.general].
    
-
    View all other issues in [container.requirements.general].
    
-
    View all issues with Open status.
    
-
    Duplicate of: 479
    
-
    Discussion:
    
-        
    
+
    
+ insert(size_type pos, string, size_type, size_type) is
+required to throw out_of_range if pos >
+size().
+
    
 
-C++ Standard Library  templates that take an allocator  as an argument
-are    required    to    call    the    allocate()    and
-deallocate()  members of the  allocator object  to obtain
-storage.  However, they do not appear to be required to call any other
-allocator      members      such     as      construct(),
-destroy(),           address(),          and
-max_size().  This makes these allocator members less than
-useful in portable programs.
+
    
+insert(size_type pos, string str) is specified to return
+insert(pos, str, 0, npos) by a Returns clause and
+so its effects when pos > size() are strictly speaking
+unspecified.
+
    
 
-        
    
-        
    
+
    
+I believe a careful review of the current Effects and
+Returns clauses is needed in order to identify all such
+problematic cases. In addition, a review of the Working Paper should
+be done to make sure that the newly introduced normative Remark
+clauses do not impose any undesirable normative requirements in place
+of the original informative Notes.
 
-It's unclear to me whether the absence of the requirement to use these
-allocator  members  is  an  unintentional  omission  or  a  deliberate
-choice. However,  since the functions exist in  the standard allocator
-and  since  they are  required  to  be  provided by  any  user-defined
-allocator I  believe the standard  ought to be clarified  to explictly
-specify  whether programs  should or  should not  be able  to  rely on
-standard containers calling the functions.
 
-        
    
-        
    
+
    [
+Batavia: Alan and Pete to work.
+]
    
 
-I  propose  that all  containers  be required  to  make  use of  these
-functions.
 
-        
    
 
    [
-Batavia:  We support this resolution.  Martin to provide wording.
+Bellevue: Marked as NAD Editorial.
 ]
    
 
+
 
    [
-pre-Oxford:  Martin provided wording.
+Post-Sophia Antipolis:
+Martin indicates there is still work to be done on this issue.
+Reopened.
 ]
    
 
 
 
    [
-2009-04-28 Pablo adds:
+Batavia (2009-05):
 ]
    
 
-
 
    
-N2554
-(scoped allocators),
-N2768
-(allocator concepts), and
-N2810
-(allocator defects), address all of these points EXCEPT max_size().
-So, I would add a note to that affect and re-class the defect as belonging
-to section 23.2.1 [container.requirements.general].
+Tom proposes we say that, unless specified otherwise,
+it is always the caller's responsibility to verify that supplied arguments
+meet the called function's requirements.
+If further semantics are specified
+(e.g., that the function throws under certain conditions),
+then it is up to the implementer to check those conditions.
+Alan feels strongly that our current use of Requires in this context
+is confusing, especially now that requires is a new keyword.
 
    
 
-    
-
-    
    Proposed resolution:
    
-       
    
-
-Specifically, I propose to change 23.2 [container.requirements],
-p9 as follows:
-
-       
    
-           
    
-
    
--9- Copy constructors  for all container types defined  in this clause
-that   are  parametrized  on   Allocator  copy
-anthe  allocator argument from  their respective
-first parameters.
+
    [
+2009-07 Frankfurt
+]
    
 
-All other  constructors for  these container types  take an
-const  Allocator&  argument  (20.1.6),  an
-allocator whose value_type is the same as the container's
-value_type.
 
-A copy of this  argument isshall be used for any
-memory  allocation  and  deallocation performed,
-by these  constructors and by all  member functions, during
-the  lifetime  of each  container  object.   Allocation shall  be
-performed  "as  if"  by  calling  the  allocate()  member
-function on  a copy  of the allocator  object of the  appropriate type
-New  Footnote),   and  deallocation  "as   if"  by  calling
-deallocate() on  a copy of  the same allocator  object of
-the corresponding type.
+
    
+Move to Tentatively NAD.
+
    
 
-A  copy of  this argument  shall also  be used  to  construct and
-destroy objects whose lifetime  is managed by the container, including
-but not  limited to those of  the container's value_type,
-and  to  obtain  their  address.   All  objects  residing  in  storage
-allocated by a  container's allocator shall be constructed  "as if" by
-calling the construct() member  function on a copy of the
-allocator object of  the appropriate type.  The same  objects shall be
-destroyed "as if"  by calling destroy() on a  copy of the
-same allocator object  of the same type.  The  address of such objects
-shall be obtained "as if" by calling the address() member
-function  on  a  copy  of  the allocator  object  of  the  appropriate
-type.
 
-Finally, a copy  of this argument shall be  used by its container
-object to determine  the maximum number of objects  of the container's
-value_type the container may  store at the same time. The
-container  member function max_size() obtains  this number
-from      the      value      returned      by     a      call      to
-get_allocator().max_size().
 
-In   all  container   types  defined   in  this   clause that  are
-parametrized     on    Allocator,     the    member
-get_allocator()     returns     a     copy     of     the
-Allocator     object     used     to    construct     the
-container.258)
-
    
+
    Proposed resolution:
    
 
    
-New Footnote: This type  may be different from Allocator:
-it     may    be     derived    from     Allocator    via
-Allocator::rebind<U>::other   for  the  appropriate
-type U.
 
    
-           
    
-       
    
-
-The proposed wording seems cumbersome but I couldn't think of a better
-way   to  describe   the   requirement  that   containers  use   their
-Allocator  to manage  only objects  (regardless  of their
-type)  that  persist  over  their  lifetimes  and  not,  for  example,
-temporaries  created on the  stack. That  is, containers  shouldn't be
-required  to  call  Allocator::construct(Allocator::allocate(1),
-elem)  just to  construct a  temporary copy  of an  element, or
-Allocator::destroy(Allocator::address(temp),     1)    to
-destroy temporaries.
-
-       
    
-
-
-
    [
-Howard: This same paragraph will need some work to accommodate 431.
-]
    
-
-
-
    [
-post Oxford:  This would be rendered NAD Editorial by acceptance of
-N2257.
-]
    
 
 
 
 
 
 
    
-
    582. specialized algorithms and volatile storage
    
-
    Section: 20.8.11.2 [uninitialized.copy] Status: Open
- Submitter: Martin Sebor Opened: 2006-06-14  Last modified: 2009-03-14
    
-
    View all other issues in [uninitialized.copy].
    
-
    View all issues with Open status.
    
+
    630. arrays of valarray
    
+
    Section: 26.6.2.1 [valarray.cons] Status: Ready
+ Submitter: Martin Sebor Opened: 2007-01-28  Last modified: 2009-07-15
    
+
    View all other issues in [valarray.cons].
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
-
-
    Related to 1029
    
         
    
 
-The specialized  algorithms [lib.specialized.algorithms] are specified
-as having the general effect of invoking the following expression:
+Section 26.2 [numeric.requirements], p1     suggests     that     a
+valarray  specialization on  a  type T  that
+satisfies  the requirements enumerated  in the  paragraph is  itself a
+valid  type   on  which  valarray   may  be  instantiated
+(Footnote       269        makes       this       clear).        I.e.,
+valarray<valarray<T>  > is  valid as  long as
+T   is   valid.    However,  since   implementations   of
+valarray are permitted to initialize storage allocated by
+the class by  invoking the default ctor of  T followed by
+the    copy    assignment    operator,   such    implementations    of
+valarray   wouldn't  work  with   (perhaps  user-defined)
+specializations of valarray whose assignment operator had
+undefined behavior when the size of its argument didn't match the size
+of *this.  By "wouldn't work" I mean that it would
+be  impossible  to resize  such  an array  of  arrays  by calling  the
+resize() member  function on it if the  function used the
+copy  assignment operator  after constructing  all elements  using the
+default  ctor (e.g.,  by invoking  new  value_type[N]) to
+obtain default-initialized storage) as it's permitted to do.
 
         
    
-            
    -new (static_cast<void*>(&*i))
-    typename iterator_traits<ForwardIterator>::value_type (x)
-
-            
    
         
    
 
-This  expression is  ill-formed  when the  type  of the  subexpression
-&*i is some volatile-qualified T.
+Stated      more     generally,      the      problem     is      that
+valarray<valarray<T>  >::resize(size_t) isn't
+required or  guaranteed to have well-defined semantics  for every type
+T     that      satisfies     all     requirements     in
+26.2 [numeric.requirements].
 
         
    
-
-
    [
-Batavia:  Lack of support for proposed resolution but agree there is a
-defect.  Howard to look at wording.  Concern that move semantics
-properly expressed if iterator returns rvalue.
-]
    
-
-
-    
-
-    
    Proposed resolution:
    
         
    
 
-In order  to allow these algorithms  to operate on  volatile storage I
-propose to change the expression so as to make it well-formed even for
-pointers  to volatile  types.  Specifically,  I propose  the following
-changes to clauses 20 and 24. Change 20.6.4.1, p1 to read:
+I  believe  this  problem  was  introduced  by  the  adoption  of  the
+resolution                outlined                in                N0857,
+Assignment  of  valarrays,  from  1996.   The  copy  assignment
+operator  of  the original  numerical  array  classes  proposed in  N0280,
+as      well       as      the      one       proposed      in      N0308
+(both  from 1993), had  well-defined semantics  for arrays  of unequal
+size (the  latter explicitly  only when *this  was empty;
+assignment of non empty arrays of unequal size was a runtime error).
 
         
    
-            
    -Effects:
-
-typedef typename iterator_traits<ForwardIterator>::pointer    pointer;
-typedef typename iterator_traits<ForwardIterator>::value_type value_type;
-
-for (; first != last; ++result, ++first)
-    new (static_cast<void*>(const_cast<pointer>(&*result))
-        value_type (*first);
-
-            
    
         
    
 
-change 20.6.4.2, p1 to read
+The  justification for  the  change given  in  N0857 was the "loss  of
+performance [deemed]  only significant  for very simple  operations on
+small arrays or for architectures with very few registers."
 
         
    
-            
    -Effects:
-
-typedef typename iterator_traits<ForwardIterator>::pointer    pointer;
-typedef typename iterator_traits<ForwardIterator>::value_type value_type;
-
-for (; first != last; ++result, ++first)
-    new (static_cast<void*>(const_cast<pointer>(&*first))
-        value_type (*x);
-
-            
    
         
    
 
-and change 20.6.4.3, p1 to read
+Since tiny  arrays on a  limited subset of hardware  architectures are
+likely  to  be  an   exceedingly  rare  case  (despite  the  continued
+popularity of  x86) I  propose to revert  the resolution and  make the
+behavior    of   all   valarray    assignment   operators
+well-defined even  for non-conformal  arrays (i.e., arrays  of unequal
+size).   I have implemented  this change  and measured  no significant
+degradation  in performance in  the common  case (non-empty  arrays of
+equal size).  I  have measured a 50% (and in  some cases even greater)
+speedup  in the  case of  assignments to  empty arrays  versus calling
+resize()  first followed  by  an invocation  of the  copy
+assignment operator.
 
         
    
-            
    -Effects:
 
-typedef typename iterator_traits<ForwardIterator>::pointer    pointer;
-typedef typename iterator_traits<ForwardIterator>::value_type value_type;
+
    [
+Bellevue:
+]
    
 
-for (; n--; ++first)
-    new (static_cast<void*>(const_cast<pointer>(&*first))
-        value_type (*x);
 
-            
    
-        
    
+
    
+If no proposed wording by June meeting, this issue should be closed NAD.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
 
-In   addition,  since   there   is  no   partial  specialization   for
-iterator_traits<volatile T*>  I propose to  add one
-to parallel such specialization  for <const T*>. Specifically, I
-propose to add the following text to the end of 24.3.1, p3:
 
-        
    
-        
    
+
    
+
    
+Move resolution 1 to Ready.
+
    
+
    
+Howard: second resolution has been commented out (made invisible).
+Can be brought back on demand.
+
    
+
    
 
-and for pointers to volatile as 
 
-        
    
-            
    -namespace std {
-template<class T> struct iterator_traits<volatile T*> {
-typedef ptrdiff_t difference_type;
-typedef T value_type;
-typedef volatile T* pointer;
-typedef volatile T& reference;
-typedef random_access_iterator_tag iterator_category;
-};
-}
 
-            
    
+
    Proposed resolution:
    
         
    
 
-Note that  the change to  iterator_traits isn't necessary
-in order to implement the  specialized algorithms in a way that allows
-them to operate on volatile  strorage. It is only necesassary in order
-to specify  their effects in terms  of iterator_traits as
-is  done here.   Implementations can  (and some  do) achieve  the same
-effect by means of function template overloading.
+Change 26.6.2.2 [valarray.assign], p1 as follows:
 
         
    
-    
-
+        
    
+            
    
+                
 
+valarray<T>& operator=(const valarray<T>& x);
 
-
    
-
    585. facet error reporting
    
-
    Section: 22.4 [locale.categories] Status: Open
- Submitter: Martin Sebor, Paolo Carlini Opened: 2006-06-22  Last modified: 2007-10-09
    
-
    View other active issues in [locale.categories].
    
-
    View all other issues in [locale.categories].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-        
    
+                
+            
    
+            
    
 
-Section  22.2, paragraph 2  requires facet  get() members
-that    take    an    ios_base::iostate&    argument,
-err,  to   ignore  the  (initial)   value  of  the
-argument, but to set it to ios_base::failbit in case of a
-parse error.
+-1- Each element of the *this array is assigned the value
+of  the  corresponding  element   of  the  argument  array.   The
+resulting behavior is undefined if When the length of
+the  argument  array  is  not   equal  to  the  length  of  the  *this
+array.  resizes  *this  to make  the  two
+arrays     the      same     length,     as      if     by     calling
+resize(x.size()), before performing the assignment.
 
-        
    
+            
    
+        
    
         
    
 
-We  believe  there  are  a   few  minor  problems  with  this  blanket
-requirement  in   conjunction  with   the  wording  specific   to  each
-get() member function.
+And  add a new  paragraph just  below paragraph  1 with  the following
+text:
 
         
    
-        
    
+        
    
+            
    
 
-First,  besides get()  there are  other  member functions
-with     a      slightly     different     name      (for     example,
-get_date()). It's not completely clear that the intent of
-the  paragraph  is  to  include  those  as  well,  and  at  least  one
-implementation has interpreted the requirement literally.
+-2- Postcondition: size() == x.size().
 
-        
    
+            
    
+        
    
         
    
 
-Second,    the     requirement    to    "set     the    argument    to
-ios_base::failbit  suggests that  the  functions are  not
-permitted    to   set    it   to    any   other    value    (such   as
-ios_base::eofbit,   or   even  ios_base::eofbit   |
-ios_base::failbit).
+Also add the following paragraph to 26.6.2.2 [valarray.assign], immediately after p4:
 
         
    
-        
    
-
-However, 22.2.2.1.2, p5 (Stage  3 of num_get parsing) and
-p6 (bool parsing)  specifies that the do_get
-functions  perform err |=  ios_base::eofbit, which
-contradicts  the earlier  requirement to  ignore  err's initial
-value.
+        
    
+            
    
 
-        
    
-        
    
+-?- When the length,  N of the array referred
+to by the  argument is not equal to  the length of *this,
+the  operator resizes *this  to make  the two  arrays the
+same  length, as if  by calling  resize(N), before
+performing the assignment.
 
-22.2.6.1.2,  p1  (the  Effects  clause of  the  money_get
-facet's  do_get  member  functions) also  specifies  that
-err's initial  value be used to  compute the final
-value  by  ORing  it  with  either  ios_base::failbit  or
-withios_base::eofbit | ios_base::failbit.
+            
    
+        
    
 
-        
    
-    
+
    [
+pre-Sophia Antipolis, Martin adds the following compromise wording, but
+prefers the original proposed resolution:
+]
    
 
-    
    Proposed resolution:
    
-        
    
 
-We believe the  intent is for all facet member  functions that take an
-ios_base::iostate& argument to:
 
-        
    
-            
      
-                
    • 
 
-ignore the initial value of the err argument,
 
-                
      • 
-                
    • 
 
-reset err  to ios_base::goodbit prior
-to any further processing,
+
      [
+Kona (2007): Gaby to propose wording for an alternative resolution in
+which you can assign to a valarray of size 0, but not to any other
+valarray whose size is unequal to the right hand side of the assignment.
+]
      
 
-                
      • 
-                
    • 
-
-and       set      either       ios_base::eofbit,      or
-ios_base::failbit, or both in err, as
-appropriate,  in response  to  reaching the  end-of-file  or on  parse
-error, or both.
-
-                
      • 
-            
    
-        
    
-
-To that effect we propose to change 22.2, p2 as follows:
-
-        
    
-        
    
-
-The  put()  members  make  no  provision  for  error
-reporting.   (Any  failures of  the  OutputIterator  argument must  be
-extracted   from  the   returned  iterator.)    Unless  otherwise
-specified, the get()  members  that
-take an  ios_base::iostate& argument whose value
-they  ignore,  but  set  to  ios_base::failbit  in  case  of  a  parse
-error.,   err,   start  by   evaluating
-err  =   ios_base::goodbit,  and  may   subsequently  set
-err     to     either     ios_base::eofbit,     or
-ios_base::failbit,     or     ios_base::eofbit    |
-ios_base::failbit in response to reaching the end-of-file or in
-case of a parse error, or both, respectively.
-
-        
    
-    
-    
-
    [
-Kona (2007): We need to change the proposed wording to clarify that the
-phrase "the get members" actually denotes get(), get_date(), etc.
-Proposed Disposition: Open
-]
    
 
 
 
 
 
    
-
    588. requirements on zero sized tr1::arrays and other details
    
-
    Section: 23.3.1 [array] Status: Open
- Submitter: Gennaro Prota Opened: 2006-07-18  Last modified: 2009-05-30
    
-
    View other active issues in [array].
    
-
    View all other issues in [array].
    
+
    631. conflicting requirements for BinaryPredicate
    
+
    Section: 25 [algorithms] Status: Open
+ Submitter: James Kanze Opened: 2007-01-31  Last modified: 2009-07-28
    
+
    View other active issues in [algorithms].
    
+
    View all other issues in [algorithms].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-The wording used for section 23.2.1 [lib.array] seems to be subtly
-ambiguous about zero sized arrays (N==0). Specifically:
-
    
-
    
-* "An instance of array<T, N> stores N elements of type T, so that
-[...]"
-
    
-
    
-Does this imply that a zero sized array object stores 0 elements, i.e.
-that it cannot store any element of type T? The next point clarifies
-the rationale behind this question, basically how to implement begin()
-and end():
-
    
-
    
-* 23.2.1.5 [lib.array.zero], p2: "In the case that N == 0, begin() ==
-end() == unique value."
-
    
-
    
-What does "unique" mean in this context? Let's consider the following
-possible implementations, all relying on a partial specialization:
+The general requirements for BinaryPredicate (in 25 [algorithms]/8) contradict the implied specific requirements for
+some functions. In particular, it says that:
 
    
-
    a)
-    template< typename T >
-    class array< T, 0 > {
-    
-        ....
 
-        iterator begin()
-        { return iterator( reinterpret_cast< T * >( this ) ); }
-        ....
+
    
+[...] if an algorithm takes BinaryPredicate binary_pred
+as its argument and first1 and first2 as its
+iterator arguments, it should work correctly in the construct if
+(binary_pred (*first1 , *first2 )){...}.
+BinaryPredicate always takes the first iterator type as its
+first argument, that is, in those cases when T value is
+part of the signature, it should work correctly in the context of if
+(binary_pred (*first1 , value)){...}.
+
    
 
-    };
-
    
 
    
-This has been used in boost, probably intending that the return value
-had to be unique to the specific array object and that array couldn't
-store any T. Note that, besides relying on a reinterpret_cast, has
-(more than potential) alignment problems.
+In the description of upper_bound (25.5.3.2 [upper.bound]/2), however, the use is described as
+"!comp(value, e)", where e is an
+element of the sequence (a result of dereferencing
+*first).
 
    
-
    b)
-    template< typename T >
-    class array< T, 0 > {
-    
-        T t;
-
-        iterator begin()
-        { return iterator( &t ); }
-        ....
 
-    };
-
    
-
    
-This provides a value which is unique to the object and to the type of
-the array, but requires storing a T. Also, it would allow the user to
-mistakenly provide an initializer list with one element.
-
    
-
    
-A slight variant could be returning *the* null pointer of type T
-
    
-
        return static_cast<T*>(0);
-
    
-
    
-In this case the value would be unique to the type array<T, 0> but not
-to the objects (all objects of type array<T, 0> with the same value
-for T would yield the same pointer value).
-
    
-
    
-Furthermore this is inconsistent with what the standard requires from
-allocation functions (see library issue 9).
-
    
-
    
-c) same as above but with t being a static data member; again, the
-value would be unique to the type, not to the object.
-
    
-
    
-d) to avoid storing a T *directly* while disallowing the possibility
-to use a one-element initializer list a non-aggregate nested class
-could be defined
-
    
-
        struct holder { holder() {} T t; } h;
-
    
-
    
-and then begin be defined as
-
    
-
     iterator begin() { return &h.t; }
-
    
-
    
-But then, it's arguable whether the array stores a T or not.
-Indirectly it does.
-
    
-
    
------------------------------------------------------
-
    
-
    
-Now, on different issues:
-
    
-
    
-* what's the effect of calling assign(T&) on a zero-sized array? There
-seems to be only mention of front() and back(), in 23.2.1 [lib.array]
-p4 (I would also suggest to move that bullet to section 23.2.1.5
-[lib.array.zero], for locality of reference)
-
    
-
    
-* (minor) the opening paragraph of 23.2.1 [lib.array] wording is a bit
-inconsistent with that of other sequences: that's not a problem in
-itself, but compare it for instance with "A vector is a kind of
-sequence that supports random access iterators"; though the intent is
-obvious one might argue that the wording used for arrays doesn't tell
-what an array is, and relies on the reader to infer that it is what
-the <array> header defines.
-
    
-
    
-* it would be desiderable to have a static const data member of type
-std::size_t, with value N, for usage as integral constant expression
-
    
-
    
-* section 23.1 [lib.container.requirements] seem not to consider
-fixed-size containers at all, as it says: "[containers] control
-allocation and deallocation of these objects [the contained objects]
-through constructors, destructors, *insert and erase* operations"
-
    
 
    
-* max_size() isn't specified: the result is obvious but, technically,
-it relies on table 80: "size() of the largest possible container"
-which, again, doesn't seem to consider fixed size containers
+In the description of lexicographical_compare, we have both
+"*first1 < *first2" and "*first2
+< *first1" (which presumably implies "comp(
+*first1, *first2 )" and "comp( *first2,
+*first1 )".
 
    
 
 
    [
-2009-05-29 Daniel adds:
+Toronto:  Moved to Open.  ConceptGCC seems to get lower_bound
+and upper_bound to work withoutt these changes.
 ]
    
 
 
-
    
-
      
-
    1. 
-
      
-star bullet 1 ("what's the effect of calling assign(T&) on a
-zero-sized array?[..]");
-
      
-
      
-assign has been renamed to fill and the semantic of fill is now
-defined in terms of
-the free algorithm fill_n, which is well-defined for this situation.
-
      
-
      2. 
-
    2. 
-
      
-star bullet 3 ("it would be desiderable to have a static const data
-member..."):
-
      
-
      
-It seems that tuple_size<array<T, N> >::value as of 23.3.1.7 [array.tuple] does
-provide this functionality now.
-
      
-
      3. 
-
    
-
    
-
-
-
    Proposed resolution:
    
-
    
-
    
-
-
 
    [
-Kona (2007): requirements on zero sized tr1::arrays and other details
-Issue 617: std::array is a sequence that doesn't satisfy the sequence
-requirements? Alisdair will prepare a paper. Proposed Disposition: Open
+2009-07-28 Reopened by Alisdair.  No longer solved by concepts.
 ]
    
 
 
 
 
-
-
    
-
    597. Decimal: The notion of 'promotion' cannot be emulated by user-defined types.
    
-
    Section: TRDecimal 3.2 [trdec.types.types] Status: Open
- Submitter: Daveed Vandevoorde Opened: 2006-04-05  Last modified: 2009-05-01
    
-
    View other active issues in [trdec.types.types].
    
-
    View all other issues in [trdec.types.types].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    
-In a private email, Daveed writes:
-
    
-
    
+
    Proposed resolution:
    
 
    
-I am not familiar with the C TR, but my guess is that the
-class type approach still won't match a built-in type
-approach because the notion of "promotion" cannot be
-emulated by user-defined types.
+Logically, the BinaryPredicate is used as an ordering
+relationship, with the semantics of "less than".  Depending on the
+function, it may be used to determine equality, or any of the inequality
+relationships; doing this requires being able to use it with either
+parameter first.  I would thus suggest that the requirement be:
 
    
+
+
    
+[...] BinaryPredicate always takes the first iterator
+value_type as one of its arguments, it is unspecified which. If
+an algorithm takes BinaryPredicate binary_pred as its
+argument and first1 and first2 as its
+iterator arguments, it should work correctly both in the construct
+if (binary_pred (*first1 , *first2 )){...} and
+if (binary_pred (*first2, *first1)){...}.  In
+those cases when T value is part of the signature, it
+should work correctly in the context of if (binary_pred
+(*first1 , value)){...} and of if (binary_pred
+(value, *first1)){...}. [Note: if the two
+types are not identical, and neither is convertable to the other, this
+may require that the BinaryPredicate be a functional object
+with two overloaded operator()() functions. --end note]
+
    
+
 
    
-Here is an example:
+Alternatively, one could specify an order for each function. IMHO, this
+would be more work for the committee, more work for the implementors,
+and of no real advantage for the user: some functions, such as
+lexicographical_compare or equal_range, will still require both
+functions, and it seems like a much easier rule to teach that both
+functions are always required, rather than to have a complicated list of
+when you only need one, and which one.
 
    
-
    
-
    -         struct S {
-           S(_Decimal32 const&);  // Converting constructor
-         };
-         void f(S);
 
-         void f(_Decimal64);
 
-         void g(_Decimal32 d) {
-           f(d);
-         }
-
    
+
    Rationale:
    
+
    [
+post San Francisco:
+]
    
+
 
 
    
-
    
-If _Decimal32 is a built-in type, the call f(d) will likely
-resolve to f(_Decimal64) because that requires only a
-promotion, whereas f(S) requires a user-defined conversion.
-
    
-
    
-If _Decimal32 is a class type, I think the call f(d) will be
-ambiguous because both the conversion to _Decimal64 and the
-conversion to S will be user-defined conversions with neither
-better than the other.
-
    
+Solved by
+N2759.
 
    
-
    
-Robert comments:
-
    
-
    
-In general, a library of arithmetic types cannot exactly emulate the
-behavior of the intrinsic numeric types. There are several ways to tell
-whether an implementation of the decimal types uses compiler
-intrinisics or a library. For example:
-
    
-
                     _Decimal32 d1;
-                 d1.operator+=(5);  // If d1 is a builtin type, this won't compile.
-
    
-
    
-In preparing the decimal TR, we have three options:
-
    
-
      
-
    1. require that the decimal types be class types
      2. 
-
    2. require that the decimal types be builtin types, like float and double
      3. 
-
    3. specify a library of class types, but allow enough implementor
-latitude that a conforming implementation could instead provide builtin
-types
      4. 
-
    
-
    
-We decided as a group to pursue option #3, but that approach implies
-that implementations may not agree on the semantics of certain use
-cases (first example, above), or on whether certain other cases are
-well-formed (second example). Another potentially important problem is
-that, under the present definition of POD, the decimal classes are not
-POD types, but builtins will be.
-
    
-
    Note that neither example above implies any problems with respect to
-C-to-C++ compatibility, since neither example can be expressed in C.
-
    
-
 
-
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    606. Decimal: allow narrowing conversions
    
-
    Section: TRDecimal 3.2 [trdec.types.types] Status: Open
- Submitter: Martin Sebor Opened: 2006-06-15  Last modified: 2007-01-15
    
-
    View other active issues in [trdec.types.types].
    
-
    View all other issues in [trdec.types.types].
    
+
    635. domain of allocator::address
    
+
    Section: X [allocator.requirements] Status: Open
+ Submitter: Howard Hinnant Opened: 2007-02-08  Last modified: 2009-07-28
    
+
    View other active issues in [allocator.requirements].
    
+
    View all other issues in [allocator.requirements].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-In c++std-lib-17205, Martin writes:
+The table of allocator requirements in X [allocator.requirements] describes
+allocator::address as:
 
    
-
    ...was it a deliberate design choice to make narrowing
-assignments ill-formed while permitting narrowing compound assignments?
-For instance:
-
    
-
          decimal32 d32;
-      decimal64 d64;
-
-      d32 = 64;     // error
-      d32 += 64;    // okay
-
    
+
    a.address(r)
+a.address(s)
+
    
 
    
-In c++std-lib-17229, Robert responds:
+where r and s are described as:
 
    
-
    It is a vestige of an old idea that I forgot to remove
-from the paper. Narrowing assignments should be permitted. The bug is
-that the converting constructors that cause narrowing should not be
-explicit. Thanks for pointing this out.
+
    
+a value of type X::reference obtained by the expression *p. 
 
    
 
-
    Proposed resolution:
    
 
    
-1.  In "3.2.2 Class decimal32" synopsis, remove the explicit specifier from the narrowing conversions:
+and p is 
 
    
-
                    // 3.2.2.2 conversion from floating-point type:
-                explicit decimal32(decimal64 d64);
-                explicit decimal32(decimal128 d128);
-
    
+
+
    
+a value of type X::pointer, obtained by calling a1.allocate, 
+where a1 == a
+
    
+
 
    
-2.  Do the same thing in "3.2.2.2. Conversion from floating-point type."
+This all implies that to get the address of some value of type T that
+value must have been allocated by this allocator or a copy of it.
 
    
+
 
    
-3.  In "3.2.3 Class decimal64" synopsis, remove the explicit specifier from the narrowing conversion:
+However sometimes container code needs to compare the address of an external value of
+type T with an internal value.  For example list::remove(const T& t)
+may want to compare the address of the external value t with that of a value
+stored within the list.  Similarly vector or deque insert may
+want to make similar comparisons (to check for self-referencing calls).
 
    
-
                    // 3.2.3.2 conversion from floating-point type:
-                explicit decimal64(decimal128 d128);
-
    
+
 
    
-4.  Do the same thing in "3.2.3.2. Conversion from floating-point type."
+Mandating that allocator::address can only be called for values which the
+allocator allocated seems overly restrictive.
 
    
 
 
    [
-Redmond: We prefer explicit conversions for narrowing and implicit for widening.
+post San Francisco:
 ]
    
 
 
+
    
+Pablo recommends NAD Editorial, solved by
+N2768.
+
    
 
-
-
-
-
    
-
    614. std::string allocator requirements still inconsistent
    
-
    Section: 21.4 [basic.string] Status: Open
- Submitter: Bo Persson Opened: 2006-12-05  Last modified: 2008-03-12
    
-
    View other active issues in [basic.string].
    
-
    View all other issues in [basic.string].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    
-This is based on N2134, where 21.3.1/2 states:
-"... The Allocator object used shall be a copy of the Allocator object 
-passed to the basic_string object's constructor or, if the constructor does 
-not take an Allocator argument, a copy of a default-constructed Allocator 
-object."
-
    
-
    
-Section 21.3.2/1 lists two constructors:
-
    
-
    basic_string(const basic_string<charT,traits,Allocator>& str );
-
-basic_string(const basic_string<charT,traits,Allocator>& str ,
-             size_type pos , size_type n = npos,
-             const Allocator& a = Allocator());
-
    
-
    
-and then says "In the first form, the Allocator value used is copied from 
-str.get_allocator().", which isn't an option according to 21.3.1.
-
    
 
    [
-Batavia:  We need blanket statement to the effect of:
+2009-04-28 Pablo adds:
 ]
    
 
 
-
      
-
    1. If an allocator is passed in, use it, or,
      2. 
-
    2. If a string is passed in, use its allocator.
      3. 
-
    
+
    
+Tentatively-ready NAD Editorial as fixed by
+N2768.
+
    
+
 
    [
-Review constructors and functions that return a string; make sure we follow these
-rules (substr, operator+, etc.).  Howard to supply wording.
+2009-07 Frankfurt
 ]
    
 
 
-
    [
-Bo adds:  The new container constructor which takes only a size_type is not
-consistent with 23.2 [container.requirements], p9 which says in part:
-
 
    
-All other constructors for these container types take an
-Allocator& argument (20.1.2), an allocator whose value type
-is the same as the container's value type. A copy of this argument is
-used for any memory allocation performed, by these constructors and by
-all member functions, during the lifetime of each container object.
+Fixed by N2768.
 
    
-]
    
-
 
 
    [
-post Bellevue: We re-confirm that the issue is real. Pablo will provide wording.
+2009-07-28 Reopened by Alisdair.  No longer solved by concepts.
 ]
    
 
 
@@ -6884,1689 +5545,2147 @@ post Bellevue: We re-confirm that the issue is real. Pablo will provide wording.
 
 
    Proposed resolution:
    
 
    
+Change X [allocator.requirements]:
+
    
+
+
    
+
    
+r : a value of type X::reference obtained by the expression *p.
+
    
+
    
+s : a value of type X::const_reference obtained by the 
+expression *q or by conversion from a value r.
 
    
+
    
+
+
    [
+post Oxford:  This would be rendered NAD Editorial by acceptance of
+N2257.
+]
    
+
+
+
    [
+Kona (2007):  This issue is section 8 of N2387.  There was some discussion of it but
+no resolution to this issue was recorded.  Moved to Open.
+]
    
+
+
 
 
 
 
 
 
    
-
    617. std::array is a sequence that doesn't satisfy the sequence requirements?
    
-
    Section: 23.3.1 [array] Status: Open
- Submitter: Bo Persson Opened: 2006-12-30  Last modified: 2008-03-14
    
-
    View other active issues in [array].
    
-
    View all other issues in [array].
    
-
    View all issues with Open status.
    
+
    659. istreambuf_iterator should have an operator->()
    
+
    Section: 24.6.3 [istreambuf.iterator] Status: Ready
+ Submitter: Niels Dekker Opened: 2007-03-25  Last modified: 2009-07-15
    
+
    View all other issues in [istreambuf.iterator].
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
 
    
-The <array> header is given under 23.3 [sequences].
-23.3.1 [array]/paragraph 3 says:
+Greg Herlihy has clearly demonstrated that a user defined input
+iterator should have an operator->(), even if its
+value type is a built-in type (comp.std.c++, "Re: Should any iterator
+have an operator->() in C++0x?", March 2007).  And as Howard
+Hinnant remarked in the same thread that the input iterator
+istreambuf_iterator doesn't have one, this must be a
+defect!
 
    
-
    
-"Unless otherwise specified, all array operations are as described in
-23.2 [container.requirements]".
-
    
 
    
-However, array isn't mentioned at all in section 23.2 [container.requirements].
-In particular, Table 82 "Sequence requirements" lists several operations (insert, erase, clear) 
-that std::array does not have in 23.3.1 [array].
+Based on Greg's example, the following code demonstrates the issue:
+
     #include <iostream> 
+ #include <fstream>
+ #include <streambuf> 
+
+ typedef char C;
+ int main ()
+ {
+   std::ifstream s("filename", std::ios::in);
+   std::istreambuf_iterator<char> i(s);
+
+   (*i).~C();  // This is well-formed...
+   i->~C();  // ... so this should be supported!
+ }
+
    
+
+
    
+Of course, operator-> is also needed when the value_type of
+istreambuf_iterator is a class.
 
    
 
    
-Also, Table 83 "Optional sequence operations" lists several operations that 
-std::array does have, but array isn't mentioned.
+The operator-> could be implemented in various ways.  For instance,
+by storing the current value inside the iterator, and returning its
+address.  Or by returning a proxy, like operator_arrow_proxy, from
+http://www.boost.org/boost/iterator/iterator_facade.hpp
+
    
+
    
+I hope that the resolution of this issue will contribute to getting a
+clear and consistent definition of iterator concepts.
 
    
 
+
    [
+Kona (2007): The proposed resolution is inconsistent because the return
+type of istreambuf_iterator::operator->() is specified to be pointer,
+but the proposed text also states that "operator-> may return a proxy."
+]
    
+
 
-
    Proposed resolution:
    
+
    [
+Niels Dekker (mailed to Howard Hinnant):
+]
    
+
+
    
 
    
+The proposed resolution does
+not seem inconsistent to me. istreambuf_iterator::operator->() should
+have istreambuf_iterator::pointer as return type, and this return type
+may in fact be a proxy.
 
    
+
    
+AFAIK, the resolution of 445 ("iterator_traits::reference
+unspecified for some iterator categories") implies that for any iterator
+class Iter, the return type of operator->() is Iter::pointer, by
+definition.  I don't think Iter::pointer needs to be a raw pointer.
+
    
+
    
+Still I wouldn't mind if the text "operator-> may return a proxy" would
+be removed from the resolution. I think it's up to the library
+implementation, how to implement istreambuf_iterator::operator->().  As
+longs as it behaves as expected: i->m should have the same effect as
+(*i).m. Even for an explicit destructor call, i->~C().  The main issue
+is just: istreambuf_iterator should have an operator->()!
+
    
+
    
 
+
    [
+2009-04-30 Alisdair adds:
+]
    
 
 
+
    
+Note that operator-> is now a requirement in the InputIterator concept, so
+this issue cannot be ignored or existing valid programs will break when
+compiled with an 0x library.
+
    
 
+
    [
+2009-05-29 Alisdair adds:
+]
    
 
-
    
-
    625. mixed up Effects and Returns clauses
    
-
    Section: 17 [library] Status: Open
- Submitter: Martin Sebor Opened: 2007-01-20  Last modified: 2009-05-23
    
-
    View other active issues in [library].
    
-
    View all other issues in [library].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
- 
    
-
-Many member functions of basic_string are overloaded,
-with some of the overloads taking a string argument,
-others value_type*, others size_type, and
-others still iterators. Often, the requirements on one of
-the overloads are expressed in the form of Effects,
-Throws, and in the Working Paper
-(N2134)
-also Remark clauses, while those on the rest of the overloads
-via a reference to this overload and using a Returns clause.
-
    
 
+
    
 
    
-The difference between the two forms of specification is that per
-17.5.1.4 [structure.specifications], p3, an Effects clause specifies
-"actions performed by the functions," i.e., its observable
-effects, while a Returns clause is "a description of the
-return value(s) of a function" that does not impose any
-requirements on the function's observable effects.
+I agree with the observation that in principle the type 'pointer' may be a
+proxy, and the words highlighting this are redundant.
 
    
-
 
    
-Since only Notes are explicitly defined to be informative and
-all other paragraphs are explicitly defined to be normative, like
-Effects and Returns, the new Remark clauses also
-impose normative requirements.
+However, in the current draught pointer is required to be exactly 'charT *'
+by the derivation from std::iterator.  At a minimum, the 4th parameter of
+this base class template should become unspecified.  That permits the
+introduction of a proxy as a nested class in some further undocumented (not
+even exposition-only) base.
 
    
-
 
    
-So by this strict reading of the standard there are some member
-functions of basic_string that are required to throw an
-exception under some conditions or use specific traits members while
-many other otherwise equivalent overloads, while obliged to return the
-same values, aren't required to follow the exact same requirements
-with regards to the observable effects.
+It also permits the istream_iterator approach where the cached value is
+stored in the iterator itself, and the iterator serves as its own proxy for
+post-increment operator++ - removing the need for the existing
+exposition-only nested class proxy.
 
    
-
 
    
-Here's an example of this problem that was precipitated by the change
-from informative Notes to normative Remarks (presumably made to
-address 424):
+Note that the current proxy class also has exactly the right properties to
+serve as the pointer proxy too.  This is likely to be a common case where an
+InputIterator does not hold internal state but delegates to another class.
 
    
-
 
    
-In the Working Paper, find(string, size_type) contains a
-Remark clause (which is just a Note in the current
-standard) requiring it to use traits::eq().
+Proposed Resolution:
 
    
-
 
    
-find(const charT *s, size_type pos) is specified to
-return find(string(s), pos) by a Returns clause
-and so it is not required to use traits::eq(). However,
-the Working Paper has replaced the original informative Note
-about the function using traits::length() with a
-normative requirement in the form of a Remark. Calling
-traits::length() may be suboptimal, for example when the
-argument is a very long array whose initial substring doesn't appear
-anywhere in *this.
+In addition to the current proposal:
 
    
-
 
    
-Here's another similar example, one that existed even prior to the
-introduction of Remarks:
+24.6.3 [istreambuf.iterator]
 
    
+
    template<class charT, class traits = char_traits<charT> >
+class istreambuf_iterator
+  : public iterator<input_iterator_tag, charT,
+                    typename traits::off_type, charT* unspecified, charT> {
+
    
+
    
 
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
 
    
- insert(size_type pos, string, size_type, size_type) is
-required to throw out_of_range if pos >
-size().
+Move the additional part into the proposed resolution, and wrap the
+descriptive text in a Note.
 
    
+
    [Howard: done.]
    
 
 
    
-insert(size_type pos, string str) is specified to return
-insert(pos, str, 0, npos) by a Returns clause and
-so its effects when pos > size() are strictly speaking
-unspecified.
-
    
-
+Move to Ready.
 
    
-I believe a careful review of the current Effects and
-Returns clauses is needed in order to identify all such
-problematic cases. In addition, a review of the Working Paper should
-be done to make sure that the newly introduced normative Remark
-clauses do not impose any undesirable normative requirements in place
-of the original informative Notes.
-
+
    
 
-
    [
-Batavia: Alan and Pete to work.
-]
    
 
 
-
    [
-Bellevue: Marked as NAD Editorial.
-]
    
+
    Proposed resolution:
    
+
    
+Add to the synopsis in 24.6.3 [istreambuf.iterator]:
+
    
 
+
    charT operator*() const;
+pointer operator->() const;
+istreambuf_iterator<charT,traits>& operator++();
+
    
 
-
    [
-Post-Sophia Antipolis:
-Martin indicates there is still work to be done on this issue.
-Reopened.
-]
    
-
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-Tom proposes we say that, unless specified otherwise,
-it is always the caller's responsibility to verify that supplied arguments
-meet the called function's requirements.
-If further semantics are specified
-(e.g., that the function throws under certain conditions),
-then it is up to the implementer to check those conditions.
-Alan feels strongly that our current use of Requires in this context
-is confusing, especially now that requires is a new keyword.
-
    
+
    
+24.6.3 [istreambuf.iterator]
+
    
 
+
    template<class charT, class traits = char_traits<charT> >
+class istreambuf_iterator
+  : public iterator<input_iterator_tag, charT,
+                    typename traits::off_type, charT* unspecified, charT> {
+
    
 
-
    Proposed resolution:
    
 
    
+Change 24.6.3 [istreambuf.iterator], p1:
 
    
 
+
    
+The class template istreambuf_iterator reads successive
+characters from the streambuf for which it was constructed.
+operator* provides access to the current input character, if
+any. [Note: operator-> may return a proxy. —
+end note] Each time
+operator++ is evaluated, the iterator advances to the next
+input character. If the end of stream is reached
+(streambuf_type::sgetc() returns traits::eof()), the
+iterator becomes equal to the end of stream iterator value. The default
+constructor istreambuf_iterator() and the constructor
+istreambuf_iterator(0) both construct an end of stream iterator
+object suitable for use as an end-of-range.
+
    
 
 
 
 
-
    
-
    630. arrays of valarray
    
-
    Section: 26.6.2.1 [valarray.cons] Status: Open
- Submitter: Martin Sebor Opened: 2007-01-28  Last modified: 2008-06-02
    
-
    View other active issues in [valarray.cons].
    
-
    View all other issues in [valarray.cons].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-        
    
 
-Section 26.2 [numeric.requirements], p1     suggests     that     a
-valarray  specialization on  a  type T  that
-satisfies  the requirements enumerated  in the  paragraph is  itself a
-valid  type   on  which  valarray   may  be  instantiated
-(Footnote       269        makes       this       clear).        I.e.,
-valarray<valarray<T>  > is  valid as  long as
-T   is   valid.    However,  since   implementations   of
-valarray are permitted to initialize storage allocated by
-the class by  invoking the default ctor of  T followed by
-the    copy    assignment    operator,   such    implementations    of
-valarray   wouldn't  work  with   (perhaps  user-defined)
-specializations of valarray whose assignment operator had
-undefined behavior when the size of its argument didn't match the size
-of *this.  By "wouldn't work" I mean that it would
-be  impossible  to resize  such  an array  of  arrays  by calling  the
-resize() member  function on it if the  function used the
-copy  assignment operator  after constructing  all elements  using the
-default  ctor (e.g.,  by invoking  new  value_type[N]) to
-obtain default-initialized storage) as it's permitted to do.
 
-        
    
-        
    
 
-Stated      more     generally,      the      problem     is      that
-valarray<valarray<T>  >::resize(size_t) isn't
-required or  guaranteed to have well-defined semantics  for every type
-T     that      satisfies     all     requirements     in
-26.2 [numeric.requirements].
+
    
+
    668. money_get's empty minus sign
    
+
    Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: Review
+ Submitter: Thomas Plum Opened: 2007-04-16  Last modified: 2009-07-20
    
+
    View other active issues in [locale.money.get.virtuals].
    
+
    View all other issues in [locale.money.get.virtuals].
    
+
    View all issues with Review status.
    
+
    Discussion:
    
+
    
+22.4.6.1.2 [locale.money.get.virtuals], para 3 says:
+
    
 
-        
    
-        
    
+
    
+If pos or neg is empty, the sign component is
+optional, and if no sign is detected, the result is given the sign
+that corresponds to the source of the empty string.
+
    
 
-I  believe  this  problem  was  introduced  by  the  adoption  of  the
-resolution                outlined                in                N0857,
-Assignment  of  valarrays,  from  1996.   The  copy  assignment
-operator  of  the original  numerical  array  classes  proposed in  N0280,
-as      well       as      the      one       proposed      in      N0308
-(both  from 1993), had  well-defined semantics  for arrays  of unequal
-size (the  latter explicitly  only when *this  was empty;
-assignment of non empty arrays of unequal size was a runtime error).
+
    
+The following objection has been raised:
+
    
 
-        
    
-        
    
+
    
+A negative_sign of "" means "there is no
+way to write a negative sign" not "any null sequence is a negative
+sign, so it's always there when you look for it".
+
    
 
-The  justification for  the  change given  in  N0857 was the "loss  of
-performance [deemed]  only significant  for very simple  operations on
-small arrays or for architectures with very few registers."
+
    
+[Plum ref _222612Y32]
+
    
 
-        
    
-        
    
+
    [
+Kona (2007): Bill to provide proposed wording and interpretation of existing wording.
+]
    
 
-Since tiny  arrays on a  limited subset of hardware  architectures are
-likely  to  be  an   exceedingly  rare  case  (despite  the  continued
-popularity of  x86) I  propose to revert  the resolution and  make the
-behavior    of   all   valarray    assignment   operators
-well-defined even  for non-conformal  arrays (i.e., arrays  of unequal
-size).   I have implemented  this change  and measured  no significant
-degradation  in performance in  the common  case (non-empty  arrays of
-equal size).  I  have measured a 50% (and in  some cases even greater)
-speedup  in the  case of  assignments to  empty arrays  versus calling
-resize()  first followed  by  an invocation  of the  copy
-assignment operator.
 
-        
    
+
    
+Related to 669.
+
    
 
 
    [
-Bellevue:
+2009-05-17 Howard adds:
 ]
    
 
 
 
    
-If no proposed wording by June meeting, this issue should be closed NAD.
+
    
+I disagree that a negative_sign of "" means "there is no
+way to
+write a negative sign". The meaning requires the sentences of
+22.4.6.1.2 [locale.money.get.virtuals] p3 following that quoted above
+to be
+taken into account:
+
    
+
+
    
+-3- ... If pos or neg is empty, the sign component is
+optional, and if no sign is detected, the result is given the sign that
+corresponds to the source of the empty string. Otherwise, the character
+in the indicated position must match the first character of pos
+or neg, and the result is given the corresponding sign. If the
+first character of pos is equal to the first character of
+neg, or if both strings are empty, the result is given a
+positive sign.
 
    
 
+
    
+So a negative_sign of "" means "there is no way to write a
+negative sign" only when positive_sign is also "".  However
+when negative_sign is "" and postive_sign.size() >
+0, then one writes a negative value by not writing the
+postive_sign in the position indicated by
+money_base::sign.
+For example:
+
    
 
+
    pattern = {symbol, sign, value, none}
+positive_sign = "+"
+negative_sign = ""
+$123   // a negative value, using optional sign
+$+123  // a positive value
+$-123  // a parse error
+
    
 
-
    Proposed resolution:
    
-        
    
+
    
+And:
+
    
 
-Change 26.6.2.2 [valarray.assign], p1 as follows:
+
    pattern = {symbol, sign, value, none}
+positive_sign = ""
+negative_sign = ""
+$123   // a positive value, no sign possible
+$+123  // a parse error
+$-123  // a parse error
+
    
 
-        
    
-        
    
-            
    
-                
 
-valarray<T>& operator=(const valarray<T>& x);
+
    
+And (regarding 669):
+
    
 
-                
-            
    
-            
    
+
    pattern = {symbol, sign, value, none}
+positive_sign = "-"
+negative_sign = "-"
+$123   // a parse error, sign is mandatory
+$+123  // a parse error
+$-123  // a positive value
+
    
 
--1- Each element of the *this array is assigned the value
-of  the  corresponding  element   of  the  argument  array.   The
-resulting behavior is undefined if When the length of
-the  argument  array  is  not   equal  to  the  length  of  the  *this
-array.  resizes  *this  to make  the  two
-arrays     the      same     length,     as      if     by     calling
-resize(x.size()), before performing the assignment.
 
-            
    
-        
    
-        
    
+
    
+The text seems both unambiguous and clear to me.  I recommend NAD for
+both this issue and 669.  However I would have no
+objection to adding examples such as those above.
+
    
+
    
 
-And  add a new  paragraph just  below paragraph  1 with  the following
-text:
+
    [
+Batavia (2009-05):
+]
    
 
-        
    
-        
    
-            
    
+
    
+
    
+This discussion applies equally to issue 669 (q.v.).
+Howard has added examples above,
+and recommends either NAD or a resolution that adds his (or similar) examples
+to the Working Paper.
+
    
+
    
+Alan would like to rewrite paragraph 3.
+
    
+
    
+We recommend moving to NAD.
+Anyone who feels strongly about adding the examples
+is invited to submit corresponding wording.
+We further recommend issue 669 be handled identically.
+
    
+
    
 
--2- Postcondition: size() == x.size().
+
    [
+2009-07-14 Alan reopens with improved wording.
+]
    
 
-            
    
-        
    
-        
    
 
-Also add the following paragraph to 26.6.2.2 [valarray.assign], immediately after p4:
+
    [
+2009-07 Frankfurt
+]
    
 
-        
    
-        
    
-            
    
 
--?- When the length,  N of the array referred
-to by the  argument is not equal to  the length of *this,
-the  operator resizes *this  to make  the two  arrays the
-same  length, as if  by calling  resize(N), before
-performing the assignment.
-
-            
    
-        
    
+
    
+No consensus for closing as NAD.  Leave in Review.
+
    
 
-
    [
-pre-Sophia Antipolis, Martin adds the following compromise wording, but
-prefers the original proposed resolution:
-]
    
 
 
+
    Proposed resolution:
    
 
    
-Change 26.6.2.2 [valarray.assign], p1 as follows:
+Change 22.4.6.1.2 [locale.money.get.virtuals] p3:
 
    
 
 
    
-
    
- -1- Requires: size() == 0 || size() == x.size().
-
    
-
    
- -2- Effects: If size() == 0 calls x.resize(x.size()) first.
-     Each element of the *this array is assigned the value of the
-     corresponding element of the argument array.
-
    
-
    
- -3- Postcondition: size() == x.size().
-
    
-
    
-
-
    
-Add the following paragraph to 26.6.2.2 [valarray.assign], immediately after
-p4:
-
    
+-3- If the first character (if any) in the string pos returned by
+mp.positive_sign() or the string neg returned by
+mp.negative_sign() is recognized in the position indicated by
+sign in the format pattern, it is consumed and any remaining characters
+in the string are required after all the other format components.
+[Example: If showbase is off�, then for a neg
+value of "()" and a currency symbol of "L", in "(100 L)" the "L" is
+consumed; but if neg is "-", the "L" in "-100 L" is not
+consumed. -- end example] If pos or neg is
+empty, the sign component is optional, and if no sign is detected, the
+result is given the sign that corresponds to the source of the empty
+string. Otherwise, the character in the indicated position must match
+the first character of pos or neg, and the result is
+given the corresponding sign. If the first character of pos is
+equal to the first character of neg, or if both strings are
+empty, the result is given a positive sign.
 
-
    
-
    
- -?- When size() == 0 and the length, N of the array referred to by
-     the argument is not equal to the length of *this, the operator
-     resizes *this to make the two arrays the same length, as if by
-     calling resize(N), before performing the assignment. Otherwise,
-     when size() > 0 and size() != N, the behavior is undefined.
-
    
+The sign pattern strings pos and neg are returned by
+mp.positive_sign() and mp.negative_sign() respectively. A sign pattern
+is matched if its first character is recognized in s in the position
+indicated by sign in the format pattern, or if the pattern is empty and
+there is no sign recognized in s. A match is required to occur. If both
+patterns are matched, the result is given a positive sign, otherwise the
+result is given the sign corresponding to the matched pattern. 
+If the pattern contains more than one character, the characters after the first 
+must be matched in s after all other format components. 
+If any sign
+characters are matched, s is consumed up to and including those characters.
+[Example: If showbase is off, then for a neg
+value of "()" and a currency symbol of "L", in
+"(100 L)" the entire string is consumed; but for a neg
+value of "-", in "-100 L", the string is consumed
+through the second "0" (the space and "L" are not consumed). — end
+example] 
 
    
 
 
 
-
    [
-Kona (2007): Gaby to propose wording for an alternative resolution in
-which you can assign to a valarray of size 0, but not to any other
-valarray whose size is unequal to the right hand side of the assignment.
-]
    
-
-
-
 
 
 
    
-
    632. Time complexity of size() for std::set
    
-
    Section: 23.2 [container.requirements] Status: Open
- Submitter: Lionel B Opened: 2007-02-01  Last modified: 2009-05-23
    
-
    View other active issues in [container.requirements].
    
-
    View all other issues in [container.requirements].
    
-
    View all issues with Open status.
    
+
    671. precision of hexfloat
    
+
    Section: 22.4.2.2.2 [facet.num.put.virtuals] Status: Review
+ Submitter: John Salmon Opened: 2007-04-20  Last modified: 2009-07-26
    
+
    View other active issues in [facet.num.put.virtuals].
    
+
    View all other issues in [facet.num.put.virtuals].
    
+
    View all issues with Review status.
    
 
    Discussion:
    
 
    
-A recent news group discussion:
+I am trying to understand how TR1 supports hex float (%a) output.
 
    
-
    
 
    
-Anyone know if the Standard has anything to say about the time complexity
-of size() for std::set?   I need to access a set's size (/not/ to know if it is empty!) heavily
-during an algorithm and was thus wondering whether I'd be better off
-tracking the size "manually" or whether that'd be pointless.
+As far as I can tell, it does so via the following:
 
    
 
    
-That would be pointless. size() is O(1).
+8.15 Additions to header <locale> [tr.c99.locale]
 
    
 
    
-Nit: the standard says "should" have constant time. Implementations may take
-license to do worse. I know that some do this for std::list<> as a part of
-some trade-off with other operation.
+In subclause 22.4.2.2.2 [facet.num.put.virtuals], Table 58 Floating-point conversions, after
+the line:
+floatfield == ios_base::scientific %E
 
    
-
 
    
-I was aware of that, hence my reluctance to use size() for std::set.
+add the two lines:
 
    
+
    floatfield == ios_base::fixed | ios_base::scientific && !uppercase %a
+floatfield == ios_base::fixed | ios_base::scientific %A 2
+
    
 
    
-However, this reason would not apply to std::set<> as far as I can see.
+[Note: The additional requirements on print and scan functions, later
+in this clause, ensure that the print functions generate hexadecimal
+floating-point fields with a %a or %A conversion specifier, and that
+the scan functions match hexadecimal floating-point fields with a %g
+conversion specifier.  end note]
 
    
 
    
-Ok, I guess the only option is to try it and see...
+Following the thread, in 22.4.2.2.2 [facet.num.put.virtuals], we find:
 
    
-
    
-
 
    
-If I have any recommendation to the C++ Standards Committee it is that
-implementations must (not "should"!) document clearly[1], where known, the
-time complexity of *all* container access operations.
+For conversion from a floating-point type, if (flags & fixed) != 0 or
+if str.precision() > 0, then str.precision() is specified in the
+conversion specification.
 
    
 
    
-[1] In my case (gcc 4.1.1) I can't swear that the time complexity of size()
-for std::set is not documented... but if it is it's certainly well hidden
-away.
+This would seem to imply that when floatfield == fixed|scientific, the
+precision of the conversion specifier is to be taken from
+str.precision().  Is this really what's intended?  I sincerely hope
+that I'm either missing something or this is an oversight.  Please
+tell me that the committee did not intend to mandate that hex floats
+(and doubles) should by default be printed as if by %.6a.
 
    
 
 
    [
-Kona (2007): This issue affects all the containers. We'd love to see a
-paper dealing with the broad issue. We think that the complexity of the
-size() member of every container -- except possibly list -- should be
-O(1). Alan has volunteered to provide wording.
+Howard: I think the fundamental issue we overlooked was that with %f,
+%e, %g, the default precision was always 6.  With %a the default
+precision is not 6, it is infinity.  So for the first time, we need to
+distinguish between the default value of precision, and the precision
+value 6.
 ]
    
 
 
 
    [
-Bellevue:
+2009-07 Frankfurt
 ]
    
 
 
 
    
-Mandating O(1) size will not fly, too many implementations would be
-invalidated. Alan to provide wording that toughens wording, but that
-does not absolutely mandate O(1).
-
    
+
    
+Leave this open for Robert and Daniel to work on.
+
    
+
    
+Straw poll: Disposition?
+
    
+
      
+
    • Default is %.6a (i.e. NAD): 2
      • 
+
    • Always %a (no precision): 6
      • 
+
    • precision(-1) == %a: 3
      • 
+
    
+
    
+Daniel and Robert have direction to write up wording for the "always %a" solution.
+
    
 
 
    [
-Batavia (2009-05):
+2009-07-15 Robert provided wording.
 ]
    
 
-
    
-We observed that the wording "should" (in note a) has no effect.
-Howard prefers that O(1) size be mandated.
-It is not clear that this issue can be resolved to everyone's satisfaction,
-but Alan will provide wording nonetheless.
 
    
 
 
+
 
    Proposed resolution:
    
 
    
+Change 22.4.2.2.2 [facet.num.put.virtuals], Stage 1, under p5 (near the end
+of Stage 1):
 
    
 
+
    
+For conversion from a floating-point type, str.precision() is specified
+as precision in the conversion specification
+if floatfield != (ios_base::fixed | ios_base::scientific), else no
+precision is specified.
+
    
+
+
+
+
    [
+Kona (2007): Robert volunteers to propose wording.
+]
    
+
 
 
 
 
 
    
-
    635. domain of allocator::address
    
-
    Section: X [allocator.requirements] Status: Open
- Submitter: Howard Hinnant Opened: 2007-02-08  Last modified: 2009-05-01
    
-
    View other active issues in [allocator.requirements].
    
-
    View all other issues in [allocator.requirements].
    
+
    676. Moving the unordered containers
    
+
    Section: 23.5 [unord] Status: Open
+ Submitter: Howard Hinnant Opened: 2007-05-05  Last modified: 2009-07-28
    
+
    View all other issues in [unord].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-The table of allocator requirements in X [allocator.requirements] describes
-allocator::address as:
-
    
-
    a.address(r)
-a.address(s)
-
    
-
    
-where r and s are described as:
+Move semantics are missing from the unordered containers.  The proposed
+resolution below adds move-support consistent with
+N1858
+and the current working draft.
 
    
-
    
-a value of type X::reference obtained by the expression *p. 
-
    
 
 
    
-and p is 
+The current proposed resolution simply lists the requirements for each function.
+These might better be hoisted into the requirements table for unordered associative containers.
+Futhermore a mild reorganization of the container requirements could well be in order.
+This defect report is purposefully ignoring these larger issues and just focusing
+on getting the unordered containers "moved".
 
    
 
-
    
-a value of type X::pointer, obtained by calling a1.allocate, 
-where a1 == a
-
    
+
    [
+2009-07-28 Reopened by Alisdair.  No longer solved by concepts.
+]
    
 
-
    
-This all implies that to get the address of some value of type T that
-value must have been allocated by this allocator or a copy of it.
-
    
 
-
    
-However sometimes container code needs to compare the address of an external value of
-type T with an internal value.  For example list::remove(const T& t)
-may want to compare the address of the external value t with that of a value
-stored within the list.  Similarly vector or deque insert may
-want to make similar comparisons (to check for self-referencing calls).
-
    
+
+
+
    Proposed resolution:
    
 
 
    
-Mandating that allocator::address can only be called for values which the
-allocator allocated seems overly restrictive.
+Add to 23.5 [unord]:
 
    
 
-
    [
-post San Francisco:
-]
    
+
    template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_map<Key, T, Hash, Pred, Alloc>& y); 
 
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_map<Key, T, Hash, Pred, Alloc>&& y);
 
-
    
-Pablo recommends NAD Editorial, solved by
-N2768.
-
    
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_map<Key, T, Hash, Pred, Alloc>&& x, 
+            unordered_map<Key, T, Hash, Pred, Alloc>& y);
 
-
    [
-2009-04-28 Pablo adds:
-]
    
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
 
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_multimap<Key, T, Hash, Pred, Alloc>&& y);
 
-
    
-Tentatively-ready NAD Editorial as fixed by
-N2768.
-
    
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>&& x, 
+            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
 
+...
 
+template <class Value, class Hash, class Pred, class Alloc> 
+  void swap(unordered_set<Value, Hash, Pred, Alloc>& x, 
+            unordered_set<Value, Hash, Pred, Alloc>& y); 
 
-
    Proposed resolution:
    
-
    
-Change X [allocator.requirements]:
-
    
+template <class Value, class Hash, class Pred, class Alloc> 
+  void swap(unordered_set<Value, Hash, Pred, Alloc>& x, 
+            unordered_set<Value, Hash, Pred, Alloc>&& y);
 
-
    
-
    
-r : a value of type X::reference obtained by the expression *p.
-
    
-
    
-s : a value of type X::const_reference obtained by the 
-expression *q or by conversion from a value r.
-
    
-
    
+template <class Value, class Hash, class Pred, class Alloc> 
+  void swap(unordered_set<Value, Hash, Pred, Alloc>&& x, 
+            unordered_set<Value, Hash, Pred, Alloc>& y);
 
-
    [
-post Oxford:  This would be rendered NAD Editorial by acceptance of
-N2257.
-]
    
+template <class Value, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multiset<Value, Hash, Pred, Alloc>& x, 
+            unordered_multiset<Value, Hash, Pred, Alloc>& y);
 
+template <class Value, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multiset<Value, Hash, Pred, Alloc>& x, 
+            unordered_multiset<Value, Hash, Pred, Alloc>&& y);
 
-
    [
-Kona (2007):  This issue is section 8 of N2387.  There was some discussion of it but
-no resolution to this issue was recorded.  Moved to Open.
-]
    
+template <class Value, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multiset<Value, Hash, Pred, Alloc>&& x, 
+            unordered_multiset<Value, Hash, Pred, Alloc>& y);
+
    
 
+
    unordered_map
    
 
+
    
+Change 23.5.1 [unord.map]:
+
    
 
+
    class unordered_map
+{
+    ...
+    unordered_map(const unordered_map&);
+    unordered_map(unordered_map&&);
+    ~unordered_map();
+    unordered_map& operator=(const unordered_map&);
+    unordered_map& operator=(unordered_map&&);
+    ...
+    // modifiers 
+    std::pair<iterator, bool> insert(const value_type& obj); 
+    template <class P> pair<iterator, bool> insert(P&& obj);
+    iterator       insert(iterator hint, const value_type& obj);
+    template <class P> iterator       insert(iterator hint, P&& obj);
+    const_iterator insert(const_iterator hint, const value_type& obj);
+    template <class P> const_iterator insert(const_iterator hint, P&& obj);
+    ...
+    void swap(unordered_map&&);
+    ...
+    mapped_type& operator[](const key_type& k);
+    mapped_type& operator[](key_type&& k);
+    ...
+};
 
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_map<Key, T, Hash, Pred, Alloc>& y);
 
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_map<Key, T, Hash, Pred, Alloc>&& y);
 
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_map<Key, T, Hash, Pred, Alloc>&& x, 
+            unordered_map<Key, T, Hash, Pred, Alloc>& y);
+
    
 
-
    
-
    644. Possible typos in 'function' description
    
-
    Section: 20.7.16.2 [func.wrap.func] Status: Tentatively NAD
- Submitter: Bo Persson Opened: 2007-02-25  Last modified: 2009-05-23
    
-
    View other active issues in [func.wrap.func].
    
-
    View all other issues in [func.wrap.func].
    
-
    View all issues with Tentatively NAD status.
    
-
    Discussion:
    
 
    
-20.7.16.2 [func.wrap.func]
+Add to 23.5.1.1 [unord.map.cnstr]:
 
    
+
+
    
+
    template <class InputIterator>
+  unordered_map(InputIterator f, InputIterator l, 
+                size_type n = implementation-defined, 
+                const hasher& hf = hasher(), 
+                const key_equal& eql = key_equal(), 
+                const allocator_type& a = allocator_type());
+
    
+
+
    
+
+Requires: If the iterator's dereference operator returns an
+lvalue or a const rvalue pair<key_type, mapped_type>,
+then both key_type and mapped_type shall be
+CopyConstructible.
+
+
    
+
    
+
 
    
-The note in paragraph 2 refers to 'undefined void operators', while the
-section declares a pair of operators returning bool.
+Add to 23.5.1.2 [unord.map.elem]:
 
    
 
-
    [
-Post-Sophia Antipolis:
-]
    
+
    
 
+
    mapped_type& operator[](const key_type& k);
    
 
 
    
-Changed from Pending WP to Open.  This issue was voted to WP at the same time the operators were
-changed from private to deleted.  The two issues stepped on each other.  What do we want the return
-type of these deleted functions to be?
+
    ...
    
+
    
+Requires: key_type shall be CopyConstructible
+and mapped_type shall be DefaultConstructible.
+
    
 
    
 
-
    [
-2009-05-02 Daniel adds:
-]
    
-
+
    mapped_type& operator[](key_type&& k);
    
 
 
    
-
    
-I suggest harmonizing this issue with similar classes. E.g. in
-20.8.13.3 [util.smartptr.weak] bool return values for
-
    
-
    template <class Y> bool operator<(weak_ptr<Y> const&) const = delete;
-template <class Y> bool operator<=(weak_ptr<Y> const&) const = delete;
-template <class Y> bool operator>(weak_ptr<Y> const&) const = delete;
-template <class Y> bool operator>=(weak_ptr<Y> const&) const = delete;
-
    
+
    
+Effects: If the unordered_map does not already contain an
+element whose key is equivalent to k , inserts the value
+std::pair<const key_type, mapped_type>(std::move(k), mapped_type()).
+
    
+
+
    
+Requires: mapped_type shall be DefaultConstructible.
+
    
+
+
    
+Returns: A reference to x.second, where x is the
+(unique) element whose key is equivalent to k.
+
    
+
+
    
 
-
    
-are used and basically all newer provided deleted copy assignment operators
-of type X use the canonical return type X& instead of void. Since the note
-mentioned in the issue description has now already been changed to
-
    
-
    
-deleted overloads close possible hole in the type system
 
    
+
 
    
-it seems to be of even lesser need to perform the change. Therefore
-I recommend declaring the issue as NAD.
+Add new section [unord.map.modifiers]:
 
    
-
    
 
-
    [
-Batavia (2009-05):
-]
    
+
    
+
    pair<iterator, bool> insert(const value_type& x);
+template <class P> pair<iterator, bool> insert(P&& x);
+iterator       insert(iterator hint, const value_type& x);
+template <class P> iterator       insert(iterator hint, P&& x);
+const_iterator insert(const_iterator hint, const value_type& x);
+template <class P> const_iterator insert(const_iterator hint, P&& x);
+template <class InputIterator>
+  void insert(InputIterator first, InputIterator last);
+
    
 
 
    
-
    
-We agree with Daniel's recommendation.
-
    
-
    
-Move to NAD.
-
    
+
    
+Requires: Those signatures taking a const value_type& parameter
+requires both the key_type and the mapped_type to be
+CopyConstructible.
+
    
+
+
    
+P shall be convertible to value_type.
+ If P is instantiated as a reference
+type, then the argument x is copied from. Otherwise x
+is considered to be an rvalue as it is converted to value_type
+and inserted into the unordered_map. Specifically, in such
+cases CopyConstructible is not required of key_type or
+mapped_type unless the conversion from P specifically
+requires it (e.g. if P is a tuple<const key_type,
+mapped_type>, then key_type must be
+CopyConstructible).
+
    
+
+
    
+The signature taking InputIterator
+parameters requires CopyConstructible of both
+key_type and mapped_type if the dereferenced
+InputIterator returns an lvalue or const rvalue
+value_type.
+
    
+
 
    
 
+
    
 
-
    Proposed resolution:
    
 
    
-Change 20.7.16.2 [func.wrap.func]
+Add to 23.5.1.3 [unord.map.swap]:
 
    
 
-
    ...
-private:
-   // 20.7.16.2 [func.wrap.func], undefined operators:
-   template<class Function2> bool void operator==(const function<Function2>&);
-   template<class Function2> bool void operator!=(const function<Function2>&);
-};
-
    
+
    
+
    template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_map<Key, T, Hash, Pred, Alloc>& y);
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_map<Key, T, Hash, Pred, Alloc>&& y);
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_map<Key, T, Hash, Pred, Alloc>&& x, 
+            unordered_map<Key, T, Hash, Pred, Alloc>& y);
+
    
+
    
+
+
    unordered_multimap
    
 
 
    
-Change 20.7.16.2 [func.wrap.func]
+Change 23.5.2 [unord.multimap]:
 
    
 
-
    template<class Function2> bool void operator==(const function<Function2>&);
-template<class Function2> bool void operator!=(const function<Function2>&);
-
    
-
+
    class unordered_multimap
+{
+    ...
+    unordered_multimap(const unordered_multimap&);
+    unordered_multimap(unordered_multimap&&);
+    ~unordered_multimap();
+    unordered_multimap& operator=(const unordered_multimap&);
+    unordered_multimap& operator=(unordered_multimap&&);
+    ...
+    // modifiers 
+    iterator insert(const value_type& obj); 
+    template <class P> iterator insert(P&& obj);
+    iterator       insert(iterator hint, const value_type& obj);
+    template <class P> iterator       insert(iterator hint, P&& obj);
+    const_iterator insert(const_iterator hint, const value_type& obj);
+    template <class P> const_iterator insert(const_iterator hint, P&& obj);
+    ...
+    void swap(unordered_multimap&&);
+    ...
+};
 
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
 
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_multimap<Key, T, Hash, Pred, Alloc>&& y);
 
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>&& x, 
+            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
+
    
 
-
    
-
    659. istreambuf_iterator should have an operator->()
    
-
    Section: 24.6.3 [istreambuf.iterator] Status: Open
- Submitter: Niels Dekker Opened: 2007-03-25  Last modified: 2009-05-30
    
-
    View all other issues in [istreambuf.iterator].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
 
    
-Greg Herlihy has clearly demonstrated that a user defined input
-iterator should have an operator->(), even if its
-value type is a built-in type (comp.std.c++, "Re: Should any iterator
-have an operator->() in C++0x?", March 2007).  And as Howard
-Hinnant remarked in the same thread that the input iterator
-istreambuf_iterator doesn't have one, this must be a
-defect!
+Add to 23.5.2.1 [unord.multimap.cnstr]:
 
    
-
    
-Based on Greg's example, the following code demonstrates the issue:
-
     #include <iostream> 
- #include <fstream>
- #include <streambuf> 
-
- typedef char C;
- int main ()
- {
-   std::ifstream s("filename", std::ios::in);
-   std::istreambuf_iterator<char> i(s);
 
-   (*i).~C();  // This is well-formed...
-   i->~C();  // ... so this should be supported!
- }
+
    
+
    template <class InputIterator>
+  unordered_multimap(InputIterator f, InputIterator l, 
+                size_type n = implementation-defined, 
+                const hasher& hf = hasher(), 
+                const key_equal& eql = key_equal(), 
+                const allocator_type& a = allocator_type());
 
    
 
+
    
+
+Requires: If the iterator's dereference operator returns an
+lvalue or a const rvalue pair<key_type, mapped_type>,
+then both key_type and mapped_type shall be
+CopyConstructible.
+
+
    
+
    
+
 
    
-Of course, operator-> is also needed when the value_type of
-istreambuf_iterator is a class.
-
    
-
    
-The operator-> could be implemented in various ways.  For instance,
-by storing the current value inside the iterator, and returning its
-address.  Or by returning a proxy, like operator_arrow_proxy, from
-http://www.boost.org/boost/iterator/iterator_facade.hpp
-
    
-
    
-I hope that the resolution of this issue will contribute to getting a
-clear and consistent definition of iterator concepts.
+Add new section [unord.multimap.modifiers]:
 
    
 
-
    [
-Kona (2007): The proposed resolution is inconsistent because the return
-type of istreambuf_iterator::operator->() is specified to be pointer,
-but the proposed text also states that "operator-> may return a proxy."
-]
    
+
    
+
    iterator insert(const value_type& x);
+template <class P> iterator       insert(P&& x);
+iterator       insert(iterator hint, const value_type& x);
+template <class P> iterator       insert(iterator hint, P&& x);
+const_iterator insert(const_iterator hint, const value_type& x);
+template <class P> const_iterator insert(const_iterator hint, P&& x);
+template <class InputIterator>
+  void insert(InputIterator first, InputIterator last);
+
    
 
+
    
+
    
+Requires: Those signatures taking a const value_type& parameter
+requires both the key_type and the mapped_type to be
+CopyConstructible.
+
    
 
-
    [
-Niels Dekker (mailed to Howard Hinnant):
-]
    
+
    
+P shall be convertible to value_type.
+ If P is instantiated as a reference
+type, then the argument x is copied from. Otherwise x
+is considered to be an rvalue as it is converted to value_type
+and inserted into the unordered_multimap. Specifically, in such
+cases CopyConstructible is not required of key_type or
+mapped_type unless the conversion from P specifically
+requires it (e.g. if P is a tuple<const key_type,
+mapped_type>, then key_type must be
+CopyConstructible).
+
    
 
-
    
-
    
-The proposed resolution does
-not seem inconsistent to me. istreambuf_iterator::operator->() should
-have istreambuf_iterator::pointer as return type, and this return type
-may in fact be a proxy.
-
    
-
    
-AFAIK, the resolution of 445 ("iterator_traits::reference
-unspecified for some iterator categories") implies that for any iterator
-class Iter, the return type of operator->() is Iter::pointer, by
-definition.  I don't think Iter::pointer needs to be a raw pointer.
-
    
-
    
-Still I wouldn't mind if the text "operator-> may return a proxy" would
-be removed from the resolution. I think it's up to the library
-implementation, how to implement istreambuf_iterator::operator->().  As
-longs as it behaves as expected: i->m should have the same effect as
-(*i).m. Even for an explicit destructor call, i->~C().  The main issue
-is just: istreambuf_iterator should have an operator->()!
-
    
+
    
+The signature taking InputIterator
+parameters requires CopyConstructible of both
+key_type and mapped_type if the dereferenced
+InputIterator returns an lvalue or const rvalue
+value_type.
+
    
 
    
 
-
    [
-2009-04-30 Alisdair adds:
-]
    
+
    
 
+
    
+Add to 23.5.2.2 [unord.multimap.swap]:
+
    
 
 
    
-Note that operator-> is now a requirement in the InputIterator concept, so
-this issue cannot be ignored or existing valid programs will break when
-compiled with an 0x library.
+
    template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_multimap<Key, T, Hash, Pred, Alloc>&& y);
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>&& x, 
+            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
+
    
 
    
 
-
    [
-2009-05-29 Alisdair adds:
-]
    
-
+
    unordered_set
    
 
-
    
-
    
-I agree with the observation that in principle the type 'pointer' may be a
-proxy, and the words highlighting this are redundant.
-
    
-
    
-However, in the current draught pointer is required to be exactly 'charT *'
-by the derivation from std::iterator.  At a minimum, the 4th parameter of
-this base class template should become unspecified.  That permits the
-introduction of a proxy as a nested class in some further undocumented (not
-even exposition-only) base.
-
    
-
    
-It also permits the istream_iterator approach where the cached value is
-stored in the iterator itself, and the iterator serves as its own proxy for
-post-increment operator++ - removing the need for the existing
-exposition-only nested class proxy.
-
    
-
    
-Note that the current proxy class also has exactly the right properties to
-serve as the pointer proxy too.  This is likely to be a common case where an
-InputIterator does not hold internal state but delegates to another class.
-
    
 
    
-Proposed Resolution:
-
    
-
    
-In addition to the current proposal:
+Change 23.5.3 [unord.set]:
 
    
-
    
-24.6.3 [istreambuf.iterator]
-
    
-
    template<class charT, class traits = char_traits<charT> >
-class istreambuf_iterator
-  : public iterator<input_iterator_tag, charT,
-                    typename traits::off_type, charT* unspecified, charT> {
-
    
-
    
 
+
    class unordered_set
+{
+    ...
+    unordered_set(const unordered_set&);
+    unordered_set(unordered_set&&);
+    ~unordered_set();
+    unordered_set& operator=(const unordered_set&);
+    unordered_set& operator=(unordered_set&&);
+    ...
+    // modifiers 
+    std::pair<iterator, bool> insert(const value_type& obj); 
+    pair<iterator, bool> insert(value_type&& obj);
+    iterator       insert(iterator hint, const value_type& obj);
+    iterator       insert(iterator hint, value_type&& obj);
+    const_iterator insert(const_iterator hint, const value_type& obj);
+    const_iterator insert(const_iterator hint, value_type&& obj);
+    ...
+    void swap(unordered_set&&);
+    ...
+};
+
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_set<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_set<Key, T, Hash, Pred, Alloc>& y);
 
-
    Proposed resolution:
    
-
    
-Add to the synopsis in 24.6.3 [istreambuf.iterator]:
-
    
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_set<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_set<Key, T, Hash, Pred, Alloc>&& y);
 
-
    charT operator*() const;
-pointer operator->() const;
-istreambuf_iterator<charT,traits>& operator++();
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_set<Key, T, Hash, Pred, Alloc>&& x, 
+            unordered_set<Key, T, Hash, Pred, Alloc>& y);
 
    
 
 
    
-Change 24.6.3 [istreambuf.iterator], p1:
+Add to 23.5.3.1 [unord.set.cnstr]:
 
    
 
+
    
+
    template <class InputIterator>
+  unordered_set(InputIterator f, InputIterator l, 
+                size_type n = implementation-defined, 
+                const hasher& hf = hasher(), 
+                const key_equal& eql = key_equal(), 
+                const allocator_type& a = allocator_type());
+
    
+
 
    
-The class template istreambuf_iterator reads successive
-characters from the streambuf for which it was constructed.
-operator* provides access to the current input character, if
-any. operator-> may return a proxy. Each time
-operator++ is evaluated, the iterator advances to the next
-input character. If the end of stream is reached
-(streambuf_type::sgetc() returns traits::eof()), the
-iterator becomes equal to the end of stream iterator value. The default
-constructor istreambuf_iterator() and the constructor
-istreambuf_iterator(0) both construct an end of stream iterator
-object suitable for use as an end-of-range.
+
+Requires: If the iterator's dereference operator returns an
+lvalue or a const rvalue value_type, then the
+value_type shall be CopyConstructible.
+
 
    
+
    
 
+
    
+Add new section [unord.set.modifiers]:
+
    
+
+
    
+
    pair<iterator, bool> insert(const value_type& x);
+pair<iterator, bool> insert(value_type&& x);
+iterator       insert(iterator hint, const value_type& x);
+iterator       insert(iterator hint, value_type&& x);
+const_iterator insert(const_iterator hint, const value_type& x);
+const_iterator insert(const_iterator hint, value_type&& x);
+template <class InputIterator>
+  void insert(InputIterator first, InputIterator last);
+
    
 
+
    
 
+
    
+Requires: Those signatures taking a const
+value_type& parameter requires the value_type to
+be CopyConstructible.
+
    
 
+
    
+The signature taking InputIterator parameters requires
+CopyConstructible of value_type if the dereferenced
+InputIterator returns an lvalue or const rvalue
+value_type.
+
    
 
+
    
 
+
    
 
-
    
-
    667. money_get's widened minus sign
    
-
    Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: Tentatively NAD
- Submitter: Thomas Plum Opened: 2007-04-16  Last modified: 2009-05-23
    
-
    View other active issues in [locale.money.get.virtuals].
    
-
    View all other issues in [locale.money.get.virtuals].
    
-
    View all issues with Tentatively NAD status.
    
-
    Discussion:
    
 
    
-22.4.6.1.2 [locale.money.get.virtuals], para 1 says:
+Add to 23.5.3.2 [unord.set.swap]:
 
    
 
-
    
-The result is returned as an integral value
-stored in units or as a sequence of digits possibly preceded by a
-minus sign (as produced by ct.widen(c) where c is '-' or in the range
-from '0' through '9', inclusive) stored in digits.
-
    
+
    
+
    template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_set<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_set<Key, T, Hash, Pred, Alloc>& y);
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_set<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_set<Key, T, Hash, Pred, Alloc>&& y);
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_set<Key, T, Hash, Pred, Alloc>&& x, 
+            unordered_set<Key, T, Hash, Pred, Alloc>& y);
+
    
+
    
+
+
    unordered_multiset
    
+
+
    
+Change 23.5.4 [unord.multiset]:
+
    
+
+
    class unordered_multiset
+{
+    ...
+    unordered_multiset(const unordered_multiset&);
+    unordered_multiset(unordered_multiset&&);
+    ~unordered_multiset();
+    unordered_multiset& operator=(const unordered_multiset&);
+    unordered_multiset& operator=(unordered_multiset&&);
+    ...
+    // modifiers 
+    iterator insert(const value_type& obj); 
+    iterator insert(value_type&& obj);
+    iterator       insert(iterator hint, const value_type& obj);
+    iterator       insert(iterator hint, value_type&& obj);
+    const_iterator insert(const_iterator hint, const value_type& obj);
+    const_iterator insert(const_iterator hint, value_type&& obj);
+    ...
+    void swap(unordered_multiset&&);
+    ...
+};
+
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_multiset<Key, T, Hash, Pred, Alloc>& y);
+
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_multiset<Key, T, Hash, Pred, Alloc>&& y);
+
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>&& x, 
+            unordered_multiset<Key, T, Hash, Pred, Alloc>& y);
+
    
 
 
    
-The following
-objection has been raised:
+Add to 23.5.4.1 [unord.multiset.cnstr]:
 
    
 
+
    
+
    template <class InputIterator>
+  unordered_multiset(InputIterator f, InputIterator l, 
+                size_type n = implementation-defined, 
+                const hasher& hf = hasher(), 
+                const key_equal& eql = key_equal(), 
+                const allocator_type& a = allocator_type());
+
    
+
 
    
-Some implementations interpret this to mean that a facet derived from
-ctype<wchar_t> can provide its own member do_widen(char)
-which produces e.g. L'@' for the "widened" minus sign, and that the
-'@' symbol will appear in the resulting sequence of digits.  Other
-implementations have assumed that one or more places in the standard permit the
-implementation to "hard-wire" L'-' as the "widened" minus sign.  Are
-both interpretations permissible, or only  one?
+
+Requires: If the iterator's dereference operator returns an
+lvalue or a const rvalue value_type, then the
+value_type shall be CopyConstructible.
+
 
    
+
    
 
 
    
-[Plum ref _222612Y14]
+Add new section [unord.multiset.modifiers]:
 
    
 
+
    
+
    iterator insert(const value_type& x);
+iterator insert(value_type&& x);
+iterator       insert(iterator hint, const value_type& x);
+iterator       insert(iterator hint, value_type&& x);
+const_iterator insert(const_iterator hint, const value_type& x);
+const_iterator insert(const_iterator hint, value_type&& x);
+template <class InputIterator>
+  void insert(InputIterator first, InputIterator last);
+
    
+
+
    
+
+
    
+Requires: Those signatures taking a const
+value_type& parameter requires the value_type to
+be CopyConstructible.
+
    
+
+
    
+The signature taking InputIterator parameters requires
+CopyConstructible of value_type if the dereferenced
+InputIterator returns an lvalue or const rvalue
+value_type.
+
    
+
+
    
+
+
    
+
 
    
-Furthermore: if ct.widen('9') produces L'X' (a non-digit), does a
-parse fail if a '9' appears in the subject string? [Plum ref _22263Y33]
+Add to 23.5.4.2 [unord.multiset.swap]:
 
    
 
+
    
+
    template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_multiset<Key, T, Hash, Pred, Alloc>& y);
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>& x, 
+            unordered_multiset<Key, T, Hash, Pred, Alloc>&& y);
+template <class Key, class T, class Hash, class Pred, class Alloc> 
+  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>&& x, 
+            unordered_multiset<Key, T, Hash, Pred, Alloc>& y);
+
    
+
    
+
+
+
 
    [
-Kona (2007): Bill and Dietmar to provide proposed wording.
+Voted to WP in Bellevue.
 ]
    
 
 
 
    [
-post Bellevue: Bill adds:
+post Bellevue, Pete notes:
 ]
    
 
 
 
    
-The Standard is clear that the minus sign stored in digits is ct.widen('-').
-The subject string must contain characters c in the set [-0123456789]
-which are translated by ct.widen(c) calls before being stored in digits;
-the widened characters are not relevant to the parsing of the subject string.
+
    
+Please remind people who are reviewing issues to check that the text
+modifications match the current draft. Issue 676, for example, adds two
+overloads for unordered_map::insert taking a hint. One takes a
+const_iterator and returns a const_iterator, and the other takes an
+iterator and returns an iterator. This was correct at the time the issue
+was written, but was changed in Toronto so there is only one hint
+overload, taking a const_iterator and returning an iterator.
+
    
+
    
+This issue is not ready. In addition to the relatively minor signature
+problem I mentioned earlier, it puts requirements in the wrong places.
+Instead of duplicating requirements throughout the template
+specifications, it should put them in the front matter that talks about
+requirements for unordered containers in general. This presentation
+problem is editorial, but I'm not willing to do the extensive rewrite
+that it requires. Please put it back into Open status.
+
    
 
    
 
+
    Rationale:
    
 
    [
-Batavia (2009-05):
+San Francisco:
 ]
    
 
+
 
    
-We agree with Bill's comment above,
-in line with the first of the interpretations offered in the issue.
-Move to NAD.
+Solved by
+N2776.
 
    
 
 
-
    Proposed resolution:
    
-
    
-
    
-
 
 
 
 
 
    
-
    668. money_get's empty minus sign
    
-
    Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: Tentatively NAD
- Submitter: Thomas Plum Opened: 2007-04-16  Last modified: 2009-05-23
    
-
    View other active issues in [locale.money.get.virtuals].
    
-
    View all other issues in [locale.money.get.virtuals].
    
-
    View all issues with Tentatively NAD status.
    
+
    696. istream::operator>>(int&) broken
    
+
    Section: 27.7.1.2.2 [istream.formatted.arithmetic] Status: Ready
+ Submitter: Martin Sebor Opened: 2007-06-23  Last modified: 2009-07-15
    
+
    View all other issues in [istream.formatted.arithmetic].
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
 
    
-22.4.6.1.2 [locale.money.get.virtuals], para 3 says:
+From message c++std-lib-17897:
 
    
-
-
    
-If pos or neg is empty, the sign component is
-optional, and if no sign is detected, the result is given the sign
-that corresponds to the source of the empty string.
-
    
-
 
    
-The following objection has been raised:
+The code shown in 27.7.1.2.2 [istream.formatted.arithmetic] as the "as if"
+implementation of the two arithmetic extractors that don't have a
+corresponding num_get interface (i.e., the
+short and int overloads) is subtly buggy in
+how it deals with EOF, overflow, and other similar
+conditions (in addition to containing a few typos).
 
    
-
-
    
-A negative_sign of "" means "there is no
-way to write a negative sign" not "any null sequence is a negative
-sign, so it's always there when you look for it".
-
    
-
 
    
-[Plum ref _222612Y32]
+One problem is that if num_get::get() reaches the EOF
+after reading in an otherwise valid value that exceeds the limits of
+the narrower type (but not LONG_MIN or
+LONG_MAX), it will set err to
+eofbit. Because of the if condition testing for
+(err == 0), the extractor won't set
+failbit (and presumably, return a bogus value to the
+caller).
+
    
+
    
+Another problem with the code is that it never actually sets the
+argument to the extracted value. It can't happen after the call to
+setstate() since the function may throw, so we need to
+show when and how it's done (we can't just punt as say: "it happens
+afterwards"). However, it turns out that showing how it's done isn't
+quite so easy since the argument is normally left unchanged by the
+facet on error except when the error is due to a misplaced thousands
+separator, which causes failbit to be set but doesn't
+prevent the facet from storing the value.
 
    
 
 
    [
-Kona (2007): Bill to provide proposed wording and interpretation of existing wording.
+Batavia (2009-05):
 ]
    
 
-
+
    
+
    
+We believe this part of the Standard has been recently adjusted
+and that this issue was addressed during that rewrite.
+
    
 
    
-Related to 669.
+Move to NAD.
 
    
+
    
 
 
    [
-2009-05-17 Howard adds:
+2009-05-28 Howard adds:
 ]
    
 
 
 
    
 
    
-I disagree that a negative_sign of "" means "there is no
-way to
-write a negative sign". The meaning requires the sentences of
-22.4.6.1.2 [locale.money.get.virtuals] p3 following that quoted above
-to be
-taken into account:
+I've moved this issue from Tentatively NAD to Open.
 
    
 
-
    
--3- ... If pos or neg is empty, the sign component is
-optional, and if no sign is detected, the result is given the sign that
-corresponds to the source of the empty string. Otherwise, the character
-in the indicated position must match the first character of pos
-or neg, and the result is given the corresponding sign. If the
-first character of pos is equal to the first character of
-neg, or if both strings are empty, the result is given a
-positive sign.
-
    
-
 
    
-So a negative_sign of "" means "there is no way to write a
-negative sign" only when positive_sign is also "".  However
-when negative_sign is "" and postive_sign.size() >
-0, then one writes a negative value by not writing the
-postive_sign in the position indicated by
-money_base::sign.
-For example:
+The current wording of
+N2857
+in 22.4.2.1.2 [facet.num.get.virtuals] p3, stage 3 appears to indicate that
+in parsing arithmetic types, the value is always set, but sometimes in addition
+to setting failbit.
 
    
 
-
    pattern = {symbol, sign, value, none}
-positive_sign = "+"
-negative_sign = ""
-$123   // a negative value, using optional sign
-$+123  // a positive value
-$-123  // a parse error
-
    
+
      
+
    • 
+If there is a range error, the value is set to min or max, else
+
      • 
+
    • 
+if there is a conversion error, the value is set to 0, else
+
      • 
+
    • 
+if there is a grouping error, the value is set to whatever it would be if grouping were ignored, else
+
      • 
+
    • 
+the value is set to its error-free result.
+
      • 
+
    
 
 
    
-And:
+However there is a contradictory sentence in 22.4.2.1.2 [facet.num.get.virtuals] p1.
 
    
 
-
    pattern = {symbol, sign, value, none}
-positive_sign = ""
-negative_sign = ""
-$123   // a positive value, no sign possible
-$+123  // a parse error
-$-123  // a parse error
-
    
-
-
 
    
-And (regarding 669):
+27.7.1.2.2 [istream.formatted.arithmetic] should mimic the behavior of 22.4.2.1.2 [facet.num.get.virtuals]
+(whatever we decide that behavior is) for
+int and short, and currently does not.  I believe that the
+correct code fragment should look like:
 
    
 
-
    pattern = {symbol, sign, value, none}
-positive_sign = "-"
-negative_sign = "-"
-$123   // a parse error, sign is mandatory
-$+123  // a parse error
-$-123  // a positive value
+
    typedef num_get<charT,istreambuf_iterator<charT,traits> > numget;
+iostate err = ios_base::goodbit;
+long lval;
+use_facet<numget>(loc).get(*this, 0, *this, err, lval);
+if (lval < numeric_limits<int>::min())
+{
+  err |= ios_base::failbit;
+  val = numeric_limits<int>::min();
+}
+else if (lval > numeric_limits<int>::max())
+{
+  err |= ios_base::failbit;
+  val = numeric_limits<int>::max();
+}
+else
+  val = static_cast<int>(lval);
+setstate(err);
 
    
-
-
-
    
-The text seems both unambiguous and clear to me.  I recommend NAD for
-both this issue and 669.  However I would have no
-objection to adding examples such as those above.
-
    
 
    
 
 
    [
-Batavia (2009-05):
+2009-07 Frankfurt
 ]
    
 
+
 
    
+Move to Ready.
+
    
+
+
+
+
    Proposed resolution:
    
 
    
-This discussion applies equally to issue 669 (q.v.).
-Howard has added examples above,
-and recommends either NAD or a resolution that adds his (or similar) examples
-to the Working Paper.
+Change 22.4.2.1.2 [facet.num.get.virtuals], p1:
 
    
+
+
    
+-1- Effects: Reads characters from in, interpreting them
+according to str.flags(), use_facet<ctype<charT>
+>(loc), and use_facet< numpunct<charT>
+>(loc), where loc is str.getloc(). If an error
+occurs, val is unchanged; otherwise it is set to the resulting value.
+
    
+
 
    
-Alan would like to rewrite paragraph 3.
+Change 27.7.1.2.2 [istream.formatted.arithmetic], p2 and p3:
 
    
+
+
    
+
    operator>>(short& val);
+
    
+
    
 
    
-We recommend moving to NAD.
-Anyone who feels strongly about adding the examples
-is invited to submit corresponding wording.
-We further recommend issue 669 be handled identically.
+-2- The conversion occurs as if performed by the following code fragment (using the same notation as for 
+the preceding code fragment):
 
    
-
    
 
+
    typedef num_get<charT,istreambuf_iterator<charT,traits> > numget;
+iostate err = iostate_base::goodbit;
+long lval;
+use_facet<numget>(loc).get(*this, 0, *this, err, lval);
+if (err != 0)
+  ;
+else if (lval < numeric_limits<short>::min()
+  || numeric_limits<short>::max() < lval)
+     err = ios_base::failbit;
+if (lval < numeric_limits<short>::min())
+{
+  err |= ios_base::failbit;
+  val = numeric_limits<short>::min();
+}
+else if (lval > numeric_limits<short>::max())
+{
+  err |= ios_base::failbit;
+  val = numeric_limits<short>::max();
+}
+else
+  val = static_cast<short>(lval);
+setstate(err);
+
    
 
+
    
 
-
    Proposed resolution:
    
+
    operator>>(int& val);
+
    
+
    
 
    
+-3- The conversion occurs as if performed by the following code fragment (using the same notation as for 
+the preceding code fragment):
 
    
 
+
    typedef num_get<charT,istreambuf_iterator<charT,traits> > numget;
+iostate err = iostate_base::goodbit;
+long lval;
+use_facet<numget>(loc).get(*this, 0, *this, err, lval);
+if (err != 0)
+  ;
+else if (lval < numeric_limits<int>::min()
+  || numeric_limits<int>::max() < lval)
+     err = ios_base::failbit;
+if (lval < numeric_limits<int>::min())
+{
+  err |= ios_base::failbit;
+  val = numeric_limits<int>::min();
+}
+else if (lval > numeric_limits<int>::max())
+{
+  err |= ios_base::failbit;
+  val = numeric_limits<int>::max();
+}
+else
+  val = static_cast<int>(lval);
+setstate(err);
+
    
+
+
    
+
+
    
+
 
 
 
 
 
    
-
    669. Equivalent postive and negative signs in money_get
    
-
    Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: Tentatively NAD
- Submitter: Thomas Plum Opened: 2007-04-16  Last modified: 2009-05-23
    
-
    View other active issues in [locale.money.get.virtuals].
    
-
    View all other issues in [locale.money.get.virtuals].
    
-
    View all issues with Tentatively NAD status.
    
+
    704. MoveAssignable requirement for container value type overly strict
    
+
    Section: 23.2 [container.requirements] Status: Open
+ Submitter: Howard Hinnant Opened: 2007-05-20  Last modified: 2009-07-20
    
+
    View other active issues in [container.requirements].
    
+
    View all other issues in [container.requirements].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-22.4.6.1.2 [locale.money.get.virtuals], para 3 sentence 4 says:
+The move-related changes inadvertently overwrote the intent of 276.
+Issue 276 removed the requirement of CopyAssignable from
+most of the member functions of node-based containers.  But the move-related changes
+unnecessarily introduced the MoveAssignable requirement for those members which used to
+require CopyAssignable.
 
    
 
-
    
-If the first character of pos is equal to the first character of neg, 
-or if both strings are empty, the result is given a positive sign.
-
    
-
 
    
-One interpretation is that an input sequence must match either the
-positive pattern or the negative pattern, and then in either event it
-is interpreted as positive.  The following objections has been raised:
+We also discussed (c++std-lib-18722) the possibility of dropping MoveAssignable
+from some of the sequence requirements.  Additionally the in-place construction
+work may further reduce requirements.  For purposes of an easy reference, here are the
+minimum sequence requirements as I currently understand them.  Those items in requirements
+table in the working draft which do not appear below have been purposefully omitted for
+brevity as they do not have any requirements of this nature.  Some items which do not
+have any requirements of this nature are included below just to confirm that they were
+not omitted by mistake.
 
    
 
-
    
-The input can successfully match only a positive sign, so the negative
-pattern is an unsuccessful match.
-
    
+
+
+
+
+
+
+
+
    Container Requirements
    X u(a)value_type must be CopyConstructible
    X u(rv)array and containers with a propagate_never allocator require value_type to be MoveConstructible
    a = uSequences require value_type to be CopyConstructible and CopyAssignable.
+                               Associative containers require value_type to be CopyConstructible.
    a = rvarray requires value_type to be MoveAssignable.
+                                Sequences and Associative containers with propagate_never and propagate_on_copy_construction allocators require value_type to be MoveConstructible.
    swap(a,u)array and containers with propagate_never and
+                  propagate_on_copy_construction allocators require value_type to be Swappable.
    
 
 
    
-[Plum ref _222612Y34, 222612Y51b]
 
    
 
-
    [
-Bill to provide proposed wording and interpretation of existing wording.
-]
    
-
-
-
    [
-2009-05-17 See Howard's comments in related issue 668.
-]
    
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
    Sequence Requirements
    X(n)value_type must be DefaultConstructible
    X(n, t)value_type must be CopyConstructible
    X(i, j)If the iterators return an lvalue the value_type must be CopyConstructible.
+                                 If the iterators return an rvalue the value_type must be MoveConstructible.
    a.insert(p, t)The value_type must be CopyConstructible.
+                                        The sequences vector and deque also require the value_type to be CopyAssignable.
    a.insert(p, rv)The value_type must be MoveConstructible.
+                                        The sequences vector and deque also require the value_type to be MoveAssignable.
    a.insert(p, n, t)The value_type must be CopyConstructible.
+                                        The sequences vector and deque also require the value_type to be CopyAssignable.
    a.insert(p, i, j)If the iterators return an lvalue the value_type must be CopyConstructible.
+                                        The sequences vector and deque also require the value_type to be CopyAssignable when the iterators return an lvalue.
+                                        If the iterators return an rvalue the value_type must be MoveConstructible.
+                                        The sequences vector and deque also require the value_type to be MoveAssignable when the iterators return an rvalue.
    a.erase(p)The sequences vector and deque require the value_type to be MoveAssignable.
    a.erase(q1, q2)The sequences vector and deque require the value_type to be MoveAssignable.
    a.clear()
    a.assign(i, j)If the iterators return an lvalue the value_type must be CopyConstructible and CopyAssignable.
+                                        If the iterators return an rvalue the value_type must be MoveConstructible and MoveAssignable.
    a.assign(n, t)The value_type must be CopyConstructible and CopyAssignable.
    a.resize(n)The value_type must be DefaultConstructible.
+                                     The sequence vector also requires the value_type to be MoveConstructible.
    a.resize(n, t)The value_type must be CopyConstructible.
    
 
+
    
+
    
 
-
    [
-Batavia (2009-05):
-]
    
+
+
+
+
+
+
+
+
+
+
+
+
+
    Optional Sequence Requirements
    a.front()
    a.back()
    a.push_front(t)The value_type must be CopyConstructible.
    a.push_front(rv)The value_type must be MoveConstructible.
    a.push_back(t)The value_type must be CopyConstructible.
    a.push_back(rv)The value_type must be MoveConstructible.
    a.pop_front()
    a.pop_back()
    a[n]
    a.at[n]
    
 
-
    
 
    
-This discussion applies equally to issue 668 (q.v.).
-Howard has added examples there,
-and recommends either NAD or a resolution that adds his (or similar) examples
-to the Working Paper.
 
    
+
+
+
+
+
+
+
+
+
+
+
+
    Associative Container Requirements
    X(i, j)If the iterators return an lvalue the value_type must be CopyConstructible.
+                                 If the iterators return an rvalue the value_type must be MoveConstructible.
    a_uniq.insert(t)The value_type must be CopyConstructible.
    a_uniq.insert(rv)The key_type and the mapped_type (if it exists) must be MoveConstructible.
    a_eq.insert(t)The value_type must be CopyConstructible.
    a_eq.insert(rv)The key_type and the mapped_type (if it exists) must be MoveConstructible.
    a.insert(p, t)The value_type must be CopyConstructible.
    a.insert(p, rv)The key_type and the mapped_type (if it exists) must be MoveConstructible.
    a.insert(i, j)If the iterators return an lvalue the value_type must be CopyConstructible.
+                                        If the iterators return an rvalue the key_type and the mapped_type (if it exists) must be MoveConstructible..
    
+
 
    
-We recommend moving to NAD.
-Anyone who feels strongly about adding the examples
-is invited to submit corresponding wording.
-We further recommend issue 668 be handled identically.
 
    
-
    
 
+
+
+
+
+
+
+
+
+
+
+
    Unordered Associative Container Requirements
    X(i, j, n, hf, eq)If the iterators return an lvalue the value_type must be CopyConstructible.
+                                 If the iterators return an rvalue the value_type must be MoveConstructible.
    a_uniq.insert(t)The value_type must be CopyConstructible.
    a_uniq.insert(rv)The key_type and the mapped_type (if it exists) must be MoveConstructible.
    a_eq.insert(t)The value_type must be CopyConstructible.
    a_eq.insert(rv)The key_type and the mapped_type (if it exists) must be MoveConstructible.
    a.insert(p, t)The value_type must be CopyConstructible.
    a.insert(p, rv)The key_type and the mapped_type (if it exists) must be MoveConstructible.
    a.insert(i, j)If the iterators return an lvalue the value_type must be CopyConstructible.
+                                        If the iterators return an rvalue the key_type and the mapped_type (if it exists) must be MoveConstructible..
    
 
-
    Proposed resolution:
    
 
    
 
    
 
+
+
+
+
+
    Miscellaneous Requirements
    map[lvalue-key]The key_type must be CopyConstructible.
+                                         The mapped_type must be DefaultConstructible and MoveConstructible.
    map[rvalue-key]The key_type must be MoveConstructible.
+                                         The mapped_type must be DefaultConstructible and MoveConstructible.
    
+
+
    [
+Kona (2007): Howard and Alan to update requirements table in issue with emplace signatures.
+]
    
+
 
+
    [
+Bellevue: This should be handled as part of the concepts work.
+]
    
 
 
+
    [
+2009-07-20 Reopened by Howard:
+]
    
 
-
    
-
    671. precision of hexfloat
    
-
    Section: 22.4.2.2.2 [facet.num.put.virtuals] Status: Open
- Submitter: John Salmon Opened: 2007-04-20  Last modified: 2009-03-12
    
-
    View all other issues in [facet.num.put.virtuals].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    
-I am trying to understand how TR1 supports hex float (%a) output.
-
    
-
    
-As far as I can tell, it does so via the following:
-
    
-
    
-8.15 Additions to header <locale> [tr.c99.locale]
-
    
-
    
-In subclause 22.4.2.2.2 [facet.num.put.virtuals], Table 58 Floating-point conversions, after
-the line:
-floatfield == ios_base::scientific %E
-
    
-
    
-add the two lines:
-
    
-
    floatfield == ios_base::fixed | ios_base::scientific && !uppercase %a
-floatfield == ios_base::fixed | ios_base::scientific %A 2
-
    
+
+
    
 
    
-[Note: The additional requirements on print and scan functions, later
-in this clause, ensure that the print functions generate hexadecimal
-floating-point fields with a %a or %A conversion specifier, and that
-the scan functions match hexadecimal floating-point fields with a %g
-conversion specifier.  end note]
+This is one of the issues that was "solved by concepts" and is now no longer solved.
 
    
+
 
    
-Following the thread, in 22.4.2.2.2 [facet.num.put.virtuals], we find:
+In a nutshell, concepts adopted the "minimum requirements" philosophy outlined
+in the discussion of this issue, and enforced it.  My strong suggestion is that
+we translate the concepts specification into documentation for the containers.
 
    
+
 
    
-For conversion from a floating-point type, if (flags & fixed) != 0 or
-if str.precision() > 0, then str.precision() is specified in the
-conversion specification.
+What this means for vendors is that they will have to implement container members
+being careful to only use those characteristics of a type that the concepts specification
+formally allowed.  Note that I am not talking about enable_if'ing
+everything.  I am simply suggesting that (for example) we tell the vendor he can't call T's
+copy constructor or move constructor within the emplace member function, etc.
 
    
+
 
    
-This would seem to imply that when floatfield == fixed|scientific, the
-precision of the conversion specifier is to be taken from
-str.precision().  Is this really what's intended?  I sincerely hope
-that I'm either missing something or this is an oversight.  Please
-tell me that the committee did not intend to mandate that hex floats
-(and doubles) should by default be printed as if by %.6a.
+What this means for customers is that they will be able to use types within C++03
+containers which are sometimes not CopyConstructible, and sometimes not even
+MoveConstructible, etc.
 
    
-
-
    [
-Howard: I think the fundamental issue we overlooked was that with %f,
-%e, %g, the default precision was always 6.  With %a the default
-precision is not 6, it is infinity.  So for the first time, we need to
-distinguish between the default value of precision, and the precision
-value 6.
-]
    
-
+
    
 
 
 
 
    Proposed resolution:
    
-
    
-
    
 
 
+
+
    Rationale:
    
 
    [
-Kona (2007): Robert volunteers to propose wording.
+post San Francisco:
 ]
    
 
 
+
    
+Solved by
+N2776.
+
    
+
+
+
 
 
 
 
    
-
    688. reference_wrapper, cref unsafe, allow binding to rvalues
    
-
    Section: 20.7.5.1 [refwrap.const] Status: Tentatively Ready
- Submitter: Peter Dimov Opened: 2007-05-10  Last modified: 2009-05-23
    
-
    View all other issues in [refwrap.const].
    
-
    View all issues with Tentatively Ready status.
    
+
    711. Contradiction in empty shared_ptr
    
+
    Section: 20.8.10.2.5 [util.smartptr.shared.obs] Status: Ready
+ Submitter: Peter Dimov Opened: 2007-08-24  Last modified: 2009-07-17
    
+
    View all other issues in [util.smartptr.shared.obs].
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
 
    
-A reference_wrapper can be constructed from an rvalue, either by using
-the constructor, or via cref (and ref in some corner cases). This leads
-to a dangling reference being stored into the reference_wrapper object.
-Now that we have a mechanism to detect an rvalue, we can fix them to
-disallow this source of undefined behavior.
+A discussion on
+comp.std.c++
+has identified a contradiction in the shared_ptr specification.
+The note:
+
    
+
+
    
+[ Note: this constructor allows creation of an empty shared_ptr instance with a non-NULL stored pointer.
+-end note ]
+
    
+
+
    
+after the aliasing constructor
+
    
+
+
    template<class Y> shared_ptr(shared_ptr<Y> const& r, T *p);
+
    
+
+
    
+reflects the intent of
+N2351
+to, well, allow the creation of an empty shared_ptr
+with a non-NULL stored pointer.
 
    
 
 
    
-Also please see the thread starting at c++std-lib-17398 for some good discussion on this subject.
+This is contradicted by the second sentence in the Returns clause of 20.8.10.2.5 [util.smartptr.shared.obs]:
 
    
 
+
    
+
    T* get() const;
+
    
+
    
+Returns: the stored pointer. Returns a null pointer if *this is empty.
+
    
+
    
+
 
    [
-2009-05-09 Alisdair adds:
+Bellevue:
 ]
    
 
 
 
    
 
    
-Now that ref/cref are constained that T must be an ObjectType, I do not
-believe there is any risk of binding ref to a temporary (which would rely on
-deducing T to be an rvalue reference type)
+Adopt option 1 and move to review, not ready.
+
    
+
    
+There was a lot of confusion about what an empty shared_ptr is (the term
+isn't defined anywhere), and whether we have a good mental model for how
+one behaves. We think it might be possible to deduce what the definition
+should be, but the words just aren't there. We need to open an issue on
+the use of this undefined term. (The resolution of that issue might
+affect the resolution of issue 711.)
 
    
 
    
-However, the problem for cref remains, so I recommend retaining that deleted
-overload.
+The LWG is getting more uncomfortable with the aliasing proposal (N2351)
+now that we realize some of its implications, and we need to keep an eye
+on it, but there isn't support for removing this feature at this time.
 
    
 
    
 
 
    [
-2009-05-10 Howard adds:
+Sophia Antipolis:
 ]
    
 
 
 
    
 
    
-Without:
+We heard from Peter Dimov, who explained his reason for preferring solution 1.
+
    
+
    
+Because it doesn't seem to add anything. It simply makes the behavior
+for p = 0 undefined. For programmers who don't create empty pointers
+with p = 0, there is no difference. Those who do insist on creating them
+presumably have a good reason, and it costs nothing for us to define the
+behavior in this case.
+
    
+
    
+The aliasing constructor is sharp enough as it is, so "protecting" users
+doesn't make much sense in this particular case.
+
    
+
    
+> Do you have a use case for r being empty and r being non-null? 
+
    
+
    
+I have received a few requests for it from "performance-conscious"
+people (you should be familiar with this mindset) who don't like the
+overhead of allocating and maintaining a control block when a null
+deleter is used to approximate a raw pointer. It is obviously an "at
+your own risk", low-level feature; essentially a raw pointer behind a
+shared_ptr facade.
+
    
+
    
+We could not agree upon a resolution to the issue; some of us thought
+that Peter's description above is supporting an undesirable behavior.
 
    
+
    
 
-
    template <class T> void ref(const T&& t) = delete;
-
    
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
 
    
-I believe this program will compile:
+We favor option 1, move to Ready.
 
    
+
    [
+Howard:  Option 2 commented out for clarity, and can be brought back.
+]
    
 
-
    #include <functional>
+
    
 
-struct A {};
 
-const A source() {return A();}
 
-int main()
-{
-   std::reference_wrapper<const A> r = std::ref(source());
-}
-
    
+
    Proposed resolution:
    
 
    
-I.e. in:
+In keeping the N2351 spirit and obviously my preference, change 20.8.10.2.5 [util.smartptr.shared.obs]:
 
    
-
    template <ObjectType T> reference_wrapper<T> ref(T& t);
-
    
 
+
    
+
    T* get() const;
+
    
+
    
+Returns: the stored pointer. Returns a null pointer if *this is empty.
+
    
+
    
+
+
+
+
+
+
+
+
+
    
+
    716. Production in [re.grammar] not actually modified
    
+
    Section: 28.13 [re.grammar] Status: Ready
+ Submitter: Stephan T. Lavavej Opened: 2007-08-31  Last modified: 2009-07-16
    
+
    View all issues with Ready status.
    
+
    Discussion:
    
 
    
-this:
+TR1 7.13 [tr.re.grammar]/3 and C++0x WP 28.13 [re.grammar]/3 say:
 
    
 
-
    ref(source())
-
    
+
    
 
    
-deduces T as const A, and so:
+The following productions within the ECMAScript grammar are modified as follows:
 
    
 
-
    ref(const A& t)
+
    CharacterClass ::
+[ [lookahead ∉ {^}] ClassRanges ]
+[ ^ ClassRanges ]
 
    
 
+
    
+
 
    
-will bind to a temporary (tested with a pre-concepts rvalue-ref enabled compiler).
+This definition for CharacterClass appears to be exactly identical to that in ECMA-262.
 
    
+
 
    
-Therefore I think we still need the ref-protection.  I respectfully disagree with Alisdair's
-comment and am in favor of the proposed wording as it stands.  Also, CWG 606
-(noted below) has now been "favorably" resolved.
+Was an actual modification intended here and accidentally omitted, or was this production accidentally included?
 
    
 
+
    [
+Batavia (2009-05):
+]
    
+
+
    
+
    
+We agree that what is specified is identical to what ECMA-262 specifies.
+Pete would like to take a bit of time to assess whether we had intended,
+but failed, to make a change.
+It would also be useful to hear from John Maddock on the issue.
+
    
+
    
+Move to Open.
+
    
 
    
 
 
    [
-Batavia (2009-05):
+2009-07 Frankfurt:
 ]
    
 
+
 
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
+Move to Ready.
 
    
 
 
+
 
    Proposed resolution:
    
 
    
-In 20.7 [function.objects], add the following two signatures to the synopsis:
+Remove this mention of the CharacterClass production.
 
    
 
-
    template <class T> void ref(const T&& t) = delete;
-template <class T> void cref(const T&& t) = delete;
+
    CharacterClass ::
+[ [lookahead ∉ {^}] ClassRanges ]
+[ ^ ClassRanges ]
 
    
 
 
 
-
    [
-N2292
-addresses the first part of the resolution but not the second.
-]
    
-
 
-
    [
-Bellevue:  Doug noticed problems with the current wording.
-]
    
 
 
-
    [
-post Bellevue:  Howard and Peter provided revised wording.
-]
    
+
    
+
    719. std::is_literal type traits should be provided
    
+
    Section: 20.6 [meta] Status: Open
+ Submitter: Daniel Krügler Opened: 2007-08-25  Last modified: 2009-07-16
    
+
    View other active issues in [meta].
    
+
    View all other issues in [meta].
    
+
    View all issues with Open status.
    
+
    Duplicate of: 750
    
+
    Discussion:
    
+
    
+Since the inclusion of constexpr in the standard draft N2369 we have
+a new type category "literal", which is defined in 3.9 [basic.types]/p.11:
+
    
+
+
    
+
    
+-11- A type is a literal type if it is:
+
    
+
      
+
    • a scalar type; or
      • 
+
    • a class type (clause 9) with
      
+
        
+
      • a trivial copy constructor,
        • 
+
      • a trivial destructor,
        • 
+
      • at least one constexpr constructor other than the copy constructor,
        • 
+
      • no virtual base classes, and
        • 
+
      • all non-static data members and base classes of literal types; or
        • 
+
      
+
      • 
+
    • an array of literal type.
      • 
+
    
+
    
+
+
    
+I strongly suggest that the standard provides a type traits for
+literal types in 20.6.4.3 [meta.unary.prop] for several reasons:
+
    
+
+
      
+
    1. To keep the traits in sync with existing types.
      2. 
+
    2. I see many reasons for programmers to use this trait in template
+   code to provide optimized template definitions for these types,
+   see below.
      3. 
+
    3. A user-provided definition of this trait is practically impossible
+to write portably.
      4. 
+
    
+
+
    
+The special problem of reason (c) is that I don't see currently a
+way to portably test the condition for literal class types:
+
    
+
+
    
+
      
+
    • at least one constexpr constructor other than the copy constructor,
      • 
+
    
+
    
+
 
 
 
    [
-This resolution depends on a "favorable" resolution of CWG 606:  that is,
-the "special deduction rule" is disabled with the const T&& pattern.
+Alisdair is considering preparing a paper listing a number of missing
+type traits, and feels that it might be useful to handle them all
+together rather than piecemeal. This would affect issue 719 and 750.
+These two issues should move to OPEN pending AM paper on type traits.
 ]
    
 
 
+
    [
+2009-07 Frankfurt:
+]
    
 
 
+
    
+Beman, Daniel, and Alisdair will work on a paper proposing new type traits.
+
    
+
 
-
    
-
    696. istream::operator>>(int&) broken
    
-
    Section: 27.7.1.2.2 [istream.formatted.arithmetic] Status: Open
- Submitter: Martin Sebor Opened: 2007-06-23  Last modified: 2009-05-28
    
-
    View all other issues in [istream.formatted.arithmetic].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
+
    Proposed resolution:
    
 
    
-From message c++std-lib-17897:
+In 20.6.2 [meta.type.synop] in the group "type properties",
+just below the line
 
    
+
+
    template <class T> struct is_pod;
+
    
+
 
    
-The code shown in 27.7.1.2.2 [istream.formatted.arithmetic] as the "as if"
-implementation of the two arithmetic extractors that don't have a
-corresponding num_get interface (i.e., the
-short and int overloads) is subtly buggy in
-how it deals with EOF, overflow, and other similar
-conditions (in addition to containing a few typos).
+add a new one:
 
    
+
+
    template <class T> struct is_literal;
+
    
+
 
    
-One problem is that if num_get::get() reaches the EOF
-after reading in an otherwise valid value that exceeds the limits of
-the narrower type (but not LONG_MIN or
-LONG_MAX), it will set err to
-eofbit. Because of the if condition testing for
-(err == 0), the extractor won't set
-failbit (and presumably, return a bogus value to the
-caller).
+In 20.6.4.3 [meta.unary.prop], table Type Property Predicates, just
+below the line for the is_pod property add a new line:
 
    
+
+
+
+
+
+
+
+
+
+
+
    TemplateConditionPreconditions
    template <class T> struct is_literal;T is a literal type (3.9)T shall be a complete type, an
+array of unknown bound, or
+(possibly cv-qualified) void.
    
+
+
+
+
+
+
+
    
+
    723. basic_regex should be moveable
    
+
    Section: 28.8 [re.regex] Status: Ready
+ Submitter: Daniel Krügler Opened: 2007-08-29  Last modified: 2009-07-16
    
+
    View all other issues in [re.regex].
    
+
    View all issues with Ready status.
    
+
    Discussion:
    
+
+
    Addresses UK 316
    
+
 
    
-Another problem with the code is that it never actually sets the
-argument to the extracted value. It can't happen after the call to
-setstate() since the function may throw, so we need to
-show when and how it's done (we can't just punt as say: "it happens
-afterwards"). However, it turns out that showing how it's done isn't
-quite so easy since the argument is normally left unchanged by the
-facet on error except when the error is due to a misplaced thousands
-separator, which causes failbit to be set but doesn't
-prevent the facet from storing the value.
+According to the current state of the standard draft, the class
+template basic_regex, as described in 28.8 [re.regex]/3, is
+neither MoveConstructible nor MoveAssignable.
+IMO it should be, because typical regex state machines tend
+to have a rather large data quantum and I have seen several
+use cases, where a factory function returns regex values,
+which would take advantage of moveabilities.
 
    
 
 
    [
-Batavia (2009-05):
+Sophia Antipolis:
 ]
    
 
+
 
    
-
    
-We believe this part of the Standard has been recently adjusted
-and that this issue was addressed during that rewrite.
-
    
-
    
-Move to NAD.
-
    
+Needs wording for the semantics, the idea is agreed upon.
 
    
 
 
    [
-2009-05-28 Howard adds:
+Post Summit Daniel updated wording to reflect new "swap rules".
+]
    
+
+
+
    [
+2009-07 Frankfurt:
 ]
    
 
 
 
    
+Move to Ready.
+
    
+
+
+
+
    Proposed resolution:
    
 
    
-I've moved this issue from Tentatively NAD to Open.
+In the class definition of basic_regex, just below 28.8 [re.regex]/3,
+perform the following changes:
 
    
 
+
      
+
    1. 
 
      
-The current wording of
-N2857
-in 22.4.2.1.2 [facet.num.get.virtuals] p3, stage 3 appears to indicate that
-in parsing arithmetic types, the value is always set, but sometimes in addition
-to setting failbit.
+Just after basic_regex(const basic_regex&); insert:
 
      
 
-
        
-
      • 
-If there is a range error, the value is set to min or max, else
+
        basic_regex(basic_regex&&);
+
        
 
        • 
 
      • 
-if there is a conversion error, the value is set to 0, else
+
        
+Just after basic_regex& operator=(const basic_regex&); insert:
+
        
+
        basic_regex& operator=(basic_regex&&);
+
        
 
        • 
 
      • 
-if there is a grouping error, the value is set to whatever it would be if grouping were ignored, else
+
        
+Just after basic_regex& assign(const basic_regex& that); insert:
+
        
+
        basic_regex& assign(basic_regex&& that);
+
        
 
        • 
 
      • 
-the value is set to its error-free result.
-
        • 
-
      
-
 
      
-However there is a contradictory sentence in 22.4.2.1.2 [facet.num.get.virtuals] p1.
+In 28.8.2 [re.regex.construct], just after p.11 add the following
+new member definition:
 
      
-
+
      basic_regex(basic_regex&& e);
+
      
+
      
 
      
-27.7.1.2.2 [istream.formatted.arithmetic] should mimic the behavior of 22.4.2.1.2 [facet.num.get.virtuals]
-(whatever we decide that behavior is) for
-int and short, and currently does not.  I believe that the
-correct code fragment should look like:
+Effects: Move-constructs a basic_regex instance from e.
 
      
-
-
      typedef num_get<charT,istreambuf_iterator<charT,traits> > numget;
-iostate err = ios_base::goodbit;
-long lval;
-use_facet<numget>(loc).get(*this, 0, *this, err, lval);
-if (lval < numeric_limits<int>::min())
-{
-  err |= ios_base::failbit;
-  val = numeric_limits<int>::min();
-}
-else if (lval > numeric_limits<int>::max())
-{
-  err |= ios_base::failbit;
-  val = numeric_limits<int>::max();
-}
-else
-  val = static_cast<int>(lval);
-setstate(err);
-
      
-
      
-
-
-
      Proposed resolution:
      
 
      
-Change 22.4.2.1.2 [facet.num.get.virtuals], p1:
+Postconditions: flags() and mark_count() return e.flags() and
+e.mark_count(), respectively,
+that e had before construction, leaving
+e in a valid state with an unspecified value.
+
      
+
      
+Throws: nothing.
 
      
-
-
      
--1- Effects: Reads characters from in, interpreting them
-according to str.flags(), use_facet<ctype<charT>
->(loc), and use_facet< numpunct<charT>
->(loc), where loc is str.getloc(). If an error
-occurs, val is unchanged; otherwise it is set to the resulting value.
 
      
-
+
      
+
      2. 
+
    2. 
 
      
-Change 27.7.1.2.2 [istream.formatted.arithmetic], p2 and p3:
+Also in 28.8.2 [re.regex.construct], just after p.18 add the
+following new member definition:
 
      
 
-
      
-
      operator>>(short& val);
+
      basic_regex& operator=(basic_regex&& e);
 
      
 
      
+Effects: Returns the result of assign(std::move(e)).
+
      
+
      
+
      3. 
+
    3. 
 
      
--2- The conversion occurs as if performed by the following code fragment (using the same notation as for 
-the preceding code fragment):
+In 28.8.3 [re.regex.assign], just after p. 2 add the following new
+member definition:
 
      
-
-
      typedef num_get<charT,istreambuf_iterator<charT,traits> > numget;
-iostate err = iostate_base::goodbit;
-long lval;
-use_facet<numget>(loc).get(*this, 0, *this, err, lval);
-if (err != 0)
-  ;
-else if (lval < numeric_limits<short>::min()
-  || numeric_limits<short>::max() < lval)
-     err = ios_base::failbit;
-if (lval < numeric_limits<short>::min())
-{
-  err |= ios_base::failbit;
-  val = numeric_limits<short>::min();
-}
-else if (lval > numeric_limits<short>::max())
-{
-  err |= ios_base::failbit;
-  val = numeric_limits<short>::max();
-}
-else
-  val = static_cast<short>(lval);
-setstate(err);
-
      
-
-
    
-
-
    operator>>(int& val);
+
    basic_regex& assign(basic_regex&& rhs);
 
    
 
    
 
    
--3- The conversion occurs as if performed by the following code fragment (using the same notation as for 
-the preceding code fragment):
-
    
-
-
    typedef num_get<charT,istreambuf_iterator<charT,traits> > numget;
-iostate err = iostate_base::goodbit;
-long lval;
-use_facet<numget>(loc).get(*this, 0, *this, err, lval);
-if (err != 0)
-  ;
-else if (lval < numeric_limits<int>::min()
-  || numeric_limits<int>::max() < lval)
-     err = ios_base::failbit;
-if (lval < numeric_limits<int>::min())
-{
-  err |= ios_base::failbit;
-  val = numeric_limits<int>::min();
-}
-else if (lval > numeric_limits<int>::max())
-{
-  err |= ios_base::failbit;
-  val = numeric_limits<int>::max();
-}
-else
-  val = static_cast<int>(lval);
-setstate(err);
-
    
-
-
    
-
-
    
-
-
-
-
-
-
    
-
    701. assoc laguerre poly's
    
-
    Section: TR1 5.2.1.1 [tr.num.sf.Lnm] Status: Tentatively NAD
- Submitter: Christopher Crawford Opened: 2007-06-30  Last modified: 2009-05-23
    
-
    View all issues with Tentatively NAD status.
    
-
    Discussion:
    
-
    
-I see that the definition the associated Laguerre
-polynomials TR1 5.2.1.1 [tr.num.sf.Lnm] has been corrected since
-N1687.
-However, the draft standard only specifies ranks of integer value m,
-while the associated Laguerre polynomials are actually valid for real
-values of m > -1.  In the case of non-integer values of m, the
-definition  Ln(m) = (1/n!)exx-m (d/dx)n (e-xxm+n)
-must be used, which also holds for integer values of m.  See
-Abramowitz & Stegun, 22.11.6 for the general case, and 22.5.16-17 for
-the integer case.  In fact fractional values are most commonly used in
-physics, for example to m = +/- 1/2 to describe the harmonic
-oscillator in 1 dimension, and 1/2, 3/2, 5/2, ... in 3
-dimensions.
-
    
-
    
-If I am correct, the calculation of the more general case is no
-more difficult, and is in fact the function implemented in the GNU
-Scientific Library.  I would urge you to consider upgrading the 
-standard, either adding extra functions for real m or switching the
-current ones to double.
+Effects: Move-assigns a basic_regex instance from rhs and returns *this.
 
    
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
 
    
-We understand the issue, and have opted not to extend as recommended.
+Postconditions: flags() and mark_count() return rhs.flags()
+and rhs.mark_count(), respectively, that
+rhs had before assignment, leaving rhs
+in a valid state with an unspecified value.
 
    
 
    
-Move to NAD.
+Throws: nothing.
 
    
 
    
-
-
-
    Proposed resolution:
    
-
    
-
    
+
    
+
    • +
    -

    702. Restriction in associated Legendre functions

    -

    Section: TR1 5.2.1.2 [tr.num.sf.Plm] Status: Tentatively NAD - Submitter: Christopher Crawford Opened: 2007-06-30 Last modified: 2009-05-23

    -

    View all issues with Tentatively NAD status.

    +

    724. DefaultConstructible is not defined

    +

    Section: X [utility.arg.requirements] Status: Open + Submitter: Pablo Halpern Opened: 2007-09-12 Last modified: 2009-07-28

    +

    View other active issues in [utility.arg.requirements].

    +

    View all other issues in [utility.arg.requirements].

    +

    View all issues with Open status.

    Discussion:

    -One other small thing, in TR1 5.2.1.2 [tr.num.sf.Plm], the restriction should be -|x| <= 1, not x >= 0.

    +The DefaultConstructible requirement is referenced in +several places in the August 2007 working draft +N2369, +but is not defined anywhere. +

    [ -Batavia (2009-05): +Bellevue: ]

    +

    -The error has been corrected in the pending IS. +Walking into the default/value-initialization mess...

    -Move to NAD. +Why two lines? Because we need both expressions to be valid.

    -
    - - -

    Proposed resolution:

    +AJM not sure what the phrase "default constructed" means. This is +unfortunate, as the phrase is already used 24 times in the library!

    - - - - - -
    -

    708. Locales need to be per thread and updated for POSIX changes

    -

    Section: 22 [localization] Status: Open - Submitter: Peter Dimov Opened: 2007-07-28 Last modified: 2008-09-17

    -

    View other active issues in [localization].

    -

    View all other issues in [localization].

    -

    View all issues with Open status.

    -

    Discussion:

    -The POSIX "Extended API Set Part 4," +Example: const int would not accept first line, but will accept the second.

    -

    -http://www.opengroup.org/sib/details.tpl?id=C065 -

    -introduces extensions to the C locale mechanism that -allow multiple concurrent locales to be used in the same application -by introducing a type locale_t that is very similar to -std::locale, and a number of _l functions that make use of it. +This is an issue that must be solved by concepts, but we might need to solve it independantly first.

    -The global locale (set by setlocale) is now specified to be per- -process. If a thread does not call uselocale, the global locale is -in effect for that thread. It can install a per-thread locale by -using uselocale. +It seems that the requirements are the syntax in the proposed first +column is valid, but not clear what semantics we need.

    -There is also a nice querylocale mechanism by which one can obtain -the name (such as "de_DE") for a specific facet, even for combined -locales, with no std::locale equivalent. +A table where there is no post-condition seems odd, but appears to sum up our position best.

    -std::locale should be harmonized with the new POSIX locale_t -mechanism and provide equivalents for uselocale and querylocale. +At a minimum an object is declared and is destuctible.

    +

    +Move to open, as no-one happy to produce wording on the fly. +

    +

    [ -Kona (2007): Bill and Nick to provide wording. -]

    - - -

    [ -San Francisco: Bill and Nick still intend to provide wording, but this -is a part of the task to be addressed by the group that will look into -issue 860. +2009-07-28 Reopened by Alisdair. No longer solved by concepts. ]

    @@ -8574,154 +7693,230 @@ issue

    Proposed resolution:

    +In section X [utility.arg.requirements], before table 33, add the +following table:

    +

    Table 33: DefaultConstructible requirements

    + +
    + + + + + + + + + + +
    +

    expression

    +     		+

    post-condition

    +
    +

    T + t;
    + T()

    +     		+

    T + is default constructed.

    +
    + +
    + + + +

    Rationale:

    +

    [ +San Francisco: +]

    + +
    +We believe concepts will solve this problem +(N2774). +
    +
    -

    711. Contradiction in empty shared_ptr

    -

    Section: 20.8.13.2.5 [util.smartptr.shared.obs] Status: Open - Submitter: Peter Dimov Opened: 2007-08-24 Last modified: 2008-06-18

    -

    View all other issues in [util.smartptr.shared.obs].

    +

    726. Missing regex_replace() overloads

    +

    Section: 28.11.4 [re.alg.replace] Status: Open + Submitter: Stephan T. Lavavej Opened: 2007-09-22 Last modified: 2009-07-25

    +

    View other active issues in [re.alg.replace].

    +

    View all other issues in [re.alg.replace].

    View all issues with Open status.

    Discussion:

    -A discussion on -comp.std.c++ -has identified a contradiction in the shared_ptr specification. -The note: +Two overloads of regex_replace() are currently provided:

    -

    -[ Note: this constructor allows creation of an empty shared_ptr instance with a non-NULL stored pointer. --end note ] -

    +
    template <class OutputIterator, class BidirectionalIterator, 
+    class traits, class charT> 
+  OutputIterator 
+  regex_replace(OutputIterator out, 
+                BidirectionalIterator first, BidirectionalIterator last, 
+                const basic_regex<charT, traits>& e, 
+                const basic_string<charT>& fmt, 
+                regex_constants::match_flag_type flags = 
+                  regex_constants::match_default);
+ 
+template <class traits, class charT> 
+  basic_string<charT> 
+  regex_replace(const basic_string<charT>& s, 
+                const basic_regex<charT, traits>& e, 
+                const basic_string<charT>& fmt, 
+                regex_constants::match_flag_type flags = 
+                  regex_constants::match_default);
+
    -

    -after the aliasing constructor -

    +
      +
    1. Overloads taking const charT * are provided for regex_match() and +regex_search(), but not regex_replace(). This is inconsistent.
      2. +
    2. +

      The absence of const charT * overloads prevents ordinary-looking code from compiling, such as:

      -
      template<class Y> shared_ptr(shared_ptr<Y> const& r, T *p);
+
      const string s("kitten");
+const regex r("en");
+cout << regex_replace(s, r, "y") << endl;
 
      
 
 
      
-reflects the intent of
-N2351
-to, well, allow the creation of an empty shared_ptr
-with a non-NULL stored pointer.
+The compiler error message will be something like "could not deduce
+template argument for 'const std::basic_string<_Elem> &' from 'const
+char[1]'".
+
      
+
+
      
+Users expect that anything taking a basic_string<charT> can also take a
+const charT *.  In their own code, when they write a function taking
+std::string (or std::wstring), they can pass a const char * (or const
+wchar_t *), thanks to basic_string's implicit constructor.  Because the
+regex algorithms are templated on charT, they can't rely on
+basic_string's implicit constructor (as the compiler error message
+indicates, template argument deduction fails first).
 
      
 
 
      
-This is contradicted by the second sentence in the Returns clause of 20.8.13.2.5 [util.smartptr.shared.obs]:
+If a user figures out what the compiler error message means, workarounds
+are available - but they are all verbose.  Explicit template arguments
+could be given to regex_replace(), allowing basic_string's implicit
+constructor to be invoked - but charT is the last template argument, not
+the first, so this would be extremely verbose.  Therefore, constructing
+a basic_string from each C string is the simplest workaround.
 
      
+
      3. + +
    3. +There is an efficiency consideration: constructing basic_strings can +impose performance costs that could be avoided by a library +implementation taking C strings and dealing with them directly. +(Currently, for replacement sources, C strings can be converted into +iterator pairs at the cost of verbosity, but for format strings, there +is no way to avoid constructing a basic_string.) +
      4. +
    + +

    [ +Sophia Antipolis: +]

    +
    -
    T* get() const;
-
    -

    -Returns: the stored pointer. Returns a null pointer if *this is empty. -

    +We note that Boost already has these overloads. However, the proposed +wording is provided only for 28.11.4 [re.alg.replace]; wording is needed for the synopsis +as well. We also note that this has impact on match_results::format, +which may require further overloads.

    [ -Bellevue: +2009-07 Frankfurt: ]

    -

    -Adopt option 1 and move to review, not ready. -

    -

    -There was a lot of confusion about what an empty shared_ptr is (the term -isn't defined anywhere), and whether we have a good mental model for how -one behaves. We think it might be possible to deduce what the definition -should be, but the words just aren't there. We need to open an issue on -the use of this undefined term. (The resolution of that issue might -affect the resolution of issue 711.) -

    -

    -The LWG is getting more uncomfortable with the aliasing proposal (N2351) -now that we realize some of its implications, and we need to keep an eye -on it, but there isn't support for removing this feature at this time. -

    +Daniel to tweak for us.

    [ -Sophia Antipolis: +2009-07-25 Daniel tweaks both this issue and 727. ]

    -We heard from Peter Dimov, who explained his reason for preferring solution 1. +This is solved by the proposed resolution of 727.

    +
    + + + +

    Proposed resolution:

    +

    -Because it doesn't seem to add anything. It simply makes the behavior -for p = 0 undefined. For programmers who don't create empty pointers -with p = 0, there is no difference. Those who do insist on creating them -presumably have a good reason, and it costs nothing for us to define the -behavior in this case. -

    -

    -The aliasing constructor is sharp enough as it is, so "protecting" users -doesn't make much sense in this particular case. -

    -

    -> Do you have a use case for r being empty and r being non-null? -

    -

    -I have received a few requests for it from "performance-conscious" -people (you should be familiar with this mindset) who don't like the -overhead of allocating and maintaining a control block when a null -deleter is used to approximate a raw pointer. It is obviously an "at -your own risk", low-level feature; essentially a raw pointer behind a -shared_ptr facade. -

    -

    -We could not agree upon a resolution to the issue; some of us thought -that Peter's description above is supporting an undesirable behavior. -

    - - - - -

    Proposed resolution:

    -

    -In keeping the N2351 spirit and obviously my preference, change 20.8.13.2.5 [util.smartptr.shared.obs]: +Provide additional overloads for regex_replace(): one additional +overload of the iterator-based form (taking const charT* fmt), and three +additional overloads of the convenience form (one taking const charT* +str, another taking const charT* fmt, and the third taking both const +charT* str and const charT* fmt). 28.11.4 [re.alg.replace]:

    -
    T* get() const;
+
    template <class OutputIterator, class BidirectionalIterator, 
+    class traits, class charT> 
+  OutputIterator 
+  regex_replace(OutputIterator out, 
+                BidirectionalIterator first, BidirectionalIterator last, 
+                const basic_regex<charT, traits>& e, 
+                const basic_string<charT>& fmt, 
+                regex_constants::match_flag_type flags = 
+                  regex_constants::match_default);
+
+template <class OutputIterator, class BidirectionalIterator, 
+    class traits, class charT> 
+  OutputIterator 
+  regex_replace(OutputIterator out, 
+                BidirectionalIterator first, BidirectionalIterator last, 
+                const basic_regex<charT, traits>& e, 
+                const charT* fmt, 
+                regex_constants::match_flag_type flags = 
+                  regex_constants::match_default);
 
    
-
    
-Returns: the stored pointer. Returns a null pointer if *this is empty.
-
    
-
    +

    ...

    +
    template <class traits, class charT> 
+  basic_string<charT> 
+  regex_replace(const basic_string<charT>& s, 
+                const basic_regex<charT, traits>& e, 
+                const basic_string<charT>& fmt, 
+                regex_constants::match_flag_type flags = 
+                  regex_constants::match_default);
 
-
    
-Alternative proposed resolution: (I won't be happy if we do this, but it's possible):
-
    
+template <class traits, class charT> 
+  basic_string<charT> 
+  regex_replace(const basic_string<charT>& s, 
+                const basic_regex<charT, traits>& e, 
+                const charT* fmt, 
+                regex_constants::match_flag_type flags = 
+                  regex_constants::match_default);
 
-
    
-Change 20.8.13.2.1 [util.smartptr.shared.const]:
-
    
+template <class traits, class charT> 
+  basic_string<charT> 
+  regex_replace(const charT* s, 
+                const basic_regex<charT, traits>& e, 
+                const basic_string<charT>& fmt, 
+                regex_constants::match_flag_type flags = 
+                  regex_constants::match_default);
 
-
    
-
    template<class Y> shared_ptr(shared_ptr<Y> const& r, T *p);
+template <class traits, class charT> 
+  basic_string<charT> 
+  regex_replace(const charT* s, 
+                const basic_regex<charT, traits>& e, 
+                const charT* fmt, 
+                regex_constants::match_flag_type flags = 
+                  regex_constants::match_default);
 
    
-
    
-
    
-Requires: If r is empty, p shall be 0.
-
    
-
    
-[ Note: this constructor allows creation of an empty shared_ptr
-instance with a non-NULL stored pointer. 
--- end note ]
-
    
-
    
 
    
 
 
@@ -8730,33 +7925,28 @@ instance with a non-NULL stored pointer.
 
 
 
    
-
    716. Production in [re.grammar] not actually modified
    
-
    Section: 28.14 [re.grammar] Status: Open
- Submitter: Stephan T. Lavavej Opened: 2007-08-31  Last modified: 2009-05-23
    
+
    727. regex_replace() doesn't accept basic_strings with custom traits and allocators
    
+
    Section: 28.11.4 [re.alg.replace] Status: Open
+ Submitter: Stephan T. Lavavej Opened: 2007-09-22  Last modified: 2009-07-31
    
+
    View other active issues in [re.alg.replace].
    
+
    View all other issues in [re.alg.replace].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-TR1 7.13 [tr.re.grammar]/3 and C++0x WP 28.14 [re.grammar]/3 say:
-
    
-
-
    
-
    
-The following productions within the ECMAScript grammar are modified as follows:
-
    
-
-
    CharacterClass ::
-[ [lookahead ∉ {^}] ClassRanges ]
-[ ^ ClassRanges ]
-
    
-
-
    
-
-
    
-This definition for CharacterClass appears to be exactly identical to that in ECMA-262.
+regex_match() and regex_search() take const basic_string<charT, ST,
+SA>&.  regex_replace() takes const basic_string<charT>&.  This prevents
+regex_replace() from accepting basic_strings with custom traits and
+allocators.
 
    
 
 
    
-Was an actual modification intended here and accidentally omitted, or was this production accidentally included?
+Overloads of regex_replace() taking basic_string should be additionally
+templated on class ST, class SA and take const basic_string<charT, ST,
+SA>&.  Consistency with regex_match() and regex_search() would place
+class ST, class SA as the first template arguments; compatibility with
+existing code using TR1 and giving explicit template arguments to
+regex_replace() would place class ST, class SA as the last template
+arguments.
 
    
 
 
    [
@@ -8765,1071 +7955,1289 @@ Batavia (2009-05):
 
 
    
 
    
-We agree that what is specified is identical to what ECMA-262 specifies.
-Pete would like to take a bit of time to assess whether we had intended,
-but failed, to make a change.
-It would also be useful to hear from John Maddock on the issue.
+Bill comments, "We need to look at the depth of this change."
 
    
 
    
-Move to Open.
+Pete remarks that we are here dealing with a convenience function
+that saves a user from calling the iterato-based overload.
 
    
-
    
-
-
-
    Proposed resolution:
    
 
    
-Remove this mention of the CharacterClass production.
+Move to Open.
 
    
+
 
-
    CharacterClass ::
-[ [lookahead ∉ {^}] ClassRanges ]
-[ ^ ClassRanges ]
-
    
+
    [
+2009-07 Frankfurt:
+]
    
 
 
+
    
+Howard to ask Stephan Lavavej to provide wording.
+
    
 
+
    [
+2009-07-17 Stephan provided wording.
+]
    
 
 
+
    [
+2009-07-25 Daniel tweaks both this issue and 726.
+]
    
 
-
    
-
    718. basic_string is not a sequence
    
-
    Section: 21.4 [basic.string] Status: Open
- Submitter: Bo Persson Opened: 2007-08-18  Last modified: 2008-03-12
    
-
    View other active issues in [basic.string].
    
-
    View all other issues in [basic.string].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    
-Paragraph 21.4 [basic.string]/3 states:
-
    
 
 
    
 
    
-The class template basic_string conforms to the requirements for a 
-Sequence (23.1.1) and for a Reversible Container (23.1).
+One relevant part of the proposed resolution below suggests
+to add a new overload of the format member function in the
+match_results class template that accepts two character pointers
+defining the begin and end of a format range. A more general
+approach could have proposed a pair of iterators instead, but
+the used pair of char pointers reflects existing practice. If the
+committee strongly favors an iterator-based signature, this
+could be simply changed. I think that the minimum requirement
+should be a BidirectionalIterator, but current implementations
+take advantage (at least partially) of the RandomAccessIterator
+sub interface of the char pointers.
 
    
-
    
 
-
    
-First of all, 23.2.3 [sequence.reqmts] is no longer "Sequence" but "Sequence container". 
-Secondly, after the resent changes to containers (emplace, push_back, 
-const_iterator parameters to insert and erase), basic_string is not 
-even close to conform to the current requirements.
-
    
+
    Suggested Resolution:
    
+
+
    [Moved into the proposed resloution]
    
 
-
    [
-Bellevue:
-]
    
 
 
-
    
-
      
-
    • emplace, for example, may not make sense for strings. Is also likely suboptimal
      • 
-
    • with concepts do we need to maintain string as sequence container?
      • 
-
    • One approach might be to say something like: string is a sequence except it doesn't have these functions
      • 
-
    
-
      
-
    • basic_string already has push_back
      • 
-
    • const_iterator parameters to insert and erase should be added to basic_string
      • 
-
    • this leaves emplace to handle -- we have the following options:
-
        
-
      • option 1: add it to string even though it's optional
        • 
-
      • option 2: make emplace optional to sequences (move from table 89 to 90)
        • 
-
      • option 3: say string not sequence (the proposal),
        • 
-
      • option 4: add an exception to basic string wording.
        • 
-
      
-
      • 
-
    
-General consensus is to suggest option 2.
 
    
 
+
    [
+2009-07-30 Stephan agrees with Daniel's wording.  Howard places Daniel's wording
+in the Proposed Resolution.
+]
    
+
+
 
 
 
    Proposed resolution:
    
+
+
      
+
    1. 
 
      
-Remove this sentence, in recognition of the fact that basic_string is 
-not just a vector-light for literal types, but something quite 
-different, a string abstraction in its own right.
+Change 28.4 [re.syn] as indicated:
 
      
 
+
      // 28.11.4, function template regex_replace:
+template <class OutputIterator, class BidirectionalIterator,
+          class traits, class charT, class ST, class SA>
+  OutputIterator
+  regex_replace(OutputIterator out,
+                BidirectionalIterator first, BidirectionalIterator last,
+                const basic_regex<charT, traits>& e,
+                const basic_string<charT, ST, SA>& fmt,
+                regex_constants::match_flag_type flags =
+                  regex_constants::match_default);
 
+
+template <class OutputIterator, class BidirectionalIterator,
+          class traits, class charT>
+  OutputIterator
+  regex_replace(OutputIterator out,
+                BidirectionalIterator first, BidirectionalIterator last,
+                const basic_regex<charT, traits>& e,
+                const charT* fmt,
+                regex_constants::match_flag_type flags =
+                  regex_constants::match_default);
+
 
+template <class traits, class charT, class ST, class SA,
+          class FST, class FSA>
+  basic_string<charT, ST, SA>
+  regex_replace(const basic_string<charT, ST, SA>& s,
+                const basic_regex<charT, traits>& e,
+                const basic_string<charT, FST, FSA>& fmt,
+                regex_constants::match_flag_type flags =
+                  regex_constants::match_default);
 
+
+template <class traits, class charT, class ST, class SA>
+  basic_string<charT, ST, SA>
+  regex_replace(const basic_string<charT, ST, SA>& s,
+                const basic_regex<charT, traits>& e,
+                const charT* fmt,
+                regex_constants::match_flag_type flags =
+                  regex_constants::match_default);
+
 
-
      
-
      719. std::is_literal type traits should be provided
      
-
      Section: 20.6 [meta] Status: Open
- Submitter: Daniel Krügler Opened: 2007-08-25  Last modified: 2009-03-14
      
-
      View other active issues in [meta].
      
-
      View all other issues in [meta].
      
-
      View all issues with Open status.
      
-
      Discussion:
      
-
      
-Since the inclusion of constexpr in the standard draft N2369 we have
-a new type category "literal", which is defined in 3.9 [basic.types]/p.11:
-
      
+
+template <class traits, class charT, class ST, class SA>
+  basic_string<charT>
+  regex_replace(const charT* s,
+                const basic_regex<charT, traits>& e,
+                const basic_string<charT, ST, SA>& fmt,
+                regex_constants::match_flag_type flags =
+                  regex_constants::match_default);
+
 
-
      
-
      
--11- A type is a literal type if it is:
-
      
-
        
-
      • a scalar type; or
        • 
-
      • a class type (clause 9) with
        
-
          
-
        • a trivial copy constructor,
          • 
-
        • a trivial destructor,
          • 
-
        • at least one constexpr constructor other than the copy constructor,
          • 
-
        • no virtual base classes, and
          • 
-
        • all non-static data members and base classes of literal types; or
          • 
-
        
+
+template <class traits, class charT>
+  basic_string<charT>
+  regex_replace(const charT* s,
+                const basic_regex<charT, traits>& e,
+                const charT* fmt,
+                regex_constants::match_flag_type flags =
+                  regex_constants::match_default);
+
+
      
 
      2. 
-
    2. an array of literal type.
      3. 
-
-
 
+
    3. 
 
      
-I strongly suggest that the standard provides a type traits for
-literal types in 20.6.4.3 [meta.unary.prop] for several reasons:
+Change 28.10 [re.results]/3, class template match_results as
+indicated:
 
      
 
-
        
-
      1. To keep the traits in sync with existing types.
        2. 
-
      2. I see many reasons for programmers to use this trait in template
-   code to provide optimized template definitions for these types,
-   see below.
        3. 
-
      3. A user-provided definition of this trait is practically impossible
-to write portably.
        4. 
-
      
+
      
+template <class OutputIter>
+  OutputIter
+  format(OutputIter out,
+         const char_type* fmt_first, const char_type* fmt_last,
+         regex_constants::match_flag_type flags =
+           regex_constants::format_default) const;
+
+
+template <class OutputIter, class ST, class SA>
+  OutputIter
+  format(OutputIter out,
+         const string_typebasic_string<char_type, ST, SA>& fmt,
+         regex_constants::match_flag_type flags =
+           regex_constants::format_default) const;
+
+template <class ST, class SA>
+  string_typebasic_string<char_type, ST, SA>
+  format(const string_typebasic_string<char_type, ST, SA>& fmt,
+         regex_constants::match_flag_type flags =
+           regex_constants::format_default) const;
+
+
+string_type
+format(const char_type* fmt,
+       regex_constants::match_flag_type flags =
+         regex_constants::format_default) const;
+
+
      
+
      4. 
 
+
    4. 
 
      
-The special problem of reason (c) is that I don't see currently a
-way to portably test the condition for literal class types:
+Insert at the very beginning of 28.10.4 [re.results.form] the following:
 
      
 
+
      
+template <class OutputIter>
+  OutputIter
+  format(OutputIter out,
+         const char_type* fmt_first, const char_type* fmt_last,
+         regex_constants::match_flag_type flags =
+           regex_constants::format_default) const;
+
+
      
 
      
-
        
-
      • at least one constexpr constructor other than the copy constructor,
        • 
-
      
-
      
-
-
-
-
      [
-Alisdair is considering preparing a paper listing a number of missing
-type traits, and feels that it might be useful to handle them all
-together rather than piecemeal. This would affect issue 719 and 750.
-These two issues should move to OPEN pending AM paper on type traits.
-]
      
 
+
      
+1 Requires: The type OutputIter shall satisfy the requirements for an
+Output Iterator (24.2.3 [output.iterators]).
+
      
 
+
      
+2 Effects: Copies the character sequence [fmt_first,fmt_last) to
+OutputIter out. Replaces each
+format specifier or escape sequence in the copied range with either
+the character(s) it represents
+or the sequence of characters within *this to which it refers. The
+bitmasks specified in flags
+determines what format specifiers and escape sequences are recognized.
+
      
 
+
      
+3 Returns: out.
+
      
+
      
+
+
      5. 
 
-
      Proposed resolution:
      
+
    5. 
 
      
-In 20.6.2 [meta.type.synop] in the group "type properties",
-just below the line
+Change 28.10.4 [re.results.form], before p. 1 until p. 3 (according to
+previous numbering)
+as indicated:
 
      
 
-
      template <class T> struct is_pod;
-
      
+
      template <class OutputIter, class ST, class SA>
+  OutputIter
+  format(OutputIter out,
+         const string_typebasic_string<char_type, ST, SA>& fmt,
+         regex_constants::match_flag_type flags =
+           regex_constants::format_default) const;
+
      
 
+
      
 
      
-add a new one:
+Requires: The type OutputIter shall satisfy the requirements for
+an Output Iterator (24.2.3).
 
      
 
-
      template <class T> struct is_literal;
-
      
+
      
+Effects: Copies the character sequence [fmt.begin(),fmt.end()) to
+OutputIter out. Replaces each
+format specifier or escape sequence in fmt with either the
+character(s) it represents or the sequence of
+characters within *this to which it refers. The bitmasks specified in
+flags determines what format
+specifiers and escape sequences are recognized.
+
      
 
 
      
-In 20.6.4.3 [meta.unary.prop], table Type Property Predicates, just
-below the line for the is_pod property add a new line:
+Returns: outformat(out, fmt.data(), fmt.data() +
+fmt.size(), flags).
 
      
+
      
+
      
+
      6. 
 
-
-
-
-
-
-
-
-
-
-
      TemplateConditionPreconditions
      template <class T> struct is_literal;T is a literal type (3.9)T shall be a complete type, an
-array of unknown bound, or
-(possibly cv-qualified) void.
      
+
    6. 
+
      
+Change 28.10.4 [re.results.form], before p. 4 until p. 4 (according to
+previous numbering) as indicated:
+
      
 
+
      template <class ST, class SA>
+  string_typebasic_string<char_type, ST, SA>
+  format(const string_typebasic_string<char_type, ST, SA>& fmt,
+         regex_constants::match_flag_type flags =
+           regex_constants::format_default) const;
+
      
 
+
      
+
      
+Effects: Returns a copy of the string fmt. Replaces each format
+specifier or escape sequence
+in fmt with either the character(s) it represents or the sequence of
+characters within *this to which
+it refers. The bitmasks specified in flags determines what format
+specifiers and escape sequences are
+recognized. Constructs an empty string result of type
+basic_string<char_type, ST, SA>,
+and calls format(back_inserter(result), fmt, flags).
+
      
 
+
      
+Returns: result
+
      
+
      
+
      
+
      7. 
 
+
    7. 
+
      
+At the end of 28.10.4 [re.results.form] insert as indicated:
+
      
 
+
      
+string_type
+  format(const char_type* fmt,
+         regex_constants::match_flag_type flags =
+           regex_constants::format_default) const;
+
      
 
-
      
-
      721. wstring_convert inconsistensies
      
-
      Section: 22.3.3.2.2 [conversions.string] Status: Open
- Submitter: Bo Persson Opened: 2007-08-27  Last modified: 2008-09-18
      
-
      View other active issues in [conversions.string].
      
-
      View all other issues in [conversions.string].
      
-
      View all issues with Open status.
      
-
      Discussion:
      
+
      
 
      
-Paragraph 3 says that the Codecvt template parameter shall meet the 
-requirements of std::codecvt, even though std::codecvt itself cannot 
-be used (because of a protected destructor).
+Effects: Constructs an empty string result of type string_type, and calls
+format(back_inserter(result), fmt, fmt +
+char_traits<char_type>::length(fmt), flags).
 
      
-
 
      
-How are we going to explain this code to beginning programmers?
+Returns: result
 
      
+
      
+
      
 
-
      template<class I, class E, class S>
-struct codecvt : std::codecvt<I, E, S>
-{
-    ~codecvt()
-    { }
-};
+
      8. 
 
-void main()
-{
-    std::wstring_convert<codecvt<wchar_t, char, std::mbstate_t> > compiles_ok;
-    
-    std::wstring_convert<std::codecvt<wchar_t, char, std::mbstate_t> >   not_ok;
-}
-
    +
  • +

    +Change 28.11.4 [re.alg.replace] before p. 1 as indicated: +

    -

    [ -San Francisco: -]

    +
    template <class OutputIterator, class BidirectionalIterator,
+          class traits, class charT, class ST, class SA>
+  OutputIterator
+  regex_replace(OutputIterator out,
+                BidirectionalIterator first, BidirectionalIterator last,
+                const basic_regex<charT, traits>& e,
+                const basic_string<charT, ST, SA>& fmt,
+                regex_constants::match_flag_type flags =
+                  regex_constants::match_default);
 
+
+template <class OutputIterator, class BidirectionalIterator,
+          class traits, class charT>
+  OutputIterator
+  regex_replace(OutputIterator out,
+                BidirectionalIterator first, BidirectionalIterator last,
+                const basic_regex<charT, traits>& e,
+                const charT* fmt,
+                regex_constants::match_flag_type flags =
+                  regex_constants::match_default);
+
    -Bill will propose a resolution. +Effects: [..]. If any matches are found then, for each such match, if !(flags & + regex_constants::format_no_copy) calls std::copy(m.prefix().first, +m.prefix().second, + out), and then calls m.format(out, fmt, flags) for the first +form of the function + and m.format(out, fmt, fmt + char_traits<charT>::length(fmt), flags) +for the second + form. [..].
    +
    +
    • - -

    Proposed resolution:

    +

  • +Change 28.11.4 [re.alg.replace] before p. 3 as indicated:

    +
    template <class traits, class charT, class ST, class SA,
+          class FST, class FSA>
+  basic_string<charT, ST, SA>
+  regex_replace(const basic_string<charT, ST, SA>& s,
+                const basic_regex<charT, traits>& e,
+                const basic_string<charT, FST, FSA>& fmt,
+                regex_constants::match_flag_type flags =
+                  regex_constants::match_default);
 
+
+template <class traits, class charT, class ST, class SA>
+  basic_string<charT, ST, SA>
+  regex_replace(const basic_string<charT, ST, SA>& s,
+                const basic_regex<charT, traits>& e,
+                const charT* fmt,
+                regex_constants::match_flag_type flags =
+                  regex_constants::match_default);
+
    +
    +Effects: Constructs an empty string result of type basic_string<charT, +ST, SA>, calls regex_replace(back_inserter(result), s.begin(), s.end(), +e, fmt, flags), and then returns result. +
    +
    +
    • - -
    -

    723. basic_regex should be moveable

    -

    Section: 28.9 [re.regex] Status: Open - Submitter: Daniel Krügler Opened: 2007-08-29 Last modified: 2009-03-13

    -

    View all other issues in [re.regex].

    -

    View all issues with Open status.

    -

    Discussion:

    - -

    Addresses UK 316

    - +

  • -According to the current state of the standard draft, the class -template basic_regex, as described in 28.9 [re.regex]/3, is -neither MoveConstructible nor MoveAssignable. -IMO it should be, because typical regex state machines tend -to have a rather large data quantum and I have seen several -use cases, where a factory function returns regex values, -which would take advantage of moveabilities. +At the end of 28.11.4 [re.alg.replace] add the following new prototype description:

    -

    [ -Sophia Antipolis: -]

    +
    
+template <class traits, class charT, class ST, class SA>
+  basic_string<charT>
+  regex_replace(const charT* s,
+                const basic_regex<charT, traits>& e,
+                const basic_string<charT, ST, SA>& fmt,
+                regex_constants::match_flag_type flags =
+                  regex_constants::match_default);
+
 
+
+template <class traits, class charT>
+  basic_string<charT>
+  regex_replace(const charT* s,
+                const basic_regex<charT, traits>& e,
+                const charT* fmt,
+                regex_constants::match_flag_type flags =
+                  regex_constants::match_default);
+
    -Needs wording for the semantics, the idea is agreed upon. + +Effects: Constructs an empty string result of type basic_string<charT>, +calls regex_replace(back_inserter(result), s, s + +char_traits<charT>::length(s), +e, fmt, flags), and then returns result. +
    +
    +
    • -

    [ -Post Summit Daniel updated wording to reflect new "swap rules". -]

    + -

    Proposed resolution:

    -

    -In the class definition of basic_regex, just below 28.9 [re.regex]/3, -perform the following changes: -

    -
      -
    1. + + + +
      +

      742. Enabling swap for proxy iterators

      +

      Section: X [utility.arg.requirements] Status: Open + Submitter: Howard Hinnant Opened: 2007-10-10 Last modified: 2009-07-28

      +

      View other active issues in [utility.arg.requirements].

      +

      View all other issues in [utility.arg.requirements].

      +

      View all issues with Open status.

      +

      Discussion:

      -Just after basic_regex(const basic_regex&); insert: +This issue was split from 672. 672 now just +deals with changing the requirements of T in the Swappable +requirement from CopyConstructible and CopyAssignable to +MoveConstructible and MoveAssignable.

      -
      basic_regex(basic_regex&&);
-
      -
      2. -

    2. -Just after basic_regex& operator=(const basic_regex&); insert: +This issue seeks to widen the Swappable requirement to support proxy iterators. Here +is example code:

      -
      basic_regex& operator=(basic_regex&&);
+
+
      namespace Mine {
+
+template <class T>
+struct proxy {...};
+
+template <class T>
+struct proxied_iterator
+{
+   typedef T value_type;
+   typedef proxy<T> reference;
+   reference operator*() const;
+   ...
+};
+
+struct A
+{
+   // heavy type, has an optimized swap, maybe isn't even copyable or movable, just swappable
+   void swap(A&);
+   ...
+};
+
+void swap(A&, A&);
+void swap(proxy<A>, A&);
+void swap(A&, proxy<A>);
+void swap(proxy<A>, proxy<A>);
+
+}  // Mine
+
+...
+
+Mine::proxied_iterator<Mine::A> i(...)
+Mine::A a;
+swap(*i1, a);
 
      
-
      3. -
    3. +

      -Just after basic_regex& assign(const basic_regex& that); insert: +The key point to note in the above code is that in the call to swap, *i1 +and a are different types (currently types can only be Swappable with the +same type). A secondary point is that to support proxies, one must be able to pass rvalues +to swap. But note that I am not stating that the general purpose std::swap +should accept rvalues! Only that overloaded swaps, as in the example above, be allowed +to take rvalues.

      -
      basic_regex& assign(basic_regex&& that);
-
      -
      4. -
    4. +

      -In 28.9.2 [re.regex.construct], just after p.11 add the following -new member definition: +That is, no standard library code needs to change. We simply need to have a more flexible +definition of Swappable.

      -
      basic_regex(basic_regex&& e);
-
      + +

      [ +Bellevue: +]

      + +

      -Effects: Move-constructs a basic_regex instance from e. +While we believe Concepts work will define a swappable concept, we +should still resolve this issue if possible to give guidance to the +Concepts work.

      -Postconditions: flags() and mark_count() return e.flags() and -e.mark_count(), respectively, -that e had before construction, leaving -e in a valid state with an unspecified value. +Would an ambiguous swap function in two namespaces found by ADL break +this wording? Suggest that the phrase "valid expression" means such a +pair of types would still not be swappable.

      -Throws: nothing. +Motivation is proxy-iterators, but facility is considerably more +general. Are we happy going so far?

      -
      -
      -
      5. -

    5. -Also in 28.9.2 [re.regex.construct], just after p.18 add the -following new member definition: +We think this wording is probably correct and probably an improvement on +what's there in the WP. On the other hand, what's already there in the +WP is awfully complicated. Why do we need the two bullet points? They're +too implementation-centric. They don't add anything to the semantics of +what swap() means, which is there in the post-condition. What's wrong +with saying that types are swappable if you can call swap() and it +satisfies the semantics of swapping?

      - -
      basic_regex& operator=(basic_regex&& e);
-
      -
      -Effects: Returns the result of assign(std::move(e)). -
      -
      6. -
    6. + +

      [ +2009-07-28 Reopened by Alisdair. No longer solved by concepts. +]

      + + + + +

      Proposed resolution:

      -In 28.9.3 [re.regex.assign], just after p. 2 add the following new -member definition: +Change X [utility.arg.requirements]:

      -
      basic_regex& assign(basic_regex&& rhs);
-
      +
      +

      -Effects: Move-assigns a basic_regex instance from rhs and returns *this. -

      -

      -Postconditions: flags() and mark_count() return rhs.flags() -and rhs.mark_count(), respectively, that -rhs had before assignment, leaving rhs -in a valid state with an unspecified value. +-1- The template definitions in the C++ Standard Library refer to various +named requirements whose details are set out in tables 31-38. In these +tables, T and V are is a types to be supplied by a C++ program +instantiating a template; a, b, and c are +values of type const T; s and t are modifiable +lvalues of type T; u is a value of type (possibly +const) T; and rv is a non-const +rvalue of type T; w is a value of type T; and v is a value of type V.

      + + + + + + + +
      Table 37: Swappable requirements [swappable]
      expressionreturn typepost-condition
      swap(sw,tv)voidtw has the value originally +held by uv, and +uv has the value originally held +by tw

      -Throws: nothing. +The Swappable requirement is met by satisfying one or more of the following conditions:

      +
        +
      • +T is Swappable if T and V are +the same type and T satisfies the +CopyConstructible +MoveConstructible requirements (Table 34 +33) and the CopyAssignable +MoveAssignable requirements (Table 36 +35); +
        • +
      • +T is Swappable with V if a namespace scope function named +swap exists in the same namespace as the definition of +T or V, such that the expression +swap(tw,u v) is valid and has the +semantics described in this table. +
        • +
      +
      + + + +

      Rationale:

      +

      [ +post San Francisco: +]

      + + +
      +Solved by +N2758.
      -
      7. -
    +
    -

    726. Missing regex_replace() overloads

    -

    Section: 28.12.4 [re.alg.replace] Status: Open - Submitter: Stephan T. Lavavej Opened: 2007-09-22 Last modified: 2008-06-18

    -

    View other active issues in [re.alg.replace].

    -

    View all other issues in [re.alg.replace].

    +

    774. Member swap undefined for most containers

    +

    Section: 23 [containers] Status: Open + Submitter: Alisdair Meredith Opened: 2008-01-14 Last modified: 2009-07-30

    +

    View other active issues in [containers].

    +

    View all other issues in [containers].

    View all issues with Open status.

    Discussion:

    -Two overloads of regex_replace() are currently provided: +It appears most containers declare but do not define a member-swap +function.

    -
    template <class OutputIterator, class BidirectionalIterator, 
-    class traits, class charT> 
-  OutputIterator 
-  regex_replace(OutputIterator out, 
-                BidirectionalIterator first, BidirectionalIterator last, 
-                const basic_regex<charT, traits>& e, 
-                const basic_string<charT>& fmt, 
-                regex_constants::match_flag_type flags = 
-                  regex_constants::match_default);
- 
-template <class traits, class charT> 
-  basic_string<charT> 
-  regex_replace(const basic_string<charT>& s, 
-                const basic_regex<charT, traits>& e, 
-                const basic_string<charT>& fmt, 
-                regex_constants::match_flag_type flags = 
-                  regex_constants::match_default);
-
    - -
      -
    1. Overloads taking const charT * are provided for regex_match() and -regex_search(), but not regex_replace(). This is inconsistent.
      2. -
    2. -

      The absence of const charT * overloads prevents ordinary-looking code from compiling, such as:

      - -
      const string s("kitten");
-const regex r("en");
-cout << regex_replace(s, r, "y") << endl;
-
      -

      -The compiler error message will be something like "could not deduce -template argument for 'const std::basic_string<_Elem> &' from 'const -char[1]'". +This is unfortunate, as all overload the swap algorithm to call the +member-swap function! +(required for swappable guarantees [Table 37] and Container Requirements +[Table 87])

      -Users expect that anything taking a basic_string<charT> can also take a -const charT *. In their own code, when they write a function taking -std::string (or std::wstring), they can pass a const char * (or const -wchar_t *), thanks to basic_string's implicit constructor. Because the -regex algorithms are templated on charT, they can't rely on -basic_string's implicit constructor (as the compiler error message -indicates, template argument deduction fails first). +Note in particular that Table 87 gives semantics of a.swap(b) as swap(a,b), +yet for all containers we define swap(a,b) to call a.swap(b) - a circular +definition.

      -If a user figures out what the compiler error message means, workarounds -are available - but they are all verbose. Explicit template arguments -could be given to regex_replace(), allowing basic_string's implicit -constructor to be invoked - but charT is the last template argument, not -the first, so this would be extremely verbose. Therefore, constructing -a basic_string from each C string is the simplest workaround. +A quick survey of clause 23 shows that the following containers provide a +definition for member-swap:

      -
      3. -
    3. -There is an efficiency consideration: constructing basic_strings can -impose performance costs that could be avoided by a library -implementation taking C strings and dealing with them directly. -(Currently, for replacement sources, C strings can be converted into -iterator pairs at the cost of verbosity, but for format strings, there -is no way to avoid constructing a basic_string.) -
      4. -
    +
    array
+queue
+stack
+vector
+
    -

    [ -Sophia Antipolis: -]

    +

    +Whereas the following declare it, but do not define the semantics: +

    +
    deque
+list
+map
+multimap
+multiset
+priority_queue
+set
+unordered_map
+unordered_multi_map
+unordered_multi_set
+unordered_set
+
    +

    +Suggested resolution: +

    -We note that Boost already has these overloads. However, the proposed -wording is provided only for 28.12.4 [re.alg.replace]; wording is needed for the synopsis -as well. We also note that this has impact on match_results::format, -which may require further overloads. +Provide a definition for each of the affected containers...
    +

    [ +Bellevue: +]

    -

    Proposed resolution:

    -

    -Provide additional overloads for regex_replace(): one additional -overload of the iterator-based form (taking const charT* fmt), and three -additional overloads of the convenience form (one taking const charT* -str, another taking const charT* fmt, and the third taking both const -charT* str and const charT* fmt). 28.12.4 [re.alg.replace]: -

    -
    -
    template <class OutputIterator, class BidirectionalIterator, 
-    class traits, class charT> 
-  OutputIterator 
-  regex_replace(OutputIterator out, 
-                BidirectionalIterator first, BidirectionalIterator last, 
-                const basic_regex<charT, traits>& e, 
-                const basic_string<charT>& fmt, 
-                regex_constants::match_flag_type flags = 
-                  regex_constants::match_default);
-
-template <class OutputIterator, class BidirectionalIterator, 
-    class traits, class charT> 
-  OutputIterator 
-  regex_replace(OutputIterator out, 
-                BidirectionalIterator first, BidirectionalIterator last, 
-                const basic_regex<charT, traits>& e, 
-                const charT* fmt, 
-                regex_constants::match_flag_type flags = 
-                  regex_constants::match_default);
-
    -

    ...

    -
    template <class traits, class charT> 
-  basic_string<charT> 
-  regex_replace(const basic_string<charT>& s, 
-                const basic_regex<charT, traits>& e, 
-                const basic_string<charT>& fmt, 
-                regex_constants::match_flag_type flags = 
-                  regex_constants::match_default);
+Move to Open and ask Alisdair to provide wording.
+
    -template <class traits, class charT> - basic_string<charT> - regex_replace(const basic_string<charT>& s, - const basic_regex<charT, traits>& e, - const charT* fmt, - regex_constants::match_flag_type flags = - regex_constants::match_default); +

    [ +2009-07 Frankfurt: +]

    -template <class traits, class charT> - basic_string<charT> - regex_replace(const charT* s, - const basic_regex<charT, traits>& e, - const basic_string<charT>& fmt, - regex_constants::match_flag_type flags = - regex_constants::match_default); -template <class traits, class charT> - basic_string<charT> - regex_replace(const charT* s, - const basic_regex<charT, traits>& e, - const charT* fmt, - regex_constants::match_flag_type flags = - regex_constants::match_default); - +
    +Daniel to provide wording. +N2590 +is no longer applicable.
    +

    [ +2009-07-28 Daniel provided wording. +]

    + +
    +
      +
    1. +It assumes that the proposed resolution for 883 is applied, +which breaks the circularity of definition between member +swap and free swap. +
      2. +
    2. +It uses the notation of the pre-concept allocator trait +allocator_propagation_map, which might be renamed after the +next refactoring phase of generalized allocators. +
      3. +
    3. +It requires that compare objects, key equal functions and +hash functions in containers are swapped via unqualified free +swap according to 594. +
      4. +
    +
    -
    -

    727. regex_replace() doesn't accept basic_strings with custom traits and allocators

    -

    Section: 28.12.4 [re.alg.replace] Status: Open - Submitter: Stephan T. Lavavej Opened: 2007-09-22 Last modified: 2009-05-23

    -

    View other active issues in [re.alg.replace].

    -

    View all other issues in [re.alg.replace].

    -

    View all issues with Open status.

    -

    Discussion:

    +

    Proposed resolution:

    +
      +

    1. -regex_match() and regex_search() take const basic_string<charT, ST, -SA>&. regex_replace() takes const basic_string<charT>&. This prevents -regex_replace() from accepting basic_strings with custom traits and -allocators. +Add a new Throws clause just after X [allocator.propagation.map]/5:

      -

      [ -Batavia (2009-05): -]

      - +
      static void swap(Alloc& a, Alloc& b);
+

      -Bill comments, "We need to look at the depth of this change." +Effects: [..]

      +

      -Pete remarks that we are here dealing with a convenience function -that saves a user from calling the iterato-based overload. +Throws: Nothing.

      +
      +
      +

      [ +This exception requirement is added, such that it's combination with the +general container requirements of +N2723 +[container.requirements.general]/9 +make it unambiguously clear that the following descriptions of "swaps the +allocators" have the following meaning: (a) This swap is done by calling +allocator_propagation_map<allocator_type>::swap and (b) This allocator +swap does never propagate an exception +]

      + +
      2. + +

    2. -Move to Open. +Change 23.2.4.1 [associative.reqmts.except]/3 as indicated:

      + +
      +For associative containers, no swap function throws an exception unless that +exception is thrown by the copy constructor or copy assignment +operator +swap of the container's Pred objects (if any).
      +
      3. +
    3. +

      +Change 23.2.5.1 [unord.req.except]/3 as indicated: +

      -

      Proposed resolution:

      +
      +For unordered associative containers, no swap function throws an +exception unless +that exception is thrown by the copy constructor or copy +assignment operator +swap of the container's Hash or Pred objects, +respectively (if any). +
      +
      4. + +

    4. -Overloads of regex_replace() taking basic_string should be additionally -templated on class ST, class SA and take const basic_string<charT, ST, -SA>&. Consistency with regex_match() and regex_search() would place -class ST, class SA as the first template arguments; compatibility with -existing code using TR1 and giving explicit template arguments to -regex_replace() would place class ST, class SA as the last template -arguments. +Insert a new paragraph just after 23.3 [sequences]/1:

      +
      +In addition to being available via inclusion of the <algorithm> header, +the swap function templates in 25.4.3 [alg.swap] are also available when the +header <queue> is included. +
      +

      [ +There is a new issue in process that will suggest a minimum header for swap +and move. If this one is provided, this text can be removed and the header +dependency should be added to <queue> +]

      +
      5. -
      -

      747. We have 3 separate type traits to identify classes supporting no-throw operations

      -

      Section: 20.6.4.3 [meta.unary.prop] Status: Open - Submitter: Alisdair Meredith Opened: 2007-10-10 Last modified: 2008-03-11

      -

      View other active issues in [meta.unary.prop].

      -

      View all other issues in [meta.unary.prop].

      -

      View all issues with Open status.

      -

      Discussion:

      -

      -We have 3 separate type traits to identify classes supporting no-throw -operations, which are very useful when trying to provide exception safety -guarantees. However, I'm not entirely clear on what the current wording -requires of a conforming implementation. To quote from -has_nothrow_default_constructor: -

      -

      -or T is a class type with a default constructor that is known not to throw -any exceptions -

      -

      -What level of magic do we expect to deduce if this is known? -

      +

    5. -E.g. +Add one further clause at the end of 23.3.1.2 [array.special]:

      +

      [This part is added, because otherwise array::swap would otherwise +contradict the +general contract of 23.2.1 [container.requirements.general] p. 10 b. 5]

      -
      struct test{
- int x;
- test() : x() {}
-};
-
      -

      -Should I expect a conforming compiler to - assert( has_nothrow_constructor<test>::value ) -

      + +
      +Throws: Nothing, unless one of the element-wise swap calls throws +an exception. +
      +
      6. + +
    6. +
        +

      1. -Is this a QoI issue? +In 23.3.2 [deque], class template deque synopsis change as indicated:

        +
        void swap(deque<T,Alloc>&);
+
        +
        2. + +

      2. -Should I expect to 'know' only if-and-only-if there is an inline definition -available? +At the end of 23.3.2.3 [deque.modifiers] add as indicated:

        + +
        void swap(deque& x);
+
        +

        -Should I never expect that to be true, and insist that the user supplies an -empty throw spec if they want to assert the no-throw guarantee? +Effects: Exchanges the contents and swaps the allocators of *this +with that of x.

        -It would be helpful to maybe have a footnote explaining what is required, -but right now I don't know what to suggest putting in the footnote. +Complexity: Constant time.

        +
        +
        +
        3. +
      +
      7. + +
    7. +
        +

      1. -(agreement since is that trivial ops and explicit no-throws are required. -Open if QoI should be allowed to detect further) +In 23.3.3 [forwardlist], class template forward_list synposis change as indicated:

        -

        [ -Bellevue: -]

        +
        void swap(forward_list<T,Allocator>&);
+
        +
        2. +
      2. +

        +At the end of 23.3.3.4 [forwardlist.modifiers] add as indicated: +

        +
        void swap(forward_list& x);
+
        -This looks like a QoI issue. -In the case of trivial and nothrow it is known. Static analysis of the program is definitely into QoI. -Move to OPEN. Need to talk to Core about this. +

        +Effects: Exchanges the contents and swaps the allocators of *this +with that of x. +

        +

        +Complexity: Constant time. +

        +
        +
        3. +
      +
      8. - -

      Proposed resolution:

      +
    8. +
        +

      1. +In 23.3.4 [list], class template list synopsis change as indicated:

        +
        void swap(list<T,Allocator>&);
+
        +
        2. - - - -
        -

        750. The current definition for is_convertible requires that the type be -implicitly convertible, so explicit constructors are ignored.

        -

        Section: 20.6.5 [meta.rel] Status: Open - Submitter: Alisdair Meredith Opened: 2007-10-10 Last modified: 2008-03-11

        -

        View other active issues in [meta.rel].

        -

        View all other issues in [meta.rel].

        -

        View all issues with Open status.

        -

        Discussion:

        +

      2. -With the pending arrival of explicit conversion functions though, I'm -wondering if we want an additional trait, is_explictly_convertible? +At the end of 23.3.4.3 [list.modifiers] add as indicated:

        -

        [ -Bellevue: -]

        - +
        void swap(list& x);
+
        -Alisdair is considering preparing a paper listing a number of missing -type traits, and feels that it might be useful to handle them all -together rather than piecemeal. This would affect issue 719 and 750. -These two issues should move to OPEN pending AM paper on type traits. -
        - - -

        Proposed resolution:

        +Effects: Exchanges the contents and swaps the allocators of *this +with that of x.

        +

        +Complexity: Constant time. +

        +
        + +
        3. +
      +
      9. +
    9. +

      +At the end of 23.3.5.2.2 [priqueue.members] add a new prototype description: +

      - - -
      -

      751. change pass-by-reference members of vector<bool> to pass-by-value?

      -

      Section: 23.3.7 [vector.bool] Status: Open - Submitter: Alisdair Meredith Opened: 2007-10-10 Last modified: 2008-09-22

      -

      View other active issues in [vector.bool].

      -

      View all other issues in [vector.bool].

      -

      View all issues with Open status.

      -

      Discussion:

      +
      void swap(priority_queue& q);
+
      +

      -A number of vector<bool> members take const bool& as arguments. -Is there any chance we could change them to pass-by-value or would I -be wasting everyone's time if wrote up an issue? +Requires: Compare shall satisfy the Swappable requirements +( [swappable]).

      [ -post Bellevue: +This requirement is added to ensure that even a user defined swap +which is found by +ADL for Compare satisfies the Swappable requirements ]

      -
      -

      -As we understand it, the original requester (Martin Sebor) would like -for implementations to be permitted to pass-by-value. Alisdair suggests -that if this is to be resolved, it should be resolved more generally, -e.g. in other containers as well. -

      -We note that this would break ABI. However, we also suspect that this -might be covered under the "as-if" rule in section 1.9. +Effects: this->c.swap(q.c); swap(this->comp, q.comp);

      -Many in the group feel that for vector<bool>, this is a "don't care", -and that at this point in the process it's not worth the bandwidth. -

      -

      -Issue 679 -- which was in ready status pre-Bellevue and is -now in the working paper -- is related to this, though not a duplicate. -

      -

      -Moving to Open with a task for Alisdair to craft a informative note to -be put whereever appropriate in the WP. This note would clarify places -where pass-by-const-ref can be transformed to pass-by-value under the -as-if rule. +Throws: What and if c.swap(q.c) and swap(comp, q.comp) throws.

      - +

      [ -San Francisco: +This part is added, because otherwise priority_queue::swap would otherwise +contradict the general contract of 23.2.1 [container.requirements.general] p. 10 b. 5 ]

      +
      10. -
      -

      -This is really a clause 17 issue, rather than something specific to vector<bool>. -

      +
    10. +
        +

      1. -Move to Open. Alisdair to provide a resolution. Alternately, Howard can -close this as NAD and then open a new issue to handle the general issue -(rather than the vector<bool> one). +In 23.3.6 [vector], class template vector synopsis change as indicated:

        + +
        void swap(vector<T,Allocator>&);
+
        +
        2. + +

      2. -Howard: Haven't yet opened new issue. Lacking wording for it. +Change 23.3.6.2 [vector.capacity]/8 as indicated:

        -
      11. +
      void swap(vector<T,Allocator>& x);
+
      -

      Proposed resolution:

      +
      +Effects: Exchanges the contents and capacity() and swaps the +allocators +of *this with that of x. +
      +
      + +
    + + +

  • +Insert a new paragraph just before 23.4 [associative]/1:

    +
    +In addition to being available via inclusion of the <algorithm> header, +the swap function templates in 25.4.3 [alg.swap] are also available when any of the +headers <map> or <set> are included. +
    +
    • +
  • +
      +
    1. +

      +In 23.4.1 [map], class template map synopsis change as indicated: +

      +
      void swap(map<Key,T,Compare,Allocator>&);
+
      +
      2. - -
      -

      760. The emplace issue

      -

      Section: 23.2 [container.requirements] Status: Open - Submitter: Paolo Carlini Opened: 2007-11-11 Last modified: 2008-06-02

      -

      View other active issues in [container.requirements].

      -

      View all other issues in [container.requirements].

      -

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      -

      Discussion:

      +

    2. -In an emplace member function the function parameter pack may be bound -to a priori unlimited number of objects: some or all of them can be -elements of the container itself. Apparently, in order to conform to the -blanket statement 23.2 [container.requirements]/11, the implementation must check all of them for -that possibility. A possible solution can involve extending the -exception in 23.2 [container.requirements]/12 also to the emplace member. As a side note, the -push_back and push_front member functions are luckily not affected by -this problem, can be efficiently implemented anyway +At the end of 23.4.1.3 [map.modifiers] add as indicated:

      -

      [ -Related to 767 -]

      +
      void swap(map& x);
+
      +
      +

      +Requires: Compare shall satisfy the Swappable requirements +( [swappable]). +

      [ -Bellevue: +This requirement is added to ensure that even a user defined swap +which is found by ADL for Compare satisfies the Swappable +requirements ]

      -

      -The proposed addition (13) is partially redundant with the existing -paragraph 12. Why was the qualifier "rvalues" added to paragraph 12? Why -does it not cover subelements and pointers? +Effects: Exchanges the contents and swaps the allocators of *this +with that of x, followed by an unqualified swap of the comparison objects +of *this and x.

      +

      -Resolution: Alan Talbot to rework language, then set state to Review. +Complexity: Constant time

      +
      +
      3. +
    +
    • +
  • +
      +
    1. +

      +In 23.4.2 [multimap], class template multimap synopsis change as indicated: +

      +
      void swap(multimap<Key,T,Compare,Allocator>&);
+
      +
      2. -

      Proposed resolution:

      +

    2. -Add after 23.2 [container.requirements]/12: +At the end of 23.4.2.2 [multimap.modifiers] add as indicated:

      +
      void swap(multimap& x);
+
      +

      --12- Objects passed to member functions of a container as rvalue references shall not be elements of that container. No -diagnostic required. +Requires: Compare shall satisfy the Swappable requirements +( [swappable]).

      - --13- Objects bound to the function parameter pack of the emplace member function shall not be elements or -sub-objects of elements of the container. No diagnostic required. - +Effects: Exchanges the contents and swaps the allocators of *this +with that of x, followed by an unqualified swap of the comparison objects +of *this and x. +

      +

      +Complexity: Constant time

      -
      +
      +
      3. +
    +
    • +
  • +
      +
    1. +

      +In 23.4.3 [set], class template set synopsis change as indicated: +

      +
      void swap(set<Key,Compare,Allocator>&);
+
      +
      2. +
    2. +

      +After section 23.4.3.1 [set.cons] add a new section set modifiers + [set.modifiers] +and add the following paragraphs: +

      +
      void swap(set& x);
+
      +
      +

      +Requires: Compare shall satisfy the Swappable requirements +( [swappable]). +

      -
      -

      765. more on iterator validity

      -

      Section: 24.2 [iterator.concepts] Status: Tentatively Ready - Submitter: Martin Sebor Opened: 2007-12-14 Last modified: 2009-03-09

      -

      View other active issues in [iterator.concepts].

      -

      View all other issues in [iterator.concepts].

      -

      View all issues with Tentatively Ready status.

      -

      Discussion:

      -

      - -Issue 278 -defines the meaning of the term "invalid iterator" as one that may be -singular. +

      +Effects: Exchanges the contents and swaps the allocators of *this +with that of x, followed by an unqualified swap of the comparison objects +of *this and x. +

      -

      -

      +

      +Complexity: Constant time +

      +
      +
      +
      3. +
    +
    • -Consider the following code: +
  • +
      +
    1. +

      +In 23.4.4 [multiset], class template multiset synosis, change as indicated: +

      -

      - 
         std::deque<int> x, y;
-   std::deque<int>::iterator i = x.end(), j = y.end();
-   x.swap(y);
-
      -

      +

      void swap(multiset<Key,Compare,Allocator>&);
+
      +
      2. -Given that swap() is required not to invalidate iterators -and using the definition above, what should be the expected result of -comparing i and j to x.end() -and y.end(), respectively, after the swap()? +
    2. +

      +After section 23.4.4.1 [multiset.cons] add a new section multiset modifiers + [multiset.modifiers] and add the following paragraphs: +

      -

      -

      +

      void swap(multiset& x);
+
      -I.e., is the expression below required to evaluate -to true? +
      +

      +Requires: Compare shall satisfy the Swappable requirements +( [swappable]). +

      -

      - 
         i == y.end() && j == x.end()
-
      -

      +

      +Effects: Exchanges the contents and swaps the allocators of *this +with that of x, followed by an unqualified swap of the comparison objects +of *this and x. +

      -(There are at least two implementations where the expression -returns false.) +

      +Complexity: Constant time +

      +
      +
      +
      3. +
    +
    • -

    -

    +

  • +

    +Insert a new paragraph just before 23.5 [unord]/1: +

    -More generally, is the definition introduced in issue 278 meant to -make any guarantees about whether iterators actually point to the same -elements or be associated with the same containers after a -non-invalidating operation as they did before? +
    +In addition to being available via inclusion of the <algorithm> header, +the swap function templates in 25.4.3 [alg.swap] are also available when any of the +headers <unordered_map> or <unordered_set> are included. +
    -

    -

    +

    • -Here's a motivating example intended to demonstrate the importance of -the question: +
  • +

    +After section 23.5.1.2 [unord.map.elem] add a new section unordered_map +modifiers [unord.map.modifiers] and add the following paragraphs: +

    -

    - 
       Container x, y ({ 1, 2});   // pseudocode to initialize y with { 1, 2 }
-   Container::iterator i = y.begin() + 1;
-   Container::iterator j = y.end();
-   std::swap(x, y);
-   std::find(i, j, 3);
-
    -

    +

    void swap(unordered_map& x);
+
    -swap() guarantees that i and j -continue to be valid. Unless the spec says that even though they are -valid they may no longer denote a valid range the code above must be -well-defined. Expert opinions on this differ as does the behavior of -popular implementations for some standard Containers. +
    +

    +Requires: Hash and Pred shall satisfy the Swappable requirements +( [swappable]). +

    -

    [ -San Francisco: +This requirement is added to ensure that even a user defined swap +which is found by ADL for Hash and Pred satisfies the Swappable +requirements ]

    -
    -

    Pablo: add a note to the last bullet of paragraph 11 of 23.1.1 -clarifying that the end() iterator doesn't refer to an element and that -it can therefore be invalidated. -

    -Proposed wording: +Effects: Exchanges the contents and hash policy and swaps the +allocators of *this +with that of x, followed by an unqualified swap of the Pred objects +and an unqualified swap of the Hash objects of *this and x.

    -
    -[Note: The end() iterator does not refer to any element and can -therefore be invalidated. -- end note] -
    +

    -Howard will add this proposed wording to the issue and then move it to Review. +Complexity: Constant time

    +
    +
    • -

    [ -Post Summit: -]

    +
  • +

    +After section 23.5.2.1 [unord.multimap.cnstr] add a new section +unordered_multimap +modifiers [unord.multimap.modifiers] and add the following paragraphs: +

    +
    void swap(unordered_multimap& x);
+

    -Lawrence: suggestion: "Note: The end() iterator does not refer to any element" -

    -

    -Walter: "Note: The end() iterator can nevertheless be invalidated, -because it does not refer to any element." -

    -

    -Nick: "The end() iterator does not refer to any element. It is therefore -subject to being invalidated." +Requires: Hash and Pred shall satisfy the Swappable requirements +( [swappable]).

    +

    -Consensus: go with Nick +Effects: Exchanges the contents and hash policy and swaps the +allocators of *this +with that of x, followed by an unqualified swap of the Pred objects +and an unqualified swap of the Hash objects of *this and x

    -With that update, Recommend Tentatively Ready. +Complexity: Constant time

    +
    +
    • - - -

    Proposed resolution:

    +

  • -Add to 23.2.1 [container.requirements.general], p11: +After section 23.5.3.1 [unord.set.cnstr] add a new section +unordered_set modifiers + [unord.set.modifiers] and add the following paragraphs:

    +
    void swap(unordered_set& x);
+
    +

    -Unless otherwise specified (see 23.1.4.1, 23.1.5.1, 23.2.2.3, and -23.2.6.4) all container types defined in this Clause meet the following -additional requirements: +Requires: Hash and Pred shall satisfy the Swappable requirements +( [swappable]).

    -
      -
    • ...
      • -
    • -no swap() function invalidates any references, pointers, or -iterators referring to the elements of the containers being swapped. -[Note: The end() iterator does not refer to any element. It is therefore -subject to being invalidated. -- end note] -
      • -
    -
    - - - - -
    -

    774. Member swap undefined for most containers

    -

    Section: 23 [containers] Status: Open - Submitter: Alisdair Meredith Opened: 2008-01-14 Last modified: 2008-05-11

    -

    View other active issues in [containers].

    -

    View all other issues in [containers].

    -

    View all issues with Open status.

    -

    Discussion:

    -It appears most containers declare but do not define a member-swap -function. +Effects: Exchanges the contents and hash policy and swaps the +allocators of *this +with that of x, followed by an unqualified swap of the Pred objects +and an unqualified swap of the Hash objects of *this and x

    -This is unfortunate, as all overload the swap algorithm to call the -member-swap function! -(required for swappable guarantees [Table 37] and Container Requirements -[Table 87]) +Complexity: Constant time

    +
    + +
    • +

  • -Note in particular that Table 87 gives semantics of a.swap(b) as swap(a,b), -yet for all containers we define swap(a,b) to call a.swap(b) - a circular -definition. +After section 23.5.4.1 [unord.multiset.cnstr] add a new section +unordered_multiset +modifiers [unord.multiset.modifiers] and add the following paragraphs:

    +
    void swap(unordered_multiset& x);
+
    + +

    -A quick survey of clause 23 shows that the following containers provide a -definition for member-swap: +Requires: Hash and Pred shall satisfy the Swappable requirements +( [swappable]).

    -
    array
-queue
-stack
-vector
-
    -

    -Whereas the following declare it, but do not define the semantics: +Effects: Exchanges the contents and hash policy and swaps the +allocators of *this +with that of x, followed by an unqualified swap of the Pred objects +and an unqualified swap of the Hash objects of *this and x

    - -
    deque
-list
-map
-multimap
-multiset
-priority_queue
-set
-unordered_map
-unordered_multi_map
-unordered_multi_set
-unordered_set
-
    -

    -Suggested resolution: +Complexity: Constant time

    -
    -Provide a definition for each of the affected containers...
    - -

    [ -Bellevue: -]

    - - -
    -Move to Open and ask Alisdair to provide wording.
    +
    • + -

    Proposed resolution:

    -

    -Wording provided in -N2590. -

    @@ -9837,9 +9245,9 @@ Wording provided in

    780. std::merge() specification incorrect/insufficient

    -

    Section: 25.5.4 [alg.merge] Status: Review - Submitter: Daniel Krügler Opened: 2008-01-25 Last modified: 2009-05-23

    -

    View all issues with Review status.

    +

    Section: 25.5.4 [alg.merge] Status: Ready + Submitter: Daniel Krügler Opened: 2008-01-25 Last modified: 2009-07-16

    +

    View all issues with Ready status.

    Discussion:

    Though issue 283 has fixed many open issues, it seems that some are still open: @@ -9927,6 +9335,16 @@ Move to Review.

    +

    [ +2009-07 Frankfurt: +]

    + + +
    +Move to Ready. +
    + +

    Proposed resolution:

    @@ -9967,94 +9385,12 @@ other parts of <algorithm> show, just a matter of consistency]

    -

    785. Random Number Requirements in TR1

    -

    Section: TR1 5.1.4.5 [tr.rand.eng.disc], TR1 5.1.4.6 [tr.rand.eng.xor] Status: Tentatively NAD - Submitter: John Maddock Opened: 2008-01-15 Last modified: 2009-05-23

    -

    View all issues with Tentatively NAD status.

    -

    Discussion:

    -

    -Table 16 of TR1 requires that all Pseudo Random Number generators have a -

    - -
    seed(integer-type s)
-
    - -

    -member function that is equivalent to: -

    - -
    mygen = Generator(s)
-
    - -

    -But the generators xor_combine and discard_block have no such seed member, only the -

    - -
    template <class Gen>
-seed(Gen&);
-
    - -

    -member, which will not accept an integer literal as an argument: something that appears to violate the intent of Table 16. -

    - -

    -So... is this a bug in TR1? -

    - -

    This is a real issue BTW, since the Boost implementation does adhere -to the requirements of Table 16, while at least one commercial -implementation does not and follows a strict adherence to sections -5.1.4.5 and 5.1.4.6 instead. -

    - -

    [ -Jens adds: -]

    - - -
    -Both engines do have the necessary -constructor, therefore the omission of the seed() member -functions appears to be an oversight. -
    - -

    [ -Post Summit Daniel adds: -]

    - - -
    -Recommend NAD: xor_combine does no longer exist and discard_block[_engine] -has now the required seed overload accepting a result_type, which shall be an -unsigned integral type. -
    - -

    [ -Batavia (2009-05): -]

    - -
    -Move to NAD as recommended. -
    - - -

    Proposed resolution:

    -

    -NAD Recommended. -

    - - - - - -

    788. ambiguity in [istream.iterator]

    -

    Section: 24.6.1 [istream.iterator] Status: Open - Submitter: Martin Sebor Opened: 2008-02-06 Last modified: 2009-03-14

    +

    Section: 24.6.1 [istream.iterator] Status: Ready + Submitter: Martin Sebor Opened: 2008-02-06 Last modified: 2009-07-16

    View other active issues in [istream.iterator].

    View all other issues in [istream.iterator].

    -

    View all issues with Open status.

    +

    View all issues with Ready status.

    Discussion:

    Addresses UK 287

    @@ -10124,6 +9460,21 @@ Moved from Ready to Open for the purposes of using this issue to address NB UK 2 Martin to handle. +

    [ +2009-07 Frankfurt: +]

    + + +
    +

    +This improves the wording. +

    +

    +Move to Ready. +

    +
    + +

    Proposed resolution:

    @@ -10156,7 +9507,7 @@ is used a new value is read.

    801. tuple and pair trivial members

    Section: 20.5 [tuple] Status: Open - Submitter: Lawrence Crowl Opened: 2008-02-18 Last modified: 2009-05-30

    + Submitter: Lawrence Crowl Opened: 2008-02-18 Last modified: 2009-07-20

    View all other issues in [tuple].

    View all issues with Open status.

    Discussion:

    @@ -10259,182 +9610,140 @@ tabled until Alisdair's proposals are disposed of. This is partly solved by 1117. - -

    Proposed resolution:

    -

    -

    - - +

    [ +2009-07 Frankfurt: +]

    +
    +Wait for dust to settle from fixing exception safety problem +with rvalue refs. +
    -
    -

    810. Missing traits dependencies in operational semantics of extended manipulators

    -

    Section: 27.7.4 [ext.manip] Status: Tentatively Ready - Submitter: Daniel Krügler Opened: 2008-03-01 Last modified: 2009-05-23

    -

    View all other issues in [ext.manip].

    -

    View all issues with Tentatively Ready status.

    -

    Discussion:

    -

    -The recent draft (as well as the original proposal n2072) uses an -operational semantic -for get_money ([ext.manip]/4) and put_money ([ext.manip]/6), which uses -

    +

    [ +2009-07-20 Alisdair adds: +]

    -
    istreambuf_iterator<charT>
-
    +

    -and +Basically, this issue is what should we do with the default constructor +for pairs and tuples of trivial types. The motivation of the issue was +to force static initialization rather than dynamic initialization, and +was rejected in the case of pair as it would change the meaning of +existing programs. The advice was "do the best we can" for tuple +without changing existing meaning.

    -
    ostreambuf_iterator<charT>
-
    - -

    -resp, instead of the iterator instances, with explicitly provided -traits argument (The operational semantic defined by f is also traits -dependent). This is an obvious oversight because both *stream_buf -c'tors expect a basic_streambuf<charT,traits> as argument. -

    -The same problem occurs within the get_time and put_time semantic -where additional to the problem we -have an editorial issue in get_time (streambuf_iterator instead of -istreambuf_iterator). +Frankfurt seems to simply wait and see the resolution on no-throw move +constructors, which (I believe) is only tangentially related to this +issue, but as good as any to defer until Santa Cruz.

    -

    [ -Batavia (2009-05): -]

    - -

    -This appears to be an issue of presentation. -

    -

    -We agree with the proposed resolution. -Move to Tentatively Ready. +Looking again now, I think constant (static) initialization for pair can +be salvaged by making the default construct constexpr. I have a +clarification from Core that this is intended to work, even if the +constructor is not trivial/constexpr, so long as no temporaries are +implied in the process (even if elided).

    +

    Proposed resolution:

    -In 27.7.4 [ext.manip]/4 within function f replace the first line

    -
    template <class charT, class traits, class moneyT> 
-void f(basic_ios<charT, traits>& str, moneyT& mon, bool intl) { 
-   typedef istreambuf_iterator<charT, traits> Iter;
-   ...
-
    -

    -In 27.7.4 [ext.manip]/5 remove the first template charT parameter: -

    -
    template <class charT, class moneyT> unspecified put_money(const moneyT& mon, bool intl = false);
-
    -

    -In 27.7.4 [ext.manip]/6 within function f replace the first line -

    -
    template <class charT, class traits, class moneyT> 
-void f(basic_ios<charT, traits>& str, const moneyT& mon, bool intl) { 
-  typedef ostreambuf_iterator<charT, traits> Iter;
-  ...
+
    
+
    811. pair of pointers no longer works with literal 0
    
+
    Section: 20.3.3 [pairs] Status: Open
+ Submitter: Doug Gregor Opened: 2008-03-14  Last modified: 2009-07-28
    
+
    View other active issues in [pairs].
    
+
    View all other issues in [pairs].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
+
    #include <utility>
+
+int main()
+{
+   std::pair<char *, char *> p (0,0);
+}
 
    
 
 
    
-In 27.7.4 [ext.manip]/8 within function f replace the first line
+I just got a bug report about that, because it's valid C++03, but not
+C++0x. The important realization, for me, is that the emplace
+proposal---which made push_back variadic, causing the push_back(0)
+issue---didn't cause this break in backward compatibility. The break
+actually happened when we added this pair constructor as part of adding
+rvalue references into the language, long before variadic templates or
+emplace came along:
 
    
 
-
    template <class charT, class traits> 
-void f(basic_ios<charT, traits>& str, struct tm *tmb, const charT *fmt) { 
-  typedef istreambuf_iterator<charT, traits> Iter;
-  ...
+
    template<class U, class V> pair(U&& x, V&& y);
 
    
 
 
    
-In 27.7.4 [ext.manip]/10 within function f replace the first line
+Now, concepts will address this issue by constraining that pair
+constructor to only U's and V's that can properly construct "first" and
+"second", e.g. (from
+N2322):
 
    
 
-
    template <class charT, class traits> 
-void f(basic_ios<charT, traits>& str, const struct tm *tmb, const charT *fmt) { 
-  typedef ostreambuf_iterator<charT, traits> Iter;
-  ...
+
    template<class U , class V >
+requires Constructible<T1, U&&> && Constructible<T2, V&&>
+pair(U&& x , V&& y );
 
    
 
+
    [
+San Francisco:
+]
    
+
+
+
    
 
    
-In 27.7 [iostream.format], Header <iomanip> synopsis change:
+Suggested to resolve using pass-by-value for that case.
 
    
+
    
+Side question: Should pair interoperate with tuples? Can construct a
+tuple of a pair, but not a pair from a two-element tuple.
+
    
+
    
+Related to 885.
+
    
+
    
 
-
    template <class charT, class moneyT> T8 put_money(const moneyT& mon, bool intl = false);
-
    
-
+
    [
+2009-07-28 Reopened by Alisdair.  No longer solved by concepts.
+]
    
 
 
 
 
-
    
-
    814. vector<bool>::swap(reference, reference) not defined
    
-
    Section: 23.3.7 [vector.bool] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2008-03-17  Last modified: 2009-05-23
    
-
    View other active issues in [vector.bool].
    
-
    View all other issues in [vector.bool].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
+
    Proposed resolution:
    
 
    
-vector<bool>::swap(reference, reference) has no definition.
 
    
 
+
+
    Rationale:
    
 
    [
 San Francisco:
 ]
    
 
 
 
    
-Move to Open. Alisdair to provide a resolution.
+Solved by
+N2770.
 
    
 
-
    [
-Post Summit Daniel provided wording.
-]
    
 
 
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
-
    
-
-
-
    Proposed resolution:
    
-
    
-Just after 23.3.7 [vector.bool]/5 add the following prototype and description:
-
    
-
-
    
-
    
-static void swap(reference x, reference y);
-
    
-
    
-
    
--6- Effects: Exchanges the contents of x and y as-if by:
-
    
-
    
-bool b = x;
-x = y;
-y = b;
-
    
-
    
-
    
-
 
 
 
@@ -10442,7 +9751,7 @@ y = b;
 
    
 
    815. std::function and reference_closure do not use perfect forwarding
    
 
    Section: 20.7.16.2.4 [func.wrap.func.inv] Status: Open
- Submitter: Alisdair Meredith Opened: 2008-03-16  Last modified: 2009-06-01
    
+ Submitter: Alisdair Meredith Opened: 2008-03-16  Last modified: 2009-07-16
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
@@ -10608,6 +9917,17 @@ do so, if ArgTypes aren't at least MoveConstructible?
 
    
 
    
 
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+Leave this open and wait until concepts are removed from the Working
+Draft so that we know how to write the proposed resolution in terms of
+diffs to otherwise stable text.
+
    
+
 
 
 
    Proposed resolution:
    
@@ -10621,7 +9941,7 @@ do so, if ArgTypes aren't at least MoveConstructible?
 
    
 
    816. Should bind()'s returned functor have a nofail copy ctor when bind() is nofail?
    
 
    Section: 20.7.12.1.3 [func.bind.bind] Status: Open
- Submitter: Stephan T. Lavavej Opened: 2008-02-08  Last modified: 2009-05-23
    
+ Submitter: Stephan T. Lavavej Opened: 2008-02-08  Last modified: 2009-07-16
    
 
    View other active issues in [func.bind.bind].
    
 
    View all other issues in [func.bind.bind].
    
 
    View all issues with Open status.
    
@@ -10681,6 +10001,16 @@ to ensure there is no overlap.
 Move to Open, and likewise for issue 817.
 
    
 
+
    [
+2009-07 Frankfurt:
+]
    
+
+
+
    
+Related to 817 (see below). Leave Open.
+
    
+
+
 
 
    Proposed resolution:
    
 
    
@@ -10716,7 +10046,7 @@ in BoundArgs... throw an exception.
 
    
 
    817. bind needs to be moved
    
 
    Section: 20.7.12.1.3 [func.bind.bind] Status: Open
- Submitter: Howard Hinnant Opened: 2008-03-17  Last modified: 2009-05-23
    
+ Submitter: Howard Hinnant Opened: 2008-03-17  Last modified: 2009-07-16
    
 
    View other active issues in [func.bind.bind].
    
 
    View all other issues in [func.bind.bind].
    
 
    View all issues with Open status.
    
@@ -10836,6 +10166,16 @@ and recommend both issues be considered together
    +

    [ +2009-07 Frankfurt: +]

    + + +
    +The proposed resolution uses concepts. Leave Open. +
    + +

    Proposed resolution:

    @@ -10990,10 +10330,11 @@ Alisdair was volunteered to provide wording.

    822. Object with explicit copy constructor no longer CopyConstructible

    -

    Section: X [utility.arg.requirements] Status: Tentatively NAD - Submitter: James Kanze Opened: 2008-04-01 Last modified: 2009-05-23

    +

    Section: X [utility.arg.requirements] Status: Ready + Submitter: James Kanze Opened: 2008-04-01 Last modified: 2009-07-26

    +

    View other active issues in [utility.arg.requirements].

    View all other issues in [utility.arg.requirements].

    -

    View all issues with Tentatively NAD status.

    +

    View all issues with Ready status.

    Discussion:

    I just noticed that the following program is legal in C++03, but @@ -11034,10 +10375,50 @@ The subgroup that looked at this felt this was a good change, but it may already be handled by incoming concepts (we're not sure).

    - -Original Proposed resolution: - +

    [ +Post Summit: +]

    + + +
    +

    +Alisdair: Proposed resolution kinda funky as these tables no longer +exist. Move from direct init to copy init. Clarify with Doug, recommends +NAD. +

    +

    +Walter: Suggest NAD via introduction of concepts. +

    +

    +Recommend close as NAD. +

    +
    + +

    [ +2009-07 Frankfurt: +]

    + + +
    +Need to look at again without concepts. +
    + +

    [ +2009-07 Frankfurt: +]

    + + +
    +

    +Move to Ready with original proposed resolution. +

    +

    [Howard: Original proposed resolution restored.]

    + +
    + + +

    Proposed resolution:

    In X [utility.arg.requirements] change Table 33: MoveConstructible requirements [moveconstructible]:

    @@ -11074,104 +10455,127 @@ In X [utility.arg.requirements] change Table 34: CopyConstructible requ -

    [ -Post Summit: -]

    - - -
    -

    -Alisdair: Proposed resolution kinda funky as these tables no longer -exist. Move from direct init to copy init. Clarify with Doug, recommends -NAD. -

    -

    -Walter: Suggest NAD via introduction of concepts. -

    -

    -Recommend close as NAD. -

    -
    - - - -

    Proposed resolution:

    -

    -Recommend close as NAD. -

    -
    -

    825. Missing rvalues reference stream insert/extract operators?

    -

    Section: 19.5.2.2 [syserr.errcode.overview], 20.8.13.2.8 -[util.smartptr.shared.io], 22.4.8 [facets.examples], 20.3.6.3 -[bitset.operators], 26.4.6 [complex.ops], 27.6 [stream.buffers], 28.10 -[re.submatch] Status: Tentatively NAD Editorial - Submitter: Alisdair Meredith Opened: 2008-04-10 Last modified: 2009-05-23

    -

    View all issues with Tentatively NAD Editorial status.

    +

    823. identity<void> seems broken

    +

    Section: 20.3.2 [forward] Status: Open + Submitter: Walter Brown Opened: 2008-04-09 Last modified: 2009-07-30

    +

    View other active issues in [forward].

    +

    View all other issues in [forward].

    +

    View all issues with Open status.

    Discussion:

    -Should the following use rvalues references to stream in insert/extract -operators? +N2588 seems to have added an operator() member function to the +identity<> helper in 20.3.2 [forward]. I believe this change makes it no +longer possible to instantiate identity<void>, as it would require +forming a reference-to-void type as this operator()'s parameter type.

    -
      -
    • 19.5.2.2 [syserr.errcode.overview]
      • -
    • 20.8.13.2.8 [util.smartptr.shared.io]
      • -
    • 22.4.8 [facets.examples]
      • -
    • 20.3.6.3 [bitset.operators]
      • -
    • 26.4.6 [complex.ops]
      • -
    • Doubled signatures in 27.6 [stream.buffers] for character inserters -(ref 27.7.2.6.4 [ostream.inserters.character]) -+ definition 27.7.2.6.4 [ostream.inserters.character]
      • -
    • 28.10 [re.submatch]
      • -
    +

    +Suggested resolution: Specialize identity<void> so as not to require +the member function's presence. +

    [ -Sophia Antipolis +Sophia Antipolis: ]

    -Agree with the idea in the issue, Alisdair to provide wording. +

    +Jens: suggests to add a requires clause to avoid specializing on void. +

    +

    +Alisdair: also consider cv-qualified void. +

    +

    +Alberto provided proposed wording. +

    [ -Daniel adds 2009-02-14: +2009-07-30 Daniel reopens: ]

    -The proposal given in the paper -N2831 -apparently resolves this issue. -
    +

    +This issue became closed, because the ReferentType requirement +fixed the problem - this is no longer the case. In retrospective it seems +to be that the root of current issues around std::identity (823, 700, +939) +is that it was standardized as something very different (an unconditional +type mapper) than traditional usage indicated (a function object that should +derive from std::unary_function), as the SGI definition does. This issue could +be solved, if std::identity is removed (one proposal of 939), but until this +has been decided, this issue should remain open. An alternative for +removing it, would be, to do the following: +

    -

    [ -Batavia (2009-05): -]

    +
      +
    1. +

      +Let identity stay as a real function object, which would +now properly +derive from unary_function: +

      -
      +
      template <class T> struct identity : unary_function<T, T> {
+  const T& operator()(const T&) const;
+};
+
      +
      2. + +

    2. -The cited paper is an earlier version of -N2844, -which changed the rvalue reference binding rules. -That paper includes generic templates -operator<< and operator>> -that adapt rvalue streams. +Invent (if needed) a generic type wrapper (corresponding to concept +IdentityOf), +e.g. identity_of, and move it's prototype description back to 20.3.2 [forward]:

      + +
      template <class T> struct identity_of {
+  typedef T type;
+};
+
      +

      -We therefore agree with Daniel's observation. -Move to NAD Editorial. +and adapt the std::forward signature to use identity_of +instead of identity.

      +
      3. +

    Proposed resolution:

    +Change definition of identity in 20.3.2 [forward], paragraph 2, to: +

    + +
    template <class T>  struct identity {
+    typedef T type;
+
+    requires ReferentType<T>
+      const T& operator()(const T& x) const;
+  };
+
    +

    ...

    +
      requires ReferentType<T>
+    const T& operator()(const T& x) const;
+
    + + +

    Rationale:

    +

    +The point here is to able to write T& given T and ReferentType is +precisely the concept that guarantees so, according to N2677 +(Foundational concepts). Because of this, it seems preferable than an +explicit check for cv void using SameType/remove_cv as it was suggested +in Sophia. In particular, Daniel remarked that there may be types other +than cv void which aren't referent types (int[], perhaps?).

    @@ -11180,8 +10584,8 @@ Move to NAD Editorial.

    827. constexpr shared_ptr::shared_ptr()?

    -

    Section: 20.8.13.2.1 [util.smartptr.shared.const] Status: Open - Submitter: Peter Dimov Opened: 2008-04-11 Last modified: 2009-05-30

    +

    Section: 20.8.10.2.1 [util.smartptr.shared.const] Status: Open + Submitter: Peter Dimov Opened: 2008-04-11 Last modified: 2009-07-21

    View other active issues in [util.smartptr.shared.const].

    View all other issues in [util.smartptr.shared.const].

    View all issues with Open status.

    @@ -11239,14 +10643,52 @@ literal types. Otherwise this should be closed as NAD. If Alisdair's 2009-05-01 comment is correct, wouldn't that also make constexpr mutex() useless, because this class has a non-trivial destructor? (828) + + +

    [ +2009-07-21 Alisdair adds: +]

    + + +
    +

    +The feedback from core is that this and similar uses of constexpr +constructors to force static initialization should be supported. If +there are any problems with this in the working draught, we should file +core issues. +

    +

    +Recommend we declare the default constructor constexpr as the issue suggests +(proposed wording added). +

    +

    Proposed resolution:

    +Change 20.8.10.2 [util.smartptr.shared] and 20.8.10.2.1 [util.smartptr.shared.const]: +

    + +
    consexpr shared_ptr();
+
    + +

    +Change 20.8.10.3 [util.smartptr.weak] and 20.8.10.3.1 [util.smartptr.weak.const]: +

    + +
    consexpr weak_ptr();
+
    + +

    +Change 20.8.10.5 [util.smartptr.enab] (2 places):

    +
    consexpr enable_shared_from_this();
+
    + + @@ -11349,31 +10791,45 @@ public:
    -

    830. Incomplete list of char_traits specializations

    -

    Section: 21.2 [char.traits] Status: Tentatively NAD Editorial - Submitter: Dietmar Kühl Opened: 2008-04-23 Last modified: 2009-05-23

    -

    View all other issues in [char.traits].

    -

    View all issues with Tentatively NAD Editorial status.

    +

    834. Unique_ptr::pointer requirements underspecified

    +

    Section: 20.8.9.2 [unique.ptr.single] Status: Ready + Submitter: Daniel Krügler Opened: 2008-05-14 Last modified: 2009-07-16

    +

    View other active issues in [unique.ptr.single].

    +

    View all other issues in [unique.ptr.single].

    +

    View all issues with Ready status.

    Discussion:

    - Paragraph 4 of 21.2 [char.traits] mentions that this - section specifies two specializations (char_traits<char> - and (char_traits<wchar_t>). However, there are actually - four specializations provided, i.e. in addition to the two above also - char_traits<char16_t> and char_traits<char32_t>). - I guess this was just an oversight and there is nothing wrong with just - fixing this. +Issue 673 (including recent updates by 821) proposes a useful +extension point for unique_ptr by granting support for an optional +deleter_type::pointer to act as pointer-like replacement for element_type* +(In the following: pointer). +

    +

    +Unfortunately no requirements are specified for the type pointer which has +impact on at least two key features of unique_ptr:

    -

    [ -Alisdair adds: -]

    +
      +
    1. Operational fail-safety.
      2. +
    2. (Well-)Definedness of expressions.
      3. +
    -
    -char_traits< char16/32_t > -should also be added to <ios_fwd> in 27.3 [iostream.forward], and all the specializations -taking a char_traits parameter in that header. -
    +

    +Unique_ptr specification makes great efforts to require that essentially *all* +operations cannot throw and therefore adds proper wording to the affected +operations of the deleter as well. If user-provided pointer-emulating types +("smart pointers") will be allowed, either *all* throw-nothing clauses have to +be replaced by weaker "An exception is thrown only if pointer's {op} throws +an exception"-clauses or it has to be said explicitly that all used +operations of +pointer are required *not* to throw. I understand the main focus of unique_ptr +to be as near as possible to the advantages of native pointers which cannot +fail and thus strongly favor the second choice. Also, the alternative position +would make it much harder to write safe and simple template code for +unique_ptr. Additionally, I assume that a general statement need to be given +that all of the expressions of pointer used to define semantics are required to +be well-formed and well-defined (also as back-end for 762). +

    [ Sophia Antipolis: @@ -11382,228 +10838,34 @@ Sophia Antipolis:

    -Idea of the issue is ok. +Howard: We maybe need a core concept PointerLike, but we don't need the +arithmetic (see shared_ptr vs. vector<T>::iterator.

    -Alisdair to provide wording, once that wording arrives, move to review. +Howard will go through and enumerate the individual requirements wrt. pointer for each member function.

    -

    [ -2009-05-04 Alisdair adds: +2009-07 Frankfurt: ]

    -

    -The main point of the issue was resolved editorially in -N2723, -so we are -close to NAD Editorial. -However, exploring the issue we found a second tweak was necessary for -<iosfwd> and that is still outstanding, so here are the words I am long -overdue delivering: -

    - -

    [ -Howard: I've put Alisdair's words into the proposed wording section and -moved the issue to Review. -]

    - - +Move to Ready.
    -

    [ -Original proposed wording. -]

    - -
    +

    Proposed resolution:

    - Replace paragraph 4 of 21.2 [char.traits] by: +Add the following sentence just at the end of the newly proposed +20.8.9.2 [unique.ptr.single]/p. 3:

    +
    -

    - This subclause specifies a struct template, char_traits<charT>, - and four explicit specializations of it, char_traits<char>, - char_traits<char16_t>, char_traits<char32_t>, and - char_traits<wchar_t>, all of which appear in the header - <string> and satisfy the requirements below. -

    -
    -
    - -

    [ -Batavia (2009-05): -]

    - -
    -We agree. Move to NAD Editorial. -
    - - -

    Proposed resolution:

    -

    -Change Forward declarations 27.3 [iostream.forward]: -

    - -
    -

    -Header <iosfwd> synopsis -

    -
    namespace std {
-   template<class charT> class char_traits;
-   template<> class char_traits<char>;
-   template<> class char_traits<char16_t>;
-   template<> class char_traits<char32_t>;
-   template<> class char_traits<wchar_t>;
-...
-}
-
    -
    - - - - - -
    -

    833. Freestanding implementations header list needs review for C++0x

    -

    Section: 17.6.1.3 [compliance] Status: Open - Submitter: Beman Dawes Opened: 2008-05-14 Last modified: 2009-03-11

    -

    View other active issues in [compliance].

    -

    View all other issues in [compliance].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -Once the C++0x standard library is feature complete, the LWG needs to -review 17.6.1.3 [compliance] Freestanding implementations header list to -ensure it reflects LWG consensus. -

    - -

    [ -San Francisco: -]

    - - -
    -

    -This is a placeholder defect to remind us to review the table once we've -stopped adding headers to the library. -

    -

    -Three new headers that need to be added to the list: -

    -
    <initializer_list> <concept> <iterator_concepts>
-
    -

    -<iterator_concepts>, in particular, has lots of stuff -that isn't needed, so maybe the stuff that is needed should be broken -out into a separate header. -

    -

    -Robert: What about reference_closure? It's currently in -<functional>. -

    -
    - -

    [ -Post Summit Daniel adds: -]

    - - -
    -
      -
    1. -The comment regarding reference_closure seems moot since it was just -recently decided to remove that. -
      2. -
    2. -A reference to proposal -N2814 -("Fixing freestanding") should be added. This -paper e.g. proposes to add only <initializer_list> to the include list -of freestanding. -
      3. -
    -
    - - - -

    Proposed resolution:

    - - - - - -
    -

    834. Unique_ptr::pointer requirements underspecified

    -

    Section: 20.8.12.2 [unique.ptr.single] Status: Open - Submitter: Daniel Krügler Opened: 2008-05-14 Last modified: 2008-06-19

    -

    View other active issues in [unique.ptr.single].

    -

    View all other issues in [unique.ptr.single].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -Issue 673 (including recent updates by 821) proposes a useful -extension point for unique_ptr by granting support for an optional -deleter_type::pointer to act as pointer-like replacement for element_type* -(In the following: pointer). -

    -

    -Unfortunately no requirements are specified for the type pointer which has -impact on at least two key features of unique_ptr: -

    - -
      -
    1. Operational fail-safety.
      2. -
    2. (Well-)Definedness of expressions.
      3. -
    - -

    -Unique_ptr specification makes great efforts to require that essentially *all* -operations cannot throw and therefore adds proper wording to the affected -operations of the deleter as well. If user-provided pointer-emulating types -("smart pointers") will be allowed, either *all* throw-nothing clauses have to -be replaced by weaker "An exception is thrown only if pointer's {op} throws -an exception"-clauses or it has to be said explicitly that all used -operations of -pointer are required *not* to throw. I understand the main focus of unique_ptr -to be as near as possible to the advantages of native pointers which cannot -fail and thus strongly favor the second choice. Also, the alternative position -would make it much harder to write safe and simple template code for -unique_ptr. Additionally, I assume that a general statement need to be given -that all of the expressions of pointer used to define semantics are required to -be well-formed and well-defined (also as back-end for 762). -

    - -

    [ -Sophia Antipolis: -]

    - - -
    -

    -Howard: We maybe need a core concept PointerLike, but we don't need the -arithmetic (see shared_ptr vs. vector<T>::iterator. -

    -

    -Howard will go through and enumerate the individual requirements wrt. pointer for each member function. -

    -
    - - - -

    Proposed resolution:

    -

    -Add the following sentence just at the end of the newly proposed -20.8.12.2 [unique.ptr.single]/p. 3: -

    - -
    -unique_ptr<T, D>::pointer's operations shall be well-formed, shall have well -defined behavior, and shall not throw exceptions. +unique_ptr<T, D>::pointer's operations shall be well-formed, shall have well +defined behavior, and shall not throw exceptions.
    @@ -11613,7 +10875,7 @@ defined behavior, and shall not throw exceptions.

    835. tying two streams together (correction to DR 581)

    Section: 27.5.4.2 [basic.ios.members] Status: Review - Submitter: Martin Sebor Opened: 2008-05-17 Last modified: 2009-05-30

    + Submitter: Martin Sebor Opened: 2008-05-17 Last modified: 2009-07-27

    View other active issues in [basic.ios.members].

    View all other issues in [basic.ios.members].

    View all issues with Review status.

    @@ -11711,48 +10973,64 @@ a return value of -1 of pubsync() produce setstate(badbit) +

    [ +2009-07 Frankfurt: +]

    -

    Proposed resolution:

    +
    +

    +Daniel volunteered to modify the proposed resolution to address his two questions. +

    +Move back to Open. +

    +
    -I think an easy way to plug the first hole is to add a requires clause -to ostream::tie(ostream *tiestr) requiring the this -pointer not be equal to any pointer on the list starting -with tiestr->tie() -through tiestr()->tie()->tie() and so on. I am not -proposing that we require implementations to traverse this list, -although I think we could since the list is unlikely to be very long. +

    [ +2009-07-26 Daniel provided wording. Moved to Review. +]

    -

    -

    -Add a Requires clause to 27.5.4.2 [basic.ios.members] withethe following -text: -

    -
    -Requires: If (tiestr != 0) is -true, tiestr must not be reachable by traversing the -linked list of tied stream objects starting -from tiestr->tie(). +

    Proposed resolution:

    +

    [ +based on +N2914 +numbering +]

    -
    -

    -In addition, to prevent the infinite recursion that Bo writes about in -his comp.lang.c++.moderated post, I propose to change -27.7.2.4 [ostream::sentry], p2 like so: +

      +
    1. +

      +Just before 27.5.4.2 [basic.ios.members]/2 insert a new paragraph: +

      -

      -
      +
      +Requires: If (tiestr != 0) is true, tiestr must not be reachable +by traversing the linked list of tied stream objects starting from +tiestr->tie(). +
      +
      2. + +
    2. +

      +Change 27.7.2.4 [ostream::sentry]/4 as indicated: +

      + +
      +If ((os.flags() & ios_base::unitbuf) && !uncaught_exception()&& +os.good()) is true, calls os.flush() +os.rdbuf()->pubsync(). If that function returns -1 sets +badbit in os.rdstate() without propagating an exception. +
      +
      3. + +
    -If ((os.flags() & ios_base::unitbuf) && -!uncaught_exception()) is true, -calls os.flush() os.rdbuf()->pubsync(). - @@ -11762,11 +11040,11 @@ calls os.flush() os.rdbuf()->pubsync(). effects of money_base::space and money_base::none on money_get -

    Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: Open - Submitter: Martin Sebor Opened: 2008-05-17 Last modified: 2008-09-22

    +

    Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: Review + Submitter: Martin Sebor Opened: 2008-05-17 Last modified: 2009-07-16

    View other active issues in [locale.money.get.virtuals].

    View all other issues in [locale.money.get.virtuals].

    -

    View all issues with Open status.

    +

    View all issues with Review status.

    Duplicate of: 670

    Discussion:

    @@ -11824,6 +11102,26 @@ San Francisco:
    Martin will revise the proposed resolution.
    + +

    [ +2009-07 Frankfurt: +]

    + + +
    +

    +There is a noun missing from the proposed resolution. It's not clear +that the last sentence would be helpful, even if the word were not +missing: +

    +
    +In either case, any required MISSINGWORD followed by all optional whitespace (as recognized by ct.is()) is consumed. +
    +

    +Strike this sentence and move to Review. +

    +
    +

    Proposed resolution:

    @@ -11846,8 +11144,7 @@ where money_base::space appears in any of the initial elements of the format pattern, at least one white space character is required. Where money_base::none appears in any of the initial elements of the format pattern, white space is allowed but not -required. In either case, any required followed by all optional white -space (as recognized by ct.is()) is consumed. +required. If (str.flags() & str.showbase) is false, ... @@ -11856,150 +11153,14 @@ If (str.flags() & str.showbase) is false, ...
    -

    837. - basic_ios::copyfmt() overly loosely specified -

    -

    Section: 27.5.4.2 [basic.ios.members] Status: Tentatively NAD Editorial - Submitter: Martin Sebor Opened: 2008-05-17 Last modified: 2009-05-23

    -

    View other active issues in [basic.ios.members].

    -

    View all other issues in [basic.ios.members].

    -

    View all issues with Tentatively NAD Editorial status.

    -

    Discussion:

    -

    - -The basic_ios::copyfmt() member function is specified in 27.5.4.2 [basic.ios.members] to have the following effects: - -

    -
    - -Effects: If (this == &rhs) does -nothing. Otherwise assigns to the member objects of *this -the corresponding member objects of rhs, except that - -
      -
    • - -rdstate() and rdbuf() are left unchanged; - -
      • -
    • - -exceptions() is altered last by -calling exceptions(rhs.except) - -
      • -
    • - -the contents of arrays pointed at by pword -and iword are copied not the pointers themselves - -
      • -
    -
    -

    - -Since the rest of the text doesn't specify what the member objects -of basic_ios are this seems a little too loose. - -

    - -

    [ -Batavia (2009-05): -]

    - -
    -We agree with the proposed resolution. -Move to NAD Editorial. -
    - - -

    Proposed resolution:

    -

    - -I propose to tighten things up by adding a Postcondition clause -to the function like so: - -

    -
    - Postconditions: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    copyfmt() postconditions
    ElementValue
    rdbuf()unchanged
    tie()rhs.tie()
    rdstate()unchanged
    exceptions()rhs.exceptions()
    flags()rhs.flags()
    width()rhs.width()
    precision()rhs.precision()
    fill()rhs.fill()
    getloc()rhs.getloc()
    -
    -

    - -The format of the table follows Table 117 (as -of N2588): basic_ios::init() -effects. - -

    -

    - -The intent of the new table is not to impose any new requirements or -change existing ones, just to be more explicit about what I believe is -already there. - -

    - - - - -

    838. can an end-of-stream iterator become a non-end-of-stream one?

    -

    Section: 24.6.1 [istream.iterator] Status: Open - Submitter: Martin Sebor Opened: 2008-05-17 Last modified: 2008-10-27

    +

    Section: 24.6.1 [istream.iterator] Status: Ready + Submitter: Martin Sebor Opened: 2008-05-17 Last modified: 2009-07-16

    View other active issues in [istream.iterator].

    View all other issues in [istream.iterator].

    -

    View all issues with Open status.

    +

    View all issues with Ready status.

    Discussion:

    @@ -12103,6 +11264,16 @@ that no reference is made to exposition only members of

    +

    [ +2009-07 Frankfurt: +]

    + + +
    +Move to Ready. +
    + +

    Proposed resolution:

    @@ -12175,135 +11346,19 @@ return tmp;

    -

    839. Maps and sets missing splice operation

    -

    Section: 23.4 [associative], 23.5 [unord] Status: Open - Submitter: Alan Talbot Opened: 2008-05-18 Last modified: 2008-09-22

    -

    View other active issues in [associative].

    -

    View all other issues in [associative].

    -

    View all issues with Open status.

    +

    847. string exception safety guarantees

    +

    Section: 21.4.1 [string.require] Status: Ready + Submitter: Hervé Brönnimann Opened: 2008-06-05 Last modified: 2009-07-16

    +

    View all other issues in [string.require].

    +

    View all issues with Ready status.

    Discussion:

    -Splice is a very useful feature of list. This functionality is also very -useful for any other node based container, and I frequently wish it were -available for maps and sets. It seems like an omission that these -containers lack this capability. Although the complexity for a splice is -the same as for an insert, the actual time can be much less since the -objects need not be reallocated and copied. When the element objects are -heavy and the compare operations are fast (say a map<int, huge_thingy>) -this can be a big win. -

    - -

    -Suggested resolution: -

    - -

    -Add the following signatures to map, set, multimap, multiset, and the unordered associative containers: -

    -
     
-void splice(list<T,Allocator>&& x);
-void splice(list<T,Allocator>&& x, const_iterator i);
-void splice(list<T,Allocator>&& x, const_iterator first, const_iterator last);
-
    - -

    -Hint versions of these are also useful to the extent hint is useful. -(I'm looking for guidance about whether hints are in fact useful.) -

    - -
     
-void splice(const_iterator position, list<T,Allocator>&& x);
-void splice(const_iterator position, list<T,Allocator>&& x, const_iterator i);
-void splice(const_iterator position, list<T,Allocator>&& x, const_iterator first, const_iterator last);
-
    - -

    [ -Sophia Antipolis: -]

    - - -
    -

    -Don't try to splice "list" into the other containers, it should be container-type. -

    -

    -forward_list already has splice_after. -

    -

    -Would "splice" make sense for an unordered_map? -

    -

    -Jens, Robert: "splice" is not the right term, it implies maintaining ordering in lists. -

    -

    -Howard: adopt? -

    -

    -Jens: absorb? -

    -

    -Alan: subsume? -

    -

    -Robert: recycle? -

    -

    -Howard: transfer? (but no direction) -

    -

    -Jens: transfer_from. No. -

    -

    -Alisdair: Can we give a nothrow guarantee? If your compare() and hash() doesn't throw, yes. -

    -

    -Daniel: For unordered_map, we can't guarantee nothrow. -

    -
    - -

    [ -San Francisco: -]

    - - -
    -

    -Martin: this would possibly outlaw an implementation technique that is -currently in use; caching nodes in containers. -

    -

    -Alan: if you cache in the allocator, rather than the individual -container, this proposal doesn't interfere with that. -

    -

    -Martin: I'm not opposed to this, but I'd like to see an implementation -that demonstrates that it works. -

    -
    - - - -

    Proposed resolution:

    - - - - - -
    -

    847. string exception safety guarantees

    -

    Section: 21.4.1 [string.require] Status: Open - Submitter: Hervé Brönnimann Opened: 2008-06-05 Last modified: 2009-02-14

    -

    View other active issues in [string.require].

    -

    View all other issues in [string.require].

    -

    View all issues with Open status.

    -

    Discussion:

    -

    -In March, on comp.lang.c++.moderated, I asked what were the -string exception safety guarantees are, because I cannot see -*any* in the working paper, and any implementation I know offers -the strong exception safety guarantee (string unchanged if a -member throws exception). The closest the current draft comes to -offering any guarantees is 21.4 [basic.string], para 3: +In March, on comp.lang.c++.moderated, I asked what were the +string exception safety guarantees are, because I cannot see +*any* in the working paper, and any implementation I know offers +the strong exception safety guarantee (string unchanged if a +member throws exception). The closest the current draft comes to +offering any guarantees is 21.4 [basic.string], para 3:

    @@ -12334,7 +11389,7 @@ I take it as saying that this paragraph has *no* implication on std::basic_string, as basic_string isn't defined in Clause 23 and this paragraph does not define a *requirement* of Sequence nor Reversible Container, just of the models defined in Clause 23. -In addition, LWG Issue 718 proposes to remove 23.2 [container.requirements], para 3. +In addition, LWG Issue 718 proposes to remove 23.2 [container.requirements], para 3.

    @@ -12375,6 +11430,15 @@ The proposed resolution of paper interacts with this issue (the paper does not refer to this issue).

    +

    [ +2009-07 Frankfurt: +]

    + + +
    +Move to Ready. +
    +

    Proposed resolution:

    @@ -12407,7 +11471,7 @@ or add paragraphs to Effects clauses wherever appropriate.

    851. simplified array construction

    Section: 23.3.1 [array] Status: Open - Submitter: Benjamin Kosnik Opened: 2008-06-05 Last modified: 2009-06-10

    + Submitter: Benjamin Kosnik Opened: 2008-06-05 Last modified: 2009-07-25

    View other active issues in [array].

    View all other issues in [array].

    View all issues with Open status.

    @@ -12592,7 +11656,7 @@ Add to the array synopsis in 23.3 [sequences]: 

    
 template<ReferentType... Args>
-requires ValueType<C> && Constructible<C, Args&&>...
+requires ValueType<C> && IdentityOf<Args> && Constructible<C, Args&&>...
 array<C, sizeof...(Args)>
 make_array(Args&&... args);
 
@@ -12611,7 +11675,7 @@ the following new section:
 
 
    
 template<ReferentType... Args>
-requires ValueType<C> && Constructible<C, Args&&>...
+requires ValueType<C> && IdentityOf<Args> && Constructible<C, Args&&>...
 array<C, sizeof...(Args)>
 make_array(Args&&... args);
 
    
@@ -12633,151 +11697,87 @@ Let C be decay<common_type<Args...>::type>::type.
    - - -

    Proposed resolution:

    -

    -Add to the array synopsis in 23.3 [sequences]: -

    - -
    template<ValueType T, ValueType... Args>
-  requires Convertible<Args, T>...
-  array<T, sizeof...(Args)> 
-  make_array(Args&&... args);
-
    - -

    -Append after 23.3.1.7 [array.tuple] Tuple interface to class template array the -following new section. -

    - -
    -

    -23.2.1.7 Convenience interface to class template array [array.tuple] -

    - -
    template<ValueType T, ValueType... Args>
-  requires Convertible<Args, T>...
-  array<T, sizeof...(Args)> 
-  make_array(Args&&... args);
-
    - -
    -

    -Returns: an array<T, sizeof...(Args)> initialized with {std::forward<T>(args)...}. -

    -
    -
    - - - - - -
    -

    853. to_string needs updating with zero and one

    -

    Section: 20.3.6 [template.bitset] Status: Tentatively Ready - Submitter: Howard Hinnant Opened: 2008-06-18 Last modified: 2009-05-10

    -

    View other active issues in [template.bitset].

    -

    View all other issues in [template.bitset].

    -

    View all issues with Tentatively Ready status.

    -

    Discussion:

    -

    -Issue 396 adds defaulted arguments to the to_string member, but neglects to update -the three newer to_string overloads. -

    - -

    [ -post San Francisco: -]

    - - -
    -Daniel found problems with the wording and provided fixes. Moved from Ready -to Review. -
    -

    [ -Post Summit: +2009-07 Frankfurt: ]

    -Alisdair: suggest to not repeat the default arguments in B, C, D -(definition of to_string members) -

    -

    -Walter: This is not really a definition. +The proposed resolution uses concepts.

    -Consensus: Add note to the editor: Please apply editor's judgement -whether default arguments should be repeated for B, C, D changes. +Daniel to rewrite the proposed resolution.

    -Recommend Tentatively Ready. +Leave Open.

    [ -2009-05-09: See alternative solution in issue 1113. +2009-07-25 Daniel provides rewritten proposed resolution. ]

    Proposed resolution:

    -
      + +
      1. -

        replace in 20.3.6 [template.bitset]/1 (class bitset) +

        +Add to the array synopsis in 23.3 [sequences]:

        -
        template <class charT, class traits>
-  basic_string<charT, traits, allocator<charT> >
-  to_string(charT zero = charT('0'), charT one = charT('1')) const;
-template <class charT>
-  basic_string<charT, char_traits<charT>, allocator<charT> >
-  to_string(charT zero = charT('0'), charT one = charT('1')) const;
-basic_string<char, char_traits<char>, allocator<char> >
-  to_string(char zero = '0', char one = '1') const;
+
+
        template<class... Args>
+  array<CT, sizeof...(Args)>
+  make_array(Args&&... args);
        2. +

      2. -replace in 20.3.6.2 [bitset.members]/37 +Append after 23.3.1.7 [array.tuple] "Tuple interface to class template array" the +following new section:

        -
        template <class charT, class traits>
-  basic_string<charT, traits, allocator<charT> >
-  to_string(charT zero = charT('0'), charT one = charT('1')) const;
-
        +
        -37 Returns: to_string<charT, traits, allocator<charT> >(zero, one). -
        -
        -
        3. -

      3. -replace in 20.3.6.2 [bitset.members]/38 +XX.X.X.X Array creation functions [array.creation]

        -
        template <class charT>
-  basic_string<charT, char_traits<charT>, allocator<charT> >
-  to_string(charT zero = charT('0'), charT one = charT('1')) const;
-
        -
        -38 Returns: to_string<charT, char_traits<charT>, allocator<charT> >(zero, one). -
        -
        -
        4. +
        
+template<class... Args>
+array<CT, sizeof...(Args)>
+make_array(Args&&... args)
+
        -
      4. +
        +

        +Let CT be decay<common_type<Args...>::type>::type. +

        -replace in 20.3.6.2 [bitset.members]/39 +Returns: An array<CT, sizeof...(Args)> initialized with { +static_cast<CT>(std::forward<Args>(args))... }.

        -
        basic_string<char, char_traits<char>, allocator<char> >
-  to_string(char zero = '0', char one = '1') const;
-
        -
        -39 Returns: to_string<char, char_traits<char>, allocator<char> >(zero, one). +

        +[Example: +

        +
        
+int i = 0; int& ri = i;
+make_array(42u, i, 2.78, ri);
+
        +

        +returns an array of type +

        +
        
+array<double, 4>
+
        + +

        +—end example] +

        5. @@ -12789,10 +11789,12 @@ replace in 20.3.6.2 [bitset.members]/39 + +

        854. default_delete converting constructor underspecified

        -

        Section: 20.8.12.1.1 [unique.ptr.dltr.dflt] Status: Review - Submitter: Howard Hinnant Opened: 2008-06-18 Last modified: 2009-05-23

        +

        Section: 20.8.9.1.1 [unique.ptr.dltr.dflt] Status: Review + Submitter: Howard Hinnant Opened: 2008-06-18 Last modified: 2009-07-26

        View all issues with Review status.

        Discussion:

        @@ -12866,31 +11868,44 @@ Batavia (2009-05): Keep in Review status for the reasons cited. +

        [ +2009-07 Frankfurt: +]

        + -

        Proposed resolution:

        +

        -Change 20.8.12.1.1 [unique.ptr.dltr.dflt]: +The proposed resolution uses concepts. Howard needs to rewrite the +proposed resolution.

        +

        +Move back to Open. +

        +
        + +

        [ +2009-07-26 Howard provided rewritten proposed wording and moved to Review. +]

        -
        namespace std {
-  template <class T> struct default_delete {
-    default_delete();
-    template <class U>
-      requires Convertible<U*, T*>
-      default_delete(const default_delete<U>&);
-    void operator()(T*) const;
-  };
-}
-
        + +

        Proposed resolution:

        -... +Add after 20.8.9.1.1 [unique.ptr.dltr.dflt], p1:

        -
        template <class U>
-  requires Convertible<U*, T*>
-  default_delete(const default_delete<U>& other);
-
        +
        template <class U> default_delete(const default_delete<U>& other);
+
        +
        +

        +-1- Effects: ... +

        +

        +Remarks: This constructor shall participate in overload resolution +if and only if U* is implicitly convertible to T*. +

        +
        +
        @@ -12899,11 +11914,11 @@ Change 20.8.12.1.1 [unique.ptr.dltr.dflt]:

        857. condition_variable::time_wait return bool error prone

        -

        Section: 30.5.1 [thread.condition.condvar] Status: Open - Submitter: Beman Dawes Opened: 2008-06-13 Last modified: 2009-06-14

        +

        Section: 30.5.1 [thread.condition.condvar] Status: Ready + Submitter: Beman Dawes Opened: 2008-06-13 Last modified: 2009-07-16

        View other active issues in [thread.condition.condvar].

        View all other issues in [thread.condition.condvar].

        -

        View all issues with Open status.

        +

        View all issues with Ready status.

        Discussion:

        The meaning of the bool returned by condition_variable::timed_wait is so @@ -12956,6 +11971,16 @@ Howard to provide wording. ]

        +

        [ +2009-07 Frankfurt: +]

        + + +
        +Move to Ready. +
        + +

        Proposed resolution:

        @@ -13269,9 +12294,9 @@ The returned value indicates whether the predicate evaluates to

        859. Monotonic Clock is Conditionally Supported?

        -

        Section: 30.5 [thread.condition] Status: Open - Submitter: Pete Becker Opened: 2008-06-23 Last modified: 2009-06-14

        -

        View all issues with Open status.

        +

        Section: 30.5 [thread.condition] Status: Ready + Submitter: Pete Becker Opened: 2008-06-23 Last modified: 2009-07-21

        +

        View all issues with Ready status.

        Discussion:

        Related to 958, 959.

        @@ -13365,6 +12390,25 @@ are not described in terms of their _until variants. +

        [ +2009-07 Frankfurt: +]

        + + +
        +

        +Beman will send some suggested wording changes to Howard. +

        +

        +Move to Ready. +

        +
        + +

        [ +2009-07-21 Beman added the requested wording changes to 962. +]

        + +

        Proposed resolution:

        @@ -13650,6739 +12694,1055 @@ prior to exiting the function scope.
      5. The loop terminates when pred() returns true or when the time -duration specified by rel_time has elapsed. -
        6. - - - -

        -24 [Note: There is no blocking if pred() is initially true, -even if the timeout has already expired. -- end note] -

        - -

        -Postcondition: lock is locked by the calling thread. -

        - -

        -25 Returns: pred() -

        - -

        -26 [Note: The returned value indicates whether the predicate evaluates to -true regardless of whether the timeout was triggered. -- end note] -

        - -

        -Throws: std::system_error when the effects or postcondition cannot be achieved. -

        - -

        -Error conditions: -

        - -
          -
        • -operation_not_permitted -- if the thread does not own the lock. -
          • -
        • -equivalent error condition from lock.lock() or lock.unlock(). -
          • -
        - - - - - - - - - - -
        -

        860. Floating-Point State

        -

        Section: 26 [numerics] Status: Open - Submitter: Lawrence Crowl Opened: 2008-06-23 Last modified: 2009-03-09

        -

        View other active issues in [numerics].

        -

        View all other issues in [numerics].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -There are a number of functions that affect the floating point state. -These function need to be thread-safe, but I'm unsure of the right -approach in the standard, as we inherit them from C. -

        - -

        [ -San Francisco: -]

        - - -
        -

        -Nick: I think we already say that these functions do not introduce data -races; see 17.6.5.6/20 -

        -

        -Pete: there's more to it than not introducing data races; are these -states maintained per thread? -

        -

        -Howard: 21.5/14 says that strtok and strerror are not required to avoid -data races, and 20.9/2 says the same about asctime, gmtime, ctime, and -gmtime. -

        -

        -Nick: POSIX has a list of not-safe functions. All other functions are -implicitly thread safe. -

        -

        -Lawrence is to form a group between meetings to attack this issue. Nick -and Tom volunteered to work with Lawrence. -

        -

        -Move to Open. -

        -
        - -

        [ -Post Summit: -]

        - - -
        -

        -Hans: Sane oses seem ok. Sensible thing is implementable and makes sense. -

        -

        -Nick: Default wording seems to cover this? Hole in POSIX, these -functions need to be added to list of thread-unsafe functions. -

        -

        -Lawrence: Not sufficient, not "thread-safe" per our definition, but -think of state as a thread-local variable. Need something like "these -functions only affect state in the current thread." -

        -

        -Hans: Suggest the following wording: "The floating point environment is -maintained per-thread." -

        -

        -Walter: Any other examples of state being thread safe that are not -already covered elsewhere? -

        -

        -Have thread unsafe functions paper which needs to be updated. Should -just fold in 26.3 [cfenv] functions. -

        -

        -Recommend Open. Lawrence instead suggests leaving it open until we have -suitable wording that may or may not include the thread local -commentary. -

        -
        - - -

        Proposed resolution:

        -

        -

        - - - - - -
        -

        861. Incomplete specification of EqualityComparable for std::forward_list

        -

        Section: 23.2 [container.requirements] Status: Open - Submitter: Daniel Krügler Opened: 2008-06-24 Last modified: 2008-11-11

        -

        View other active issues in [container.requirements].

        -

        View all other issues in [container.requirements].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -Table 89, Container requirements, defines operator== in terms of the container -member function size() and the algorithm std::equal: -

        - -
        -== is an equivalence relation. a.size() == b.size() && -equal(a.begin(), a.end(), b.begin() -
        - -

        -The new container forward_list does not provide a size member function -by design but does provide operator== and operator!= without specifying it's semantic. -

        -

        -Other parts of the (sequence) container requirements do also depend on -size(), e.g. empty() -or clear(), but this issue explicitly attempts to solve the missing -EqualityComparable specification, -because of the special design choices of forward_list. -

        -

        -I propose to apply one of the following resolutions, which are described as: -

        - -
          -
        1. -Provide a definition, which is optimal for this special container without -previous size test. This choice prevents two O(N) calls of std::distance() -with the corresponding container ranges and instead uses a special -equals implementation which takes two container ranges instead of 1 1/2. -
          2. -
        2. -The simple fix where the usual test is adapted such that size() is replaced -by distance with corresponding performance disadvantages. -
          3. -
        -

        -Both proposal choices are discussed, the preferred choice of the author is -to apply (A). -

        - -

        [ -San Francisco: -]

        - - -
        -

        -There's an Option C: change the requirements table to use distance(). -

        -

        -LWG found Option C acceptable. -

        -

        -Martin will draft the wording for Option C. -

        -
        - -

        [ -post San Francisco: -]

        - - -
        -Martin provided wording for Option C. -
        - - - -

        Proposed resolution:

        -

        -Common part: -

        -
          -
        • -

          -Just betwen 23.3.3.5 [forwardlist.ops] and 23.3.3.6 [forwardlist.spec] -add a new -section "forwardlist comparison operators" [forwardlist.compare] (and -also add the -new section number to 23.3.3 [forwardlist]/2 in front of "Comparison operators"): -

          -
          -forwardlist comparison operators [forwardlist.compare] -
          -
          • -
        - -

        -Option (A): -

        -
        -
          -
        • -

          -Add to the new section [forwardlist.compare] the following paragraphs: -

          - -
          -
          template <class T, class Allocator>
-bool operator==(const forward_list<T,Allocator>& x, const forward_list<T,Allocator>& y);
-
          -
          -

          -Requires: Type T is EqualityComparable ([equalitycomparable]). -

          -

          -Returns: true if -

          -
            -
          • -

            -for every iterator i in the range [x.begin(), E), where E == -x.begin() + M and M == - min(distance(x.begin(), x.end()), distance(y.begin(), y.end())), -the following condition holds: -

            -
            *i == *(y.begin() + (i - x.begin())).
-
            -
            • -
          • -if i == E then i == x.end() && (y.begin() + (i - x.begin())) == y.end(). -
            • -
          • -Otherwise, returns false. -
            • -
          -

          -Throws: Nothing unless an exception is thrown by the equality comparison. -

          -

          -Complexity: At most M comparisons. -

          -
          -
          template <class T, class Allocator>
-bool operator!=(const forward_list<T,Allocator>& x, const forward_list<T,Allocator>& y);
-
          -
          -Returns: !(x == y). -
          -
          -
          • -
        -
        - -

        -Option (B): -

        -
        -
          -
        • -

          -Add to the new section [forwardlist.compare] the following paragraphs: -

          -
          -
          template <class T, class Allocator>
-bool operator==(const forward_list<T,Allocator>& x, const forward_list<T,Allocator>& y);
-
          -
          -

          -Requires: Type T is EqualityComparable ([equalitycomparable]). -

          -

          -Returns: distance(x.begin(), x.end()) == distance(y.begin(), y.end()) -&& equal(x.begin(), x.end(), y.begin()). -

          -
          -
          template <class T, class Allocator>
-bool operator!=(const forward_list<T,Allocator>& x, const forward_list<T,Allocator>& y);
-
          -
          -Returns: !(x == y). -
          -
          -
          • - -
        -
        - -

        -Option (C): -

        -
        -
          -
        • -

          -Change Table 91 - Container Requirements in 23.2.1 [container.requirements.general] -(N2798) like so: -

          - -
            -
          1. -

            -Change the text in the Operational Semantics column in - the row for a == b as follows: -

            -
            -== is an equivalence relation. - distance(a.begin(), a.end()) - a.size() == - distance(b.begin(), b.end()) b.size() && - equal(a.begin(), a.end(), b.begin()) -
            -
            2. - -
          2. -

            -Change the text in the Operational Semantics column in - the row for a.max_size() as follows: -

            -
            -distance(a.begin(), a.end()) - a.size() of the largest possible container -
            -
            3. - -
          3. -

            -Change the text in the Operational Semantics column in - the row for a.empty() as follows: -

            -
            -a.begin() == a.end() - a.size() == 0 -
            -
            4. - -
          4. -

            -In addition, for consistency, change the text in the - Operational Semantics column in the row for a.size() - as follows: -

            -
            -distance(a.begin(), a.end()) - a.end() - a.begin() -
            -
            5. -
          -
          • -
        -
        - - - - - -
        -

        862. Impossible complexity for 'includes'

        -

        Section: 25.5.5.1 [includes] Status: Tentatively NAD Editorial - Submitter: Alisdair Meredith Opened: 2008-07-02 Last modified: 2009-05-23

        -

        View other active issues in [includes].

        -

        View all other issues in [includes].

        -

        View all issues with Tentatively NAD Editorial status.

        -

        Discussion:

        -

        -In 25.5.5.1 [includes] the complexity is "at most -1 comparisons" if passed -two empty ranges. I don't know how to perform a negative number of -comparisions! -

        - -

        -This same issue also applies to: -

        - -
          -
        • set_union
          • -
        • set_intersection
          • -
        • set_difference
          • -
        • set_symmetric_difference
          • -
        • merge
          • -
        - -

        [ -2009-03-30 Beman adds: -]

        - - -
        -Suggest NAD. The complexity of empty ranges is -1 in other places in the -standard. See 25.5.4 [alg.merge] merge and -inplace_merge, and forward_list merge, for example. -The time and effort to find and fix all places in the standard where -empty range[s] result in negative complexity isn't worth the very -limited benefit. -
        - -

        [ -2009-05-09 Alisdair adds: -]

        - - -
        -

        -I'm not happy with NAD if we can find a simple solution. -

        -

        -How about adding a rider somewhere in clause 17 suggesting that complexities -that specify a negative number of operations are treated as specifying zero -operations? That should generically solve the issue without looking for -further cases. -

        -
        - -

        [ -Batavia (2009-05): -]

        - -
        -Pete to provide "straightforward" wording. -Move to NAD Editorial. -
        - - -

        Proposed resolution:

        -

        -Recommend NAD. -

        - - - - - -
        -

        863. What is the state of a stream after close() succeeds

        -

        Section: 27.9.1 [fstreams] Status: Tentatively NAD - Submitter: Steve Clamage Opened: 2008-07-08 Last modified: 2009-05-23

        -

        View all other issues in [fstreams].

        -

        View all issues with Tentatively NAD status.

        -

        Discussion:

        -

        -Suppose writing to an [o]fstream fails and you later close the stream. -The overflow() function is called to flush the buffer (if it exists). -Then the file is unconditionally closed, as if by calling flcose. -

        -

        -If either overflow or fclose fails, close() reports failure, and clearly -the stream should be in a failed or bad state. -

        -

        -Suppose the buffer is empty or non-existent (so that overflow() does not -fail), and fclose succeeds. The close() function reports success, but -what is the state of the stream? -

        - -

        [ -Batavia (2009-05): -]

        - -
        -

        -Tom's impression is that the issue is about the failbit, etc. -

        -

        -Bill responds that the stream is now closed, -and any status bits remain unchanged. -

        -

        -See the description of close() in 27.9.1.17 [fstream.members]. -

        -

        -We prefer not to add wording to say that nothing changes. -Move to NAD. -

        -
        - - -

        Proposed resolution:

        -

        -

        - - - - - -
        -

        865. More algorithms that throw away information

        -

        Section: 25.4.6 [alg.fill], 25.4.7 [alg.generate] Status: Open - Submitter: Daniel Krügler Opened: 2008-07-13 Last modified: 2009-05-23

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -In regard to library defect 488 I found some more algorithms which -unnecessarily throw away information. These are typically algorithms, -which sequentially write into an OutputIterator, but do not return the -final value of this output iterator. These cases are: -

        - -
          -
        1. -
          template<class OutputIterator, class Size, class T>
-void fill_n(OutputIterator first, Size n, const T& value);
          2. - -
        2. -
          template<class OutputIterator, class Size, class Generator>
-void generate_n(OutputIterator first, Size n, Generator gen);
          3. -
        -

        -In both cases the minimum requirements on the iterator are -OutputIterator, which means according to the requirements of -24.2.3 [output.iterators]/2 that only single-pass iterations are guaranteed. -So, if users of fill_n and generate_n have *only* an OutputIterator -available, they have no chance to continue pushing further values -into it, which seems to be a severe limitation to me. -

        - -

        [ -Post Summit Daniel "conceptualized" the wording. -]

        - - -

        [ -Batavia (2009-05): -]

        - -
        -

        -Alisdair likes the idea, but has concerns about the specific wording -about the returns clauses. -

        -

        -Alan notes this is a feature request. -

        -

        -Bill notes we have made similar changes to other algorithms. -

        -

        -Move to Open. -

        -
        - - -

        Proposed resolution:

        -
          -
        1. -

          -Replace the current declaration of fill_n in 25 [algorithms]/2, header -<algorithm> synopsis and in 25.4.6 [alg.fill] by -

          - -
          template<class Iter, IntegralLike Size, class T>
-  requires OutputIterator<Iter, const T&>
-  voidIter fill_n(Iter first, Size n, const T& value);
-
          - -

          -Just after the effects clause p.1 add a new returns clause saying: -

          -
          -Returns: For fill_n and n > Size(0), returns first + n. Otherwise -returns first for fill_n. -
          -
          2. -
        2. -

          -Replace the current declaration of generate_n in 25 [algorithms]/2, header -<algorithm> synopsis and in 25.4.7 [alg.generate] by -

          -
          template<class Iter, IntegralLike Size, Callable Generator>
-  requires OutputIterator<Iter, Generator::result_type>
-        && CopyConstructible<Generator>
-  voidIter generate_n(Iter first, Size n, Generator gen);
-
          -

          -Just after the effects clause p.1 add a new returns clause saying: -

          -
          -Returns: For generate_n and n > Size(0), returns first + n. -Otherwise returns first for generate_n. -
          -
          3. -
        - - - - - -
        -

        867. Valarray and value-initialization

        -

        Section: 26.6.2.1 [valarray.cons] Status: Tentatively NAD Editorial - Submitter: Alberto Ganesh Barbati Opened: 2008-07-20 Last modified: 2009-05-23

        -

        View other active issues in [valarray.cons].

        -

        View all other issues in [valarray.cons].

        -

        View all issues with Tentatively NAD Editorial status.

        -

        Discussion:

        -

        -From 26.6.2.1 [valarray.cons], paragraph 2: -

        - -
        explicit  valarray(size_t);
-
        -
        -The array created by this constructor has a length equal to the value of the argument. The elements -of the array are constructed using the default constructor for the instantiating type T. -
        -
        - -

        -The problem is that the most obvious Ts for valarray are float -and double, they don't have a default constructor. I guess the intent is to value-initialize -the elements, so I suggest replacing: -

        - -
        -The elements of the array are constructed using the default constructor for the instantiating type T. -
        -

        -with -

        -
        -The elements of the array are value-initialized. -
        - -

        -There is another reference to the default constructor of T in the non-normative note in paragraph 9. -That reference should also be replaced. (The normative wording in paragraph 8 refers to T() -and so it doesn't need changes). -

        - -

        [ -Batavia (2009-05): -]

        - -
        -We agree with the proposed resolution. -Move to NAD Editorial. -
        - - -

        Proposed resolution:

        -

        -Change 26.6.2.1 [valarray.cons], paragraph 2: -

        - -
        -
        explicit  valarray(size_t);
-
        -
        -The array created by this constructor has a length equal to the value of the argument. The elements -of the array are constructed using the default constructor for the instantiating type T -value-initialized (8.5 [dcl.init]). -
        -
        - -

        -Change 26.6.2.7 [valarray.members], paragraph 9: -

        - -
        -[Example: If the argument has the value -2, the first two elements of the result will be constructed using the -default constructor -value-initialized (8.5 [dcl.init]); -the third element of the result will be assigned the value of the first element of the argument; etc. -- end example] -
        - - - - - - -
        -

        868. default construction and value-initialization

        -

        Section: 23 [containers] Status: Open - Submitter: Alberto Ganesh Barbati Opened: 2008-07-22 Last modified: 2008-09-22

        -

        View other active issues in [containers].

        -

        View all other issues in [containers].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -The term "default constructed" is often used in wording that predates -the introduction of the concept of value-initialization. In a few such -places the concept of value-initialization is more correct than the -current wording (for example when the type involved can be a built-in) -so a replacement is in order. Two of such places are already covered by -issue 867. This issue deliberately addresses the hopefully -non-controversial changes in the attempt of being approved more quickly. -A few other occurrences (for example in std::tuple, -std::reverse_iterator and std::move_iterator) are left to separate -issues. For std::reverse_iterator, see also issue 408. This issue is -related with issue 724. -

        - -

        [ -San Francisco: -]

        - - -
        -

        -The list provided in the proposed resolution is not complete. James -Dennett will review the library and provide a complete list and will -double-check the vocabulary. -

        -

        -This issue relates to Issue 886 tuple construction -

        -
        - - -

        Proposed resolution:

        -

        -Change X [utility.arg.requirements], paragraph 2: -

        - -
        -In general, a default constructor is not required. Certain container class member function signatures specify -the default constructor -T() -as a default argument. T() shall be a well-defined expression (8.5 [dcl.init]) if one of -those signatures is called using the default argument (8.3.6 [dcl.fct.default]). -
        - -

        -In all the following paragraphs in clause 23 [containers], replace "default constructed" with "value-initialized -(8.5 [dcl.init])": -

        - -
          -
        • 23.3.2.1 [deque.cons] para 2
          • -
        • 23.3.2.2 [deque.capacity] para 1
          • -
        • 23.3.3.1 [forwardlist.cons] para 3
          • -
        • 23.3.3.4 [forwardlist.modifiers] para 21
          • -
        • 23.3.4.1 [list.cons] para 3
          • -
        • 23.3.4.2 [list.capacity] para 1
          • -
        • 23.3.6.1 [vector.cons] para 3
          • -
        • 23.3.6.2 [vector.capacity] para 10
          • -
        - - - - - -
        -

        869. Bucket (local) iterators and iterating past end

        -

        Section: 23.2.5 [unord.req] Status: Tentatively Ready - Submitter: Sohail Somani Opened: 2008-07-22 Last modified: 2009-03-09

        -

        View other active issues in [unord.req].

        -

        View all other issues in [unord.req].

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        -Is there any language in the current draft specifying the behaviour of the following snippet? -

        - -
        unordered_set<int> s;
-unordered_set<int>::local_iterator it = s.end(0);
-
-// Iterate past end - the unspecified part
-it++;
-
        - -

        -I don't think there is anything about s.end(n) being considered an -iterator for the past-the-end value though (I think) it should be. -

        - -

        [ -San Francisco: -]

        - - -
        -We believe that this is not a substantive change, but the proposed -change to the wording is clearer than what we have now. -
        - -

        [ -Post Summit: -]

        - - -
        -Recommend Tentatively Ready. -
        - - - -

        Proposed resolution:

        -

        -Change Table 97 "Unordered associative container requirements" in 23.2.5 [unord.req]: -

        - -
        - - - - - - - - - - - - - - - - - -
        Table 97: Unordered associative container requirements
        expressionreturn typeassertion/note pre/post-conditioncomplexity
        b.begin(n)local_iterator
        const_local_iterator for const b.        		Pre: n shall be in the range [0,b.bucket_count()). Note: [b.begin(n), b.end(n)) is a -valid range containing all of the elements in the nth bucket. -b.begin(n) returns an iterator referring to the first element in the bucket. -If the bucket is empty, then b.begin(n) == b.end(n).Constant
        b.end(n)local_iterator
        const_local_iterator for const b.        		Pre: n shall be in the range [0, b.bucket_count()). -b.end(n) returns an iterator which is the past-the-end value for the bucket.Constant
        -
        - - - - - - -
        -

        873. signed integral type and unsigned integral type are not clearly defined

        -

        Section: 3.9.1 [basic.fundamental] Status: Open - Submitter: Travis Vitek Opened: 2008-06-30 Last modified: 2009-03-21

        -

        View all issues with Open status.

        -

        Discussion:

        -

        - Neither the term "signed integral type" nor the term "unsigned - integral type" is defined in the core language section of the - standard, therefore the library section should avoid its use. The - terms signed integer type and unsigned integer type are - indeed defined (in 3.9.1 [basic.fundamental]), thus the usages should be - replaced accordingly. -

        - -

        - Note that the key issue here is that "signed" + "integral type" != - "signed integral type". - - The types bool, char, char16_t, - char32_t and wchar_t are all listed as - integral types, but are neither of signed integer type or - unsigned integer type. According to 3.9 [basic.types] p7, a synonym for - integral type is integer type. - - Given this, one may choose to assume that an integral type that - can represent values less than zero is a signed integral type. - Unfortunately this can cause ambiguities. - - As an example, if T is unsigned char, the - expression make_signed<T>::type, is supposed to - name a signed integral type. There are potentially two types that - satisfy this requirement, namely signed char and - char (assuming CHAR_MIN < 0). -

        - -

        [ -San Francisco: -]

        - - -
        -Plum, Sebor to review. -
        - -

        [ -Post Summit Daniel adds: -]

        - - -
        -The proposed resolution needs to be "conceptualized". Currently we have -in 14.10.4 [concept.support] only concept IntegralType -for all "integral types", thus indeed the current Container -concept and Iterator concepts are sufficiently satisfied with "integral -types". If the changes are applied, we might ask core for concept -BilateralIntegerType and add proper restrictions to the library -concepts. -
        - - - -

        Proposed resolution:

        -

        - I propose to use the terms "signed integer type" and "unsigned integer - type" in place of "signed integral type" and "unsigned integral type" - to eliminate such ambiguities. -

        - -

        - The proposed change makes it absolutely clear that the difference - between two pointers cannot be char or wchar_t, - but could be any of the signed integer types. - 5.7 [expr.add] paragraph 6... -

        -
        -

        -

          -
        1. - When two pointers to elements of the same array object are - subtracted, the result is the difference of the subscripts of - the two array elements. The type of the result is an - implementation-defined signed integral - typesigned integer type; this type shall be the - same type that is defined as std::ptrdiff_t in the - <cstdint> header (18.1)... -
          2. -
        - -
        - -

        - The proposed change makes it clear that X::size_type and - X::difference_type cannot be char or - wchar_t, but could be one of the signed or unsigned integer - types as appropriate. - X [allocator.requirements] table 40... -

        -
        - Table 40: Allocator requirements - - - - - - - - - - - - - - - - - - - - -
        expressionreturn typeassertion/note/pre/post-condition
        X::size_type - unsigned integral type - unsigned integer type - a type that can represent the size of the largest object in - the allocation model.
        X::difference_type - signed integral type - signed integer type - a type that can represent the difference between any two - pointers in the allocation model.
        -
        - -

        - The proposed change makes it clear that make_signed<T>::type - must be one of the signed integer types as defined in 3.9.1. Ditto for - make_unsigned<T>type and unsigned integer types. - 20.6.6.3 [meta.trans.sign] table 48... -

        -
        - Table 48: Sign modifications - - - - - - - - - - - - - - - - - -
        TemplateComments
        - template <class T> struct make_signed; - - If T names a (possibly cv-qualified) signed - integral typesigned integer type (3.9.1) then - the member typedef type shall name the type - T; otherwise, if T names a (possibly - cv-qualified) unsigned integral typeunsigned - integer type then type shall name the - corresponding signed integral typesigned - integer type, with the same cv-qualifiers as - T; otherwise, type shall name the - signed integral typesigned integer type - with the smallest rank (4.13) for which sizeof(T) == - sizeof(type), with the same cv-qualifiers as - T. - - Requires: T shall be a (possibly - cv-qualified) integral type or enumeration but not a - bool type. -
        - template <class T> struct make_unsigned; - - If T names a (possibly cv-qualified) - unsigned integral typeunsigned integer - type (3.9.1) then the member typedef type - shall name the type T; otherwise, if - T names a (possibly cv-qualified) signed - integral typesigned integer type then - type shall name the corresponding unsigned - integral typeunsigned integer type, with the - same cv-qualifiers as T; otherwise, - type shall name the unsigned integral - typeunsigned integer type with the smallest - rank (4.13) for which sizeof(T) == sizeof(type), - with the same cv-qualifiers as T. - - Requires: T shall be a (possibly - cv-qualified) integral type or enumeration but not a - bool type. -
        -
        - - -

        - Note: I believe that the basefield values should probably be - prefixed with ios_base:: as they are in 22.4.2.2.2 [facet.num.put.virtuals] - - The listed virtuals are all overloaded on signed and unsigned integer - types, the new wording just maintains consistency. - - 22.4.2.1.2 [facet.num.get.virtuals] table 78... -

        -
        - Table 78: Integer Conversions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
        Statestdio equivalent
        basefield == oct%o
        basefield == hex%X
        basefield == 0%i
        signed integral typesigned integer - type%d
        unsigned integral typeunsigned integer - type%u
        -
        - - - -

        - Rationale is same as above. - 22.4.2.2.2 [facet.num.put.virtuals] table 80... -

        -
        - Table 80: Integer Conversions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
        Statestdio equivalent
        basefield == ios_base::oct%o
        (basefield == ios_base::hex) && - !uppercase%x
        (basefield == ios_base::hex)%X
        basefield == 0%i
        for a signed integral typesigned integer - type%d
        for a unsigned integral typeunsigned integer - type%u
        -
        - - -

        - 23.2 [container.requirements] table 80... -

        -
        - Table 89: Container requirements - - - - - - - - - - - - - - - - - - - - - - - - - - -
        expressionreturn typeoperational semanticsassertion/note/pre/post-conditioncomplexity
        X::difference_typesigned integral typesigned integer type is identical to the difference type of X::iterator - and X::const_iteratorcompile time
        X::size_typeunsigned integral typeunsigned integer type size_type can represent any non-negative value of - difference_typecompile time
        -
        - -

        - 24.2 [iterator.concepts] paragraph 1... -

        -
        - Iterators are a generalization of pointers that allow a C++ program to - work with different data structures (containers) in a uniform manner. - To be able to construct template algorithms that work correctly and - efficiently on different types of data structures, the library - formalizes not just the interfaces but also the semantics and - complexity assumptions of iterators. All input iterators - i support the expression *i, resulting in a - value of some class, enumeration, or built-in type T, - called the value type of the iterator. All output iterators - support the expression *i = o where o is a - value of some type that is in the set of types that are - writable to the particular iterator type of i. All - iterators i for which the expression (*i).m - is well-defined, support the expression i->m with the - same semantics as (*i).m. For every iterator type - X for which equality is defined, there is a corresponding - signed integral type signed integer type called - the difference type of the iterator. -
        - -

        - I'm a little unsure of this change. Previously this paragraph would - allow instantiations of linear_congruential_engine on - char, wchar_t, bool, and other types. The - new wording prohibits this. - 26.5.3.1 [rand.eng.lcong] paragraph 2... -

        -
        - The template parameter UIntType shall denote an - unsigned integral typeunsigned integer type - large enough to store values as large as m - 1. If the - template parameter m is 0, the modulus m - used throughout this section 26.4.3.1 is - numeric_limits<result_type>::max() plus 1. [Note: - The result need not be representable as a value of type - result_type. --end note] Otherwise, the following - relations shall hold: a < m and c < - m. -
        - -

        - Same rationale as the previous change. - X [rand.adapt.xor] paragraph 6... -

        -
        - Both Engine1::result_type and - Engine2::result_type shall denote (possibly different) - unsigned integral typesunsigned integer types. - The member result_type shall denote either the type - Engine1::result_type or the type Engine2::result_type, - whichever provides the most storage according to clause 3.9.1. -
        - -

        - 26.5.7.1 [rand.util.seedseq] paragraph 7... -

        -
        - Requires:RandomAccessIterator shall meet the - requirements of a random access iterator (24.1.5) such that - iterator_traits<RandomAccessIterator>::value_type - shall denote an unsigned integral typeunsigned integer - type capable of accomodating 32-bit quantities. -
        - -

        - By making this change, integral types that happen to have a signed - representation, but are not signed integer types, would no longer be - required to use a two's complement representation. This may go against - the original intent, and should be reviewed. - 29.6 [atomics.types.operations] paragraph 24... -

        -
        - Remark: For signed integral typessigned integer - types, arithmetic is defined using two's complement - representation. There are no undefined results. For address types, the - result may be an undefined address, but the operations otherwise have - no undefined behavior. -
        - - - - - - -
        -

        876. basic_string access operations should give stronger guarantees

        -

        Section: 21.4 [basic.string] Status: Open - Submitter: Daniel Krügler Opened: 2008-08-22 Last modified: 2008-09-18

        -

        View other active issues in [basic.string].

        -

        View all other issues in [basic.string].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -During the Sophia Antipolis meeting it was decided to split-off some -parts of the -n2647 -("Concurrency modifications for basic_string") -proposal into a separate issue, because these weren't actually -concurrency-related. The here proposed changes refer to the recent -update document -n2668 -and attempt to take advantage of the -stricter structural requirements. -

        -

        -Indeed there exists some leeway for more guarantees that would be -very useful for programmers, especially if interaction with transactionary -or exception-unaware C API code is important. This would also allow -compilers to take advantage of more performance optimizations, because -more functions can have throw() specifications. This proposal uses the -form of "Throws: Nothing" clauses to reach the same effect, because -there already exists a different issue in progress to clean-up the current -existing "schizophrenia" of the standard in this regard. -

        -

        -Due to earlier support for copy-on-write, we find the following -unnecessary limitations for C++0x: -

        - -
          -
        1. -Missing no-throw guarantees: data() and c_str() simply return -a pointer to their guts, which is a non-failure operation. This should -be spelled out. It is also noteworthy to mention that the same -guarantees should also be given by the size query functions, -because the combination of pointer to content and the length is -typically needed during interaction with low-level API. -
          2. -
        2. -Missing complexity guarantees: data() and c_str() simply return -a pointer to their guts, which is guaranteed O(1). This should be -spelled out. -
          3. -
        3. -Missing reading access to the terminating character: Only the -const overload of operator[] allows reading access to the terminator -char. For more intuitive usage of strings, reading access to this -position should be extended to the non-const case. In contrast -to C++03 this reading access should now be homogeneously -an lvalue access. -
          4. -
        - -

        -The proposed resolution is split into a main part (A) and a -secondary part (B) (earlier called "Adjunct Adjunct Proposal"). -(B) extends (A) by also making access to index position -size() of the at() overloads a no-throw operation. This was -separated, because this part is theoretically observable in -specifically designed test programs. -

        - -

        [ -San Francisco: -]

        - - -
        -

        -We oppose part 1 of the issue but hope to address size() in -issue 877. -

        -

        -We do not support part B. 4 of the issue because of the breaking API change. -

        -

        -We support part A. 2 of the issue. -

        -

        -On support part A. 3 of the issue: -

        -
        -Pete's broader comment: now that we know that basic_string will be a -block of contiguous memory, we should just rewrite its specification -with that in mind. The expression of the specification will be simpler -and probably more correct as a result. -
        -
        - - -

        Proposed resolution:

        -
          -
        1. -
            -
          1. -

            In 21.4.4 [string.capacity], just after p. 1 add a new paragraph: -

            -
            -Throws: Nothing. -
            - -
            2. -
          2. -

            -In 21.4.5 [string.access] replace p. 1 by the following 4 paragraghs: -

            - -
            -

            -Requires: pos ≤ size(). -

            -

            -Returns: If pos < size(), returns *(begin() + pos). Otherwise, returns -a reference to a charT() that shall not be modified. -

            -

            -Throws: Nothing. -

            -

            -Complexity: Constant time. -

            -
            - -
            3. -
          3. -

            -In 21.4.7.1 [string.accessors] replace the now common returns -clause of c_str() and data() by the following three paragraphs: -

            -
            -

            -Returns: A pointer p such that p+i == &operator[](i) for each i -in [0, size()]. -

            -

            -Throws: Nothing. -

            -

            -Complexity: Constant time. -

            -
            -
            4. -
          -
          2. -
        2. -
            -
          1. -

            -In 21.4.5 [string.access] replace p.2 and p.3 by: -

            -
            -

            -Requires: pos ≤ size() -

            -

            -Throws: out_of_range if pos > size(). -

            -
            -
            2. -
          -
          3. -
        - - - - - - -
        -

        877. to throw() or to Throw: Nothing.

        -

        Section: 17 [library] Status: Open - Submitter: Martin Sebor Opened: 2008-08-23 Last modified: 2008-09-18

        -

        View other active issues in [library].

        -

        View all other issues in [library].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        - -Recent changes to -the working -draft have introduced a gratuitous inconsistency with the C++ 2003 -version of the specification with respect to exception guarantees -provided by standard functions. While the C++ 2003 standard -consistenly uses the empty exception specification, throw(), -to declare functions that are guaranteed not to throw exceptions, the -current working draft contains a number of "Throws: Nothing." -clause to specify essentially the same requirement. The difference -between the two approaches is that the former specifies the behavior -of programs that violate the requirement (std::unexpected() -is called) while the latter leaves the behavior undefined. - -

        -

        - -A survey of the working draft reveals that there are a total of 209 -occurrences of throw() in the library portion of the spec, -the majority in clause 18, a couple (literally) in 19, a handful in -20, a bunch in 22, four in 24, one in 27, and about a dozen in D.9. - -

        -

        - -There are also 203 occurrences of "Throws: Nothing." scattered -throughout the spec. - -

        -

        - -While sometimes there are good reasons to use the "Throws: -Nothing." approach rather than making use of throw(), these -reasons do not apply in most of the cases where this new clause has -been introduced and the empty exception specification would be a -better approach. - -

        -

        - -First, functions declared with the empty exception specification -permit compilers to generate better code for calls to such -functions. In some cases, the compiler might even be able to eliminate -whole chunks of user-written code when instantiating a generic -template on a type whose operations invoked from the template -specialization are known not to throw. The prototypical example are -the std::uninitialized_copy() -and std::uninitialized_fill() algorithms where the -entire catch(...) block can be optimized away. - -

        -

        - -For example, given the following definition of -the std::uninitialized_copy function template and a -user-defined type SomeType: - -

        -
        - 
        template <class InputIterator, class ForwardIterator>
-ForwardIterator
-uninitialized_copy (InputIterator first, InputIterator last, ForwardIterator res)
-{
-   typedef iterator_traits<ForwardIterator>::value_type ValueType;
-
-   ForwardIterator start = res;
-
-   try {
-       for (; first != last; ++first, ++res)
-           ::new (&*res) ValueType (*first);
-   }
-   catch (...) {
-       for (; start != res; --start)
-           (&*start)->~ValueType ();
-       throw;
-   }
-   return res;
-}
-
-struct SomeType {
-   SomeType (const SomeType&) throw ();
-}
        -
        -

        - -compilers are able to emit the following efficient specialization -of std::uninitialized_copy<const SomeType*, SomeType*> -(note that the catch block has been optimized away): - -

        -
        - 
        template <> SomeType*
-uninitialized_copy (const SomeType *first, const SomeType *last, SomeType *res)
-{
-   for (; first != last; ++first, ++res)
-       ::new (res) SomeType (*first);
-
-   return res;
-}
        -
        -

        - -Another general example is default constructors which, when decorated -with throw(), allow the compiler to eliminate the -implicit try and catch blocks that it otherwise must -emit around each the invocation of the constructor -in new-expressions. - -

        -

        - -For example, given the following definitions of -class MayThrow and WontThrow and the two -statements below: - -

        -
        - 
        struct MayThrow {
-   MayThrow ();
-};
-
-struct WontThrow {
-   WontThrow () throw ();
-};
-
-MayThrow  *a = new MayThrow [N];
-WontThrow *b = new WontThrow [N];
        - -
        -

        - -the compiler generates the following code for the first statement: - -

        -
        - 
        MayThrow *a;
-{
-   MayThrow *first = operator new[] (N * sizeof (*a));
-   MayThrow *last  = first + N;
-   MayThrow *next  = first;
-   try {
-       for ( ; next != last; ++next)
-           new (next) MayThrow;
-   }
-   catch (...) {
-       for ( ; first != first; --next)
-           next->~MayThrow ();
-       operator delete[] (first);
-       throw;
-   }
-   a = first;
-}
        -
        -

        - -but it is can generate much more compact code for the second statement: - -

        -
        - 
        WontThrow *b    = operator new[] (N * sizeof (*b));
-WontThrow *last = b + N;
-for (WontThrow *next = b; next != last; ++next)
-   new (next) WontThrow;
-
        -
        -

        - -Second, in order for users to get the maximum benefit out of the new -std::has_nothrow_xxx traits when using standard library types -it will be important for implementations to decorate all non throwing -copy constructors and assignment operators with throw(). Note -that while an optimizer may be able to tell whether a function without -an explicit exception specification can throw or not based on its -definition, it can only do so when it can see the source code of the -definition. When it can't it must assume that the function may -throw. To prevent violating the One Definition Rule, -the std::has_nothrow_xxx trait must return the most -pessimistic guess across all translation units in the program, meaning -that std::has_nothrow_xxx<T>::value must evaluate to -false for any T whose xxx -(where xxx is default or copy ctor, or assignment operator) -is defined out-of-line. - -

        -

        - -Counterarguments: - -

        -

        - -During the discussion of this issue -on c++std-lib@accu.org -(starting with post c++std-lib-21950) the following arguments -in favor of the "Throws: Nothing." style have been made. - -

        -

        -

          -
        1. - -Decorating functions that cannot throw with the empty exception -specification can cause the compiler to generate suboptimal code for -the implementation of the function when it calls other functions that -aren't known to the compiler not to throw (i.e., that aren't decorated -with throw() even if they don't actually throw). This is a -common situation when the called function is a C or POSIX function. - -
          2. -
        2. - -Alternate, proprietary mechanisms exist (such as -GCC __attribute__((nothrow)) -or Visual -C++ __declspec(nothrow)) -that let implementers mark up non-throwing functions, often without -the penalty mentioned in (1) above. The C++ standard shouldn't -preclude the use of these potentially more efficient mechanisms. - -
          3. -
        3. - -There are functions, especially function templates, that invoke -user-defined functions that may or may not be -declared throw(). Declaring such functions with the empty -exception specification will cause compilers to generate suboptimal -code when the user-defined function isn't also declared not to throw. - -
          4. -
        - -

        - -The answer to point (1) above is that implementers can (and some have) -declare functions with throw() to indicate to the compiler -that calls to the function can safely be assumed not to throw in order -to allow it to generate efficient code at the call site without also -having to define the functions the same way and causing the compiler -to generate suboptimal code for the function definition. That is, the -function is declared with throw() in a header but it's -defined without it in the source file. The throw() -declaration is suppressed when compiling the definition to avoid -compiler errors. This technique, while strictly speaking no permitted -by the language, is safe and has been employed in practice. For -example, the GNU C library takes this approach. Microsoft Visual C++ -takes a similar approach by simply assuming that no function with C -language linkage can throw an exception unless it's explicitly -declared to do so using the language extension throw(...). - -

        -

        - -Our answer to point (2) above is that there is no existing practice -where C++ Standard Library implementers have opted to make use of the -proprietary mechanisms to declare functions that don't throw. The -language provides a mechanism specifically designed for this -purpose. Avoiding its use in the specification itself in favor of -proprietary mechanisms defeats the purpose of the feature. In -addition, making use of the empty exception specification -inconsistently, in some areas of the standard, while conspicuously -avoiding it and making use of the "Throws: Nothing." form in -others is confusing to users. - -

        -

        - -The answer to point (3) is simply to exercise caution when declaring -functions and especially function templates with the empty exception -specification. Functions that required not to throw but that may call -back into user code are poor candidates for the empty exception -specification and should instead be specified using "Throws: -Nothing." clause. - -

        - -

        Proposed resolution:

        -

        - -We propose two possible solutions. Our recommendation is to adopt -Option 1 below. - -

        -

        - -Option 1: - -

        -

        - -Except for functions or function templates that make calls back to -user-defined functions that may not be declared throw() -replace all occurrences of the "Throws: Nothing." clause with -the empty exception specification. Functions that are required not to -throw but that make calls back to user code should be specified to -"Throw: Nothing." - -

        -

        - -Option 2: - -

        -

        - -For consistency, replace all occurrences of the empty exception -specification with a "Throws: Nothing." clause. - -

        - - - - -
        -

        878. forward_list preconditions

        -

        Section: 23.3.3 [forwardlist] Status: Tentatively Ready - Submitter: Martin Sebor Opened: 2008-08-23 Last modified: 2009-05-10

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        - -forward_list member functions that take -a forward_list::iterator (denoted position in the -function signatures) argument have the following precondition: - -

        -
        - -Requires: position is dereferenceable or equal -to before_begin(). - -
        -

        - -I believe what's actually intended is this: - -

        -
        - -Requires: position is in the range -[before_begin(), end()). - -
        -

        - -That is, when it's dereferenceable, position must point -into *this, not just any forward_list object. - -

        - -

        [ -San Francisco: -]

        - - -
        -Robert suggested alternate proposed wording which had large support. -
        - -

        [ -Post Summit: -]

        - - -
        -

        -Walter: "position is before_begin() or a dereferenceable": add "is" after the "or" -

        -

        -With that minor update, Recommend Tentatively Ready. -

        -
        - - - -

        Proposed resolution:

        -

        - -Change the Requires clauses - [forwardlist] , p21, p24, p26, p29, and, -23.3.3.5 [forwardlist.ops], p39, p43, p47 -as follows: - -

        -
        - -Requires: position is before_begin() or is a -dereferenceable -iterator in the range [begin(), end()) -or equal to before_begin(). ... - -
        - - - - -
        -

        879. Atomic load const qualification

        -

        Section: 29 [atomics] Status: Review - Submitter: Alexander Chemeris Opened: 2008-08-24 Last modified: 2009-03-22

        -

        View other active issues in [atomics].

        -

        View all other issues in [atomics].

        -

        View all issues with Review status.

        -

        Discussion:

        -

        -The atomic_address type and atomic<T*> specialization provide atomic -updates to pointers. However, the current specification requires -that the types pointer be to non-const objects. This restriction -is unnecessary and unintended. -

        - -

        [ -Summit: -]

        - -
        -Move to review. Lawrence will first check with Peter whether the -current examples are sufficient, or whether they need to be expanded to -include all cases. -
        - - -

        Proposed resolution:

        -

        -Add const qualification to the pointer values of the atomic_address -and atomic<T*> specializations. E.g. -

        - -
        typedef struct atomic_address {
-   void store(const void*, memory_order = memory_order_seq_cst) volatile;
-   void* exchange( const void*, memory_order = memory_order_seq_cst) volatile;
-   bool compare_exchange( const void*&, const void*,
-                          memory_order, memory_order) volatile;
-   bool compare_exchange( const void*&, const void*,
-                          memory_order = memory_order_seq_cst ) volatile;
-   void* operator=(const void*) volatile;
-} atomic_address;
-
-void atomic_store(volatile atomic_address*, const void*);
-void atomic_store_explicit(volatile atomic_address*, const void*,
-                          memory_order);
-void* atomic_exchange(volatile atomic_address*, const void*);
-void* atomic_exchange_explicit(volatile atomic_address*, const void*,
-                              memory_order);
-bool atomic_compare_exchange(volatile atomic_address*,
-                            const void**, const void*);
-bool atomic_compare_exchange_explicit(volatile atomic_address*,
-                                     const void**, const void*,
-                                     memory_order, memory_order);
-
        - - - - - -
        -

        880. Missing atomic exchange parameter

        -

        Section: 29 [atomics] Status: Open - Submitter: Lawrence Crowl Opened: 2008-08-24 Last modified: 2009-03-22

        -

        View other active issues in [atomics].

        -

        View all other issues in [atomics].

        -

        View all issues with Open status.

        -

        Duplicate of: 942

        -

        Discussion:

        -

        -The atomic_exchange and atomic_exchange_explicit functions seem to -be inconsistently missing parameters. -

        - -

        [ -Post Summit: -]

        - - -
        -

        -Lawrence: Need to write up a list for Pete with details. -

        -

        -Detlef: Should not be New, we already talked about in Concurrency group. -

        -

        -Recommend Open. -

        -
        - - -

        Proposed resolution:

        -

        -Add the appropriate parameters. For example, -

        - -
        bool atomic_exchange(volatile atomic_bool*, bool);
-bool atomic_exchange_explicit(volatile atomic_bool*, bool, memory_order);
-
        - - - - - -
        -

        881. shared_ptr conversion issue

        -

        Section: 20.8.13.2.1 [util.smartptr.shared.const] Status: Open - Submitter: Peter Dimov Opened: 2008-08-30 Last modified: 2008-09-18

        -

        View other active issues in [util.smartptr.shared.const].

        -

        View all other issues in [util.smartptr.shared.const].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -We've changed shared_ptr<Y> to not convert to shared_ptr<T> when Y* -doesn't convert to T* by resolving issue 687. This only fixed the -converting copy constructor though. -N2351 -later added move support, and -the converting move constructor is not constrained. -

        - -

        [ -San Francisco: -]

        - - -
        -We might be able to move this to NAD, Editorial once shared_ptr is -conceptualized, but we want to revisit this issue to make sure. -
        - - -

        Proposed resolution:

        -

        -We need to change the Requires clause of the move constructor: -

        - -
        shared_ptr(shared_ptr&& r); 
-template<class Y> shared_ptr(shared_ptr<Y>&& r); 
-
        -
        -Requires: For the second constructor Y* shall be -convertible to T*. - -The second constructor shall not participate in overload resolution -unless Y* is convertible to T*. - -
        -
        - -

        -in order to actually make the example in 687 compile -(it now resolves to the move constructor). -

        - - - - - - -
        -

        883. swap circular definition

        -

        Section: 23 [containers] Status: Open - Submitter: Alisdair Meredith Opened: 2008-09-10 Last modified: 2009-03-11

        -

        View other active issues in [containers].

        -

        View all other issues in [containers].

        -

        View all issues with Open status.

        -

        Discussion:

        - -

        -Note in particular that Table 90 "Container Requirements" gives -semantics of a.swap(b) as swap(a,b), yet for all -containers we define swap(a,b) to call a.swap(b) - a -circular definition. -

        - -

        [ -San Francisco: -]

        - - -
        -Robert to propose a resolution along the lines of "Postcondition: "a = -b, b = a" This will be a little tricky for the hash containers, since -they don't have operator==. -
        - -

        [ -Post Summit Anthony Williams provided proposed wording. -]

        - - - - -

        Proposed resolution:

        -

        -In table 80 in section 23.2.1 [container.requirements.general], -replace the postcondition of a.swap(b) with the following: -

        - -
        - - - - - - - - - - - - - - - - - - - - - - - -
        Table 80 -- Container requirements
        ExpressionReturn typeOperational semanticsAssertion/note pre-/post-conidtionComplexity
        ...............
        a.swap(b);void swap(a,b) -Exchange the contents of a and b as-if
        -X u=std::move(a);
        -a=std::move(b);
        -b=std::move(u);        		(Note A)
        -
        - -

        -Remove the reference to swap from the paragraph following the table. -

        - -
        -Notes: the algorithms swap(), equal() and -lexicographical_compare() are defined in Clause 25. ... -
        - - - - - -
        -

        884. shared_ptr swap

        -

        Section: 20.8.13.2.4 [util.smartptr.shared.mod] Status: Tentatively NAD Editorial - Submitter: Jonathan Wakely Opened: 2008-09-15 Last modified: 2009-05-23

        -

        View all issues with Tentatively NAD Editorial status.

        -

        Discussion:

        -
        #include <memory>
-#include <cassert>
-
-struct A { };
-struct B : A { };
-
-int main()
-{
-    std::shared_ptr<A> pa(new A);
-    std::shared_ptr<B> pb(new B);
-    std::swap<A>(pa, pb);  // N.B. no argument deduction
-    assert( pa.get() == pb.get() );
-    return 0;
-}
-
        - -

        -Is this behaviour correct (I believe it is) and if so, is it -unavoidable, or not worth worrying about? -

        - -

        -This calls the lvalue/rvalue swap overload for shared_ptr: -

        - -
        template<class T> void swap( shared_ptr<T> & a, shared_ptr<T> && b );
-
        - -

        -silently converting the second argument from shared_ptr<B> to -shared_ptr<A> and binding the rvalue ref to the produced temporary. -

        - -

        -This is not, in my opinion, a shared_ptr problem; it is a general issue -with the rvalue swap overloads. Do we want to prevent this code from -compiling? If so, how? -

        - -

        -Perhaps we should limit rvalue args to swap to those types that would -benefit from the "swap trick". Or, since we now have shrink_to_fit(), just -eliminate the rvalue swap overloads altogether. The original motivation -was: -

        - -
        vector<A> v = ...;
-...
-swap(v, vector<A>(v));
-
        - -N1690. - -

        [ -Batavia (2009-05): -]

        - -
        -We agree with the proposed resolution. -Move to NAD Editorial. -
        - - -

        Proposed resolution:

        -

        -Recommend NAD Editorial, fixed by -N2844. -

        - - - - - -
        -

        885. pair assignment

        -

        Section: 20.3.3 [pairs] Status: Open - Submitter: Alisdair Meredith Opened: 2008-09-15 Last modified: 2009-05-25

        -

        View other active issues in [pairs].

        -

        View all other issues in [pairs].

        -

        View all issues with Open status.

        -

        Discussion:

        -
        20.2.3 pairs
-Missing assignemnt operator:
-template<class U , class V>
-  requires CopyAssignable<T1, U> && CopyAssignable<T2, V>
-    pair& operator=(pair<U , V> const & p );
-
        - -

        -Well, that's interesting. This assignment operator isn't in the -current working paper, either. Perhaps we deemed it acceptable to -build a temporary of type pair from pair<U, V>, then move-assign -from that temporary? -

        -

        -It sounds more like an issue waiting to be opened, unless you want to plug -it now. As written we risk moving from lvalues. -

        - -

        [ -San Francisco: -]

        - - -
        -

        -Would be NAD if better ctors fixed it. -

        -

        -Related to 811. -

        -
        - -

        [ -post San Francisco: -]

        - - -
        -Possibly NAD Editorial, solved by -N2770. -
        - -

        [ -2009-05-25 Alisdair adds: -]

        - - -
        -Issue 885 was something I reported while reviewing the library concepts -documents ahead of San Francisco. The missing operator was added as part of -the paper adopted at that meeting -(N2770) -and I can confirm this operator is -present in the current working paper. I recommend NAD. -
        - - - -

        Proposed resolution:

        -

        -

        - - - - - -
        -

        886. tuple construction

        -

        Section: 20.5.2.1 [tuple.cnstr] Status: Open - Submitter: Alisdair Meredith Opened: 2008-09-15 Last modified: 2009-05-05

        -

        View other active issues in [tuple.cnstr].

        -

        View all other issues in [tuple.cnstr].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -20.5.2.1 [tuple.cnstr]: -

        -
        -Effects: Default initializes each element. -
        - -

        -Could be clarified to state each "non-trivial" element. Otherwise -we have a conflict with Core deinfition of default initialization - -trivial types do not get initialized (rather than initialization -having no effect) -

        - -

        -I'm going to punt on this one, because it's not an issue that's -related to concepts. I suggest bringing it to Howard's attention on -the reflector. -

        - -

        [ -San Francisco: -]

        - - -
        -

        -Text in draft doesn't mean anything, changing to "non-trivial" makes it -meaningful. -

        -

        -We prefer "value initializes". Present implementations use -value-initialization. Users who don't want value initialization have -alternatives. -

        -

        -Request resolution text from Alisdair. -

        - -

        -This issue relates to Issue 868 default construction and value-initialization. -

        -
        - -

        [ -2009-05-04 Alisdair provided wording and adds: -]

        - - -
        -

        -Note: This IS a change of semantic from TR1, although one the room agreed -with during the discussion. To preserve TR1 semantics, this would have been -worded: -

        -
        requires DefaultConstructible<Types>... tuple();
-
        -
        --2- Effects: Default-initializes each non-trivial element. -
        -
        - - -
        - - -

        Proposed resolution:

        -

        -Change p2 in Construction 20.5.2.1 [tuple.cnstr]: -

        - -
        requires DefaultConstructible<Types>... tuple();
-
        -
        -

        --2- Effects: Default Value-initializes each element. -

        -
        -
        - - - - - - -
        -

        887. issue with condition::wait_...

        -

        Section: 30.5.1 [thread.condition.condvar] Status: Open - Submitter: Lawrence Crowl Opened: 2008-09-15 Last modified: 2009-03-09

        -

        View other active issues in [thread.condition.condvar].

        -

        View all other issues in [thread.condition.condvar].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -The Posix/C++ working group has identified an inconsistency between -Posix and the C++ working draft in that Posix requires the clock to be -identified at creation, whereas C++ permits identifying the clock at the -call to wait. The latter cannot be implemented with the former. -

        - -

        [ -San Francisco: -]

        - - -
        -

        -Howard recommends NAD with the following explanation: -

        - -

        -The intent of the current wording is for the condtion_variable::wait_until -be able to handle user-defined clocks as well as clocks the system knows about. -This can be done by providing overloads for the known clocks, and another -overload for unknown clocks which synchs to a known clock before waiting. -For example: -

        - -
        template <class Duration>
-bool
-condition_variable::wait_until(unique_lock<mutex>& lock,
-                               const chrono::time_point<chrono::system_clock, Duration>& abs_time)
-{
-    using namespace chrono;
-    nanoseconds d = __round_up<nanoseconds>(abs_time.time_since_epoch());
-    __do_timed_wait(lock.mutex()->native_handle(), time_point<system_clock, nanoseconds>(d));
-    return system_clock::now() < abs_time;
-}
-
-template <class Clock, class Duration>
-bool
-condition_variable::wait_until(unique_lock<mutex>& lock,
-                               const chrono::time_point<Clock, Duration>& abs_time)
-{
-    using namespace chrono;
-    typename Clock::time_point  c_entry = Clock::now();
-    system_clock::time_point    s_entry = system_clock::now();
-    nanoseconds dn = __round_up<nanoseconds>(abs_time.time_since_epoch() -
-                                              c_entry.time_since_epoch());
-    __do_timed_wait(lock.mutex()->native_handle(), s_entry + dn);
-    return Clock::now() < abs_time;
-}
-
        - -

        -In the above example, system_clock is the only clock which the underlying -condition variable knows how to deal with. One overload just passes that clock -through. The second overload (approximately) converts the unknown clock into -a system_clock time_point prior to passing it down to the native -condition variable. -

        - -

        -On Posix systems vendors are free to add implementation defined constructors which -take a clock. That clock can be stored in the condition_variable, and converted -to (or not as necessary) as shown above. -

        - -

        -If an implementation defined constructor takes a clock (for example), then part -of the semantics for that implementation defined ctor might include that a -wait_until using a clock other than the one constructed with results -in an error (exceptional condition) instead of a conversion to the stored clock. -Such a design is up to the vendor as once an implementation defined ctor is used, -the vendor is free to specifiy the behavior of waits and/or notifies however -he pleases (when the cv is constructed in an implementation defined manner). -

        -
        - -

        [ -Post Summit: -]

        - - -
        -

        -"POSIX people will review the proposed NAD resolution at their upcoming NY -meeting. -

        - -

        -See the minutes at: http://wiki.dinkumware.com/twiki/bin/view/Posix/POSIX-CppBindingWorkingGroupNewYork2009. -

        -
        - - -

        Proposed resolution:

        -

        -

        - - - - - -
        -

        888. this_thread::yield too strong

        -

        Section: 30.3.2 [thread.thread.this] Status: Tentatively Ready - Submitter: Lawrence Crowl Opened: 2008-09-15 Last modified: 2009-03-09

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        -I never thought I'd say this, but this_thread::yield seems to be too -strong in specification. The issue is that some systems distinguish -between yielding to another thread in the same process and yielding -to another process. Given that the C++ standard only talks about -a single program, one can infer that the specification allows yielding -only to another thread within the same program. Posix has no -facility for that behavior. Can you please file an issue to weaken -the wording. Perhaps "Offers the operating system the opportunity -to reschedule." -

        - -

        [ -Post Summit: -]

        - - -
        -Recommend move to Tentatively Ready. -
        - - - -

        Proposed resolution:

        -

        -Change 30.3.2 [thread.thread.this]/3: -

        - -
        -
        void this_thread::yield();
-
        -
        -Effects: Offers the operating system implementation -the opportunity to reschedule. -another thread. -
        -
        - - - - - -
        -

        889. thread::id comparisons

        -

        Section: 30.3.1.1 [thread.thread.id] Status: Open - Submitter: Lawrence Crowl Opened: 2008-09-15 Last modified: 2009-05-24

        -

        View all other issues in [thread.thread.id].

        -

        View all issues with Open status.

        -

        Discussion:

        - -

        Addresses UK 324

        - -

        -The thread::id type supports the full set of comparison operators. This -is substantially more than is required for the associative containers that -justified them. Please place an issue against the threads library. -

        - -

        [ -San Francisco: -]

        - - -
        -

        -Would depend on proposed extension to POSIX, or non-standard extension. -What about hash? POSIX discussing op. POSIX not known to be considering -support needed for hash, op. -

        -

        -Group expresses support for putting ids in both unordered and ordered containers. -

        -
        - -

        [ -post San Francisco: -]

        - - -
        -

        -Howard: It turns out the current working paper -N2723 -already has hash<thread::id> -(20.7 [function.objects], 20.7.17 [unord.hash]). We simply -overlooked it in the meeting. It is a good thing we voted in favor of it -(again). :-) -

        -

        -Recommend NAD. -

        - -
        - -

        [ -Post Summit: -]

        - - -
        -Recommend to close as NAD. For POSIX, see if we need to add a function to -convert pthread_t to integer. -
        - -

        [ -Post Summit, Alisdair adds: -]

        - - -
        -

        -The recommendation for LWG-889/UK-324 is NAD, already specified. -

        -

        -It is not clear to me that the specification is complete. -

        -

        -In particular, the synopsis of <functional> in 20.7 [function.objects] does not mention hash< thread::id -> nor hash< error_code >, although their -existence is implied by 20.7.17 [unord.hash], p1. -

        -

        -I am fairly uncomfortable putting the declaration for the -thread_id specialization into <functional> as -id is a nested class inside std::thread, so it implies -that <functional> would require the definition of the -thread class template in order to forward declared -thread::id and form this specialization. -

        -

        -It seems better to me that the dependency goes the other way around -(<thread> will more typically make use of -<functional> than vice-versa) and the -hash<thread::id> specialization be declared in the -<thread> header. -

        -

        -I think hash<error_code> could go into either -<system_error> or <functional> and have no -immediate preference either way. However, it should clearly appear in -the synopsis of one of these two. -

        -

        -Recommend moving 889 back to open, and tying in a reference to UK-324. -

        -
        - -

        [ -Batavia (2009-05): -]

        - -
        -Howard observes that thread::id need not be a nested class; -it could be a typedef for a more visible type. -
        - -

        [ -2009-05-24 Alisdair adds: -]

        - -
        -I do not believe this is correct. thread::id is explicitly documents as a -nested class, rather than as an unspecified typedef analogous to an -iterator. If the intent is that this is not implemented as a nested class -(under the as-if freedoms) then this is a novel form of standardese. -
        - - -

        Proposed resolution:

        -

        -Move to NAD. -

        - - - - - -
        -

        890. Improving <system_error> initialization

        -

        Section: 19.5.1 [syserr.errcat] Status: Tentatively Ready - Submitter: Beman Dawes Opened: 2008-09-14 Last modified: 2009-03-09

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        -The static const error_category objects generic_category and -system_category in header <system_error> are currently declared: -

        - -
        const error_category& get_generic_category();
-const error_category& get_system_category();
-
-static const error_category& generic_category = get_generic_category();
-static const error_category& system_category = get_system_category();
-
        - -

        -This formulation has several problems: -

        - -
          -
        • -Implementation details are exposed, since initialization is specified in -the interface. This over-constrains implementations without offsetting -user benefits. The form of initialization specified may be less than -maximally efficient on some platforms. -
          • -
        • -Use of the objects is more expensive in terms of number of machine level -instructions. See Implementation experience below. -
          • -
        • -Depending on the compiler, some cost may be incurred by each translation unit -that includes the header, even if the objects are not used. This is a -common scenario in user code, since the header is included by other -standard library headers. It should be mentioned that at least one -compilers is able to optimize this cost away, however. -
          • -
        - -

        -IO streams uses a somewhat different formulation for iostream_category, but -still suffer much the same problems. -

        - -

        -The original plan was to eliminate these problems by applying the C++0x -constexpr feature. See LWG issue 832. However, that approach turned out -to be unimplementable, since it would require a constexpr object of a -class with virtual functions, and that is not allowed by the core -language. -

        - -

        -The proposed resolution was developed as an alternative. It mitigates the above -problems by removing initialization from the visible interface, allowing -implementations flexibility. -

        - -

        -Implementation experience: -

        - -

        -Prototype implementations of the current WP interface and proposed -resolution interface were tested with recent Codegear, GCC, Intel, and Microsoft -compilers on Windows. The code generated by the Microsoft compiler was studied -at length; the WP and proposal versions generated very similar code. For both versions -the compiler did make use of static -initialization; apparently the compiler applied an implicit constexpr -where useful, even in cases where constexpr would not be permitted by -the language! -

        - -

        -Acknowledgements: -

        - -

        -Martin Sebor, Chris Kohlhoff, and John Lakos provided useful ideas and comments on initialization issues. -

        - -

        [ -San Francisco: -]

        - - -
        -

        -Martin: prefers not to create more file-scope static objects, and would -like to see get_* functions instead. -

        -
        - - -

        [Pre-Summit:]

        - -
        - - -

        -Beman: The proposed resolution has been reworked to remove the file-scope -static objects, per Martin's suggestions. The get_ prefix has been -eliminated from the function names as no longer necessary and to conform with -standard library naming practice. -

        - -
        - -

        [ -Post Summit: -]

        - - -
        -Agreement that this is wise and essential, text provided works and has -been implemented. Seems to be widespread consensus. Move to Tentative Ready. -
        - - - -

        Proposed resolution:

        - -

        Change 17.6.4.12 [value.error.codes] Value of error codes as indicated:

        -
        -

        Certain functions in the C++ standard library report errors via a - std::error_code (19.4.2.2) object. That object's category() member shall - return a reference to std::system_category() for errors originating from the - operating system, or a reference to an implementation-defined error_category - object for errors originating elsewhere. The implementation shall define the - possible values of value() for each of these error categories. [Example: For - operating systems that are based on POSIX, implementations are encouraged to - define the std::system_category() values as identical to the POSIX errno values, - with additional values as defined by the operating system's documentation. - Implementations for operating systems that are not based on POSIX are - encouraged to define values identical to the operating system's values. For - errors that do not originate from the operating system, the implementation may - provide enums for the associated values --end example]

        -
        - -

        -Change 19.5.1.1 [syserr.errcat.overview] Class error_category overview -error_category synopsis as indicated: -

        - -
        -
        const error_category& get_generic_category();
-const error_category& get_system_category();
-
-static storage-class-specifier const error_category& generic_category = get_generic_category();
-static storage-class-specifier const error_category& system_category = get_system_category();
-
        -
        - -

        -Change 19.5.1.5 [syserr.errcat.objects] Error category objects as indicated: -

        - -
        -
        const error_category& get_generic_category();
-
        - -
        - -

        -Returns: A reference to an object of a type derived from class error_category. -

        - -

        -Remarks: The object's default_error_condition and equivalent virtual -functions shall behave as specified for the class error_category. The -object's name virtual function shall return a pointer to the string -"GENERIC". -

        -
        - -
        const error_category& get_system_category();
-
        - -
        -

        -Returns: A reference to an object of a type derived from class error_category. -

        - -

        -Remarks: The object's equivalent virtual functions shall behave as -specified for class error_category. The object's name virtual function -shall return a pointer to the string "system". The object's -default_error_condition virtual function shall behave as follows: -

        -
        -If the argument ev corresponds to a POSIX errno value posv, the function -shall return error_condition(posv, generic_category()). Otherwise, the -function shall return error_condition(ev, system_category()). What -constitutes correspondence for any given operating system is -unspecified. [Note: The number of potential system error codes is large -and unbounded, and some may not correspond to any POSIX errno value. -Thus implementations are given latitude in determining correspondence. --- end note] -
        -
        - -
        - -

        Change 19.5.2.3 [syserr.errcode.constructors] Class error_code constructors -as indicated:

        -
        - 
        error_code();
        -
        -

        Effects: Constructs an object of type error_code.

        -

        Postconditions: val_ == 0 and cat_ == &system_category().

        -
        -
        -

        Change 19.5.2.4 [syserr.errcode.modifiers] Class error_code modifiers as -indicated:

        -
        - 
        void clear();
        -
        -

        Postconditions: value() == 0 and category() == - system_category().

        -
        -
        -

        Change 19.5.2.6 [syserr.errcode.nonmembers] Class error_code non-member -functions as indicated:

        -
        - 
        error_code make_error_code(errc e);
        -
        -

        Returns: error_code(static_cast<int>(e), generic_category()).

        -
        -
        -

        Change 19.5.3.3 [syserr.errcondition.constructors] Class error_condition -constructors as indicated:

        -
        - 
        error_condition();
        -
        -

        Effects: Constructs an object of type error_condition.

        -

        Postconditions: val_ == 0 and cat_ == &generic_category().

        -
        -
        -

        Change 19.5.3.4 [syserr.errcondition.modifiers] Class error_condition -modifiers as indicated:

        -
        - 
        void clear();
        -
        -

        Postconditions: value() == 0 and category() == - generic_category().

        -
        -
        -

        Change 19.5.3.6 [syserr.errcondition.nonmembers] Class error_condition -non-member functions as indicated:

        -
        - 
        error_condition make_error_condition(errc e);
        -
        -

        Returns: error_condition(static_cast<int>(e), generic_category()).

        -
        -
        -

        Change 27.5 [iostreams.base] Iostreams base classes, Header <ios> - synopsis as indicated:

        -
        - 
        concept_map ErrorCodeEnum<io_errc> { };
-error_code make_error_code(io_errc e);
-error_condition make_error_condition(io_errc e);
-storage-class-specifier const error_category& iostream_category();
        -
        -

        Change 27.5.2.1.1 [ios::failure] Class ios_base::failure, paragraph 2 as -indicated:

        -
        -

        When throwing ios_base::failure exceptions, implementations should provide -values of ec that identify the specific reason for the failure. [ Note: Errors -arising from the operating system would typically be reported as -system_category() errors with an error value of the -error number reported by the operating system. Errors arising from within the -stream library would typically be reported as error_code(io_errc::stream, -iostream_category()). --end note ]

        -
        -

        Change 27.5.5.5 [error.reporting] Error reporting as indicated:

        -
        - 
        error_code make_error_code(io_errc e);
        -
        -

        Returns: error_code(static_cast<int>(e), iostream_category()).

        -
        - 
        error_condition make_error_condition(io_errc e);
        -
        -

        Returns: error_condition(static_cast<int>(e), - iostream_category()).

        -
        - 
        storage-class-specifier const error_category& iostream_category();
        -
        -

        The implementation shall initialize iostream_category. Its storage-class-specifier - may be static or extern. It is unspecified whether initialization is static - or dynamic (3.6.2). If initialization is dynamic, it shall occur before - completion of the dynamic initialization of the first translation unit - dynamically initialized that includes header <system_error>.

         -

        -Returns: A reference to an object of a type derived from class error_category. -

        -

        Remarks: The object's default_error_condition and equivalent virtual functions shall -behave as specified for the class error_category. The object's name virtual -function shall return a pointer to the string "iostream".

        -
        -
        - - - - - - - -
        -

        891. std::thread, std::call_once issue

        -

        Section: 30.3.1.2 [thread.thread.constr], 30.4.5.2 [thread.once.callonce] Status: Open - Submitter: Peter Dimov Opened: 2008-09-15 Last modified: 2009-03-22

        -

        View other active issues in [thread.thread.constr].

        -

        View all other issues in [thread.thread.constr].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -I notice that the vararg overloads of std::thread and std::call_once -(N2723 30.3.1.2 [thread.thread.constr] and 30.4.5.2 [thread.once.callonce]) are no longer specified in terms of -std::bind; instead, some of the std::bind wording has been inlined into -the specification. -

        -

        -There are two problems with this. -

        -

        -First, the specification (and implementation) in terms of std::bind allows, for example: -

        - -
        std::thread th( f, 1, std::bind( g ) );
-
        - -

        -which executes f( 1, g() ) in a thread. This can be useful. The -"inlined" formulation changes it to execute f( 1, bind(g) ) in a thread. -

        -

        -Second, assuming that we don't want the above, the specification has copied the wording -

        - -
        -INVOKE(func, w1, w2, ..., wN) (20.6.2) shall be a valid -expression for some values w1, w2, ..., wN -
        - -

        -but this is not needed since we know that our argument list is args; it should simply be -

        - -
        -INVOKE(func, args...) (20.6.2) shall be a valid expression -
        - -

        [ -Summit: -]

        - - -
        -Move to open. -
        - -

        [ -Post Summit Anthony provided proposed wording. -]

        - - - -

        Proposed resolution:

        -

        -Change paragraph 4 of 30.3.1.2 [thread.thread.constr] to: -

        - -
        -
        template <class F> explicit thread(F f);
-template <class F, class ...Args> thread(F&& f, Args&&... args);
-
        -
        --4- Requires: F and each Ti in Args -shall be CopyConstructible if an lvalue and otherwise -MoveConstructible. INVOKE(f, w1, w2, ..., wN args...) -(20.6.2) shall be a valid expression for some values w1, w2, ..., -wN, where N == sizeof...(Args). -
        -
        - -

        -Change paragraph 1 of 30.4.5.2 [thread.once.callonce] to: -

        - -
        template<class Callable, class ...Args> 
-  void call_once(once_flag& flag, Callable func, Args&&... args);
-
        -
        --1- Requires: The template parameters Callable> and each -Ti in Args shall be CopyConstructible if an -lvalue and otherwise MoveConstructible. INVOKE(func, -w1, w2, ..., wN args...) (20.6.2) shall be a -valid expression for some values w1, w2, ..., wN, where -N == sizeof...(Args). -
        -
        - - - - - -
        -

        893. std::mutex issue

        -

        Section: 30.4.1.1 [thread.mutex.class] Status: Open - Submitter: Peter Dimov Opened: 2008-09-15 Last modified: 2009-03-22

        -

        View other active issues in [thread.mutex.class].

        -

        View all other issues in [thread.mutex.class].

        -

        View all issues with Open status.

        -

        Duplicate of: 905

        -

        Discussion:

        -

        -30.4.1.1 [thread.mutex.class]/27 (in -N2723) -says that the behavior is undefined if: -

        -
          -
        • a thread that owns a mutex object calls lock() or -try_lock() on that object
          • -
        -

        -I don't believe that this is right. Calling lock() or try_lock() on a -locked mutex is well defined in the general case. try_lock() is required -to fail and return false. lock() is required to either throw an -exception (and is allowed to do so if it detects deadlock) or to block -until the mutex is free. These general requirements apply regardless of -the current owner of the mutex; they should apply even if it's owned by -the current thread. -

        -

        -Making double lock() undefined behavior probably can be justified (even -though I'd still disagree with the justification), but try_lock() on a -locked mutex must fail. -

        - -

        [ -Summit: -]

        - -
        -

        -Move to open. Proposed resolution: -

        -
          -
        • -In 30.4.1 [thread.mutex.requirements] paragraph 12, change the error -condition for resource_deadlock_would_occur to: "if the implementation -detects that a deadlock would occur" -
          • -
        • -Strike 30.4.1.1 [thread.mutex.class] paragraph 3 bullet 2 "a thread that owns a mutex object -calls lock() or try_lock() on that object, or" -
          • -
        -
        - - -

        Proposed resolution:

        -

        -In 30.4.1 [thread.mutex.requirements] paragraph 12 change: -

        - -
        -
          -
        • ...
          • -
        • -resource_deadlock_would_occur -- if the current thread already owns the mutex and is able -to detect it implementation detects that a deadlock would occur. -
          • -
        • ...
          • -
        -
        - -

        -Strike 30.4.1.1 [thread.mutex.class] paragraph 3 bullet 2: -

        -
        -

        --3- The behavior of a program is undefined if: -

        -
          -
        • ...
          • -
        • -a thread that owns a mutex object calls lock() or try_lock() on that object, or -
          • -
        • ...
          • -
        -
        - - - - - - - -
        -

        895. "Requires:" on std::string::at et al

        -

        Section: 17.5.1.4 [structure.specifications] Status: Open - Submitter: James Dennett Opened: 2008-09-16 Last modified: 2009-03-11

        -

        View other active issues in [structure.specifications].

        -

        View all other issues in [structure.specifications].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -Per discussion, we need an issue open to cover looking at "Requires" -clauses which are not constraints on user code, such as that on -std::basic_string::at. -

        - - -

        Proposed resolution:

        -

        -

        - - - - - -
        -

        896. Library thread safety issue

        -

        Section: 20.8.13.2 [util.smartptr.shared] Status: Open - Submitter: Hans Boehm Opened: 2008-09-16 Last modified: 2008-09-25

        -

        View other active issues in [util.smartptr.shared].

        -

        View all other issues in [util.smartptr.shared].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -It is unclear whether shared_ptr is thread-safe in the sense that -multiple threads may simultaneously copy a shared_ptr. However this -is a critical piece of information for the client, and it has significant -impact on usability for many applications. (Detlef Vollman thinks it -is currently clear that it is not thread-safe. Hans Boehm thinks -it currently requires thread safety, since the use_count is not an -explicit field, and constructors and assignment take a const reference -to an existing shared_ptr.) -

        - -

        -Pro thread-safety: -

        -

        -Many multi-threaded usages are impossible. A thread-safe version can -be used to destroy an object when the last thread drops it, something -that is often required, and for which we have no other easy mechanism. -

        -

        -Against thread-safety: -

        -

        -The thread-safe version is well-known to be far more expensive, even -if used by a single thread. Many applications, including all single-threaded -ones, do not care. -

        - -

        [ -San Francisco: -]

        - - -
        -

        -Beman: this is a complicated issue, and would like to move this to Open -and await comment from Peter Dimov; we need very careful and complete -rationale for any decision we make; let's go slow -

        -

        -Detlef: I think that shared_ptr should not be thread-safe. -

        -

        -Hans: When you create a thread with a lambda, it in some cases makes it -very difficult for the lambda to reference anything in the heap. It's -currently ambiguous as to whether you can use a shared_ptr to get at an -object. -

        -

        -Leave in Open. Detlef will submit an alternative proposed resolution -that makes shared_ptr explicitly unsafe. -

        -

        -A third option is to support both threadsafe and non-safe share_ptrs, -and to let the programmer decide which behavior they want. -

        - -

        -Beman: Peter, do you support the PR? -

        - -

        -Peter: -

        -
        -

        -Yes, I support the proposed resolution, and I certainly oppose any -attempts to make shared_ptr thread-unsafe. -

        -

        -I'd mildly prefer if -

        -
        -[Note: This is true in spite of that fact that such functions often -modify use_count() --end note] -
        -

        -is changed to -

        -
        -[Note: This is true in spite of that fact that such functions often -cause a change in use_count() --end note] -
        -

        -(or something along these lines) to emphasise that use_count() is not, -conceptually, a variable, but a return value. -

        -
        - -
        - - - -

        Proposed resolution:

        -

        -Make it explicitly thread-safe, in this weak sense, as I believe was intended: -

        -

        -Insert in 20.8.13.2 [util.smartptr.shared], before p5: -

        -
        -

        -For purposes of determining the presence of a data race, -member functions do not modify const shared_ptr and -const weak_ptr arguments, nor any objects they -refer to. [Note: This is true in spite of that fact that such functions often -cause a change in use_count() --end note] -

        -
        -

        -On looking at the text, I'm not sure we need a similar disclaimer -anywhere else, since nothing else has the problem with the modified -use_count(). I think Howard arrived at a similar conclusion. -

        - - - - - -
        -

        897. Forward_list issues... Part 2

        -

        Section: 23.3.3.4 [forwardlist.modifiers] Status: Review - Submitter: Howard Hinnant Opened: 2008-09-22 Last modified: 2009-05-23

        -

        View all issues with Review status.

        -

        Discussion:

        -

        -This issue was split off from 892 at the request of the LWG. -

        - -

        [ -San Francisco: -]

        - - -
        -

        -This issue is more complicated than it looks. -

        -

        -paragraph 47: replace each (first, last) with (first, last] -

        -

        -add a statement after paragraph 48 that complexity is O(1) -

        -

        -remove the complexity statement from the first overload of splice_after -

        -

        -We may have the same problems with other modifiers, like erase_after. -Should it require that all iterators in the range (position, last] be -dereferenceable? -

        -
        - -

        -There are actually 3 issues here: -

        - -
          -
        1. -

          -What value should erase_after return? With list, code often -looks like: -

          -
          for (auto i = l.begin(); i != l.end();)
-{
-    // inspect *i and decide if you want to erase it
-    // ...
-    if (I want to erase *i)
-        i = l.erase(i);
-    else
-        ++i;
-}
-
          -

          -I.e. the iterator returned from erase is useful for setting up the -logic for operating on the next element. For forward_list this might -look something like: -

          -
          auto i = fl.before_begin();
-auto ip1 = i;
-for (++ip1; ip1 != fl.end(); ++ip1)
-{
-    // inspect *(i+1) and decide if you want to erase it
-    // ...
-    if (I want to erase *(i+1))
-        i = fl.erase_after(i);
-    else
-        ++i;
-    ip1 = i;
-}
-
          -

          -In the above example code, it is convenient if erase_after returns -the element prior to the erased element (range) instead of the element -after the erase element (range). -

          -

          -Existing practice: -

          -
            -
          • SGI slist returns an iterator referencing the element after the erased range.
            • -
          • CodeWarrior slist returns an iterator referencing the element before the erased range.
            • -
          -

          -There is not a strong technical argument for either solution over the other. -

          -
          2. - -
        2. -

          -With all other containers, operations always work on the range -[first, last) and/or prior to the given position. -

          -

          -With forward_list, operations sometimes work on the range -(first, last] and/or after the given position. -

          -

          -This is simply due to the fact that in order to operate on -*first (with forward_list) one needs access to -*(first-1). And that's not practical with -forward_list. So the operating range needs to start with (first, -not [first (as the current working paper says). -

          -

          -Additionally, if one is interested in splicing the range (first, last), -then (with forward_list), one needs practical (constant time) access to -*(last-1) so that one can set the next field in this node to -the proper value. As this is not possible with forward_list, one must -specify the last element of interest instead of one past the last element of -interest. The syntax for doing this is to pass (first, last] instead -of (first, last). -

          -

          -With erase_after we have a choice of either erasing the range -(first, last] or (first, last). Choosing the latter -enables: -

          -
          x.erase_after(pos, x.end());
-
          - -

          -With the former, the above statement is inconvenient or expensive due to the lack -of constant time access to x.end()-1. However we could introduce: -

          - -
          iterator erase_to_end(const_iterator position);
-
          - -

          -to compensate. -

          - -

          -The advantage of the former ((first, last]) for erase_after -is a consistency with splice_after which uses (first, last] -as the specified range. But this either requires the addition of erase_to_end -or giving up such functionality. -

          - -
          3. - -
        3. -As stated in the discussion of 892, and reienforced by point 2 above, -a splice_after should work on the source range (first, last] -if the operation is to be Ο(1). When splicing an entire list x the -algorithm needs (x.before_begin(), x.end()-1]. Unfortunately x.end()-1 -is not available in constant time unless we specify that it must be. In order to -make x.end()-1 available in constant time, the implementation would have -to dedicate a pointer to it. I believe the design of -N2543 -intended a nominal overhead of foward_list of 1 pointer. Thus splicing -one entire forward_list into another can not be Ο(1). -
          4. -
        - -

        [ -Batavia (2009-05): -]

        - -
        -

        -We agree with the proposed resolution. -

        -

        -Move to Review. -

        -
        - - -

        Proposed resolution:

        -

        -Wording below assumes issue 878 is accepted, but this issue is -independent of that issue. -

        - -

        -Change 23.3.3.4 [forwardlist.modifiers]: -

        - -
        -
        iterator erase_after(const_iterator position);
-
        -
        -

        -Requires: The iterator following position is dereferenceable. -

        -

        -Effects: Erases the element pointed to by the iterator following position. -

        -

        -Returns: An iterator pointing to the element following the one that was erased, or end() if no such -element exists -An iterator equal to position. -

        -
        - - -
        iterator erase_after(const_iterator position, const_iterator last);
-
        -
        -

        -Requires: All iterators in the range -[(position,last) -are dereferenceable. -

        -

        -Effects: Erases the elements in the range -[(position,last). -

        -

        -Returns: An iterator equal to position last -

        -
        -
        - -

        -Change 23.3.3.5 [forwardlist.ops]: -

        - -
        -
        void splice_after(const_iterator position, forward_list<T,Allocator>&& x);
-
        -
        -

        -Requires: position is before_begin() or a -dereferenceable iterator in the range [begin(), end)). &x != this. -

        -

        -Effects: Inserts the contents of x after position, and -x becomes empty. Pointers and references to -the moved elements of x now refer to those same elements but as members of *this. -Iterators referring to the moved elements will continue to refer to their elements, -but they now behave as iterators into *this, not into x. -

        -

        -Throws: Nothing. -

        -

        -Complexity: Ο(1) Ο(distance(x.begin(), x.end())) -

        -
        - -

        ...

        - -
        void splice_after(const_iterator position, forward_list<T,Allocator>&& x, 
-                  const_iterator first, const_iterator last);
-
        -
        -

        -Requires: position is before_begin() or a -dereferenceable iterator in the range [begin(), end)). -(first,last]) is a valid range in -x, and all iterators in the range -(first,last]) are dereferenceable. -position is not an iterator in the range (first,last]). -

        -

        -Effects: Inserts elements in the range (first,last]) -after position and removes the elements from x. -Pointers and references to the moved elements of x now refer to -those same elements but as members of *this. Iterators -referring to the moved elements will continue to refer to their -elements, but they now behave as iterators into *this, not into -x. -

        -

        -Complexity: Ο(1). -

        -
        - -
        - - - - - - -
        -

        898. Small contradiction in n2723 to forward to committee

        -

        Section: 23.3.3.5 [forwardlist.ops] Status: Tentatively Ready - Submitter: Arch Robison Opened: 2008-09-08 Last modified: 2009-05-23

        -

        View other active issues in [forwardlist.ops].

        -

        View all other issues in [forwardlist.ops].

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        -I ran across a small contradiction in working draft n2723. -

        -
        -

        -23.3.3 [forwardlist]p2: A forward_list satisfies all of the -requirements of a container (table 90), except that the size() member -function is not provided. -

        -

        -23.3.3.5 [forwardlist.ops]p57: Complexity: At most size() + x.size() - 1 -comparisons. -

        -
        -

        -Presumably 23.3.3.5 [forwardlist.ops]p57 needs to be rephrased to not use -size(), or note that it is used there only for sake of notational convenience. -

        - -

        [ -2009-03-29 Beman provided proposed wording. -]

        - - -

        [ -Batavia (2009-05): -]

        - -
        -

        -We agree with the proposed resolution. -

        -

        -Move to Tentatively Ready. -

        -
        - - -

        Proposed resolution:

        -

        Change 23.3.3.5 [forwardlist.ops], -forward_list operations, paragraph 19, merge complexity as indicated: -

        -
        Complexity: At most size() + x.size() -distance(begin(), end()) + distance(x.begin(), x.end()) - 1 -comparisons. -
        - - - - - -
        -

        899. Adjusting shared_ptr for nullptr_t

        -

        Section: 20.8.13.2.2 [util.smartptr.shared.dest] Status: Tentatively Ready - Submitter: Peter Dimov Opened: 2008-09-18 Last modified: 2009-05-23

        -

        View all other issues in [util.smartptr.shared.dest].

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        -James Dennett, message c++std-lib-22442: -

        -
        -The wording below addresses one case of this, but opening an -issue to address the need to sanity check uses of the term "pointer" -in 20.8.13.2 [util.smartptr.shared] would be a good thing. -
        -

        -There's one more reference, in ~shared_ptr; we can apply your suggested change to it, too. That is: -

        -

        -Change 20.8.13.2.2 [util.smartptr.shared.dest]/1 second bullet from: -

        -
        -Otherwise, if *this owns a pointer p and a deleter d, d(p) is called. -
        -

        -to: -

        -
        -Otherwise, if *this owns an object p and a deleter d, d(p) is called. -
        - -

        [ -Post Summit: -]

        - - -
        -Recommend Review. -
        - -

        [ -Batavia (2009-05): -]

        - -
        -

        -Peter Dimov notes the analogous change has already been made -to "the new nullptr_t taking constructors -in 20.8.13.2.1 [util.smartptr.shared.const] p9-13." -

        -

        -We agree with the proposed resolution. -Move to Tentatively Ready. -

        -
        - - -

        Proposed resolution:

        -

        -Change 20.8.13.2.2 [util.smartptr.shared.dest]/1 second bullet: -

        -
        -
          -
        • ...
          • -
        • -Otherwise, if *this owns a pointer -an object p and a -deleter d, d(p) is called. -
          • -
        -
        - - - - - -
        -

        900. stream move-assignment

        -

        Section: 27.9.1.8 [ifstream.assign] Status: Open - Submitter: Niels Dekker Opened: 2008-09-20 Last modified: 2009-05-23

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -It -appears that we have an issue similar to issue 675 regarding the move-assignment of -stream types. For example, when assigning to an std::ifstream, -ifstream1, it seems preferable to close the file originally held by -ifstream1: -

        - -
        ifstream1 = std::move(ifstream2); 
-
        - -

        -The current Draft -(N2723) -specifies that the move-assignment of -stream types like ifstream has the same effect as a swap: -

        - -
        -

        -Assign and swap 27.9.1.8 [ifstream.assign] -

        -
        basic_ifstream& operator=(basic_ifstream&& rhs); 
-
        -
        -Effects: swap(rhs). -
        -
        - -

        [ -Batavia (2009-05): -]

        - -
        -

        -Howard agrees with the analysis and the direction proposed. -

        -

        -Move to Open pending specific wording to be supplied by Howard. -

        -
        - - -

        Proposed resolution:

        -

        -

        - - - - - -
        -

        901. insert iterators can move from lvalues

        -

        Section: 24.7.5 [insert.iterator] Status: Tentatively NAD - Submitter: Alisdair Meredith Opened: 2008-09-24 Last modified: 2009-05-23

        -

        View all issues with Tentatively NAD status.

        -

        Discussion:

        -

        Addresses UK 282

        - -

        -The requires clause on the const T & overloads in -back_insert_iterator/front_insert_iterator/insert_iterator mean that the -assignment operator will implicitly move from lvalues of a move-only type. -

        -

        -Suggested resolutions are: -

        -
          -
        1. -Add another overload with a negative constraint on copy-constructible -and flag it "= delete". -
          2. -
        2. -Drop the copy-constructible overload entirely and rely on perfect -forwarding to catch move issues one level deeper. -
          3. -
        3. -This is a fundamental problem in move-syntax that relies on the -presence of two overloads, and we need to look more deeply into this -area as a whole - do not solve this issue in isolation. -
          4. -
        - -

        [ -Post Summit, Alisdair adds: -]

        - - -
        -

        -Both comment and issue have been resolved by the adoption of -N2844 -(rvalue references safety fix) at the last meeting. -

        - -

        -Suggest resolve as NAD Editorial with a reference to the paper. -

        -
        - -

        [ -Batavia (2009-05): -]

        - -
        -We agree that this has been resolved in the latest Working Draft. -Move to NAD. -
        - - -

        Proposed resolution:

        -

        -Recommend NAD, addressed by N2844. -

        - - - - - -
        -

        902. Regular is the wrong concept to constrain numeric_limits

        -

        Section: 18.3.1 [limits] Status: Open - Submitter: Alisdair Meredith Opened: 2008-09-24 Last modified: 2009-03-11

        -

        View all other issues in [limits].

        -

        View all issues with Open status.

        -

        Discussion:

        - -

        Addresses FR 32 and DE 16

        - -

        -numeric_limits has functions specifically designed to return NaNs, which -break the model of Regular (via its axioms.) While floating point types -will be acceptible in many algorithms taking Regular values, it is not -appopriate for this specific API and we need a less refined constraint. -

        - -

        FR 32:

        - -
        -The definition of numeric_limits<> as requiring a regular -type is both conceptually wrong and operationally illogical. As we -pointed before, this mistake needs to be corrected. For example, the -template can be left unconstrained. In fact this reflects a much more -general problem with concept_maps/axioms and their interpretations. It -appears that the current text heavily leans toward experimental academic -type theory. -
        - -

        DE 16:

        - -
        -The class template numeric_limits should not specify the Regular concept -requirement for its template parameter, because it contains functions -returning NaN values for floating-point types; these values violate the -semantics of EqualityComparable. -
        - -

        [ -Summit: -]

        - - -
        -Move to Open. Alisdair and Gaby will work on a solution, along with the new -treatment of axioms in clause 14. -
        - - - -

        Proposed resolution:

        -

        -

        - - - - - -
        -

        903. back_insert_iterator issue

        -

        Section: 24.7.1 [back.insert.iterator] Status: Tentatively NAD - Submitter: Dave Abrahams Opened: 2008-09-19 Last modified: 2009-05-30

        -

        View all issues with Tentatively NAD status.

        -

        Discussion:

        -

        -I just noticed this; don't know how far the problem(?) extends or -whether it's new or existing: back_insert_iterator's operator* is not -const, so you can't dereference a const one. -

        - -

        [ -Post Summit Daniel adds: -]

        - - -
        -

        -If done, this change should be applied for front_insert_iterator, -insert_iterator, ostream_iterator, and ostreambuf_iterator as well. -

        -
        - -

        [ -Batavia (2009-05): -]

        - -
        -

        -Alisdair notes that these all are output iterators. -Howard points out that ++*i -would no longer work if we made this change. -

        -

        -Move to NAD. -

        -
        - -

        [ -2009-05-25 Daniel adds: -]

        - - -
          -
        1. -If 1009 is accepted, OutputIterator does no longer support post increment. -
          2. -
        2. -To support backward compatibility a second overload of operator* -can be added. -Note that the HasDereference concept (and the HasDereference part of concept -Iterator) was specifically refactored to cope with optional const -qualification and -to properly reflect the dual nature of built-in operator* as of -13.5.8 [over.literal]/6. -
          3. -
        - - -

        Proposed resolution:

        - - - - - -
        -

        904. result_of argument types

        -

        Section: 20.7.4 [func.ret] Status: Tentatively Ready - Submitter: Jonathan Wakely Opened: 2008-09-10 Last modified: 2009-03-09

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        -The WP and TR1 have the same text regarding the argument types of a -result_of expression: -

        -
        -The values ti are lvalues when the corresponding type Ti is a -reference type, and rvalues otherwise. -
        -

        -I read this to mean that this compiles: -

        -
        typedef int (*func)(int&);
-result_of<func(int&&)>::type i = 0;
-
        -

        -even though this doesn't: -

        -
        int f(int&);
-f( std::move(0) );
-
        -

        -Should the text be updated to say "when Ti is an lvalue-reference -type" or am I missing something? -

        -

        -I later came up with this self-contained example which won't compile, -but I think it should: -

        -
        struct X {
-  void operator()(int&);
-  int operator()(int&&);
-} x;
-
-std::result_of< X(int&&) >::type i = x(std::move(0));
-
        - -

        [ -Post Summit: -]

        - - -
        -Recommend Tentatively Ready. -
        - - - -

        Proposed resolution:

        -

        -Change 20.7.4 [func.ret], p1: -

        - -
        -... The values ti are lvalues -when the corresponding type Ti is an lvalue-reference type, -and rvalues otherwise. -
        - - - - - -
        -

        906. ObjectType is the wrong concept to constrain initializer_list

        -

        Section: 18.9 [support.initlist] Status: Tentatively Ready - Submitter: Daniel Krügler Opened: 2008-09-26 Last modified: 2009-05-23

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        -The currently proposed constraint on initializer_list's element type -E is that is has to meet ObjectType. This is an underspecification, -because both core language and library part of initializer_list -make clear, that it references an implicitly allocated array: -

        -

        -8.5.4 [dcl.init.list]/4: -

        -
        -When an initializer list is implicitly converted to a -std::initializer_list<E>, the object passed is constructed as if the -implementation allocated an array of N elements of type E, where -N is the number of elements in the initializer list.[..] -
        - -

        -18.9 [support.initlist]/2. -

        - -
        -An object of type initializer_list<E> provides access to an array of -objects of type const E.[..] -
        - -

        -Therefore, E needs to fulfill concept ValueType (thus excluding -abstract class types). This stricter requirement should be added -to prevent deep instantiation errors known from the bad old times, -as shown in the following example: -

        - -
        // Header A: (Should concept-check even in stand-alone modus)
-
-template <DefaultConstructible T>
-requires MoveConstructible<T>
-void generate_and_do_3(T a) {
-  std::initializer_list<T> list{T(), std::move(a), T()};
-  ...
-}
-
-void do_more();
-void do_more_or_less();
-
-template <DefaultConstructible T>
-requires MoveConstructible<T>
-void more_generate_3() {
-  do_more();
-  generate_and_do_3(T());
-}
-
-template <DefaultConstructible T>
-requires MoveConstructible<T>
-void something_and_generate_3() {
-  do_more_or_less();
-  more_generate_3();
-}
-
-// Test.cpp
-
-#include "A.h"
-
-class Abstract {
-public:
-  virtual ~Abstract();
-  virtual void foo() = 0; // abstract type
-  Abstract(Abstract&&){} // MoveConstructible
-  Abstract(){} // DefaultConstructible
-};
-
-int main() {
-  // The restricted template *accepts* the argument, but
-  // causes a deep instantiation error in the internal function
-  // generate_and_do_3:
-  something_and_generate_3<Abstract>();
-}
-
        - -

        -The proposed stricter constraint does not minimize the aim to -support more general containers for which ObjectType would be -sufficient. If such an extended container (lets assume it's still a -class template) provides a constructor that accepts an initializer_list -only this constructor would need to be restricted on ValueType: -

        - -
        template<ObjectType T>
-class ExtContainer {
-public:
-  requires ValueType<T>
-  ExtContainer(std::initializer_list<T>);
-  ...
-};
-
        - -

        [ -Batavia (2009-05): -]

        - -
        -Move to Tentatively Ready. -
        - - - -

        Proposed resolution:

        -
          -
        1. -In 18.9 [support.initlist]/p.1 replace in "header <initializer_list> synopsis" -the constraint "ObjectType" in the template parameter list by the -constraint "ValueType". -
          2. -
        - - - - - - -
        -

        907. Bitset's immutable element retrieval is inconsistently defined

        -

        Section: 20.3.6.2 [bitset.members] Status: Tentatively Ready - Submitter: Daniel Krügler Opened: 2008-09-26 Last modified: 2009-05-23

        -

        View all other issues in [bitset.members].

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        -The current standard 14882::2003(E) as well as the current draft -N2723 -have in common a contradiction of the operational semantics -of member function test 20.3.6.2 [bitset.members]/56-58 and the immutable -member operator[] overload 20.3.6.2 [bitset.members]/64-66 (all references -are defined in terms of -N2723): -

        - -
          -
        1. bool test(size_t pos) const;
-
          -
          -

          -Requires: pos is valid -

          -

          -Throws: out_of_range if pos does not correspond -to a valid bit position. -

          -

          -Returns: true if the bit at position pos in *this -has the value one. -

          -
          -
          2. -
        2. constexpr bool operator[](size_t pos) const;
-
          -
          -

          -Requires: pos shall be valid. -

          -

          -Throws: nothing. -

          -

          -Returns: test(pos). -

          -
          -
          3. -
        - -

        -Three interpretations: -

        - -
          -
        1. -The operator[] overload is indeed allowed to throw an exception -(via test(), if pos corresponds to an invalid bit position) which does -not leave the call frame. In this case this function cannot be a -constexpr function, because test() is not, due to -5.19 [expr.const]/2, last bullet. -
          2. -
        2. -The intend was not to throw an exception in test in case of an -invalid bit position. There is only little evidence for this interpretation. -
          3. -
        3. -The intend was that operator[] should not throw any exception, -but that test has the contract to do so, if the provided bit position -is invalid. -
          4. -
        - -

        -The problem became worse, because issue 720 -recently voted into WP argued that member test logically must be -a constexpr function, because it was used to define the semantics -of another constexpr function (the operator[] overload). -

        - -

        -Three alternatives are proposed, corresponding to the three bullets -(A), (B), and (C), the author suggests to follow proposal (C). -

        - - -Proposed alternatives: - - -
          -
        1. -

          -Remove the constexpr specifier in front of operator[] overload and -undo that of member test (assuming 720 is accepted) in both the -class declaration 20.3.6 [template.bitset]/1 and in the member description -before 20.3.6.2 [bitset.members]/56 and before /64 to read: -

          -
          constexpr bool test(size_t pos) const;
-..
-constexpr bool operator[](size_t pos) const;
-
          - -

          -Change the throws clause of p. 65 to read: -

          - -
          -Throws: nothing -out_of_range if pos does not correspond to a valid bit -position. -
          -
          2. -
        2. -

          -Replace the throws clause p. 57 to read: -

          - -
          -Throws: out_of_range if pos does not correspond to a valid bit -position nothing. -
          -
          3. -
        3. -

          -Undo the addition of the constexpr specifier to the test member -function in both class declaration 20.3.6 [template.bitset]/1 and in the -member description before 20.3.6.2 [bitset.members]/56, assuming that 720 -was applied. -

          - -
          constexpr bool test(size_t pos) const;
-
          - -

          -Change the returns clause p. 66 to read: -

          - -
          -Returns: test(pos) true if the bit at position pos in *this -has the value one, otherwise false. -
          -
          4. -
        - -

        [ -Post Summit: -]

        - - -
        -

        -Lawrence: proposed resolutions A, B, C are mutually exclusive. -

        -

        -Recommend Review with option C. -

        -
        - -

        [ -Batavia (2009-05): -]

        - -
        -We agree with the proposed resolution. -Move to Tentatively Ready. -
        - - -

        Proposed resolution:

        - -
          -
        1. -

          -Undo the addition of the constexpr specifier to the test member -function in both class declaration 20.3.6 [template.bitset]/1 and in the -member description before 20.3.6.2 [bitset.members]/56, assuming that 720 -was applied. -

          - -
          constexpr bool test(size_t pos) const;
-
          - -

          -Change the returns clause p. 66 to read: -

          - -
          -Returns: test(pos) true if the bit at position pos in *this -has the value one, otherwise false. -
          -
          2. -
        - - - - - - -
        -

        908. Deleted assignment operators for atomic types must be volatile

        -

        Section: 29.5 [atomics.types] Status: Open - Submitter: Anthony Williams Opened: 2008-09-26 Last modified: 2009-03-22

        -

        View all other issues in [atomics.types].

        -

        View all issues with Open status.

        -

        Discussion:

        - -

        Addresses US 90

        - -

        -The deleted copy-assignment operators for the atomic types are not -marked as volatile in N2723, whereas the assignment operators from the -associated non-atomic types are. e.g. -

        -
        atomic_bool& operator=(atomic_bool const&) = delete;
-atomic_bool& operator=(bool) volatile;
-
        - -

        -This leads to ambiguity when assigning a non-atomic value to a -non-volatile instance of an atomic type: -

        -
        atomic_bool b;
-b=false;
-
        - -

        -Both assignment operators require a standard conversions: the -copy-assignment operator can use the implicit atomic_bool(bool) -conversion constructor to convert false to an instance of -atomic_bool, or b can undergo a qualification conversion in order to -use the assignment from a plain bool. -

        - -

        -This is only a problem once issue 845 is applied. -

        - -

        [ -Summit: -]

        - -
        -Move to open. Assign to Lawrence. Related to US 90 comment. -
        - - -

        Proposed resolution:

        -

        -Add volatile qualification to the deleted copy-assignment operator of -all the atomic types: -

        - -
        atomic_bool& operator=(atomic_bool const&) volatile = delete;
-atomic_itype& operator=(atomic_itype const&) volatile = delete;
-
        - -

        -etc. -

        -

        -This will mean that the deleted copy-assignment operator will require -two conversions in the above example, and thus be a worse match than -the assignment from plain bool. -

        - - - - - -
        -

        909. regex_token_iterator should use initializer_list

        -

        Section: 28.13.2 [re.tokiter] Status: Tentatively Ready - Submitter: Daniel Krügler Opened: 2008-09-26 Last modified: 2009-05-23

        -

        View all other issues in [re.tokiter].

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        - -

        Addresses UK 319

        -

        -Construction of a regex_token_iterator (28.13.2 [re.tokiter]/6+) usually -requires the provision of a sequence of integer values, which -can currently be done via a std::vector<int> or -a C array of int. Since the introduction of initializer_list in the -standard it seems much more reasonable to provide a -corresponding constructor that accepts an initializer_list<int> -instead. This could be done as a pure addition or one could -even consider replacement. The author suggests the -replacement strategy (A), but provides an alternative additive -proposal (B) as a fall-back, because of the handiness of this -range type: -

        - -

        [ -Batavia (2009-05): -]

        - -
        -We strongly recommend alternative B of the proposed resolution -in order that existing code not be broken. -With that understanding, move to Tentatively Ready. -
        - -

        Original proposed wording:

        - -
          -

        1. -
            -
          1. -

            -In 28.13.2 [re.tokiter]/6 and the list 28.13.2.1 [re.tokiter.cnstr]/10-11 change the -constructor declaration: -

            - -
            template <std::size_t N>
-regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
-                     const regex_type& re,
-                     const int (&submatches)[N] initializer_list<int> submatches,
-                     regex_constants::match_flag_type m =
-                       regex_constants::match_default);
-
            -
            2. - -
          2. -

            -In 28.13.2.1 [re.tokiter.cnstr]/12 change the last sentence -

            - -
            -The third constructor initializes the member subs to hold -a copy of the sequence of integer values pointed to by the -iterator range [&submatches.begin(), -&submatches.end() + N). -
            -
            3. -
          -
          2. - -

        2. -
            -
          1. -

            -In 28.13.2 [re.tokiter]/6 and the list 28.13.2.1 [re.tokiter.cnstr]/10-11 insert the -following constructor declaration between the already existing ones -accepting a std::vector and a C array of int, resp.: -

            - -
            regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
-                     const regex_type& re,
-                     initializer_list<int> submatches,
-                     regex_constants::match_flag_type m =
-                       regex_constants::match_default);
-
            -
            2. -
          2. -

            -In 28.13.2.1 [re.tokiter.cnstr]/12 change the last sentence -

            - -
            -The third and fourth constructor initializes the member subs -to hold a copy of the sequence of integer values pointed to -by the iterator range [&submatches,&submatches + N) -and [submatches.begin(),submatches.end()), respectively. -
            -
            3. -
          -
          3. - -
        - - - -

        Proposed resolution:

        - -
          - -

        1. -
            -
          1. -

            -In 28.13.2 [re.tokiter]/6 and the list 28.13.2.1 [re.tokiter.cnstr]/10-11 insert the -following constructor declaration between the already existing ones -accepting a std::vector and a C array of int, resp.: -

            - -
            regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
-                     const regex_type& re,
-                     initializer_list<int> submatches,
-                     regex_constants::match_flag_type m =
-                       regex_constants::match_default);
-
            -
            2. -
          2. -

            -In 28.13.2.1 [re.tokiter.cnstr]/12 change the last sentence -

            - -
            -The third and fourth constructor initializes the member subs -to hold a copy of the sequence of integer values pointed to -by the iterator range [&submatches,&submatches + N) -and [submatches.begin(),submatches.end()), respectively. -
            -
            3. -
          -
          2. - -
        - - - - - - -
        -

        910. Effects of MoveAssignable

        -

        Section: 20.2.9 [concept.copymove] Status: Tentatively Ready - Submitter: Alberto Ganesh Barbati Opened: 2008-09-29 Last modified: 2009-05-23

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        Addresses UK 150

        - -

        -The description of the effect of operator= in the MoveAssignable -concept, given in paragraph 7 is: -

        - -
        result_type  T::operator=(T&&  rv);  // inherited from HasAssign<T, T&&>
-
        - -
        -Postconditions: the constructed T object is equivalent to the value of -rv before the assignment. [Note: there is no -requirement on the value of rv after the assignment. --end note] -
        -
        - -

        -The sentence contains a typo (what is the "constructed T object"?) -probably due to a cut&paste from MoveConstructible. Moreover, the -discussion of LWG issue 675 shows that the postcondition is too generic -and might not reflect the user expectations. An implementation of the -move assignment that just calls swap() would always fulfill the -postcondition as stated, but might have surprising side-effects in case -the source rvalue refers to an object that is not going to be -immediately destroyed. See LWG issue 900 for another example. Due to -the sometimes intangible nature of the "user expectation", it seems -difficult to have precise normative wording that could cover all cases -without introducing unnecessary restrictions. However a non-normative -clarification could be a very helpful warning sign that swapping is not -always the correct thing to do. -

        - -

        [ -2009-05-09 Alisdair adds: -]

        - - -
        -

        -Issue 910 is exactly the reason BSI advanced the Editorial comment UK-150. -

        -

        -The post-conditions after assignment are at a minimum that the object -referenced by rv must be safely destructible, and the transaction should not -leak resources. Ideally it should be possible to simply assign rv a new -valid state after the call without invoking undefined behaviour, but any -other use of the referenced object would depend upon additional guarantees -made by that type. -

        -
        - -

        [ -2009-05-09 Howard adds: -]

        - - -
        -

        -The intent of the rvalue reference work is that the moved from rv is -a valid object. Not one in a singular state. If, for example, the moved from -object is a vector, one should be able to do anything on that moved-from -vector that you can do with any other vector. However you would -first have to query it to find out what its current state is. E.g. it might have capacity, -it might not. It might have a non-zero size, it might not. But regardless, -you can push_back on to it if you want. -

        - -

        -That being said, most standard code is now conceptized. That is, the concepts -list the only operations that can be done with templated types - whether or not -the values have been moved from. -

        - -

        -Here is user-written code which must be allowed to be legal: -

        -
        #include <vector>
-#include <cstdio>
-
-template <class Allocator>
-void
-inspect(std::vector<double, Allocator>&& v)
-{
-    std::vector<double, Allocator> result(move(v));
-    std::printf("moved from vector has %u size and %u capacity\n", v.size(), v.capacity());
-    std::printf("The contents of the vector are:\n");
-    typedef typename std::vector<double, Allocator>::iterator I;
-    for (I i = v.begin(), e = v.end(); i != e; ++i)
-        printf("%f\n", *i);
-}
-
-int main()
-{
-    std::vector<double> v1(100, 5.5);
-    inspect(move(v1));
-}
-
        - -

        -The above program does not treat the moved-from vector as singular. It -only treats it as a vector with an unknown value. -

        -

        -I believe the current proposed wording is consistent with my view on this. -

        -
        - -

        [ -Batavia (2009-05): -]

        - -
        -We agree that the proposed resolution -is an improvement over the current wording. -
        - - - -

        Proposed resolution:

        -

        -In 20.2.9 [concept.copymove], replace the postcondition in paragraph 7 with: -

        - -
        -Postconditions: *this is equivalent to the value of rv before the -assignment. [Note: there is no requirement on the value of rv after the -assignment, but the -effect should be unsurprising to the user even in case rv is not -immediately destroyed. This may require that resources previously owned -by *this are released instead of transferred to rv. -- end note] -
        - - - - - -
        -

        911. I/O streams and move/swap semantic

        -

        Section: 27.7.1 [input.streams], 27.7.2 [output.streams] Status: Open - Submitter: Alberto Ganesh Barbati Opened: 2008-09-29 Last modified: 2009-05-23

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -Class template basic_istream, basic_ostream and basic_iostream -implements public move constructors, move assignment operators and swap -method and free functions. This might induce both the user and the -compiler to think that those types are MoveConstructible, MoveAssignable -and Swappable. However, those class templates fail to fulfill the user -expectations. For example: -

        - -
        std::ostream os(std::ofstream("file.txt"));
-assert(os.rdbuf() == 0); // buffer object is not moved to os, file.txt has been closed
-
-std::vector<std::ostream> v;
-v.push_back(std::ofstream("file.txt"));
-v.reserve(100); // causes reallocation
-assert(v[0].rdbuf() == 0); // file.txt has been closed!
-
-std::ostream&& os1 = std::ofstream("file1.txt");
-os1 = std::ofstream("file2.txt");
-os1 << "hello, world"; // still writes to file1.txt, not to file2.txt!
-
-std::ostream&& os1 = std::ofstream("file1.txt");
-std::ostream&& os2 = std::ofstream("file2.txt");
-std::swap(os1, os2);
-os1 << "hello, world"; // writes to file1.txt, not to file2.txt!
-
        - -

        -This is because the move constructor, the move assignment operator and -swap are all implemented through calls to std::basic_ios member -functions move() and swap() that do not move nor swap the controlled -stream buffers. That can't happen because the stream buffers may have -different types. -

        - -

        -Notice that for basic_streambuf, the member function swap() is -protected. I believe that is correct and all of basic_istream, -basic_ostream, basic_iostream should do the same as the move ctor, move -assignment operator and swap member function are needed by the derived -fstreams and stringstreams template. The free swap functions for -basic_(i|o|io)stream templates should be removed for the same reason. -

        - -

        [ -Batavia (2009-05): -]

        - -
        -

        -We note that the rvalue swap functions have already been removed. -

        -

        -Bill is unsure about making the affected functions protected; -he believes they may need to be public. -

        -

        -We are also unsure about removing the lvalue swap functions as proposed. -

        -

        -Move to Open. -

        -
        - - -

        Proposed resolution:

        -

        -27.7.1.1 [istream]: make the following member functions protected: -

        - -
        basic_istream(basic_istream&&  rhs);
-basic_istream&  operator=(basic_istream&&  rhs);
-void  swap(basic_istream&&  rhs);
-
        - -

        -Ditto: remove the three swap free functions signatures -

        - -
        // swap: 
-template <class charT, class traits> 
-  void swap(basic_istream<charT, traits>& x, basic_istream<charT, traits>& y); 
-template <class charT, class traits> 
-  void swap(basic_istream<charT, traits>&& x, basic_istream<charT, traits>& y); 
-template <class charT, class traits> 
-  void swap(basic_istream<charT, traits>& x, basic_istream<charT, traits>&& y);
-
        - -

        -27.7.1.1.2 [istream.assign]: remove paragraph 4 -

        - -
        template <class charT, class traits> 
-  void swap(basic_istream<charT, traits>& x, basic_istream<charT, traits>& y); 
-template <class charT, class traits> 
-  void swap(basic_istream<charT, traits>&& x, basic_istream<charT, traits>& y); 
-template <class charT, class traits> 
-  void swap(basic_istream<charT, traits>& x, basic_istream<charT, traits>&& y);
-
        -
        -Effects: x.swap(y). -
        -
        - -

        -27.7.1.5 [iostreamclass]: make the following member function protected: -

        - -
        basic_iostream(basic_iostream&&  rhs);
-basic_iostream&  operator=(basic_iostream&&  rhs);
-void  swap(basic_iostream&&  rhs);
-
        - -

        -Ditto: remove the three swap free functions signatures -

        - -
        template <class charT, class traits> 
-  void swap(basic_iostream<charT, traits>& x, basic_iostream<charT, traits>& y); 
-template <class charT, class traits> 
-  void swap(basic_iostream<charT, traits>&& x, basic_iostream<charT, traits>& y); 
-template <class charT, class traits> 
-  void swap(basic_iostream<charT, traits>& x, basic_iostream<charT, traits>&& y);
-
        - -

        -27.7.1.5.3 [iostream.assign]: remove paragraph 3 -

        - -
        template <class charT, class traits> 
-  void swap(basic_iostream<charT, traits>& x, basic_iostream<charT, traits>& y); 
-template <class charT, class traits> 
-  void swap(basic_iostream<charT, traits>&& x, basic_iostream<charT, traits>& y); 
-template <class charT, class traits> 
-  void swap(basic_iostream<charT, traits>& x, basic_iostream<charT, traits>&& y);
-
        -
        -Effects: x.swap(y). -
        -
        - -

        -27.7.2.1 [ostream]: make the following member function protected: -

        - -
        basic_ostream(basic_ostream&&  rhs);
-basic_ostream&  operator=(basic_ostream&&  rhs);
-void  swap(basic_ostream&&  rhs);
-
        - -

        -Ditto: remove the three swap free functions signatures -

        - -
        // swap: 
-template <class charT, class traits> 
-  void swap(basic_ostream<charT, traits>& x, basic_ostream<charT, traits>& y);
-template <class charT, class traits> 
-  void swap(basic_ostream<charT, traits>&& x, basic_ostream<charT, traits>& y); 
-template <class charT, class traits> 
-  void swap(basic_ostream<charT, traits>& x, basic_ostream<charT, traits>&& y);
-
        - -

        -27.7.2.3 [ostream.assign]: remove paragraph 13 (The paragraphs seems to -be misnumbered in the whole section 27.7.2 [output.streams] in -N2723. -The paragraph to -remove is the one that describes the three swap free functions). -

        - -
        template <class charT, class traits> 
-  void swap(basic_ostream<charT, traits>& x, basic_ostream<charT, traits>& y); 
-template <class charT, class traits> 
-  void swap(basic_ostream<charT, traits>&& x, basic_ostream<charT, traits>& y); 
-template <class charT, class traits> 
-  void swap(basic_ostream<charT, traits>& x, basic_ostream<charT, traits>&& y);
-
        -
        -Effects: x.swap(y). -
        -
        - - - - - - -
        -

        912. Array swap needs to be conceptualized

        -

        Section: 25.4.3 [alg.swap] Status: Tentatively NAD - Submitter: Daniel Krügler Opened: 2008-10-01 Last modified: 2009-05-23

        -

        View all other issues in [alg.swap].

        -

        View all issues with Tentatively NAD status.

        -

        Discussion:

        -

        -With the adaption of 809 -we have a new algorithm swap for C-arrays, which needs to be conceptualized. -

        - -

        [ -Post Summit Daniel adds: -]

        - - -
        -Recommend as NAD Editorial: The changes have already been applied to the WP -N2800. -
        - -

        [ -Batavia (2009-05): -]

        - -
        -Move to NAD; the changes have already been made. -
        - - -

        Proposed resolution:

        -

        -Replace in 25.4.3 [alg.swap] before p. 3 until p. 4 by -

        - -
        template <class ValueType T, size_t N>
-requires Swappable<T>
-void swap(T (&a)[N], T (&b)[N]);
-
        -
        -

        -Requires: T shall be Swappable. -

        -

        -Effects: swap_ranges(a, a + N, b); -

        -
        -
        - - - - - - -
        -

        913. Superfluous requirements for replace algorithms

        -

        Section: 25.4.5 [alg.replace] Status: Tentatively Ready - Submitter: Daniel Krügler Opened: 2008-10-03 Last modified: 2009-05-23

        -

        View other active issues in [alg.replace].

        -

        View all other issues in [alg.replace].

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        -(A) 25.4.5 [alg.replace]/1: -

        - -
        -Requires: The expression *first = new_value shall be valid. -
        - -

        -(B) 25.4.5 [alg.replace]/4: -

        - -
        -Requires: The results of the expressions *first and new_value shall -be writable to the result output iterator.[..] -
        - -

        -Since conceptualization, the quoted content of these clauses is covered -by the existing requirements -

        - -

        -(A) OutputIterator<Iter, const T&> -

        - -

        -and -

        - -

        -(B) OutputIterator<OutIter, InIter::reference> && OutputIterator<OutIter, const T&> -

        - -

        -resp, and thus should be removed. -

        - -

        [ -Batavia (2009-05): -]

        - -
        -

        -We agree with the proposed resolution. -

        -

        -Move to Tentatively Ready. -

        -
        - - -

        Proposed resolution:

        -
          -
        1. -

          -Remove 25.4.5 [alg.replace]/1. -

          -
          template<ForwardIterator Iter, class T> 
-  requires OutputIterator<Iter, Iter::reference> 
-        && OutputIterator<Iter, const T&> 
-        && HasEqualTo<Iter::value_type, T> 
-  void replace(Iter first, Iter last, 
-               const T& old_value, const T& new_value); 
-
-template<ForwardIterator Iter, Predicate<auto, Iter::value_type> Pred, class T> 
-  requires OutputIterator<Iter, Iter::reference> 
-        && OutputIterator<Iter, const T&> 
-        && CopyConstructible<Pred> 
-  void replace_if(Iter first, Iter last, 
-                  Pred pred, const T& new_value);
-
          -
          -1 Requires: The expression *first = new_value shall be valid. -
          -
          -
          2. -
        2. -

          -25.4.5 [alg.replace]/4: Remove the sentence "The results of the -expressions *first and -new_value shall be writable to the result output iterator.". -

          -
          template<InputIterator InIter, typename OutIter, class T> 
-  requires OutputIterator<OutIter, InIter::reference> 
-        && OutputIterator<OutIter, const T&> 
-        && HasEqualTo<InIter::value_type, T> 
-  OutIter replace_copy(InIter first, InIter last, 
-                       OutIter result, 
-                       const T& old_value, const T& new_value);
-
-template<InputIterator InIter, typename OutIter,
-         Predicate<auto, InIter::value_type> Pred, class T> 
-  requires OutputIterator<OutIter, InIter::reference> 
-        && OutputIterator<OutIter, const T&> 
-        && CopyConstructible<Pred> 
-  OutIter replace_copy_if(InIter first, InIter last, 
-                          OutIter result, 
-                          Pred pred, const T& new_value);
-
          -
          -4 Requires: The results of the expressions *first and -new_value shall be writable to the result output -iterator. The ranges [first,last) and [result,result + -(last - first)) shall not overlap. -
          -
          -
          3. -
        - - - - - -
        -

        914. Superfluous requirement for unique

        -

        Section: 25.4.9 [alg.unique] Status: Tentatively Ready - Submitter: Daniel Krügler Opened: 2008-10-03 Last modified: 2009-05-23

        -

        View other active issues in [alg.unique].

        -

        View all other issues in [alg.unique].

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        -25.4.9 [alg.unique]/2: "Requires: The comparison function shall be an -equivalence relation." -

        - -

        -The essence of this is already covered by the given requirement -

        - -
        EquivalenceRelation<auto, Iter::value_type> Pred
-
        - -

        -and should thus be removed. -

        - -

        [ -Batavia (2009-05): -]

        - -
        -We agree with the proposed resolution. -Move to Tentatively Ready. -
        - - -

        Proposed resolution:

        -

        -Remove 25.4.9 [alg.unique]/2 -

        - -
        template<ForwardIterator Iter>
-  requires OutputIterator<Iter, Iter::reference>
-        && EqualityComparable<Iter::value_type>
-  Iter unique(Iter first, Iter last);
-
-template<ForwardIterator Iter, EquivalenceRelation<auto, Iter::value_type> Pred>
-  requires OutputIterator<Iter, RvalueOf<Iter::reference>::type>
-        && CopyConstructible<Pred>
-  Iter unique(Iter first, Iter last,
-               Pred pred);
-
        -
        -

        -1 Effects: ... -

        -

        -2 Requires: The comparison function shall be an equivalence relation. -

        -
        -
        - - - - - -
        -

        915. minmax with initializer_list should return -pair of T, not pair of const T&

        -

        Section: 25.5.7 [alg.min.max] Status: Tentatively Ready - Submitter: Daniel Krügler Opened: 2008-10-04 Last modified: 2009-05-23

        -

        View other active issues in [alg.min.max].

        -

        View all other issues in [alg.min.max].

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        -It seems that the proposed changes for -N2772 -were not clear enough in -this point: -

        - -
        -25.5.7 [alg.min.max], before p.23 + p.24 + before p. 27 + p. 28 say that the return -type of the minmax overloads with an initializer_list is -pair<const T&, const T&>, -which is inconsistent with the decision for the other min/max overloads which take -a initializer_list as argument and return a T, not a const T&. -Doing otherwise for minmax would easily lead to unexpected life-time -problems by using minmax instead of min and max separately. -
        - -

        [ -Batavia (2009-05): -]

        - -
        -We agree with the proposed resolution. -Move to Tentatively Ready. -
        - - -

        Proposed resolution:

        -
          -
        1. -

          -In 25 [algorithms]/2, header <algorithm> synopsis change as indicated: -

          - -
          template<classLessThanComparable T>
-requires CopyConstructible<T>
-pair<const T&, const T&>
-minmax(initializer_list<T> t);
-
-template<class T, classStrictWeakOrder<auto, T> Compare>
-requires CopyConstructible<T>
-pair<const T&, const T&>
-minmax(initializer_list<T> t, Compare comp);
-
          -
          2. -
        2. -

          -In 25.5.7 [alg.min.max] change as indicated (Begin: Just before p.20): -

          -
          template<classLessThanComparable T>
-  requires CopyConstructible<T>
-  pair<const T&, const T&>
-  minmax(initializer_list<T> t);
-
          -
          -

          --20- Requires: T is LessThanComparable and -CopyConstructible. -

          -

          --21- Returns: pair<const T&, const -T&>(x, y) where x is the -smallest value and y the largest value in the initializer_list. -

          -
          - -

          [..]

          -
          template<class T, classStrictWeakOrder<auto, T> Compare>
-  requires CopyConstructible<T>
-  pair<const T&, const T&>
-  minmax(initializer_list<T> t, Compare comp);
-
          - -
          -

          --24- Requires: type T is LessThanComparable and CopyConstructible. -

          -

          --25- Returns: pair<const T&, const -T&>(x, y) where x is the -smallest value and y largest value in the initializer_list. -

          -
          -
          -
          3. -
        - - - - - - -
        -

        916. Redundant move-assignment operator of pair should be removed

        -

        Section: 20.3.3 [pairs] Status: Open - Submitter: Daniel Krügler Opened: 2008-10-04 Last modified: 2009-05-23

        -

        View other active issues in [pairs].

        -

        View all other issues in [pairs].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        see also 917.

        - -

        -The current WP provides the following assignment operators for pair -in 20.3.3 [pairs]/1: -

        - -
          -
        1. -
          template<class U , class V>
-requires HasAssign<T1, const U&> && HasAssign<T2, const V&>
-pair& operator=(const pair<U , V>& p);
-
          -
          2. -
        2. -
          requires MoveAssignable<T1> && MoveAssignable<T2> pair& operator=(pair&& p );
-
          -
          3. -
        3. -
          template<class U , class V>
-requires HasAssign<T1, RvalueOf<U>::type> && HasAssign<T2, RvalueOf<V>::type>
-pair& operator=(pair<U , V>&& p);
-
          -
          4. -
        - -

        -It seems that the functionality of (2) is completely covered by (3), therefore -(2) should be removed. -

        - -

        [ -Batavia (2009-05): -]

        - -
        -

        -Bill believes the extra assignment operators are necessary for resolving -ambiguities, but that does not mean it needs to be part of the specification. -

        -

        -Move to Open. -We recommend this be looked at in the context of the ongoing work -related to the pair templates. -

        -
        - - -

        Proposed resolution:

        -
          -
        1. -

          -In 20.3.3 [pairs] p. 1, class pair and just before p. 13 remove the declaration: -

          - -
          requires MoveAssignable<T1> && MoveAssignable<T2> pair& operator=(pair&& p );
-
          -
          2. - -
        2. -Remove p.13+p.14 -
          3. - -
        - - - - - -
        -

        917. Redundant move-assignment operator of tuple should be removed

        -

        Section: 20.5.2.1 [tuple.cnstr] Status: Open - Submitter: Daniel Krügler Opened: 2008-10-04 Last modified: 2009-05-23

        -

        View other active issues in [tuple.cnstr].

        -

        View all other issues in [tuple.cnstr].

        -

        View all issues with Open status.

        -

        Discussion:

        -

        see also 916.

        -

        -N2770 (and thus now the WP) removed the -non-template move-assignment operator from tuple's class definition, -but the latter individual member description does still provide this -operator. Is this (a) an oversight and can it (b) be solved as part of an -editorial process? -

        - -

        [ -Post Summit Daniel provided wording. -]

        - - -

        [ -Batavia (2009-05): -]

        - -
        -

        -We believe that the proposed resolution's part 1 is editorial. -

        -

        -Regarding part 2, we either remove the specification as proposed, -or else add back the declaration to which the specification refers. -Alisdair and Bill prefer the latter. -It is not immediately obvious whether the function is intended to be present. -

        -

        -We recommend that the Project Editor restore the missing declaration -and that we keep part 2 of the issue alive. -

        -

        -Move to Open. -

        -
        - - - -

        Proposed resolution:

        -
          -
        1. -

          -In 20.5.2 [tuple.tuple], class tuple just before member swap please -change as indicated: -

          -

          [ -This fixes an editorial loss between N2798 to N2800 -]

          - -
          template <class... UTypes>
-requires HasAssign<Types, const UTypes&>...
-tuple& operator=(const pair<UTypes...>&);
-
-template <class... UTypes>
-requires HasAssign<Types, RvalueOf<UTypes>::type>...
-tuple& operator=(pair<UTypes...>&&);
-
          -
          2. -
        2. -

          -In 20.5.2.1 [tuple.cnstr], starting just before p. 11 please remove -as indicated: -

          - -
          requires MoveAssignable<Types>... tuple& operator=(tuple&& u);
-
          -
          -

          --11- Effects: Move-assigns each element of u to the corresponding -element of *this. -

          -

          --12- Returns: *this. -

          -
          -
          -
          3. -
        - - - - - -
        -

        918. Swap for tuple needs to be conceptualized

        -

        Section: 20.5.2.6 [tuple.swap] Status: Tentatively NAD - Submitter: Daniel Krügler Opened: 2008-10-04 Last modified: 2009-05-23

        -

        View all issues with Tentatively NAD status.

        -

        Discussion:

        -

        -Issue 522 was accepted after tuple had been conceptualized, -therefore this step needs to be completed. -

        - -

        [ -Post Summit Daniel adds -]

        - - -
        -This is now NAD Editorial (addressed by -N2844) -except for item 3 in the proposed wording. -
        - -

        [ -2009-05-01 Daniel adds: -]

        - - -
        -As of the recent WP -(N2857), -this issue is now completely covered by editorial -changes (including the third bullet), therefore I unconditionally recommend -NAD. -
        - -

        [ -Batavia (2009-05): -]

        - -
        -

        -We observed that all the proposed changes have already been applied to the -Working Draft, rendering this issue moot. -

        -

        -Move to NAD. -

        -
        - - - -

        Proposed resolution:

        -
          -
        1. -

          -In both 20.5.1 [tuple.general]/2 and 20.5.2.7 [tuple.special] change -

          - -
          template <class Swappable... Types>
-void swap(tuple<Types...>& x, tuple<Types...>& y);
-
          - -
          2. - -
        2. -

          -In 20.5.2 [tuple.tuple], class tuple definition and in -20.5.2.6 [tuple.swap], change -

          - -
          requires Swappable<Types>...void swap(tuple&);
-
          - -
          3. - -
        3. -

          -In 20.5.2.6 [tuple.swap] remove the current requires-clause, which says: -

          - -
          -Requires: Each type in Types shall be Swappable -
          -
          4. - -
        - - - - - - -
        -

        919. (forward_)list specialized remove algorithms are over constrained

        -

        Section: 23.3.3.5 [forwardlist.ops], 23.3.4.4 [list.ops] Status: Review - Submitter: Daniel Krügler Opened: 2008-10-06 Last modified: 2009-05-23

        -

        View other active issues in [forwardlist.ops].

        -

        View all other issues in [forwardlist.ops].

        -

        View all issues with Review status.

        -

        Discussion:

        -

        -The signatures of forwardlist::remove and list::remove -defined in 23.3.3.5 [forwardlist.ops] before 11 + 23.3.4.4 [list.ops] before 15: -

        - -
        requires EqualityComparable<T> void remove(const T& value);
-
        - -

        -are asymmetric to their predicate variants (which only require -Predicate, not EquivalenceRelation) and with the free algorithm -remove (which only require HasEqualTo). Also, nothing in the -pre-concept WP -N2723 -implies that EqualityComparable should -be the intended requirement. -

        - -

        [ -Batavia (2009-05): -]

        - -
        -

        -We agree with the proposed resolution, -but would like additional input from concepts experts. -

        -

        -Move to Review. -

        -
        - - -

        Proposed resolution:

        -
          -
        1. -

          -Replace in 23.3.3.5 [forwardlist.ops] before 11 and in 23.3.4.4 [list.ops] before 15 -

          - -
          requires EqualityComparable<T> HasEqualTo<T, T> void remove(const T& value);
-
          -
          2. -
        - - - - - - -
        -

        920. Ref-qualification support in the library

        -

        Section: 20.7.15 [func.memfn] Status: Open - Submitter: Bronek Kozicki Opened: 2008-10-06 Last modified: 2009-05-23

        -

        View all issues with Open status.

        -

        Discussion:

        -

        -Daniel Krügler wrote: -

        - -
        -

        -Shouldn't above list be completed for &- and &&-qualified -member functions This would cause to add: -

        -
        template<Returnable R, class T, CopyConstructible... Args>
-unspecified mem_fn(R (T::* pm)(Args...) &);
-template<Returnable R, class T, CopyConstructible... Args>
-unspecified mem_fn(R (T::* pm)(Args...) const &);
-template<Returnable R, class T, CopyConstructible... Args>
-unspecified mem_fn(R (T::* pm)(Args...) volatile &);
-template<Returnable R, class T, CopyConstructible... Args>
-unspecified mem_fn(R (T::* pm)(Args...) const volatile &);
-template<Returnable R, class T, CopyConstructible... Args>
-unspecified mem_fn(R (T::* pm)(Args...) &&);
-template<Returnable R, class T, CopyConstructible... Args>
-unspecified mem_fn(R (T::* pm)(Args...) const &&);
-template<Returnable R, class T, CopyConstructible... Args>
-unspecified mem_fn(R (T::* pm)(Args...) volatile &&);
-template<Returnable R, class T, CopyConstructible... Args>
-unspecified mem_fn(R (T::* pm)(Args...) const volatile &&);
-
        - -
        - -

        -yes, absolutely. Thanks for spotting this. Without this change mem_fn -cannot be initialized from pointer to ref-qualified member function. I -believe semantics of such function pointer is well defined. -

        - -

        [ -Post Summit Daniel provided wording. -]

        - - -

        [ -Batavia (2009-05): -]

        - -
        -

        -We need to think about whether we really want to go down the proposed path -of combinatorial explosion. -Perhaps a Note would suffice. -

        -

        -We would really like to have an implementation before proceeding. -

        -

        -Move to Open, and recommend this be deferred until after the next -Committee Draft has been issued. -

        -
        - - -

        Proposed resolution:

        -
          -
        1. -

          -In 20.7 [function.objects]/2, header <functional> synopsis, just after -the section "// 20.6.15, member function adaptors::" add the following -declarations to the existing list: -

          -
          template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) volatile &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const volatile &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) &&);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const &&);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) volatile &&);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const volatile &&);
-
          -
          2. -
        2. -

          -In 20.7.15 [func.memfn] add the following declarations to the existing -list: -

          -
          template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) volatile &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const volatile &);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) &&);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const &&);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) volatile &&);
-template<Returnable R, class T, CopyConstructible... Args>
-  unspecified mem_fn(R (T::* pm)(Args...) const volatile &&);
-
          -
          3. -
        -

        -The following text, most notably p.2 and p.3 which discuss influence -of the cv-qualification on the definition of the base class's first template -parameter remains unchanged. -

        - - - - +duration specified by rel_time has elapsed. + + + -
        -

        921. Rational Arithmetic should use template aliases

        -

        Section: 20.4.1 [ratio.ratio] Status: Review - Submitter: Pablo Halpern Opened: 2008-10-07 Last modified: 2009-05-23

        -

        View other active issues in [ratio.ratio].

        -

        View all other issues in [ratio.ratio].

        -

        View all issues with Review status.

        -

        Discussion:

        -The compile-time functions that operate on ratio<N,D> require the -cumbersome and error-prone "evaluation" of a type member using a -meta-programming style that predates the invention of template aliases. -Thus, multiplying three ratios a, b, and c requires the expression: +24 [Note: There is no blocking if pred() is initially true, +even if the timeout has already expired. -- end note]

        -
        ratio_multiply<a, ratio_multiply<b, c>::type>::type
-
        +

        +Postcondition: lock is locked by the calling thread. +

        -The simpler expression: +25 Returns: pred()

        -
        ratio_multiply<a, ratio_multiply<b, c>>
-
        -

        -Could be used by if template aliases were employed in the definitions. +26 [Note: The returned value indicates whether the predicate evaluates to +true regardless of whether the timeout was triggered. -- end note]

        -

        [ -Post Summit: -]

        - - -
        -

        -Jens: not a complete proposed resolution: "would need to make similar change" -

        -

        -Consensus: We agree with the direction of the issue. -

        -

        -Recommend Open. -

        -
        +

        +Throws: std::system_error when the effects or postcondition cannot be achieved. +

        -

        [ -2009-05-11 Daniel adds: -]

        +

        +Error conditions: +

        +
          +
        • +operation_not_permitted -- if the thread does not own the lock. +
          • +
        • +equivalent error condition from lock.lock() or lock.unlock(). +
          • +
        -
        -

        -Personally I'm not in favor for the addition of: -

        -
        typedef ratio type;
-
        -

        -For a reader of the -standard it's usage or purpose is unclear. I haven't seen similar examples -of attempts to satisfy non-feature complete compilers. -

        - -

        [ -2009-05-11 Pablo adds: -]

        + -
        -

        -The addition of type to the ratio template allows the previous style -(i.e., in the prototype implementations) to remain valid and permits the -use of transitional library implementations for C++03 compilers. I do -not feel strongly about its inclusion, however, and leave it up to the -reviewers to decide. -

        -
        -

        [ -Batavia (2009-05): -]

        -
        -Bill asks for additional discussion in the issue -that spells out more details of the implementation. -Howard points us to issue 948 -which has at least most of the requested details. -Tom is strongly in favor of overflow-checking at compile time. -Pete points out that there is no change of functionality implied. -We agree with the proposed resolution, -but recommend moving the issue to Review -to allow time to improve the discussion if needed. -
        -

        Proposed resolution:

        - -
          -
        1. +
          +

          860. Floating-Point State

          +

          Section: 26 [numerics] Status: Open + Submitter: Lawrence Crowl Opened: 2008-06-23 Last modified: 2009-03-09

          +

          View all other issues in [numerics].

          +

          View all issues with Open status.

          +

          Discussion:

          -In 20.4 [ratio]/3 change as indicated: +There are a number of functions that affect the floating point state. +These function need to be thread-safe, but I'm unsure of the right +approach in the standard, as we inherit them from C.

          -
          // ratio arithmetic
-template <class R1, class R2> structusing ratio_add = see below;
-template <class R1, class R2> structusing ratio_subtract = see below;
-template <class R1, class R2> structusing ratio_multiply = see below;
-template <class R1, class R2> structusing ratio_divide = see below;
-
          -
          2. -
        2. -

          -In 20.4.1 [ratio.ratio], change as indicated: -

          -
          namespace std {
-  template <intmax_t N, intmax_t D = 1>
-  class ratio {
-  public:
-    typedef ratio type;
-    static const intmax_t num;
-    static const intmax_t den;
-  };
-}
-
          -
          3. -
        3. -

          -In 20.4.2 [ratio.arithmetic] change as indicated: -

          +

          [ +San Francisco: +]

          -
          template <class R1, class R2> structusing ratio_add = see below{
-  typedef see below type;
-};
-

          -1 The nested typedef type ratio_add<R1, R2> -shall be a synonym for ratio<T1, T2> -where T1 has the value R1::num * R2::den + R2::num * R1::den and T2 -has the value R1::den * R2::den. +Nick: I think we already say that these functions do not introduce data +races; see 17.6.5.6/20

          -
          -
          -
          template <class R1, class R2> structusing ratio_subtract = see below{
-  typedef see below type;
-};
-
          -

          -2 The nested typedef type ratio_subtract<R1, R2> -shall be a synonym for ratio<T1, T2> -where T1 has the value R1::num * R2::den - R2::num * R1::den and T2 -has the value R1::den * R2::den. +Pete: there's more to it than not introducing data races; are these +states maintained per thread?

          -
          -
          -
          template <class R1, class R2> structusing ratio_multiply = see below{
-  typedef see below type;
-};
-
          -

          -3 The nested typedef type ratio_multiply<R1, R2> -shall be a synonym for ratio<T1, T2> -where T1 has the value R1::num * R2::num and T2 has the value R1::den * R2::den. +Howard: 21.5/14 says that strtok and strerror are not required to avoid +data races, and 20.9/2 says the same about asctime, gmtime, ctime, and +gmtime.

          -
          -
          -
          template <class R1, class R2> structusing ratio_divide = see below{
-  typedef see below type;
-};
-
          -

          -4 The nested typedef type ratio_divide<R1, R2> -shall be a synonym for ratio<T1, T2> -where T1 has the value R1::num * R2::den and T2 has the value R1::den * R2::num. +Nick: POSIX has a list of not-safe functions. All other functions are +implicitly thread safe.

          -
          -
          -
          4. -

        4. -In 20.9.3.1 [time.duration.cons]/4 change as indicated: +Lawrence is to form a group between meetings to attack this issue. Nick +and Tom volunteered to work with Lawrence.

          -

          -Requires: treat_as_floating_point<rep>::value shall be true or -ratio_divide<Period2, period>::type::den shall be 1.[..] +Move to Open.

          -
          5. -
        5. + +

          [ +Post Summit: +]

          + + +

          -In 20.9.3.7 [time.duration.cast]/2 change as indicated: +Hans: Sane oses seem ok. Sensible thing is implementable and makes sense.

          -

          -Returns: Let CF be ratio_divide<Period, typename -ToDuration::period>::type, and [..] +Nick: Default wording seems to cover this? Hole in POSIX, these +functions need to be added to list of thread-unsafe functions.

          -
          -
          6. -
        - - - - - -
        -

        922. [func.bind.place] Number of placeholders

        -

        Section: B [implimits] Status: Tentatively Ready - Submitter: Sohail Somani Opened: 2008-10-11 Last modified: 2009-03-13

        -

        View all issues with Tentatively Ready status.

        -

        Discussion:

        -

        Addresses DE 24

        -

        -With respect to the section 20.7.12.1.4 [func.bind.place]: +Lawrence: Not sufficient, not "thread-safe" per our definition, but +think of state as a thread-local variable. Need something like "these +functions only affect state in the current thread."

        -TR1 dropped some suggested implementation quantities for the number of -placeholders. The purpose of this defect is to put these back for C++0x. +Hans: Suggest the following wording: "The floating point environment is +maintained per-thread."

        - -

        [ -Post Summit: -]

        - - -

        -see DE 24 +Walter: Any other examples of state being thread safe that are not +already covered elsewhere?

        -Recommend applying the proposed resolution from DE 24, with that -Tentatively Ready. +Have thread unsafe functions paper which needs to be updated. Should +just fold in 26.3 [cfenv] functions.

        -
        - -Original proposed resolution: -

        -Add 20.7.12.1.4 [func.bind.place]/2: +Recommend Open. Lawrence instead suggests leaving it open until we have +suitable wording that may or may not include the thread local +commentary.

        - -
        -While the exact number of placeholders (_M) is implementation defined, -this number shall be at least 10.
        -

        Proposed resolution:

        -

        -Add to B [implimits]:

        -
          -
        • -Number of placeholders (20.7.12.1.4 [func.bind.place]) [10]. -
          • -
        - -
        -

        923. atomics with floating-point

        -

        Section: 29 [atomics] Status: Open - Submitter: Herb Sutter Opened: 2008-10-17 Last modified: 2009-05-01

        -

        View other active issues in [atomics].

        -

        View all other issues in [atomics].

        +

        861. Incomplete specification of EqualityComparable for std::forward_list

        +

        Section: 23.2 [container.requirements] Status: Open + Submitter: Daniel Krügler Opened: 2008-06-24 Last modified: 2009-07-26

        +

        View other active issues in [container.requirements].

        +

        View all other issues in [container.requirements].

        View all issues with Open status.

        Discussion:

        -Right now, C++0x doesn't have atomic<float>. We're thinking of adding -the words to support it for TR2 (note: that would be slightly -post-C++0x). If we need it, we could probably add the words. +Table 89, Container requirements, defines operator== in terms of the container +member function size() and the algorithm std::equal:

        + +
        +== is an equivalence relation. a.size() == b.size() && +equal(a.begin(), a.end(), b.begin() +
        +

        -Proposed resolutions: Using atomic<FP>::compare_exchange (weak or -strong) should be either: +The new container forward_list does not provide a size member function +by design but does provide operator== and operator!= without specifying it's semantic. +

        +

        +Other parts of the (sequence) container requirements do also depend on +size(), e.g. empty() +or clear(), but this issue explicitly attempts to solve the missing +EqualityComparable specification, +because of the special design choices of forward_list. +

        +

        +I propose to apply one of the following resolutions, which are described as:

        -
          +
          1. -ill-formed, or +Provide a definition, which is optimal for this special container without +previous size test. This choice prevents two O(N) calls of std::distance() +with the corresponding container ranges and instead uses a special +equals implementation which takes two container ranges instead of 1 1/2.
          2. -well-defined. +The simple fix where the usual test is adapted such that size() is replaced +by distance with corresponding performance disadvantages.
          -

          -I propose Option 1 for C++0x for expediency. If someone wants to argue -for Option 2, they need to say what exactly they want compare_exchange -to mean in this case (IIRC, C++0x doesn't even assume IEEE 754). +Both proposal choices are discussed, the preferred choice of the author is +to apply (A).

          [ -Summit: +San Francisco: ]

          -Move to open. Blocked until concepts for atomics are addressed. +

          +There's an Option C: change the requirements table to use distance(). +

          +

          +LWG found Option C acceptable. +

          +

          +Martin will draft the wording for Option C. +

          [ -Post Summit Anthony adds: +post San Francisco: ]

          -

          -Recommend NAD. C++0x does have std::atomic<float>, and both -compare_exchange_weak and compare_exchange_strong are well-defined in -this case. Maybe change the note in 29.6 [atomics.types.operations] paragraph 20 to: -

          +Martin provided wording for Option C. +
          + +

          [ +2009-07 Frankfurt +]

          +

          -[Note: The effect of the compare-and-exchange operations is +Other operational semantics (see, for example, Tables 82 and 83) are +written in terms of a container's size() member. Daniel to update +proposed resolution C.

          -
          if (!memcmp(object,expected,sizeof(*object)))
-    *object = desired;
-else
-    *expected = *object;
-
          +

          [ +Howard: Commented out options A and B. +]

          -

          -This may result in failed comparisons for values that compare equal if -the underlying type has padding bits or alternate representations of -the same value. -- end note] -

          - +

          [ +2009-07-26 Daniel updated proposed resolution C. +]

          +

          Proposed resolution:

          + +

          -Change the note in 29.6 [atomics.types.operations] paragraph 20 to: +Option (C):

          -
          + +

          [ +The changes are relative to +N2914 +but concept-free. +]

          + + +
            +

          1. -[Note: The effect of the compare-and-exchange operations is +In 23.2.1 [container.requirements.general] change Table 80 -- Container requirements as indicated:

            -
            if (*object == *expected !memcmp(object,expected,sizeof(*object)))
-    *object = desired;
-else
-    *expected = *object;
-
            -

            -This may result in failed comparisons for values that compare equal if -the underlying type has padding bits or alternate representations of -the same value. -- end note] +

              +
            1. +

              +Change the text in the Assertion/note column in the row for "X u;" +as follows:

              + +
              +post: u.size() == 0empty() == true
              +
              2. +
            2. +

              +Change the text in the Assertion/note column in the row for "X();" +as follows: +

              +
              +X().size() == 0empty() == true +
              +
              3. +
            3. +

              +Change the text in the Operational Semantics column in the row for +"a == b" as follows: +

              +
              +== is an equivalence relation. +a.size()distance(a.begin(), a.end()) == + b.size()distance(b.begin(), b.end()) && +equal(a.begin(), a.end(), b.begin()) +
              +
              4. +
            4. +

              +Change the text in the Operational Semantics column in the row for +"a.size()" as follows: +

              +
              +a.end() - a.begin()distance(a.begin(), a.end()) +
              +
              5. -
              -

              924. structs with internal padding

              -

              Section: 29 [atomics] Status: Open - Submitter: Herb Sutter Opened: 2008-10-17 Last modified: 2009-03-22

              -

              View other active issues in [atomics].

              -

              View all other issues in [atomics].

              -

              View all issues with Open status.

              -

              Discussion:

              +

            5. -Right now, the compare_exchange_weak loop should rapidly converge on the -padding contents. But compare_exchange_strong will require a bit more -compiler work to ignore padding for comparison purposes. +Change the text in the Operational Semantics column in the row for +"a.max_size()" as follows:

              + +
              +size()distance(begin(), end()) of the largest +possible container +
              +
              6. + +

            6. -Note that this isn't a problem for structs with no padding, and we do -already have one portable way to ensure that there is no padding that -covers the key use cases: Have elements be the same type. I suspect that -the greatest need is for a structure of two pointers, which has no -padding problem. I suspect the second need is a structure of a pointer -and some form of an integer. If that integer is intptr_t, there will be -no padding. +Change the text in the Operational Semantics column in the row for +"a.empty()" as follows:

              + +
              +a.size() == 0a.begin() == a.end() +
              +
              7. +
            +
            2. + +

          2. -Related but separable issue: For unused bitfields, or other unused -fields for that matter, we should probably say it's the programmer's -responsibility to set them to zero or otherwise ensure they'll be -ignored by memcmp. +In 23.2.1 [container.requirements.general] change Table 82 -- Allocator-aware container requirements as indicated:

            +
              +

            1. -Proposed resolutions: Using -atomic<struct-with-padding>::compare_exchange_strong should be either: +Change the text in the Assertion/note column in the row for "X() / +X u;" as follows:

              -
                -
              1. -ill-formed, or +
                +Requires: A is DefaultConstructible post: u.size() == +0u.empty() == true, get_allocator() == A() +
                2. +
              2. -well-defined. +

                +Change the text in the Assertion/note column in the row for "X(m) / +X u(m);" as follows: +

                + +
                +post: u.size() == 0u.empty() == true, +get_allocator() == m +
              +
              2. +

            2. -I propose Option 1 for C++0x for expediency, though I'm not sure how to -say it. I would be happy with Option 2, which I believe would mean that -compare_exchange_strong would be implemented to avoid comparing padding -bytes, or something equivalent such as always zeroing out padding when -loading/storing/comparing. (Either implementation might require compiler -support.) +In 23.2.3 [sequence.reqmts] change Table 83 -- Sequence container requirements as indicated:

              -

              [ -Summit: -]

              - +
                +
              1. +

                +Change the text in the Assertion/note column in the row for "X(n, +t) / X a(n, t)" as follows: +

                -Move to open. Blocked until concepts for atomics are addressed. +post: size()distance(begin(), end()) == n [..]
                +
                2. -

                [ -Post Summit Anthony adds: -]

                - +
              2. +

                +Change the text in the Assertion/note column in the row for "X(i, +j) / X a(i, j)" as follows: +

                -The resoultion of LWG 923 should resolve this issue as well. +[..] post: size() == distance between i and +jdistance(begin(), end()) == distance(i, j) [..]
                +
                3. - - -

                Proposed resolution:

                +

              3. +Change the text in the Assertion/note column in the row for +"a.clear()" as follows:

                +
                +a.erase(a.begin(), a.end()) post: +size() == 0a.empty() == true +
                +
                4. +
              +
              3. +
            3. +

              +In 23.2.4 [associative.reqmts] change Table 85 -- Associative container requirements as indicated: +

              +

              [ +Not every occurrence of size() was replaced, because all current +associative containers +have a size. The following changes ensure consistency regarding the +semantics of "erase" +for all tables and adds some missing objects +]

              - -
              -

              925. shared_ptr's explicit conversion from unique_ptr

              -

              Section: 20.8.13.2.1 [util.smartptr.shared.const] Status: Tentatively Ready - Submitter: Rodolfo Lima Opened: 2008-10-12 Last modified: 2009-05-23

              -

              View other active issues in [util.smartptr.shared.const].

              -

              View all other issues in [util.smartptr.shared.const].

              -

              View all issues with Tentatively Ready status.

              -

              Discussion:

              +
                +
              1. +

                +Change the text in the Complexity column in the row for +"a.insert(i, j)" as follows: +

                +
                +N log(a.size() + N) (N is the distance from i to +j) where N == distance(i, j) +
                +
                2. + +

              2. -The current working draft -(N2798), -section 20.8.13.2.1 [util.smartptr.shared.const] declares -shared_ptr's constructor that takes a rvalue reference to unique_ptr and -auto_ptr as being explicit, affecting several valid smart pointer use -cases that would take advantage of this conversion being implicit, for -example: +Change the text in the Complexity column in the row for +"a.erase(k)" as follows:

                +
                +log(a.size()) + a.count(k) +
                +
                3. -
                class A;
-std::unique_ptr<A> create();
-void process(std::shared_ptr<A> obj);
-
-int main()
-{
-   process(create());                  // use case #1
-   std::unique_ptr<A> uobj = create();
-   process(std::move(uobj));           // use case #2
-   return 0;
-}
-
                - +

              3. -If unique_ptr to shared_ptr conversions are explicit, the above lines -should be written: +Change the text in the Complexity column in the row for +"a.erase(q1, q2)" as follows:

                -
                process(std::shared_ptr<A>(create()));        // use case #1
-process(std::shared_ptr<A>(std::move(uobj))); // use case #2
-
                +
                +log(a.size()) + N where N is the distance from q1 +to q2 + == distance(q1, q2). +
                +
                4. +

              4. -The extra cast required doesn't seems to give any benefits to the user, -nor protects him of any unintended conversions, this being the raison -d'etre of explicit constructors. +Change the text in the Assertion/note column in the row for +"a.clear()" as follows:

                +
                +a.erase(a.begin(),a.end()) post: size() == +0a.empty() == true +
                +
                5. + +

              5. -It seems that this constructor was made explicit to mimic the conversion -from auto_ptr in pre-rvalue reference days, which accepts both lvalue and -rvalue references. Although this decision was valid back then, C++0x -allows the user to express in a clear and non verbose manner when he wants -move semantics to be employed, be it implicitly (use case 1) or explicitly -(use case 2). +Change the text in the Complexity column in the row for "a.clear()" +as follows:

                -

                [ -Batavia (2009-05): -]

                -
                +linear in a.size() +
                +
                6. + +

              6. -Howard and Alisdair like the motivating use cases -and the proposed resolution. +Change the text in the Complexity column in the row for +"a.count(k)" as follows:

                + +
                +log(a.size()) + a.count(k) +
                +
                7. +
              +
              4. + +

            4. -Move to Tentatively Ready. +In 23.2.5 [unord.req] change Table 87 -- Unordered associative container requirements as indicated:

              -
          +

          [ +The same rational as for Table 85 applies here +]

          -

          Proposed resolution:

          +
            +

          1. -In both 20.8.13.2 [util.smartptr.shared] paragraph 1 and -20.8.13.2.1 [util.smartptr.shared.const] change: +Change the text in the Assertion/note column in the row for +"a.clear()" as follows:

            -
            template <class Y> explicit shared_ptr(auto_ptr<Y> &&r);
-template <class Y, class D> explicit shared_ptr(unique_ptr<Y, D> &&r);
-
            +
            +[..] Post: a.size() == 0empty() == true +
            +
            2. +
          + +
        + +
        -

        926. Sequentially consistent fences, relaxed operations and modification order

        -

        Section: 29.3 [atomics.order] Status: Open - Submitter: Anthony Williams Opened: 2008-10-19 Last modified: 2009-03-22

        -

        View all other issues in [atomics.order].

        +

        865. More algorithms that throw away information

        +

        Section: 25.4.6 [alg.fill], 25.4.7 [alg.generate] Status: Open + Submitter: Daniel Krügler Opened: 2008-07-13 Last modified: 2009-07-25

        View all issues with Open status.

        Discussion:

        -

        Addresses UK 313

        -

        -There was an interesting issue raised over on comp.programming.threads -today regarding the following example +In regard to library defect 488 I found some more algorithms which +unnecessarily throw away information. These are typically algorithms, +which sequentially write into an OutputIterator, but do not return the +final value of this output iterator. These cases are:

        -
        // Thread 1:
-x.store(1, memory_order_relaxed);           // SX
-atomic_thread_fence(memory_order_seq_cst);  // F1
-y.store(1, memory_order_relaxed);           // SY1
-atomic_thread_fence(memory_order_seq_cst);  // F2
-r1 = y.load(memory_order_relaxed);          // RY
-
-// Thread 2:
-y.store(0, memory_order_relaxed);          // SY2
-atomic_thread_fence(memory_order_seq_cst); // F3
-r2 = x.load(memory_order_relaxed);         // RX
-
        +
          +
        1. +
          template<class OutputIterator, class Size, class T>
+void fill_n(OutputIterator first, Size n, const T& value);
          2. +
        2. +
          template<class OutputIterator, class Size, class Generator>
+void generate_n(OutputIterator first, Size n, Generator gen);
          3. +

        -is the outcome r1 == 0 and r2 == 0 possible? -

        -

        -I think the intent is that this is not possible, but I am not sure the -wording guarantees that. Here is my analysis: -

        -

        -Since all the fences are SC, there must be a total order between them. -F1 must be before F2 in that order since they are in -the same thread. Therefore F3 is either before F1, -between F1 and F2 or after F2. -

        -

        -If F3 is after F2, then we can apply 29.3 [atomics.order]p5 from -N2798: +In both cases the minimum requirements on the iterator are +OutputIterator, which means according to the requirements of +24.2.3 [output.iterators]/2 that only single-pass iterations are guaranteed. +So, if users of fill_n and generate_n have *only* an OutputIterator +available, they have no chance to continue pushing further values +into it, which seems to be a severe limitation to me.

        -
        -For atomic operations A and B on an atomic object -M, where A modifies M and B takes -its value, if there are memory_order_seq_cst fences X -and Y such that A is sequenced before X, -Y is sequenced before B, and X precedes -Y in S, then B observes either the effects of -A or a later modification of M in its modification -order. -
        +

        [ +Post Summit Daniel "conceptualized" the wording. +]

        + +

        [ +Batavia (2009-05): +]

        + +

        -In this case, A is SX, B is RX, the -fence X is F2 and the fence Y is F3, -so RX must see 1. -

        -

        -If F3 is before F2, this doesn't apply, but -F3 can therefore be before or after F1. -

        -

        -If F3 is after F1, the same logic applies, but this -time the fence X is F1. Therefore again, RX -must see 1. -

        -

        -Finally we have the case that F3 is before F1 -in the SC ordering. There are now no guarantees about RX, and -RX can see r2==0. -

        -

        -We can apply 29.3 [atomics.order]p5 again. This time, -A is SY2, B is RY, X is -F3 and Y is F1. Thus RY must observe -the effects of SY2 or a later modification of y in its -modification order. +Alisdair likes the idea, but has concerns about the specific wording +about the returns clauses.

        -Since SY1 is sequenced before RY, RY must -observe the effects of SY1 or a later modification of -y in its modification order. +Alan notes this is a feature request.

        -In order to ensure that RY sees (r1==1), we must see -that SY1 is later in the modification order of y than -SY2. +Bill notes we have made similar changes to other algorithms.

        -We're now skating on thin ice. Conceptually, SY2 happens-before -F3, F3 is SC-ordered before F1, F1 -happens-before SY1, so SY1 is later in the -modification order M of y, and RY must see -the result of SY1 (r1==1). However, I don't think the -words are clear on that. +Move to Open.

        +

        [ -Post Summit Hans adds: +2009-07 Frankfurt ]

        -

        -In my (Hans') view, our definition of fences will always be weaker than -what particular hardware will guarantee. Memory_order_seq_cst fences -inherently don't guarantee sequential consistency anyway, for good -reasons (e.g. because they can't enforce a total order on stores). - Hence I don't think the issue demonstrates a gross failure to achieve -what we intended to achieve. The example in question is a bit esoteric. - Hence, in my view, living with the status quo certainly wouldn't be a -disaster either. -

        -

        -In any case, we should probably add text along the lines of the -following between p5 and p6 in 29.3 [atomics.order]: -

        -
        -[Note: Memory_order_seq_cst only ensures sequential consistency for a -data-race-free program that uses exclusively memory_order_seq_cst -operations. Any use of weaker ordering will invalidate this guarantee -unless extreme care is used. In particular, memory_order_seq_cst fences -only ensure a total order for the fences themselves. They cannot, in -general, be used to restore sequential consistency for atomic operations -with weaker ordering specifications.] +We have a consensus for moving forward on this issue, but Daniel needs +to deconceptify it.
        +

        [ +2009-07-25 Daniel provided non-concepts wording. +]

        + + + + +

        Proposed resolution:

        + +
          +

        1. -Also see thread beginning at c++std-lib-23271. +Replace the current declaration of fill_n in 25 [algorithms]/2, header +<algorithm> synopsis and in 25.4.6 [alg.fill] by

          -
        - -

        [ -Herve's correction: -]

        +
        template<class OutputIterator, class Size, class T>
+  voidOutputIterator fill_n(OutputIterator first, Size n, const T& value);
+
        -

        -Minor point, and sorry for the knee jerk reaction: I admit to having -no knowledge of Memory_order_seq_cst, but my former boss (John Lakos) -has ingrained an automatic introspection on the use of "only". I -think you meant: +Just after the effects clause add a new returns clause saying:

        -[Note: Memory_order_seq_cst ensures sequential consistency only -for . . . . In particular, memory_order_seq_cst fences ensure a -total order only for . . . +Returns: For fill_n and positive n, returns first + n. Otherwise +returns first for fill_n.
        + + +

      6. -Unless, of course, Memory_order_seq_cst really do nothing but ensure -sequential consistency for a data-race-free program that uses -exclusively memory_order_seq_cst operations. +Replace the current declaration of generate_n in 25 [algorithms]/2, +header <algorithm> synopsis and in 25.4.7 [alg.generate] by

        -
        7. - +
        template<class OutputIterator, class Size, class Generator>
+  voidOutputIterator generate_n(OutputIterator first, Size n, Generator gen);
+
        -

        Proposed resolution:

        -Add a new paragraph after 29.3 [atomics.order]p5 that says +Just after the effects clause add a new returns clause saying:

        -For atomic operations A and B on an atomic object -M, where A and B modify M, if there -are memory_order_seq_cst fences X and Y such -that A is sequenced before X, Y is sequenced -before B, and X precedes Y in S, -then B occurs later than A in the modifiction order of -M. +For generate_n and positive n, returns first + n. Otherwise +returns first for generate_n.
        + +
      + +
      -

      927. Dereferenceable should be HasDereference

      -

      Section: 20.8.2.2 [allocator.concepts] Status: Tentatively NAD Editorial - Submitter: Pablo Halpern Opened: 2008-10-23 Last modified: 2009-05-23

      -

      View all issues with Tentatively NAD Editorial status.

      +

      868. default construction and value-initialization

      +

      Section: 23 [containers] Status: Review + Submitter: Alberto Ganesh Barbati Opened: 2008-07-22 Last modified: 2009-07-19

      +

      View other active issues in [containers].

      +

      View all other issues in [containers].

      +

      View all issues with Review status.

      Discussion:

      -20.8.2.2 [allocator.concepts] contains a reference to a concept named -Dereferenceable. No such concept exists. +The term "default constructed" is often used in wording that predates +the introduction of the concept of value-initialization. In a few such +places the concept of value-initialization is more correct than the +current wording (for example when the type involved can be a built-in) +so a replacement is in order. Two of such places are already covered by +issue 867. This issue deliberately addresses the hopefully +non-controversial changes in the attempt of being approved more quickly. +A few other occurrences (for example in std::tuple, +std::reverse_iterator and std::move_iterator) are left to separate +issues. For std::reverse_iterator, see also issue 408. This issue is +related with issue 724.

      [ -Daniel adds 2009-02-14: +San Francisco: ]

      -The proposal given in the paper -N2829 -would automatically resolve this issue. +

      +The list provided in the proposed resolution is not complete. James +Dennett will review the library and provide a complete list and will +double-check the vocabulary. +

      +

      +This issue relates to Issue 886 tuple construction +

      -

      [ -Batavia (2009-05): +2009-07 Frankfurt ]

      +

      -This particular set of changes has already been made. -There are two related changes later on (and possibly also an earlier Example); -these can be handled editorially. +The proposed resolution is incomplete.

      -Move to NAD Editorial. +Move to Tentatively NAD Future. Howard will contact Ganesh for wording. +If wording is forthcoming, Howard will move it back to Review.

      +

      [ +2009-07-18 Ganesh updated the proposed wording. +]

      + -

      Proposed resolution:

      +

      -Change all uses of the concept Dereferenceable to -HasDereference in 20.8.2.2 [allocator.concepts]. +Howard: Moved back to Review. Note that X [utility.arg.requirements] +refers to a section that is not in the current working paper, but does refer to +a section that we expect to reappear after the de-concepts merge. This was a +point of confusion we did not recognize when we reviewed this issue in Frankfurt. +

      +

      +Howard: Ganesh also includes a survey of places in the WP surveyed for changes +of this nature and purposefully not treated:

      +
      +

      +Places where changes are not being +proposed +

      +

      +In the following paragraphs, we are not proposing changes because +it's not clear whether we actually prefer value-initialization over +default-initialization (now partially covered by 1012): +

      +
        +

      • 20.8.9.2.1 [unique.ptr.single.ctor] para 3 e 7

        • +

      • 24.5.1.2.1 [reverse.iter.cons] para 1

        • +

      • 24.5.2.2.1 [move.iter.op.const] para 1

        • +
      +

      In the following paragraphs, the expression "default +constructed" need not be changed, because the relevant type does +not depend on a template parameter and has a user-provided +constructor:

      +
        +

      • [func.referenceclosure.invoke] para 12, type: + reference_closure

        • +

      • 30.3.1.2 [thread.thread.constr] para 30, type: thread

        • +

      • 30.3.1.5 [thread.thread.member] para 52, type: thread_id

        • +

      • 30.3.2 [thread.thread.this], para 1, type: thread_id

        • +
      +
      +
      -
      -

      928. Wrong concepts used for tuple's comparison operators

      -

      Section: 20.5.2.5 [tuple.rel] Status: Tentatively Ready - Submitter: Joe Gottman Opened: 2008-10-28 Last modified: 2009-03-09

      -

      View all other issues in [tuple.rel].

      -

      View all issues with Tentatively Ready status.

      -

      Discussion:

      +

      Proposed resolution:

      -In the latest working draft for C++0x, tuple's operator== and operator< -are declared as +Change X [utility.arg.requirements] para 2:

      -
      template<class... TTypes, class... UTypes> 
-  requires EqualityComparable<TTypes, UTypes>... 
-  bool operator==(const tuple<TTypes...>& t, const tuple<UTypes...>& u);
-
      +
      +In general, a default constructor is +not required. Certain container class member function signatures +specify the default constructorT() +as a default argument. T() shall be a well-defined expression (8.5) +if one of those signatures is called using the default argument +(8.3.6). +

      -and +Change 23.3.2.1 [deque.cons] para 5:

      -
      template<class... TTypes, class... UTypes> 
-  requires LessThanComparable<TTypes, UTypes>... 
-  bool operator<(const tuple<TTypes...>& t, const tuple<UTypes...>& u);
-
      +
      +Effects: Constructs a deque with n +default constructedvalue-initialized +elements. +

      -But the concepts EqualityComparable and LessThanComparable only take one -parameter, not two. Also, even if LessThanComparable could take two -parameters, the definition of tuple::operator<() should also require +Change 23.3.2.2 [deque.capacity] para 1:

      -
      LessThanComparable<UTypes, TTypes>... // (note the order) 
-
      +
      +Effects: If sz < size(), equivalent +to erase(begin() + sz, end());. If size() < sz, appends sz - +size() default +constructedvalue-initialized +elements to the sequence. +

      -since the algorithm for tuple::operator< is the following (pseudo-code) +Change 23.3.3.1 [forwardlist.cons] para 5:

      -
      for (size_t N = 0; N < sizeof...(TTypes); ++N) { 
-    if (get<N>(t) < get<N>(u) return true; 
-    else if ((get<N>(u) < get<N>(t)) return false; 
-} 
-
-return false; 
-
      +
      +Effects: Constructs a forward_list object with n default +constructedvalue-initialized +elements. +

      -Similar problems hold for tuples's other comparison operators. +Change 23.3.3.4 [forwardlist.modifiers] para 21:

      -

      [ -Post Summit: -]

      - -
      -Recommend Tentatively Ready. +Effects: [...] For the first signature +the inserted elements are default +constructedvalue-initialized, +and for the second signature they are copies of c.
      +

      +Change 23.3.4.1 [list.cons] para 5: +

      +
      +Effects: Constructs a list with n default +constructedvalue-initialized +elements. +
      -

      Proposed resolution:

      -In 20.5.1 [tuple.general] and 20.5.2.5 [tuple.rel] change: +Change 23.3.4.2 [list.capacity] para 15:

      -
      template<class... TTypes, class... UTypes>
-  requires EqualityComparableHasEqualTo<TTypes, UTypes>...
-  bool operator==(const tuple<TTypes...>&, const tuple<UTypes...>&);
+
      
+Effects: If sz < size(), equivalent
+to list<T>::iterator it = begin(); advance(it, sz); erase(it,
+end());. If size() < sz, appends sz - size() default
+constructedvalue-initialized
+elements to the sequence.
+
      
 
-template<class... TTypes, class... UTypes>
-  requires LessThanComparableHasLess<TTypes, UTypes>... && HasLess<UTypes, TTypes>...
-  bool operator<(const tuple<TTypes...>&, const tuple<UTypes...>&);
+
      
+Change 23.3.6.1 [vector.cons] para 3:
+
      
 
-template<class... TTypes, class... UTypes>
-  requires EqualityComparableHasEqualTo<TTypes, UTypes>...
-  bool operator!=(const tuple<TTypes...>&, const tuple<UTypes...>&);
+
      
+Effects: Constructs a vector with n
+default constructedvalue-initialized
+elements. 
+
      
 
-template<class... TTypes, class... UTypes>
-  requires LessThanComparableHasLess<UTTypes, TUTypes>... && HasLess<UTypes, TTypes>...
-  bool operator>(const tuple<TTypes...>&, const tuple<UTypes...>&);
+
      
+Change 23.3.6.2 [vector.capacity] para 24:
+
      
 
-template<class... TTypes, class... UTypes>
-  requires LessThanComparableHasLess<UTTypes, TUTypes>... && HasLess<UTypes, TTypes>...
-  bool operator<=(const tuple<TTypes...>&, const tuple<UTypes...>&);
+
      
+Effects: If sz < size(), equivalent
+to erase(begin() + sz, end());. If size() < sz, appends sz -
+size() default
+constructedvalue-initialized
+elements to the sequence.
+
      
 
-template<class... TTypes, class... UTypes>
-  requires LessThanComparableHasLess<TTypes, UTypes>... && HasLess<UTypes, TTypes>...
-  bool operator>=(const tuple<TTypes...>&, const tuple<UTypes...>&);
-
      -

      929. Thread constructor

      -

      Section: 30.3.1.2 [thread.thread.constr] Status: Review - Submitter: Anthony Williams Opened: 2008-10-23 Last modified: 2009-05-23

      -

      View other active issues in [thread.thread.constr].

      -

      View all other issues in [thread.thread.constr].

      -

      View all issues with Review status.

      +

      870. Do unordered containers not support function pointers for predicate/hasher?

      +

      Section: 23.2.5 [unord.req] Status: Open + Submitter: Daniel Krügler Opened: 2008-08-17 Last modified: 2009-07-28

      +

      View other active issues in [unord.req].

      +

      View all other issues in [unord.req].

      +

      View all issues with Open status.

      Discussion:

      - -

      Addresses UK 323

      -

      -The thread constructor for starting a new thread with a function and -arguments is overly constrained by the signature requiring rvalue -references for func and args and the CopyConstructible requirements -for the elements of args. The use of an rvalue reference for the -function restricts the potential use of a plain function name, since -the type of the bound parameter will be deduced to be a function -reference and decay to pointer-to-function will not happen. This -therefore complicates the implementation in order to handle a simple -case. Furthermore, the use of rvalue references for args prevents the -array to pointer decay. Since arrays are not CopyConstructible or even -MoveConstructible, this essentially prevents the passing of arrays as -parameters. In particular it prevents the passing of string literals. -Consequently a simple case such as +Good ol' associative containers allow both function pointers and +function objects as feasible +comparators, as described in 23.2.4 [associative.reqmts]/2:

      -
      void f(const char*);
-std::thread t(f,"hello");
-
      +
      +Each associative container is parameterized on Key and an ordering +relation Compare that +induces a strict weak ordering (25.3) on elements of Key. [..]. The +object of type Compare is +called the comparison object of a container. This comparison object +may be a pointer to +function or an object of a type with an appropriate function call operator.[..] +

      -is ill-formed since the type of the string literal is const char[6]. +The corresponding wording for unordered containers is not so clear, +but I read it to disallow +function pointers for the hasher and I miss a clear statement for the +equality predicate, see +23.2.5 [unord.req]/3+4+5:

      +

      -By changing the signature to take all parameters by value we can -eliminate the CopyConstructible requirement and permit the use of -arrays, as the parameter passing semantics will cause the necessary -array-to-pointer decay. They will also cause the function name to -decay to a pointer to function and allow the implementation to handle -functions and function objects identically. +Each unordered associative container is parameterized by Key, by a +function object Hash that +acts as a hash function for values of type Key, and by a binary +predicate Pred that induces an +equivalence relation on values of type Key.[..] +

      +

      +A hash function is a function object that takes a single argument of +type Key and returns a +value of type std::size_t. +

      +

      +Two values k1 and k2 of type Key are considered equal if the +container's equality function object +returns true when passed those values.[..]

      +

      -The new signature of the thread constructor for a function and -arguments is thus: +and table 97 says in the column "assertion...post-condition" for the +expression X::hasher:

      -
      template<typename F,typename... Args>
-thread(F,Args... args);
-
      +
      +Hash shall be a unary function object type such that the expression +hf(k) has type std::size_t. +

      -Since the parameter pack Args can be empty, the single-parameter -constructor that takes just a function by value is now redundant. +Note that 20.7 [function.objects]/1 defines as "Function objects are +objects with an operator() defined.[..]" +

      +

      +Does this restriction exist by design or is it an oversight? If an +oversight, I suggest that to apply +the following

      [ -Howard adds: +2009-07-28 Reopened by Alisdair. No longer solved by concepts. ]

      -
      -

      -I agree with everything Anthony says in this issue. However I believe we -can optimize in such a way as to get the pass-by-value behavior with the -pass-by-rvalue-ref performance. The performance difference is that the latter -removes a move when passing in an lvalue. -

      + +

      Proposed resolution:

      -This circumstance is very analogous to make_pair (20.3.3 [pairs]) -where we started with passing by const reference, changed to pass by value to -get pointer decay, and then changed to pass by rvalue reference, but modified with -decay<T> to retain the pass-by-value behavior. If we were to -apply the same solution here it would look like: +In 23.2.5 [unord.req]/3, just after the second sentence which is written as

      -
      template <class F> explicit thread(F f);
-template <class F, class ...Args> thread(F&& f, Args&&... args);
-
      +Additionally, unordered_map and unordered_multimap associate an +arbitrary mapped type T with the Key. +
      +

      --4- Requires: F and each Ti in Args shall be CopyConstructible -if an lvalue and otherwise MoveConstructible. -INVOKE(f, w1, w2, ..., wN) (20.7.2 [func.require]) shall be a valid expression for -some values w1, w2, ... , wN, where N == sizeof...(Args). -

      -

      --5- Effects: Constructs an object of type thread -and executes INVOKE(f, t1, t2, ..., tN) in a new -thread of execution, where t1, t2, ..., tN are the values in args.... -Constructs -the following objects in memory which is accessible to a new thread of execution -as if: -

      -
      typename decay<F>::type g(std::forward<F>(f));
-tuple<typename decay<Args>::type...> w(std::forward<Args>(args)...);
-
      -

      -The new thread of -execution executes INVOKE(g, wi...) where the wi... refers -to the elements stored in the tuple w. -Any return value from g is ignored. -If f terminates with an uncaught exception, std::terminate() shall be called. -If the evaluation of INVOKE(g, wi...) terminates -with an uncaught exception, std::terminate() shall be called [Note: -std::terminate() could be called before entering g. -- end note]. Any -exception thrown before the evaluation of INVOKE has started shall be -catchable in the calling thread. +add one further sentence:

      -
      + +
      +Both Hash and Pred may be pointers to function or objects of a type +with an appropriate function call operator.

      -Text referring to when terminate() is called was contributed by Ganesh. +[Note1: Since the detailed requirements for Pred and Hash are given in +p.4 and p.5, it an alternative resolution +would be to insert a new paragraph just after p.5, which contains the +above proposed sentence] +

      +

      +[Note2: I do not propose a change of above quoted element in table 97, +because the mis-usage of the +notion of "function object" seems already present in the standard at +several places, even if it includes +function pointers, see e.g. 25 [algorithms]/7. The important point is +that in those places a statement is +given that the actually used symbol, like "Predicate" applies for +function pointers as well]

      -
      +

      Rationale:

      [ -Batavia (2009-05): +San Francisco: ]

      +
      -We agree with the proposed resolution, -but would like the final sentence to be reworded -since "catchable" is not a term of art (and is used nowhere else). +This is fixed by +N2776.
      -

      Proposed resolution:

      -

      -Modify the class definition of std::thread in 30.3.1 [thread.thread.class] to remove the -following signature: -

      -
      template<class F> explicit thread(F f);
-template<class F, class ... Args> explicit thread(F&& f, Args&& ... args);
-
      + + +
      +

      871. Iota's requirements on T are too strong

      +

      Section: 26.7.5 [numeric.iota] Status: Review + Submitter: Daniel Krügler Opened: 2008-08-20 Last modified: 2009-07-30

      +

      View all issues with Review status.

      +

      Discussion:

      -Modify 30.3.1.2 [thread.thread.constr] to replace the constructors prior to paragraph 4 with -the single constructor as above. Replace paragraph 4 - 6 with the -following: +According to the recent WP +N2691, +26.7.5 [numeric.iota]/1, the requires clause +of std::iota says:

      +T shall meet the requirements of CopyConstructible and Assignable types, and +shall be convertible to ForwardIterator's value type.[..] +
      +

      --4- Requires: F and each Ti in Args shall be CopyConstructible -if an lvalue and otherwise MoveConstructible. -INVOKE(f, w1, w2, ..., wN) (20.7.2 [func.require]) shall be a valid expression for -some values w1, w2, ... , wN, where N == sizeof...(Args). -

      -

      --5- Effects: Constructs an object of type thread -and executes INVOKE(f, t1, t2, ..., tN) in a new -thread of execution, where t1, t2, ..., tN are the values in args.... -Constructs -the following objects: +Neither CopyConstructible nor Assignable is needed, instead MoveConstructible +seems to be the correct choice. I guess the current wording resulted as an +artifact from comparing it with similar numerical algorithms like accumulate.

      -
      typename decay<F>::type g(std::forward<F>(f));
-tuple<typename decay<Args>::type...> w(std::forward<Args>(args)...);
-
      +

      -and executes INVOKE(g, wi...) in a new thread of execution. -These objects shall be destroyed when the new thread of execution completes. -Any return value from g is ignored. -If f terminates with an uncaught exception, std::terminate() shall be called. -If the evaluation of INVOKE(g, wi...) terminates -with an uncaught exception, std::terminate() shall be called [Note: -std::terminate() could be called before entering g. -- end note]. Any -exception thrown before the evaluation of INVOKE has started shall be -catchable in the calling thread. +Note: If this function will be conceptualized, the here proposed +MoveConstructible +requirement can be removed, because this is an implied requirement of +function arguments, see +N2710/[temp.req.impl]/3, last bullet.

      + +

      [ +post San Francisco: +]

      + + +
      +Issue pulled by author prior to review. +
      + +

      [ +2009-07-30 Daniel reopened: +]

      + + +
      +with the absence of concepts, this issue (closed) is valid again and I +suggest to reopen it. +I also revised by proposed resolution based on N2723 wording: +
      + + + +

      Proposed resolution:

      --6- Synchronization: The invocation of the constructor happens before the -invocation of f g. +Change the first sentence of 26.7.5 [numeric.iota]/1:

      + +
      +Requires: T shall meet the requirements of CopyConstructible and +Assignable types, and shall be +convertible to ForwardIterator's value type. [..]
      @@ -20390,357 +13750,412 @@ invocation of f g. + +
      -

      930. Access to std::array data as built-in array type

      -

      Section: 23.3.1 [array] Status: Open - Submitter: Niels Dekker Opened: 2008-11-17 Last modified: 2009-06-01

      -

      View other active issues in [array].

      -

      View all other issues in [array].

      +

      872. move_iterator::operator[] has wrong return type

      +

      Section: 24.5.2.2.12 [move.iter.op.index] Status: Open + Submitter: Doug Gregor Opened: 2008-08-21 Last modified: 2009-07-28

      View all issues with Open status.

      Discussion:

      +

      +move_iterator's operator[] is declared as: +

      + +
      reference operator[](difference_type n) const;
+

      -The Working Draft (N2798) allows access to the elements of -std::array by its data() member function: +This has the same problem that reverse_iterator's operator[] used to +have: if the underlying iterator's operator[] returns a proxy, the +implicit conversion to value_type&& could end up referencing a temporary +that has already been destroyed. This is essentially the same issue that +we dealt with for reverse_iterator in DR 386.

      -
      +

      [ +2009-07-28 Reopened by Alisdair. No longer solved by concepts. +]

      + + -
      23.2.1.4 array::data [array.data]
      -
       T *data();
- const T *data() const;
-
      -
      1. - Returns: elems. -
      -
      +

      Proposed resolution:

      -Unfortunately, the result of std::array::data() cannot be bound -to a reference to a built-in array of the type of array::elems. -And std::array provides no other way to get a reference to -array::elems. -This hampers the use of std::array, for example when trying to -pass its data to a C style API function: +In 24.5.2.1 [move.iterator] and 24.5.2.2.12 [move.iter.op.index], change the declaration of +move_iterator's operator[] to:

      -
       // Some C style API function. 
- void set_path( char (*)[MAX_PATH] );
+
      reference unspecified operator[](difference_type n) const;
+
      
 
- std::array<char,MAX_PATH> path;
- set_path( path.data() );  // error
- set_path( &(path.data()) );  // error
-
      -

      -Another example, trying to pass the array data to an instance of another -C++ class: -

      -
       // Represents a 3-D point in space.
- class three_d_point {
- public:
-   explicit three_d_point(const double (&)[3]); 
- };
+
      Rationale:
      
+
      [
+San Francisco:
+]
      
+
+
+
      
+NAD Editorial, see
+N2777.
+
      
+
 
- const std::array<double,3> coordinates = { 0, 1, 2 };
- three_d_point point1( coordinates.data() );  // error.
- three_d_point point2( *(coordinates.data()) );  // error.
-
      + +
      +

      876. basic_string access operations should give stronger guarantees

      +

      Section: 21.4 [basic.string] Status: Ready + Submitter: Daniel Krügler Opened: 2008-08-22 Last modified: 2009-07-17

      +

      View all other issues in [basic.string].

      +

      View all issues with Ready status.

      +

      Discussion:

      -A user might be tempted to use std::array::elems instead, but -doing so isn't recommended, because std::array::elems is "for -exposition only". Note that Boost.Array users might already use -boost::array::elems, as its documentation doesn't explicitly -state that boost::array::elems is for exposition only: -http://www.boost.org/doc/libs/1_36_0/doc/html/boost/array.html +During the Sophia Antipolis meeting it was decided to split-off some +parts of the +n2647 +("Concurrency modifications for basic_string") +proposal into a separate issue, because these weren't actually +concurrency-related. The here proposed changes refer to the recent +update document +n2668 +and attempt to take advantage of the +stricter structural requirements.

      -I can think of three options to solve this issue: +Indeed there exists some leeway for more guarantees that would be +very useful for programmers, especially if interaction with transactionary +or exception-unaware C API code is important. This would also allow +compilers to take advantage of more performance optimizations, because +more functions can have throw() specifications. This proposal uses the +form of "Throws: Nothing" clauses to reach the same effect, because +there already exists a different issue in progress to clean-up the current +existing "schizophrenia" of the standard in this regard.

      -
      1. -Remove the words "exposition only" from the definition of -std::array::elems, as well as the note saying that "elems is -shown for exposition only." -
      2. -Change the signature of std::array::data(), so that it would -return a reference to the built-in array, instead of a pointer to its -first element. -
      3. -Add extra member functions, returning a reference to the built-in array. -

      -Lawrence Crowl wrote me that it might be better to leave -std::array::elems "for exposition only", to allow alternate -representations to allocate the array data dynamically. This might be -of interest to the embedded community, having to deal with very limited -stack sizes. +Due to earlier support for copy-on-write, we find the following +unnecessary limitations for C++0x:

      + +
        +
      1. +Missing no-throw guarantees: data() and c_str() simply return +a pointer to their guts, which is a non-failure operation. This should +be spelled out. It is also noteworthy to mention that the same +guarantees should also be given by the size query functions, +because the combination of pointer to content and the length is +typically needed during interaction with low-level API. +
        2. +
      2. +Missing complexity guarantees: data() and c_str() simply return +a pointer to their guts, which is guaranteed O(1). This should be +spelled out. +
        3. +
      3. +Missing reading access to the terminating character: Only the +const overload of operator[] allows reading access to the terminator +char. For more intuitive usage of strings, reading access to this +position should be extended to the non-const case. In contrast +to C++03 this reading access should now be homogeneously +an lvalue access. +
        4. +
      +

      -The second option, changing the return type of -std::array::data(), would break backward compatible to current -Boost and TR1 implementations, as well as to the other contiguous -container (vector and string) in a very subtle way. -For example, the following call to std::swap currently swap two -locally declared pointers (data1, data2), for any container -type T that has a data() member function. When -std::array::data() is changed to return a reference, the -std::swap call may swap the container elements instead. +The proposed resolution is split into a main part (A) and a +secondary part (B) (earlier called "Adjunct Adjunct Proposal"). +(B) extends (A) by also making access to index position +size() of the at() overloads a no-throw operation. This was +separated, because this part is theoretically observable in +specifically designed test programs.

      -
       template <typename T>
- void func(T& container1, T& container2)
- {
-   // Are data1 and data2 pointers or references?
-   auto data1 = container1.data();
-   auto data2 = container2.data();
+
      [
+San Francisco:
+]
      
 
-   // Will this swap two local pointers, or all container elements?
-   std::swap(data1, data2);
- }
-
      +

      -The following concept is currently satisfied by all contiguous -containers, but it no longer is for std::array, when -array::data() -is changed to return a reference (tested on ConceptGCC Alpha 7): +We oppose part 1 of the issue but hope to address size() in +issue 877.

      - -
       auto concept ContiguousContainerConcept<typename T>
- {
-   typename value_type = typename T::value_type;
-   const value_type * T::data() const;
- }
-
      -

      -Still it's worth considering having std::array::data() return a -reference, because it might be the most intuitive option, from a user's -point of view. Nicolai Josuttis (who wrote boost::array) -mailed me that he very much prefers this option. +We do not support part B. 4 of the issue because of the breaking API change.

      -Note that for this option, the definition of data() would also -need to be revised for zero-sized arrays, as its return type cannot be a -reference to a zero-sized built-in array. Regarding zero-sized array, -data() could throw an exception. Or there could be a partial -specialization of std::array where data() returns -T* or gets removed. +We support part A. 2 of the issue.

      -Personally I prefer the third option, adding a new member function to -std::array, overloaded for const and non-const access, -returning a reference to the built-in array, to avoid those compatible -issues. I'd propose naming the function std::array::c_array(), -which sounds intuitive to me. Note that boost::array already -has a c_array() member, returning a pointer, but Nicolai told -me that this one is only there for historical reasons. (Otherwise a name -like std::array::native_array() or -std::array::builtin_array() would also be fine with me.) -According to my proposed resolution, a zero-sized std::array does not need -to have c_array(), while it is still required to have -data() functions. +On support part A. 3 of the issue:

      +
      +Pete's broader comment: now that we know that basic_string will be a +block of contiguous memory, we should just rewrite its specification +with that in mind. The expression of the specification will be simpler +and probably more correct as a result. +
      +

      [ -Post Summit: +2009-07 Frankfurt ]

      +

      +Move proposed resolution A to Ready. +

      +

      [ +Howard: Commented out part B. +]

      + +
      + + + +

      Proposed resolution:

      +
        +
      1. +
          +
        1. +

          In 21.4.4 [string.capacity], just after p. 1 add a new paragraph: +

          +
          +Throws: Nothing. +
          + +
          2. +
        2. +

          +In 21.4.5 [string.access] replace p. 1 by the following 4 paragraghs: +

          + +
          +

          +Requires: pos ≤ size(). +

          +

          +Returns: If pos < size(), returns *(begin() + pos). Otherwise, returns +a reference to a charT() that shall not be modified. +

          +

          +Throws: Nothing. +

          +

          +Complexity: Constant time. +

          +
          +
          3. +
        3. +

          +In 21.4.7.1 [string.accessors] replace the now common returns +clause of c_str() and data() by the following three paragraphs: +

          +

          -Alisdair: Don't like p4 suggesting implementation-defined behaviour. +Returns: A pointer p such that p+i == &operator[](i) for each i +in [0, size()].

          -Walter: What about an explicit conversion operator, instead of adding -the new member function? +Throws: Nothing.

          -Alisdair: Noodling about: +Complexity: Constant time.

          -
          template<size_t N, ValueType T>
-struct array
-{
-  T elems[N];
-
-// fantasy code starts here
+
          +
          4. +
        +
        2. -// crazy decltype version for grins only -//requires True<(N>0)> -//explict operator decltype(elems) & () { return elems; } +
      -// conversion to lvalue ref -requires True<(N>0)> -explict operator T(&)[N] () & { return elems; } -// conversion to const lvalue ref -requires True<(N>0)> -explict operator const T(&)[N] () const & { return elems; } -// conversion to rvalue ref using ref qualifiers -requires True<(N>0)> -explict operator T(&&)[N] () && { return elems; } -// fantasy code ends here -explicit operator bool() { return true; } -}; - +
      +

      879. Atomic load const qualification

      +

      Section: 29 [atomics] Status: Open + Submitter: Alexander Chemeris Opened: 2008-08-24 Last modified: 2009-07-17

      +

      View other active issues in [atomics].

      +

      View all other issues in [atomics].

      +

      View all issues with Open status.

      +

      Discussion:

      -This seems legal but odd. Jason Merrill says currently a CWG issue 613 -on the non-static data member that fixes the error that current G++ -gives for the non-explicit, non-conceptualized version of this. Verdict -from human compiler: seems legal. +The atomic_address type and atomic<T*> specialization provide atomic +updates to pointers. However, the current specification requires +that the types pointer be to non-const objects. This restriction +is unnecessary and unintended.

      + +

      [ +Summit: +]

      + +
      +Move to review. Lawrence will first check with Peter whether the +current examples are sufficient, or whether they need to be expanded to +include all cases. +
      + +

      [ +2009-07 Frankfurt +]

      + + +

      -Some grumbling about zero-sized arrays being allowed and supported. +Lawrence will handle all issues relating to atomics in a single paper.

      -Walter: Would this address the issue? Are we inclined to go this route? +LWG will defer discussion on atomics until that paper appears.

      -Alan: What would usage look like? +Move to Open.

      -
      // 3-d point in space
-struct three_d_point
-{
-  explicit three_d_point(const double (&)[3]);
-};
-
-void sink(double*);
+
      -const std::array<double, 3> coordinates = { 0, 1, 2 }; -three_d_point point1( coordinates.data() ); //error -three_d_point point2( *(coordinates.data()) ); // error -three_d_point point3( coordinates ); // yay! -sink(cooridinates); // error, no conversion -
      +

      Proposed resolution:

      -Recommended Open with new wording. Take the required clause and add the -explicit conversion operators, not have a typedef. At issue still is use -decltype or use T[N]. In favour of using T[N], even though use of -decltype is specially clever. +Add const qualification to the pointer values of the atomic_address +and atomic<T*> specializations. E.g.

      - +
      typedef struct atomic_address {
+   void store(const void*, memory_order = memory_order_seq_cst) volatile;
+   void* exchange( const void*, memory_order = memory_order_seq_cst) volatile;
+   bool compare_exchange( const void*&, const void*,
+                          memory_order, memory_order) volatile;
+   bool compare_exchange( const void*&, const void*,
+                          memory_order = memory_order_seq_cst ) volatile;
+   void* operator=(const void*) volatile;
+} atomic_address;
 
-
      [
-Post Summit, further discussion in the thread starting with c++std-lib-23215.
-]
      
+void atomic_store(volatile atomic_address*, const void*);
+void atomic_store_explicit(volatile atomic_address*, const void*,
+                          memory_order);
+void* atomic_exchange(volatile atomic_address*, const void*);
+void* atomic_exchange_explicit(volatile atomic_address*, const void*,
+                              memory_order);
+bool atomic_compare_exchange(volatile atomic_address*,
+                            const void**, const void*);
+bool atomic_compare_exchange_explicit(volatile atomic_address*,
+                                     const void**, const void*,
+                                     memory_order, memory_order);
+
      -

      Proposed resolution:

      + +
      +

      880. Missing atomic exchange parameter

      +

      Section: 29 [atomics] Status: Open + Submitter: Lawrence Crowl Opened: 2008-08-24 Last modified: 2009-07-17

      +

      View other active issues in [atomics].

      +

      View all other issues in [atomics].

      +

      View all issues with Open status.

      +

      Duplicate of: 942

      +

      Discussion:

      -Add to the template definition of array, 23.3.1 [array]/3: +The atomic_exchange and atomic_exchange_explicit functions seem to +be inconsistently missing parameters.

      -
      -
      
-typedef T c_array_type[N];
-c_array_type & c_array() &;
-c_array_type && c_array() &&;
-const c_array_type & c_array() const &;
-
-
      -
      +

      [ +Post Summit: +]

      + +

      -Add the following subsection to 23.3.1 [array], after 23.3.1.4 [array.data]: +Lawrence: Need to write up a list for Pete with details. +

      +

      +Detlef: Should not be New, we already talked about in Concurrency group.

      +

      +Recommend Open. +

      +
      + +

      [ +2009-07 Frankfurt +]

      + -
      -
      23.2.1.5 array::c_array [array.c_array]
      - 
      
-c_array_type & c_array() &;
-c_array_type && c_array() &&;
-const c_array_type & c_array() const &;
-

      -Returns: elems. +Lawrence will handle all issues relating to atomics in a single paper. +

      +

      +LWG will defer discussion on atomics until that paper appears. +

      +

      +Move to Open.

      -
      + +

      Proposed resolution:

      -Add to Zero sized arrays 23.3.1.6 [array.zero]: +Add the appropriate parameters. For example,

      -
      -4. The presence of c_array_type and c_array() and -their semantics are implementation defined, for a zero-sized array. -
      +
      bool atomic_exchange(volatile atomic_bool*, bool);
+bool atomic_exchange_explicit(volatile atomic_bool*, bool, memory_order);
+
      -

      931. type trait extent<T, I>

      -

      Section: 20.6.4.3 [meta.unary.prop] Status: Tentatively Ready - Submitter: Yechezkel Mett Opened: 2008-11-04 Last modified: 2009-03-09

      -

      View other active issues in [meta.unary.prop].

      -

      View all other issues in [meta.unary.prop].

      -

      View all issues with Tentatively Ready status.

      +

      881. shared_ptr conversion issue

      +

      Section: 20.8.10.2.1 [util.smartptr.shared.const] Status: Ready + Submitter: Peter Dimov Opened: 2008-08-30 Last modified: 2009-07-17

      +

      View other active issues in [util.smartptr.shared.const].

      +

      View all other issues in [util.smartptr.shared.const].

      +

      View all issues with Ready status.

      Discussion:

      -The draft (N2798) says in 20.6.4.3 [meta.unary.prop] Table 44: +We've changed shared_ptr<Y> to not convert to shared_ptr<T> when Y* +doesn't convert to T* by resolving issue 687. This only fixed the +converting copy constructor though. +N2351 +later added move support, and +the converting move constructor is not constrained.

      + +

      [ +San Francisco: +]

      + +
      - - - - - - - -
      Table 44 -- Type property queries
      TemplateValue
      -template <class T, unsigned I = 0> struct extent; - -If T is not an array type (8.3.4), or if it has rank less than -I, or if I is 0 -and T has type "array of unknown bound of U", then 0; otherwise, the -size of the I'th dimension of T -
      +We might be able to move this to NAD, Editorial once shared_ptr is +conceptualized, but we want to revisit this issue to make sure.
      -

      -Firstly it isn't clear from the wording if I is 0-based or 1-based -("the I'th dimension" sort of implies 1-based). From the following -example it is clear that the intent is 0-based, in which case it -should say "or if it has rank less than or equal to I". -

      -

      -Sanity check: -

      -

      -The example says assert((extent<int[2], 1>::value) == 0); -

      -

      -Here the rank is 1 and I is 1, but the desired result is 0. -

      -

      [ -Post Summit: +2009-07 Frankfurt ]

      -Do not use "size" or "value", use "bound". Also, move the -cross-reference to 8.3.4 to just after "bound". +Moved to Ready.

      -Recommend Tentatively Ready. +This issue now represents the favored format for specifying constrained templates.

      @@ -20748,33 +14163,26 @@ Recommend Tentatively Ready.

      Proposed resolution:

      -In Table 44 of 20.6.4.3 [meta.unary.prop], third row, column "Value", -change the cell content: +We need to change the Requires clause of the move constructor:

      +
      shared_ptr(shared_ptr&& r); 
+template<class Y> shared_ptr(shared_ptr<Y>&& r); 
+
      - - - - - - - -
      Table 44 -- Type property queries
      TemplateValue
      -template <class T, unsigned I = 0> struct extent; - -If T is not an array type (8.3.4), or if it has rank less than - or equal to I, or if I is 0 -and T has type "array of unknown bound of U", then 0; otherwise, the -size bound (8.3.4) of the I'th dimension of T, -where indexing of I is zero-based. -
      +Requires Remarks: For the second constructor Y* shall be +convertible to T*. + +The second constructor shall not participate in overload resolution +unless Y* is convertible to T*. + +
      -

      [ -Wording supplied by Daniel. -]

      - +

      +in order to actually make the example in 687 compile +(it now resolves to the move constructor). +

      @@ -20782,52 +14190,89 @@ Wording supplied by Daniel.
      -

      932. unique_ptr(pointer p) for pointer deleter types

      -

      Section: 20.8.12.2.1 [unique.ptr.single.ctor] Status: Tentatively Ready - Submitter: Howard Hinnant Opened: 2008-11-26 Last modified: 2009-03-12

      -

      View other active issues in [unique.ptr.single.ctor].

      -

      View all other issues in [unique.ptr.single.ctor].

      -

      View all issues with Tentatively Ready status.

      +

      883. swap circular definition

      +

      Section: 23 [containers] Status: Ready + Submitter: Alisdair Meredith Opened: 2008-09-10 Last modified: 2009-07-17

      +

      View other active issues in [containers].

      +

      View all other issues in [containers].

      +

      View all issues with Ready status.

      Discussion:

      -

      Addresses US 79

      +

      +Note in particular that Table 90 "Container Requirements" gives +semantics of a.swap(b) as swap(a,b), yet for all +containers we define swap(a,b) to call a.swap(b) - a +circular definition. +

      + +

      [ +San Francisco: +]

      -

      -20.8.12.2.1 [unique.ptr.single.ctor]/5 no longer requires for D -not to be a pointer type. I believe this restriction was accidently removed -when we relaxed the completeness reuqirements on T. The restriction -needs to be put back in. Otherwise we have a run time failure that could -have been caught at compile time: -

      -
      {
-unique_ptr<int, void(*)(void*)> p1(malloc(sizeof(int)));  // should not compile
-}  // p1.~unique_ptr() dereferences a null function pointer
-unique_ptr<int, void(*)(void*)> p2(malloc(sizeof(int)), free);  // ok
-
      +
      +Robert to propose a resolution along the lines of "Postcondition: "a = +b, b = a" This will be a little tricky for the hash containers, since +they don't have operator==. +

      [ -Post Summit: +Post Summit Anthony Williams provided proposed wording. +]

      + + +

      [ +2009-07 Frankfurt ]

      -Recommend Tentatively Ready. +Moved to Ready with minor edits (which have been made).

      Proposed resolution:

      -Change 20.8.12.2.1 [unique.ptr.single.ctor]/5: +In table 80 in section 23.2.1 [container.requirements.general], +replace the postcondition of a.swap(b) with the following:

      -
      unique_ptr(pointer p);
-
      -Requires: D shall not be a pointer type (diagnostic required). -D shall be default constructible, and that construction shall not throw an exception. + + + + + + + + + + + + + + + + + + + + + + + +
      Table 80 -- Container requirements
      ExpressionReturn typeOperational semanticsAssertion/note pre-/post-conidtionComplexity
      ...............
      a.swap(b);void swap(a,b) +Exchange the contents of a and b.(Note A)
      + +

      +Remove the reference to swap from the paragraph following the table. +

      + +
      +Notes: the algorithms swap(), equal() and +lexicographical_compare() are defined in Clause 25. ...
      @@ -20835,192 +14280,184 @@ Change 20.8.12.2.1 [unique.ptr.single.ctor]/5:
      -

      933. Unique_ptr defect

      -

      Section: 20.8.12.2.5 [unique.ptr.single.modifiers] Status: Open - Submitter: Alisdair Meredith Opened: 2008-11-27 Last modified: 2009-05-23

      -

      View other active issues in [unique.ptr.single.modifiers].

      -

      View all other issues in [unique.ptr.single.modifiers].

      +

      885. pair assignment

      +

      Section: 20.3.3 [pairs] Status: Open + Submitter: Alisdair Meredith Opened: 2008-09-15 Last modified: 2009-07-17

      +

      View other active issues in [pairs].

      +

      View all other issues in [pairs].

      View all issues with Open status.

      Discussion:

      -

      -If we are supporting stateful deleters, we need an overload for -reset that -takes a deleter as well. -

      - -
      void reset( pointer p, deleter_type d);
+
      20.2.3 pairs
+Missing assignemnt operator:
+template<class U , class V>
+  requires CopyAssignable<T1, U> && CopyAssignable<T2, V>
+    pair& operator=(pair<U , V> const & p );
 
      
 
 
      
-We probably need two overloads to support move-only deleters, and
-this
-sounds uncomfortably like the two constructors I have been ignoring
-for
-now...
+Well, that's interesting. This assignment operator isn't in the
+current working paper, either. Perhaps we deemed it acceptable to
+build a temporary of type pair from pair<U, V>, then move-assign
+from that temporary?
+
      
+
      
+It sounds more like an issue waiting to be opened, unless you want to plug
+it now.  As written we risk moving from lvalues.
 
      
 
 
      [
-Batavia (2009-05):
+San Francisco:
 ]
      
 
+
 
      
 
      
-Howard comments that we have the functionality via move-assigment.
+Would be NAD if better ctors fixed it.
 
      
 
      
-Move to Open.
+Related to 811.
 
      
 
      
 
+
      [
+post San Francisco:
+]
      
 
-
      Proposed resolution:
      
-
      
-
      
-
-
-
-
-
-
      
-
      934. duration is missing operator%
      
-
      Section: 20.9.3 [time.duration] Status: Tentatively Ready
- Submitter: Terry Golubiewski Opened: 2008-11-30  Last modified: 2009-05-23
      
-
      View all issues with Tentatively Ready status.
      
-
      Discussion:
      
-
-
      Addresses US 81
      
-
-
      
-duration is missing operator%.  This operator is convenient
-for computing where in a time frame a given duration lies.  A
-motivating example is converting a duration into a "broken-down"
-time duration such as hours::minutes::seconds:
-
      
-
-
      class ClockTime
-{
-    typedef std::chrono::hours hours;
-    typedef std::chrono::minutes minutes;
-    typedef std::chrono::seconds seconds;
-public:
-    hours hours_;
-    minutes minutes_;
-    seconds seconds_;
 
-    template <class Rep, class Period>
-      explicit ClockTime(const std::chrono::duration<Rep, Period>& d)
-        : hours_  (std::chrono::duration_cast<hours>  (d)),
-          minutes_(std::chrono::duration_cast<minutes>(d % hours(1))),
-          seconds_(std::chrono::duration_cast<seconds>(d % minutes(1)))
-          {}
-};
-
      
+
      
+Possibly NAD Editorial, solved by
+N2770.
+
      
 
 
      [
-Summit:
+2009-05-25 Alisdair adds:
 ]
      
 
 
 
      
-Agree except that there is a typo in the proposed resolution. The member
-operators should be operator%=.
+Issue 885 was something I reported while reviewing the library concepts
+documents ahead of San Francisco.  The missing operator was added as part of
+the paper adopted at that meeting
+(N2770)
+and I can confirm this operator is
+present in the current working paper.  I recommend NAD.
 
      
 
 
      [
-Batavia (2009-05):
+2009-07 Frankfurt
 ]
      
 
+
 
      
-We agree with the proposed resolution.
-Move to Tentatively Ready.
+We agree with the intent, but we need to wait for the dust to settle on concepts.
 
      
 
 
+
 
      Proposed resolution:
      
 
      
-Add to the synopsis in 20.9 [time]:
 
      
 
-
      template <class Rep1, class Period, class Rep2>
-  duration<typename common_type<Rep1, Rep2>::type, Period>
-  operator%(const duration<Rep1, Period>& d, const Rep2& s);
-template <class Rep1, class Period1, class Rep2, class Period2>
-  typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
-  operator%(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
-
      
 
-
      
-Add to the synopsis of duration in 20.9.3 [time.duration]:
-
      
 
-
      template <class Rep, class Period = ratio<1>>
-class duration {
-public:
-  ...
-  duration& operator%=(const rep& rhs);
-  duration& operator%=(const duration& d);
-  ...
-};
-
      
 
+
+
      
+
      886. tuple construction
      
+
      Section: 20.5.2.1 [tuple.cnstr] Status: Ready
+ Submitter: Alisdair Meredith Opened: 2008-09-15  Last modified: 2009-07-17
      
+
      View other active issues in [tuple.cnstr].
      
+
      View all other issues in [tuple.cnstr].
      
+
      View all issues with Ready status.
      
+
      Discussion:
      
 
      
-Add to 20.9.3.3 [time.duration.arithmetic]:
+20.5.2.1 [tuple.cnstr]:
 
      
-
-
      
-
      duration& operator%=(const rep& rhs);
-
      
 
      
+Effects: Default initializes each element.
+
      
+
 
      
-Effects: rep_ %= rhs.
+Could be clarified to state each "non-trivial" element.  Otherwise
+we have a conflict with Core deinfition of default initialization -
+trivial types do not get initialized (rather than initialization
+having no effect)
 
      
+
 
      
-Returns: *this.
+I'm going to punt on this one, because it's not an issue that's
+related to concepts. I suggest bringing it to Howard's attention on
+the reflector.
 
      
-
      
 
-
      duration& operator%=(const duration& d);
-
      
+
      [
+San Francisco:
+]
      
+
+
 
      
 
      
-Effects: rep_ %= d.count().
+Text in draft doesn't mean anything, changing to "non-trivial" makes it
+meaningful.
 
      
 
      
-Returns: *this.
+We prefer "value initializes". Present implementations use
+value-initialization. Users who don't want value initialization have
+alternatives.
+
      
+
      
+Request resolution text from Alisdair.
 
      
-
      
-

      -Add to 20.9.3.5 [time.duration.nonmember]: +This issue relates to Issue 868 default construction and value-initialization.

      +
      + +

      [ +2009-05-04 Alisdair provided wording and adds: +]

      -
      -
      template <class Rep1, class Period, class Rep2>
-  duration<typename common_type<Rep1, Rep2>::type, Period>
-  operator%(const duration<Rep1, Period>& d, const Rep2& s);
-

      -Requires: Rep2 shall be implicitly convertible to CR(Rep1, Rep2) and -Rep2 shall not be an instantiation of duration. Diagnostic required. +Note: This IS a change of semantic from TR1, although one the room agreed +with during the discussion. To preserve TR1 semantics, this would have been +worded:

      +
      requires DefaultConstructible<Types>... tuple();
+
      +
      +-2- Effects: Default-initializes each non-trivial element. +
      +
      + + +
      + +

      [ +2009-07 Frankfurt +]

      + + +
      +Move to Ready. +
      + + + +

      Proposed resolution:

      -Returns: duration<CR, Period>(d) %= s. +Change p2 in Construction 20.5.2.1 [tuple.cnstr]:

      -
      -
      template <class Rep1, class Period1, class Rep2, class Period2>
-  typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
-  operator%(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+
      requires DefaultConstructible<Types>... tuple();
 
      
 
      
 
      
-Returns: common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type(lhs) %= rhs.
+-2- Effects: Default Value-initializes each element.
 
      
 
      
-
 
      
 
 
@@ -21029,234 +14466,256 @@ Add to 20.9.3.5 [time.duration.nonmember]:
 
 
 
      
-
      935. clock error handling needs to be specified
      
-
      Section: 20.9.5 [time.clock] Status: Open
- Submitter: Beman Dawes Opened: 2008-11-24  Last modified: 2009-05-23
      
+
      887. issue with condition::wait_...
      
+
      Section: 30.5.1 [thread.condition.condvar] Status: Open
+ Submitter: Lawrence Crowl Opened: 2008-09-15  Last modified: 2009-07-26
      
+
      View other active issues in [thread.condition.condvar].
      
+
      View all other issues in [thread.condition.condvar].
      
 
      View all issues with Open status.
      
 
      Discussion:
      
 
      
-Each of the three clocks specified in Clocks 20.9.5 [time.clock]
-provides the member function:
+The Posix/C++ working group has identified an inconsistency between
+Posix and the C++ working draft in that Posix requires the clock to be
+identified at creation, whereas C++ permits identifying the clock at the
+call to wait.  The latter cannot be implemented with the former.
 
      
 
-
      static time_point now();
-
      
+
      [
+San Francisco:
+]
      
 
+
+
      
 
      
-The semantics specified by Clock requirements 20.9.1 [time.clock.req]
-make no mention of error handling. Thus the function may throw bad_alloc
-or an implementation-defined exception (17.6.4.10 [res.on.exception.handling]
-paragraph 4).
+Howard recommends NAD with the following explanation:
 
      
 
 
      
-Some implementations of these functions on POSIX, Windows, and
-presumably on other operating systems, may fail in ways only detectable
-at runtime. Some failures on Windows are due to supporting chipset
-errata and can even occur after successful calls to a clock's now()
-function.
+The intent of the current wording is for the condtion_variable::wait_until
+be able to handle user-defined clocks as well as clocks the system knows about.
+This can be done by providing overloads for the known clocks, and another
+overload for unknown clocks which synchs to a known clock before waiting.
+For example:
+
      
+
+
      template <class Duration>
+bool
+condition_variable::wait_until(unique_lock<mutex>& lock,
+                               const chrono::time_point<chrono::system_clock, Duration>& abs_time)
+{
+    using namespace chrono;
+    nanoseconds d = __round_up<nanoseconds>(abs_time.time_since_epoch());
+    __do_timed_wait(lock.mutex()->native_handle(), time_point<system_clock, nanoseconds>(d));
+    return system_clock::now() < abs_time;
+}
+
+template <class Clock, class Duration>
+bool
+condition_variable::wait_until(unique_lock<mutex>& lock,
+                               const chrono::time_point<Clock, Duration>& abs_time)
+{
+    using namespace chrono;
+    typename Clock::time_point  c_entry = Clock::now();
+    system_clock::time_point    s_entry = system_clock::now();
+    nanoseconds dn = __round_up<nanoseconds>(abs_time.time_since_epoch() -
+                                              c_entry.time_since_epoch());
+    __do_timed_wait(lock.mutex()->native_handle(), s_entry + dn);
+    return Clock::now() < abs_time;
+}
+
      
+
+
      
+In the above example, system_clock is the only clock which the underlying
+condition variable knows how to deal with.  One overload just passes that clock
+through.  The second overload (approximately) converts the unknown clock into
+a system_clock  time_point prior to passing it down to the native
+condition variable.
 
      
 
 
      
-These functions are used in cases where exceptions are not appropriate
-or where the specifics of the exception or cause of error need to be
-available to the user. See
-N2828,
-Library Support for hybrid error
-handling (Rev 1), for more specific discussion of use cases. Thus some change in
-the interface of now is required.
+On Posix systems vendors are free to add implementation defined constructors which
+take a clock.  That clock can be stored in the condition_variable, and converted
+to (or not as necessary) as shown above.
 
      
 
 
      
-The proposed resolution has been implemented in the Boost version of the
-chrono library. No problems were encountered.
+If an implementation defined constructor takes a clock (for example), then part
+of the semantics for that implementation defined ctor might include that a
+wait_until using a clock other than the one constructed with results
+in an error (exceptional condition) instead of a conversion to the stored clock.
+Such a design is up to the vendor as once an implementation defined ctor is used,
+the vendor is free to specifiy the behavior of waits and/or notifies however
+he pleases (when the cv is constructed in an implementation defined manner).
 
      
+
      
 
 
      [
-Batavia (2009-05):
+Post Summit:
 ]
      
 
+
 
      
 
      
-We recommend this issue be deferred until the next Committee Draft
-has been issued and the prerequisite paper has been accepted.
+"POSIX people will review the proposed NAD resolution at their upcoming NY
+meeting.
 
      
+
 
      
-Move to Open.
+See the minutes at: http://wiki.dinkumware.com/twiki/bin/view/Posix/POSIX-CppBindingWorkingGroupNewYork2009.
 
      
 
      
 
+
      [
+2009-07 Frankfurt
+]
      
 
-
      Proposed resolution:
      
+
+
      
+Move to NAD.
+
      
+
+
      [
+2009-07-18 Detlef reopens the issue:
+]
      
+
+
+
      
 
      
-Accept the proposed wording of
-N2828,
-Library Support for hybrid error handling (Rev 1).
+On Friday afternoon in Frankfurt is was decided that 887 is NAD.
+This decision was mainly based on a sample implementation presented
+by Howard that implemented one clock on top of another.
+Unfortunately this implementation doesn't work for the probably most
+important case where a system has a monotonic clock and a real-time
+clock (or "wall time" clock):
 
      
-
 
      
-Change Clock requirements 20.9.1 [time.clock.req] as indicated:
+If the underlying "system_clock" is a monotonic clock, and
+the program waits on the real-time clock, and the real-time clock
+is set forward, the wait will unblock too late.
 
      
 
-
      
 
      
--2- In Table 55 C1 and C2 denote clock types. t1 and
-t2 are values returned by C1::now() where the call 
-returning t1 happens before (1.10) the call returning t2 and
-both of these calls happen before C1::time_point::max().
-ec denotes an object of type error_code 
-(19.5.2.2 [syserr.errcode.overview]).
+If the underlying "system_clock" is a real-time clock, and the
+program waits on the monotonic clock, and the real-time clock
+is set back, the wait again will unblock too late.
 
      
 
-
-
-
-
-
+
      
+Sorry that I didn't remember this on Friday, but it was Friday
+afternoon after a busy week...
+
      
 
-
-
-
-
-
+
      
+So as the decision was made on a wrong asumption, I propose to re-open
+the issue.
+
      
+
 
-
-
-
-
-
+
      [
+2009-07-26 Howard adds:
+]
      
 
-
-
-
-
-
-
      Table 55 -- Clock requirements
      ExpressionReturn typeOperational semantics
      .........
      C1::now()C1::time_pointReturns a time_point object representing the current point in time.
-
      C1::now(ec)C1::time_pointReturns a time_point object representing the current point in time.
-
      
-
      
 
+
      
 
      
-Change Class system_clock 20.9.5.1 [time.clock.system] as indicated:
+Detlef correctly argues that condition_variable::wait_until could
+return "too late" in the context of clocks being adjusted during the wait.  I agree
+with his logic.  But I disagree that this makes this interface unimplementable
+on POSIX.
 
      
 
-
      static time_point now(error_code& ec=throws());
-
      
-
 
      
-Change Class monotonic_clock 20.9.5.2 [time.clock.monotonic] as indicated:
+The POSIX spec also does not guarantee that pthread_cond_timedwait does
+not return "too late" when clocks are readjusted during the wait.  Indeed, the
+POSIX specification lacks any requirements at all concerning how soon
+pthread_cond_timedwait returns after a time out.  This is evidently a
+QOI issue by the POSIX standard.  Here is a quote of the most relevant normative
+text concerning pthread_cond_timedwait found
+here.
 
      
 
-
      static time_point now(error_code& ec=throws());
-
      
+
      
+The pthread_cond_timedwait() function shall be equivalent to
+pthread_cond_wait(), except that an error is returned if the absolute
+time specified by abstime passes (that is, system time equals or exceeds
+abstime) before the condition cond is signaled or broadcasted, or if the
+absolute time specified by abstime has already been passed at the time
+of the call.
+
      
 
 
      
-Change Class high_resolution_clock 20.9.5.3 [time.clock.hires] as indicated:
+I.e. the POSIX specification speaks of the error code returned in case of a time
+out, but not on the timeliness of that return.
 
      
 
-
      static time_point now(error_code& ec=throws());
-
      
-
-
-
-
-
-
-
      
-
      936. Mutex type overspecified
      
-
      Section: 30.4.1 [thread.mutex.requirements] Status: Open
- Submitter: Pete Becker Opened: 2008-12-05  Last modified: 2009-03-22
      
-
      View other active issues in [thread.mutex.requirements].
      
-
      View all other issues in [thread.mutex.requirements].
      
-
      View all issues with Open status.
      
-
      Discussion:
      
 
      
-30.4.1 [thread.mutex.requirements] describes the requirements for a type to be
-a "Mutex type". A Mutex type can be used as the template argument for
-the Lock type that's passed to condition_variable_any::wait (although
-Lock seems like the wrong name here, since Lock is given a different
-formal meaning in 30.4.3 [thread.lock]) and, although the WD doesn't quite say
-so, as the template argument for lock_guard and unique_lock.
+Might this simply be an oversight, or minor defect in the POSIX specification?
 
      
 
 
      
-The requirements for a Mutex type include:
+I do not believe so.  This same section goes on to say in non-normative
+text:
 
      
 
-
        
-
      • 
-m.lock() shall be well-formed and have [described] semantics, including a return type of void.
-
        • 
-
      • 
-m.try_lock() shall be well-formed and have [described] semantics, including a return type of bool.
-
        • 
-
      • 
-m.unlock() shall be well-formed and have [described] semantics, including a return type of void.
-
        • 
-
      
+
      
+For cases when the system clock is advanced discontinuously by an
+operator, it is expected that implementations process any timed wait
+expiring at an intervening time as if that time had actually occurred.
+
      
 
 
      
-Also, a Mutex type "shall not be copyable nor movable".
+Here is non-normative wording encouraging the implementation to ignore an advancing
+underlying clock and subsequently causing an early (spurious) return.  There is
+no wording at all which addresses Detlef's example of a "late return".  With
+pthread_cond_timedwait this would be caused by setting the system clock
+backwards.  It seems reasonable to assume, based on the wording that is already
+in the POSIX spec, that again, the discontinuously changed clock would be ignored
+by pthread_cond_timedwait. 
 
      
 
 
      
-The latter requirement seems completely irrelevant, and the three
-requirements on return types are tighter than they need to be. For
-example, there's no reason that lock_guard can't be instantiated with a
-type that's copyable. The rule is, in fact, that lock_guard, etc. won't
-try to copy objects of that type. That's a constraint on locks, not on
-mutexes. Similarly, the requirements for void return types are
-unnecessary; the rule is, in fact, that lock_guard, etc. won't use any
-returned value. And with the return type of bool, the requirement should
-be that the return type is convertible to bool.
+A noteworthy difference between pthread_cond_timedwait and
+condition_variable::wait_until is that the POSIX spec appears to
+say that ETIMEDOUT should be returned if pthread_cond_timedwait
+returns because of timeout signal, whether or not the system clock was discontinuously
+advanced during the wait.  In contrast condition_variable::wait_until
+always returns:
 
      
 
-
      [
-Summit:
-]
      
-
+
      Clock::now() < abs_time
+
      
 
-
      
 
      
-Move to open. Related to conceptualization and should probably be tackled as part of that.
+That is, the C++ spec requires that the clock be rechecked (detecting discontinuous
+adjustments during the wait) at the time of return.  condition_variable::wait_until
+may indeed return early or late.  But regardless it will return a value
+reflecting timeout status at the time of return (even if clocks have been adjusted).
+Of course the clock may be adjusted after the return value is computed but before the client has
+a chance to read the result of the return.  Thus there are no iron-clad guarantees
+here.
 
      
-
        
-
      • 
-The intention is not only to place a constraint on what types such as
-lock_guard may do with mutex types, but on what any code, including user
-code, may do with mutex types. Thus the constraints as they are apply to
-the mutex types themselves, not the current users of mutex types in the
-standard.
-
        • 
-
      • 
-This is a low priority issue; the wording as it is may be overly
-restrictive but this may not be a real issue.
-
        • 
-
      
-
      
-
-
      [
-Post Summit Anthony adds:
-]
      
 
+
      
+condition_variable::wait_until (and pthread_cond_timedwait)
+is little more than a convenience function for making sure
+condition_variable::wait doesn't hang for an unreasonable amount of
+time (where the client gets to define "unreasonable").  I do not think it
+is in anyone's interest to try to make it into anything more than that.
+
      
 
-
      
 
      
-Section 30.4.1 [thread.mutex.requirements] conflates the
-requirements on a generic Mutex type (including user-supplied mutexes)
-with the requirements placed on the standard-supplied mutex types in an
-attempt to group everything together and save space.
+I maintain that this is a useful and flexible specification in the spirit of
+C++, and is implementable on POSIX.  The implementation technique described above
+is a reasonable approach.  There may also be higher quality approaches.  This
+specification, like the POSIX specification, gives a wide latitude for QOI.
 
      
+
 
      
-When applying concepts to chapter 30, I suggest that the concepts
-Lockable and TimedLockable embody the requirements for
-*use* of a mutex type as required by
-unique_lock/lock_guard/condition_variable_any. These should be
-relaxed as Pete describes in the issue. The existing words in 30.4.1 [thread.mutex.requirements] are requirements on all of
-std::mutex, std::timed_mutex,
-std::recursive_mutex and std::recursive_timed_mutex,
-and should be rephrased as such.
+I continue to recommend NAD, but would not object to a clarifying note regarding
+the behavior of condition_variable::wait_until.  At the moment, I do
+not have good wording for such a note, but welcome suggestions.
 
      
+
 
      
 
 
@@ -21270,128 +14729,142 @@ and should be rephrased as such.
 
 
 
      
-
      938. default_delete<T[]>::operator() should only accept T*
      
-
      Section: 20.8.12.1.2 [unique.ptr.dltr.dflt1] Status: Tentatively Ready
- Submitter: Howard Hinnant Opened: 2008-12-07  Last modified: 2009-05-23
      
-
      View all issues with Tentatively Ready status.
      
+
      889. thread::id comparisons
      
+
      Section: 30.3.1.1 [thread.thread.id] Status: Review
+ Submitter: Lawrence Crowl Opened: 2008-09-15  Last modified: 2009-07-28
      
+
      View all other issues in [thread.thread.id].
      
+
      View all issues with Review status.
      
 
      Discussion:
      
-
      
-Consider:
-
      
 
-
      derived* p = new derived[3];
-std::default_delete<base[]> d;
-d(p);  // should fail
-
      
+
      Addresses UK 324
      
 
 
      
-Currently the marked line is a run time failure.  We can make it a compile
-time failure by "poisoning" op(U*).
+The thread::id type supports the full set of comparison operators.  This
+is substantially more than is required for the associative containers that
+justified them.  Please place an issue against the threads library.
 
      
 
 
      [
-Post Summit:
+San Francisco:
 ]
      
 
 
 
      
-Recommend Review.
+
      
+Would depend on proposed extension to POSIX, or non-standard extension.
+What about hash? POSIX discussing op. POSIX not known to be considering
+support needed for hash, op.
+
      
+
      
+Group expresses support for putting ids in both unordered and ordered containers.
+
      
 
      
 
 
      [
-Batavia (2009-05):
+post San Francisco:
 ]
      
 
-
      
-We agree with the proposed resolution.
-Move to Tentatively Ready.
-
      
-
 
-
      Proposed resolution:
      
+
      
 
      
-Add to 20.8.12.1.2 [unique.ptr.dltr.dflt1]:
+Howard:  It turns out the current working paper
+N2723
+already has hash<thread::id>
+(20.7 [function.objects], 20.7.17 [unord.hash]).  We simply
+overlooked it in the meeting.  It is a good thing we voted in favor of it
+(again). :-)
+
      
+
      
+Recommend NAD.
 
      
 
-
      namespace std {
-  template <class T> struct default_delete<T[]> {
-    void operator()(T*) const;
-  template <class U> void operator()(U*) const = delete;
-};
-}
-
      
+
      
+
+
      [
+Post Summit:
+]
      
 
 
+
      
+Recommend to close as NAD. For POSIX, see if we need to add a function to
+convert pthread_t to integer.
+
      
 
+
      [
+Post Summit, Alisdair adds:
+]
      
 
 
-
      
-
      939. Problem with std::identity and reference-to-temporaries
      
-
      Section: 20.7.6 [identity.operation] Status: Review
- Submitter: Alisdair Meredith Opened: 2008-12-11  Last modified: 2009-06-02
      
-
      View all issues with Review status.
      
-
      Discussion:
      
-
      
-std::identity takes an argument of type T const &
-and returns a result of T const &.
-
      
+
      
 
      
-Unfortunately, this signature will accept a value of type other than T that
-is convertible-to-T, and then return a reference to the dead temporary.  The
-constraint in the concepts version simply protects against returning
-reference-to-void.
+The recommendation for LWG-889/UK-324 is NAD, already specified.
 
      
 
      
-Solutions:
+It is not clear to me that the specification is complete.
 
      
-
      
 
      
-i/  Return-by-value, potentially slicing bases and rejecting non-copyable
-types
+In particular, the synopsis of <functional> in 20.7 [function.objects] does not mention hash< thread::id
+> nor hash< error_code >, although their
+existence is implied by 20.7.17 [unord.hash], p1.
 
      
 
      
-ii/ Provide an additional overload:
+I am fairly uncomfortable putting the declaration for the
+thread_id specialization into <functional> as
+id is a nested class inside std::thread, so it implies
+that <functional> would require the definition of the
+thread class template in order to forward declared
+thread::id and form this specialization.
 
      
-
      template< typename T >
-template operator( U & ) = delete;
-
      
 
      
-This seems closer on intent, but moves beyond the original motivation for
-the operator, which is compatibility with existing (non-standard)
-implementations.
+It seems better to me that the dependency goes the other way around
+(<thread> will more typically make use of
+<functional> than vice-versa) and the
+hash<thread::id> specialization be declared in the
+<thread> header.
 
      
 
      
-iii/ Remove the operator() overload.  This restores the original definition
-of the identity, although now effectively a type_trait rather than part of
-the perfect forwarding protocol.
+I think hash<error_code> could go into either
+<system_error> or <functional> and have no
+immediate preference either way.  However, it should clearly appear in
+the synopsis of one of these two.
 
      
 
      
-iv/ Remove std::identity completely; its original reason to exist is
-replaced with the IdentityOf concept.
+Recommend moving 889 back to open, and tying in a reference to UK-324.
 
      
 
      
-
      
-My own preference is somewhere between (ii) and (iii) - although I stumbled
-over the issue with a specific application hoping for resolution (i)!
-
      
 
 
      [
 Batavia (2009-05):
 ]
      
 
 
      
-
      
-We dislike options i and iii, and option ii seems like overkill.
-If we remove it (option iv), implementers can still provide it under a
-different name.
-
      
-
      
-Move to Open pending wording (from Alisdair) for option iv.
-
      
+Howard observes that thread::id need not be a nested class;
+it could be a typedef for a more visible type.
 
      
 
 
      [
-2009-05-23 Alisdair provided wording for option iv.
+2009-05-24 Alisdair adds:
+]
      
+
+
      
+I do not believe this is correct.  thread::id is explicitly documents as a
+nested class, rather than as an unspecified typedef analogous to an
+iterator.  If the intent is that this is not implemented as a nested class
+(under the as-if freedoms) then this is a novel form of standardese.
+
      
+
+
      [
+2009-07 Frankfurt
+]
      
+
+
+
      
+Decided we want to move hash specialization for thread_id to the thread
+header. Alisdair to provide wording.
+
      
+
+
      [
+2009-07-28 Alisdair provided wording, moved to Review.
 ]
      
 
 
@@ -21399,524 +14872,631 @@ Move to Open pending wording (from Alisdair) for option iv.
 
 
      Proposed resolution:
      
 
      
-Strike 20.2.1 [concept.transform] p3:
+Add to 30.3 [thread.threads], p1 Header <thread> synopsis:
 
      
 
-
      
--4- Note: concept form of the identity type metafunction (20.7.6).
-
      
+
      template <class T> struct hash;
+template <> struct hash<thread::id>;
+
      
 
 
      
-Strike from 20.7 [function.objects] p2:
+Add template specialization below class definition in 30.3.1.1 [thread.thread.id]
 
      
 
-
      // 20.7.6, identity operation:
-template <IdentityOf T> struct identity;
+
      template <>
+struct hash<thread::id> : public unary_function<thread::id, size_t> {
+   size_t operator()(thread::id val) const;
+};
 
      
 
 
      
-Remove 20.7.6 [identity.operation] (whole subclause):
+Extend note in p2 30.3.1.1 [thread.thread.id] with second sentence:
 
      
 
 
      
-
      template <IdentityOf T> struct identity {
-  typedef T type;
+[Note: Relational operators allow thread::id objects to be used
+as keys in associative containers.
+hash template specialization allow thread::id objects to be used as keys
+in unordered containers.
+— end note]
+
      
 
-  requires ReferentType<T>
-     const T& operator()(const T& x) const;
-};
+
      
+Add new paragraph to end of 30.3.1.1 [thread.thread.id]
+
      
 
-requires ReferentType<T>
-  const T& operator()(const T& x) const;
+
      template <> struct hash<thread::id>;
 
      
-
      
--1-  Returns: x
-
      
+
      
+An explicit specializations of the class template hash (20.7.17 [unord.hash])
+shall be provided for the values of type thread::id
+suitable for use as keys in unordered associative containers (23.5 [unord]).
+
      
 
      
 
 
 
 
 
-
 
      
-
      940. std::distance
      
-
      Section: 24.4 [iterator.operations] Status: Tentatively Ready
- Submitter: Thomas Opened: 2008-12-14  Last modified: 2009-05-23
      
-
      View other active issues in [iterator.operations].
      
-
      View all other issues in [iterator.operations].
      
-
      View all issues with Tentatively Ready status.
      
+
      891. std::thread, std::call_once issue
      
+
      Section: 30.3.1.2 [thread.thread.constr], 30.4.5.2 [thread.once.callonce] Status: Open
+ Submitter: Peter Dimov Opened: 2008-09-15  Last modified: 2009-07-17
      
+
      View other active issues in [thread.thread.constr].
      
+
      View all other issues in [thread.thread.constr].
      
+
      View all issues with Open status.
      
 
      Discussion:
      
-
-
      Addresses UK 270
      
-
-
      
-Regarding the std::distance - function, 24.4 [iterator.operations]
-/ 4 says:
-
      
-
      
-Returns the
-number of increments or decrements needed to get from first to last.
-
      
-
      
-This sentence is completely silent about the sign of the return value.
-24.4 [iterator.operations] / 1 gives more information about the
-underlying operations, but
-again no inferences about the sign can be made.
-Strictly speaking, that is taking that sentence literally, I think this
-sentence even implies a positive return value in all cases, as the
-number of increments or decrements is clearly a ratio scale variable,
-with a natural zero bound.
-
      
-
      
-Practically speaking, my implementations did what common sense and
-knowledge based on pointer arithmetic forecasts, namely a positive sign
-for increments (that is, going from first to last by operator++), and a
-negative sign for decrements (going from first to last by operator--).
-
      
-
      
-Here are my two questions:
-
      
-
      
-First, is that paragraph supposed to be interpreted in the way what I
-called 'common sense', that is negative sign for decrements ? I am
-fairly sure that's the supposed behavior, but a double-check here in
-this group can't hurt.
-
      
-
      
-Second, is the present wording (2003 standard version - no idea about
-the draft for the upcoming standard) worth an edit to make it a bit more
-sensible, to mention the sign of the return value explicitly ?
-
      
-
-
      [
-Daniel adds:
-]
      
-
-
-
      
-
      
-My first thought was that resolution 204 would already cover the
-issue report, but it seems that current normative wording is in
-contradiction to that resolution:
-
      
-
 
      
-Referring to
-N2798,
-24.4 [iterator.operations]/ p.4 says:
-
      
-
-
      
-Effects: Returns the number of increments or decrements needed to get
-from first to last.
-
      
-
+I notice that the vararg overloads of std::thread and std::call_once
+(N2723 30.3.1.2 [thread.thread.constr] and 30.4.5.2 [thread.once.callonce]) are no longer specified in terms of
+std::bind; instead, some of the std::bind wording has been inlined into
+the specification.
+
      
 
      
-IMO the part " or decrements" is in contradiction to p. 5 which says
+There are two problems with this.
 
      
-
-
      
-Requires: last shall be reachable from first.
-
      
-
 
      
-because "reachable" is defined in 24.2 [iterator.concepts]/7 as
+First, the specification (and implementation) in terms of std::bind allows, for example:
 
      
 
-
      
-An iterator j is called reachable from an iterator i if and only if
-there is a finite
-sequence of applications of the expression ++i that makes i == j.[..]
-
      
+
      std::thread th( f, 1, std::bind( g ) );
+
      
 
 
      
-Here is wording that would be consistent with this definition of "reachable":
+which executes f( 1, g() ) in a thread. This can be useful. The
+"inlined" formulation changes it to execute f( 1, bind(g) ) in a thread.
 
      
-
 
      
-Change 24.4 [iterator.operations] p4 as follows:
+Second, assuming that we don't want the above, the specification has copied the wording
 
      
 
 
      
-Effects: Returns the number of increments or decrements
-needed to get from first to last.
-
      
-
+INVOKE(func, w1, w2, ..., wN) (20.6.2) shall be a valid
+expression for some values w1, w2, ..., wN
 
      
 
 
      
-Thomas adds more discussion and an alternative view point
-here.
+but this is not needed since we know that our argument list is args; it should simply be
 
      
 
+
      
+INVOKE(func, args...) (20.6.2) shall be a valid expression
+
      
+
 
      [
 Summit:
 ]
      
 
 
 
      
-The proposed wording below was verbally agreed to.  Howard provided.
+Move to open.
 
      
 
 
      [
-Batavia (2009-05):
+Post Summit Anthony provided proposed wording.
+]
      
+
+
+
      [
+2009-07 Frankfurt
 ]
      
 
+
 
      
-
      
-Pete reports that a recent similar change has been made
-for the advance() function.
-
      
-
      
-We agree with the proposed resolution.
-Move to Tentatively Ready.
-
      
+Leave Open. Await decision for thread variadic constructor.
 
      
 
 
+
 
      Proposed resolution:
      
 
      
-Change 24.4 [iterator.operations]:
+Change paragraph 4 of 30.3.1.2 [thread.thread.constr] to:
 
      
 
 
      
-
      template <InputIterator Iter>
-  Iter::difference_type
-  distance(Iter first, Iter last);
-template <RandomAccessIterator Iter>
-  Iter::difference_type distance(Iter first, Iter last);
+
      template <class F> explicit thread(F f);
+template <class F, class ...Args> thread(F&& f, Args&&... args);
 
      
-
 
      
+-4- Requires: F and each Ti in Args
+shall be CopyConstructible if an lvalue and otherwise
+MoveConstructible. INVOKE(f, w1, w2, ..., wN args...)
+(20.6.2) shall be a valid expression for some values w1, w2, ...,
+wN, where N == sizeof...(Args).
+
      
+
      
+
 
      
--4- Effects: Returns the number of increments or decrements
-needed to get from first to last.
-
      
-
      
--5- Requires: last shall be reachable from first.
+Change paragraph 1 of 30.4.5.2 [thread.once.callonce] to:
 
      
-
      
 
-
      template <RandomAccessIterator Iter>
-  Iter::difference_type distance(Iter first, Iter last);
+
      template<class Callable, class ...Args> 
+  void call_once(once_flag& flag, Callable func, Args&&... args);
 
      
-
 
      
-
      
--6- Effects: Returns the number of increments or decrements
-needed to get from first to last.
-
      
-
      
--7- Requires: last shall be reachable from first
-or first shall be reachable from last.
-
      
+-1- Requires: The template parameters Callable> and each
+Ti in Args shall be CopyConstructible if an
+lvalue and otherwise MoveConstructible. INVOKE(func,
+w1, w2, ..., wN args...) (20.6.2) shall be a
+valid expression for some values w1, w2, ..., wN, where
+N == sizeof...(Args).
 
      
-
-
 
      
 
 
 
 
 
-
 
      
-
      941. Ref-qualifiers for assignment operators
      
-
      Section: 17 [library] Status: Open
- Submitter: Niels Dekker Opened: 2008-12-18  Last modified: 2009-05-23
      
-
      View other active issues in [library].
      
-
      View all other issues in [library].
      
-
      View all issues with Open status.
      
+
      893. std::mutex issue
      
+
      Section: 30.4.1.1 [thread.mutex.class] Status: Review
+ Submitter: Peter Dimov Opened: 2008-09-15  Last modified: 2009-07-31
      
+
      View other active issues in [thread.mutex.class].
      
+
      View all other issues in [thread.mutex.class].
      
+
      View all issues with Review status.
      
+
      Duplicate of: 905
      
 
      Discussion:
      
 
      
-The assignment and equality operators = and == are easily confused, just
-because of their visual similarity, and in this case a simple typo can cause
-a serious bug. When the left side of an operator= is an rvalue, it's
-highly unlikely that the assignment was intended by the programmer:
-
      
-
      if ( func() = value )  // Typical typo: == intended!
-
      
-
      
-Built-in types don't support assignment to an rvalue, but unfortunately,
-a lot of types provided by the Standard Library do.
+30.4.1.1 [thread.mutex.class]/27 (in
+N2723)
+says that the behavior is undefined if:
 
      
+
        
+
      • a thread that owns a mutex object calls lock() or
+try_lock() on that object
        • 
+
      
 
      
-Fortunately the language now offers a syntax to prevent a certain member
-function from having an rvalue as *this: by adding a ref-qualifier (&)
-to the member function declaration.  Assignment operators are explicitly
-mentioned as a use case of ref-qualifiers, in "Extending Move Semantics
-To *this (Revision 1)",
-N1821 by Daveed
-Vandevoorde and Bronek Kozicki
+I don't believe that this is right. Calling lock() or try_lock() on a
+locked mutex is well defined in the general case. try_lock() is required
+to fail and return false. lock() is required to either throw an
+exception (and is allowed to do so if it detects deadlock) or to block
+until the mutex is free. These general requirements apply regardless of
+the current owner of the mutex; they should apply even if it's owned by
+the current thread.
 
      
 
      
-Hereby I would like to propose adding ref-qualifiers to all appropriate
-assignment operators in the library.
+Making double lock() undefined behavior probably can be justified (even
+though I'd still disagree with the justification), but try_lock() on a
+locked mutex must fail.
 
      
 
 
      [
-Batavia (2009-05):
+Summit:
 ]
      
 
 
      
-Move to Open.
-We recommend this be deferred until after the next Committee Draft.
-
      
-
-
-
      Proposed resolution:
      
-
      
-A proposed resolution is provided by the paper on this subject,
-N2819,
-Ref-qualifiers for assignment operators of the Standard Library
-
      
-
-
-
-
-
-
      
-
      943. ssize_t undefined
      
-
      Section: 29.5.2 [atomics.types.address] Status: Tentatively Ready
- Submitter: Holger Grund Opened: 2008-12-19  Last modified: 2009-05-23
      
-
      View all issues with Tentatively Ready status.
      
-
      Discussion:
      
 
      
-There is a row in "Table 122 - Atomics for standard typedef types"
-in 29.5.1 [atomics.types.integral] with atomic_ssize_t
-and ssize_t. Unless, I'm missing something ssize_t
-is not defined by the standard.
+Move to open. Proposed resolution:
 
      
+
        
+
      • 
+In 30.4.1 [thread.mutex.requirements] paragraph 12, change the error
+condition for resource_deadlock_would_occur to: "if the implementation
+detects that a deadlock would occur"
+
        • 
+
      • 
+Strike 30.4.1.1 [thread.mutex.class] paragraph 3 bullet 2 "a thread that owns a mutex object
+calls lock() or try_lock() on that object, or"
+
        • 
+
      
+
      
 
 
      [
-Summit:
+2009-07 Frankfurt
 ]
      
 
 
 
      
-Move to review. Proposed resolution: Remove the typedef. Note: ssize_t
-is a POSIX type.
+Move to Review. Alisdair to provide note.
 
      
 
 
      [
-Batavia (2009-05):
+2009-07-31 Alisdair provided note.
 ]
      
 
+
+
+
      Proposed resolution:
      
+
      
+In 30.4.1 [thread.mutex.requirements] paragraph 12 change:
+
      
+
 
      
-We agree with the proposed resolution.
-Move to Tentatively Ready.
+
        
+
      • ...
        • 
+
      • 
+resource_deadlock_would_occur -- if the current thread already owns the mutex and is able 
+to detect it implementation detects that a deadlock would occur.
+
        • 
+
      • ...
        • 
+
      
 
      
 
+
      
+Strike 30.4.1.1 [thread.mutex.class] paragraph 3 bullet 2:
+
      
+
      
+
      
+-3- The behavior of a program is undefined if:
+
      
+
        
+
      • ...
        • 
+
      • 
+a thread that owns a mutex object calls lock() or try_lock() on that object, or
+
        • 
+
      • ...
        • 
+
      
+
      
 
-
      Proposed resolution:
      
 
      
-Remove the row containing ssize_t from Table 119
-"Atomics for standard typedef types" in 29.5.2 [atomics.types.address].
+Add the following note after p3 30.4.1.1 [thread.mutex.class]
 
      
 
+
      
+[Note: a program may deadlock if the thread that owns a mutex
+object calls lock() or try_lock() on that object. If the program can
+detect the deadlock, a resource_deadlock_would_occur error condition may
+be observed. — end note]
+
      
+
+
 
 
 
 
 
      
-
      944. atomic<bool> derive from atomic_bool?
      
-
      Section: 29.5.3 [atomics.types.generic] Status: Open
- Submitter: Holger Grund Opened: 2008-12-19  Last modified: 2009-03-22
      
-
      View all other issues in [atomics.types.generic].
      
+
      896. Library thread safety issue
      
+
      Section: 20.8.10.2 [util.smartptr.shared] Status: Open
+ Submitter: Hans Boehm Opened: 2008-09-16  Last modified: 2009-07-17
      
+
      View other active issues in [util.smartptr.shared].
      
+
      View all other issues in [util.smartptr.shared].
      
 
      View all issues with Open status.
      
 
      Discussion:
      
 
      
-I think it's fairly obvious that atomic<bool> is supposed to be derived
-from atomic_bool (and otherwise follow the atomic<integral> interface),
-though I think the current wording doesn't support this. I raised this
-point along with atomic<floating-point> privately with Herb and I seem
-to recall it came up in the resulting discussion on this list. However,
-I don't see anything on the current libs issue list mentioning this
-problem.
+It is unclear whether shared_ptr is thread-safe in the sense that
+multiple threads may simultaneously copy a shared_ptr.  However this
+is a critical piece of information for the client, and it has significant
+impact on usability for many applications.  (Detlef Vollman thinks it
+is currently clear that it is not thread-safe.  Hans Boehm thinks
+it currently requires thread safety, since the use_count is not an
+explicit field, and constructors and assignment take a const reference
+to an existing shared_ptr.)
+
      
+
+
      
+Pro thread-safety:
+
      
+
      
+Many multi-threaded usages are impossible.  A thread-safe version can
+be used to destroy an object when the last thread drops it, something
+that is often required, and for which we have no other easy mechanism.
+
      
+
      
+Against thread-safety:
+
      
+
      
+The thread-safe version is well-known to be far more expensive, even
+if used by a single thread.  Many applications, including all single-threaded
+ones, do not care.
+
      
+
+
      [
+San Francisco:
+]
      
+
+
+
      
+
      
+Beman: this is a complicated issue, and would like to move this to Open
+and await comment from Peter Dimov; we need very careful and complete
+rationale for any decision we make; let's go slow
+
      
+
      
+Detlef: I think that shared_ptr should not be thread-safe.
+
      
+
      
+Hans: When you create a thread with a lambda, it in some cases makes it
+very difficult for the lambda to reference anything in the heap. It's
+currently ambiguous as to whether you can use a shared_ptr to get at an
+object.
+
      
+
      
+Leave in Open. Detlef will submit an alternative proposed resolution
+that makes shared_ptr explicitly unsafe.
+
      
+
      
+A third option is to support both threadsafe and non-safe share_ptrs,
+and to let the programmer decide which behavior they want.
 
      
 
 
      
-29.5.3 [atomics.types.generic]/3 reads
+Beman:  Peter, do you support the PR?
 
      
 
+
      
+Peter:
+
      
 
      
-There are full specializations over the integral types on the atomic
-class template. For each integral type integral in the second column of
-table 121 or table 122, the specialization atomic<integral> shall be
-publicly derived from the corresponding atomic integral type in the
-first column of the table. These specializations shall have trivial
-default constructors and trivial destructors.
+
      
+Yes, I support the proposed resolution, and I certainly oppose any
+attempts to make shared_ptr thread-unsafe.
+
      
+
      
+I'd mildly prefer if
+
      
+
      
+[Note: This is true in spite of that fact that such functions often
+modify use_count() --end note]
 
      
-
 
      
-Table 121 does not include (atomic_bool, bool),
-so that this should probably be mentioned explicitly in the quoted paragraph.
+is changed to
+
      
+
      
+[Note: This is true in spite of that fact that such functions often
+cause a change in use_count() --end note]
+
      
+
      
+(or something along these lines) to emphasise that use_count() is not,
+conceptually, a variable, but a return value.
 
      
+
      
+
+
      
 
 
      [
-Summit:
+2009-07 Frankfurt
 ]
      
 
 
 
      
-Move to open. Lawrence will draft a proposed resolution. Also, ask
-Howard to fix the title.
+
      
+Vote: Do we want one thread-safe shared pointer or two? If two, one
+would allow concurrent construction and destruction of shared pointers,
+and one would not be thread-safe. If one, then it would be thread-safe.
+
      
+
      
+No concensus on that vote.
+
      
+
      
+Hans to improve wording in consultation with Pete. Leave Open.
+
      
 
      
 
-
      [
-Post Summit Anthony provided proposed wording.
-]
      
-
 
 
 
      Proposed resolution:
      
 
      
-Replace paragraph 3 in 29.5.3 [atomics.types.generic] with
+Make it explicitly thread-safe, in this weak sense, as I believe was intended:
+
      
+
      
+Insert in 20.8.10.2 [util.smartptr.shared], before p5:
 
      
-
 
      
--3- There are full specializations over the integral types on the atomic
-class template. For each integral type integral in the second column of
-table 121 or table 122, the specialization atomic<integral> shall be
-publicly derived from the corresponding atomic integral type in the first
-column of the table.
-In addition, the specialization atomic<bool>
-shall be publicly derived from atomic_bool.
-These specializations shall have trivial default
-constructors and trivial destructors.
+
      
+For purposes of determining the presence of a data race,
+member functions do not modify const shared_ptr and
+const weak_ptr arguments, nor any objects they
+refer to.  [Note: This is true in spite of that fact that such functions often
+cause a change in use_count() --end note]
+
      
 
      
+
      
+On looking at the text, I'm not sure we need a similar disclaimer
+anywhere else, since nothing else has the problem with the modified
+use_count().  I think Howard arrived at a similar conclusion.
+
      
 
 
 
 
 
 
      
-
      945. system_clock::rep not specified
      
-
      Section: 20.9.5.1 [time.clock.system] Status: Tentatively NAD Editorial
- Submitter: Pete Becker Opened: 2008-12-19  Last modified: 2009-05-23
      
-
      View other active issues in [time.clock.system].
      
-
      View all other issues in [time.clock.system].
      
-
      View all issues with Tentatively NAD Editorial status.
      
+
      897. Forward_list issues... Part 2
      
+
      Section: 23.3.3.4 [forwardlist.modifiers] Status: Review
+ Submitter: Howard Hinnant Opened: 2008-09-22  Last modified: 2009-07-18
      
+
      View all issues with Review status.
      
 
      Discussion:
      
 
      
-In 20.9.5.1 [time.clock.system], the declaration of system_clock::rep says "see
-below", but there is nothing below that describes it.
+This issue was split off from 892 at the request of the LWG.
 
      
 
 
      [
-Howard adds:
+San Francisco:
 ]
      
 
 
 
      
 
      
-This note refers to:
+This issue is more complicated than it looks.
 
      
-
-
      
--2- system_clock::duration::min() < system_clock::duration::zero() shall be true.
-
      
-
 
      
-I.e. this is standardeze for "system_clock::rep is signed".
-Perhaps an editorial note along the lines of:
+paragraph 47: replace each (first, last) with (first, last]
+
      
+
      
+add a statement after paragraph 48 that complexity is O(1)
+
      
+
      
+remove the complexity statement from the first overload of splice_after
+
      
+
      
+We may have the same problems with other modifiers, like erase_after.
+Should it require that all iterators in the range (position, last] be
+dereferenceable?
 
      
-
-
      
--2- system_clock::duration::min() < system_clock::duration::zero()
-shall be true. [Note: system_clock::rep shall be signed. -- end note].
 
      
 
 
      
-?
+There are actually 3 issues here:
 
      
 
-
      
-
-
      [
-Batavia (2009-05):
-]
      
+
        
+
      1. 
+
        
+What value should erase_after return?  With list, code often
+looks like:
+
        
+
        for (auto i = l.begin(); i != l.end();)
+{
+    // inspect *i and decide if you want to erase it
+    // ...
+    if (I want to erase *i)
+        i = l.erase(i);
+    else
+        ++i;
+}
+
        
+
        
+I.e. the iterator returned from erase is useful for setting up the
+logic for operating on the next element.  For forward_list this might
+look something like:
+
        
+
        auto i = fl.before_begin();
+auto ip1 = i;
+for (++ip1; ip1 != fl.end(); ++ip1)
+{
+    // inspect *(i+1) and decide if you want to erase it
+    // ...
+    if (I want to erase *(i+1))
+        i = fl.erase_after(i);
+    else
+        ++i;
+    ip1 = i;
+}
+
        
+
        
+In the above example code, it is convenient if erase_after returns
+the element prior to the erased element (range) instead of the element
+after the erase element (range).
+
        
+
        
+Existing practice:
+
        
+
          
+
        • SGI slist returns an iterator referencing the element after the erased range.
          • 
+
        • CodeWarrior slist returns an iterator referencing the element before the erased range.
          • 
+
        
+
        
+There is not a strong technical argument for either solution over the other.
+
        
+
        2. 
 
-
        
-We agree with the direction of the proposed resolution.
-Move to NAD Editorial.
-
        
+
      2. 
+
        
+With all other containers, operations always work on the range
+[first, last) and/or prior to the given position.
+
        
+
        
+With forward_list, operations sometimes work on the range
+(first, last] and/or after the given position.
+
        
+
        
+This is simply due to the fact that in order to operate on
+*first (with forward_list) one needs access to
+*(first-1).  And that's not practical with
+forward_list.  So the operating range needs to start with (first,
+not [first (as the current working paper says). 
+
        
+
        
+Additionally, if one is interested in  splicing the range (first, last),
+then (with forward_list), one needs practical (constant time) access to
+*(last-1) so that one can set the next field in this node to
+the proper value.  As this is not possible with forward_list, one must
+specify the last element of interest instead of one past the last element of
+interest.  The syntax for doing this is to pass (first, last] instead
+of (first, last).
+
        
+
        
+With erase_after we have a choice of either erasing the range
+(first, last] or (first, last).  Choosing the latter
+enables:
+
        
+
        x.erase_after(pos, x.end());
+
        
 
+
        
+With the former, the above statement is inconvenient or expensive due to the lack
+of constant time access to x.end()-1.  However we could introduce:
+
        
 
+
        iterator erase_to_end(const_iterator position);
+
        
 
-
        Proposed resolution:
        
 
        
-Add a note to 20.9.5.1 [time.clock.system], p2:
+to compensate.
 
        
-
        
--2- system_clock::duration::min() < system_clock::duration::zero()
-shall be true. [Note: system_clock::rep shall be signed. -- end note].
-
        
-
 
+
        
+The advantage of the former ((first, last]) for erase_after
+is a consistency with splice_after which uses (first, last]
+as the specified range.  But this either requires the addition of erase_to_end
+or giving up such functionality.
+
        
 
+
        3. 
 
+
      3. 
+As stated in the discussion of 892, and reienforced by point 2 above,
+a splice_after should work on the source range (first, last]
+if the operation is to be Ο(1).  When splicing an entire list x the
+algorithm needs (x.before_begin(), x.end()-1].  Unfortunately x.end()-1
+is not available in constant time unless we specify that it must be.  In order to
+make x.end()-1 available in constant time, the implementation would have
+to dedicate a pointer to it.  I believe the design of
+N2543
+intended a nominal overhead of foward_list of 1 pointer.  Thus splicing
+one entire forward_list into another can not be Ο(1).
+
        4. 
+
      
 
-
      
-
      946. duration_cast improperly specified
      
-
      Section: 20.9.3.7 [time.duration.cast] Status: Tentatively NAD
- Submitter: Pete Becker Opened: 2008-12-20  Last modified: 2009-05-23
      
-
      View other active issues in [time.duration.cast].
      
-
      View all other issues in [time.duration.cast].
      
-
      View all issues with Tentatively NAD status.
      
-
      Discussion:
      
-20.9.3.7 [time.duration.cast]/3:
+
      [
+Batavia (2009-05):
+]
      
 
 
      
-.... All intermediate computations shall be
-carried out in the widest possible representation... .
-
      
-
 
      
-So ignoring
-floating-point types for the moment, all this arithmetic has to be done
-using the implementation's largest integral type, even if both arguments
-use int for their representation. This seems excessive. And it's not at
-all clear what this means if we don't ignore floating-point types.
+We agree with the proposed resolution.
 
      
-
 
      
-This issue is related to 952.
+Move to Review.
 
      
+
      
 
 
      [
-Howard adds:
+2009-07 Frankfurt
 ]
      
 
 
 
      
 
      
-The intent of this remark is that intermediate computations are carried out
-using:
+We may need a new issue to correct splice_after, because it may no
+longer be correct to accept an rvalues as an argument. Merge may be
+affected, too. This might be issue 1133. (Howard: confirmed)
+
      
+
      
+Move this to Ready, but the Requires clause of the second form of
+splice_after should say "(first, last)," not "(first, last]" (there are
+three occurrences). There was considerable discussion on this. (Howard: fixed)
+
      
+
      
+Alan suggested removing the "foward_last<T. Alloc>&& x"
+parameter from the second form of splice_after, because it is redundant.
+PJP wanted to keep it, because it allows him to check for bad ranges
+(i.e. "Granny knots").
+
      
+
      
+We prefer to keep x.
 
      
-
-
      common_type<typename ToDuration::rep, Rep, intmax_t>::type
-
      
-
 
      
-The Remark was intended to be clarifying prose supporting the rather algorithmic description
-of the previous paragraph.  I'm open to suggestions.  Perhaps the entire paragraph
-3 (Remarks) would be better dropped?
+Beman. Whenever we deviate from the customary half-open range in the
+specification, we should add a non-normative comment to the standard
+explaining the deviation. This clarifies the intention and spares the
+committee much confusion in the future.
 
      
-
      
-
-
      [
-Batavia (2009-05):
-]
      
-
-
      
 
      
-We view this as a specific case of issue 952,
-and should be resolved when that issue is resolved.
+Alan to write a non-normative comment to explain the use of fully-closed ranges.
 
      
 
      
-Move to NAD.
+Move to Ready, with the changes described above. (Howard: awaiting note from Alan)
 
      
 
      
 
@@ -21924,318 +15504,287 @@ Move to NAD.
 
 
      Proposed resolution:
      
 
      
+Wording below assumes issue 878 is accepted, but this issue is
+independent of that issue.
 
      
 
-
-
-
-
-
      
-
      947. duration arithmetic: contradictory requirements
      
-
      Section: 20.9.3.5 [time.duration.nonmember] Status: Open
- Submitter: Pete Becker Opened: 2008-12-20  Last modified: 2009-05-23
      
-
      View all other issues in [time.duration.nonmember].
      
-
      View all issues with Open status.
      
-
      Discussion:
      
 
      
-In 20.9.3.5 [time.duration.nonmember], paragraph 8 says that calling
-dur / rep
-when rep is an instantiation of duration requires a diagnostic.
-That's followed by an operator/ that takes two durations.
-So dur1 / dur2 is legal under the second version,
-but requires a diagnostic under the first.
+Change 23.3.3.4 [forwardlist.modifiers]:
 
      
 
-
      [
-Howard adds:
-]
      
-
-
 
      
-Please see the thread starting with c++std-lib-22980 for more information.
-
      
-
-
      [
-Batavia (2009-05):
-]
      
-
+
      iterator erase_after(const_iterator position);
+
      
 
      
-Move to Open, pending proposed wording (and preferably an implementation).
-
      
-
-
-
      Proposed resolution:
      
 
      
+Requires: The iterator following position is dereferenceable.
 
      
-
-
-
-
-
-
      
-
      948. ratio arithmetic tweak
      
-
      Section: 20.4.2 [ratio.arithmetic] Status: Tentatively Ready
- Submitter: Howard Hinnant Opened: 2008-12-26  Last modified: 2009-03-09
      
-
      View other active issues in [ratio.arithmetic].
      
-
      View all other issues in [ratio.arithmetic].
      
-
      View all issues with Tentatively Ready status.
      
-
      Discussion:
      
 
      
-N2800,
-20.4.2 [ratio.arithmetic] lacks a paragraph from the proposal
-N2661:
+Effects: Erases the element pointed to by the iterator following position.
 
      
-
-
      
-
      ratio arithmetic [ratio.arithmetic]
      
-
 
      
-... If the implementation is unable to form the indicated ratio due to
-overflow, a diagnostic shall be issued.
+Returns: An iterator pointing to the element following the one that was erased, or end() if no such 
+element exists
+An iterator equal to position.
 
      
 
      
 
+
+
      iterator erase_after(const_iterator position, const_iterator last);
+
      
+
      
+
      
+Requires: All iterators in the range
+[(position,last)
+are dereferenceable.
+
      
+
      
+Effects: Erases the elements in the range
+[(position,last).
+
      
 
      
-The lack of a diagnostic on compile-time overflow is a significant lack of
-functionality.  This paragraph could be put back into the WP simply editorially.
-However in forming this issue I realized that we can do better than that.  This
-paragraph should also allow alternative formulations which go to extra lengths
-to avoid overflow when possible.  I.e. we should not mandate overflow when the
-implementation can avoid it.
+Returns:  An iterator equal to position last
 
      
+
      
+
      
 
 
      
-For example:
+Change 23.3.3.5 [forwardlist.ops]:
 
      
 
 
      
-
      template <class R1, class R2> struct ratio_multiply {
-  typedef see below} type; 
+
      void splice_after(const_iterator position, forward_list<T,Allocator>&& x);
 
      
-
 
      
-The nested typedef type shall be a synonym for ratio<T1, T2> where
-T1 has the value R1::num * R2::num and T2 has the
-value R1::den * R2::den.
-
      
-
-
      
-
 
      
-Consider the case where intmax_t is a 64 bit 2's complement signed integer,
-and we have:
+Requires: position is before_begin() or a
+dereferenceable iterator in the range [begin(), end)). &x != this.
 
      
-
-
      typedef std::ratio<0x7FFFFFFFFFFFFFFF, 0x7FFFFFFFFFFFFFF0> R1;
-typedef std::ratio<8, 7> R2;
-typedef std::ratio_multiply<R1, R2>::type RT;
-
      
-
 
      
-According to the present formulation the implementaiton will multiply
-0x7FFFFFFFFFFFFFFF * 8 which will result in an overflow and subsequently
-require a diagnostic.
+Effects: Inserts the contents of x after position, and
+x becomes empty. Pointers and references to 
+the moved elements of x now refer to those same elements but as members of *this.
+Iterators referring to the moved elements will continue to refer to their elements,
+but they now behave as iterators into *this, not into x. 
 
      
-
 
      
-However if the implementation is first allowed to divde 0x7FFFFFFFFFFFFFFF
-by 7 obtaining 0x1249249249249249 / 1 and divide
-8 by 0x7FFFFFFFFFFFFFF0 obtaining 1 / 0x0FFFFFFFFFFFFFFE,
-then the exact result can then be computed without overflow:
+Throws: Nothing. 
 
      
-
-
      [0x7FFFFFFFFFFFFFFF/0x7FFFFFFFFFFFFFF0] * [8/7] = [0x1249249249249249/0x0FFFFFFFFFFFFFFE]
-
      
-
 
      
-Example implmentation which accomplishes this:
+Complexity: Ο(1) Ο(distance(x.begin(), x.end()))
 
      
-
-
      template <class R1, class R2>
-struct ratio_multiply
-{
-private:
-    typedef ratio<R1::num, R2::den> _R3;
-    typedef ratio<R2::num, R1::den> _R4;
-public:
-    typedef ratio<__ll_mul<_R3::num, _R4::num>::value,
-                  __ll_mul<_R3::den, _R4::den>::value> type;
-};
-
      
-
-
      [
-Post Summit:
-]
      
-
-
-
      
-Recommend Tentatively Ready.
 
      
 
+
      ...
      
 
-
-
-
      Proposed resolution:
      
+
      void splice_after(const_iterator position, forward_list<T,Allocator>&& x, 
+                  const_iterator first, const_iterator last);
+
      
+
      
+
      
+Requires: position is before_begin() or a
+dereferenceable iterator in the range [begin(), end)).
+(first,last) is a valid range in
+x, and all iterators in the range
+(first,last) are dereferenceable.
+position is not an iterator in the range (first,last).
+
      
+
      
+Effects: Inserts elements in the range (first,last)
+after position and removes the elements from x.
+Pointers and references to the moved elements of x now refer to
+those same elements but as members of *this. Iterators
+referring to the moved elements will continue to refer to their
+elements, but they now behave as iterators into *this, not into
+x.
+
      
 
      
-Add a paragraph prior to p1 in 20.4.2 [ratio.arithmetic]:
+Complexity: Ο(1).
 
      
+
      
 
-
      
-Implementations may use other algorithms to compute the indicated ratios to avoid overflow. 
-If overflow occurs, a diagnostic shall be issued.
 
      
 
 
 
 
 
+
 
      
-
      949. owner_less
      
-
      Section: 20.8.13.4 [util.smartptr.ownerless] Status: Tentatively Ready
- Submitter: Thomas Plum Opened: 2008-12-30  Last modified: 2009-03-10
      
-
      View all issues with Tentatively Ready status.
      
+
      900. stream move-assignment
      
+
      Section: 27.9.1.8 [ifstream.assign] Status: Open
+ Submitter: Niels Dekker Opened: 2008-09-20  Last modified: 2009-07-26
      
+
      View all issues with Open status.
      
 
      Discussion:
      
 
      
-20.8.13.4 [util.smartptr.ownerless] (class template owner_less) says that 
-operator()(x,y) shall return x.before(y).
+It
+appears that we have an issue similar to issue 675 regarding the move-assignment of
+stream types. For example, when assigning to an std::ifstream,
+ifstream1, it seems preferable to close the file originally held by
+ifstream1:
 
      
+
+
      ifstream1 = std::move(ifstream2); 
+
      
+
 
      
-However, shared_ptr and weak_ptr have an owner_before() but not a
-before(), and there's no base class to provide a missing before().
+The current Draft
+(N2723)
+specifies that the move-assignment of
+stream types like ifstream has the same effect as a swap:
 
      
+
+
      
 
      
-Being that the class is named  owner_less , I'm guessing that
-"before()" should be "owner_before()", right?
+Assign and swap 27.9.1.8 [ifstream.assign]
 
      
+
      basic_ifstream& operator=(basic_ifstream&& rhs); 
+
      
+
      
+Effects: swap(rhs).
+
      
+
      
 
 
      [
-Herve adds:
+Batavia (2009-05):
 ]
      
 
-
 
      
-Agreed with the typo, it should be "shall return x.owner_before(y)".
+
      
+Howard agrees with the analysis and the direction proposed.
+
      
+
      
+Move to Open pending specific wording to be supplied by Howard.
+
      
 
      
 
 
      [
-Post Summit:
+2009-07 Frankfurt:
 ]
      
 
 
 
      
-Recommend Tentatively Ready.
+Howard is going to write wording.
 
      
 
+
      [
+2009-07-26 Howard provided wording.
+]
      
+
+
 
 
 
      Proposed resolution:
      
+
 
      
-Change 20.8.13.4 [util.smartptr.ownerless] p2:
+Change 27.8.1.2 [stringbuf.assign]/1:
 
      
 
+
      basic_stringbuf& operator=(basic_stringbuf&& rhs);
+
      
 
      
--2- operator()(x,y) shall return
-x.owner_before(y). [Note: ...
+-1- Effects: swap(rhs).
+After the move assignment *this reflects the same observable
+state it would have if it had been move constructed from rhs
+(27.8.1.1 [stringbuf.cons]).
+
+
      
 
      
 
-
-
-
-
-
      
-
      950. unique_ptr converting ctor shouldn't accept array form
      
-
      Section: 20.8.12.2.1 [unique.ptr.single.ctor] Status: Tentatively Ready
- Submitter: Howard Hinnant Opened: 2009-01-07  Last modified: 2009-05-23
      
-
      View other active issues in [unique.ptr.single.ctor].
      
-
      View all other issues in [unique.ptr.single.ctor].
      
-
      View all issues with Tentatively Ready status.
      
-
      Discussion:
      
 
      
-unique_ptr's of array type should not convert to
-unique_ptr's which do not have an array type.
+Change 27.8.2.2 [istringstream.assign]/1:
 
      
 
-
      struct Deleter
-{
-   void operator()(void*) {}
-};
-
-int main()
-{
-   unique_ptr<int[], Deleter> s;
-   unique_ptr<int, Deleter> s2(std::move(s));  // should not compile
-}
-
      
-
-
      [
-Post Summit:
-]
      
-
-
+
      basic_istringstream& operator=(basic_istringstream&& rhs);
+
      
 
      
+-1- Effects: swap(rhs).
+Move assigns the base and members of *this with the respective
+base and members of rhs.
+
+
      
+
      
+
 
      
-Walter: Does the "diagnostic required" apply to both arms of the "and"?
-
      
-
      
-Tom Plum: suggest to break into several sentences
+Change 27.8.3.2 [ostringstream.assign]/1:
 
      
+
+
      basic_ostringstream& operator=(basic_ostringstream&& rhs);
+
      
+
      
+-1- Effects: swap(rhs).
+Move assigns the base and members of *this with the respective
+base and members of rhs.
+
+
      
+
      
+
 
      
-Walter: suggest "comma" before the "and" in both places
+Change 27.8.5.1 [stringstream.assign]/1:
 
      
+
+
      basic_stringstream& operator=(basic_stringstream&& rhs);
+
      
+
      
+-1- Effects: swap(rhs).
+Move assigns the base and members of *this with the respective
+base and members of rhs.
+
+
      
+
      
+
 
      
-Recommend Review.
+Change 27.9.1.3 [filebuf.assign]/1:
 
      
+
+
      basic_filebuf& operator=(basic_filebuf&& rhs);
+
      
+
      
+-1- Effects: swap(rhs).
+Begins by calling this->close().
+After the move assignment *this reflects the same observable
+state it would have if it had been move constructed from rhs
+(27.9.1.2 [filebuf.cons]).
+
+
      
 
      
 
-
      [
-Batavia (2009-05):
-]
      
+
      
+Change 27.9.1.8 [ifstream.assign]/1:
+
      
 
+
      basic_ifstream& operator=(basic_ifstream&& rhs);
+
      
 
      
-The post-Summit comments have been applied to the proposed resolution.
-We now agree with the proposed resolution.
-Move to Tentatively Ready.
+-1- Effects: swap(rhs).
+Move assigns the base and members of *this with the respective
+base and members of rhs.
+
      
 
      
 
-
-
      Proposed resolution:
      
 
      
-Change 20.8.12.2.1 [unique.ptr.single.ctor]:
+Change 27.9.1.12 [ofstream.assign]/1:
 
      
 
-
      
-
      template <class U, class E> unique_ptr(unique_ptr<U, E>&& u);
+
      basic_ofstream& operator=(basic_ofstream&& rhs);
 
      
 
      
-
      
--20- Requires: If D is not a reference type,
-construction of the deleter D from an rvalue of type E
-shall be well formed and shall not throw an exception. If D is
-a reference type, then E shall be the same type as D
-(diagnostic required). unique_ptr<U, E>::pointer shall be
-implicitly convertible to pointer (diagnostic required). U shall not be
-an array type (diagnostic required). [Note: These requirements
-imply that T and U are complete types. -- end note]
-
      
+-1- Effects: swap(rhs).
+Move assigns the base and members of *this with the respective
+base and members of rhs.
 
      
 
      
 
 
      
-Change 20.8.12.2.3 [unique.ptr.single.asgn]:
+Change 27.9.1.16 [fstream.assign]/1:
 
      
 
-
      
-
      template <class U, class E> unique_ptr& operator=(unique_ptr<U, E>&& u);
+
      basic_fstream& operator=(basic_fstream&& rhs);
 
      
 
      
-
      
--6- Requires: Assignment of the deleter D from an rvalue
-D shall not throw an exception. unique_ptr<U,
-E>::pointer shall be implicitly convertible to pointer
-(diagnostic required).  U shall not be an array type (diagnostic required).
-[Note: These requirements imply that T and U
-are complete types. -- end note]
-
      
+-1- Effects: swap(rhs).
+Move assigns the base and members of *this with the respective
+base and members of rhs.
 
      
 
      
 
@@ -22245,105 +15794,70 @@ are complete types. -- end note]
 
 
 
      
-
      951. Various threading bugs #1
      
-
      Section: 20.9.2.1 [time.traits.is_fp] Status: Open
- Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-05-23
      
+
      908. Deleted assignment operators for atomic types must be volatile
      
+
      Section: 29.5 [atomics.types] Status: Open
+ Submitter: Anthony Williams Opened: 2008-09-26  Last modified: 2009-03-22
      
+
      View all other issues in [atomics.types].
      
 
      View all issues with Open status.
      
 
      Discussion:
      
 
-
      
-Related to 953.
-
      
-
-
      
-20.9.2.1 [time.traits.is_fp] says that the type Rep "is
-assumed to be ... a class emulating an integral type." What are the
-requirements for such a type?
-
      
-
      [
-2009-05-10 Howard adds:
-]
      
-
-
-
      
-IntegralLike.
-
      
-
-
      [
-Batavia (2009-05):
-]
      
+
      Addresses US 90
      
 
-
      
-
      
-As with issue 953,
-we recommend this issue be addressed in the context of providing concepts for the entire thread header.
-
      
-
      
-We look forward to proposed wording.
-
      
 
      
-Move to Open.
+The deleted copy-assignment operators for the atomic types are not
+marked as volatile in N2723, whereas the assignment operators from the
+associated non-atomic types are. e.g.
 
      
-
      
-
+
      atomic_bool& operator=(atomic_bool const&) = delete;
+atomic_bool& operator=(bool) volatile;
+
      
 
-
      Proposed resolution:
      
 
      
+This leads to ambiguity when assigning a non-atomic value to a
+non-volatile instance of an atomic type:
 
      
+
      atomic_bool b;
+b=false;
+
      
 
-
-
-
-
-
      
-
      952. Various threading bugs #2
      
-
      Section: 20.9.3.7 [time.duration.cast] Status: Tentatively NAD Editorial
- Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-05-23
      
-
      View other active issues in [time.duration.cast].
      
-
      View all other issues in [time.duration.cast].
      
-
      View all issues with Tentatively NAD Editorial status.
      
-
      Discussion:
      
 
      
-20.9.3.7 [time.duration.cast] specifies an implementation and imposes
-requirements in text (and the implementation doesn't satisfy all of the
-text requirements). Pick one.
+Both assignment operators require a standard conversions: the
+copy-assignment operator can use the implicit atomic_bool(bool)
+conversion constructor to convert false to an instance of
+atomic_bool, or b can undergo a qualification conversion in order to
+use the assignment from a plain bool.
 
      
 
 
      
-This issue is related to 946.
+This is only a problem once issue 845 is applied.
 
      
 
 
      [
-2009-05-10 Howard adds:
+Summit:
 ]
      
 
-
 
      
-
      
-The Remarks paragraph is an English re-statement of the preceeding
-Returns clause.  It was meant to be clarifying and motivating, not
-confusing.  I'm not aware with how the Remarks contradicts the Returns clause
-but I'm ok with simply removing the Remarks.
-
      
+Move to open. Assign to Lawrence. Related to US 90 comment.
 
      
 
-
      [
-Batavia (2009-05):
-]
      
 
-
      
-
      
-Pete suggests that this could be resolved
-by rephrasing the Remarks to Notes.
-
      
+
      Proposed resolution:
      
 
      
-Move to NAD Editorial.
+Add volatile qualification to the deleted copy-assignment operator of
+all the atomic types:
 
      
-
      
 
+
      atomic_bool& operator=(atomic_bool const&) volatile = delete;
+atomic_itype& operator=(atomic_itype const&) volatile = delete;
+
      
 
-
      Proposed resolution:
      
 
      
+etc.
+
      
+
      
+This will mean that the deleted copy-assignment operator will require
+two conversions in the above example, and thus be a worse match than
+the assignment from plain bool.
 
      
 
 
@@ -22351,606 +15865,512 @@ Move to NAD Editorial.
 
 
 
      
-
      953. Various threading bugs #3
      
-
      Section: 20.9.1 [time.clock.req] Status: Open
- Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-05-23
      
-
      View other active issues in [time.clock.req].
      
-
      View all other issues in [time.clock.req].
      
+
      910. Effects of MoveAssignable
      
+
      Section: 20.2.9 [concept.copymove] Status: Open
+ Submitter: Alberto Ganesh Barbati Opened: 2008-09-29  Last modified: 2009-07-18
      
 
      View all issues with Open status.
      
 
      Discussion:
      
+
      Addresses UK 150
      
 
 
      
-Related to 951.
-
      
-
-
      
-20.9.1 [time.clock.req] says that a clock's rep member is "an
-arithmetic type or a class emulating an arithmetic type." What are the
-requirements for such a type?
+The description of the effect of operator= in the MoveAssignable
+concept, given in paragraph 7 is:
 
      
 
-
      [
-2009-05-10 Howard adds:
-]
      
-
+
      result_type  T::operator=(T&&  rv);  // inherited from HasAssign<T, T&&>
+
      
 
 
      
-This wording was aimed directly at the ArithmeticLike concept.
+Postconditions: the constructed T object is equivalent to the value of
+rv before the assignment. [Note: there is no
+requirement on the value of rv after the assignment.  --end note]
 
      
+
      
+
+
      
+The sentence contains a typo (what is the "constructed T object"?)
+probably due to a cut&paste from MoveConstructible. Moreover, the
+discussion of LWG issue 675 shows that the postcondition is too generic
+and might not reflect the user expectations. An implementation of the
+move assignment that just calls swap() would always fulfill the
+postcondition as stated, but might have surprising side-effects in case
+the source rvalue refers to an object that is not going to be
+immediately destroyed. See LWG issue 900 for another example. Due to
+the sometimes intangible nature of the "user expectation", it seems
+difficult to have precise normative wording that could cover all cases
+without introducing unnecessary restrictions. However a non-normative
+clarification could be a very helpful warning sign that swapping is not
+always the correct thing to do.
+
      
 
 
      [
-Batavia (2009-05):
+2009-05-09 Alisdair adds:
 ]
      
 
+
 
      
 
      
-We recommend this issue be addressed in the context of providing concepts
-for the entire thread header.
-
      
-
      
-May resolve for now by specifying arithmetic types,
-and in future change to ArithmeticLike.
-However, Alisdair believes this is not feasible.
-
      
-
      
-Bill disagrees.
+Issue 910 is exactly the reason BSI advanced the Editorial comment UK-150.
 
      
 
      
-We look forward to proposed wording.  Move to Open.
+The post-conditions after assignment are at a minimum that the object
+referenced by rv must be safely destructible, and the transaction should not
+leak resources.  Ideally it should be possible to simply assign rv a new
+valid state after the call without invoking undefined behaviour, but any
+other use of the referenced object would depend upon additional guarantees
+made by that type.
 
      
 
      
 
-
-
      Proposed resolution:
      
-
      
-
      
-
-
-
-
-
-
      
-
      954. Various threading bugs #4
      
-
      Section: 20.9.1 [time.clock.req] Status: Open
- Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-05-30
      
-
      View other active issues in [time.clock.req].
      
-
      View all other issues in [time.clock.req].
      
-
      View all issues with Open status.
      
-
      Discussion:
      
-
      
-Table 55 -- Clock Requirements (in 20.9.1 [time.clock.req])
-
      
-
-
        
-
      1. 
-the requirements for C1::time_point require C1 and C2
-to "refer to the same epoch", but "epoch" is not defined.
-
        2. 
-
      2. 
-"Different clocks may share a time_point definition if it is
-valid to compare their time_points by comparing their
-respective durations." What does "valid" mean here? And, since
-C1::rep is "**THE** representation type of the native
-duration and time_point" (emphasis added), there
-doesn't seem to be much room for some other representation.
-
        3. 
-
      3. 
-C1::is_monotonic has type "const bool". The
-"const" should be removed.
-
        4. 
-
      4. 
-C1::period has type ratio. ratio isn't a type, 
-it's a template. What is the required type?
-
        5. 
-
      
-
 
      [
-2009-05-10 Howard adds:
+2009-05-09 Howard adds:
 ]
      
 
 
-
        
-
      1. 
-
        
-"epoch" is purposefully not defined beyond the common English
-definition.  The C standard
-also chose not to define epoch, though POSIX did.  I believe it is a strength
-of the C standard that epoch is not defined.  When it is known that two time_points
-refer to the same epoch, then a definition of the epoch is not needed to compare
-the two time_points, or subtract them.
-
        
+
        
 
        
-A time_point and a Clock implicitly refer to an (unspecified) epoch.
-The time_point represents an offset (duration) from an epoch.
+The intent of the rvalue reference work is that the moved from rv is
+a valid object.  Not one in a singular state.  If, for example, the moved from
+object is a vector, one should be able to do anything on that moved-from
+vector that you can do with any other vector.  However you would
+first have to query it to find out what its current state is.  E.g. it might have capacity,
+it might not.  It might have a non-zero size, it might not.  But regardless,
+you can push_back on to it if you want.
 
        
-
        2. 
-
      2. 
+
 
        
-The sentence:
+That being said, most standard code is now conceptized.  That is, the concepts
+list the only operations that can be done with templated types - whether or not
+the values have been moved from.
 
        
-
        
-Different clocks 
-may share a time_point
-definition if it is valid to 
-compare their time_points by 
-comparing their respective 
-durations.
-
        
 
 
        
-is redundant and could be removed.  I believe the sentence which follows the above:
+Here is user-written code which must be allowed to be legal:
 
        
+
        #include <vector>
+#include <cstdio>
 
-
        
-C1 and C2 shall refer to the same epoch.
-
        
+template <class Allocator>
+void
+inspect(std::vector<double, Allocator>&& v)
+{
+    std::vector<double, Allocator> result(move(v));
+    std::printf("moved from vector has %u size and %u capacity\n", v.size(), v.capacity());
+    std::printf("The contents of the vector are:\n");
+    typedef typename std::vector<double, Allocator>::iterator I;
+    for (I i = v.begin(), e = v.end(); i != e; ++i)
+        printf("%f\n", *i);
+}
+
+int main()
+{
+    std::vector<double> v1(100, 5.5);
+    inspect(move(v1));
+}
+
        
 
 
        
-is sufficient.  If two clocks share the same epoch, then by definition, comparing
-their time_points is valid.
+The above program does not treat the moved-from vector as singular.  It
+only treats it as a vector with an unknown value.
 
        
-
        3. 
-
      3. 
-is_monotonic is meant to never change (be const).  It is also
-desired that this value be usable in compile-time computation and branching.
-
        4. 
-
      4. 
 
        
-This should probably instead be worded:
+I believe the current proposed wording is consistent with my view on this.
 
        
-
        
-An instantiation of ratio.
 
        
-
        5. 
-
      
 
 
      [
 Batavia (2009-05):
 ]
      
 
 
      
-
      
-Re (a): It is not clear to us whether "epoch" is a term of art.
-
      
-
      
-Re (b), (c), and (d):  We agree with Howard's comments,
-and would consider adding to (c) a static constexpr requirement.
-
      
-
      
-Move to Open pending proposed wording.
-
      
+We agree that the proposed resolution
+is an improvement over the current wording.
 
      
 
 
      [
-2009-05-25 Daniel adds:
+2009-07 Frankfurt:
 ]
      
 
 
 
      
-In regards to (d) I suggest to say "a specialization of ratio" instead of
-"An instantiation of ratio". This seems to be the better matching standard
-core language term for this kind of entity.
+Need to look at again without concepts.
 
      
 
 
      [
-2009-05-25 Ganesh adds:
+2009-07 Frankfurt:
 ]
      
 
 
 
      
-
      
-Regarding (a), I found this paper on the ISO website using the term "epoch" consistently with the current wording:
-
      
-
-
      
-http://standards.iso.org/ittf/PubliclyAvailableStandards/C030811e_FILES/MAIN_C030811e/text/ISOIEC_18026E_TEMPORAL_CS.HTM
-
      
-
      
-which is part of ISO/IEC 18026 "Information technology -- Spatial Reference Model (SRM)".
-
      
+Walter will consult with Dave and Doug.
 
      
 
 
 
-
 
      Proposed resolution:
      
-
        
-
      1. 
 
        
-Change 20.9.1 [time.clock.req] p1:
+In 20.2.9 [concept.copymove], replace the postcondition in paragraph 7 with:
 
        
+
 
        
--1- A clock is a bundle consisting of a native duration, a native time_point, and a function now() to get the 
-current time_point.  The origin of the clock's time_point is referred to as the clock's epoch as defined in 
-section 6.3 of ISO/IEC 18026.
-A clock shall meet the requirements in Table 45.
+Postconditions: *this is equivalent to the value of rv before the
+assignment. [Note: there is no requirement on the value of rv after the
+assignment, but the
+effect should be unsurprising to the user even in case rv is not
+immediately destroyed. This may require that resources previously owned
+by *this are released instead of transferred to rv. -- end note]
 
        
-
        2. 
-
      2. 
-
        
-Remove the sentence from the time_point row of the table "Clock Requirements":
-
        
-
-
-
-
-
-
-
-
        Clock requirements
        
-C1::time_point
-
-chrono::time_point<C1> or chrono::time_point<C2, C1::duration>
-
-The native time_point type of the clock.
-Different clocks may share a time_point definition if it is valid to compare their time_points by comparing their respective durations.
-C1 and C2 shall refer to the same epoch.
-
        
-
        3. 
-
      
-
        
-
      1. 
-
        
-Change the row starting with C1::period of the table "Clock Requirements":
-
        
-
-
-
-
-
-
-
-
        Clock requirements
        
-C1::period
-
-a specialization of ratio
-
-The tick period of the clock in seconds.
-
        
-
-
        2. 
-
      
 
 
 
 
 
 
      
-
      955. Various threading bugs #5
      
-
      Section: 20.9.1 [time.clock.req] Status: Open
- Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-06-07
      
-
      View other active issues in [time.clock.req].
      
-
      View all other issues in [time.clock.req].
      
+
      911. I/O streams and move/swap semantic
      
+
      Section: 27.7.1 [input.streams], 27.7.2 [output.streams] Status: Open
+ Submitter: Alberto Ganesh Barbati Opened: 2008-09-29  Last modified: 2009-07-27
      
 
      View all issues with Open status.
      
 
      Discussion:
      
 
      
-20.9.1 [time.clock.req] requires that a clock type have a member
-typedef named time_point that names an instantiation of the
-template time_point, and a member named duration that
-names an instantiation of the template duration. This mixing of
-levels is confusing. The typedef names should be different from the
-template names.
+Class template basic_istream, basic_ostream and basic_iostream
+implements public move constructors, move assignment operators and swap
+method and free functions. This might induce both the user and the
+compiler to think that those types are MoveConstructible, MoveAssignable
+and Swappable. However, those class templates fail to fulfill the user
+expectations. For example:
 
      
 
-
      [
-Post Summit, Anthony provided proposed wording.
-]
      
+
      std::ostream os(std::ofstream("file.txt"));
+assert(os.rdbuf() == 0); // buffer object is not moved to os, file.txt has been closed
 
+std::vector<std::ostream> v;
+v.push_back(std::ofstream("file.txt"));
+v.reserve(100); // causes reallocation
+assert(v[0].rdbuf() == 0); // file.txt has been closed!
 
-
      [
-2009-05-04 Howard adds:
-]
      
+std::ostream&& os1 = std::ofstream("file1.txt");
+os1 = std::ofstream("file2.txt");
+os1 << "hello, world"; // still writes to file1.txt, not to file2.txt!
 
+std::ostream&& os1 = std::ofstream("file1.txt");
+std::ostream&& os2 = std::ofstream("file2.txt");
+std::swap(os1, os2);
+os1 << "hello, world"; // writes to file1.txt, not to file2.txt!
+
      
 
-
      
 
      
-The reason that the typedef names were given the same name as the class templates
-was so that clients would not have to stop and think about whether they were
-using the clock's native time_point / duration or the class
-template directly.  In this case, one person's confusion is another person's
-encapsulation.  The detail that sometimes one is referring to the clock's
-native types, and sometimes one is referring to an independent type is
-purposefully "hidden" because it is supposed to be an unimportant
-detail.  It can be confusing to have to remember when to type duration
-and when to type duration_type, and there is no need to require the
-client to remember something like that.
+This is because the move constructor, the move assignment operator and
+swap are all implemented through calls to std::basic_ios member
+functions move() and swap() that do not move nor swap the controlled
+stream buffers. That can't happen because the stream buffers may have
+different types.
 
      
 
 
      
-For example, here is code that I once wrote in testing out the usability of
-this facility:
+Notice that for basic_streambuf, the member function swap() is
+protected. I believe that is correct and all of basic_istream,
+basic_ostream, basic_iostream should do the same as the move ctor, move
+assignment operator and swap member function are needed by the derived
+fstreams and stringstreams template. The free swap functions for
+basic_(i|o|io)stream templates should be removed for the same reason.
 
      
 
-
      template <class Clock, class Duration>
-void do_until(const std::chrono::time_point<Clock, Duration>& t)
-{
-    typename Clock::time_point now = Clock::now();
-    if (t > now)
-    {
-        typedef typename std::common_type
-        <
-            Duration,
-            typename std::chrono::system_clock::duration
-        >::type CD;
-        typedef std::chrono::duration<double, std::nano> ID;
-
-        CD d = t - now;
-        ID us = duration_cast<ID>(d);
-        if (us < d)
-            ++us;
-        ...
-    }
-}
-
      
+
      [
+Batavia (2009-05):
+]
      
 
+
      
 
      
-I see no rationale to require the client to append _type to some
-of those declarations.  It seems overly burdensome on the author of do_until:
+We note that the rvalue swap functions have already been removed.
+
      
+
      
+Bill is unsure about making the affected functions protected;
+he believes they may need to be public.
+
      
+
      
+We are also unsure about removing the lvalue swap functions as proposed.
+
      
+
      
+Move to Open.
 
      
+
      
 
-
      template <class Clock, class Duration>
-void do_until(const std::chrono::time_point<Clock, Duration>& t)
-{
-    typename Clock::time_point_type now = Clock::now();
-    if (t > now)
-    {
-        typedef typename std::common_type
-        <
-            Duration,
-            typename std::chrono::system_clock::duration_type
-        >::type CD;
-        typedef std::chrono::duration<double, std::nano> ID;
+
      [
+2009-07 Frankfurt:
+]
      
 
-        CD d = t - now;
-        ID us = duration_cast<ID>(d);
-        if (us < d)
-            ++us;
-        ...
-    }
-}
-
      
 
+
      
 
      
-Additionally I'm fairly certain that this suggestion hasn't been implemented.
-If it had, it would have been discovered that it is incomplete.  time_point
-also has a nested type (purposefully) named duration.
+It's not clear that the use case is compelling.
 
      
-
      
-That is, the current proposed wording would put the WP into an inconsistent state.
-
      
 
      
-In contrast,
-the current WP has been implemented and I've received very favorable feedback
-from people using this interface in real-world code.
+Howard: This needs to be implemented and tested.
 
      
-
 
      
 
 
      [
-Batavia (2009-05):
+2009-07-26 Howard adds:
 ]
      
 
+
 
      
 
      
-Bill agrees that distinct names should be used for distinct kinds of entities.
+I started out thinking I would recommend NAD for this one.  I've turned around
+to agree with the proposed resolution (which I've updated to the current draft).
+I did not fully understand Ganesh's rationale, and attempt to describe my
+improved understanding below.
 
      
+
 
      
-Walter would prefer not to suffix type names,
-especially for such well-understood terms as "duration".
+The move constructor, move assignment operator, and swap function are different
+for basic_istream, basic_ostream and basic_iostream
+than other classes.  A timely conversation with Daniel reminded me of this long
+forgotten fact.  These members are sufficiently different that they would be
+extremely confusing to use in general, but they are very much needed for derived
+clients.
+
      
+
+
        
+
      • 
+The move constructor moves everything but the rdbuf pointer.
+
        • 
+
      • 
+The move assignment operator moves everything but the rdbuf pointer.
+
        • 
+
      • 
+The swap function swaps everything but the rdbuf pointer.
+
        • 
+
      
+
+
      
+The reason for this behavior is that for the std-derived classes (stringstreams,
+filestreams), the rdbuf pointer points back into the class itself
+(self referencing).  It can't be swapped or moved.  But this fact isn't born out
+at the stream level.  Rather it is born out at the fstream/sstream
+level.  And the lower levels just need to deal with that fact by not messing around
+with the rdbuf pointer which is stored down at the lower levels.
 
      
+
 
      
-Howard reminds us that the proposed resolution is incomplete, per his comment
-in the issue.
+In a nutshell, it is very confusing for all of those who are not so intimately
+related with streams that they've implemented them.  And it is even fairly
+confusing for some of those who have (including myself).  I do not think it is
+safe to swap or move istreams or ostreams because this will
+(by necessary design) separate stream state from streambuffer state.  Derived
+classes (such as fstream and stringstream must be used to
+keep the stream state and stream buffer consistently packaged as one unit during
+a move or swap.
 
      
+
 
      
-Move to Open.
+I've implemented this proposal and am living with it day to day.
 
      
+
 
      
 
-
      [
-2009-06-07 Howard adds:
-]
      
 
 
-
      
+
      Proposed resolution:
      
 
      
-Not meaning to be argumentative, but we have a decade of positive experience
-with the precedent of using the same name for the nested type as an external
-class representing an identical concept.
+27.7.1.1 [istream]: make the following member functions protected:
 
      
 
-
      template<class Category, class T, class Distance = ptrdiff_t,
-         class Pointer = T*, class Reference = T&>
-struct iterator
-{
-    ...
-};
+
      basic_istream(basic_istream&&  rhs);
+basic_istream&  operator=(basic_istream&&  rhs);
+void  swap(basic_istream&  rhs);
+
      
 
-template <BidirectionalIterator Iter>
-class reverse_iterator
-{
-    ...
-};
+
      
+Ditto: remove the swap free function signature
+
      
 
-template <ValueType T, Allocator Alloc = allocator<T> >
-    requires NothrowDestructible<T>
-class list
-{
-public:
-    typedef implementation-defined     iterator;
-    ...
-    typedef reverse_iterator<iterator> reverse_iterator;
-    ...
-};
+
      // swap: 
+template <class charT, class traits> 
+  void swap(basic_istream<charT, traits>& x, basic_istream<charT, traits>& y);
 
      
 
 
      
-I am aware of zero complaints regarding the use of iterator
-and reverse_iterator as nested types of the containers despite these
-names also having related meaning at namespace std scope.
+27.7.1.1.2 [istream.assign]: remove paragraph 4
 
      
 
+
      template <class charT, class traits> 
+  void swap(basic_istream<charT, traits>& x, basic_istream<charT, traits>& y);
+
      
+
      
+Effects: x.swap(y).
+
      
+
      
+
 
      
-Would we really be doing programmers a favor by renaming these nested types?
+27.7.1.5 [iostreamclass]: make the following member function protected:
 
      
 
-
      template <ValueType T, Allocator Alloc = allocator<T> >
-    requires NothrowDestructible<T>
-class list
-{
-public:
-    typedef implementation-defined     iterator_type;
-    ...
-    typedef reverse_iterator<iterator> reverse_iterator_type;
-    ...
-};
+
      basic_iostream(basic_iostream&&  rhs);
+basic_iostream&  operator=(basic_iostream&&  rhs);
+void  swap(basic_iostream&  rhs);
 
      
 
 
      
-I submit that such design contributes to needless verbosity which ends up
-reducing readability.
+Ditto: remove the swap free function signature
+
      
+
+
      template <class charT, class traits> 
+  void swap(basic_iostream<charT, traits>& x, basic_iostream<charT, traits>& y);
+
      
+
+
      
+27.7.1.5.3 [iostream.assign]: remove paragraph 3
 
      
+
+
      template <class charT, class traits> 
+  void swap(basic_iostream<charT, traits>& x, basic_iostream<charT, traits>& y);
+
      
+
      
+Effects: x.swap(y).
+
      
 
      
 
+
      
+27.7.2.1 [ostream]: make the following member function protected:
+
      
 
+
      basic_ostream(basic_ostream&&  rhs);
+basic_ostream&  operator=(basic_ostream&&  rhs);
+void  swap(basic_ostream&  rhs);
+
      
 
-
      Proposed resolution:
      
 
      
-Change 20.9 [time]:
+Ditto: remove the swap free function signature
 
      
 
-
      ...
-template <class Clock, class Duration = typename Clock::duration_type> class time_point;
-...
+
      // swap: 
+template <class charT, class traits> 
+  void swap(basic_ostream<charT, traits>& x, basic_ostream<charT, traits>& y);
 
      
 
 
      
-Change 20.9.1 [time.clock.req]:
+27.7.2.3 [ostream.assign]: remove paragraph 4 
 
      
 
+
      template <class charT, class traits> 
+  void swap(basic_ostream<charT, traits>& x, basic_ostream<charT, traits>& y);
+
      
 
      
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
      Table 45 -- Clock requirements
      ExpressionReturn typeOperational semantics
      .........
      C1::duration_typechrono::duration<C1::rep, C1::period>The native duration type of the clock.
      C1::time_point_typechrono::time_point<C1> or chrono::time_point<C2, C1::duration_type<The native time_point type of the clock.   Different clocks may  share a time_point_type
-definition if it is valid to 
-compare their time_point_types by 
-comparing their respective 
-duration_types. C1 and C2 shall 
-refer to the same epoch.
      .........
      C1::now()C1::time_point_typeReturns a time_point_type object 
-representing the current point 
-in time.
-
      
+Effects: x.swap(y).
+
      
 
      
 
+
+
+
+
+
+
      
+
      915. minmax with initializer_list should return
+pair of T, not pair of const T&
      
+
      Section: 25.5.7 [alg.min.max] Status: Open
+ Submitter: Daniel Krügler Opened: 2008-10-04  Last modified: 2009-07-14
      
+
      View all other issues in [alg.min.max].
      
+
      View all issues with Open status.
      
+
      Discussion:
      
 
      
-Change 20.9.5.1 [time.clock.system]:
+It seems that the proposed changes for
+N2772
+were not clear enough in
+this point:
 
      
 
 
      
-
      
--1- Objects of class system_clock represent wall clock time from the system-wide realtime clock.
-
      
+25.5.7 [alg.min.max], before p.23 + p.24 + before p. 27 + p. 28 say that the return
+type of the minmax overloads with an initializer_list is
+pair<const T&, const T&>,
+which is inconsistent with the decision for the other min/max overloads which take
+a initializer_list as argument and return a T, not a const T&.
+Doing otherwise for minmax would easily lead to unexpected life-time
+problems by using minmax instead of min and max separately.
+
      
 
-
      class system_clock { 
-public: 
-  typedef see below rep; 
-  typedef ratio<unspecified, unspecified> period; 
-  typedef chrono::duration<rep, period> duration_type; 
-  typedef chrono::time_point<system_clock> time_point_type; 
-  static const bool is_monotonic = unspecified ; 
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
      [
+2009-07 Frankfurt
+]
      
+
+
+
      
+Moved from Tentatively Ready to Open only because the wording needs to be
+tweaked for concepts removal.
+
      
 
-  static time_point_type now(); 
 
-  // Map to C API 
-  static time_t to_time_t (const time_point_type& t); 
-  static time_point_type from_time_t(time_t t); 
-};
-
      
 
+
      Proposed resolution:
      
+
        
+
      1. 
 
        
--2- system_clock::duration_type::min() < system_clock::duration_type::zero() shall be true.
+In 25 [algorithms]/2, header <algorithm> synopsis change as indicated:
 
        
 
-
        time_t to_time_t(const time_point_type& t);
-
        
+
        template<classLessThanComparable T>
+requires CopyConstructible<T>
+pair<const T&, const T&>
+minmax(initializer_list<T> t);
 
+template<class T, classStrictWeakOrder<auto, T> Compare>
+requires CopyConstructible<T>
+pair<const T&, const T&>
+minmax(initializer_list<T> t, Compare comp);
+
        
+
        2. 
+
      2. 
+
        
+In 25.5.7 [alg.min.max] change as indicated (Begin: Just before p.20):
+
        
+
        template<classLessThanComparable T>
+  requires CopyConstructible<T>
+  pair<const T&, const T&>
+  minmax(initializer_list<T> t);
+
        
 
        
--3- Returns: A time_t object that represents the same
-point in time as t when both values are truncated to the
-coarser of the precisions of time_t and time_point_type.
+
        
+-20- Requires: T is LessThanComparable and
+CopyConstructible.
+
        
+
        
+-21- Returns: pair<const T&, const
+T&>(x, y) where x is the
+smallest value and y the largest value in the initializer_list.
+
        
 
        
 
-
        time_point_type from_time_t(time_t t);
+
        [..]
        
+
        template<class T, classStrictWeakOrder<auto, T> Compare>
+  requires CopyConstructible<T>
+  pair<const T&, const T&>
+  minmax(initializer_list<T> t, Compare comp);
 
        
 
 
        
--4- Returns: A time_point_type object that represents the same point
-in time as t when both values are truncated to the coarser of the
-precisions of time_t and time_point_type.
-
        
-
        
-
 
        
-Change 20.9.5.2 [time.clock.monotonic]:
+-24- Requires: type T is LessThanComparable and CopyConstructible.
 
        
-
-
        class monotonic_clock { 
-public: 
-  typedef unspecified                                rep; 
-  typedef ratio<unspecified , unspecified>           period; 
-  typedef chrono::duration<rep, period>              duration_type; 
-  typedef chrono::time_point<unspecified , duration_type> time_point_type; 
-  static const bool is_monotonic =                   true; 
-
-  static time_point_type now();
-};
-
        
-
 
        
-Change 20.9.5.3 [time.clock.hires]:
+-25- Returns: pair<const T&, const
+T&>(x, y) where x is the
+smallest value and y largest value in the initializer_list.
 
        
-
-
        class high_resolution_clock { 
-public: 
-  typedef unspecified                                rep; 
-  typedef ratio<unspecified , unspecified>           period; 
-  typedef chrono::duration<rep, period>              duration_type; 
-  typedef chrono::time_point<unspecified , duration_type> time_point_type; 
-  static const bool is_monotonic =                   true; 
-
-  static time_point_type now();
-};
-
        
+
      
+
      
+
+
    @@ -22958,68 +16378,111 @@ public:
    -

    956. Various threading bugs #6

    -

    Section: 20.9.1 [time.clock.req] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-05-23

    -

    View other active issues in [time.clock.req].

    -

    View all other issues in [time.clock.req].

    +

    916. Redundant move-assignment operator of pair should be removed

    +

    Section: 20.3.3 [pairs] Status: Open + Submitter: Daniel Krügler Opened: 2008-10-04 Last modified: 2009-07-18

    +

    View other active issues in [pairs].

    +

    View all other issues in [pairs].

    View all issues with Open status.

    Discussion:

    +

    see also 917.

    +

    -20.9.1 [time.clock.req] uses the word "native" in several places, -but doesn't define it. What is a "native duration"? +The current WP provides the following assignment operators for pair +in 20.3.3 [pairs]/1: +

    + +
      +
    1. +
      template<class U , class V>
+requires HasAssign<T1, const U&> && HasAssign<T2, const V&>
+pair& operator=(const pair<U , V>& p);
+
      +
      2. +
    2. +
      requires MoveAssignable<T1> && MoveAssignable<T2> pair& operator=(pair&& p );
+
      +
      3. +
    3. +
      template<class U , class V>
+requires HasAssign<T1, RvalueOf<U>::type> && HasAssign<T2, RvalueOf<V>::type>
+pair& operator=(pair<U , V>&& p);
+
      +
      4. +
    + +

    +It seems that the functionality of (2) is completely covered by (3), therefore +(2) should be removed.

    [ -2009-05-10 Howard adds: +Batavia (2009-05): ]

    -
    -The standard uses "native" in several places without defining it (e.g. -2.14.3 [lex.ccon]). It is meant to mean "that which is defined -by the facility", or something along those lines. In this case it refers -to the nested time_point and duration types of the clock. -Better wording is welcome. +

    +Bill believes the extra assignment operators are necessary for resolving +ambiguities, but that does not mean it needs to be part of the specification. +

    +

    +Move to Open. +We recommend this be looked at in the context of the ongoing work +related to the pair templates. +

    [ -Batavia (2009-05): +2009-07 Frankfurt: ]

    +
    -Move to Open pending proposed wording from Pete. +Leave this open pending the removal of concepts from the WD.
    +

    Proposed resolution:

    +
      +

    1. +In 20.3.3 [pairs] p. 1, class pair and just before p. 13 remove the declaration:

      +
      requires MoveAssignable<T1> && MoveAssignable<T2> pair& operator=(pair&& p );
+
      +
      2. + +
    2. +Remove p.13+p.14 +
      3. + +
    +
    -

    957. Various threading bugs #7

    -

    Section: 20.9.5.1 [time.clock.system] Status: Review - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-05-23

    -

    View other active issues in [time.clock.system].

    -

    View all other issues in [time.clock.system].

    -

    View all issues with Review status.

    +

    917. Redundant move-assignment operator of tuple should be removed

    +

    Section: 20.5.2.1 [tuple.cnstr] Status: Open + Submitter: Daniel Krügler Opened: 2008-10-04 Last modified: 2009-07-18

    +

    View other active issues in [tuple.cnstr].

    +

    View all other issues in [tuple.cnstr].

    +

    View all issues with Open status.

    Discussion:

    +

    see also 916.

    -20.9.5.1 [time.clock.system]: to_time_t is overspecified. It -requires truncation, but should allow rounding. For example, suppose a -system has a clock that gives times in milliseconds, but time() rounds -those times to the nearest second. Then system_clock can't use any -resolution finer than one second, because if it did, truncating times -between half a second and a full second would produce the wrong time_t -value. +N2770 (and thus now the WP) removed the +non-template move-assignment operator from tuple's class definition, +but the latter individual member description does still provide this +operator. Is this (a) an oversight and can it (b) be solved as part of an +editorial process?

    [ -Post Summit Anthony Williams provided proposed wording. +Post Summit Daniel provided wording. ]

    @@ -23028,595 +16491,670 @@ Batavia (2009-05): ]

    -Move to Review pending input from Howard. and other stakeholders. +

    +We believe that the proposed resolution's part 1 is editorial. +

    +

    +Regarding part 2, we either remove the specification as proposed, +or else add back the declaration to which the specification refers. +Alisdair and Bill prefer the latter. +It is not immediately obvious whether the function is intended to be present. +

    +

    +We recommend that the Project Editor restore the missing declaration +and that we keep part 2 of the issue alive. +

    +

    +Move to Open. +

    [ -2009-05-23 Howard adds: +2009-07 Frankfurt: ]

    -I am in favor of the wording provided by Anthony. +Leave this open pending the removal of concepts from the WD.
    +

    Proposed resolution:

    +
      +

    1. -In 20.9.5.1 [time.clock.system] replace paragraphs 3 and 4 with: +In 20.5.2 [tuple.tuple], class tuple just before member swap please +change as indicated:

      +

      [ +This fixes an editorial loss between N2798 to N2800 +]

      -
      -
      time_t to_time_t(const time_point& t);
-
      -
      --3- Returns: A time_t object that represents the same -point in time as t when both values are truncated -restricted to the coarser of the precisions of -time_t and time_point. It is implementation -defined whether values are rounded or truncated to the required -precision. -
      +
      template <class... UTypes>
+requires HasAssign<Types, const UTypes&>...
+tuple& operator=(const pair<UTypes...>&);
 
-
      time_point from_time_t(time_t t);
+template <class... UTypes>
+requires HasAssign<Types, RvalueOf<UTypes>::type>...
+tuple& operator=(pair<UTypes...>&&);
+
      +
      2. +
    2. +

      +In 20.5.2.1 [tuple.cnstr], starting just before p. 11 please remove +as indicated: +

      + +
      requires MoveAssignable<Types>... tuple& operator=(tuple&& u);
      --4- Returns: A time_point object that represents the -same point in time as t when both values are truncated -restricted to the -coarser of the precisions of time_t and time_point. -It is implementation defined whether values are -rounded or truncated to the required precision. +

      +-11- Effects: Move-assigns each element of u to the corresponding +element of *this. +

      +

      +-12- Returns: *this. +

      +
      3. +
    -

    958. Various threading bugs #8

    -

    Section: 30.5.1 [thread.condition.condvar] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-22

    -

    View other active issues in [thread.condition.condvar].

    -

    View all other issues in [thread.condition.condvar].

    +

    919. (forward_)list specialized remove algorithms are over constrained

    +

    Section: 23.3.3.5 [forwardlist.ops], 23.3.4.4 [list.ops] Status: Open + Submitter: Daniel Krügler Opened: 2008-10-06 Last modified: 2009-07-21

    +

    View other active issues in [forwardlist.ops].

    +

    View all other issues in [forwardlist.ops].

    View all issues with Open status.

    Discussion:

    -30.5.1 [thread.condition.condvar]: the specification for wait_for -with no predicate has an effects clause that says it calls wait_until, -and a returns clause that sets out in words how to determine the return -value. Is this description of the return value subtly different from the -description of the value returned by wait_until? Or should the effects -clause and the returns clause be merged? +The signatures of forwardlist::remove and list::remove +defined in 23.3.3.5 [forwardlist.ops] before 11 + 23.3.4.4 [list.ops] before 15: +

    + +
    requires EqualityComparable<T> void remove(const T& value);
+
    + +

    +are asymmetric to their predicate variants (which only require +Predicate, not EquivalenceRelation) and with the free algorithm +remove (which only require HasEqualTo). Also, nothing in the +pre-concept WP +N2723 +implies that EqualityComparable should +be the intended requirement. +

    + +

    [ +Batavia (2009-05): +]

    + +
    +

    +We agree with the proposed resolution, +but would like additional input from concepts experts.

    +

    +Move to Review. +

    +

    [ -Summit: +2009-07-21 Alisdair adds: ]

    -Move to open. Associate with LWG 859 and any other monotonic-clock -related issues. +Current rationale and wording for this issue is built around concepts. I +suggest the issue reverts to Open status.  I believe there is enough of +an issue to review after concepts are removed from the WP to re-examine +the issue in Santa Cruz, rather than resolve as NAD Concepts.

    Proposed resolution:

    +
      +

    1. +Replace in 23.3.3.5 [forwardlist.ops] before 11 and in 23.3.4.4 [list.ops] before 15

      +
      requires EqualityComparable<T> HasEqualTo<T, T> void remove(const T& value);
+
      +
      2. +
    + +
    -

    959. Various threading bugs #9

    -

    Section: 30.5.1 [thread.condition.condvar] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-22

    -

    View other active issues in [thread.condition.condvar].

    -

    View all other issues in [thread.condition.condvar].

    +

    920. Ref-qualification support in the library

    +

    Section: 20.7.15 [func.memfn] Status: Open + Submitter: Bronek Kozicki Opened: 2008-10-06 Last modified: 2009-05-23

    View all issues with Open status.

    Discussion:

    -30.5.1 [thread.condition.condvar]: condition_variable::wait_for -is required to compute the absolute time by adding the duration value to -chrono::monotonic_clock::now(), but monotonic_clock is not required to -exist. +Daniel Krügler wrote:

    -

    [ -Summit: -]

    - -
    -Move to open. Associate with LWG 859 and any other monotonic-clock -related issues. -
    - - -

    Proposed resolution:

    +Shouldn't above list be completed for &- and &&-qualified +member functions This would cause to add:

    +
    template<Returnable R, class T, CopyConstructible... Args>
+unspecified mem_fn(R (T::* pm)(Args...) &);
+template<Returnable R, class T, CopyConstructible... Args>
+unspecified mem_fn(R (T::* pm)(Args...) const &);
+template<Returnable R, class T, CopyConstructible... Args>
+unspecified mem_fn(R (T::* pm)(Args...) volatile &);
+template<Returnable R, class T, CopyConstructible... Args>
+unspecified mem_fn(R (T::* pm)(Args...) const volatile &);
+template<Returnable R, class T, CopyConstructible... Args>
+unspecified mem_fn(R (T::* pm)(Args...) &&);
+template<Returnable R, class T, CopyConstructible... Args>
+unspecified mem_fn(R (T::* pm)(Args...) const &&);
+template<Returnable R, class T, CopyConstructible... Args>
+unspecified mem_fn(R (T::* pm)(Args...) volatile &&);
+template<Returnable R, class T, CopyConstructible... Args>
+unspecified mem_fn(R (T::* pm)(Args...) const volatile &&);
+
    + - - - -
    -

    960. Various threading bugs #10

    -

    Section: 30.4.1 [thread.mutex.requirements] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-27

    -

    View other active issues in [thread.mutex.requirements].

    -

    View all other issues in [thread.mutex.requirements].

    -

    View all issues with Open status.

    -

    Discussion:

    -30.4.1 [thread.mutex.requirements]: paragraph 4 is entitled -"Error conditions", but according to 17.5.1.4 [structure.specifications], "Error -conditions:" specifies "the error conditions for error codes reported by -the function." It's not clear what this should mean when there is no -function in sight. +yes, absolutely. Thanks for spotting this. Without this change mem_fn +cannot be initialized from pointer to ref-qualified member function. I +believe semantics of such function pointer is well defined.

    [ -Summit: +Post Summit Daniel provided wording. ]

    -
    -Move to open. -
    -

    [ -Beman provided proposed wording. +Batavia (2009-05): ]

    - - -

    Proposed resolution:

    +

    -Change 30.4.1 [thread.mutex.requirements] Mutex requirements, -paragraph 4 as indicated: +We need to think about whether we really want to go down the proposed path +of combinatorial explosion. +Perhaps a Note would suffice.

    - -

    --4- Error conditions: -The error conditions for error codes, if any, reported by member -functions of type Mutex shall be: +We would really like to have an implementation before proceeding.

    -
      -
    • -not_enough_memory -- if there is not enough memory to construct -the mutex object. -
      • -
    • -resource_unavailable_try_again -- if any native handle type -manipulated is not available. -
      • -
    • -operation_not_permitted -- if the thread does not have the -necessary permission to change the state of the mutex object. -
      • +

      +Move to Open, and recommend this be deferred until after the next +Committee Draft has been issued. +

      +
    + + +

    Proposed resolution:

    +
    1. -device_or_resource_busy -- if any native handle type -manipulated is already locked. +

      +In 20.7 [function.objects]/2, header <functional> synopsis, just after +the section "// 20.6.15, member function adaptors::" add the following +declarations to the existing list: +

      +
      template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) &);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) const &);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) volatile &);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) const volatile &);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) &&);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) const &&);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) volatile &&);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) const volatile &&);
+
    2. -invalid_argument -- if any native handle type manipulated as -part of mutex construction is incorrect. +

      +In 20.7.15 [func.memfn] add the following declarations to the existing +list: +

      +
      template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) &);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) const &);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) volatile &);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) const volatile &);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) &&);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) const &&);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) volatile &&);
+template<Returnable R, class T, CopyConstructible... Args>
+  unspecified mem_fn(R (T::* pm)(Args...) const volatile &&);
+
      3. - -
    + +

    +The following text, most notably p.2 and p.3 which discuss influence +of the cv-qualification on the definition of the base class's first template +parameter remains unchanged. +

    -

    961. Various threading bugs #11

    -

    Section: 30.4.1 [thread.mutex.requirements] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-22

    -

    View other active issues in [thread.mutex.requirements].

    -

    View all other issues in [thread.mutex.requirements].

    -

    View all issues with Open status.

    +

    921. Rational Arithmetic should use template aliases

    +

    Section: 20.4.1 [ratio.ratio] Status: Review + Submitter: Pablo Halpern Opened: 2008-10-07 Last modified: 2009-07-21

    +

    View other active issues in [ratio.ratio].

    +

    View all other issues in [ratio.ratio].

    +

    View all issues with Review status.

    Discussion:

    -30.4.1 [thread.mutex.requirements] describes required member -functions of mutex types, and requires that they throw exceptions under -certain circumstances. This is overspecified. User-defined types can -abort on such errors without affecting the operation of templates -supplied by standard-library. +The compile-time functions that operate on ratio<N,D> require the +cumbersome and error-prone "evaluation" of a type member using a +meta-programming style that predates the invention of template aliases. +Thus, multiplying three ratios a, b, and c requires the expression:

    -

    [ -Summit: -]

    - -
    -Move to open. Related to conceptualization and should probably be -tackled as part of that. -
    - +
    ratio_multiply<a, ratio_multiply<b, c>::type>::type
+
    -

    Proposed resolution:

    +The simpler expression:

    +
    ratio_multiply<a, ratio_multiply<b, c>>
+
    - - - -
    -

    962. Various threading bugs #12

    -

    Section: 30.4.3.2.2 [thread.lock.unique.locking] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-22

    -

    View all issues with Open status.

    -

    Discussion:

    -30.4.3.2.2 [thread.lock.unique.locking]: unique_lock::lock is -required to throw an object of type std::system_error "when the -postcondition cannot be achieved." The postcondition is owns == true, -and this is trivial to achieve. Presumably, the requirement is intended -to mean something more than that. +Could be used by if template aliases were employed in the definitions.

    [ -Summit: -]

    - -
    -Move to open. -
    - -

    [ -Beman has volunteered to provide proposed wording. +Post Summit: ]

    - - -

    Proposed resolution:

    +

    -

    - - - - - -
    -

    963. Various threading bugs #13

    -

    Section: 30.3.1.5 [thread.thread.member] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-22

    -

    View other active issues in [thread.thread.member].

    -

    View all other issues in [thread.thread.member].

    -

    View all issues with Open status.

    -

    Discussion:

    +Jens: not a complete proposed resolution: "would need to make similar change" +

    -30.3.1.5 [thread.thread.member]: thread::detach is required to -throw an exception if the thread is "not a detachable thread". -"Detachable" is never defined. +Consensus: We agree with the direction of the issue. +

    +

    +Recommend Open.

    +

    [ -Howard adds: +2009-05-11 Daniel adds: ]

    -Due to a mistake on my part, 3 proposed resolutions appeared at approximately -the same time. They are all three noted below in the discussion. +

    +Personally I'm not in favor for the addition of: +

    +
    typedef ratio type;
+
    +

    +For a reader of the +standard it's usage or purpose is unclear. I haven't seen similar examples +of attempts to satisfy non-feature complete compilers. +

    [ -Summit, proposed resolution: +2009-05-11 Pablo adds: ]

    -In 30.3.1.5 [thread.thread.member] change: +The addition of type to the ratio template allows the previous style +(i.e., in the prototype implementations) to remain valid and permits the +use of transitional library implementations for C++03 compilers. I do +not feel strongly about its inclusion, however, and leave it up to the +reviewers to decide.

    - -
    void detach();
-
    -
    -

    ...

    -

    -14- Error conditions:

    -
      -
    • no_such_process -- if the thread is not a valid thread.
      • -
    • invalid_argument -- if the thread is not a detachable joinable thread.
      • -
    -
    +

    [ +Batavia (2009-05): +]

    +
    +Bill asks for additional discussion in the issue +that spells out more details of the implementation. +Howard points us to issue 948 +which has at least most of the requested details. +Tom is strongly in favor of overflow-checking at compile time. +Pete points out that there is no change of functionality implied. +We agree with the proposed resolution, +but recommend moving the issue to Review +to allow time to improve the discussion if needed.

    [ -Post Summit, Jonathan Wakely adds: +2009-07-21 Alisdair adds: ]

    +See 1121 for a potentially incompatible proposal. +
    + + +

    Proposed resolution:

    + + +
      +

    1. -A thread is detachable if it is joinable. As we've defined joinable, -we can just use that. +In 20.4 [ratio]/3 change as indicated:

      + +
      // ratio arithmetic
+template <class R1, class R2> structusing ratio_add = see below;
+template <class R1, class R2> structusing ratio_subtract = see below;
+template <class R1, class R2> structusing ratio_multiply = see below;
+template <class R1, class R2> structusing ratio_divide = see below;
+
      +
      2. +

    2. -This corresponds to the pthreads specification, where pthread_detach -fails if the thread is not joinable: +In 20.4.1 [ratio.ratio], change as indicated:

      -
      -EINVAL: The implementation has detected that the value specified by -thread does not refer to a joinable thread. -
      +
      namespace std {
+  template <intmax_t N, intmax_t D = 1>
+  class ratio {
+  public:
+    typedef ratio type;
+    static const intmax_t num;
+    static const intmax_t den;
+  };
+}
+
      +
      3. +

    3. -Jonathan recommends this proposed wording: +In 20.4.2 [ratio.arithmetic] change as indicated:

      + +
      template <class R1, class R2> structusing ratio_add = see below{
+  typedef see below type;
+};
+
      +

      -In 30.3.1.5 [thread.thread.member] change: +1 The nested typedef type ratio_add<R1, R2> +shall be a synonym for ratio<T1, T2> +where T1 has the value R1::num * R2::den + R2::num * R1::den and T2 +has the value R1::den * R2::den.

      - -
      void detach();
+
      +
      +
      template <class R1, class R2> structusing ratio_subtract = see below{
+  typedef see below type;
+};
      -

      ...

      -

      -14- Error conditions:

      -
        -
      • ...
        • -
      • invalid_argument -- not a detachable joinable thread.
        • -
      +

      +2 The nested typedef type ratio_subtract<R1, R2> +shall be a synonym for ratio<T1, T2> +where T1 has the value R1::num * R2::den - R2::num * R1::den and T2 +has the value R1::den * R2::den. +

      -
      +
      template <class R1, class R2> structusing ratio_multiply = see below{
+  typedef see below type;
+};
+
      +
      +

      +3 The nested typedef type ratio_multiply<R1, R2> +shall be a synonym for ratio<T1, T2> +where T1 has the value R1::num * R2::num and T2 has the value R1::den * R2::den. +

      - -

      [ -Post Summit, Anthony Williams adds: -]

      - - +
      template <class R1, class R2> structusing ratio_divide = see below{
+  typedef see below type;
+};
+

      -This is covered by the precondition that joinable() be true. +4 The nested typedef type ratio_divide<R1, R2> +shall be a synonym for ratio<T1, T2> +where T1 has the value R1::num * R2::den and T2 has the value R1::den * R2::num.

      +
      +
      +
      4. +

    4. -Anthony recommends this proposed wording: +In 20.9.3.1 [time.duration.cons]/4 change as indicated:

      -

      -In 30.3.1.5 [thread.thread.member] change: +Requires: treat_as_floating_point<rep>::value shall be true or +ratio_divide<Period2, period>::type::den shall be 1.[..]

      - -
      void detach();
-
      -
      -

      ...

      -

      -14- Error conditions:

      -
        -
      • ...
        • -
      • invalid_argument -- not a detachable thread.
        • -
      -
      - -
      -
      - +
      5. +
    5. +

      +In 20.9.3.7 [time.duration.cast]/2 change as indicated: +

      +
      +

      +Returns: Let CF be ratio_divide<Period, typename +ToDuration::period>::type, and [..] +

      - - - -

      Proposed resolution:

      +
      6. +
    -

    964. Various threading bugs #14

    -

    Section: 30.5.2 [thread.condition.condvarany] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-22

    +

    923. atomics with floating-point

    +

    Section: 29 [atomics] Status: Open + Submitter: Herb Sutter Opened: 2008-10-17 Last modified: 2009-05-01

    +

    View other active issues in [atomics].

    +

    View all other issues in [atomics].

    View all issues with Open status.

    Discussion:

    -The requirements for the constructor for condition_variable has several -error conditions, but the requirements for the constructor for -condition_variable_any has none. Is this difference intentional? +Right now, C++0x doesn't have atomic<float>. We're thinking of adding +the words to support it for TR2 (note: that would be slightly +post-C++0x). If we need it, we could probably add the words. +

    +

    +Proposed resolutions: Using atomic<FP>::compare_exchange (weak or +strong) should be either:

    -

    [ -Summit: -]

    - - -
    -Move to open, pass to Howard. If this is intentional, a note may be -helpful. If the error conditions are to be copied from -condition_variable, this depends on LWG 965. -
    - -

    [ -Post Summit Howard adds: -]

    - - -
    -The original intention -(N2447) -was to let the OS return whatever errors it was going to return, and for -those to be translated into exceptions, for both -condition_variable and condition_variable_any. I have not -received any complaints about specific error conditions from vendors on -non-POSIX platforms, but such complaints would not surprise me if they surfaced. -
    - - -

    Proposed resolution:

    - - - - +
      +
    1. +ill-formed, or +
      2. +
    2. +well-defined. +
      3. +
    -
    -

    965. Various threading bugs #15

    -

    Section: 30.5.1 [thread.condition.condvar] Status: Tentatively Ready - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-05-23

    -

    View other active issues in [thread.condition.condvar].

    -

    View all other issues in [thread.condition.condvar].

    -

    View all issues with Tentatively Ready status.

    -

    Discussion:

    -30.5.1 [thread.condition.condvar]: the constructor for -condition_variable throws an exception with error code -device_or_resource_busy "if attempting to initialize a -previously-initialized but as of yet undestroyed condition_variable." -How can this occur? +I propose Option 1 for C++0x for expediency. If someone wants to argue +for Option 2, they need to say what exactly they want compare_exchange +to mean in this case (IIRC, C++0x doesn't even assume IEEE 754).

    [ Summit: ]

    +
    -

    -Move to review. Proposed resolution: strike the device_or_resource_busy -error condition from the constructor of condition_variable. -

    -
      -
    • -This is a POSIX error that cannot occur in this interface because the -C++ interface does not separate declaration from initialization. -
      • -
    +Move to open. Blocked until concepts for atomics are addressed.

    [ -Batavia (2009-05): +Post Summit Anthony adds: ]

    -
    -We agree with the proposed resolution. -Move to Tentatively Ready. -
    - -

    Proposed resolution:

    +

    -Change 30.5.1 [thread.condition.condvar] p3: +Recommend NAD. C++0x does have std::atomic<float>, and both +compare_exchange_weak and compare_exchange_strong are well-defined in +this case. Maybe change the note in 29.6 [atomics.types.operations] paragraph 20 to:

    -
      -
    • ...
      • -
    • -device_or_resource_busy -- if attempting to initialize a -previously-initialized but as of yet undestroyed -condition_variable. -
      • -
    -
    +

    +[Note: The effect of the compare-and-exchange operations is +

    +
    if (!memcmp(object,expected,sizeof(*object)))
+    *object = desired;
+else
+    *expected = *object;
+
    +

    +This may result in failed comparisons for values that compare equal if +the underlying type has padding bits or alternate representations of +the same value. -- end note] +

    +
    +
    -
    -

    966. Various threading bugs #16

    -

    Section: 30.5.1 [thread.condition.condvar] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-22

    -

    View other active issues in [thread.condition.condvar].

    -

    View all other issues in [thread.condition.condvar].

    -

    View all issues with Open status.

    -

    Discussion:

    +

    Proposed resolution:

    -30.5.1 [thread.condition.condvar]: condition_variable::wait and -condition_variable::wait_until both have a postcondition that lock is -locked by the calling thread, and a throws clause that requires throwing -an exception if this postcondition cannot be achieved. How can the -implementation detect that this lock can never be obtained? +Change the note in 29.6 [atomics.types.operations] paragraph 20 to:

    -

    [ -Summit: -]

    - -
    -Move to open. Requires wording. Agreed this is an issue, and the -specification should not require detecting deadlocks. -
    +

    +[Note: The effect of the compare-and-exchange operations is +

    +
    if (*object == *expected !memcmp(object,expected,sizeof(*object)))
+    *object = desired;
+else
+    *expected = *object;
+
    +

    +This may result in failed comparisons for values that compare equal if +the underlying type has padding bits or alternate representations of +the same value. -- end note] +

    + -

    Proposed resolution:

    -

    967. Various threading bugs #17

    -

    Section: 30.3.1.2 [thread.thread.constr] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-22

    -

    View other active issues in [thread.thread.constr].

    -

    View all other issues in [thread.thread.constr].

    +

    924. structs with internal padding

    +

    Section: 29 [atomics] Status: Open + Submitter: Herb Sutter Opened: 2008-10-17 Last modified: 2009-03-22

    +

    View other active issues in [atomics].

    +

    View all other issues in [atomics].

    View all issues with Open status.

    Discussion:

    -the error handling for the constructor for condition_variable -distinguishes lack of memory from lack of other resources, but the error -handling for the thread constructor does not. Is this difference -intentional? +Right now, the compare_exchange_weak loop should rapidly converge on the +padding contents. But compare_exchange_strong will require a bit more +compiler work to ignore padding for comparison purposes. +

    +

    +Note that this isn't a problem for structs with no padding, and we do +already have one portable way to ensure that there is no padding that +covers the key use cases: Have elements be the same type. I suspect that +the greatest need is for a structure of two pointers, which has no +padding problem. I suspect the second need is a structure of a pointer +and some form of an integer. If that integer is intptr_t, there will be +no padding.

    - -

    [ -Beman has volunteered to provide proposed wording. -]

    - - - -

    Proposed resolution:

    +Related but separable issue: For unused bitfields, or other unused +fields for that matter, we should probably say it's the programmer's +responsibility to set them to zero or otherwise ensure they'll be +ignored by memcmp.

    +

    +Proposed resolutions: Using +atomic<struct-with-padding>::compare_exchange_strong should be either: +

    +
      +
    1. +ill-formed, or +
      2. +
    2. +well-defined. +
      3. +
    - - -
    -

    968. Various threading bugs #18

    -

    Section: 30.4.1 [thread.mutex.requirements] Status: Open - Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2009-03-22

    -

    View other active issues in [thread.mutex.requirements].

    -

    View all other issues in [thread.mutex.requirements].

    -

    View all issues with Open status.

    -

    Discussion:

    -30.4.1 [thread.mutex.requirements]: several functions are -required to throw exceptions "if the thread does not have the necessary -permission ...". "The necessary permission" is not defined. +I propose Option 1 for C++0x for expediency, though I'm not sure how to +say it. I would be happy with Option 2, which I believe would mean that +compare_exchange_strong would be implemented to avoid comparing padding +bytes, or something equivalent such as always zeroing out padding when +loading/storing/comparing. (Either implementation might require compiler +support.)

    [ Summit: ]

    +
    -Move to open. +Move to open. Blocked until concepts for atomics are addressed.
    -

    [ -Beman has volunteered to provide proposed wording. +Post Summit Anthony adds: ]

    +
    +The resoultion of LWG 923 should resolve this issue as well. +
    + +

    Proposed resolution:

    @@ -23627,260 +17165,387 @@ Beman has volunteered to provide proposed wording.

    -

    969. What happened to Library Issue 475?

    -

    Section: 25.3.4 [alg.foreach] Status: Tentatively NAD Editorial - Submitter: Stephan T. Lavavej Opened: 2009-01-12 Last modified: 2009-05-23

    -

    View other active issues in [alg.foreach].

    -

    View all other issues in [alg.foreach].

    -

    View all issues with Tentatively NAD Editorial status.

    +

    926. Sequentially consistent fences, relaxed operations and modification order

    +

    Section: 29.3 [atomics.order] Status: Open + Submitter: Anthony Williams Opened: 2008-10-19 Last modified: 2009-03-22

    +

    View all other issues in [atomics.order].

    +

    View all issues with Open status.

    Discussion:

    +

    Addresses UK 313

    +

    -Library Issue 475 has CD1 status, but the non-normative note in -N2723 -was removed in -N2798 -(25.3.4 [alg.foreach] in both drafts). +There was an interesting issue raised over on comp.programming.threads +today regarding the following example +

    + +
    // Thread 1:
+x.store(1, memory_order_relaxed);           // SX
+atomic_thread_fence(memory_order_seq_cst);  // F1
+y.store(1, memory_order_relaxed);           // SY1
+atomic_thread_fence(memory_order_seq_cst);  // F2
+r1 = y.load(memory_order_relaxed);          // RY
+
+// Thread 2:
+y.store(0, memory_order_relaxed);          // SY2
+atomic_thread_fence(memory_order_seq_cst); // F3
+r2 = x.load(memory_order_relaxed);         // RX
+
    + +

    +is the outcome r1 == 0 and r2 == 0 possible? +

    +

    +I think the intent is that this is not possible, but I am not sure the +wording guarantees that. Here is my analysis: +

    +

    +Since all the fences are SC, there must be a total order between them. +F1 must be before F2 in that order since they are in +the same thread. Therefore F3 is either before F1, +between F1 and F2 or after F2. +

    +

    +If F3 is after F2, then we can apply 29.3 [atomics.order]p5 from +N2798: +

    + +
    +For atomic operations A and B on an atomic object +M, where A modifies M and B takes +its value, if there are memory_order_seq_cst fences X +and Y such that A is sequenced before X, +Y is sequenced before B, and X precedes +Y in S, then B observes either the effects of +A or a later modification of M in its modification +order. +
    + +

    +In this case, A is SX, B is RX, the +fence X is F2 and the fence Y is F3, +so RX must see 1. +

    +

    +If F3 is before F2, this doesn't apply, but +F3 can therefore be before or after F1. +

    +

    +If F3 is after F1, the same logic applies, but this +time the fence X is F1. Therefore again, RX +must see 1. +

    +

    +Finally we have the case that F3 is before F1 +in the SC ordering. There are now no guarantees about RX, and +RX can see r2==0. +

    +

    +We can apply 29.3 [atomics.order]p5 again. This time, +A is SY2, B is RY, X is +F3 and Y is F1. Thus RY must observe +the effects of SY2 or a later modification of y in its +modification order. +

    +

    +Since SY1 is sequenced before RY, RY must +observe the effects of SY1 or a later modification of +y in its modification order. +

    +

    +In order to ensure that RY sees (r1==1), we must see +that SY1 is later in the modification order of y than +SY2. +

    +

    +We're now skating on thin ice. Conceptually, SY2 happens-before +F3, F3 is SC-ordered before F1, F1 +happens-before SY1, so SY1 is later in the +modification order M of y, and RY must see +the result of SY1 (r1==1). However, I don't think the +words are clear on that.

    [ -Batavia (2009-05): +Post Summit Hans adds: ]

    -
    -Move to NAD Editorial. -
    - -

    Proposed resolution:

    +

    -Restore the non-normative note. It might need to be expressed in terms of concepts. +In my (Hans') view, our definition of fences will always be weaker than +what particular hardware will guarantee. Memory_order_seq_cst fences +inherently don't guarantee sequential consistency anyway, for good +reasons (e.g. because they can't enforce a total order on stores). + Hence I don't think the issue demonstrates a gross failure to achieve +what we intended to achieve. The example in question is a bit esoteric. + Hence, in my view, living with the status quo certainly wouldn't be a +disaster either.

    - - - - - -
    -

    970. addressof overload unneeded

    -

    Section: 20.8.11.1 [object.addressof] Status: Tentatively Ready - Submitter: Howard Hinnant Opened: 2009-01-16 Last modified: 2009-05-23

    -

    View other active issues in [object.addressof].

    -

    View all other issues in [object.addressof].

    -

    View all issues with Tentatively Ready status.

    -

    Discussion:

    -20.8.11.1 [object.addressof] specifies: +In any case, we should probably add text along the lines of the +following between p5 and p6 in 29.3 [atomics.order]:

    - -
    template <ObjectType T> T* addressof(T& r);
-template <ObjectType T> T* addressof(T&& r);
-
    +
    +[Note: Memory_order_seq_cst only ensures sequential consistency for a +data-race-free program that uses exclusively memory_order_seq_cst +operations. Any use of weaker ordering will invalidate this guarantee +unless extreme care is used. In particular, memory_order_seq_cst fences +only ensure a total order for the fences themselves. They cannot, in +general, be used to restore sequential consistency for atomic operations +with weaker ordering specifications.] +

    -The two signatures are ambiguous when the argument is an lvalue. The -second signature seems not useful: what does it mean to take the -address of an rvalue? +Also see thread beginning at c++std-lib-23271.

    -

    [ -Post Summit: -]

    - - -
    -Recommend Review.

    [ -Batavia (2009-05): +Herve's correction: ]

    -We agree with the proposed resolution. -Move to Tentatively Ready. +

    +Minor point, and sorry for the knee jerk reaction: I admit to having +no knowledge of Memory_order_seq_cst, but my former boss (John Lakos) +has ingrained an automatic introspection on the use of "only". I +think you meant: +

    + +
    +[Note: Memory_order_seq_cst ensures sequential consistency only +for . . . . In particular, memory_order_seq_cst fences ensure a +total order only for . . . +
    +

    +Unless, of course, Memory_order_seq_cst really do nothing but ensure +sequential consistency for a data-race-free program that uses +exclusively memory_order_seq_cst operations. +

    +

    Proposed resolution:

    -Change 20.8.11.1 [object.addressof]: +Add a new paragraph after 29.3 [atomics.order]p5 that says

    -
    template <ObjectType T> T* addressof(T& r);
-template <ObjectType T> T* addressof(T&& r);
-
    - +
    +For atomic operations A and B on an atomic object +M, where A and B modify M, if there +are memory_order_seq_cst fences X and Y such +that A is sequenced before X, Y is sequenced +before B, and X precedes Y in S, +then B occurs later than A in the modifiction order of +M. +
    -

    971. Spurious diagnostic conversion function

    -

    Section: 19.5.2.6 [syserr.errcode.nonmembers] Status: Open - Submitter: Beman Dawes Opened: 2009-01-19 Last modified: 2009-05-23

    +

    929. Thread constructor

    +

    Section: 30.3.1.2 [thread.thread.constr] Status: Open + Submitter: Anthony Williams Opened: 2008-10-23 Last modified: 2009-07-18

    +

    View other active issues in [thread.thread.constr].

    +

    View all other issues in [thread.thread.constr].

    View all issues with Open status.

    Discussion:

    + +

    Addresses UK 323

    +

    -Anthony Williams raised the question in c++std-lib-22987 "why is there -std::make_error_code(std::errc)? What purpose does this serve?" +The thread constructor for starting a new thread with a function and +arguments is overly constrained by the signature requiring rvalue +references for func and args and the CopyConstructible requirements +for the elements of args. The use of an rvalue reference for the +function restricts the potential use of a plain function name, since +the type of the bound parameter will be deduced to be a function +reference and decay to pointer-to-function will not happen. This +therefore complicates the implementation in order to handle a simple +case. Furthermore, the use of rvalue references for args prevents the +array to pointer decay. Since arrays are not CopyConstructible or even +MoveConstructible, this essentially prevents the passing of arrays as +parameters. In particular it prevents the passing of string literals. +Consequently a simple case such as

    + +
    void f(const char*);
+std::thread t(f,"hello");
+
    +

    -The function make_error_code(errc e) is not required, since -make_error_condition(errc e) is the function that is needed for errc -conversions. make_error_code(errc e) appears to be a holdover from my -initial confusion over the distinction between POSIX and operating -systems that conform to the POSIX spec. +is ill-formed since the type of the string literal is const char[6].

    -

    [ -Post Summit: -]

    - +

    +By changing the signature to take all parameters by value we can +eliminate the CopyConstructible requirement and permit the use of +arrays, as the parameter passing semantics will cause the necessary +array-to-pointer decay. They will also cause the function name to +decay to a pointer to function and allow the implementation to handle +functions and function objects identically. +

    -
    -Recommend Review. -
    +

    +The new signature of the thread constructor for a function and +arguments is thus: +

    -

    [ -Batavia (2009-05): -]

    +
    template<typename F,typename... Args>
+thread(F,Args... args);
+
    -
    -The designer of the facility (Christopher Kohlhoff) -strongly disagrees that there is an issue here, -and especially disagrees with the proposed resolution. -Bill would prefer to be conservative and not apply this proposed resolution. -Move to Open, and recommend strong consideration for NAD status. -
    +

    +Since the parameter pack Args can be empty, the single-parameter +constructor that takes just a function by value is now redundant. +

    [ -2009-05-21 Beman adds: +Howard adds: ]

    -My mistake. Christopher and Bill are correct and the issue should be -NAD. The function is needed by users. -
    - - -

    Proposed resolution:

    -Change System error support 19.5 [syserr], Header <system_error> -synopsis, as indicated: +I agree with everything Anthony says in this issue. However I believe we +can optimize in such a way as to get the pass-by-value behavior with the +pass-by-rvalue-ref performance. The performance difference is that the latter +removes a move when passing in an lvalue.

    -
    error_code make_error_code(errc e);
-error_condition make_error_condition(errc e);
-
    -

    -Delete from Class error_code non-member functions -19.5.2.6 [syserr.errcode.nonmembers]: +This circumstance is very analogous to make_pair (20.3.3 [pairs]) +where we started with passing by const reference, changed to pass by value to +get pointer decay, and then changed to pass by rvalue reference, but modified with +decay<T> to retain the pass-by-value behavior. If we were to +apply the same solution here it would look like:

    -
    error_code make_error_code(errc e);
+
    template <class F> explicit thread(F f);
+template <class F, class ...Args> thread(F&& f, Args&&... args);
 
    
 
    
-Returns: error_code(static_cast<int>(e),
-generic_category).
+
    
+-4- Requires: F and each Ti in Args shall be CopyConstructible
+if an lvalue and otherwise MoveConstructible.
+INVOKE(f, w1, w2, ..., wN) (20.7.2 [func.require]) shall be a valid expression for
+some values w1, w2, ... , wN, where N == sizeof...(Args).
+
    
+
    
+-5- Effects: Constructs an object of type thread
+and executes INVOKE(f, t1, t2, ..., tN) in a new
+thread of execution, where t1, t2, ..., tN are the values in args....
+Constructs
+the following objects in memory which is accessible to a new thread of execution
+as if:
+
    
+
    typename decay<F>::type g(std::forward<F>(f));
+tuple<typename decay<Args>::type...> w(std::forward<Args>(args)...);
+
    
+
    
+The new thread of
+execution executes INVOKE(g, wi...) where the wi... refers
+to the elements stored in the tuple w.
+Any return value from g is ignored.
+If f terminates with an uncaught exception, std::terminate() shall be called.
+If the evaluation of INVOKE(g,  wi...) terminates
+with an uncaught exception, std::terminate() shall be called [Note:
+std::terminate() could be called before entering g. -- end note]. Any
+exception thrown before the evaluation of INVOKE has started shall be
+catchable in the calling thread.
+
    
 
    
 
    
 
-
-
-
-
-
-
    
-
    972. The term "Assignable" undefined but still in use
    
-
    Section: 17 [library] Status: Tentatively NAD Editorial
- Submitter: Niels Dekker Opened: 2009-01-07  Last modified: 2009-05-23
    
-
    View other active issues in [library].
    
-
    View all other issues in [library].
    
-
    View all issues with Tentatively NAD Editorial status.
    
-
    Discussion:
    
 
    
-Previous versions of the Draft had a table, defining the Assignable 
-requirement.  For example 
-N2134
-Table 79, "Assignable requirements". But I guess the term "Assignable" 
-is outdated by now, because the current Committee Draft provides 
-MoveAssignable, CopyAssignable, and TriviallyCopyAssignable concepts 
-instead. And as far as I can see, it no longer has a definition of 
-Assignable. (Please correct me if I'm wrong.) Still the word 
-"Assignable" is used in eight places in the Draft, 
-N2800.
+Text referring to when terminate() is called was contributed by Ganesh.
 
    
 
-
    
-Are all of those instances of "Assignable" to be replaced by "CopyAssignable"? 
-
    
+

    [ Batavia (2009-05): ]

    -Move to NAD Editorial. +We agree with the proposed resolution, +but would like the final sentence to be reworded +since "catchable" is not a term of art (and is used nowhere else).
    +

    [ +2009-07 Frankfurt: +]

    -

    Proposed resolution:

    +

    -Change Exception Propagation 18.8.5 [propagation]: +This is linked to +N2901.

    -
    -exception_ptr shall be DefaultConstructible, CopyConstructible, -CopyAssignable and EqualityComparable. -
    -

    -Change Class template reference_wrapper 20.7.5 [refwrap]: +Howard to open a separate issue to remove (1176).

    -
    -reference_wrapper<T> is a CopyConstructible and CopyAssignable wrapper around a reference to an object of type T. -

    -Change Placeholders 20.7.12.1.4 [func.bind.place]: +In Frankfurt there is no consensus for removing the variadic constructor.

    -
    -It is implementation defined whether placeholder types are CopyAssignable. CopyAssignable placeholders' copy assignment operators shall not throw exceptions.
    + + + +

    Proposed resolution:

    +

    +Modify the class definition of std::thread in 30.3.1 [thread.thread.class] to remove the +following signature: +

    + +
    template<class F> explicit thread(F f);
+template<class F, class ... Args> explicit thread(F&& f, Args&& ... args);
+
    +

    -Change Class template shared_ptr 20.8.13.2 [util.smartptr.shared]: +Modify 30.3.1.2 [thread.thread.constr] to replace the constructors prior to paragraph 4 with +the single constructor as above. Replace paragraph 4 - 6 with the +following:

    +
    -Specializations of shared_ptr shall be CopyConstructible, CopyAssignable, and LessThanComparable... -

    -Change Class template weak_ptr 20.8.13.3 [util.smartptr.weak]: +-4- Requires: F and each Ti in Args shall be CopyConstructible +if an lvalue and otherwise MoveConstructible. +INVOKE(f, w1, w2, ..., wN) (20.7.2 [func.require]) shall be a valid expression for +some values w1, w2, ... , wN, where N == sizeof...(Args).

    -
    -Specializations of weak_ptr shall be CopyConstructible, CopyAssignable, and LessThanComparable... -

    -Change traits typedefs 21.2.2 [char.traits.typedefs] (note: including deletion of reference to 23.1!): +-5- Effects: Constructs an object of type thread +and executes INVOKE(f, t1, t2, ..., tN) in a new +thread of execution, where t1, t2, ..., tN are the values in args.... +Constructs +the following objects:

    -
    -Requires: state_type shall meet the requirements of CopyAssignable (23.1), CopyConstructible (20.1.8), and DefaultConstructible types. -
    +
    typename decay<F>::type g(std::forward<F>(f));
+tuple<typename decay<Args>::type...> w(std::forward<Args>(args)...);
+

    -Change Class seed_seq 26.5.7.1 [rand.util.seedseq] (note again: including deletion of reference to 23.1!): +and executes INVOKE(g, wi...) in a new thread of execution. +These objects shall be destroyed when the new thread of execution completes. +Any return value from g is ignored. +If f terminates with an uncaught exception, std::terminate() shall be called. +If the evaluation of INVOKE(g, wi...) terminates +with an uncaught exception, std::terminate() shall be called [Note: +std::terminate() could be called before entering g. -- end note]. Any +exception thrown before the evaluation of INVOKE has started shall be +catchable in the calling thread.

    -
    -In addition to the requirements set forth below, instances of -seed_seq shall meet the requirements of CopyConstructible (20.1.8) and of CopyAssignable (23.1). -
    -

    -Note: The proposed resolution of this issue does not deal with the -instance of the term "Assignable" in D.9.1 [auto.ptr], as this is dealt -with more specifically by LWG 973, "auto_ptr characteristics", submitted -by Maarten Hilferink. +-6- Synchronization: The invocation of the constructor happens before the +invocation of f g.

    +
    @@ -23888,766 +17553,858 @@ by Maarten Hilferink.
    -

    973. auto_ptr characteristics

    -

    Section: D.9.1 [auto.ptr] Status: Tentatively NAD Editorial - Submitter: Maarten Hilferink Opened: 2009-01-21 Last modified: 2009-05-23

    -

    View other active issues in [auto.ptr].

    -

    View all other issues in [auto.ptr].

    -

    View all issues with Tentatively NAD Editorial status.

    +

    930. Access to std::array data as built-in array type

    +

    Section: 23.3.1 [array] Status: Review + Submitter: Niels Dekker Opened: 2008-11-17 Last modified: 2009-07-31

    +

    View other active issues in [array].

    +

    View all other issues in [array].

    +

    View all issues with Review status.

    Discussion:

    +

    -I think that the Note of D.9.1 [auto.ptr], paragraph 3 needs a rewrite -since "Assignable" is no longer defined as a concept. -The relationship of auto_ptr with the new CopyAssignable, MoveAssignable, - and MoveConstructible concepts should be clarified. -Furthermore, since the use of auto_ptr is depreciated anyway, - we can also omit a description of its intended use. +The Working Draft (N2798) allows access to the elements of +std::array by its data() member function:

    -

    [ -Batavia (2009-05): -]

    -
    -We agree with the intent of the proposed resolution. -Move to NAD Editorial. -
    +
    23.2.1.4 array::data [array.data]
    +
     T *data();
+ const T *data() const;
+
    +
    1. + Returns: elems. +
    +
    -

    Proposed resolution:

    -Change D.9.1 [auto.ptr], paragraph 3: +Unfortunately, the result of std::array::data() cannot be bound +to a reference to a built-in array of the type of array::elems. +And std::array provides no other way to get a reference to +array::elems. +This hampers the use of std::array, for example when trying to +pass its data to a C style API function:

    -
    -The auto_ptr provides a semantics of strict ownership. An -auto_ptr owns the ob ject it holds a pointer to. Copying an -auto_ptr copies the pointer and transfers ownership to the -destination. If more than one auto_ptr owns the same ob ject at -the same time the behavior of the program is undefined. [Note: -The uses of auto_ptr include providing temporary -exception-safety for dynamically allocated memory, passing ownership of -dynamically allocated memory to a function, and returning dynamically -allocated memory from a function. -auto_ptr does not meet the -CopyConstructible and Assignable requirements for -standard library container elements and thus instantiating a standard -library container with an auto_ptr results in undefined -behavior. - -Instances of auto_ptr shall -meet the MoveConstructible and MoveAssignable -requirements, but do not meet the CopyConstructible and -CopyAssignable requirements. --- end note] -
    +
     // Some C style API function. 
+ void set_path( char (*)[MAX_PATH] );
 
+ std::array<char,MAX_PATH> path;
+ set_path( path.data() );  // error
+ set_path( &(path.data()) );  // error
+
    +

    +Another example, trying to pass the array data to an instance of another +C++ class: +

    +
     // Represents a 3-D point in space.
+ class three_d_point {
+ public:
+   explicit three_d_point(const double (&)[3]); 
+ };
 
+ const std::array<double,3> coordinates = { 0, 1, 2 };
+ three_d_point point1( coordinates.data() );  // error.
+ three_d_point point2( *(coordinates.data()) );  // error.
+
    -
    -

    974. duration<double> should not implicitly convert to duration<int>

    -

    Section: 20.9.3.1 [time.duration.cons] Status: Tentatively Ready - Submitter: Howard Hinnant Opened: 2009-01-21 Last modified: 2009-05-23

    -

    View all issues with Tentatively Ready status.

    -

    Discussion:

    -The following code should not compile because it involves implicit truncation -errors (against the design philosophy of the duration library). +A user might be tempted to use std::array::elems instead, but +doing so isn't recommended, because std::array::elems is "for +exposition only". Note that Boost.Array users might already use +boost::array::elems, as its documentation doesn't explicitly +state that boost::array::elems is for exposition only: +http://www.boost.org/doc/libs/1_36_0/doc/html/boost/array.html

    - -
    duration<double> d(3.5);
-duration<int> i = d;  // implicit truncation, should not compile
-
    -

    -This intent was codified in the example implementation which drove this proposal -but I failed to accurately translate the code into the specification in this -regard. +I can think of three options to solve this issue:

    - -

    [ -Batavia (2009-05): -]

    - -
    +
    1. +Remove the words "exposition only" from the definition of +std::array::elems, as well as the note saying that "elems is +shown for exposition only." +
    2. +Change the signature of std::array::data(), so that it would +return a reference to the built-in array, instead of a pointer to its +first element. +
    3. +Add extra member functions, returning a reference to the built-in array. +

    -We agree with the proposed resolution. +Lawrence Crowl wrote me that it might be better to leave +std::array::elems "for exposition only", to allow alternate +representations to allocate the array data dynamically. This might be +of interest to the embedded community, having to deal with very limited +stack sizes.

    -Move to Tentatively Ready. +The second option, changing the return type of +std::array::data(), would break backward compatible to current +Boost and TR1 implementations, as well as to the other contiguous +container (vector and string) in a very subtle way. +For example, the following call to std::swap currently swap two +locally declared pointers (data1, data2), for any container +type T that has a data() member function. When +std::array::data() is changed to return a reference, the +std::swap call may swap the container elements instead.

    -
    +
     template <typename T>
+ void func(T& container1, T& container2)
+ {
+   // Are data1 and data2 pointers or references?
+   auto data1 = container1.data();
+   auto data2 = container2.data();
+
+   // Will this swap two local pointers, or all container elements?
+   std::swap(data1, data2);
+ }
+
    -

    Proposed resolution:

    -Change 20.9.3.1 [time.duration.cons], p4: +The following concept is currently satisfied by all contiguous +containers, but it no longer is for std::array, when +array::data() +is changed to return a reference (tested on ConceptGCC Alpha 7):

    -
    -
    template <class Rep2, class Period2> 
-  duration(const duration<Rep2, Period2>& d);
+
     auto concept ContiguousContainerConcept<typename T>
+ {
+   typename value_type = typename T::value_type;
+   const value_type * T::data() const;
+ }
 
    
-
    
--4- Requires: treat_as_floating_point<rep>::value
-shall be true or both ratio_divide<Period2,
-period>::type::den shall be 1
-and treat_as_floating_point<Rep2>::value
-shall be false.
-Diagnostic required.
-[Note: This requirement prevents implicit truncation error when
-converting between integral-based duration types. Such a
-construction could easily lead to confusion about the value of the
-duration. -- end note]
-
    
-
    - - +

    +Still it's worth considering having std::array::data() return a +reference, because it might be the most intuitive option, from a user's +point of view. Nicolai Josuttis (who wrote boost::array) +mailed me that he very much prefers this option. +

    +

    +Note that for this option, the definition of data() would also +need to be revised for zero-sized arrays, as its return type cannot be a +reference to a zero-sized built-in array. Regarding zero-sized array, +data() could throw an exception. Or there could be a partial +specialization of std::array where data() returns +T* or gets removed. +

    +

    +Personally I prefer the third option, adding a new member function to +std::array, overloaded for const and non-const access, +returning a reference to the built-in array, to avoid those compatible +issues. I'd propose naming the function std::array::c_array(), +which sounds intuitive to me. Note that boost::array already +has a c_array() member, returning a pointer, but Nicolai told +me that this one is only there for historical reasons. (Otherwise a name +like std::array::native_array() or +std::array::builtin_array() would also be fine with me.) +According to my proposed resolution, a zero-sized std::array does not need +to have c_array(), while it is still required to have +data() functions. +

    +

    [ +Post Summit: +]

    -
    -

    975. is_convertible cannot be instantiated for non-convertible types

    -

    Section: 20.6.5 [meta.rel] Status: Tentatively Ready - Submitter: Daniel Krügler Opened: 2009-01-25 Last modified: 2009-05-23

    -

    View other active issues in [meta.rel].

    -

    View all other issues in [meta.rel].

    -

    View all issues with Tentatively Ready status.

    -

    Discussion:

    -Addresses UK 206 +

    -Related to 1114. +Alisdair: Don't like p4 suggesting implementation-defined behaviour.

    -

    -The current specification of std::is_convertible (reference is draft -N2798) -is basically defined by 20.6.5 [meta.rel]/4: +Walter: What about an explicit conversion operator, instead of adding +the new member function?

    - -

    -In order to instantiate the template is_convertible<From, -To>, the following code shall be well formed: +Alisdair: Noodling about:

    +
    template<size_t N, ValueType T>
+struct array
+{
+  T elems[N];
 
-
    template <class T>
-  typename add_rvalue_reference<T>::type create();
+// fantasy code starts here
 
-To test() {
-  return create<From>();
-}
-
    
+// crazy decltype version for grins only
+//requires True<(N>0)>
+//explict operator decltype(elems) & () { return elems; }
 
-
    
-[Note: This requirement gives well defined results for reference
-types, void types, array types, and function types. --end note]
-
    
-
    +// conversion to lvalue ref +requires True<(N>0)> +explict operator T(&)[N] () & { return elems; } -

    -The first sentence can be interpreted, that e.g. the expression -

    +// conversion to const lvalue ref +requires True<(N>0)> +explict operator const T(&)[N] () const & { return elems; } + +// conversion to rvalue ref using ref qualifiers +requires True<(N>0)> +explict operator T(&&)[N] () && { return elems; } + +// fantasy code ends here -
    std::is_convertible<double, int*>::value
+explicit operator bool() { return true; }
+};

    -is ill-formed because std::is_convertible<double, int*> could not be -instantiated, or in more general terms: The wording requires that -std::is_convertible<X, Y> cannot be instantiated for otherwise valid -argument types X and Y if X is not convertible to Y. +This seems legal but odd. Jason Merrill says currently a CWG issue 613 +on the non-static data member that fixes the error that current G++ +gives for the non-explicit, non-conceptualized version of this. Verdict +from human compiler: seems legal. +

    +

    +Some grumbling about zero-sized arrays being allowed and supported.

    -

    -This semantic is both unpractical and in contradiction to what the last type -traits paper -N2255 -proposed: +Walter: Would this address the issue? Are we inclined to go this route?

    - -

    -If the following test function is well formed code b -is true, else it is false. +Alan: What would usage look like?

    +
    // 3-d point in space
+struct three_d_point
+{
+  explicit three_d_point(const double (&)[3]);
+};
 
-
    template <class T>
-  typename add_rvalue_reference<T>::type create();
+void sink(double*);
 
-To test() {
-  return create<From>();
-}
+const std::array<double, 3> coordinates = { 0, 1, 2 };
+three_d_point point1( coordinates.data() ); //error
+three_d_point point2( *(coordinates.data()) ); // error
+three_d_point point3( coordinates ); // yay!
+
+sink(cooridinates); // error, no conversion
 
    
 
 
    
-[Note: This definition gives well defined results for reference
-types, void types, array types, and function types. --end note]
+Recommended Open with new wording. Take the required clause and add the
+explicit conversion operators, not have a typedef. At issue still is use
+decltype or use T[N]. In favour of using T[N], even though use of
+decltype is specially clever.
 
    
+

    [ -Post Summit: +Post Summit, further discussion in the thread starting with c++std-lib-23215. +]

    + + +

    [ +2009-07 post-Frankfurt (Saturday afternoon group): ]

    -Jens: Checking that code is well-formed and then returning true/false -sounds like speculative compilation. John Spicer would really dislike -this. Please find another wording suggesting speculative compilation. +The idea to resolve the issue by adding explicit conversion operators +was abandoned, because it would be inconvenient to use, especially when +passing the array to a template function, as mentioned by Daniel. So we +reconsidered the original proposed resolution, which appeared +acceptable, except for its proposed changes to 23.3.1.6 [array.zero], which +allowed c_array_type and c_array() to be absent for a zero-sized array. +Alisdair argued that such wording would disallow certain generic use +cases. New wording for 23.3.1.6 [array.zero] was agreed upon (Howard: and +is reflected in the proposed resolution).

    -Recommend Open. +Move to Review

    [ -Post Summit, Howard adds: +2009-07-31 Alisdair adds: ]

    -John finds the following wording clearer: +I will be unhappy voting the proposed resolution for 930 past review +until we have implementation experience with reference qualifiers. +Specifically, I want to understand the impact of the missing overload +for const && (if any.)

    -
    - - - - - - - - - - -
    TemplateConditionComments
    template <class From, class To>
    struct is_convertible;    		see belowFrom and To shall be complete types, arrays of unknown bound, -or (possibly cv-qualified) void types.

    -Given the following function prototype: +If we think the issue is important enough it might be worthwhile +stripping the ref qualifiers for easy progress next meeting, and opening +yet another issue to put them back with experience.

    -
    template <class T>
-  typename add_rvalue_reference<T>::type create();
-
    -

    -is_convertible<From, To>::value shall be true if the -return expression in the following code would be well-formed, including -any implicit conversions to the return type of the function, else -is_convertible<From, To>::value shall be false. +Recommend deferring any decision on splitting the issue until we get LWG +feedback next meeting - I may be the lone dissenting voice if others are +prepared to proceed without it.

    +
    -
    To test() {
-  return create<From>();
-}
-
    -
    +

    Proposed resolution:

    +

    +Add to the template definition of array, 23.3.1 [array]/3: +

    +
    +
    
+typedef T c_array_type[N];
+c_array_type & c_array() &;
+c_array_type && c_array() &&;
+const c_array_type & c_array() const &;
+
+
    -Original proposed wording: -

    -In 20.6.5 [meta.rel]/4 change: +Add the following subsection to 23.3.1 [array], after 23.3.1.4 [array.data]:

    -In order to instantiate the template is_convertible<From, To>, the -following code shall be well formed If the following code -is well formed is_convertible<From, To>::value is true, otherwise -false:[..] +
    23.2.1.5 array::c_array [array.c_array]
    + 
    
+c_array_type & c_array() &;
+c_array_type && c_array() &&;
+const c_array_type & c_array() const &;
+
    +
    +

    +Returns: elems. +

    +
    +
    -

    Revision 2

    -

    -In 20.6.5 [meta.rel] change: +Change Zero sized arrays 23.3.1.6 [array.zero]:

    - - - - - - - - - - -
    TemplateConditionComments
    .........
    template <class From, class To>
    struct is_convertible;    		 -The code set out below shall be well formed. -see belowFrom and To shall be complete types, arrays of unknown bound, -or (possibly cv-qualified) void types.
    +

    -2- ...

    + +

    +The type c_array_type is unspecified for a zero-sized array. +

    --4- In order to instantiate the template is_convertible<From, To>, the -following code shall be well formed: -Given the following function prototype: +-3- The effect of calling c_array(), front(), or +back() for a zero-sized array is implementation defined.

    +
    -
    template <class T> 
-  typename add_rvalue_reference<T>::type create();
-
    -

    -is_convertible<From, To>::value inherits either directly or -indirectly from true_type if the -return expression in the following code would be well-formed, including -any implicit conversions to the return type of the function, else -is_convertible<From, To>::value inherits either directly or -indirectly from false_type. -

    -
    To test() { 
-  return create<From>(); 
-}
-
    + + + +
    +

    932. unique_ptr(pointer p) for pointer deleter types

    +

    Section: 20.8.9.2.1 [unique.ptr.single.ctor] Status: Open + Submitter: Howard Hinnant Opened: 2008-11-26 Last modified: 2009-07-27

    +

    View other active issues in [unique.ptr.single.ctor].

    +

    View all other issues in [unique.ptr.single.ctor].

    +

    View all issues with Open status.

    +

    Discussion:

    + +

    Addresses US 79

    -[Note: This requirement gives well defined results for reference types, -void types, array types, and function types. -- end note] +20.8.9.2.1 [unique.ptr.single.ctor]/5 no longer requires for D +not to be a pointer type. I believe this restriction was accidently removed +when we relaxed the completeness reuqirements on T. The restriction +needs to be put back in. Otherwise we have a run time failure that could +have been caught at compile time:

    -
    -
    +
    {
+unique_ptr<int, void(*)(void*)> p1(malloc(sizeof(int)));  // should not compile
+}  // p1.~unique_ptr() dereferences a null function pointer
+unique_ptr<int, void(*)(void*)> p2(malloc(sizeof(int)), free);  // ok
+

    [ -Batavia (2009-05): +Post Summit: ]

    +
    -We agree with the proposed resolution. -Move to Tentatively Ready. +Recommend Tentatively Ready.
    +

    [ +2009-07 Frankfurt +]

    -

    Proposed resolution:

    - -

    -In 20.6.5 [meta.rel] change: -

    +Moved from Tentatively Ready to Open only because the wording needs to be +improved for enable_if type constraining, possibly following Robert's +formula. +
    - - - - - - - - - - -
    TemplateConditionComments
    .........
    template <class From, class To>
    struct is_convertible;    		 -The code set out below shall be well formed. -see belowFrom and To shall be complete types, arrays of unknown bound, -or (possibly cv-qualified) void types.
    - -

    --4- In order to instantiate the template is_convertible<From, To>, the -following code shall be well formed: -Given the following function prototype: -

    +

    [ +2009-07 Frankfurt: +]

    -
    template <class T> 
-  typename add_rvalue_reference<T>::type create();
-
    +

    -the predicate condition for a template specialization -is_convertible<From, To> shall be satisfied, if and only -if the return expression in the following code would be well-formed, -including any implicit conversions to the return type of the -function. +We need to consider whether some requirements in the Requires paragraphs +of [unique.ptr] should instead be Remarks.

    - -
    To test() { 
-  return create<From>(); 
-}
-
    -

    -[Note: This requirement gives well defined results for reference types, -void types, array types, and function types. — end note] +Leave Open. Howard to provide wording, and possibly demonstrate how this +can be implemented using enable_if.

    -
    +

    [ +2009-07-27 Howard adds: +]

    - - -
    -

    976. Class template std::stack should be movable

    -

    Section: 23.3.5.3.1 [stack.defn] Status: Tentatively Ready - Submitter: Daniel Krügler Opened: 2009-02-01 Last modified: 2009-05-23

    -

    View all issues with Tentatively Ready status.

    -

    Discussion:

    +

    -The synopsis given in 23.3.5.3.1 [stack.defn] does not show up +The two constructors to which this issue applies are not easily constrained +with enable_if as they are not templated:

    -
    requires MoveConstructible<Cont> stack(stack&&);
-requires MoveAssignable<Cont> stack& operator=(stack&&);
+
    unique_ptr();
+explicit unique_ptr(pointer p);
 
    
 
 
    
-although the other container adaptors do provide corresponding
-members.
+To "SFINAE" these constructors away would take heroic effort such as specializing
+the entire unique_ptr class template on pointer deleter types.  There
+is insufficient motivation for such heroics.  Here is the expected and
+reasonable implementation for these constructors:
 
    
 
-
    [
-Batavia (2009-05):
-]
    
+
    unique_ptr()
+    : ptr_(pointer())
+    {
+        static_assert(!is_pointer<deleter_type>::value,
+            "unique_ptr constructed with null function pointer deleter");
+    }
+explicit unique_ptr(pointer p)
+    : ptr_(p)
+    {
+        static_assert(!is_pointer<deleter_type>::value,
+            "unique_ptr constructed with null function pointer deleter");
+    }
+
    
 
-
    
 
    
-We agree with the proposed resolution.
+I.e. just use static_assert to verify that the constructor is not
+instantiated with a function pointer for a deleter.  The compiler will automatically
+take care of issuing a diagnostic if the deleter is a reference type (uninitialized
+reference error).
 
    
+
 
    
-Move to Tentatively Ready.
+In keeping with our discussions in Frankfurt, I'm moving this requirement on
+the implementation from the Requires paragraph to a Remarks paragraph.
 
    
+
 
    
 
 
+
 
    Proposed resolution:
    
 
    
-In the class stack synopsis of 23.3.5.3.1 [stack.defn] insert:
+Change the description of the default constructor in 20.8.9.2.1 [unique.ptr.single.ctor]:
 
    
 
-
    template <ObjectType T, StackLikeContainer Cont = deque<T> > 
-  requires SameType<Cont::value_type, T> 
-        && NothrowDestructible<Cont> 
-class stack { 
-public: 
-   ...
-   requires CopyConstructible<Cont> explicit stack(const Cont&); 
-   requires MoveConstructible<Cont> explicit stack(Cont&& = Cont()); 
-   requires MoveConstructible<Cont> stack(stack&&);
-   requires MoveAssignable<Cont> stack& operator=(stack&&);
-   template <class Alloc> 
-     requires Constructible<Cont, const Alloc&> 
-     explicit stack(const Alloc&);
-   ...
-};
-
    
+
    unique_ptr();
+
    
+
    
+
    
+-1- Requires: D shall be default constructible, and that construction
+shall not throw an exception. D shall 
+not be a reference type or pointer type (diagnostic required).
+
    
+
    ...
    
+Remarks: A diagnostic shall be emitted if this constructor is instantiated
+when D is a pointer type or reference type.
+
    
+
    
 
 
    
-[Remark: This change should be done in sync with the resolution of
-paper
-N2819]
+Add  after 20.8.9.2.1 [unique.ptr.single.ctor]/8:
 
    
 
+
    unique_ptr(pointer p);
+
    
+
    
+
    ...
    
+Remarks: A diagnostic shall be emitted if this constructor is instantiated
+when D is a pointer type or reference type.
+
    
+
    
 
 
 
 
 
 
    
-
    977. insert iterators inefficient for expensive to move types
    
-
    Section: 24.7 [insert.iterators] Status: Open
- Submitter: Howard Hinnant Opened: 2009-02-02  Last modified: 2009-05-23
    
-
    View other active issues in [insert.iterators].
    
-
    View all other issues in [insert.iterators].
    
+
    933. Unique_ptr defect
    
+
    Section: 20.8.9.2.5 [unique.ptr.single.modifiers] Status: Open
+ Submitter: Alisdair Meredith Opened: 2008-11-27  Last modified: 2009-05-23
    
+
    View all other issues in [unique.ptr.single.modifiers].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-The new concepts for the insert iterators mandate an extra copy when
-inserting an lvalue:
+If we are supporting stateful deleters, we need an overload for
+reset that
+takes a deleter as well.
 
    
 
-
    requires CopyConstructible<Cont::value_type>
-  back_insert_iterator<Cont>& 
-  operator=(const Cont::value_type& value);
-
    
-
    
--1- Effects: push_back(*container, Cont::value_type(value));
-
    
-
    
+
    void reset( pointer p, deleter_type d);
+
    
 
 
    
-The reason is to convert value into an rvalue because the current
-BackInsertionContainer concept only handles push_back-ing
-rvalues:
+We probably need two overloads to support move-only deleters, and
+this
+sounds uncomfortably like the two constructors I have been ignoring
+for
+now...
 
    
 
-
    concept BackInsertionContainer<typename C> : Container<C> { 
-  void push_back(C&, value_type&&); 
-}
-
    
+
    [
+Batavia (2009-05):
+]
    
+
+
    
+
    
+Howard comments that we have the functionality via move-assigment.
+
    
+
    
+Move to Open.
+
    
+
    
+
 
+
    Proposed resolution:
    
 
    
-Without the conversion of value to an rvalue, the assignment operator
-fails to concept check.
 
    
 
+
+
+
+
+
    
+
    934. duration is missing operator%
    
+
    Section: 20.9.3 [time.duration] Status: Ready
+ Submitter: Terry Golubiewski Opened: 2008-11-30  Last modified: 2009-07-27
    
+
    View other active issues in [time.duration].
    
+
    View all other issues in [time.duration].
    
+
    View all issues with Ready status.
    
+
    Discussion:
    
+
+
    Addresses US 81
    
+
 
    
-A solution is to modify the BackInsertionContainer concept so that
-the client can pass in the parameter type for push_back similar to
-what is already done for the OutputIterator concept:
+duration is missing operator%.  This operator is convenient
+for computing where in a time frame a given duration lies.  A
+motivating example is converting a duration into a "broken-down"
+time duration such as hours::minutes::seconds:
 
    
 
-
    concept BackInsertionContainer<typename C, typename Value = C::value_type&&>
-  : Container<C> { 
-     void push_back(C&, Value); 
-}
+
    class ClockTime
+{
+    typedef std::chrono::hours hours;
+    typedef std::chrono::minutes minutes;
+    typedef std::chrono::seconds seconds;
+public:
+    hours hours_;
+    minutes minutes_;
+    seconds seconds_;
+
+    template <class Rep, class Period>
+      explicit ClockTime(const std::chrono::duration<Rep, Period>& d)
+        : hours_  (std::chrono::duration_cast<hours>  (d)),
+          minutes_(std::chrono::duration_cast<minutes>(d % hours(1))),
+          seconds_(std::chrono::duration_cast<seconds>(d % minutes(1)))
+          {}
+};
 
    
 
-
    
-This allows the assignment operator to be adjusted appropriately:
-
    
+
    [
+Summit:
+]
    
+
 
-
    requires BackInsertionContainer<Cont, Cont::value_type const&> &&
-         CopyConstructible<Cont::value_type>
-  back_insert_iterator<Cont>& 
-  operator=(const Cont::value_type& value);
-
    
 
    
--1- Effects: push_back(*container, value);
-
    
+Agree except that there is a typo in the proposed resolution. The member
+operators should be operator%=.
 
    
 
 
    [
-We may want to propagate this fix to other concepts such as StackLikeContainer.
+Batavia (2009-05):
 ]
    
 
+
    
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
    
 
 
    [
-Solution and wording collaborated on by Doug and Howard.
+2009-07 Frankfurt
 ]
    
 
 
+
    
+Moved from Tentatively Ready to Open only because the wording needs to be
+improved for enable_if type constraining, possibly following Robert's
+formula.
+
    
+
 
    [
-Batavia (2009-05):
+2009-07 Frankfurt:
 ]
    
 
+
 
    
 
    
-Howard notes that "these operations behaved efficiently until concepts were added."
-
    
-
    
-Alisdair is uncertain that the proposed resolution is syntactically correct.
+Howard to open a separate issue (1177) to handle the removal of member
+functions from overload sets, provide wording, and possibly demonstrate
+how this can be implemented using enable_if (see 947).
 
    
 
    
-Move to Open, and recommend the issue be deferred until after the next
-Committee Draft is issued.
+Move to Ready.
 
    
 
    
 
 
+
 
    Proposed resolution:
    
 
    
-Change 23.2.6.1 [container.concepts.free]:
+Add to the synopsis in 20.9 [time]:
 
    
 
-
    
-
    concept FrontInsertionContainer<typename C, typename Value = C::value_type&&>
-    : Container<C> { 
-  void push_front(C&, value_type&& Value); 
-
-  axiom FrontInsertion(C c, value_type Value x) { 
-    x == (push_front(c, x), front(c)); 
-  } 
-}
-
    
-
-
    ...
    
+
    template <class Rep1, class Period, class Rep2>
+  duration<typename common_type<Rep1, Rep2>::type, Period>
+  operator%(const duration<Rep1, Period>& d, const Rep2& s);
+template <class Rep1, class Period1, class Rep2, class Period2>
+  typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
+  operator%(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+
    
 
-
    concept BackInsertionContainer<typename C, typename Value = C::value_type&&>
-    : Container<C> { 
-  void push_back(C&, value_type&& Value); 
-}
-
    
+
    
+Add to the synopsis of duration in 20.9.3 [time.duration]:
+
    
 
-
    ...
    
+
    template <class Rep, class Period = ratio<1>>
+class duration {
+public:
+  ...
+  duration& operator%=(const rep& rhs);
+  duration& operator%=(const duration& d);
+  ...
+};
+
    
 
-
    concept InsertionContainer<typename C, typename Value = C::value_type&&>
-    : Container<C> { 
-  iterator insert(C&, const_iterator, value_type&& Value); 
+
    
+Add to 20.9.3.3 [time.duration.arithmetic]:
+
    
 
-  axiom Insertion(C c, const_iterator position, value_type Value v) { 
-    v == *insert(c, position, v); 
-  } 
-}
+
    
+
    duration& operator%=(const rep& rhs);
 
    
+
    
+
    
+Effects: rep_ %= rhs.
+
    
+
    
+Returns: *this.
+
    
+
    
 
+
    duration& operator%=(const duration& d);
+
    
+
    
+
    
+Effects: rep_ %= d.count().
+
    
+
    
+Returns: *this.
+
    
+
    
 
    
 
 
    
-Change 23.2.6.2 [container.concepts.member]:
+Add to 20.9.3.5 [time.duration.nonmember]:
 
    
 
 
    
-
    auto concept MemberFrontInsertionContainer<typename C, typename Value = C::value_type&&>
-    : MemberContainer<C> { 
-  void C::push_front(value_type&& Value); 
 
-  axiom MemberFrontInsertion(C c, value_type Value x) { 
-    x == (c.push_front(x), c.front()); 
-  } 
-}
+
    template <class Rep1, class Period, class Rep2>
+  duration<typename common_type<Rep1, Rep2>::type, Period>
+  operator%(const duration<Rep1, Period>& d, const Rep2& s);
 
    
+
    
+
    
+Requires: Rep2 shall be implicitly convertible to CR(Rep1, Rep2) and
+Rep2 shall not be an instantiation of duration. Diagnostic required.
+
    
+
    
+Returns: duration<CR, Period>(d) %= s.
+
    
+
    
 
-
    ...
    
-
-
    auto concept MemberBackInsertionContainer<typename C, typename Value = C::value_type&&>
-    : MemberContainer<C> { 
-  void C::push_back(value_type&& Value); 
-}
+
    template <class Rep1, class Period1, class Rep2, class Period2>
+  typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
+  operator%(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
 
    
+
    
+
    
+Returns: common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type(lhs) %= rhs.
+
    
+
    
+
+
    
 
-
    ...
    
 
-
    auto concept MemberInsertionContainer<typename C, typename Value = C::value_type&&>
-    : MemberContainer<C> { 
-  iterator C::insert(const_iterator, value_type&& Value); 
 
-  axiom MemberInsertion(C c, const_iterator position, value_type Value v) { 
-    v == *c.insert(position, v); 
-  } 
-}
-
    
-
    
 
+
+
+
    
+
    935. clock error handling needs to be specified
    
+
    Section: 20.9.5 [time.clock] Status: Open
+ Submitter: Beman Dawes Opened: 2008-11-24  Last modified: 2009-05-23
    
+
    View all issues with Open status.
    
+
    Discussion:
    
 
    
-Change 23.2.6.3 [container.concepts.maps]:
+Each of the three clocks specified in Clocks 20.9.5 [time.clock]
+provides the member function:
 
    
 
-
    
-
    template <MemberFrontInsertionContainer C, typename Value = C::value_type&&> 
-concept_map FrontInsertionContainer<C, Value> { 
-  typedef Container<C>::value_type value_type;
-
-  void push_front(C& c, value_type&& Value v) { c.push_front(static_cast<value_type&& Value>(v)); } 
-}
-
    
+
    static time_point now();
+
    
 
-
    ...
    
+
    
+The semantics specified by Clock requirements 20.9.1 [time.clock.req]
+make no mention of error handling. Thus the function may throw bad_alloc
+or an implementation-defined exception (17.6.4.10 [res.on.exception.handling]
+paragraph 4).
+
    
 
-
    template <MemberBackInsertionContainer C, typename Value = C::value_type&&> 
-concept_map BackInsertionContainer<C, Value> { 
-  typedef Container<C>::value_type value_type;
+
    
+Some implementations of these functions on POSIX, Windows, and
+presumably on other operating systems, may fail in ways only detectable
+at runtime. Some failures on Windows are due to supporting chipset
+errata and can even occur after successful calls to a clock's now()
+function.
+
    
 
-  void push_back(C& c, value_type&& Value v) { c.push_back(static_cast<value_type&& Value>(v)); } 
-}
-
    
+
    
+These functions are used in cases where exceptions are not appropriate
+or where the specifics of the exception or cause of error need to be
+available to the user. See
+N2828,
+Library Support for hybrid error
+handling (Rev 1), for more specific discussion of use cases. Thus some change in
+the interface of now is required.
+
    
 
-
    ...
    
+
    
+The proposed resolution has been implemented in the Boost version of the
+chrono library. No problems were encountered.
+
    
 
-
    template <MemberInsertionContainer C, typename Value = C::value_type&&> 
-concept_map InsertionContainer<C, Value> { 
-  typedef Container<C>::value_type value_type;
-  Container<C>::iterator insert(C& c, Container<C>::const_iterator i, value_type&& Value v) 
-  { return c.insert(i, static_cast<value_type&& Value>(v)); } 
-}
-
    
+
    [
+Batavia (2009-05):
+]
    
 
+
    
+
    
+We recommend this issue be deferred until the next Committee Draft
+has been issued and the prerequisite paper has been accepted.
+
    
+
    
+Move to Open.
+
    
 
    
 
+
+
    Proposed resolution:
    
 
    
-Change 24.7.1 [back.insert.iterator]:
+Accept the proposed wording of
+N2828,
+Library Support for hybrid error handling (Rev 1).
 
    
 
-
    template <BackInsertionContainer Cont> 
-class back_insert_iterator {
-  ...
-  requires BackInsertionContainer<Cont, const Cont::value_type&>
-           CopyConstructible<Cont::value_type>
-    back_insert_iterator<Cont>& 
-      operator=(const Cont::value_type& value);
-  ...
-
    
-
 
    
-Change 24.7.2.2 [back.insert.iter.op=]:
+Change Clock requirements 20.9.1 [time.clock.req] as indicated:
 
    
 
 
    
-
    requires BackInsertionContainer<Cont, const Cont::value_type&>
-         CopyConstructible<Cont::value_type>
-  back_insert_iterator<Cont>& 
-    operator=(const Cont::value_type& value);
-
    
-
    
--1- Effects: push_back(*container, Cont::value_type(value));
-
    
-
    
-
 
    
-Change 24.7.3 [front.insert.iterator]:
+-2- In Table 55 C1 and C2 denote clock types. t1 and
+t2 are values returned by C1::now() where the call 
+returning t1 happens before (1.10) the call returning t2 and
+both of these calls happen before C1::time_point::max().
+ec denotes an object of type error_code 
+(19.5.2.2 [syserr.errcode.overview]).
 
    
 
-
    template <FrontInsertionContainer Cont> 
-class front_insert_iterator {
-  ...
-  requires FrontInsertionContainer<Cont, const Cont::value_type&>
-           CopyConstructible<Cont::value_type>
-    front_insert_iterator<Cont>& 
-      operator=(const Cont::value_type& value);
-  ...
-
    
+
+
+
+
+
 
-
    
-Change 24.7.4.2 [front.insert.iter.op=]:
-
    
+
+
+
+
+
 
-
    
-
    requires FrontInsertionContainer<Cont, const Cont::value_type&>
-         CopyConstructible<Cont::value_type>
-  front_insert_iterator<Cont>& 
-    operator=(const Cont::value_type& value);
-
    
-
    
--1- Effects: push_front(*container, Cont::value_type(value));
-
    
+
    
+
+
+
+
+
+
+
+
+
+
+
    Table 55 -- Clock requirements
    ExpressionReturn typeOperational semantics
    .........
    C1::now()C1::time_pointReturns a time_point object representing the current point in time.
+
    C1::now(ec)C1::time_pointReturns a time_point object representing the current point in time.
+
    
 
    
 
 
    
-Change 24.7.5 [insert.iterator]:
+Change Class system_clock 20.9.5.1 [time.clock.system] as indicated:
 
    
 
-
    template <InsertionContainer Cont> 
-class insert_iterator {
-  ...
-  requires InsertionContainer<Cont, const Cont::value_type&>
-           CopyConstructible<Cont::value_type>
-    insert_iterator<Cont>& 
-      operator=(const Cont::value_type& value);
-  ...
+
    static time_point now(error_code& ec=throws());
 
    
 
 
    
-Change 24.7.6.2 [insert.iter.op=]:
+Change Class monotonic_clock 20.9.5.2 [time.clock.monotonic] as indicated:
 
    
 
-
    
-
    requires InsertionContainer<Cont, const Cont::value_type&>
-         CopyConstructible<Cont::value_type>
-  insert_iterator<Cont>& 
-    operator=(const Cont::value_type& value);
-
    
-
    
+
    static time_point now(error_code& ec=throws());
+
    
+
 
    
--1- Effects:
+Change Class high_resolution_clock 20.9.5.3 [time.clock.hires] as indicated:
 
    
-
    iter = insert(*container, iter, Cont::value_type(value)); 
-++iter;
+
+
    static time_point now(error_code& ec=throws());
 
    
-
    
-
    
 
 
 
@@ -24655,69 +18412,99 @@ Change 24.7.6.2 [insert.iter.op=]:
 
 
 
    
-
    978. Hashing smart pointers
    
-
    Section: 20.7.17 [unord.hash] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-02-02  Last modified: 2009-05-31
    
-
    View other active issues in [unord.hash].
    
-
    View all other issues in [unord.hash].
    
+
    936. Mutex type overspecified
    
+
    Section: 30.4.1 [thread.mutex.requirements] Status: Open
+ Submitter: Pete Becker Opened: 2008-12-05  Last modified: 2009-03-22
    
+
    View other active issues in [thread.mutex.requirements].
    
+
    View all other issues in [thread.mutex.requirements].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-I don't see an open issue on supporting std::hash for smart pointers
-(unique_ptr and shared_ptr at least).
+30.4.1 [thread.mutex.requirements] describes the requirements for a type to be
+a "Mutex type". A Mutex type can be used as the template argument for
+the Lock type that's passed to condition_variable_any::wait (although
+Lock seems like the wrong name here, since Lock is given a different
+formal meaning in 30.4.3 [thread.lock]) and, although the WD doesn't quite say
+so, as the template argument for lock_guard and unique_lock.
 
    
+
 
    
-It seems reasonable to at least expect support for the smart
-pointers, especially as they support comparison for use in ordered
-associative containers.
+The requirements for a Mutex type include:
 
    
 
-
    [
-Batavia (2009-05):
-]
    
+
      
+
    • 
+m.lock() shall be well-formed and have [described] semantics, including a return type of void.
+
      • 
+
    • 
+m.try_lock() shall be well-formed and have [described] semantics, including a return type of bool.
+
      • 
+
    • 
+m.unlock() shall be well-formed and have [described] semantics, including a return type of void.
+
      • 
+
    
 
-
    
-
    
-Howard points out that the client can always supply a custom hash function.
-
    
 
    
-Alisdair replies that the smart pointer classes are highly likely
-to be frequently used as hash keys.
-
    
-
    
-Bill would prefer to be conservative.
+Also, a Mutex type "shall not be copyable nor movable".
 
    
+
 
    
-Alisdair mentions that this issue may also be viewed as a subissue or
-duplicate of issue 1025.
+The latter requirement seems completely irrelevant, and the three
+requirements on return types are tighter than they need to be. For
+example, there's no reason that lock_guard can't be instantiated with a
+type that's copyable. The rule is, in fact, that lock_guard, etc. won't
+try to copy objects of that type. That's a constraint on locks, not on
+mutexes. Similarly, the requirements for void return types are
+unnecessary; the rule is, in fact, that lock_guard, etc. won't use any
+returned value. And with the return type of bool, the requirement should
+be that the return type is convertible to bool.
 
    
+
+
    [
+Summit:
+]
    
+
+
+
    
 
    
-Move to Open, and recommend the issue be deferred until after the next
-Committee Draft is issued.
+Move to open. Related to conceptualization and should probably be tackled as part of that.
 
    
+
      
+
    • 
+The intention is not only to place a constraint on what types such as
+lock_guard may do with mutex types, but on what any code, including user
+code, may do with mutex types. Thus the constraints as they are apply to
+the mutex types themselves, not the current users of mutex types in the
+standard.
+
      • 
+
    • 
+This is a low priority issue; the wording as it is may be overly
+restrictive but this may not be a real issue.
+
      • 
+
    
 
    
 
 
    [
-2009-05-31 Peter adds:
+Post Summit Anthony adds:
 ]
    
 
 
 
    
-
    
-Howard points out that the client can always supply a custom hash function.
-
    
 
    
-Not entirely true. The client cannot supply the function that hashes the
-address of the control block (the equivalent of the old operator<, now
-proudly carrying the awkward name of 'owner_before'). Only the
-implementation can do that, not necessarily via specializing hash<>, of
-course.
+Section 30.4.1 [thread.mutex.requirements] conflates the
+requirements on a generic Mutex type (including user-supplied mutexes)
+with the requirements placed on the standard-supplied mutex types in an
+attempt to group everything together and save space.
 
    
 
    
-This hash function makes sense in certain situations for shared_ptr
-(when one needs to switch from set/map using ownership ordering to
-unordered_set/map) and is the only hash function that makes sense for
-weak_ptr.
+When applying concepts to chapter 30, I suggest that the concepts
+Lockable and TimedLockable embody the requirements for
+*use* of a mutex type as required by
+unique_lock/lock_guard/condition_variable_any. These should be
+relaxed as Pete describes in the issue. The existing words in 30.4.1 [thread.mutex.requirements] are requirements on all of
+std::mutex, std::timed_mutex,
+std::recursive_mutex and std::recursive_timed_mutex,
+and should be rephrased as such.
 
    
 
    
 
@@ -24732,35 +18519,53 @@ This hash function makes sense in certain situations for shared_ptr
 
 
 
    
-
    979. Bad example
    
-
    Section: 24.5.3 [move.iterators] Status: Tentatively NAD Editorial
- Submitter: Howard Hinnant Opened: 2009-02-03  Last modified: 2009-05-23
    
-
    View all issues with Tentatively NAD Editorial status.
    
+
    939. Problem with std::identity and reference-to-temporaries
    
+
    Section: 20.7.6 [identity.operation] Status: Open
+ Submitter: Alisdair Meredith Opened: 2008-12-11  Last modified: 2009-07-30
    
+
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-24.5.3 [move.iterators] has an incorrect example:
+std::identity takes an argument of type T const &
+and returns a result of T const &.
+
    
+
    
+Unfortunately, this signature will accept a value of type other than T that
+is convertible-to-T, and then return a reference to the dead temporary.  The
+constraint in the concepts version simply protects against returning
+reference-to-void.
+
    
+
    
+Solutions:
 
    
-
 
    
 
    
--2- [Example:
+i/  Return-by-value, potentially slicing bases and rejecting non-copyable
+types
+
    
+
    
+ii/ Provide an additional overload:
+
    
+
    template< typename T >
+template operator( U & ) = delete;
+
    
+
    
+This seems closer on intent, but moves beyond the original motivation for
+the operator, which is compatibility with existing (non-standard)
+implementations.
+
    
+
    
+iii/ Remove the operator() overload.  This restores the original definition
+of the identity, although now effectively a type_trait rather than part of
+the perfect forwarding protocol.
 
    
-
-
    set<string> s; 
-// populate the set s 
-vector<string> v1(s.begin(), s.end());          // copies strings into v1 
-vector<string> v2(make_move_iterator(s.begin()), 
-                  make_move_iterator(s.end())); // moves strings into v2
-
    
-
 
    
--- end example]
+iv/ Remove std::identity completely; its original reason to exist is
+replaced with the IdentityOf concept.
 
    
 
    
-
 
    
-One can not move from a set because the iterators return const
-references.
+My own preference is somewhere between (ii) and (iii) - although I stumbled
+over the issue with a specific application hoping for resolution (i)!
 
    
 
 
    [
@@ -24768,179 +18573,131 @@ Batavia (2009-05):
 ]
    
 
 
    
-We agree with the proposed resolution. Move to NAD Editorial.
-
    
-
-
-
-
    Proposed resolution:
    
-
    
-Change 24.5.3 [move.iterators]/2:
-
    
-
-
    
 
    
--2- [Example:
+We dislike options i and iii, and option ii seems like overkill.
+If we remove it (option iv), implementers can still provide it under a
+different name.
 
    
-
-
    setlist<string> s; 
-// populate the setlist s 
-vector<string> v1(s.begin(), s.end());          // copies strings into v1 
-vector<string> v2(make_move_iterator(s.begin()), 
-                  make_move_iterator(s.end())); // moves strings into v2
-
    
-
 
    
--- end example]
+Move to Open pending wording (from Alisdair) for option iv.
 
    
 
    
 
+
    [
+2009-05-23 Alisdair provided wording for option iv.
+]
    
 
 
-
-
-
    
-
    981. Unordered container requirements should add  initializer_list support
    
-
    Section: 23.2.5 [unord.req] Status: Tentatively Ready
- Submitter: Daniel Krügler Opened: 2009-02-08  Last modified: 2009-05-23
    
-
    View other active issues in [unord.req].
    
-
    View all other issues in [unord.req].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
-
    
-Refering to
-N2800
-all container requirements tables (including those for
-associative containers) provide useful member function overloads
-accepting std::initializer_list as argument, the only exception is
-Table 87. There seems to be no reason for not providing them, because 23.5 [unord]
-is already initializer_list-aware. For the sake of 
-library interface consistency and user-expectations corresponding 
-overloads should be added to the table requirements of unordered 
-containers as well.
-
    
-
 
    [
-Batavia (2009-05):
+2009-07-20 Alisdair adds:
 ]
    
 
+
 
    
 
    
-We agree with the proposed resolution.
+I'm not sure why this issue was not discussed at Frankfurt (or I missed
+the discussion) but the rationale is now fundamentally flawed.  With the
+removal of concepts, std::identity again becomes an important library
+type so we cannot simply remove it.
 
    
 
    
-Move to Tentatively Ready.
+At that point, we need to pick one of the other suggested resolutions,
+but have no guidance at the moment.
 
    
 
    
 
+
    [
+2009-07-20 Howard adds:
+]
    
 
-
    Proposed resolution:
    
 
+
    
 
    
-In 23.2.5 [unord.req]/9 insert:
+I believe the rationale for not addressing this issue in Frankfurt was that it did
+not address a national body comment.
 
    
-
-
    
-... [q1, q2) is a valid range in a, il
-designates an object of type initializer_list<value_type>, t is a value of type
-X::value_type, ...
-
    
-
 
    
-In 23.2.5 [unord.req], Table 87 insert:
+I also believe that removal of identity is still a practical option as
+my latest reformulation of forward, which is due to comments suggested
+at Summit, no longer uses identity. :-)
 
    
 
-
    
-
-
-
-
-
-
-
-
-
- 
- 
-
-
-
-
-
-
-
-
-
- 
- 
-
-
-
-
-
-
-
-
-
- 
- 
-
-
-
    Table 87 - Unordered associative container requirements (in addition to container)
    Expression Return type Assertion/note
    pre-/post-condition    		 Complexity
    X(i, j)
    X a(i, j)    		 X ... ...
    X(il) XSame as X(il.begin(), il.end()).Same as X(il.begin(), il.end()).
    ... ... ... ...
    a = b X ... ...
    a = il X&a = X(il); return *this;Same as a = X(il).
    ... ... ... ...
    a.insert(i, j) void ... ...
    a.insert(il) voidSame as a.insert(il.begin(), il.end()).Same as a.insert(il.begin(), il.end()).
    
-
    
-
+
    template <class T, class U,
+    class = typename enable_if
+            <
+                !is_lvalue_reference<T>::value || 
+                 is_lvalue_reference<T>::value &&
+                 is_lvalue_reference<U>::value
+            >::type,
+    class = typename enable_if
+            <
+                is_same<typename remove_all<T>::type,
+                        typename remove_all<U>::type>::value
+            >::type>
+inline
+T&&
+forward(U&& t)
+{
+    return static_cast<T&&>(t);
 
+}
+
    
 
+
    [
+The above code assumes acceptance of 1120 for the definition of
+remove_all.  This is just to make the syntax a little more palatable.
+Without this trait the above is still very implementable.
+]
    
 
 
+
    
 
-
    
-
    982. Wrong complexity for initializer_list assignment in  Table 85
    
-
    Section: 23.2.4 [associative.reqmts] Status: Tentatively Ready
- Submitter: Daniel Krügler Opened: 2009-02-08  Last modified: 2009-05-23
    
-
    View other active issues in [associative.reqmts].
    
-
    View all other issues in [associative.reqmts].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
 
    
-According to
-N2800,
-the associative container requirements table 85 says
-    that assigning an initializer_list to such a container is of
-    constant complexity, which is obviously wrong.
+Paper with rationale is on the way ... really, I promise this time! ;-)
 
    
+
    
 
 
    [
-Batavia (2009-05):
+2009-07-30 Daniel adds:  See 823 for an alternative resolution.
 ]
    
 
-
    
-
    
-We agree with the proposed resolution.
-
    
+
+
+
    Proposed resolution:
    
 
    
-Move to Tentatively Ready.
+Strike 20.2.1 [concept.transform] p3:
 
    
+
+
    
+-4- Note: concept form of the identity type metafunction (20.7.6).
 
    
 
+
    
+Strike from 20.7 [function.objects] p2:
+
    
 
-
    Proposed resolution:
    
+
    // 20.7.6, identity operation:
+template <IdentityOf T> struct identity;
+
    
 
 
    
-In 23.2.4 [associative.reqmts], Table 85 change:
+Remove 20.7.6 [identity.operation] (whole subclause):
 
    
 
 
    
-
-
-
-
-
-
- 
-
-
-
    Table 85 - Associative container requirements (in addition to container)
    Expression Return type Assertion/note
    pre-/post-condition    		 Complexity
    a = il X& a = X(il);
    return *this;    		constantSame as a = X(il).
    
+
    template <IdentityOf T> struct identity {
+  typedef T type;
+
+  requires ReferentType<T>
+     const T& operator()(const T& x) const;
+};
+
+requires ReferentType<T>
+  const T& operator()(const T& x) const;
+
    
+
    
+-1-  Returns: x
+
    
 
    
 
 
@@ -24949,556 +18706,682 @@ In 23.2.4 [associative.reqmts], Table 85 change:
 
 
 
    
-
    983. unique_ptr reference deleters should not be moved from
    
-
    Section: 20.8.12.2 [unique.ptr.single] Status: Review
- Submitter: Howard Hinnant Opened: 2009-02-10  Last modified: 2009-05-23
    
-
    View other active issues in [unique.ptr.single].
    
-
    View all other issues in [unique.ptr.single].
    
-
    View all issues with Review status.
    
+
    940. std::distance
    
+
    Section: 24.4 [iterator.operations] Status: Open
+ Submitter: Thomas Opened: 2008-12-14  Last modified: 2009-07-18
    
+
    View other active issues in [iterator.operations].
    
+
    View all other issues in [iterator.operations].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
-
    
-Dave brought to my attention that when a unique_ptr has a non-const reference
-type deleter, move constructing from it, even when the unique_ptr containing
-the reference is an rvalue, could have surprising results:
-
    
-
-
    D d(some-state);
-unique_ptr<A, D&> p(new A, d);
-unique_ptr<A, D> p2 = std::move(p);
-// has d's state changed here?
-
    
 
-
    
-I agree with him.  It is the unique_ptr that is the rvalue, not the
-deleter.  When the deleter is a reference type, the unique_ptr should
-respect the "lvalueness" of the deleter.
-
    
+
    Addresses UK 270
    
 
 
    
-Thanks Dave.
+Regarding the std::distance - function, 24.4 [iterator.operations]
+/ 4 says:
 
    
-
-
    [
-Batavia (2009-05):
-]
    
-
 
    
-Seems correct, but complicated enough that we recommend moving to Review.
+Returns the
+number of increments or decrements needed to get from first to last.
 
    
-
-
-
    Proposed resolution:
    
 
    
-Change 20.8.12.2.1 [unique.ptr.single.ctor], p20-21
+This sentence is completely silent about the sign of the return value.
+24.4 [iterator.operations] / 1 gives more information about the
+underlying operations, but
+again no inferences about the sign can be made.
+Strictly speaking, that is taking that sentence literally, I think this
+sentence even implies a positive return value in all cases, as the
+number of increments or decrements is clearly a ratio scale variable,
+with a natural zero bound.
 
    
-
-
    
-
    template <class U, class E> unique_ptr(unique_ptr<U, E>&& u);
-
    
-
-
    
-
 
    
--20- Requires: If D E is not a reference type,
-construction of the deleter D from an rvalue of type E
-shall be well formed and shall not throw an exception.
-
-Otherwise E is a reference type and construction of the deleter
-D from an lvalue of type E shall be well formed and
-shall not throw an exception.
-
-If D is
-a reference type, then E shall be the same type as D
-(diagnostic required). unique_ptr<U, E>::pointer shall be
-implicitly convertible to pointer. [Note: These
-requirements imply that T and U are complete types.
--- end note]
+Practically speaking, my implementations did what common sense and
+knowledge based on pointer arithmetic forecasts, namely a positive sign
+for increments (that is, going from first to last by operator++), and a
+negative sign for decrements (going from first to last by operator--).
 
    
-
 
    
--21- Effects: Constructs a unique_ptr which owns the
-pointer which u owns (if any). If the deleter
-E is not a reference type, it this
-deleter is move constructed from u's deleter, otherwise
-the reference this deleter is copy constructed
-from u.'s deleter. After the construction, u no longer
-owns a pointer. [Note: The deleter constructor can be implemented
-with std::forward<DE>. -- end
-note]
+Here are my two questions:
 
    
-
-
    
-
    
-
 
    
-Change 20.8.12.2.3 [unique.ptr.single.asgn], p1-3
+First, is that paragraph supposed to be interpreted in the way what I
+called 'common sense', that is negative sign for decrements ? I am
+fairly sure that's the supposed behavior, but a double-check here in
+this group can't hurt.
 
    
-
-
    
-
    unique_ptr& operator=(unique_ptr&& u);
-
    
-
    
-
 
    
--1- Requires: If the deleter D is not a reference type,
-Aassignment of the deleter D from an rvalue D shall not throw an exception.
-
-Otherwise the deleter D is a reference type,
-and assignment of the deleter D from an lvalue D shall not throw an exception.
+Second, is the present wording (2003 standard version - no idea about
+the draft for the upcoming standard) worth an edit to make it a bit more
+sensible, to mention the sign of the return value explicitly ?
 
    
 
+
    [
+Daniel adds:
+]
    
+
+
+
    
 
    
--2- Effects: reset(u.release()) followed by
-an move assignment from u's deleter to this deleter
-std::forward<D>(u.get_deleter()).
+My first thought was that resolution 204 would already cover the
+issue report, but it seems that current normative wording is in
+contradiction to that resolution:
 
    
 
 
    
--3- Postconditions: This unique_ptr now owns the pointer
-which u owned, and u no longer owns it. [Note: If
-D is a reference type, then the referenced lvalue deleters are
-move assigned. -- end note]
+Referring to
+N2798,
+24.4 [iterator.operations]/ p.4 says:
 
    
-
    
+
+
    
+Effects: Returns the number of increments or decrements needed to get
+from first to last.
 
    
 
 
    
-Change 20.8.12.2.3 [unique.ptr.single.asgn], p6-7
+IMO the part " or decrements" is in contradiction to p. 5 which says
 
    
 
 
    
-
    template <class U, class E> unique_ptr& operator=(unique_ptr<U, E>&& u);
-
    
+Requires: last shall be reachable from first.
+
    
+
+
    
+because "reachable" is defined in 24.2 [iterator.concepts]/7 as
+
    
+
 
    
+An iterator j is called reachable from an iterator i if and only if
+there is a finite
+sequence of applications of the expression ++i that makes i == j.[..]
+
    
 
 
    
-Requires: If the deleter E is not a reference type,
-Aassignment of the deleter D from an rvalue
-DE shall not throw an exception.
-
-Otherwise the deleter E is a reference type,
-and assignment of the deleter D from an lvalue E shall not throw an exception.
-unique_ptr<U, E>::pointer shall be implicitly convertible to pointer.
-[Note: These requirements imply that T and U>
-are complete types. -- end note]
+Here is wording that would be consistent with this definition of "reachable":
 
    
 
 
    
-Effects: reset(u.release()) followed by
-an move assignment from u's deleter to this deleter
-std::forward<E>(u.get_deleter()).
-If either
-D or E is a reference type, then the referenced lvalue
-deleter participates in the move assignment.
+Change 24.4 [iterator.operations] p4 as follows:
 
    
 
+
    
+Effects: Returns the number of increments or decrements
+needed to get from first to last.
 
    
+
 
    
 
+
    
+Thomas adds more discussion and an alternative view point
+here.
+
    
 
+
    [
+Summit:
+]
    
 
 
+
    
+The proposed wording below was verbally agreed to.  Howard provided.
+
    
 
+
    [
+Batavia (2009-05):
+]
    
 
-
    
-
    984. Does <cinttypes> have macro guards?
    
-
    Section: 27.9.2 [c.files] Status: Tentatively Ready
- Submitter: Howard Hinnant Opened: 2009-02-12  Last modified: 2009-05-23
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
+
    
+
    
+Pete reports that a recent similar change has been made
+for the advance() function.
+
    
 
    
-The C standard says about <inttypes.h>:
+We agree with the proposed resolution.
+Move to Tentatively Ready.
 
    
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
 
 
    
-C++ implementations should define these macros only when __STDC_FORMAT_MACROSis defined 
-before <inttypes.h> is included.
+Moved from Tentatively Ready to Open only because the wording needs to be
+tweaked for concepts removal.
 
    
 
-
    
-The C standard has a similar note about <stdint.h>.  For <cstdint>
-we adopted a "thanks but no thanks" policy and documented that fact in
-18.4.1 [cstdint.syn]:
-
    
+
    [
+2009-07 Frankfurt:
+]
    
+
 
 
    
-... [Note: The macros defined by <stdint> are
-provided unconditionally. In particular, the symbols
-__STDC_LIMIT_MACROS and __STDC_CONSTANT_MACROS
-(mentioned in C99 footnotes 219, 220, and 222) play no role in C++.
--- end note]
+Leave Open pending arrival of a post-Concepts WD.
 
    
 
+
+
+
    Proposed resolution:
    
 
    
-I recommend we put a similar note in 27.9.2 [c.files] regarding <cinttypes>.
+Change 24.4 [iterator.operations]:
 
    
 
-
    [
-Batavia (2009-05):
-]
    
+
    
+
    template <InputIterator Iter>
+  Iter::difference_type
+  distance(Iter first, Iter last);
+template <RandomAccessIterator Iter>
+  Iter::difference_type distance(Iter first, Iter last);
+
    
 
 
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
+
    
+-4- Effects: Returns the number of increments or decrements
+needed to get from first to last.
+
    
+
    
+-5- Requires: last shall be reachable from first.
+
    
 
    
 
+
    template <RandomAccessIterator Iter>
+  Iter::difference_type distance(Iter first, Iter last);
+
    
 
-
    Proposed resolution:
    
+
    
+
    
+-6- Effects: Returns the number of increments or decrements
+needed to get from first to last.
+
    
 
    
-Add to 27.9.2 [c.files]:
+-7- Requires: last shall be reachable from first
+or first shall be reachable from last.
 
    
+
    
+
 
-
    
-Table 112 describes header <cinttypes>.
-
-[Note: The macros defined by <cintypes> are
-provided unconditionally. In particular, the symbol
-__STDC_FORMAT_MACROS
-(mentioned in C99 footnote 182) plays no role in C++.
--- end note]
-
 
    
 
 
 
 
 
+
 
    
-
    985. Allowing throwing move
    
-
    Section: 23.2.1 [container.requirements.general] Status: Open
- Submitter: Rani Sharoni Opened: 2009-02-12  Last modified: 2009-05-23
    
-
    View other active issues in [container.requirements.general].
    
-
    View all other issues in [container.requirements.general].
    
+
    944. atomic<bool> derive from atomic_bool?
    
+
    Section: 29.5.3 [atomics.types.generic] Status: Open
+ Submitter: Holger Grund Opened: 2008-12-19  Last modified: 2009-03-22
    
+
    View all other issues in [atomics.types.generic].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-Introduction
-
    
-
-
    This proposal is meant to resolve potential regression of the
-N2800
-draft, see
-next section, and to relax the requirements for containers of types with
-throwing move constructors.
    
-
-
    The basic problem is that some containers operations, like push_back,
-have a strong exception safety
-guarantee (i.e. no side effects upon exception) that are not achievable when
-throwing move constructors are used since there is no way to guarantee revert
-after partial move. For such operations the implementation can at most provide
-the basic guarantee (i.e. valid but unpredictable) as it does with multi
-copying operations (e.g. range insert).
    
-
-
    For example, vector<T>::push_back() (where T has a move
-constructor) might resize the vector and move the objects to the new underlying
-buffer. If move constructor throws it might
-not be possible to recover the throwing object or to move the old objects back to
-the original buffer.
    
-
-
    The current draft is explicit by disallowing throwing move
-for some operations (e.g. vector<>::reserve) and not clear about other
-operations mentioned in 23.2.1 [container.requirements.general]/10
-(e.g. single element insert): it guarantees strong exception
-safety without explicitly disallowing a throwing move constructor.
+I think it's fairly obvious that atomic<bool> is supposed to be derived
+from atomic_bool (and otherwise follow the atomic<integral> interface),
+though I think the current wording doesn't support this. I raised this
+point along with atomic<floating-point> privately with Herb and I seem
+to recall it came up in the resulting discussion on this list. However,
+I don't see anything on the current libs issue list mentioning this
+problem.
 
    
 
 
    
-Regression
+29.5.3 [atomics.types.generic]/3 reads
 
    
 
-
    This section only refers to cases in which the contained object
-is by itself a standard container.
    
+
    
+There are full specializations over the integral types on the atomic
+class template. For each integral type integral in the second column of
+table 121 or table 122, the specialization atomic<integral> shall be
+publicly derived from the corresponding atomic integral type in the
+first column of the table. These specializations shall have trivial
+default constructors and trivial destructors.
+
    
 
-
    Move constructors of standard containers are allowed to throw and therefore
-existing operations are broken, compared with C++03, due to move optimization.
-(In fact existing implementations like Dinkumware are actually throwing).
    
+
    
+Table 121 does not include (atomic_bool, bool),
+so that this should probably be mentioned explicitly in the quoted paragraph.
+
    
 
-
    For example, vector< list<int> >::reserve yields
-undefined behavior since list<int>'s move constructor is allowed to throw.
-On the other hand, the same operation has strong exception safety guarantee in
-C++03.
    
+
    [
+Summit:
+]
    
 
-
    There are few options to solve this regression:
    
 
-
      
-
    1. 
-Disallow throwing move and throwing default constructor
-
      2. 
+
      
+Move to open. Lawrence will draft a proposed resolution. Also, ask
+Howard to fix the title.
+
      
 
-
    2. 
-Disallow throwing move but disallowing usage after move
-
      3. 
+
      [
+Post Summit Anthony provided proposed wording.
+]
      
 
-
    3. 
-Special casing
-
      4. 
 
-
    4. 
-Disallow throwing move and making it optional
-
      5. 
 
-
    
+
    Proposed resolution:
    
+
    
+Replace paragraph 3 in 29.5.3 [atomics.types.generic] with
+
    
 
-
    Option 1 is suggested by proposal
-N2815
-but it might not be applicable for existing implementations for which
-containers default constructors are throwing.
    
+
    
+-3- There are full specializations over the integral types on the atomic
+class template. For each integral type integral in the second column of
+table 121 or table 122, the specialization atomic<integral> shall be
+publicly derived from the corresponding atomic integral type in the first
+column of the table.
+In addition, the specialization atomic<bool>
+shall be publicly derived from atomic_bool.
+These specializations shall have trivial default
+constructors and trivial destructors.
+
    
 
-
    Option 2 limits the usage significantly and it's error prone
-by allowing zombie objects that are nothing but destructible (e.g. no clear()
-is allowed after move). It also potentially complicates the implementation by
-introducing special state.
    
 
-
    Option 3 is possible, for example, using default
-construction and swap instead of move for standard containers case. The
-implementation is also free to provide special hidden operation for non
-throwing move without forcing the user the cope with the limitation of option-2
-when using the public move.
    
 
-
    Option 4 impact the efficiency in all use cases due to rare throwing move.
    
 
-
    The proposed wording will imply option 1 or 3 though option 2 is also
-achievable using more wording. I personally oppose to option 2 that has impact
-on usability.
    
 
+
    
+
    947. duration arithmetic: contradictory requirements
    
+
    Section: 20.9.3.5 [time.duration.nonmember] Status: Open
+ Submitter: Pete Becker Opened: 2008-12-20  Last modified: 2009-07-27
    
+
    View all other issues in [time.duration.nonmember].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
 
    
-Relaxation for user types
+In 20.9.3.5 [time.duration.nonmember], paragraph 8 says that calling
+dur / rep
+when rep is an instantiation of duration requires a diagnostic.
+That's followed by an operator/ that takes two durations.
+So dur1 / dur2 is legal under the second version,
+but requires a diagnostic under the first.
 
    
 
-
    Disallowing throwing move constructors in general seems very restrictive
-since, for example, common implementation of move will be default construction
-+ swap so move will throw if the
-default constructor will throw. This is currently the case with the Dinkumware
-implementation of node based containers (e.g. std::list)
-though this section doesn't refer to standard types.
    
+
    [
+Howard adds:
+]
    
 
-
    For throwing move constructors it seem that the implementation should have
-no problems to provide the basic guarantee instead of the strong one. It's
-better to allow throwing move constructors with basic guarantee than to
-disallow it silently (compile and run), via undefined behavior.
    
 
-
    There might still be cases in which the relaxation will break existing generic
-code that assumes the strong guarantee but it's broken either way given a
-throwing move constructor since this is not a preserving optimization. 
    
+
    
+Please see the thread starting with c++std-lib-22980 for more information.
+
    
 
 
    [
 Batavia (2009-05):
 ]
    
 
 
    
+Move to Open, pending proposed wording (and preferably an implementation).
+
    
+
+
    [
+2009-07-27 Howard adds:
+]
    
+
+
+
    
 
    
-Bjarne comments (referring to his draft paper):
-"I believe that my suggestion simply solves that.
-Thus, we don't need a throwing move."
+I've addressed this issue under the proposed wording for 1177 which
+cleans up several places under 20.9.3 [time.duration] which used the
+phrase "diagnostic required".
 
    
 
    
-Move to Open and recommend it be deferred until after the next
-Committee Draft is issued.
+For clarity's sake, here is an example implementation of the constrained operator/:
 
    
-
    
 
+
    template <class _Duration, class _Rep, bool = __is_duration<_Rep>::value>
+struct __duration_divide_result
+{
+};
 
-
    Proposed resolution:
    
+template <class _Duration, class _Rep2,
+    bool = is_convertible<_Rep2,
+                          typename common_type<typename _Duration::rep, _Rep2>::type>::value>
+struct __duration_divide_imp
+{
+};
+
+template <class _Rep1, class _Period, class _Rep2>
+struct __duration_divide_imp<duration<_Rep1, _Period>, _Rep2, true>
+{
+    typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period> type;
+};
+
+template <class _Rep1, class _Period, class _Rep2>
+struct __duration_divide_result<duration<_Rep1, _Period>, _Rep2, false>
+    : __duration_divide_imp<duration<_Rep1, _Period>, _Rep2>
+{
+};
+
+template <class _Rep1, class _Period, class _Rep2>
+inline
+typename __duration_divide_result<duration<_Rep1, _Period>, _Rep2>::type
+operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
+{
+    typedef typename common_type<_Rep1, _Rep2>::type _Cr;
+    duration<_Cr, _Period> __r = __d;
+    __r /= static_cast<_Cr>(__s);
+    return __r;
+}
+
    
 
 
    
-23.2.1 [container.requirements.general]  paragraph 10 add footnote:
+__duration_divide_result is basically a custom-built enable_if
+that will contain type only if Rep2 is not a duration
+and if Rep2 is implicitly convertible to
+common_type<typename Duration::rep, Rep2>::type. __is_duration
+is simply a private trait that answers false, but is specialized for
+duration to answer true.
 
    
 
-
    
 
    
--10- Unless otherwise specified (see 23.1.4.1, 23.1.5.1, 23.2.2.3, and
-23.2.6.4) all container types defined in this Clause meet the following
-additional requirements:
+The constrained operator% works identically.
 
    
-
      
-
    • ...
      • 
-
    
+
    
 
+
+
    Proposed resolution:
    
 
    
-[Note: for compatibility with C++
-2003, when "no effect" is required, standard containers should not use the
-value_type's throwing move constructor when the contained object is by itself a
-standard container. -- end note]
 
    
 
-
    
 
-
    23.2.5.1 [unord.req.except] change paragraph 2 to say: 
    
 
-
    
+
+
+
    
+
    950. unique_ptr converting ctor shouldn't accept array form
    
+
    Section: 20.8.9.2.1 [unique.ptr.single.ctor] Status: Review
+ Submitter: Howard Hinnant Opened: 2009-01-07  Last modified: 2009-08-01
    
+
    View other active issues in [unique.ptr.single.ctor].
    
+
    View all other issues in [unique.ptr.single.ctor].
    
+
    View all issues with Review status.
    
+
    Discussion:
    
 
    
--2- For unordered associative containers, if an exception is
-thrown by any operation other than the container's hash function from within an
-insert() function inserting a single element, the insert()
-function has no effect unless the exception is thrown by the contained
-object move constructor.
+unique_ptr's of array type should not convert to
+unique_ptr's which do not have an array type.
 
    
 
-
    
--4- For unordered associative containers, if an exception is
-thrown from within a rehash() function other than by the container's hash
-function or comparison function, the rehash() function has no effect
-unless the exception is thrown by the contained
-object move constructor.
    
+
    struct Deleter
+{
+   void operator()(void*) {}
+};
+
+int main()
+{
+   unique_ptr<int[], Deleter> s;
+   unique_ptr<int, Deleter> s2(std::move(s));  // should not compile
+}
+
    
+
+
    [
+Post Summit:
+]
    
 
-
    
 
+
    
 
    
-23.3.2.3 [deque.modifiers] change paragraph 2 to say:
+Walter: Does the "diagnostic required" apply to both arms of the "and"?
+
    
+
    
+Tom Plum: suggest to break into several sentences
+
    
+
    
+Walter: suggest "comma" before the "and" in both places
+
    
+
    
+Recommend Review.
 
    
+
    
+
+
    [
+Batavia (2009-05):
+]
    
 
 
    
--2- Remarks: If an exception is thrown other than by
-the copy constructor, move constructor
-or assignment operator of T
-there are no effects.
-If an exception is thrown by push_back() or emplace_back()
-function, that function has no effects unless the exception is thrown by
-the move constructor of T.
+The post-Summit comments have been applied to the proposed resolution.
+We now agree with the proposed resolution.
+Move to Tentatively Ready.
 
    
 
-
    
-23.3.2.3 [deque.modifiers] change paragraph 6 to say:
-
    
+
    [
+2009-07 Frankfurt
+]
    
+
 
 
    
--6- Throws: Nothing unless an exception is thrown by the copy
-constructor, move constructor or assignment operator of T.
+Moved from Tentatively Ready to Open only because the wording needs to be
+improved for enable_if type constraining, possibly following Robert's
+formula.
 
    
 
+
    [
+2009-08-01 Howard updates wording and sets to Review.
+]
    
+
+
+
+
+
    Proposed resolution:
    
 
    
-23.3.6.2 [vector.capacity] remove paragraph 2
+Change 20.8.9.2.1 [unique.ptr.single.ctor]:
 
    
 
 
    
--2- Requires: If value_type has a move constructor,
-that constructor shall not throw any exceptions.
+
    template <class U, class E> unique_ptr(unique_ptr<U, E>&& u);
+
    
+
    
+
    
+-20- Requires: If D is not a reference type,
+construction of the deleter D from an rvalue of type E
+shall be well formed and shall not throw an exception. If D is
+a reference type, then E shall be the same type as D
+(diagnostic required). unique_ptr<U, E>::pointer shall be
+implicitly convertible to pointer. [Note: These requirements
+imply that T and U are complete types. — end note]
+
    
+
+
    
+Remarks: If D is
+a reference type, then E shall be the same type as D, else this
+constructor shall not participate in overload resolution. unique_ptr<U, E>::pointer shall be
+implicitly convertible to pointer, else this
+constructor shall not participate in overload resolution. U shall not be
+an array type, else this
+constructor shall not participate in overload resolution. [Note: These requirements
+imply that T and U are complete types. — end note]
+
    
+
+
    
 
    
 
 
    
-23.3.6.2 [vector.capacity] paragraph 3 change to say:
+Change 20.8.9.2.3 [unique.ptr.single.asgn]:
 
    
 
 
    
--3- Effects: A directive that informs a vector
-of a planned change in size, so
-that it can manage the storage allocation accordingly. After reserve(),
-capacity() is greater or equal to the argument of reserve
-if reallocation happens; and equal
-to the previous value of capacity()
-otherwise. Reallocation happens at this point if and only if the current
-capacity is less than the argument of reserve().
-If an exception is thrown, there are no effects
-unless the exception is thrown by the contained object move constructor.
+
    template <class U, class E> unique_ptr& operator=(unique_ptr<U, E>&& u);
+
    
+
    
+
    
+-6- Requires: Assignment of the deleter D from an rvalue
+D shall not throw an exception. unique_ptr<U,
+E>::pointer shall be implicitly convertible to pointer.
+[Note: These requirements imply that T and U
+are complete types. — end note]
+
    
+
+
    
+Remarks: unique_ptr<U,
+E>::pointer shall be implicitly convertible to pointer, else this
+operator shall not participate in overload resolution.
+U shall not be an array type, else this
+operator shall not participate in overload resolution.
+[Note: These requirements imply that T and U
+are complete types. — end note]
+
    
+
 
    
+
    
+
+
+
+
+
+
+
    
+
    951. Various threading bugs #1
    
+
    Section: 20.9.2.1 [time.traits.is_fp] Status: Open
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-08-01
    
+
    View all issues with Open status.
    
+
    Discussion:
    
 
 
    
-23.3.6.2 [vector.capacity] paragraph 12 change to say:
+Related to 953.
+
    
+
+
    
+20.9.2.1 [time.traits.is_fp] says that the type Rep "is
+assumed to be ... a class emulating an integral type." What are the
+requirements for such a type?
 
    
+
    [
+2009-05-10 Howard adds:
+]
    
+
 
 
    
--12- Requires: If value_type has a move constructor,
-that constructor shall not throw any exceptions.
-If an exception is thrown, there are no effects unless the exception is thrown by
-the contained object move constructor.
+IntegralLike.
 
    
 
+
    [
+Batavia (2009-05):
+]
    
+
+
    
 
    
-23.3.6.4 [vector.modifiers] change paragraph 1 to say:
+As with issue 953,
+we recommend this issue be addressed in the context of providing concepts for the entire thread header.
+
    
+
    
+We look forward to proposed wording.
 
    
+
    
+Move to Open.
+
    
+
    
+
+
    [
+2009-08-01 Howard adds:
+]
    
+
 
 
    
--1- Requires: If value_type has a move constructor,
-that constructor shall not throw any exceptions.
-Remarks: If an exception is thrown by push_back()
-or emplace_back() function, that function has no effect unless the
-exception is thrown by the move constructor of T.
-
    
+
    
+I have surveyed all clauses of 20.9.2.2 [time.traits.duration_values],
+20.9.2.3 [time.traits.specializations] and 20.9.3 [time.duration].
+I can not find any clause which involves the use of a duration::rep type
+where the requirements on the rep type are not clearly spelled out.
+These requirements were carefully crafted to allow any arithmetic type, or
+any user-defined type emulating an arithmetic type.
+
    
 
 
    
-23.3.6.4 [vector.modifiers] change paragraph 2 to say:
+Indeed, treat_as_floating_point
+becomes completely superfluous if duration::rep can never be a class type.
 
    
 
-
    
--2- Remarks: Causes reallocation if the new size is greater than
-the old capacity. If no reallocation happens, all the iterators and
-references before the insertion point remain valid. If an exception is
-thrown other than by the copy constructor, move constructor
-or assignment operator of T or by any InputIterator
-operation there are no effects.
-
    
+
    
+There will be some Rep types which will not meet the requirements of
+every duration operation.  This is no different than the fact
+that vector<T> can easily be used for types T which are
+not DefaultConstructible, even though some members of vector<T>
+require T to be DefaultConstructible.  This is why the requirements
+on Rep are specified for each operation individually.
+
    
 
 
    
-23.3.6.4 [vector.modifiers] change paragraph 6 to say:
+In 20.9.2.1 [time.traits.is_fp] p1:
 
    
 
+
    template <class Rep> struct treat_as_floating_point 
+  : is_floating_point<Rep> { };
+
    
+
 
    
--6- Throws: Nothing unless an exception is thrown by the copy
-constructor, move constructor or assignment operator of T.
+The duration template uses the treat_as_floating_point trait to help
+determine if a duration object can be converted to another duration
+with a different tick period. If treat_as_floating_point<Rep>::value is
+true, then Rep is a floating-point type and implicit conversions are
+allowed among durations. Otherwise, the implicit convertibility depends
+on the tick periods of the durations. If Rep is a class type which
+emulates a floating-point type, the author of Rep can specialize
+treat_as_floating_point so that duration will treat this Rep as if it
+were a floating-point type. Otherwise Rep is assumed to be an integral
+type or a class emulating an integral type.
+
    
 
    
 
+
    
+The phrases "a class type which emulates a floating-point type" and
+"a class emulating an integral type" are clarifying phrases which refer to
+the summation of all the requirements on the Rep type specified in
+detail elsewhere (and should not be repeated here).
+
    
 
+
    
+This specification has been implemented, now multiple times, and the experience
+has been favorable.  The current specification clearly specifies the requirements
+at each point of use (though I'd be happy to fix any place I may have missed,
+but none has been pointed out).
+
    
 
+
    
+I am amenable to improved wording of this paragraph (and any others), but to not have any
+suggestions for improved wording at this time.  I am strongly opposed to
+changes which would significantly alter the semantics of the
+specification under 20.9 [time] without firmly grounded and
+documented rationale, example implementation, testing, and user
+experience which relates a positive experience.
+
    
 
-
-
-
    
-
    986. Generic try_lock contradiction
    
-
    Section: 30.4.4 [thread.lock.algorithm] Status: Tentatively Ready
- Submitter: Chris Fairles Opened: 2009-02-14  Last modified: 2009-05-23
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
 
    
-In 30.4.4 [thread.lock.algorithm], the generic try_lock effects (p2) say that a failed
-try_lock is when it either returns false or throws an exception. In
-the event a call to try_lock does fail, by either returning false or
-throwing an exception, it states that unlock shall be called for all
-prior arguments. Then the returns clause (p3) goes on to state
-in a note that after returning, either all locks are locked or none
-will be. So what happens if multiple locks fail on try_lock?
+I recommend NAD unless someone wants to produce some clarifying wording.
 
    
+
    
+
 
+
    Proposed resolution:
    
 
    
-Example:
 
    
 
-
    #include <mutex>
 
-int main() {
- std::mutex m0, m1, m2;
- std::unique_lock<std::mutex> l0(m0, std::defer_lock);
- std::unique_lock<std::mutex> l1(m1); //throws on try_lock
- std::unique_lock<std::mutex> l2(m2); //throws on try_lock
 
- int result = std::try_lock(l0, l1, l2);
 
- assert( !l0.owns_lock() );
- assert( l1.owns_lock() ); //??
- assert( l2.owns_lock() ); //??
-}
-
    
+
+
    
+
    953. Various threading bugs #3
    
+
    Section: 20.9.1 [time.clock.req] Status: Open
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-08-01
    
+
    View other active issues in [time.clock.req].
    
+
    View all other issues in [time.clock.req].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
 
 
    
-The first lock's try_lock succeeded but, being a prior argument to a
-lock whose try_lock failed, it gets unlocked as per the effects clause
-of 30.4.4 [thread.lock.algorithm]. However, 2 locks remain locked in this case but the return
-clause states that either all arguments shall be locked or none will
-be. This seems to be a contradiction unless the intent is for
-implementations to make an effort to unlock not only prior arguments,
-but the one that failed and those that come after as well. Shouldn't
-the note only apply to the arguments that were successfully locked?
+Related to 951.
 
    
 
 
    
-Further discussion and possible resolutions in c++std-lib-23049.
+20.9.1 [time.clock.req] says that a clock's rep member is "an
+arithmetic type or a class emulating an arithmetic type." What are the
+requirements for such a type?
 
    
 
 
    [
-Summit:
+2009-05-10 Howard adds:
 ]
    
 
+
 
    
-Move to review. Agree with proposed resolution.
+This wording was aimed directly at the ArithmeticLike concept.
 
    
 
 
    [
@@ -25506,161 +19389,361 @@ Batavia (2009-05):
 ]
    
 
 
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
+
    
+We recommend this issue be addressed in the context of providing concepts
+for the entire thread header.
+
    
+
    
+May resolve for now by specifying arithmetic types,
+and in future change to ArithmeticLike.
+However, Alisdair believes this is not feasible.
+
    
+
    
+Bill disagrees.
+
    
+
    
+We look forward to proposed wording.  Move to Open.
+
    
 
    
 
+
    [
+2009-08-01 Howard adds:
+]
    
 
-
    Proposed resolution:
    
-
-
    
-Change 30.4.4 [thread.lock.algorithm], p2:
-
    
 
 
    
--2- Effects: Calls try_lock() for each argument in order
-beginning with the first until all arguments have been processed or a
-call to try_lock() fails, either by returning false or by throwing an
-exception. If a call to try_lock() fails, unlock() shall be called for
-all prior arguments and there shall be no further calls to try_lock().
+See commented dated 2009-08-01 in 951.
 
    
 
+
+
    Proposed resolution:
    
 
    
-Delete the note from 30.4.4 [thread.lock.algorithm], p3
 
    
 
-
    
--3- Returns: -1 if all calls to try_lock() returned true,
-otherwise a 0-based index value that indicates 
-the argument for which try_lock() returned false. [Note:
-On return, either all arguments will be 
-locked or none will be locked. -- end note]
-
    
-
 
 
 
 
 
    
-
    987. reference_wrapper and function types
    
-
    Section: 20.7.5 [refwrap] Status: Review
- Submitter: Howard Hinnant Opened: 2009-02-18  Last modified: 2009-05-23
    
-
    View all other issues in [refwrap].
    
+
    954. Various threading bugs #4
    
+
    Section: 20.9.1 [time.clock.req] Status: Review
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-08-01
    
+
    View other active issues in [time.clock.req].
    
+
    View all other issues in [time.clock.req].
    
 
    View all issues with Review status.
    
 
    Discussion:
    
 
    
-The synopsis in 20.7.5 [refwrap] says:
+Table 55 -- Clock Requirements (in 20.9.1 [time.clock.req])
 
    
 
-
    template <ObjectType T> class reference_wrapper
-...
-
    
+
      
+
    1. 
+the requirements for C1::time_point require C1 and C2
+to "refer to the same epoch", but "epoch" is not defined.
+
      2. 
+
    2. 
+"Different clocks may share a time_point definition if it is
+valid to compare their time_points by comparing their
+respective durations." What does "valid" mean here? And, since
+C1::rep is "**THE** representation type of the native
+duration and time_point" (emphasis added), there
+doesn't seem to be much room for some other representation.
+
      3. 
+
    3. 
+C1::is_monotonic has type "const bool". The
+"const" should be removed.
+
      4. 
+
    4. 
+C1::period has type ratio. ratio isn't a type, 
+it's a template. What is the required type?
+
      5. 
+
    
+
+
    [
+2009-05-10 Howard adds:
+]
    
+
 
+
      
+
    1. 
 
      
-And then paragraph 3 says:
+"epoch" is purposefully not defined beyond the common English
+definition.  The C standard
+also chose not to define epoch, though POSIX did.  I believe it is a strength
+of the C standard that epoch is not defined.  When it is known that two time_points
+refer to the same epoch, then a definition of the epoch is not needed to compare
+the two time_points, or subtract them.
+
      
+
      
+A time_point and a Clock implicitly refer to an (unspecified) epoch.
+The time_point represents an offset (duration) from an epoch.
+
      
+
      2. 
+
    2. 
+
      
+The sentence:
 
      
-
 
      
+Different clocks 
+may share a time_point
+definition if it is valid to 
+compare their time_points by 
+comparing their respective 
+durations.
+
      
+
 
      
-The template instantiation reference_wrapper<T> shall be
-derived from std::unary_function<T1, R> only if the type
-T is any of the following:
+is redundant and could be removed.  I believe the sentence which follows the above:
 
      
 
-
        
+
        
+C1 and C2 shall refer to the same epoch.
+
        
+
+
        
+is sufficient.  If two clocks share the same epoch, then by definition, comparing
+their time_points is valid.
+
        
+
 
      • 
-a function type or a pointer to function type taking one argument of
-type T1 and returning R
+is_monotonic is meant to never change (be const).  It is also
+desired that this value be usable in compile-time computation and branching.
 
        • 
-
      
+
    3. 
+
      
+This should probably instead be worded:
+
      
+
      
+An instantiation of ratio.
 
      
+
      4. 
+
    
 
+
    [
+Batavia (2009-05):
+]
    
+
+
    
 
    
-But function types are not ObjectTypes.
+Re (a): It is not clear to us whether "epoch" is a term of art.
 
    
-
 
    
-Paragraph 4 contains the same contradiction.
+Re (b), (c), and (d):  We agree with Howard's comments,
+and would consider adding to (c) a static constexpr requirement.
+
    
+
    
+Move to Open pending proposed wording.
 
    
+
    
 
 
    [
-Post Summit:
+2009-05-25 Daniel adds:
+]
    
+
+
+
    
+In regards to (d) I suggest to say "a specialization of ratio" instead of
+"An instantiation of ratio". This seems to be the better matching standard
+core language term for this kind of entity.
+
    
+
+
    [
+2009-05-25 Ganesh adds:
 ]
    
 
 
 
    
 
    
-Jens: restricted reference to ObjectType
+Regarding (a), I found this paper on the ISO website using the term "epoch" consistently with the current wording:
 
    
+
 
    
-Recommend Review.
+http://standards.iso.org/ittf/PubliclyAvailableStandards/C030811e_FILES/MAIN_C030811e/text/ISOIEC_18026E_TEMPORAL_CS.HTM
+
    
+
    
+which is part of ISO/IEC 18026 "Information technology -- Spatial Reference Model (SRM)".
 
    
 
    
 
 
    [
-Post Summit, Peter adds:
+2009-08-01 Howard: Moved to Reivew as the wording requested in Batavia has been provided.
 ]
    
 
 
+
+
+
    Proposed resolution:
    
+
      
+
    1. 
+
      
+Change 20.9.1 [time.clock.req] p1:
+
      
 
      
+-1- A clock is a bundle consisting of a native duration, a native time_point, and a function now() to get the 
+current time_point.  The origin of the clock's time_point is referred to as the clock's epoch as defined in 
+section 6.3 of ISO/IEC 18026.
+A clock shall meet the requirements in Table 45.
+
      
+
      2. 
+
    2. 
 
      
-In https://svn.boost.org/trac/boost/ticket/1846
-however Eric Niebler makes the very reasonable point that reference_wrapper<F>,
-where F is a function type, represents a reference to a function,
-a legitimate entity. So boost::ref was changed to allow it.
+Remove the sentence from the time_point row of the table "Clock Requirements":
 
      
+
+
+
+
+
+
+
+
      Clock requirements
      
+C1::time_point
+
+chrono::time_point<C1> or chrono::time_point<C2, C1::duration>
+
+The native time_point type of the clock.
+Different clocks may share a time_point definition if it is valid to compare their time_points by comparing their respective durations.
+C1 and C2 shall refer to the same epoch.
+
      
+
      3. 
+
    
+
      
+
    1. 
 
      
-https://svn.boost.org/trac/boost/browser/trunk/libs/bind/test/ref_fn_test.cpp
+Change the row starting with C1::period of the table "Clock Requirements":
 
      
+
+
+
+
+
+
+
+
      Clock requirements
      
+C1::period
+
+a specialization of ratio
+
+The tick period of the clock in seconds.
+
      
+
+
      2. 
+
    
+
+
+
+
+
+
    
+
    955. Various threading bugs #5
    
+
    Section: 20.9.1 [time.clock.req] Status: Open
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-06-07
    
+
    View other active issues in [time.clock.req].
    
+
    View all other issues in [time.clock.req].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
 
    
-Therefore, I believe an alternative proposed resolution for issue 987 could simply
-allow reference_wrapper to be used with function types.
+20.9.1 [time.clock.req] requires that a clock type have a member
+typedef named time_point that names an instantiation of the
+template time_point, and a member named duration that
+names an instantiation of the template duration. This mixing of
+levels is confusing. The typedef names should be different from the
+template names.
 
    
-
    
 
 
    [
-Post Summit, Howard adds:
+Post Summit, Anthony provided proposed wording.
+]
    
+
+
+
    [
+2009-05-04 Howard adds:
 ]
    
 
 
 
    
 
    
-I agree with Peter (and Eric).  I got this one wrong on my first try.  Here
-is code that demonstrates how easy (and useful) it is to instantiate
-reference_wrapper with a function type:
+The reason that the typedef names were given the same name as the class templates
+was so that clients would not have to stop and think about whether they were
+using the clock's native time_point / duration or the class
+template directly.  In this case, one person's confusion is another person's
+encapsulation.  The detail that sometimes one is referring to the clock's
+native types, and sometimes one is referring to an independent type is
+purposefully "hidden" because it is supposed to be an unimportant
+detail.  It can be confusing to have to remember when to type duration
+and when to type duration_type, and there is no need to require the
+client to remember something like that.
 
    
 
-
    #include <functional>
-
-template <class F>
-void test(F f);
-
-void f() {}
+
    
+For example, here is code that I once wrote in testing out the usability of
+this facility:
+
    
 
-int main()
+
    template <class Clock, class Duration>
+void do_until(const std::chrono::time_point<Clock, Duration>& t)
 {
-    test(std::ref(f));
+    typename Clock::time_point now = Clock::now();
+    if (t > now)
+    {
+        typedef typename std::common_type
+        <
+            Duration,
+            typename std::chrono::system_clock::duration
+        >::type CD;
+        typedef std::chrono::duration<double, std::nano> ID;
+
+        CD d = t - now;
+        ID us = duration_cast<ID>(d);
+        if (us < d)
+            ++us;
+        ...
+    }
 }
 
    
 
 
    
-Output (link time error shows type of reference_wrapper instantiated
-with function type):
+I see no rationale to require the client to append _type to some
+of those declarations.  It seems overly burdensome on the author of do_until:
 
    
 
-
    Undefined symbols:
-  "void test<std::reference_wrapper<void ()()> >(std::reference_wrapper<void ()()>)",...
+
    template <class Clock, class Duration>
+void do_until(const std::chrono::time_point<Clock, Duration>& t)
+{
+    typename Clock::time_point_type now = Clock::now();
+    if (t > now)
+    {
+        typedef typename std::common_type
+        <
+            Duration,
+            typename std::chrono::system_clock::duration_type
+        >::type CD;
+        typedef std::chrono::duration<double, std::nano> ID;
+
+        CD d = t - now;
+        ID us = duration_cast<ID>(d);
+        if (us < d)
+            ++us;
+        ...
+    }
+}
 
    
 
 
    
-I've taken the liberty of changing the proposed wording to allow function types
-and set to Open.  I'll also freely admit that I'm not positive ReferentType
-is the correct concept.
+Additionally I'm fairly certain that this suggestion hasn't been implemented.
+If it had, it would have been discovered that it is incomplete.  time_point
+also has a nested type (purposefully) named duration.
 
    
-
+
    
+That is, the current proposed wording would put the WP into an inconsistent state.
 
    
+
    
+In contrast,
+the current WP has been implemented and I've received very favorable feedback
+from people using this interface in real-world code.
+
    
 
-
+
    
 
 
    [
 Batavia (2009-05):
@@ -25668,190 +19751,255 @@ Batavia (2009-05):
 
 
    
 
    
-Howard observed that FunctionType,
-a concept not (yet?) in the Working Paper,
-is likely the correct constraint to be applied.
-However, the proposed resolution provides an adequate approximation.
+Bill agrees that distinct names should be used for distinct kinds of entities.
 
    
 
    
-Move to Review.
+Walter would prefer not to suffix type names,
+especially for such well-understood terms as "duration".
+
    
+
    
+Howard reminds us that the proposed resolution is incomplete, per his comment
+in the issue.
+
    
+
    
+Move to Open.
 
    
 
    
 
 
    [
-2009-05-23 Alisdair adds:
+2009-06-07 Howard adds:
 ]
    
 
 
 
    
 
    
-By constraining to PointeeType we rule out the ability for T to be a
-reference, and call in reference-collapsing.  I'm not sure if this is
-correct and intended, but would like to be sure the case was considered.
-
    
-
    
-Is dis-allowing reference types and the
-implied reference collapsing the intended result?
+Not meaning to be argumentative, but we have a decade of positive experience
+with the precedent of using the same name for the nested type as an external
+class representing an identical concept.
 
    
-
    
 
+
    template<class Category, class T, class Distance = ptrdiff_t,
+         class Pointer = T*, class Reference = T&>
+struct iterator
+{
+    ...
+};
+
+template <BidirectionalIterator Iter>
+class reverse_iterator
+{
+    ...
+};
 
+template <ValueType T, Allocator Alloc = allocator<T> >
+    requires NothrowDestructible<T>
+class list
+{
+public:
+    typedef implementation-defined     iterator;
+    ...
+    typedef reverse_iterator<iterator> reverse_iterator;
+    ...
+};
+
    
 
-
    Proposed resolution:
    
 
    
-Change the synopsis in 20.7 [function.objects]:
+I am aware of zero complaints regarding the use of iterator
+and reverse_iterator as nested types of the containers despite these
+names also having related meaning at namespace std scope.
 
    
 
-
    // 20.6.5, reference_wrapper:
-template <ObjectType ReferentType T>
-  requires PointeeType<T>
-  class reference_wrapper;
-
-template <ObjectType PointeeType T>
-  reference_wrapper<T> ref(T&);
-
-template <ObjectType PointeeType T>
-  reference_wrapper<const T> cref(const T&);
+
    
+Would we really be doing programmers a favor by renaming these nested types?
+
    
 
-template <ObjectType PointeeType T>
-  reference_wrapper<T> ref(reference_wrapper<T>);
-template <ObjectType PointeeType T>
-  reference_wrapper<const T> cref(reference_wrapper<T>);
+
    template <ValueType T, Allocator Alloc = allocator<T> >
+    requires NothrowDestructible<T>
+class list
+{
+public:
+    typedef implementation-defined     iterator_type;
+    ...
+    typedef reverse_iterator<iterator> reverse_iterator_type;
+    ...
+};
 
    
 
 
    
-Change the synopsis in 20.7.5 [refwrap]:
+I submit that such design contributes to needless verbosity which ends up
+reducing readability.
 
    
+
    
 
-
    template <ObjectType ReferentType T>
-  requires PointeeType<T>
-  class reference_wrapper
-   ...
-
    
 
+
+
    Proposed resolution:
    
 
    
-Change the prototypes in 20.7.5.5 [refwrap.helpers]:
+Change 20.9 [time]:
 
    
 
-
    template <ObjectType PointeeType T>
-  reference_wrapper<T> ref(T&);
-...
-template <ObjectType PointeeType T>
-  reference_wrapper<const T> cref(const T&);
-...
-template <ObjectType PointeeType T>
-  reference_wrapper<T> ref(reference_wrapper<T>);
+
    ...
+template <class Clock, class Duration = typename Clock::duration_type> class time_point;
 ...
-template <ObjectType PointeeType T>
-  reference_wrapper<const T> cref(reference_wrapper<T>);
 
    
 
-
-
-
    Rationale:
    
-
    
-a) The occurrence of T& in the function signature auto-implies
-std::ReferentType,
-this is due to 14.11.1.2 [temp.req.impl]/4 bullet 4
-
    
 
    
-b) The occurrence of the constrained template reference_wrapper<T> in
-the remaining
-signatures lets kick in 14.11.1.2 [temp.req.impl]/4 bullet 1 and adds *all* requirements of
-this template. But we need to add at least *one* requirement (and it
-was an arbitrary,
-but natural decision to require std::PointeeType here) to *activate*
-this. If we hadn't done
-this, we were in unconstrained mode!
+Change 20.9.1 [time.clock.req]:
 
    
 
+
    
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
    Table 45 -- Clock requirements
    ExpressionReturn typeOperational semantics
    .........
    C1::duration_typechrono::duration<C1::rep, C1::period>The native duration type of the clock.
    C1::time_point_typechrono::time_point<C1> or chrono::time_point<C2, C1::duration_type<The native time_point type of the clock.   Different clocks may  share a time_point_type
+definition if it is valid to 
+compare their time_point_types by 
+comparing their respective 
+duration_types. C1 and C2 shall 
+refer to the same epoch.
    .........
    C1::now()C1::time_point_typeReturns a time_point_type object 
+representing the current point 
+in time.
+
    
+
    
 
-
-
-
-
    
-
    988. Reflexivity meaningless?
    
-
    Section: 20.2.6 [concept.comparison] Status: Tentatively NAD
- Submitter: Alisdair Meredith Opened: 2009-02-24  Last modified: 2009-05-23
    
-
    View other active issues in [concept.comparison].
    
-
    View all other issues in [concept.comparison].
    
-
    View all issues with Tentatively NAD status.
    
-
    Discussion:
    
 
    
-20.2.6 [concept.comparison] p2:
+Change 20.9.5.1 [time.clock.system]:
 
    
+
+
    
 
    
-Due to the subtle meaning of == inside axioms, the Reflexivity axiom does
-not do anything as written. It merely states that a value is substitutable
-with itself, rather than asserting a property of the == operator.
+-1- Objects of class system_clock represent wall clock time from the system-wide realtime clock.
 
    
 
-
-Original proposed resolution:
-
+
    class system_clock { 
+public: 
+  typedef see below rep; 
+  typedef ratio<unspecified, unspecified> period; 
+  typedef chrono::duration<rep, period> duration_type; 
+  typedef chrono::time_point<system_clock> time_point_type; 
+  static const bool is_monotonic = unspecified ; 
+
+  static time_point_type now(); 
+
+  // Map to C API 
+  static time_t to_time_t (const time_point_type& t); 
+  static time_point_type from_time_t(time_t t); 
+};
+
    
 
 
    
-Change the definition of Reflexivity in 20.2.6 [concept.comparison]:
+-2- system_clock::duration_type::min() < system_clock::duration_type::zero() shall be true.
 
    
 
-
    axiom Reflexivity(T a) { (a == a) == true; }
-
    
+
    time_t to_time_t(const time_point_type& t);
+
    
 
-
    [
-Post Summit:
-]
    
+
    
+-3- Returns: A time_t object that represents the same
+point in time as t when both values are truncated to the
+coarser of the precisions of time_t and time_point_type.
+
    
 
+
    time_point_type from_time_t(time_t t);
+
    
 
 
    
+-4- Returns: A time_point_type object that represents the same point
+in time as t when both values are truncated to the coarser of the
+precisions of time_t and time_point_type.
+
    
+
    
+
 
    
-Alisdair: I was wrong.
-
    
-
    
-Recommend NAD.
+Change 20.9.5.2 [time.clock.monotonic]:
 
    
-
    
 
+
    class monotonic_clock { 
+public: 
+  typedef unspecified                                rep; 
+  typedef ratio<unspecified , unspecified>           period; 
+  typedef chrono::duration<rep, period>              duration_type; 
+  typedef chrono::time_point<unspecified , duration_type> time_point_type; 
+  static const bool is_monotonic =                   true; 
 
+  static time_point_type now();
+};
+
    
 
-
    Proposed resolution:
    
 
    
-NAD.
+Change 20.9.5.3 [time.clock.hires]:
 
    
 
+
    class high_resolution_clock { 
+public: 
+  typedef unspecified                                rep; 
+  typedef ratio<unspecified , unspecified>           period; 
+  typedef chrono::duration<rep, period>              duration_type; 
+  typedef chrono::time_point<unspecified , duration_type> time_point_type; 
+  static const bool is_monotonic =                   true; 
+
+  static time_point_type now();
+};
+
    
+
+
 
 
 
 
 
    
-
    989. late_check and library
    
-
    Section: 17 [library] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-02-24  Last modified: 2009-05-23
    
-
    View other active issues in [library].
    
-
    View all other issues in [library].
    
+
    956. Various threading bugs #6
    
+
    Section: 20.9.1 [time.clock.req] Status: Open
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-05-23
    
+
    View other active issues in [time.clock.req].
    
+
    View all other issues in [time.clock.req].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-The example in 6.9p2 shows how late_check blocks inhibit concept_map lookup
-inside a constrained context, and so inhibit concept map adaption by users
-to meet template requirements.
-
    
-
    
-Do we need some text in clause 17 prohibitting use of late_check in library
-template definitions unless otherwise documented?
+20.9.1 [time.clock.req] uses the word "native" in several places,
+but doesn't define it. What is a "native duration"?
 
    
 
 
    [
-Doug adds:
+2009-05-10 Howard adds:
 ]
    
 
 
 
    
-We need something like this, but it should be a more general statement
-about implementations respecting the concept maps provided by the
-user. Use of late_check is one way in which implementations can
-subvert the concept maps provided by the user, but there are other
-ways as well ("pattern-based" overloading, tricks with "auto" concept
-maps and defaulted associated type arguments).
+The standard uses "native" in several places without defining it (e.g.
+2.14.3 [lex.ccon]).  It is meant to mean "that which is defined
+by the facility", or something along those lines.  In this case it refers
+to the nested time_point and duration types of the clock.
+Better wording is welcome.
 
    
 
 
    [
@@ -25859,254 +20007,248 @@ Batavia (2009-05):
 ]
    
 
 
    
-Move to Open, pending proposed wording from Alisdair and/or Doug for further review.
+Move to Open pending proposed wording from Pete.
 
    
 
 
 
    Proposed resolution:
    
+
    
+
    
 
 
 
 
 
 
    
-
    990. monotonic_clock::is_monotonic must be true
    
-
    Section: 20.9.5.2 [time.clock.monotonic] Status: Tentatively Ready
- Submitter: Howard Hinnant Opened: 2009-03-09  Last modified: 2009-05-23
    
-
    View all issues with Tentatively Ready status.
    
+
    957. Various threading bugs #7
    
+
    Section: 20.9.5.1 [time.clock.system] Status: Review
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-05-23
    
+
    View all other issues in [time.clock.system].
    
+
    View all issues with Review status.
    
 
    Discussion:
    
 
    
-There is some confusion over what the value of monotonic_clock::is_monotonic
-when monotonic_clock is a  synonym for system_clock.  The
-intent is that if monotonic_clock exists, then monotonic_clock::is_monotonic
-is true.
+20.9.5.1 [time.clock.system]: to_time_t is overspecified. It
+requires truncation, but should allow rounding. For example, suppose a
+system has a clock that gives times in milliseconds, but time() rounds
+those times to the nearest second. Then system_clock can't use any
+resolution finer than one second, because if it did, truncating times
+between half a second and a full second would produce the wrong time_t
+value.
 
    
 
 
    [
-Batavia (2009-05):
+Post Summit Anthony Williams provided proposed wording.
 ]
    
 
-
    
-
    
-We agree with the proposed resolution.
-
    
-
    
-Move to Tentatively Ready.
-
    
-
    
-
 
-
    Proposed resolution:
    
-
    
-Change 20.9.5.2 [time.clock.monotonic], p1:
-
    
+
    [
+Batavia (2009-05):
+]
    
 
 
    
--1- Objects of class monotonic_clock represent clocks for which
-values of time_point never decrease as physical time advances.
-monotonic_clock may be a synonym for system_clock
-if and only if system_clock::is_monotonic is
-true.
+Move to Review pending input from Howard. and other stakeholders.
 
    
 
-
-
-
-
-
    
-
    991. Response to JP 50
    
-
    Section: 22.3.3.2.2 [conversions.string] Status: Tentatively Ready
- Submitter: P.J. Plauger Opened: 2009-03-03  Last modified: 2009-05-23
    
-
    View other active issues in [conversions.string].
    
-
    View all other issues in [conversions.string].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
-
    
-Add custom allocator parameter to wstring_convert, since we cannot
-allocate memory for strings from a custom allocator.
-
    
-
 
    [
-Batavia (2009-05):
+2009-05-23 Howard adds:
 ]
    
 
+
 
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
+I am in favor of the wording provided by Anthony.
 
    
 
 
 
    Proposed resolution:
    
 
    
-Change 22.3.3.2.2 [conversions.string]:
-
    
-
-
    template<class Codecvt, class Elem = wchar_t,
-         class Wide_alloc = std::allocator<Elem>,
-         class Byte_alloc = std::allocator<char> > class wstring_convert {
-  public:
-    typedef std::basic_string<char, char_traits<char>, Byte_alloc> byte_string;
-    typedef std::basic_string<Elem, char_traits<Elem>, Wide_alloc> wide_string;
-     ...
-
    
-
-
    
-Change 22.3.3.2.2 [conversions.string], p3:
+In 20.9.5.1 [time.clock.system] replace paragraphs 3 and 4 with:
 
    
 
 
    
--3- The class template describes an ob ject that controls conversions
-between wide string ob jects of class
-std::basic_string<Elem, char_traits<Elem>, Wide_alloc>
-and byte string objects of class
-std::basic_string<char, char_traits<char>, Byte_alloc>
-(also known as std::string).
+
    time_t to_time_t(const time_point& t);
+
    
+
    
+-3- Returns: A time_t object that represents the same
+point in time as t when both values are truncated
+restricted to the coarser of the precisions of
+time_t and time_point.  It is implementation
+defined whether values are rounded or truncated to the required
+precision.
 
    
 
+
    time_point from_time_t(time_t t);
+
    
+
    
+-4- Returns: A time_point object that represents the
+same point in time as t when both values are truncated
+restricted to the
+coarser of the precisions of time_t and time_point.
+It is implementation defined whether values are
+rounded or truncated to the required precision.
+
    
+
    
 
 
 
 
 
 
    
-
    992. Response to UK 169
    
-
    Section: 17.6.1.1 [contents] Status: Open
- Submitter: P.J. Plauger Opened: 2009-03-03  Last modified: 2009-05-23
    
-
    View other active issues in [contents].
    
-
    View all other issues in [contents].
    
+
    958. Various threading bugs #8
    
+
    Section: 30.5.1 [thread.condition.condvar] Status: Open
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-08-01
    
+
    View other active issues in [thread.condition.condvar].
    
+
    View all other issues in [thread.condition.condvar].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-This phrasing contradicts later freedom to implement the C standard
-library portions in the global namespace as well as std. (17.6.2.3p4)
+30.5.1 [thread.condition.condvar]: the specification for wait_for
+with no predicate has an effects clause that says it calls wait_until,
+and a returns clause that sets out in words how to determine the return
+value. Is this description of the return value subtly different from the
+description of the value returned by wait_until? Or should the effects
+clause and the returns clause be merged?
 
    
 
 
    [
-Batavia (2009-05):
+Summit:
 ]
    
 
+
 
    
-The proposed wording seems to go too far.
-Move back to Open.
+Move to open. Associate with LWG 859 and any other monotonic-clock
+related issues.
 
    
 
+
    [
+2009-08-01 Howard adds:
+]
    
 
-
    Proposed resolution:
    
-
    
-Change 17.6.1.1 [contents], p2:
-
    
 
 
    
--2- All library entities except those from the Standard C
-library, macros, operator new and operator
-delete are defined within the namespace std or namespaces
-nested within namespace std.
+I believe that 859 (currently Ready) addresses this issue, and
+that this issue should be marked NAD, solved by 859 (assuming
+it moves to WP).
 
    
 
 
 
+
    Proposed resolution:
    
+
    
+
    
+
+
 
 
 
 
    
-
    993. Response to UK 188
    
-
    Section: 18.5 [support.start.term] Status: Tentatively Ready
- Submitter: P.J. Plauger Opened: 2009-03-03  Last modified: 2009-05-23
    
-
    View all other issues in [support.start.term].
    
-
    View all issues with Tentatively Ready status.
    
+
    959. Various threading bugs #9
    
+
    Section: 30.5.1 [thread.condition.condvar] Status: Open
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-08-01
    
+
    View other active issues in [thread.condition.condvar].
    
+
    View all other issues in [thread.condition.condvar].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-The function _Exit does not appear to be defined in this standard.
-Should it be added to the table of functions included-by-reference to
-the C standard?
+30.5.1 [thread.condition.condvar]: condition_variable::wait_for
+is required to compute the absolute time by adding the duration value to
+chrono::monotonic_clock::now(), but monotonic_clock is not required to
+exist.
 
    
 
 
    [
-2009-05-09 Alisdair fixed some minor issues in the wording.
+Summit:
 ]
    
 
 
-
    [
-Batavia (2009-05):
-]
    
-
 
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
+Move to open. Associate with LWG 859 and any other monotonic-clock
+related issues.
 
    
 
+
    [
+2009-08-01 Howard adds:
+]
    
 
-
    Proposed resolution:
    
-
    
-Add to 18.5 [support.start.term] Table 20 (Header
-<cstdlib> synopsis) Functions:
-
    
 
-
    _Exit
-
    
+
    
+I believe that 859 (currently Ready) addresses this issue, and
+that this issue should be marked NAD, solved by 859 (assuming
+it moves to WP).
+
    
 
-
    
-Add before the description of abort(void):
-
    
 
-
    void _Exit [[noreturn]] (int status)
-
    
 
-
    
+
    Proposed resolution:
    
 
    
-The function _Exit(int status) has additional behavior in this
-International Standard:
 
    
-
      
-
    • 
-The program is terminated without executing destructors for objects of
-automatic, thread, or static storage duration and without calling the
-functions passed to atexit() (3.6.3 [basic.start.term]).
-
      • 
-
    
-
    
-
    
-
 
 
 
 
 
 
    
-
    994. Response to UK 193
    
-
    Section: 18.6.2.2 [new.handler] Status: Tentatively Ready
- Submitter: P.J. Plauger Opened: 2009-03-03  Last modified: 2009-05-23
    
-
    View all issues with Tentatively Ready status.
    
+
    960. Various threading bugs #10
    
+
    Section: 30.4.1 [thread.mutex.requirements] Status: Open
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-03-27
    
+
    View other active issues in [thread.mutex.requirements].
    
+
    View all other issues in [thread.mutex.requirements].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-quick_exit has been added as a new valid way to terminate a program in a
-well defined way
+30.4.1 [thread.mutex.requirements]: paragraph 4 is entitled
+"Error conditions", but according to 17.5.1.4 [structure.specifications], "Error
+conditions:" specifies "the error conditions for error codes reported by
+the function." It's not clear what this should mean when there is no
+function in sight.
 
    
 
 
    [
-Batavia (2009-05):
+Summit:
 ]
    
 
+
 
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
+Move to open.
 
    
 
+
    [
+Beman provided proposed wording.
+]
    
+
+
 
 
    Proposed resolution:
    
 
    
-Change 18.6.2.2 [new.handler], p2:
+Change 30.4.1 [thread.mutex.requirements] Mutex requirements,
+paragraph 4 as indicated:
 
    
 
 
    
 
    
--2- Required behavior: ...
+-4- Error conditions:
+The error conditions for error codes, if any, reported by member
+functions of type Mutex shall be:
 
    
 
      
-
    • ...
      • 
 
    • 
-call either abort() or exit();
-terminate execution of the program without returning to the caller
+not_enough_memory -- if there is not enough memory to construct
+the mutex object.
+
      • 
+
    • 
+resource_unavailable_try_again -- if any native handle type
+manipulated is not available.
+
      • 
+
    • 
+operation_not_permitted -- if the thread does not have the
+necessary permission to change the state of the mutex object.
+
      • 
+
    • 
+device_or_resource_busy -- if any native handle type
+manipulated is already locked.
+
      • 
+
    • 
+invalid_argument -- if any native handle type manipulated as
+part of mutex construction is incorrect.
 
      • 
 
    
 
    
@@ -26115,34 +20257,34 @@ Change 18.6.2.2 [new.handler], p2:
 
 
 
-
-
 
    
-
    995. Operational Semantics Unclear
    
-
    Section: 17.5.1.3 [structure.requirements] Status: Tentatively NAD
- Submitter: David Abrahams Opened: 2009-03-06  Last modified: 2009-05-23
    
-
    View all issues with Tentatively NAD status.
    
+
    961. Various threading bugs #11
    
+
    Section: 30.4.1 [thread.mutex.requirements] Status: Open
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-03-22
    
+
    View other active issues in [thread.mutex.requirements].
    
+
    View all other issues in [thread.mutex.requirements].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-As a practical matter there's disagreement on the meaning of operational
-semantics.  If the text in 17.5.1.3 [structure.requirements]p4 isn't
-clear, it should be clarified.  However, it's not clear whether the
-disagreement is merely due to people not being aware of the text.
+30.4.1 [thread.mutex.requirements] describes required member
+functions of mutex types, and requires that they throw exceptions under
+certain circumstances. This is overspecified. User-defined types can
+abort on such errors without affecting the operation of templates
+supplied by standard-library.
 
    
 
 
    [
-Batavia (2009-05):
+Summit:
 ]
    
 
 
    
-Agree with the recommended NAD resolution.
+Move to open. Related to conceptualization and should probably be
+tackled as part of that.
 
    
 
 
 
    Proposed resolution:
    
 
    
-Recommend NAD.  The text in 17.5.1.3 [structure.requirements] is
-perfectly clear.
 
    
 
 
@@ -26150,790 +20292,622 @@ perfectly clear.
 
 
 
    
-
    996. Move operation not well specified
    
-
    Section: 17 [library] Status: Open
- Submitter: David Abrahams Opened: 2009-03-06  Last modified: 2009-05-23
    
-
    View other active issues in [library].
    
-
    View all other issues in [library].
    
-
    View all issues with Open status.
    
+
    962. Various threading bugs #12
    
+
    Section: 30.4.3.2.2 [thread.lock.unique.locking] Status: Review
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-07-21
    
+
    View other active issues in [thread.lock.unique.locking].
    
+
    View all other issues in [thread.lock.unique.locking].
    
+
    View all issues with Review status.
    
 
    Discussion:
    
 
    
-There are lots of places in the standard where we talk about "the move
-constructor" but where we mean "the move operation," i.e.  T( move( x ) ).
-
    
-
    
-We also don't account for whether that operation modifies x or not, and
-we need to.
+30.4.3.2.2 [thread.lock.unique.locking]:  unique_lock::lock is
+required to throw an object of type std::system_error "when the
+postcondition cannot be achieved." The postcondition is owns == true,
+and this is trivial to achieve. Presumably, the requirement is intended
+to mean something more than that.
 
    
 
 
    [
-Batavia (2009-05):
+Summit:
 ]
    
 
 
    
-Move to Open, pending proposed wording from Dave for further
-review.
+Move to open.
 
    
 
+
    [
+Beman has volunteered to provide proposed wording.
+]
    
 
-
    Proposed resolution:
    
-
    
-
    
 
+
    [
+2009-07-21 Beman added wording to address 30.2.2 [thread.req.exception]
+in response to the Frankfurt notes in 859.
+]
    
 
 
 
 
-
    
-
    997. Response to UK 163
    
-
    Section: 17.5.1.4 [structure.specifications] Status: Tentatively Ready
- Submitter: Thomas Plum Opened: 2009-03-03  Last modified: 2009-05-23
    
-
    View other active issues in [structure.specifications].
    
-
    View all other issues in [structure.specifications].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
-
    
-Many functions are defined as "Effects: Equivalent to a...", which seems
-to also define the preconditions, effects, etc. But this is not made
-clear.
-
    
+
    Proposed resolution:
    
 
-
    
-After studying the occurrences of "Effects: Equivalent to", I agree with
-the diagnosis but disagree with the solution.  In 21.4.2 [string.cons]
-we find
-
    
+
    Change Exceptions 30.2.2 [thread.req.exception] as indicated:
    
+
    
+
    Some functions described in this Clause are specified to throw exceptions of 
+type system_error (19.5.5). Such exceptions shall be thrown if 
+any of the Error conditions are detected or a call to an operating 
+system or other underlying API results in an error that prevents the library 
+function from satisfying its postconditions or from returning a meaningful 
+value meeting its specifications. Nevertheless, failure to 
+allocate storage shall be reported as described in [res.on.exception.handling].
    
+
    
 
+
    Change thread assignment 30.3.1.4 [thread.thread.assign], join(), 
+paragraph 8 as indicated:
    
 
    
-
    
-14 Effects: If InputIterator is an integral type, equivalent to
-basic_string(static_cast<size_type>(begin), static_cast<value_type>(end), a)
-
    
-
    
-15 Otherwise constructs a string from the values in the range [begin,
-end), as indicated in the Sequence Requirements table (see 23.1.3).
-
    
+
    Throws: std::system_error when the postconditions cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
+
 
    
 
-
    
-This would be devishly difficult to re-write with an explicit
-"Equivalent to:" clause.  Instead, I propose the following, which will
-result in much less editorial re-work.
-
    
+
    Change thread assignment 30.3.1.4 [thread.thread.assign], detach(), paragraph 
+13 as indicated:
    
+
    
 
-
    [
-2009-05-09 Alisdair adds:
-]
    
+
    Throws: std::system_error when the effects or 
+postconditions cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
 
+
    
 
+
    Change Mutex requirements 30.4.1 [thread.mutex.requirements], paragraph 
+11, as indicated:
    
 
    
-This issue is related to 492.
+
+
    Throws: std::system_error when the effects or 
+postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
 
    
+
    Change unique_lock locking 30.4.3.2.2 [thread.lock.unique.locking], 
+paragraph 3, as indicated:
    
+
    
 
-
    [
-Batavia (2009-05):
-]
    
+
    Throws: std::system_error when the  postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
+
    
+
    Change unique_lock locking 30.4.3.2.2 [thread.lock.unique.locking], 
+paragraph 8, as indicated:
    
+
    
 
+
    Throws: std::system_error when the  postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
+
    
+
    Change unique_lock locking 30.4.3.2.2 [thread.lock.unique.locking], 
+paragraph 13, as indicated:
    
 
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
+
+
    Throws: std::system_error when the  postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
 
    
+
    Change unique_lock locking 30.4.3.2.2 [thread.lock.unique.locking], 
+paragraph 18, as indicated:
    
+
    
 
+
    Throws: std::system_error when the  postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
+
    
+
    Change unique_lock locking 30.4.3.2.2 [thread.lock.unique.locking], 
+paragraph 22, as indicated:
    
+
    
 
-
    Proposed resolution:
    
-
    
-Add a new paragraph after 17.5.1.4 [structure.specifications], p3:
-
    
+
    Throws: std::system_error when the  postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
+
    
+
    Change Function call_once 30.4.5.2 [thread.once.callonce], paragraph 4, as 
+indicated
    
+
    
+  
    Throws: std::system_error when the effects cannot be achieved an exception is required (30.2.2 [thread.req.exception]), 
+  or any exception thrown by func.
    
+
    
+
    Change Class condition_variable 30.5.1 [thread.condition.condvar], 
+paragraph 12, as indicated:
    
+
    
 
+
    Throws: std::system_error when the effects or 
+postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
+
    
+
    Change Class condition_variable 30.5.1 [thread.condition.condvar], 
+paragraph 19, as indicated:
    
 
    
-
    
--3- Descriptions of function semantics contain the following elements (as appropriate):154
-
    
 
-
      
-
    • 
-Requires: the preconditions for calling the function
-
      • 
-
    • 
-Effects: the actions performed by the function
-
      • 
-
    • 
-Postconditions: the observable results established by the function
-
      • 
-
    • 
-Returns: a description of the value(s) returned by the function
-
      • 
-
    • 
-Throws: any exceptions thrown by the function, and the conditions that would cause the exception
-
      • 
-
    • 
-Complexity: the time and/or space complexity of the function
-
      • 
-
    • 
-Remarks: additional semantic constraints on the function
-
      • 
-
    • 
-Error conditions: the error conditions for error codes reported by the function.
-
      • 
-
    • 
-Notes: non-normative comments about the function
-
      • 
-
    
+
    Throws: std::system_error when the effects or 
+postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
+
    
+
    Change Class condition_variable_any 30.5.2 [thread.condition.condvarany], 
+paragraph 10, as indicated:
    
+
    
 
-
    
-Whenever the Effects element specifies that the semantics of some
-function F are Equivalent to some code-sequence, then
-the various elements are interpreted as follows.  If F's
-semantics specifies a Requires element, then that requirement is
-logically imposed prior to the equivalent-to semantics.  Then,
-the semantics of the code-sequence are determined by the
-Requires, Effects, Postconditions, Returns,
-Throws, Complexity, Remarks, Error
-Conditions and Notes specified for the (one or more) function
-invocations contained in the code-sequence. The value returned from
-F is specified by F's Returns element, or
-if F has no Returns element, a non-void return from F is specified 
-by the Returns elements in code-sequence.  If
-F's semantics contains a Throws (or
-Postconditions, or Complexity) element, then that
-supersedes any occurrences of that element in the code-sequence.
-
    
+
    Throws: std::system_error when the effects or 
+postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
 
    
+
    Change Class condition_variable_any 30.5.2 [thread.condition.condvarany], 
+paragraph 16, as indicated:
    
+
    
 
+
    Throws: std::system_error when the returned value, effects, or 
+postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
+
    
 
+
    Assuming issue 859, Monotonic Clock is Conditionally Supported?, has been 
+applied to the working paper, change Change 30.5.1 [thread.condition.condvar] as 
+indicated:
    
+
    
+
    template <class Rep, class Period> 
+bool wait_for(unique_lock<mutex>& lock, 
+              const chrono::duration<Rep, Period>& rel_time);
    
+
    ...
    
 
+
    Throws: std::system_error when the effects or 
+postcondition cannot be achieved an exception is required ([thread.req.exception]).
    
+
    
 
+
    Assuming issue 859, Monotonic Clock is Conditionally Supported?, has been 
+applied to the working paper, change Change 30.5.1 [thread.condition.condvar] as 
+indicated:
    
+
    
+
    template <class Rep, class Period, class Predicate> 
+  bool wait_for(unique_lock<mutex>& lock, 
+                const chrono::duration<Rep, Period>& rel_time, 
+                Predicate pred);
    
+  
    ...
    
 
+
    Throws: std::system_error when the effects or 
+postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
+
    
 
-
    
-
    998. Smart pointer referencing its owner
    
-
    Section: 20.8.12.2.5 [unique.ptr.single.modifiers] Status: Tentatively Ready
- Submitter: Pavel Minaev Opened: 2009-02-26  Last modified: 2009-05-23
    
-
    View other active issues in [unique.ptr.single.modifiers].
    
-
    View all other issues in [unique.ptr.single.modifiers].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
-
    
-Consider the following (simplified) implementation of 
-std::auto_ptr<T>::reset(): 
-
    
+
    Assuming issue 859, Monotonic Clock is Conditionally Supported?, has been 
+applied to the working paper, change 30.5.2 [thread.condition.condvarany] as 
+indicated:
    
+
    
+
    template <class Lock, class Rep, class Period> 
+  bool wait_for(Lock& lock, const chrono::duration<Rep, Period>& rel_time);
    
+  
    ...
    
 
-
    void reset(T* newptr = 0) { 
-   if (this->ptr && this->ptr != newptr) { 
-     delete this->ptr; 
-   } 
-   this->ptr = newptr; 
-} 
-
    
+
    Throws: std::system_error when the returned value, effects or 
+postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
+
    
 
-
    
-Now consider the following code which uses the above implementation: 
-
    
+
    Assuming issue 859, Monotonic Clock is Conditionally Supported?, has been 
+applied to the working paper, change 30.5.2 [thread.condition.condvarany] as 
+indicated:
    
+
    
+
    template <class Lock, class Rep, class Period, class Predicate> 
+  bool wait_for(Lock& lock, const chrono::duration<Rep, Period>& rel_time, Predicate pred);
    
+  
    ...
    
 
-
    struct foo { 
-   std::auto_ptr<foo> ap; 
-   foo() : ap(this) {} 
-   void reset() { ap.reset(); } 
-}; 
-int main() { 
-   (new foo)->reset(); 
-} 
-
    
+
    Throws: std::system_error when the returned value, effects or 
+postcondition cannot be achieved an exception is required (30.2.2 [thread.req.exception]).
    
+
    
 
-
    
-With the above implementation of auto_ptr, this results in U.B. at the 
-point of auto_ptr::reset(). If this isn't obvious yet, let me explain 
-how this goes step by step: 
-
    
 
-
      
-
    1. 
-foo::reset() entered 
-
      2. 
-
    2. 
-auto_ptr::reset() entered 
-
      3. 
-
    3. 
-auto_ptr::reset() tries to delete foo
-
      4. 
-
    4. 
-foo::~foo() entered, tries to destruct its members 
-
      5. 
-
    5. 
-auto_ptr::~auto_ptr() executed - auto_ptr is no longer a valid object! 
-
      6. 
-
    6. 
-foo::~foo() left 
-
      7. 
-
    7. 
-auto_ptr::reset() sets its "ptr" field to 0 <- U.B.! auto_ptr
-is not a valid object here already! 
-
      8. 
-
    
 
-
    [
-Thanks to Peter Dimov who recognized the connection to unique_ptr and
-brought this to the attention of the LWG, and helped with the solution.
-]
    
 
 
+
+
    
+
    963. Various threading bugs #13
    
+
    Section: 30.3.1.5 [thread.thread.member] Status: Open
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-03-22
    
+
    View other active issues in [thread.thread.member].
    
+
    View all other issues in [thread.thread.member].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
+
    
+30.3.1.5 [thread.thread.member]:  thread::detach is required to
+throw an exception if the thread is "not a detachable thread".
+"Detachable" is never defined.
+
    
+
 
    [
 Howard adds:
 ]
    
 
 
 
    
-To fix this behavior reset must be specified such that deleting the
-pointer is the last action to be taken within reset.
+Due to a mistake on my part, 3 proposed resolutions appeared at approximately
+the same time.  They are all three noted below in the discussion.
 
    
 
 
    [
-Alisdair adds:
+Summit, proposed resolution:
 ]
    
 
 
 
    
 
    
-The example providing the rationale for LWG 998 is poor, as it relies on
-broken semantics of having two object believing they are unique owners of a
-single resource.  It should not be surprising that UB results from such
-code, and I feel no need to go out of our way to support such behaviour.
-
    
-
    
-If an example is presented that does not imply multiple ownership of a
-unique resource, I would be much more ready to accept the proposed
-resolution.
+In 30.3.1.5 [thread.thread.member] change:
 
    
-
    
-
-
    [
-Batavia (2009-05):
-]
    
 
+
    void detach();
+
    
 
    
-
    
-Howard summarizes:
-
    
-
    
-This issue has to do with circular ownership,
-and affects auto_ptr, too (but we don't really care about that).
-It is intended to spell out the order in which operations must be performed
-so as to avoid the possibility
-of undefined behavior in the self-referential case.
+
    ...
    
+
    -14- Error conditions:
    
+
      
+
    • no_such_process --  if the thread is not a valid thread.
      • 
+
    • invalid_argument -- if the thread is not a detachable joinable thread.
      • 
+
    
 
    
-
    
-Howard points to message c++std-lib-23175 for another example,
-requested by Alisdair.
-
    
-
    
-We agree with the issue and with the proposed resolution.
-Move to Tentatively Ready.
-
    
+
 
    
 
+
    
 
+
    [
+Post Summit, Jonathan Wakely adds:
+]
    
 
-
    Proposed resolution:
    
-
    
-Change 20.8.12.2.5 [unique.ptr.single.modifiers], p5 (Effects clause for reset), and p6:
-
    
 
 
    
 
    
--5- Effects: If get() == nullptr there are no effects. Otherwise get_deleter()(get()).
-Assigns p to the stored pointer, and then if the old value of the pointer is not
-equal to nullptr, calls get_deleter()(the old value of the pointer).
-[Note: The order of these operations is significant because the call to get_deleter()
-may destroy *this. -- end note]
+A thread is detachable if it is joinable. As we've defined joinable,
+we can just use that.
 
    
-
 
    
--6- Postconditions: get() == p.
-[Note: The postcondition does not hold if the call to
-get_deleter() destroys *this since this->get() is no longer a valid
-expression. -- end note]
+This corresponds to the pthreads specification, where pthread_detach
+fails if the thread is not joinable:
 
    
+
    
+EINVAL: The  implementation  has  detected  that  the value specified by
+thread does not refer to a joinable thread.
 
    
-
-
-
-
-
-
    
-
    999. Taking the address of a function
    
-
    Section: 20.8.11.1 [object.addressof] Status: Tentatively Ready
- Submitter: Peter Dimov Opened: 2009-03-09  Last modified: 2009-05-23
    
-
    View other active issues in [object.addressof].
    
-
    View all other issues in [object.addressof].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
 
    
-The same fix (reference 987) may be applied to addressof, which is also constrained to
-ObjectType. (That was why boost::ref didn't work with functions - it
-tried to apply boost::addressof and the reinterpret_cast<char&>
-implementation of addressof failed.)
+Jonathan recommends this proposed wording:
+
    
+
    
+
    
+In 30.3.1.5 [thread.thread.member] change:
 
    
 
+
    void detach();
+
    
+
    
+
    ...
    
+
    -14- Error conditions:
    
+
      
+
    • ...
      • 
+
    • invalid_argument -- not a detachable joinable thread.
      • 
+
    
+
    
 
+
    
+
    
+
    
 
 
    [
-Batavia (2009-05):
+Post Summit, Anthony Williams adds:
 ]
    
 
+
 
    
 
    
-We agree.
+This is covered by the precondition that joinable() be true.
 
    
 
    
-Move to Tentatively Ready.
+Anthony recommends this proposed wording:
 
    
-
    
-
-
 
-
    Proposed resolution:
    
+
    
 
    
-Change the synopsis in 20.8 [memory]:
+In 30.3.1.5 [thread.thread.member] change:
 
    
 
-
    template <ObjectType PointeeType T>
-  T* addressof(T& r);
-
    
+
    void detach();
+
    
+
    
+
    ...
    
+
    -14- Error conditions:
    
+
      
+
    • ...
      • 
+
    • invalid_argument -- not a detachable thread.
      • 
+
    
+
    
 
-
    
-Change 20.8.11.1 [object.addressof]:
-
    
+
    
 
-
    template <ObjectType PointeeType T>
-  T* addressof(T& r);
-
    
+
    
+
+
    
 
 
-
    Rationale:
    
-
    
-a) The occurrence of T& in the function signature auto-implies
-std::ReferentType,
-this is due to 14.11.1.2 [temp.req.impl]/4 bullet 4
-
    
+
+
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1000. adjacent_find is over-constrained
    
-
    Section: 25.3.8 [alg.adjacent.find] Status: Open
- Submitter: Chris Jefferson Opened: 2009-03-09  Last modified: 2009-03-13
    
-
    View all other issues in [alg.adjacent.find].
    
+
    964. Various threading bugs #14
    
+
    Section: 30.5.2 [thread.condition.condvarany] Status: Open
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-03-22
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-Addresses UK 296
+The requirements for the constructor for condition_variable has several
+error conditions, but the requirements for the constructor for
+condition_variable_any has none. Is this difference intentional?
 
    
 
-
    
-adjacent_find in C++03 allows an arbitrary predicate, but in C++0x
-EqualityComparable/EquivalenceRelation is required. This forbids a
-number of use cases, including:
-
    
+
    [
+Summit:
+]
    
+
+
 
    
-
-
-
-
-
-
-
-
-
-
    
-adjacent_find(begin, end, less<double>)
-
-Find the first
-place where a range is not ordered in decreasing order - in use to check
-for sorted ranges.
-
    
-adjacent_find(begin, end, DistanceBiggerThan(6) ) )
-
-Find the first
-place in a range where values differ by more than a given value - in use
-to check an algorithm which produces points in space does not generate
-points too far apart.
-
    
+Move to open, pass to Howard. If this is intentional, a note may be
+helpful. If the error conditions are to be copied from
+condition_variable, this depends on LWG 965.
 
    
 
-
    
-A number of books use predicate which are not equivalence relations in
-examples, including "Thinking in C++" and "C++ Primer".
-
    
+
    [
+Post Summit Howard adds:
+]
    
 
-
    
-Adding the requirement that the predicate is an EquivalenceRelation
-does not appear to open up any possibility for a more optimised algorithm.
-
    
 
+
    
+The original intention 
+(N2447)
+was to let the OS return whatever errors it was going to return, and for
+those to be translated into exceptions, for both
+condition_variable and condition_variable_any.  I have not
+received any complaints about specific error conditions from vendors on
+non-POSIX platforms, but such complaints would not surprise me if they surfaced.
+
    
 
 
 
    Proposed resolution:
    
-
    
-Change the definition of adjacent_find in the synopsis of 25 [algorithms]
-and 25.3.8 [alg.adjacent.find] to:
-
    
-
-
    template<ForwardIterator Iter> 
-  requires EqualityComparableHasEqualTo<Iter::value_type, Iter::value_type>
-  Iter adjacent_find(Iter first, Iter last);
-
-template<ForwardIterator Iter, EquivalenceRelationPredicate<auto, Iter::value_type, Iter::value_type> Pred> 
-  requires CopyConstructible<Pred> 
-  Iter adjacent_find(Iter first, Iter last, Pred pred);
-
    
 
 
 
 
 
 
    
-
    1001. Pointers, concepts and headers
    
-
    Section: 17 [library] Status: Review
- Submitter: Alisdair Meredith Opened: 2009-03-10  Last modified: 2009-06-16
    
-
    View other active issues in [library].
    
-
    View all other issues in [library].
    
-
    View all issues with Review status.
    
+
    966. Various threading bugs #16
    
+
    Section: 30.5.1 [thread.condition.condvar] Status: Open
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-08-01
    
+
    View other active issues in [thread.condition.condvar].
    
+
    View all other issues in [thread.condition.condvar].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
-
-
    Addresses UK 78
    
-
-
    
-Related to 1063.
-
    
-
-
    
-This is effectively an extension of LWG issue 343.
-
    
-
    
-We know there is an increasing trend (encouraged by conformance testers and
-some users) that each library header should supply no more than required to
-satisfy the synopsis in the standard.  This is typically achieved by
-breaking larger headers into smaller subsets, and judicious use of forward
-declarations.
-
    
-
    
-If we apply this policy to C++0x (per
-N2800)
-it will be very surprising for
-people using library algorithms over ranges defined by pointers that they
-must #include <iterator_concepts> for their code to compile again.  That is
-because pointers do not satisfy any of the iterator concepts without the
-concept_map supplied in this header.
-
    
-
    
-Therefore, I suggest we should require all library headers that make use of
-iterator concepts are specifically required to #include <iterator_concepts>.
-
    
 
    
-At a minimum, the list of headers would be: (assuming all are constrained by
-concepts)
+30.5.1 [thread.condition.condvar]: condition_variable::wait and
+condition_variable::wait_until both have a postcondition that lock is
+locked by the calling thread, and a throws clause that requires throwing
+an exception if this postcondition cannot be achieved. How can the
+implementation detect that this lock can never be obtained?
 
    
-
    algorithm
-array
-deque
-forward_list
-initializer_list
-iterator
-locale
-list
-map
-memory          // if 1029 is adopted
-memory_concepts
-numeric
-random
-regex
-set
-string
-tuple
-unordered_map
-unordered_set
-utility
-vector
-
    
 
 
    [
-Ganesh adds:
+Summit:
 ]
    
 
 
 
    
-
    
-The same problems exists for <memory_concepts> and
-<container_concepts>.
-
    
-
    
-In order to compile <vector> you just need the
-definitions of the concepts in <memory_concepts>, the
-concept maps defined there are not necessary. Yet, from the user point
-of view, if the concept map template for AllocatableElement are
-not in scope, <vector> is pretty useless. Same for
-<tuple> and ConstructibleWithAllocator.
-
    
-
    
-Similarly, <queue> is not very useful if the concept map
-template for QueueLikeContainer is not in scope, although the
-definition of concept alone is theoretically sufficient.
-
    
-
    
-There's a pattern here: if a concept has concept maps "attached", they
-should never be separated.
-
    
+Move to open. Requires wording. Agreed this is an issue, and the
+specification should not require detecting deadlocks.
 
    
 
 
    [
-Beman provided the proposed resolution for the May 2009 mailing. He 
-comments:
+2009-08-01 Howard provides wording.
 ]
    
 
 
 
    
-
-
    Initially I tried to specify exactly what header should include what other 
-headers. This was verbose, error prone, hard to maintain, and appeared to add 
-little value compared to just stating the general rule.
    
-
-
    
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
 
    
-Pete believes the proposed wording overconstrains implementers.
-Instead of specifying the mechanism,
-he prefers a solution that spells out what needs to be declared,
-rather than how those declarations are to be provided,
-e.g.,
+The proposed wording is inspired by the POSIX spec which says:
 
    
+
 
    
-A C++ header shall provide the names
-that are required to be defined in that header.
+
    
+
    [EINVAL]
    
+
    The value specified by cond or mutex is invalid.
    
+
    [EPERM]
    
+
    The mutex was not owned by the current thread at the time of the call.
    
+
    
 
    
+
 
    
-Bill suggests approaching the wording from a programmer's perspective.
-We may want to consider promising that certain widely-used headers
-(e.g., the concept headers) are included when needed by other headers.
-He feels, however, there is nothing broken now,
-although we may want to consider "something nicer."
-
    
-
    
-Move to Open status.
+I do not believe [EINVAL] is possible without memory corruption (which we don't
+specify).  [EPERM] is possible if this thread doesn't own the mutex, which is
+listed as a precondition.  "May" is used instead of "Shall" because not all
+OS's are POSIX.
 
    
-
-
    
-
-
    [
-2009-06-16 Beman updated the proposed resolution:
-]
    
-
-
-
    
-  
      
-    
    • The mechanism is no longer specified, as requested in Batavia.
      • 
-    
    • The footnote has been removed since it specified mechanism and also did 
-    not reflect existing practice.
      • 
-    
    • A sentence was added that makes it clear that the existing practice is 
-    permitted.
      • 
-  
    
 
    
 
 
 
 
    Proposed resolution:
    
-
    Change 17.6.4.2 [res.on.headers], Headers, paragraph 1, as indicated:
    
-
    
-  
     A C++ 
-  header shall provide definitions for any names that appear in its synopsis (3.2 [basic.def.odr]). 
-  A C++ header may include other C++ headers.[footnote] A C++ 
-  header shown in its synopsis as including other C++ headers shall provide 
-  definitions for the same names as if those other headers were included. A C++ header that uses a 
-  concept (14.10 [concept]) shall provide the definition for that concept as if it included the C++ header 
-  that defines that concept in its synopsis. The mechanism and ordering of such 
-  definitions is unspecified.
    
-
-  
    [Example: If C++ header <a> contains a concept 
-  defined in C++ header <b>, and header <b> contains a 
-  concept defined in C++ header <c>, then inclusion of <a> 
-  is equivalent to inclusion of <a>, <b>, and 
-  <c>. — end example]
    
+
    
+Change 30.5.1 [thread.condition.condvar] p12, p19 and
+30.5.2 [thread.condition.condvarany] p10, p16:
+
    
 
-  
    [footnote] C++ headers must include a C++ header that contains 
-  any needed definition (3.2).
    
+
    
+Throws: May throw std::system_error 
+
+if a precondition is not met.
+
+when the effects or postcondition
+cannot be achieved.
 
    
 
 
 
 
 
-
 
    
-
    1002. Response to UK 170
    
-
    Section: 17.6.1.2 [headers] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View all other issues in [headers].
    
-
    View all issues with Tentatively Ready status.
    
+
    967. Various threading bugs #17
    
+
    Section: 30.3.1.2 [thread.thread.constr] Status: Review
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-06-27
    
+
    View other active issues in [thread.thread.constr].
    
+
    View all other issues in [thread.thread.constr].
    
+
    View all issues with Review status.
    
 
    Discussion:
    
-
-
    Addresses UK 170
    
-
 
    
-One of goals of C++0x is to make language easier to teach and for
-'incidental' programmers. The fine-grained headers of the C++ library
-are valuable in large scale systems for managing dependencies and
-optimising build times, but overcomplicated for simple development and
-tutorials. Add additional headers to support the whole library through a
-single include statement.
+the error handling for the constructor for condition_variable
+distinguishes lack of memory from lack of other resources, but the error
+handling for the thread constructor does not. Is this difference
+intentional?
 
    
 
 
    [
-Batavia (2009-05):
+Beman has volunteered to provide proposed wording.
 ]
    
 
-
    
-We do not all agree that this is an issue,
-but we agree that if it needs solving this is the right way to do it.
-Move to Tentatively Ready.
-
    
 
 
 
    Proposed resolution:
    
-
    
-Insert a new paragraph in 17.6.1.2 [headers] between p4 and p5
-
    
+
    Change Exceptions 30.2.2 [thread.req.exception] as indicated:
    
 
    
-An additional header <std> shall have the effect of
-supplying the entire standard library.  [Note: for example, it
-might be implemented as a file with an #include statement for each of the
-headers listed in tables 13 and 14. -- end note]
+
    Some functions described in this Clause are 
+specified to throw exceptions of type system_error (19.5.5). Such exceptions 
+shall be thrown if any of the Error conditions are detected or a call to an operating system or other underlying API 
+results in an error that prevents the library function from meeting its specifications.
+[Note: See 17.6.4.10 [res.on.exception.handling] for exceptions thrown to report 
+storage allocation failures. --end 
+note]
    
+
 
    
 
+
    Change Mutex requirements 30.4.1 [thread.mutex.requirements], 
+paragraph 4, as indicated:
    
+
    
+
+
    Error conditions:
    
+  
    
+
+
      
+
    •  not_enough_memory — if there is not enough memory to construct 
+the mutex object.
      • 
 
+
    • resource_unavailable_try_again — if any native handle type 
+manipulated is not available.
      • 
 
+
    • operation_not_permitted — if the thread does not have the 
+necessary permission to change the state of the mutex object.
      • 
 
+
    • device_or_resource_busy — if any native handle type 
+manipulated is already locked.
      • 
+
+
    • invalid_argument — if any native handle type manipulated as 
+part of mutex construction is incorrect.
      • 
+
    
+  
    
+
    
+
+
    Change Class condition_variable 30.5.1 [thread.condition.condvar], 
+default constructor, as indicated:
    
+
    
+  
    condition_variable();
    
+  
    
+    
    Effects: Constructs an object of type condition_variable.
    
+    
    Throws: std::system_error when an exception is required (30.2.2 [thread.req.exception]).
    
+    
    Error conditions:
    
+    
    
+    
      
+      
    • not_enough_memory &msash; if a memory limitation prevents 
+      initialization.
      • 
+      
    •  resource_unavailable_try_again &msash; if some non-memory 
+      resource limitation prevents initialization.
      • 
+      
    •  device_or_resource_busy &msash; if attempting to initialize a 
+      previously-initialized but as of yet undestroyed condition_variable.
      • 
+    
    
+    
    
+  
    
+
    
 
-
    
-
    1003. Response to JP 23
    
-
    Section: 17.6.1.3 [compliance] Status: Review
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View other active issues in [compliance].
    
-
    View all other issues in [compliance].
    
-
    View all issues with Review status.
    
-
    Discussion:
    
 
-
    Addresses JP 23
    
 
-
    
-There is a freestanding implementation including
-<type_traits>, <array>,
-<ratio>, lately added to Table 13, C++ library headers.
-Programmers think them useful and hope that these headers are also added
-to Table 15, C++ headers for freestanding implementations, that shows
-the set of headers which a freestanding implementation shall include at
-least.
-
    
 
-
    Original proposed resolution
    
 
+
    
+
    968. Various threading bugs #18
    
+
    Section: 30.4.1 [thread.mutex.requirements] Status: Review
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-06-27
    
+
    View other active issues in [thread.mutex.requirements].
    
+
    View all other issues in [thread.mutex.requirements].
    
+
    View all issues with Review status.
    
+
    Discussion:
    
 
    
-Add <type_traits>, <array>,
-<ratio> to Table 15.
+30.4.1 [thread.mutex.requirements]: several functions are
+required to throw exceptions "if the thread does not have the necessary
+permission ...". "The necessary permission" is not defined.
 
    
 
 
    [
 Summit:
 ]
    
 
-
 
    
-
    
- The <array> header has far too many dependencies to require for a
-free-standing implementation.
-
    
-
    
-The <ratio> header would be useful, has no dependencies, but is not
-strictly necessary.
-
    
-
    
-The <type_traits> header is fundamentally a core language facility with a
-library interface, so should be supported.
-
    
-
-
    
-(it is anticipated the resolution will come via an update to paper
-N2814)
-(see also LWG 833)
-
    
+Move to open.
 
    
 
+
 
    [
-Batavia (2009-05):
+Beman has volunteered to provide proposed wording.
 ]
    
 
-
    
-Leave in Review status pending a paper on freestanding implementations
-by Martin Tasker.
-
    
 
 
 
    Proposed resolution:
    
-
    
-Add <type_traits> to Table 15.
-
    
 
 
+
    Change Exceptions 30.2.2 [thread.req.exception] as indicated:
    
+
    
+
    Some functions described in this Clause are 
+specified to throw exceptions of type system_error (19.5.5). Such exceptions 
+shall be thrown if any of the Error conditions are detected or a call to an operating system or other underlying API 
+results in an error that prevents the library function from meeting its specifications.
+[Note: See 17.6.4.10 [res.on.exception.handling] for exceptions thrown to report 
+storage allocation failures. —end 
+note]
    
 
+
    [Example:
    
 
+
    
 
+
    A function in this clause that is specified to throw exceptions of type 
+system_error and specifies Error conditions that include 
+operation_not_permitted for a thread that does not have the privilege to 
+perform the operation. During the execution of this function, an errno 
+of EPERM is reported by a POSIX API call used by the 
+implementation. Since POSIX specifies an errno of EPERM 
+when "the caller does not have the privilege to perform the operation", 
+the implementation maps EPERM  to an error_condition 
+of operation_not_permitted (19.5 [syserr]) and an exception of type 
+system_error is thrown. 
    
 
-
    
-
    1004. Response to UK 179
    
-
    Section: 17.6.3.8 [res.on.functions] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View all other issues in [res.on.functions].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
+
    
 
-
    Addresses UK 179
    
+
    —end example]
    
 
-
    
-According to the 4th bullet there is a problem if "if any replacement
-function or handler function or destructor operation throws an
-exception". There should be no problem throwing exceptions so long as
-they are caught within the function.
-
    
+
    Editorial note: For the sake of exposition, 
+the existing text above is shown with the changes proposed in issues 962 and 967. The 
+proposed additional example is independent of whether or not the 962 and 967 
+proposed resolutions are accepted.
    
 
-
    [
-Batavia (2009-05):
-]
    
+
    
+
+
    Change Mutex requirements 30.4.1 [thread.mutex.requirements], 
+paragraph 4, as indicated:
    
 
 
    
-The phrasing "throws an exception" is commonly used elsewhere
-to mean "throws or propagates an exception."
-Move to Open pending a possible more general resolution.
-
    
 
+
    — operation_not_permitted — if the thread does not have the 
+necessary permission to change the state of the mutex object privilege to perform the operation.
    
 
-
    Proposed resolution:
    
-
    
-Change the 4th bullet of 17.6.3.8 [res.on.functions], p2:
-
    
+
    
+
+
    Change Mutex requirements 30.4.1 [thread.mutex.requirements], 
+paragraph 12, as indicated:
    
 
 
    
-
      
-
    • 
-if any replacement function or handler function or destructor operation
-throws propagates an exception, unless specifically
-allowed in the applicable Required behavior: paragraph.
-
      • 
-
    
+
+
    — operation_not_permitted — if the thread does not have the 
+necessary permission to change the state of the mutex privilege to perform the operation.
    
+
 
    
 
 
@@ -26942,236 +20916,262 @@ allowed in the applicable Required behavior: paragraph.
 
 
 
    
-
    1005. Response to JP 26
    
-
    Section: 18.3.1.1 [numeric.limits] Status: Review
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-25
    
-
    View all issues with Review status.
    
+
    971. Spurious diagnostic conversion function
    
+
    Section: 19.5.2.6 [syserr.errcode.nonmembers] Status: Tentatively NAD
+ Submitter: Beman Dawes Opened: 2009-01-19  Last modified: 2009-07-22
    
+
    View all issues with Tentatively NAD status.
    
 
    Discussion:
    
-
-
    Addresses JP 26
    
-
 
    
-numeric_limits [partial specializations] does not use concept.
+Anthony Williams raised the question in c++std-lib-22987 "why is there
+std::make_error_code(std::errc)? What purpose does this serve?"
+
    
+
    
+The function make_error_code(errc e) is not required, since
+make_error_condition(errc e) is the function that is needed for errc
+conversions. make_error_code(errc e) appears to be a holdover from my
+initial confusion over the distinction between POSIX and operating
+systems that conform to the POSIX spec.
 
    
 
 
    [
-Summit:
+Post Summit:
 ]
    
 
 
 
    
-Alisdair will provide a soltion as part of treatment of axioms and LWG 902.
+Recommend Review.
 
    
 
 
    [
-Post Summit:
+Batavia (2009-05):
 ]
    
 
-
 
    
-Alisdair recommends NAD as the partial specializations are already
-constrained by requirements on the primary template.
+The designer of the facility (Christopher Kohlhoff)
+strongly disagrees that there is an issue here,
+and especially disagrees with the proposed resolution.
+Bill would prefer to be conservative and not apply this proposed resolution.
+Move to Open, and recommend strong consideration for NAD status.
 
    
 
 
    [
-Batavia (2009-05):
+2009-05-21 Beman adds:
 ]
    
 
+
 
    
-The Working Draft does not in general repeat a primary template's constraints
-in any specializations.
-Move to NAD.
+My mistake. Christopher and Bill are correct and the issue should be
+NAD. The function is needed by users.
 
    
 
 
    [
-2009-05-25 Howard adds:
+2009-07-21 Christopher Kohlhoff adds rationale for make_error_code:
 ]
    
 
 
 
    
-A c++std-lib thread starting at c++std-lib-23880 has cast doubt that NAD is the
-correct resolution of this issue.  Indeed the discussion also casts doubt that
-the current proposed wording is the correct resolution as well.  Personally I'm
-inclined to reset the status to Open.  However I'm reverting the status to 
-that which it had prior to the Batavia recommendation.  I'm setting back to Review.
+
    
+Users (and indeed library implementers) may need to use the
+errc codes in portable code. For example:
+
    
+
+
    void do_foo(error_code& ec)
+{
+#if defined(_WIN32)
+  // Windows implementation ...
+#elif defined(linux)
+  // Linux implementation ...
+#else
+  // do_foo not supported on this platform
+  ec = make_error_code(errc::not_supported);
+#endif
+}
+
    
 
    
 
 
 
    Proposed resolution:
    
 
    
-Change 18.3.1.1 [numeric.limits]:
+Change System error support 19.5 [syserr], Header <system_error>
+synopsis, as indicated:
 
    
 
-
    template<class Regular T> class numeric_limits<const T>;
-template<class Regular T> class numeric_limits<volatile T>;
-template<class Regular T> class numeric_limits<const volatile T>;
+
    error_code make_error_code(errc e);
+error_condition make_error_condition(errc e);
 
    
 
+
    
+Delete from Class error_code non-member functions
+19.5.2.6 [syserr.errcode.nonmembers]:
+
    
+
+
    error_code make_error_code(errc e);
+
    
+
    
+Returns: error_code(static_cast<int>(e),
+generic_category).
+
    
+
    
+
 
 
 
 
 
 
    
-
    1006. Response to UK 190
    
-
    Section: 18.6.1 [new.delete] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View all other issues in [new.delete].
    
-
    View all issues with Tentatively Ready status.
    
+
    974. duration<double> should not implicitly convert to duration<int>
    
+
    Section: 20.9.3.1 [time.duration.cons] Status: Open
+ Submitter: Howard Hinnant Opened: 2009-01-21  Last modified: 2009-08-01
    
+
    View all issues with Open status.
    
 
    Discussion:
    
+
    
+The following code should not compile because it involves implicit truncation
+errors (against the design philosophy of the duration library).
+
    
 
-
    Addresses UK 190
    
+
    duration<double> d(3.5);
+duration<int> i = d;  // implicit truncation, should not compile
+
    
 
 
    
-It is not entirely clear how the current specification acts in the
-presence of a garbage collected implementation.
+This intent was codified in the example implementation which drove this proposal
+but I failed to accurately translate the code into the specification in this
+regard.
 
    
 
 
    [
-Summit:
+Batavia (2009-05):
 ]
    
 
- 
 
    
-Agreed.
+
    
+We agree with the proposed resolution.
+
    
+
    
+Move to Tentatively Ready.
+
    
 
    
 
 
    [
-2009-05-09 Alisdair adds:
+2009-07 Frankfurt
 ]
    
 
 
 
    
-Proposed wording is too strict for implementations that do not support
-garbage collection.  Updated wording supplied.
+Moved from Tentatively Ready to Open only because the wording needs to be
+improved for enable_if type constraining, possibly following Robert's
+formula.
 
    
 
 
    [
-Batavia (2009-05):
+2009-08-01 Howard adds:
 ]
    
 
+
 
    
-We recommend advancing this to Tentatively Ready
-with the understanding that it will not be moved for adoption
-unless and until the proposed resolution to Core issue #853 is adopted.
+Addressed by 1177.
 
    
 
 
-
    Proposed resolution:
    
-
-
    
-(Editorial note: This wording ties into the proposed
-resolution for Core #853)
-
    
 
+
    Proposed resolution:
    
 
    
-Add paragraphs to 18.6.1.1 [new.delete.single]:
+Change 20.9.3.1 [time.duration.cons], p4:
 
    
 
-
    void operator delete(void* ptr) throw();
-void operator delete(void* ptr, const std::nothrow_t&) throw();
+
    
+
    template <class Rep2, class Period2> 
+  duration(const duration<Rep2, Period2>& d);
 
    
-
-
    [
-The second signature deletion above is editorial.
-]
    
-
-
 
    
-
    
-Requires: If an implementation has strict pointer safety
-(3.7.4.3 [basic.stc.dynamic.safety]) then ptr shall
-be a safely-derived pointer.
-
    
-
-
    -10- ...
    
+-4- Requires: treat_as_floating_point<rep>::value
+shall be true or both ratio_divide<Period2,
+period>::type::den shall be 1
+and treat_as_floating_point<Rep2>::value
+shall be false.
+Diagnostic required.
+[Note: This requirement prevents implicit truncation error when
+converting between integral-based duration types. Such a
+construction could easily lead to confusion about the value of the
+duration. -- end note]
+
    
 
    
 
-
    void operator delete(void* ptr, const std::nothrow_t&) throw();
-
    
 
-
    
-
    
-Requires: If an implementation has strict pointer safety
-(3.7.4.3 [basic.stc.dynamic.safety]) then ptr shall
-be a safely-derived pointer.
-
    
 
-
    -15- ...
    
-
    
 
-
    
 
+
    
+
    976. Class template std::stack should be movable
    
+
    Section: 23.3.5.3.1 [stack.defn] Status: Open
+ Submitter: Daniel Krügler Opened: 2009-02-01  Last modified: 2009-07-14
    
+
    View all issues with Open status.
    
+
    Discussion:
    
 
    
-Add paragraphs to 18.6.1.2 [new.delete.array]:
+The synopsis given in 23.3.5.3.1 [stack.defn] does not show up
 
    
 
-
    void operator delete[](void* ptr) throw();
-void operator delete[](void* ptr, const std::nothrow_t&) throw();
-
    
+
    requires MoveConstructible<Cont> stack(stack&&);
+requires MoveAssignable<Cont> stack& operator=(stack&&);
+
    
+
+
    
+although the other container adaptors do provide corresponding
+members.
+
    
 
 
    [
-The second signature deletion above is editorial.
+Batavia (2009-05):
 ]
    
 
-
 
    
-
    
-Requires: If an implementation has strict pointer safety
-(3.7.4.3 [basic.stc.dynamic.safety]) then ptr shall
-be a safely-derived pointer.
-
    
-
-
    -9- ...
    
+
    
+We agree with the proposed resolution.
+
    
+
    
+Move to Tentatively Ready.
+
    
 
    
 
-
    void operator delete[](void* ptr, const std::nothrow_t&) throw();
-
    
+
    [
+2009-07 Frankfurt
+]
    
 
-
    
-
    
-Requires: If an implementation has strict pointer safety
-(3.7.4.3 [basic.stc.dynamic.safety]) then ptr shall
-be a safely-derived pointer.
-
    
 
-
    -13- ...
    
+
    
+Moved from Tentatively Ready to Open only because the wording needs to be
+tweaked for concepts removal.
 
    
 
-
    
 
 
+
    Proposed resolution:
    
 
    
-Add paragraphs to 18.6.1.3 [new.delete.placement]:
+In the class stack synopsis of 23.3.5.3.1 [stack.defn] insert:
 
    
 
-
    void operator delete(void* ptr, void*) throw();
-
    
-
-
    
-
    
-Requires: If an implementation has strict pointer safety
-(3.7.4.3 [basic.stc.dynamic.safety]) then ptr shall
-be a safely-derived pointer.
-
    
-
-
    -7- ...
    
-
    
-
-
    void operator delete[](void* ptr, void*) throw();
-
    
-
-
    
-
    
-Requires: If an implementation has strict pointer safety
-(3.7.4.3 [basic.stc.dynamic.safety]) then ptr shall
-be a safely-derived pointer.
-
    
-
-
    -9- ...
    
-
    
+
    template <ObjectType T, StackLikeContainer Cont = deque<T> > 
+  requires SameType<Cont::value_type, T> 
+        && NothrowDestructible<Cont> 
+class stack { 
+public: 
+   ...
+   requires CopyConstructible<Cont> explicit stack(const Cont&); 
+   requires MoveConstructible<Cont> explicit stack(Cont&& = Cont()); 
+   requires MoveConstructible<Cont> stack(stack&&);
+   requires MoveAssignable<Cont> stack& operator=(stack&&);
+   template <class Alloc> 
+     requires Constructible<Cont, const Alloc&> 
+     explicit stack(const Alloc&);
+   ...
+};
+
    
 
-
    
+
    
+[Remark: This change should be done in sync with the resolution of
+paper
+N2819]
+
    
 
 
 
@@ -27179,208 +21179,296 @@ be a safely-derived pointer.
 
 
 
    
-
    1007. Response to JP 29
    
-
    Section: 18.8.6 [except.nested] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-13
    
-
    View other active issues in [except.nested].
    
-
    View all other issues in [except.nested].
    
+
    977. insert iterators inefficient for expensive to move types
    
+
    Section: 24.7 [insert.iterators] Status: Open
+ Submitter: Howard Hinnant Opened: 2009-02-02  Last modified: 2009-05-23
    
+
    View other active issues in [insert.iterators].
    
+
    View all other issues in [insert.iterators].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
-
-
    Addresses JP 29
    
-
 
    
-throw_with_nested does not use concept.
+The new concepts for the insert iterators mandate an extra copy when
+inserting an lvalue:
 
    
 
-
    [
-Summit:
-]
    
-
- 
+
    requires CopyConstructible<Cont::value_type>
+  back_insert_iterator<Cont>& 
+  operator=(const Cont::value_type& value);
+
    
 
    
-Agreed.
+-1- Effects: push_back(*container, Cont::value_type(value));
+
    
 
    
 
+
    
+The reason is to convert value into an rvalue because the current
+BackInsertionContainer concept only handles push_back-ing
+rvalues:
+
    
 
-
-
    Proposed resolution:
    
+
    concept BackInsertionContainer<typename C> : Container<C> { 
+  void push_back(C&, value_type&&); 
+}
+
    
 
 
    
-Alisdair initially proposed wording in
-N2619.
+Without the conversion of value to an rvalue, the assignment operator
+fails to concept check.
 
    
+
 
    
-We are awaiting an updated paper based on feedback from the San Francisco
-review.
+A solution is to modify the BackInsertionContainer concept so that
+the client can pass in the parameter type for push_back similar to
+what is already done for the OutputIterator concept:
 
    
 
+
    concept BackInsertionContainer<typename C, typename Value = C::value_type&&>
+  : Container<C> { 
+     void push_back(C&, Value); 
+}
+
    
 
+
    
+This allows the assignment operator to be adjusted appropriately:
+
    
 
+
    requires BackInsertionContainer<Cont, Cont::value_type const&> &&
+         CopyConstructible<Cont::value_type>
+  back_insert_iterator<Cont>& 
+  operator=(const Cont::value_type& value);
+
    
+
    
+-1- Effects: push_back(*container, value);
+
    
+
    
 
+
    [
+We may want to propagate this fix to other concepts such as StackLikeContainer.
+]
    
 
-
    
-
    1008. Response to JP 31
    
-
    Section: 18.8.6 [except.nested] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-13
    
-
    View other active issues in [except.nested].
    
-
    View all other issues in [except.nested].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
 
-
    Addresses JP 31
    
+
    [
+Solution and wording collaborated on by Doug and Howard.
+]
    
 
-
    
-It is difficult to understand in which case nested_exception is applied.
-
    
 
 
    [
-Summit:
+Batavia (2009-05):
 ]
    
 
- 
 
    
-Alisdair will add an example in an update to
-N2619.
+
    
+Howard notes that "these operations behaved efficiently until concepts were added."
+
    
+
    
+Alisdair is uncertain that the proposed resolution is syntactically correct.
+
    
+
    
+Move to Open, and recommend the issue be deferred until after the next
+Committee Draft is issued.
+
    
 
    
 
 
-
 
    Proposed resolution:
    
+
    
+Change 23.2.6.1 [container.concepts.free]:
+
    
 
+
    
+
    concept FrontInsertionContainer<typename C, typename Value = C::value_type&&>
+    : Container<C> { 
+  void push_front(C&, value_type&& Value); 
 
+  axiom FrontInsertion(C c, value_type Value x) { 
+    x == (push_front(c, x), front(c)); 
+  } 
+}
+
    
 
+
    ...
    
 
+
    concept BackInsertionContainer<typename C, typename Value = C::value_type&&>
+    : Container<C> { 
+  void push_back(C&, value_type&& Value); 
+}
+
    
 
-
    
-
    1009. Response to UK 251
    
-
    Section: 24.2.1 [iterator.iterators] Status: Review
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-22
    
-
    View all issues with Review status.
    
-
    Discussion:
    
-
-
    Addresses UK 251
    
+
    ...
    
 
-
    
-The post-increment operator is dangerous for a general InputIterator.
-The multi-pass guarantees that make it meaningful are defined as part of
-the ForwardIterator refinement. Any change will affect only constrained
-templates that have not yet been written, so should not break existing
-user iterators which remain free to add these operations. This change
-will also affect the generalised OutputIterator, although there is no
-percieved need for the post-increment operator in this case either.
-
    
+
    concept InsertionContainer<typename C, typename Value = C::value_type&&>
+    : Container<C> { 
+  iterator insert(C&, const_iterator, value_type&& Value); 
 
+  axiom Insertion(C c, const_iterator position, value_type Value v) { 
+    v == *insert(c, position, v); 
+  } 
+}
+
    
 
+
    
 
-
    Proposed resolution:
    
 
    
-Change 24.2.1 [iterator.iterators]:
+Change 23.2.6.2 [container.concepts.member]:
 
    
 
-
    concept Iterator<typename X> : Semiregular<X> { 
-  MoveConstructible reference = typename X::reference; 
-  MoveConstructible postincrement_result;
-
-  requires HasDereference<postincrement_result>;
+
    
+
    auto concept MemberFrontInsertionContainer<typename C, typename Value = C::value_type&&>
+    : MemberContainer<C> { 
+  void C::push_front(value_type&& Value); 
 
-  reference operator*(X&&); 
-  X& operator++(X&); 
-  postincrement_result operator++(X&, int);
+  axiom MemberFrontInsertion(C c, value_type Value x) { 
+    x == (c.push_front(x), c.front()); 
+  } 
 }
 
    
 
 
    ...
    
-
    postincrement_result operator++(X& r, int);
+
+
    auto concept MemberBackInsertionContainer<typename C, typename Value = C::value_type&&>
+    : MemberContainer<C> { 
+  void C::push_back(value_type&& Value); 
+}
 
    
 
-
    
--3- Effects: equivalent to { X tmp = r; ++r; return tmp; }.
-
    
+
    ...
    
+
+
    auto concept MemberInsertionContainer<typename C, typename Value = C::value_type&&>
+    : MemberContainer<C> { 
+  iterator C::insert(const_iterator, value_type&& Value); 
 
+  axiom MemberInsertion(C c, const_iterator position, value_type Value v) { 
+    v == *c.insert(position, v); 
+  } 
+}
+
    
 
    
 
 
    
-Change 24.2.2 [input.iterators]:
+Change 23.2.6.3 [container.concepts.maps]:
 
    
 
 
    
-
    concept InputIterator<typename X> : Iterator<X>, EqualityComparable<X> { 
-  ObjectType value_type = typename X::value_type; 
-  MoveConstructible pointer = typename X::pointer; 
+
    template <MemberFrontInsertionContainer C, typename Value = C::value_type&&> 
+concept_map FrontInsertionContainer<C, Value> { 
+  typedef Container<C>::value_type value_type;
 
-  SignedIntegralLike difference_type = typename X::difference_type; 
+  void push_front(C& c, value_type&& Value v) { c.push_front(static_cast<value_type&& Value>(v)); } 
+}
+
    
 
-  requires IntegralType<difference_type> 
-        && Convertible<reference, const value_type &>; 
-        && Convertible<pointer, const value_type*>; 
+
    ...
    
 
-  requires Convertible<HasDereference<postincrement_result>::result_type, const value_type&>;
+
    template <MemberBackInsertionContainer C, typename Value = C::value_type&&> 
+concept_map BackInsertionContainer<C, Value> { 
+  typedef Container<C>::value_type value_type;
 
-  pointer operator->(const X&); 
+  void push_back(C& c, value_type&& Value v) { c.push_back(static_cast<value_type&& Value>(v)); } 
+}
+
    
+
+
    ...
    
+
+
    template <MemberInsertionContainer C, typename Value = C::value_type&&> 
+concept_map InsertionContainer<C, Value> { 
+  typedef Container<C>::value_type value_type;
+  Container<C>::iterator insert(C& c, Container<C>::const_iterator i, value_type&& Value v) 
+  { return c.insert(i, static_cast<value_type&& Value>(v)); } 
 }
 
    
+
 
    
 
 
    
-Change 24.2.3 [output.iterators]:
+Change 24.7.1 [back.insert.iterator]:
 
    
 
-
    
-
    auto concept OutputIterator<typename X, typename Value> { 
-  requires Iterator<X>; 
+
    template <BackInsertionContainer Cont> 
+class back_insert_iterator {
+  ...
+  requires BackInsertionContainer<Cont, const Cont::value_type&>
+           CopyConstructible<Cont::value_type>
+    back_insert_iterator<Cont>& 
+      operator=(const Cont::value_type& value);
+  ...
+
    
 
-  typename reference = Iterator<X>::reference; 
-  typename postincrement_result = Iterator<X>::postincrement_result;
-  requires SameType<reference, Iterator<X>::reference> 
-        && SameType<postincrement_result, Iterator<X>::postincrement_result>
-        && Convertible<postincrement_result, const X&>
-        && HasAssign<reference, Value> 
-        && HasAssign<HasDereference<postincrement_result>::result_type, Value>;
-}
+
    
+Change 24.7.2.2 [back.insert.iter.op=]:
+
    
+
+
    
+
    requires BackInsertionContainer<Cont, const Cont::value_type&>
+         CopyConstructible<Cont::value_type>
+  back_insert_iterator<Cont>& 
+    operator=(const Cont::value_type& value);
 
    
+
    
+-1- Effects: push_back(*container, Cont::value_type(value));
+
    
 
    
 
 
    
-Change 24.2.4 [forward.iterators]:
+Change 24.7.3 [front.insert.iterator]:
 
    
 
-
    [
-See 1084 which is attempting to change this same area in a compatible
-way.
-]
    
+
    template <FrontInsertionContainer Cont> 
+class front_insert_iterator {
+  ...
+  requires FrontInsertionContainer<Cont, const Cont::value_type&>
+           CopyConstructible<Cont::value_type>
+    front_insert_iterator<Cont>& 
+      operator=(const Cont::value_type& value);
+  ...
+
    
 
+
    
+Change 24.7.4.2 [front.insert.iter.op=]:
+
    
 
 
    
-
    concept ForwardIterator<typename X> : InputIterator<X>, Regular<X> { 
-  requires Convertible<postincrement_result, const X&>;
+
    requires FrontInsertionContainer<Cont, const Cont::value_type&>
+         CopyConstructible<Cont::value_type>
+  front_insert_iterator<Cont>& 
+    operator=(const Cont::value_type& value);
+
    
+
    
+-1- Effects: push_front(*container, Cont::value_type(value));
+
    
+
    
 
-  MoveConstructible postincrement_result;
-  requires HasDereference<postincrement_result>
-        && Convertible<HasDereference<postincrement_result>::result_type, const value_type&>;
+
    
+Change 24.7.5 [insert.iterator]:
+
    
 
-  postincrement_result operator++(X&, int);
+
    template <InsertionContainer Cont> 
+class insert_iterator {
+  ...
+  requires InsertionContainer<Cont, const Cont::value_type&>
+           CopyConstructible<Cont::value_type>
+    insert_iterator<Cont>& 
+      operator=(const Cont::value_type& value);
+  ...
+
    
 
-  axiom MultiPass(X a, X b) { 
-    if (a == b) *a == *b; 
-    if (a == b) ++a == ++b; 
-  } 
-}
-
    
+
    
+Change 24.7.6.2 [insert.iter.op=]:
+
    
 
 
    
-
    -4- ...
    
-
    
-
-
    postincrement_result operator++(X& r, int);
+
    requires InsertionContainer<Cont, const Cont::value_type&>
+         CopyConstructible<Cont::value_type>
+  insert_iterator<Cont>& 
+    operator=(const Cont::value_type& value);
 
    
-
 
    
 
    
--5- Effects: equivalent to { X tmp = r; ++r; return tmp; }.
+-1- Effects:
 
    
+
    iter = insert(*container, iter, Cont::value_type(value)); 
+++iter;
+
    
 
    
-
 
    
 
 
@@ -27389,19 +21477,21 @@ way.
 
 
 
    
-
    1010. Response to UK 263
    
-
    Section: 24.2.6 [random.access.iterators] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View other active issues in [random.access.iterators].
    
-
    View all other issues in [random.access.iterators].
    
+
    978. Hashing smart pointers
    
+
    Section: 20.7.17 [unord.hash] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-02-02  Last modified: 2009-07-28
    
+
    View other active issues in [unord.hash].
    
+
    View all other issues in [unord.hash].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
-
-
    Addresses UK 263
    
-
 
    
-This requirement on operator-= would be better expressed as a default
-implementation in the concept, with a matching axiom.
+I don't see an open issue on supporting std::hash for smart pointers
+(unique_ptr and shared_ptr at least).
+
    
+
    
+It seems reasonable to at least expect support for the smart
+pointers, especially as they support comparison for use in ordered
+associative containers.
 
    
 
 
    [
@@ -27409,152 +21499,252 @@ Batavia (2009-05):
 ]
    
 
 
    
-The proposed resolution should also remove
-paragraph 5 and the declaration that precedes it.
-Further, we should provide an axiom
-that captures the desired semantics.
-This may be a broader policy to be applied.
-Move to Open.
-
    
-
-
-
    Proposed resolution:
    
 
    
-Change 24.2.6 [random.access.iterators]:
+Howard points out that the client can always supply a custom hash function.
 
    
+
    
+Alisdair replies that the smart pointer classes are highly likely
+to be frequently used as hash keys.
+
    
+
    
+Bill would prefer to be conservative.
+
    
+
    
+Alisdair mentions that this issue may also be viewed as a subissue or
+duplicate of issue 1025.
+
    
+
    
+Move to Open, and recommend the issue be deferred until after the next
+Committee Draft is issued.
+
    
+
    
 
-
    concept RandomAccessIterator<typename X> : BidirectionalIterator<X>, LessThanComparable<X> {
-  ...
-  X& operator-=(X& x, difference_type n) { return x += -n; }
-  ...
-}
-
    
-
-
-
-
-
-
-
    
-
    1011. Response to UK 271
    
-
    Section: 24.4 [iterator.operations] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View other active issues in [iterator.operations].
    
-
    View all other issues in [iterator.operations].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
+
    [
+2009-05-31 Peter adds:
+]
    
 
-
    Addresses UK 271
    
 
+
    
+
    
+Howard points out that the client can always supply a custom hash function.
+
    
 
    
-next/prev return an incremented iterator without changing the value of
-the original iterator. However, even this may invalidate an
-InputIterator. A ForwardIterator is required to guarantee the
-'multipass' property.
+Not entirely true. The client cannot supply the function that hashes the
+address of the control block (the equivalent of the old operator<, now
+proudly carrying the awkward name of 'owner_before'). Only the
+implementation can do that, not necessarily via specializing hash<>, of
+course.
+
    
+
    
+This hash function makes sense in certain situations for shared_ptr
+(when one needs to switch from set/map using ownership ordering to
+unordered_set/map) and is the only hash function that makes sense for
+weak_ptr.
 
    
+
    
 
 
    [
-Batavia (2009-05):
+2009-07-28 Alisdair provides wording.
 ]
    
 
-
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
-
    
+
 
 
 
    Proposed resolution:
    
 
    
-Change  [iterator.synopsis]:
+Add the following declarations to the synopsis of <memory>
+in 20.8 [memory]
 
    
 
-
    template <InputIterator ForwardIterator Iter> 
-  Iter next(Iter x, 
-    Iter::difference_type n = 1);
+
    // 20.8.10.X hash support
+template <class T> struct hash;
+template <class T, class D> struct hash<unique_ptr<T,D>>;
+template <class T> struct hash<shared_ptr<T>>;
 
    
 
 
    
-Change 24.4 [iterator.operations], p6:
+Add a new subclause 20.8.10.X hash support
 
    
 
-
    template <InputIterator ForwardIterator Iter> 
-  Iter next(Iter x, 
-    Iter::difference_type n = 1);
-
    
+
    
+
    
+20.8.10.X hash support [util.smartptr.hash]
+
    
+
+
    template <class T, class D> struct hash<unique_ptr<T,D>>;
+
    
+
+
    
+A partial specialization of the class template hash (20.7.17 [unord.hash]) shall be provided for instances of the
+unique_ptr template suitable for use as a key in unordered
+associative containers (23.5 [unord]) if and only if there is a
+hash specialization available for the type D::pointer.
+For an object p of type unqiue_ptr<T,D> the
+hash shall evaluate to the same value as hash<typename
+D::pointer>{}(p.get()).
+
    
+
+
    template <class T> struct hash<shared_ptr<T>>;
+
    
 
+
    
+A partial specialization of the class template hash (20.7.17 [unord.hash])
+shall be provided for instances of the shared_ptr template
+suitable for use as a key in unordered associative containers
+(23.5 [unord]). For an object p of type shared_ptr<T>
+the hash shall evaluate
+to the same value as hash<T*>{}(p.get()).
+
    
+
    
 
 
 
 
 
 
    
-
    1012. Response to UK 277
    
-
    Section: 24.5.1.2.1 [reverse.iter.cons] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View all issues with Open status.
    
+
    983. unique_ptr reference deleters should not be moved from
    
+
    Section: 20.8.9.2 [unique.ptr.single] Status: Review
+ Submitter: Howard Hinnant Opened: 2009-02-10  Last modified: 2009-05-23
    
+
    View other active issues in [unique.ptr.single].
    
+
    View all other issues in [unique.ptr.single].
    
+
    View all issues with Review status.
    
 
    Discussion:
    
+
    
+Dave brought to my attention that when a unique_ptr has a non-const reference
+type deleter, move constructing from it, even when the unique_ptr containing
+the reference is an rvalue, could have surprising results:
+
    
 
-
    Addresses UK 277
    
+
    D d(some-state);
+unique_ptr<A, D&> p(new A, d);
+unique_ptr<A, D> p2 = std::move(p);
+// has d's state changed here?
+
    
 
 
    
-The default constructor default-initializes current, rather than
-value-initializes. This means that when Iterator corresponds to a
-trivial type, the current member is left un-initialized, even when the
-user explictly requests value intialization! At this point, it is not
-safe to perform any operations on the reverse_iterator other than assign
-it a new value or destroy it. Note that this does correspond to the
-basic definition of a singular iterator.
+I agree with him.  It is the unique_ptr that is the rvalue, not the
+deleter.  When the deleter is a reference type, the unique_ptr should
+respect the "lvalueness" of the deleter.
+
    
+
+
    
+Thanks Dave.
 
    
 
 
    [
-Summit:
+Batavia (2009-05):
 ]
    
 
-
 
    
-Agree with option i.
+Seems correct, but complicated enough that we recommend moving to Review.
 
    
 
+
+
    Proposed resolution:
    
 
    
-Related issue: 408
+Change 20.8.9.2.1 [unique.ptr.single.ctor], p20-21
 
    
 
-
    [
-Batavia (2009-05):
-]
    
+
    
+
    template <class U, class E> unique_ptr(unique_ptr<U, E>&& u);
+
    
 
 
    
-We believe this should be revisited
-in conjunction with issue 408,
-which nearly duplicates this issue.
-Move to Open.
-
    
 
+
    
+-20- Requires: If D E is not a reference type,
+construction of the deleter D from an rvalue of type E
+shall be well formed and shall not throw an exception.
+
+Otherwise E is a reference type and construction of the deleter
+D from an lvalue of type E shall be well formed and
+shall not throw an exception.
+
+If D is
+a reference type, then E shall be the same type as D
+(diagnostic required). unique_ptr<U, E>::pointer shall be
+implicitly convertible to pointer. [Note: These
+requirements imply that T and U are complete types.
+-- end note]
+
    
 
-
    Proposed resolution:
    
 
    
-Change  [reverse.iter.con]:
+-21- Effects: Constructs a unique_ptr which owns the
+pointer which u owns (if any). If the deleter
+E is not a reference type, it this
+deleter is move constructed from u's deleter, otherwise
+the reference this deleter is copy constructed
+from u.'s deleter. After the construction, u no longer
+owns a pointer. [Note: The deleter constructor can be implemented
+with std::forward<DE>. -- end
+note]
 
    
 
-
    reverse_iterator();
+
    
+
    
+
+
    
+Change 20.8.9.2.3 [unique.ptr.single.asgn], p1-3
+
    
+
+
    
+
    unique_ptr& operator=(unique_ptr&& u);
 
    
 
    
--1- Effects: Default Value initializes current. Iterator
-operations applied to the resulting iterator have defined behavior if and
-only if the corresponding operations are defined on a default constructed
-iterator of type Iterator.
+
+
    
+-1- Requires: If the deleter D is not a reference type,
+Aassignment of the deleter D from an rvalue D shall not throw an exception.
+
+Otherwise the deleter D is a reference type,
+and assignment of the deleter D from an lvalue D shall not throw an exception.
+
    
+
+
    
+-2- Effects: reset(u.release()) followed by
+an move assignment from u's deleter to this deleter
+std::forward<D>(u.get_deleter()).
+
    
+
+
    
+-3- Postconditions: This unique_ptr now owns the pointer
+which u owned, and u no longer owns it. [Note: If
+D is a reference type, then the referenced lvalue deleters are
+move assigned. -- end note]
+
    
 
    
 
    
 
 
    
-Change 24.5.3.2.1 [move.iter.op.const]:
+Change 20.8.9.2.3 [unique.ptr.single.asgn], p6-7
 
    
 
-
    move_iterator();
+
    
+
    template <class U, class E> unique_ptr& operator=(unique_ptr<U, E>&& u);
 
    
 
    
--1- Effects: Constructs a move_iterator, default value
-initializing current.
+
+
    
+Requires: If the deleter E is not a reference type,
+Aassignment of the deleter D from an rvalue
+DE shall not throw an exception.
+
+Otherwise the deleter E is a reference type,
+and assignment of the deleter D from an lvalue E shall not throw an exception.
+unique_ptr<U, E>::pointer shall be implicitly convertible to pointer.
+[Note: These requirements imply that T and U>
+are complete types. -- end note]
+
    
+
+
    
+Effects: reset(u.release()) followed by
+an move assignment from u's deleter to this deleter
+std::forward<E>(u.get_deleter()).
+If either
+D or E is a reference type, then the referenced lvalue
+deleter participates in the move assignment.
+
    
+
 
    
 
    
 
@@ -27564,229 +21754,277 @@ initializing current.
 
 
 
    
-
    1013. Response to UK 305
    
-
    Section: 25.5.7 [alg.min.max] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View other active issues in [alg.min.max].
    
-
    View all other issues in [alg.min.max].
    
-
    View all issues with Tentatively Ready status.
    
+
    985. Allowing throwing move
    
+
    Section: 23.2.1 [container.requirements.general] Status: Open
+ Submitter: Rani Sharoni Opened: 2009-02-12  Last modified: 2009-05-23
    
+
    View other active issues in [container.requirements.general].
    
+
    View all other issues in [container.requirements.general].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
-
-
    Addresses UK 305
    
-
 
    
-The negative requirement on IsSameType is a hold-over from an earlier
-draught with a variadic template form of min/max algorith. It is no
-longer necessary.
+Introduction
 
    
 
-
    [
-Batavia (2009-05):
-]
    
+
    This proposal is meant to resolve potential regression of the
+N2800
+draft, see
+next section, and to relax the requirements for containers of types with
+throwing move constructors.
    
 
-
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
-
    
+
    The basic problem is that some containers operations, like push_back,
+have a strong exception safety
+guarantee (i.e. no side effects upon exception) that are not achievable when
+throwing move constructors are used since there is no way to guarantee revert
+after partial move. For such operations the implementation can at most provide
+the basic guarantee (i.e. valid but unpredictable) as it does with multi
+copying operations (e.g. range insert).
    
+
+
    For example, vector<T>::push_back() (where T has a move
+constructor) might resize the vector and move the objects to the new underlying
+buffer. If move constructor throws it might
+not be possible to recover the throwing object or to move the old objects back to
+the original buffer.
    
 
+
    The current draft is explicit by disallowing throwing move
+for some operations (e.g. vector<>::reserve) and not clear about other
+operations mentioned in 23.2.1 [container.requirements.general]/10
+(e.g. single element insert): it guarantees strong exception
+safety without explicitly disallowing a throwing move constructor.
+
    
 
-
    Proposed resolution:
    
 
    
-Change 25 [algorithms]:
+Regression
 
    
 
-
    template<class T, StrictWeakOrder<auto, T> Compare>
-  requires !SameType<T, Compare> && CopyConstructible<Compare>
-  const T& min(const T& a, const T& b, Compare comp);
-...
-template<class T, StrictWeakOrder<auto, T> Compare>
-  requires !SameType<T, Compare> && CopyConstructible<Compare>
-  const T& max(const T& a, const T& b, Compare comp);
-...
-template<class T, StrictWeakOrder<auto, T> Compare>
-  requires !SameType<T, Compare> && CopyConstructible<Compare>
-  pair<const T&, const T&> minmax(const T& a, const T& b, Compare comp);
-
    
+
    This section only refers to cases in which the contained object
+is by itself a standard container.
    
 
-
    
-Change 25.5.7 [alg.min.max], p1, p9 and p17:
-
    
+
    Move constructors of standard containers are allowed to throw and therefore
+existing operations are broken, compared with C++03, due to move optimization.
+(In fact existing implementations like Dinkumware are actually throwing).
    
 
-
    template<class T, StrictWeakOrder<auto, T> Compare>
-  requires !SameType<T, Compare> && CopyConstructible<Compare>
-  const T& min(const T& a, const T& b, Compare comp);
-...
-template<class T, StrictWeakOrder<auto, T> Compare>
-  requires !SameType<T, Compare> && CopyConstructible<Compare>
-  const T& max(const T& a, const T& b, Compare comp);
-...
-template<class T, StrictWeakOrder<auto, T> Compare>
-  requires !SameType<T, Compare> && CopyConstructible<Compare>
-  pair<const T&, const T&> minmax(const T& a, const T& b, Compare comp);
-
    
+
    For example, vector< list<int> >::reserve yields
+undefined behavior since list<int>'s move constructor is allowed to throw.
+On the other hand, the same operation has strong exception safety guarantee in
+C++03.
    
 
+
    There are few options to solve this regression:
    
+
+
      
+
    1. 
+Disallow throwing move and throwing default constructor
+
      2. 
 
+
    2. 
+Disallow throwing move but disallowing usage after move
+
      3. 
 
+
    3. 
+Special casing
+
      4. 
 
+
    4. 
+Disallow throwing move and making it optional
+
      5. 
 
+
    
 
-
    
-
    1014. Response to UK 317 and JP 74
    
-
    Section: 28.9.2 [re.regex.construct] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View all other issues in [re.regex.construct].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
+
    Option 1 is suggested by proposal
+N2815
+but it might not be applicable for existing implementations for which
+containers default constructors are throwing.
    
 
-
    Addresses UK 317 and JP 74
    
+
    Option 2 limits the usage significantly and it's error prone
+by allowing zombie objects that are nothing but destructible (e.g. no clear()
+is allowed after move). It also potentially complicates the implementation by
+introducing special state.
    
 
-
    
-UK 317:
-
    
+
    Option 3 is possible, for example, using default
+construction and swap instead of move for standard containers case. The
+implementation is also free to provide special hidden operation for non
+throwing move without forcing the user the cope with the limitation of option-2
+when using the public move.
    
 
-
    
-basic_string has both a constructor and an assignment operator that
-accepts an initializer list, basic_regex should have the same.
-
    
+
    Option 4 impact the efficiency in all use cases due to rare throwing move.
    
+
+
    The proposed wording will imply option 1 or 3 though option 2 is also
+achievable using more wording. I personally oppose to option 2 that has impact
+on usability.
    
 
 
    
-JP 74:
+Relaxation for user types
 
    
 
-
    
-basic_regx & operator= (initializer_list<T>); is not defined.
-
    
+
    Disallowing throwing move constructors in general seems very restrictive
+since, for example, common implementation of move will be default construction
++ swap so move will throw if the
+default constructor will throw. This is currently the case with the Dinkumware
+implementation of node based containers (e.g. std::list)
+though this section doesn't refer to standard types.
    
+
+
    For throwing move constructors it seem that the implementation should have
+no problems to provide the basic guarantee instead of the strong one. It's
+better to allow throwing move constructors with basic guarantee than to
+disallow it silently (compile and run), via undefined behavior.
    
+
+
    There might still be cases in which the relaxation will break existing generic
+code that assumes the strong guarantee but it's broken either way given a
+throwing move constructor since this is not a preserving optimization. 
    
 
 
    [
 Batavia (2009-05):
 ]
    
 
 
    
-UK 317 asks for both assignment and constructor,
-but the requested constructor is already present in the current Working Paper.
-We agree with the proposed resolution.
-Move to Tentatively Ready.
+
    
+Bjarne comments (referring to his draft paper):
+"I believe that my suggestion simply solves that.
+Thus, we don't need a throwing move."
+
    
+
    
+Move to Open and recommend it be deferred until after the next
+Committee Draft is issued.
+
    
 
    
 
 
 
    Proposed resolution:
    
+
 
    
-Change 28.9 [re.regex]:
+23.2.1 [container.requirements.general]  paragraph 10 add footnote:
 
    
 
-
    template <class charT,
-          class traits = regex_traits<charT> >
-class basic_regex {
-  ...
-  basic_regex& operator=(const charT* ptr);
-  basic_regex& operator=(initializer_list<charT> il);
-  template <class ST, class SA>
-    basic_regex& operator=(const basic_string<charT, ST, SA>& p);
-  ...
-};
-
    
+
    
+
    
+-10- Unless otherwise specified (see 23.1.4.1, 23.1.5.1, 23.2.2.3, and
+23.2.6.4) all container types defined in this Clause meet the following
+additional requirements:
+
    
+
      
+
    • ...
      • 
+
    
 
 
    
-Add in  28.9.2 [re.regex.construct]:
+[Note: for compatibility with C++
+2003, when "no effect" is required, standard containers should not use the
+value_type's throwing move constructor when the contained object is by itself a
+standard container. -- end note]
 
    
 
-
    
-
    
--20- ...
-
    
-
    basic_regex& operator=(initializer_list<charT> il);
-
    
-
    
--21- Effects: returns assign(il.begin(), il.end());
 
    
-
    
-
-
-
 
+
    23.2.5.1 [unord.req.except] change paragraph 2 to say: 
    
 
+
    
+
    
+-2- For unordered associative containers, if an exception is
+thrown by any operation other than the container's hash function from within an
+insert() function inserting a single element, the insert()
+function has no effect unless the exception is thrown by the contained
+object move constructor.
+
    
 
-
    
-
    1015. Response to UK 199
    
-
    Section: 20.2.1 [concept.transform] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View other active issues in [concept.transform].
    
-
    View all other issues in [concept.transform].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
+
    
+-4- For unordered associative containers, if an exception is
+thrown from within a rehash() function other than by the container's hash
+function or comparison function, the rehash() function has no effect
+unless the exception is thrown by the contained
+object move constructor.
    
 
-
    Addresses UK 199
    
+
    
 
 
    
-The requirement that programs do not supply concept_maps should
-probably be users do not supply their own concept_map
-specializations. The program will almost certainly supply
-concept_maps - the standard itself supplies a specialization
-for RvalueOf references. Note that the term program is
-defined in 3.5 [basic.link]p1 and makes no account of the
-standard library being treated differently to user written code.
+23.3.2.3 [deque.modifiers] change paragraph 2 to say:
 
    
 
-
    [
-2009-05-09 Alisdair adds:
-]
    
+
    
+-2- Remarks: If an exception is thrown other than by
+the copy constructor, move constructor
+or assignment operator of T
+there are no effects.
+If an exception is thrown by push_back() or emplace_back()
+function, that function has no effects unless the exception is thrown by
+the move constructor of T.
+
    
 
+
    
+23.3.2.3 [deque.modifiers] change paragraph 6 to say:
+
    
 
 
    
+-6- Throws: Nothing unless an exception is thrown by the copy
+constructor, move constructor or assignment operator of T.
+
    
+
 
    
-The same problem is present in the words added for the
-LvalueReference/RvalueReference concepts last meeting.
+23.3.6.2 [vector.capacity] remove paragraph 2
 
    
+
+
    
+-2- Requires: If value_type has a move constructor,
+that constructor shall not throw any exceptions.
+
    
+
 
    
-With three subsections requiring the same constraint, I'm wondering if there
-is a better way to organise this section.
-Possible 20.2.1 -> 20.2.3 belong in the fundamental concepts clause in
-14.10.4 [concept.support]?  While they can be implemented purely as a
-library feature without additional compiler support, they are pretty
-fundamental and we want the same restriction on user-concept maps as is
-mandated there.
+23.3.6.2 [vector.capacity] paragraph 3 change to say:
 
    
+
+
    
+-3- Effects: A directive that informs a vector
+of a planned change in size, so
+that it can manage the storage allocation accordingly. After reserve(),
+capacity() is greater or equal to the argument of reserve
+if reallocation happens; and equal
+to the previous value of capacity()
+otherwise. Reallocation happens at this point if and only if the current
+capacity is less than the argument of reserve().
+If an exception is thrown, there are no effects
+unless the exception is thrown by the contained object move constructor.
 
    
 
-
    [
-Batavia (2009-05):
-]
    
+
    
+23.3.6.2 [vector.capacity] paragraph 12 change to say:
+
    
 
 
    
-We agree with the issue,
-but believe the wording needs further improvement.
-We want to investigate current definitions for nomenclature such as
-"user" and "program."
-Move to Open pending the recommended investigation.
+-12- Requires: If value_type has a move constructor,
+that constructor shall not throw any exceptions.
+If an exception is thrown, there are no effects unless the exception is thrown by
+the contained object move constructor.
 
    
 
-
-
    Proposed resolution:
    
 
    
-Change 20.2.1 [concept.transform] p2:
+23.3.6.4 [vector.modifiers] change paragraph 1 to say:
 
    
 
 
    
--2- A program user shall not provide concept maps for
-any concept in 20.1.1.
+-1- Requires: If value_type has a move constructor,
+that constructor shall not throw any exceptions.
+Remarks: If an exception is thrown by push_back()
+or emplace_back() function, that function has no effect unless the
+exception is thrown by the move constructor of T.
 
    
 
 
    
-Change 20.2.2 [concept.true] p2:
+23.3.6.4 [vector.modifiers] change paragraph 2 to say:
 
    
 
 
    
--2- Requires: a program user shall not
-provide a concept map for the True concept.
+-2- Remarks: Causes reallocation if the new size is greater than
+the old capacity. If no reallocation happens, all the iterators and
+references before the insertion point remain valid. If an exception is
+thrown other than by the copy constructor, move constructor
+or assignment operator of T or by any InputIterator
+operation there are no effects.
 
    
 
 
    
-Change 20.2.3 [concept.classify] p2:
+23.3.6.4 [vector.modifiers] change paragraph 6 to say:
 
    
 
 
    
--2- Requires: a programuser shall not provide concept
-maps for any concept in this section.
+-6- Throws: Nothing unless an exception is thrown by the copy
+constructor, move constructor or assignment operator of T.
 
    
 
 
@@ -27795,176 +22033,140 @@ maps for any concept in this section.
 
 
 
    
-
    1016. Response to JP 33
    
-
    Section: 20.2.6 [concept.comparison] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
    
-
    View other active issues in [concept.comparison].
    
-
    View all other issues in [concept.comparison].
    
+
    987. reference_wrapper and function types
    
+
    Section: 20.7.5 [refwrap] Status: Open
+ Submitter: Howard Hinnant Opened: 2009-02-18  Last modified: 2009-07-14
    
+
    View all other issues in [refwrap].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
-
-
    Addresses JP 33
    
-
 
    
-LessThanComparable and EqualityComparable don't correspond to NaN. 
+The synopsis in 20.7.5 [refwrap] says:
 
    
 
-
    Original proposed resolution:
    
+
    template <ObjectType T> class reference_wrapper
+...
+
    
 
 
    
-Apply concept_map to these concepts at FloatingPointType.
+And then paragraph 3 says:
 
    
 
-
    [
-Post Summit, Alisdair adds:
-]
    
-
-
 
    
 
    
-I don't understand the proposed resolution - there is no such thing as a
-'negative' concept_map, and these concepts are auto concepts that match
-float/double etc. Also not clear how we are supposed to match values to
-concepts.
-
    
-
    
-Recommend NAD and treat as a subset of issue 902.
-
    
-
    
-
-
-
-
    Proposed resolution:
    
-
    
-Recommend NAD.
+The template instantiation reference_wrapper<T> shall be
+derived from std::unary_function<T1, R> only if the type
+T is any of the following:
 
    
 
-
-
-
-
-
    
-
    1017. Response to US 66
    
-
    Section: 20.2.11 [concept.regular] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
-
    Addresses US 66
    
+
      
+
    • 
+a function type or a pointer to function type taking one argument of
+type T1 and returning R
+
      • 
+
    
+
    
 
 
    
-Application of the Regular concept to floating-point types appears to be
-controversial (see long discussion on std-lib reflector). 
+But function types are not ObjectTypes.
 
    
 
-
    Original proposed resolution:
    
-
 
    
-State that the Regular concept does not apply to floating-point types. 
+Paragraph 4 contains the same contradiction.
 
    
 
 
    [
-Summit:
+Post Summit:
 ]
    
 
 
 
    
 
    
-Recommend that we handle the same as JP 33 / 1016.
+Jens: restricted reference to ObjectType
+
    
+
    
+Recommend Review.
 
    
 
    
 
 
    [
-Post Summit, Alisdair adds:
+Post Summit, Peter adds:
 ]
    
 
 
 
    
 
    
-Recommend Open, and review after resolution of 902 and revised axiom
-feature.
+In https://svn.boost.org/trac/boost/ticket/1846
+however Eric Niebler makes the very reasonable point that reference_wrapper<F>,
+where F is a function type, represents a reference to a function,
+a legitimate entity. So boost::ref was changed to allow it.
 
    
-
    
-
-
-
-
    Proposed resolution:
    
-
-
-
-
-
-
    
-
    1018. Response to US 70
    
-
    Section: 20.6 [meta] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
    
-
    View other active issues in [meta].
    
-
    View all other issues in [meta].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
-
    Addresses US 70
    
-
 
    
-Specifications now expressed via narrative text are more accurately and
-clearly expressed via executable code.
+https://svn.boost.org/trac/boost/browser/trunk/libs/bind/test/ref_fn_test.cpp
 
    
 
    
-Wherever concepts are available that directly match this section's type
-traits, express the traits in terms of the concepts instead of via
-narrative text. Where the type traits do not quite match the
-corresponding concepts, bring the two into alignment so as to avoid two
-nearly-identical notions.
+Therefore, I believe an alternative proposed resolution for issue 987 could simply
+allow reference_wrapper to be used with function types.
 
    
+
    
 
 
    [
-Summit:
+Post Summit, Howard adds:
 ]
    
 
 
 
    
 
    
-We think that this is a good idea, but it requires a lot of work. If someone
-submits a paper proposing specific changes, we would be happy to review it
-at the next meeting.
+I agree with Peter (and Eric).  I got this one wrong on my first try.  Here
+is code that demonstrates how easy (and useful) it is to instantiate
+reference_wrapper with a function type:
 
    
-
    
 
+
    #include <functional>
 
+template <class F>
+void test(F f);
 
-
    Proposed resolution:
    
+void f() {}
 
+int main()
+{
+    test(std::ref(f));
+}
+
    
 
+
    
+Output (link time error shows type of reference_wrapper instantiated
+with function type):
+
    
 
+
    Undefined symbols:
+  "void test<std::reference_wrapper<void ()()> >(std::reference_wrapper<void ()()>)",...
+
    
 
+
    
+I've taken the liberty of changing the proposed wording to allow function types
+and set to Open.  I'll also freely admit that I'm not positive ReferentType
+is the correct concept.
+
    
 
-
    
-
    1019. Response to UK 205
    
-
    Section: 20.6.3 [meta.help] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View other active issues in [meta.help].
    
-
    View all other issues in [meta.help].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
+
    
 
-
    Addresses UK 205
    
 
-
    
-integral_constant objects should be usable in integral-constant-expressions.
-The addition to the language of literal types and the enhanced rules for
-constant expressions make this possible.
-
    
 
 
    [
 Batavia (2009-05):
 ]
    
 
 
    
-We agree that the static data member
-ought be declared constexpr,
-but do not see a need for the proposed operator value_type().
-(A use case would be helpful.)
-Move to Open.
+
    
+Howard observed that FunctionType,
+a concept not (yet?) in the Working Paper,
+is likely the correct constraint to be applied.
+However, the proposed resolution provides an adequate approximation.
+
    
+
    
+Move to Review.
+
    
 
    
 
 
    [
@@ -27974,102 +22176,115 @@ Move to Open.
 
 
    
 
    
-The motivating case in my mind is that we can then use
-true_type and false_type as integral Boolean expressions, for example inside
-a static_assert declaration.  In that sense it is purely a matter of style.
+By constraining to PointeeType we rule out the ability for T to be a
+reference, and call in reference-collapsing.  I'm not sure if this is
+correct and intended, but would like to be sure the case was considered.
 
    
 
    
-Note that Boost has applied the non-explicit conversion operator for many
-years as it has valuable properties for extension into other metaprogramming
-libraries, such as MPL.  If additional rationale is desired I will poll the
-Boost lists for why this extension was originally applied.  I would argue
-that explicit conversion is more appropriate for 0x though.
+Is dis-allowing reference types and the
+implied reference collapsing the intended result?
 
    
 
    
 
+
    [
+2009-07 Frankfurt
+]
    
 
-
    Proposed resolution:
    
-
    
-Add to the integral_constant struct definition in 20.6.3 [meta.help]:
-
    
 
-
    template <class T, T v>
-struct integral_constant {
-  static constexpr T value = v;
-  typedef T value_type;
-  typedef integral_constant<T,v> type;
-  constexpr operator value_type() { return value; }
-};
-
    
+
    
+Moved from Review to Open only because the wording needs to be
+tweaked for concepts removal.
+
    
 
 
 
+
    Proposed resolution:
    
+
    
+Change the synopsis in 20.7 [function.objects]:
+
    
+
+
    // 20.6.5, reference_wrapper:
+template <ObjectType ReferentType T>
+  requires PointeeType<T>
+  class reference_wrapper;
 
+template <ObjectType PointeeType T>
+  reference_wrapper<T> ref(T&);
 
-
    
-
    1020. Response to UK 204
    
-
    Section: 20.6.7 [meta.trans.other] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
    
-
    View other active issues in [meta.trans.other].
    
-
    View all other issues in [meta.trans.other].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
+template <ObjectType PointeeType T>
+  reference_wrapper<const T> cref(const T&);
 
-
    Addresses UK 204
    
+template <ObjectType PointeeType T>
+  reference_wrapper<T> ref(reference_wrapper<T>);
+template <ObjectType PointeeType T>
+  reference_wrapper<const T> cref(reference_wrapper<T>);
+
    
 
 
    
-It is not possible to create a variant union based on a parameter pack
-expansion, e.g. to implement a classic discriminated union template. 
+Change the synopsis in 20.7.5 [refwrap]:
 
    
 
-
    Original proposed resolutuion:
    
+
    template <ObjectType ReferentType T>
+  requires PointeeType<T>
+  class reference_wrapper
+   ...
+
    
 
 
    
-Restore aligned_union template that was removed by LWG issue 856. 
+Change the prototypes in 20.7.5.5 [refwrap.helpers]:
 
    
 
-
    [
-Summit:
-]
    
-
-
-
    
-Agree. The need for aligned_union is compelling enough to reinstate.
-
    
-
-
    [
-Post Summit, Alisdair adds:
-]
    
-
-
-
    
-paper
-N2843
-proposes an extension to the [[align]] attribute
-that further diminishes the need for this template.  Recommend NAD.
-
    
+
    template <ObjectType PointeeType T>
+  reference_wrapper<T> ref(T&);
+...
+template <ObjectType PointeeType T>
+  reference_wrapper<const T> cref(const T&);
+...
+template <ObjectType PointeeType T>
+  reference_wrapper<T> ref(reference_wrapper<T>);
+...
+template <ObjectType PointeeType T>
+  reference_wrapper<const T> cref(reference_wrapper<T>);
+
    
 
 
 
-
    Proposed resolution:
    
+
    Rationale:
    
+
    
+a) The occurrence of T& in the function signature auto-implies
+std::ReferentType,
+this is due to 14.11.1.2 [temp.req.impl]/4 bullet 4
+
    
+
    
+b) The occurrence of the constrained template reference_wrapper<T> in
+the remaining
+signatures lets kick in 14.11.1.2 [temp.req.impl]/4 bullet 1 and adds *all* requirements of
+this template. But we need to add at least *one* requirement (and it
+was an arbitrary,
+but natural decision to require std::PointeeType here) to *activate*
+this. If we hadn't done
+this, we were in unconstrained mode!
+
    
 
 
 
 
 
 
    
-
    1021. Response to UK 211
    
-
    Section: 20.8.12.2.3 [unique.ptr.single.asgn] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View all issues with Tentatively Ready status.
    
+
    996. Move operation not well specified
    
+
    Section: 17 [library] Status: Open
+ Submitter: David Abrahams Opened: 2009-03-06  Last modified: 2009-05-23
    
+
    View other active issues in [library].
    
+
    View all other issues in [library].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
-
-
    Addresses UK 211
    
-
 
    
-The nullptr_t type was introduced to resolve the null pointer literal
-problem. It should be used for the assignemnt operator, as with the
-constructor and elsewhere through the library.
+There are lots of places in the standard where we talk about "the move
+constructor" but where we mean "the move operation," i.e.  T( move( x ) ).
+
    
+
    
+We also don't account for whether that operation modifies x or not, and
+we need to.
 
    
 
 
    [
@@ -28077,190 +22292,142 @@ Batavia (2009-05):
 ]
    
 
 
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
+Move to Open, pending proposed wording from Dave for further
+review.
 
    
 
 
 
    Proposed resolution:
    
 
    
-Change the synopsis in 20.8.12.2 [unique.ptr.single]:
-
    
-
-
    unique_ptr& operator=(unspecified-pointer-type nullptr_t);
-
    
-
-
    
-Change 20.8.12.2.3 [unique.ptr.single.asgn]:
 
    
 
-
    unique_ptr& operator=(unspecified-pointer-type nullptr_t);
-
    
-
    
-Assigns from the literal 0 or NULL. [Note: The
-unspecified-pointer-type is often implemented as a pointer to a
-private data member, avoiding many of the implicit conversion pitfalls.
--- end note]
-
    
-
    
-
 
 
 
 
 
    
-
    1023. Response to DE 22
    
-
    Section: 20.7.16.2 [func.wrap.func] Status: Tentatively NAD Editorial
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View other active issues in [func.wrap.func].
    
-
    View all other issues in [func.wrap.func].
    
-
    View all issues with Tentatively NAD Editorial status.
    
+
    999. Taking the address of a function
    
+
    Section: 20.8.8.1 [object.addressof] Status: Open
+ Submitter: Peter Dimov Opened: 2009-03-09  Last modified: 2009-07-14
    
+
    View all other issues in [object.addressof].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
-
-
    Addresses DE 22
    
-
-
    Related to issue 1114.
    
-
 
    
-The conditions for deriving from std::unary_function and
-std::binary_function are unclear: The condition would also be satisfied if
-ArgTypes were std::vector<T1>, because it (arguably)
-"contains" T1.
+The same fix (reference 987) may be applied to addressof, which is also constrained to
+ObjectType. (That was why boost::ref didn't work with functions - it
+tried to apply boost::addressof and the reinterpret_cast<char&>
+implementation of addressof failed.)
 
    
 
-
    [
-Summit:
-]
    
-
 
-
    
-Agree. std::reference_wrapper has the same structure, and we
-suggest that std::function be presented in the same way as
-std::reference_wrapper.
-
    
 
 
    [
-2009-05-09 Alisdair adds:
+Batavia (2009-05):
 ]
    
 
-
 
    
-Phrasing should be "publicly and
-unambiguously derived from" and probably back in reference_wrapper too.  Updated
-wording supplied.
+
    
+We agree.
+
    
+
    
+Move to Tentatively Ready.
+
    
 
    
 
 
    [
-Batavia (2009-05):
+2009-07 Frankfurt
 ]
    
 
+
 
    
-We agree with the proposed wording.
-Move to NAD Editorial.
+Moved from Tentatively Ready to Open only because the wording needs to be
+tweaked for concepts removal.
 
    
 
 
-
    Proposed resolution:
    
-
    
-(no changes to <functional> synopsis required)
-
    
 
+
    Proposed resolution:
    
 
    
-Change synopsis in Class template function 20.7.16.2 [func.wrap.func]:
+Change the synopsis in 20.8 [memory]:
 
    
 
-
    template<Returnable R, CopyConstructible... ArgTypes> 
-class function<R(ArgTypes...)> 
-  : public unary_function<T1, R>      // iff sizeof...(ArgTypes) == 1 and see below
-                                      // ArgTypes contains T1
-  : public binary_function<T1, T2, R> // iff sizeof...(ArgTypes) == 2 and see below
-                                      // ArgTypes contains T1 and T2
-{
-   ...
+
    template <ObjectType PointeeType T>
+  T* addressof(T& r);
 
    
 
 
    
-Add new p1/p2 before 20.7.16.2.1 [func.wrap.func.con]:
+Change 20.8.8.1 [object.addressof]:
 
    
 
-
    
-
    
-The template instantiation function<R(T1)> shall be publicly and
-unambiguously derived from 
-std::unary_function<T1,R> if and only if the template type parameter
-is a function type taking one argument of type T1 and returning R.
-
    
-
-
    
-The template instantiation function<R(T1,T2)> shall be publicly and
-unambiguously derived from 
-std::binary_function<T1,T2,R> if and only if the template type
-parameter is a function type taking two arguments of type T1 and T2 and
-returning R.
-
    
+
    template <ObjectType PointeeType T>
+  T* addressof(T& r);
+
    
 
-
    explicit function();
-
    
-
    
 
+
    Rationale:
    
+
    
+a) The occurrence of T& in the function signature auto-implies
+std::ReferentType,
+this is due to 14.11.1.2 [temp.req.impl]/4 bullet 4
+
    
 
 
 
 
 
 
    
-
    1024. Response to JP 39
    
-
    Section: 20.7.16.2 [func.wrap.func] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-05-23
    
-
    View other active issues in [func.wrap.func].
    
-
    View all other issues in [func.wrap.func].
    
-
    View all issues with Tentatively Ready status.
    
+
    1004. Response to UK 179
    
+
    Section: 17.6.3.8 [res.on.functions] Status: Ready
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-18
    
+
    View all other issues in [res.on.functions].
    
+
    View all issues with Ready status.
    
 
    Discussion:
    
 
-
    Addresses JP 39
    
+
    Addresses UK 179
    
 
 
    
-There are no requires corresponding to F of std::function.
+According to the 4th bullet there is a problem if "if any replacement
+function or handler function or destructor operation throws an
+exception". There should be no problem throwing exceptions so long as
+they are caught within the function.
 
    
 
 
    [
-2009-05-01 Daniel adds:
+Batavia (2009-05):
 ]
    
 
-
 
    
-1070 removes the second constructor.
+The phrasing "throws an exception" is commonly used elsewhere
+to mean "throws or propagates an exception."
+Move to Open pending a possible more general resolution.
 
    
 
 
    [
-Batavia (2009-05):
+2009-07 Frankfurt:
 ]
    
 
+
 
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
-If issue 1070 is accepted,
-the changes to the second constructor
-in this issue are moot.
+Replace "propagates" in the proposed resolution with the phrase "exits
+via" and move to Ready.
 
    
 
 
+
 
    Proposed resolution:
    
 
    
-Correct as follows in 20.7.16.2 [func.wrap.func] (class definition)
+Change the 4th bullet of 17.6.3.8 [res.on.functions], p2:
 
    
 
-
     template<class F, Allocator Alloc>
-   requires ConstructibleWithAllocator<F, Alloc>
-     && call=Callable<F, ArgTypes...>
-     && Convertible<call::result_type, R>
-   function(allocator_arg_t, const Alloc&, F);
- template<class F, Allocator Alloc>
-   requires ConstructibleWithAllocator<F,Alloc>
-     && call=Callable<F, ArgTypes...>
-     && Convertible<call::result_type, R>
-   function(allocator_arg_t, const Alloc&, F&&);
-
    
+
    
+
      
+
    • 
+if any replacement function or handler function or destructor operation
+throws exits via an exception, unless specifically
+allowed in the applicable Required behavior: paragraph.
+
      • 
+
    
+
    
 
 
 
@@ -28268,209 +22435,266 @@ Correct as follows in 20.7.16.2 [func.wrap.func] (class definition)
 
 
 
    
-
    1026. Response to UK 209
    
-
    Section: 20.8 [memory] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
    
-
    View other active issues in [memory].
    
-
    View all other issues in [memory].
    
+
    1008. nested_exception wording unclear
    
+
    Section: 18.8.6 [except.nested] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-04
    
+
    View other active issues in [except.nested].
    
+
    View all other issues in [except.nested].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
-
    Addresses UK 209
    
+
    Addresses JP 31
    
 
 
    
-Smart pointers cannot be used in constrained templates.
+It is difficult to understand in which case nested_exception is applied.
 
    
 
 
    [
 Summit:
 ]
    
 
-
+ 
 
    
-We look forward to a paper on this topic. We recommend no action until a
-paper is available. We understand that a paper is forthcoming.
+Alisdair will add an example in an update to
+N2619.
 
    
 
+
+
+
    Proposed resolution:
    
+
+
+
+
+
+
    
+
    1009. InputIterator post-increment dangerous
    
+
    Section: 24.2.1 [iterator.iterators] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-28
    
+
    View all issues with Open status.
    
+
    Discussion:
    
+
+
    Addresses UK 251
    
+
+
    
+The post-increment operator is dangerous for a general InputIterator.
+The multi-pass guarantees that make it meaningful are defined as part of
+the ForwardIterator refinement. Any change will affect only constrained
+templates that have not yet been written, so should not break existing
+user iterators which remain free to add these operations. This change
+will also affect the generalised OutputIterator, although there is no
+percieved need for the post-increment operator in this case either.
+
    
+
 
    [
-Peter Dimov adds:
+2009-07-28 Alisdair adds:
 ]
    
 
 
 
    
-shared_ptr<T> and weak_ptr<T> support all
-types T for which T* is valid. In other words, a
-possible (partial) resolution is to change class T to
-PointeeType T for shared_ptr, weak_ptr and
-possibly enable_shared_from_this.
+We still think the issue is relevant, but needs totally rewording in
+non-concept language.  We would like to see the issue retained as Open,
+rather than deferred as NAD Concepts.  Review status is no longer
+appropriate.
 
    
 
 
 
 
    Proposed resolution:
    
+
    
+Change 24.2.1 [iterator.iterators]:
+
    
 
+
    concept Iterator<typename X> : Semiregular<X> { 
+  MoveConstructible reference = typename X::reference; 
+  MoveConstructible postincrement_result;
 
+  requires HasDereference<postincrement_result>;
 
+  reference operator*(X&&); 
+  X& operator++(X&); 
+  postincrement_result operator++(X&, int);
+}
+
    
 
+
    ...
    
+
    postincrement_result operator++(X& r, int);
+
    
 
-
    
-
    1027. Response to UK 213
    
-
    Section: 20.8.6 [default.allocator] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-13
    
-
    View all issues with Open status.
    
-
    Discussion:
    
+
    
+-3- Effects: equivalent to { X tmp = r; ++r; return tmp; }.
+
    
 
-
    Addresses UK 213
    
+
    
 
 
    
-std::allocator should be constrained to simplify its use on constrained
-contexts. This library component models allocation from free store via the
-new operator so choose constraints to 
-match. The Allocator concept allows for a wider variety of allocators that
-users may choose to supply if their allocation model does not require
-operator new, without impacting the 
-requirements of this template. 
+Change 24.2.2 [input.iterators]:
 
    
 
+
    
+
    concept InputIterator<typename X> : Iterator<X>, EqualityComparable<X> { 
+  ObjectType value_type = typename X::value_type; 
+  MoveConstructible pointer = typename X::pointer; 
+
+  SignedIntegralLike difference_type = typename X::difference_type; 
+
+  requires IntegralType<difference_type> 
+        && Convertible<reference, const value_type &>; 
+        && Convertible<pointer, const value_type*>; 
+
+  requires Convertible<HasDereference<postincrement_result>::result_type, const value_type&>;
+
+  pointer operator->(const X&); 
+}
+
    
+
    
+
 
    
-Suggested direction:
+Change 24.2.3 [output.iterators]:
 
    
+
+
    
+
    auto concept OutputIterator<typename X, typename Value> { 
+  requires Iterator<X>; 
+
+  typename reference = Iterator<X>::reference; 
+  typename postincrement_result = Iterator<X>::postincrement_result;
+  requires SameType<reference, Iterator<X>::reference> 
+        && SameType<postincrement_result, Iterator<X>::postincrement_result>
+        && Convertible<postincrement_result, const X&>
+        && HasAssign<reference, Value> 
+        && HasAssign<HasDereference<postincrement_result>::result_type, Value>;
+}
+
    
+
    
+
 
    
-The primary allocator template should be constrained to require
-ObjectType<T> and FreeStoreAllocatable<T>.
-Further operations to be constrained as required.
+Change 24.2.4 [forward.iterators]:
 
    
 
 
    [
-Summit:
+See 1084 which is attempting to change this same area in a compatible
+way.
 ]
    
 
 
 
    
-Agree as stated. A future paper will address additional related issues.
+
    concept ForwardIterator<typename X> : InputIterator<X>, Regular<X> { 
+  requires Convertible<postincrement_result, const X&>;
+
+  MoveConstructible postincrement_result;
+  requires HasDereference<postincrement_result>
+        && Convertible<HasDereference<postincrement_result>::result_type, const value_type&>;
+
+  postincrement_result operator++(X&, int);
+
+  axiom MultiPass(X a, X b) { 
+    if (a == b) *a == *b; 
+    if (a == b) ++a == ++b; 
+  } 
+}
+
    
+
+
    
+
    -4- ...
    
 
    
 
+
    postincrement_result operator++(X& r, int);
+
    
+
+
    
+
    
+-5- Effects: equivalent to { X tmp = r; ++r; return tmp; }.
+
    
+
    
 
+
    
 
-
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1028. Response to UK 214
    
-
    Section: 20.8.8 [storage.iterator] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-15
    
+
    1011. next/prev wrong iterator type
    
+
    Section: 24.4 [iterator.operations] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-14
    
+
    View other active issues in [iterator.operations].
    
+
    View all other issues in [iterator.operations].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
-
    Addresses UK 214
    
+
    Addresses UK 271
    
 
 
    
-raw_storage_iterator needs constraining as an iterator adaptor to be safely
-used in constrained templates 
+next/prev return an incremented iterator without changing the value of
+the original iterator. However, even this may invalidate an
+InputIterator. A ForwardIterator is required to guarantee the
+'multipass' property.
 
    
 
 
    [
-Summit:
+Batavia (2009-05):
 ]
    
 
-
 
    
-We look forward to a paper on this topic. We recommend no action until a
-paper is available.
+We agree with the proposed resolution.
+Move to Tentatively Ready.
 
    
 
 
    [
-Post Summit Alisdair provided wording and rationale.
+2009-07 Frankfurt
 ]
    
 
 
+
    
+Moved from Tentatively Ready to Open only because the wording needs to be
+tweaked for concepts removal.
+
    
+
 
 
 
    Proposed resolution:
    
 
    
-20.8 [memory] p2
-
    
-
    
-Update the synopsis for <memory>
+Change  [iterator.synopsis]:
 
    
-
    // 20.7.8, raw storage iterator:
-template <class ForwardIterator OutputIterator, class ObjectType T> 
-  requires OutputIterator< OutIter, T >
-    class raw_storage_iterator;
 
-template <ForwardIterator OutIter, ObjectType T> 
-  requires OutputIterator< OutIter, T >
-  concept_map Iterator<raw_storage_iterator< OutIter, T > > { }
+
    template <InputIterator ForwardIterator Iter> 
+  Iter next(Iter x, 
+    Iter::difference_type n = 1);
 
    
 
-
-
    
-20.8.8 [storage.iterator] p1
-
    
 
    
-Replace class template definition with:
+Change 24.4 [iterator.operations], p6:
 
    
-
    namespace std { 
-  template <class ForwardIterator OutputIterator, class ObjectType T> 
-    requires OutputIterator< OutIter, T >
-  class raw_storage_iterator 
-    : public iterator<output_iterator_tag,void,void,void,void> { 
-  public: 
-    explicit raw_storage_iterator(OutputIterator x); 
-
-    raw_storage_iterator<OutputIterator,T>& operator*(); 
-    raw_storage_iterator<OutputIterator,T>& operator=(const T& element); 
-    raw_storage_iterator<OutputIterator,T>& operator++(); 
-    raw_storage_iterator<OutputIterator,T> operator++(int); 
-  }; 
 
-  template <ForwardIterator OutIter, ObjectType T> 
-    requires OutputIterator< OutIter, T >
-    concept_map Iterator<raw_storage_iterator< OutIter, T > > { }
-}
+
    template <InputIterator ForwardIterator Iter> 
+  Iter next(Iter x, 
+    Iter::difference_type n = 1);
 
    
 
 
-
    Rationale:
    
-
    
-raw_storage_iterator has to adapt a ForwardIterator,
-rather than just an InputIterator for two reasons:
-
    
-
-
      
-
    1. 
-The initial iterator passed by value is expected to remain valid,
-pointing to the initialized region of memory.
-
      2. 
-
    2. 
-to avoid breaking the declaration of post-increment operator which would
-require some kind of proxy formulation to support generalised InputIterators.
-
      3. 
-
    
-
-
 
 
 
 
 
    
-
    1029. Response to UK 210
    
-
    Section: 20.8.11 [specialized.algorithms] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-15
    
-
    View all other issues in [specialized.algorithms].
    
-
    View all issues with Open status.
    
+
    1012. reverse_iterator default ctor should value initialize
    
+
    Section: 24.5.1.2.1 [reverse.iter.cons] Status: Tentatively Ready
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-18
    
+
    View all issues with Tentatively Ready status.
    
 
    Discussion:
    
 
-
    Addresses UK 210
    
-
-
    Related to 582
    
+
    Addresses UK 277
    
 
 
    
-Specialized algorithms for memory managenment need requirements to be
-easily usable in constrained templates.
+The default constructor default-initializes current, rather than
+value-initializes. This means that when Iterator corresponds to a
+trivial type, the current member is left un-initialized, even when the
+user explictly requests value intialization! At this point, it is not
+safe to perform any operations on the reverse_iterator other than assign
+it a new value or destroy it. Note that this does correspond to the
+basic definition of a singular iterator.
 
    
 
 
    [
@@ -28479,206 +22703,236 @@ Summit:
 
 
 
    
-We look forward to a paper on this topic. We recommend no action until a
-paper is available.
+Agree with option i.
 
    
 
+
    
+Related issue: 408
+
    
+
 
    [
-Post Summit Alisdair provided wording.
+Batavia (2009-05):
 ]
    
 
+
    
+We believe this should be revisited
+in conjunction with issue 408,
+which nearly duplicates this issue.
+Move to Open.
+
    
 
 
    [
-Post Summit:
+2009-07 post-Frankfurt:
 ]
    
 
 
 
    
 
    
-Daniel adds:
+Change "constructed" to "initialized" in two places in the proposed resolution.
 
    
-
-
    
-
      
-
    1. 
-I suggest Size should require IntegralLike and not UnsignedIntegralLike,
-because otherwise simple int-literals could not be provided as arguments
-and it would conflict with other algorithms that only require IntegralLike.
-
      2. 
-
    2. 
 
      
-The current for-loop-test relies on evaluation in boolean context which is
-not provided by ArithmeticLike and it's refinements. I propose to change the
-corresponding for-loop-headers to:
+Move to Tentatively Ready.
 
      
-
        
-
      1. 
-for uninitialized_copy_n: for ( ; n > Size(0); ++result, ++first, --n) {
-
        2. 
-
      2. 
-for uninitialized_fill_n: for (; n > Size(0); ++first, --n) {
-
        3. 
-
      
-
      3. 
-
    
 
    
 
+
+
+
    Proposed resolution:
    
 
    
-Alisdair adds:
+Change  [reverse.iter.con]:
 
    
+
+
    reverse_iterator();
+
    
 
    
-For the record I agree with Daniel's suggestion.
+-1- Effects: Default Value initializes current. Iterator
+operations applied to the resulting iterator have defined behavior if and
+only if the corresponding operations are defined on a default constructed
+value initialized
+iterator of type Iterator.
+
    
 
    
 
+
    
+Change 24.5.2.2.1 [move.iter.op.const]:
+
    
+
+
    move_iterator();
+
    
+
    
+-1- Effects: Constructs a move_iterator, default value
+initializing current.
+Iterator
+operations applied to the resulting iterator have defined behavior if and
+only if the corresponding operations are defined on a
+value initialized
+iterator of type Iterator.
+
    
 
    
 
 
 
-
    Proposed resolution:
    
-
    
-20.8 [memory] p2
-
    
-
    
-Update the synopsis for <memory>
-
    
-
    template <class InputIterator InIter,
-         class ForwardIterator OutputIterator<auto, InIter::reference> OutIter> 
-   requires ForwardIterator<OutIter>
-   ForwardIterator OutIter
-   uninitialized_copy(InputIterator InIter first, InputIterator InIter last, 
-                      ForwardIterator OutIter result);
 
-template <class InputIterator InIter,
-          class IntegralLike Size,
-          class ForwardIterator OutputIterator<auto, InIter::reference> OutIter> 
-  requires ForwardIterator<OutIter>
-  ForwardIterator OutIter
-  uninitialized_copy_n(InputIterator InIter first, Size n, 
-                       ForwardIterator OutIter result);
 
-template <class ForwardIterator Iter, class ObjectType T>
-  requires Constructible< Iter::value_type, const T& >
-  void uninitialized_fill(ForwardIterator Iter first, ForwardIterator Iter last, 
-                          const T& x);
 
-template <class ForwardIterator Iter, class IntegralLike Size, class ObjectType T> 
-  requires Constructible< Iter::value_type, const T& >
-  void
-  uninitialized_fill_n(ForwardIterator Iter first, Size n, const T& x);
-
    
+
    
+
    1019. Response to UK 205
    
+
    Section: 20.6.3 [meta.help] Status: Tentatively Ready
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-18
    
+
    View all other issues in [meta.help].
    
+
    View all issues with Tentatively Ready status.
    
+
    Discussion:
    
 
-
    
-Update as follows:
-
    
+
    Addresses UK 205
    
 
 
    
-uninitialized_copy 20.8.11.2 [uninitialized.copy]
+integral_constant objects should be usable in integral-constant-expressions.
+The addition to the language of literal types and the enhanced rules for
+constant expressions make this possible.
 
    
 
-
    template <class InputIterator InIter,
-         class ForwardIterator OutputIterator<auto, InIter::reference> OutIter> 
-   requires ForwardIterator<OutIter>
-   ForwardIterator OutIter
-   uninitialized_copy(InputIterator InIter first, InputIterator InIter last, 
-                      ForwardIterator OutIter result);
-
    
+
    [
+Batavia (2009-05):
+]
    
+
+
    
+We agree that the static data member
+ought be declared constexpr,
+but do not see a need for the proposed operator value_type().
+(A use case would be helpful.)
+Move to Open.
+
    
+
+
    [
+2009-05-23 Alisdair adds:
+]
    
+
 
 
    
 
    
--1- Effects:
+The motivating case in my mind is that we can then use
+true_type and false_type as integral Boolean expressions, for example inside
+a static_assert declaration.  In that sense it is purely a matter of style.
 
    
-
    for (; first != last; ++result, ++first)  {
-   new (static_cast<void*>(&*result))
-       typename iterator_traits<ForwardIterator> OutIter::value_type(*first);
-}
-
    
-
 
    
--2- Returns: result
+Note that Boost has applied the non-explicit conversion operator for many
+years as it has valuable properties for extension into other metaprogramming
+libraries, such as MPL.  If additional rationale is desired I will poll the
+Boost lists for why this extension was originally applied.  I would argue
+that explicit conversion is more appropriate for 0x though.
 
    
-
 
    
 
-
    template <class InputIterator InIter,
-          class IntegralLike Size,
-          class ForwardIterator OutputIterator<auto, InIter::reference> OutIter> 
-  requires ForwardIterator<OutIter>
-  ForwardIterator OutIter
-  uninitialized_copy_n(InputIterator InIter first, Size n, 
-                       ForwardIterator OutIter result);
-
    
+
    [
+2009-07-04 Howard adds:
+]
    
+
 
 
    
 
    
--3- Effects:
+Here's a use case which demonstrates the syntactic niceness which Alisdair describes:
 
    
-
    for ( ; n > Size(0); ++result, ++first, --n) {
-   new (static_cast<void*>(&*result))
-       typename iterator_traits<ForwardIterator> OutIter::value_type(*first);
+
+
    #define requires(...) class = typename std::enable_if<(__VA_ARGS__)>::type
+
+template <class T, class U,
+    requires(!is_lvalue_reference<T>() ||
+              is_lvalue_reference<T>() && is_lvalue_reference<U>()),
+    requires(is_same<typename base_type<T>::type,
+                     typename base_type<U>::type>)>
+inline
+T&&
+forward(U&& t)
+{
+    return static_cast<T&&>(t);
 }
 
    
-
    
--4- Returns: result
-
    
 
    
 
+
    [
+2009-07 post-Frankfurt:
+]
    
+
+
+
    
+Move to Tentatively Ready.
 
    
 
 
+
+
    Proposed resolution:
    
 
    
-uninitialized_fill 20.8.11.3 [uninitialized.fill]
+Add to the integral_constant struct definition in 20.6.3 [meta.help]:
 
    
 
-
    template <class ForwardIterator Iter, class ObjectType T>
-  requires Constructible< Iter::value_type, const T& >
-  void uninitialized_fill(ForwardIterator Iter first, ForwardIterator Iter last, 
-                          const T& x);
-
    
+
    template <class T, T v>
+struct integral_constant {
+  static constexpr T value = v;
+  typedef T value_type;
+  typedef integral_constant<T,v> type;
+  constexpr operator value_type() { return value; }
+};
+
    
+
+
+
+
+
+
    
+
    1020. Response to UK 204
    
+
    Section: 20.6.7 [meta.trans.other] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
    
+
    View other active issues in [meta.trans.other].
    
+
    View all other issues in [meta.trans.other].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
+
+
    Addresses UK 204
    
 
-
    
 
    
--1- Effects:
+It is not possible to create a variant union based on a parameter pack
+expansion, e.g. to implement a classic discriminated union template. 
 
    
-
    for (; first != last; ++first) {
-   new ( static_cast<void*>( &*first) ) 
-       typename iterator_traits<ForwardIterator> Iter::value_type(x);
-}
-
    
-
    
-
    
 
+
    Original proposed resolutuion:
    
 
 
    
-uninitialized_fill_n 20.8.11.4 [uninitialized.fill.n]
+Restore aligned_union template that was removed by LWG issue 856. 
 
    
 
-
    template <class ForwardIterator Iter, class IntegralLike Size, class ObjectType T> 
-  requires Constructible< Iter::value_type, const T& >
-  void
-  uninitialized_fill_n(ForwardIterator Iter first, Size n, const T& x);
-
    
+
    [
+Summit:
+]
    
+
 
 
    
-
    
--1- Effects:
-
    
-
    for (; n-- > Size(0); ++first, --n) {
-   new ( static_cast<void*>( &*first) ) 
-       typename iterator_traits<ForwardIterator> Iter::value_type(x);
-}
-
    
+Agree. The need for aligned_union is compelling enough to reinstate.
 
    
+
+
    [
+Post Summit, Alisdair adds:
+]
    
+
+
+
    
+paper
+N2843
+proposes an extension to the [[align]] attribute
+that further diminishes the need for this template.  Recommend NAD.
 
    
 
 
 
+
    Proposed resolution:
    
+
+
 
 
 
 
    
 
    1030. Response to JP 44
    
-
    Section: 20.8.13.6 [util.smartptr.shared.atomic] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
    
+
    Section: 20.8.10.6 [util.smartptr.shared.atomic] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-18
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
@@ -28704,6 +22958,24 @@ Agree. All of the functions need a requirement that p (or
 v) is a pointer to a valid object.
 
    
 
+
    [
+2009-07 post-Frankfurt:
+]
    
+
+
+
    
+
    
+Lawrence explained that these signatures match the regular atomics. The
+regular atomics must not use references because these signatures are
+shared with C. The decision to pass shared_ptrs by pointer rather than
+by reference was deliberate and was motivated by the principle of least
+surprise.
+
    
+
    
+Lawrence to write wording that requires that the pointers not be null.
+
    
+
    
+
 
 
 
    Proposed resolution:
    
@@ -28714,11 +22986,11 @@ Agree. All of the functions need a requirement that p (or
 
 
    
 
    1031. Response to US 78
    
-
    Section: 20.8.13.2 [util.smartptr.shared] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
    
+
    Section: 20.8.10.2 [util.smartptr.shared] Status: Tentatively NAD Future
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-26
    
 
    View other active issues in [util.smartptr.shared].
    
 
    View all other issues in [util.smartptr.shared].
    
-
    View all issues with Open status.
    
+
    View all issues with Tentatively NAD Future status.
    
 
    Discussion:
    
 
 
    Addresses US 78
    
@@ -28749,45 +23021,71 @@ This is basically a request for shared_ptr<>::release in
 disguise, with all the associated problems. Not a good idea.
 
    
 
+
    [
+2009-07 post-Frankfurt:
+]
    
 
 
-
    Proposed resolution:
    
-
-
-
-
-
-
    
-
    1032. Response to JP 45
    
-
    Section: 20.9 [time] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
    
-
    View all other issues in [time].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
-
    Addresses JP 45
    
-
+
    
 
    
-Rep, Period, Clock and Duration
-don't correspond to concept.
+The rationale for the omission of a release() member function from shared_ptr is given in:
+http://www.boost.org/doc/libs/1_39_0/libs/smart_ptr/shared_ptr.htm
 
    
-
    template <class Rep, class Period = ratio<1>> class duration; 
-template <class Clock, class Duration = typename Clock::duration> class time_point; 
-
    
 
    
-Make concept for Rep, Period, Clock and Duration.
-Fix 20.9 [time] and wait_until
-and wait_for's template parameter at 30 [thread]. 
+The implementation of such a member is non-trivial (and maybe
+impossible), because it would need to account for the deleter.
 
    
+
    
 
 
    [
-Summit:
+2009-07-26 Howard sets to Tentatively NAD Future.
 ]
    
 
 
 
    
-We agree that this section needs concepts. We look forward to a paper on
-this topic. We recommend no action until a paper is available.
+
    
+I took an online poll and got 3 votes for NAD and 3 for NAD Future.  Personally
+I prefer NAD Future as this does refer to an extension that could conceivably be
+considered beyond C++0X.
+
    
+
+
    
+However such an extension would need to solve a couple of problems:
+
    
+
+
      
+
    1. What is the interface for such a conversion when the shared_ptr does
+not have unique ownership?  Throw an exception?  Create a null unique_ptr?
+Undefined behavior?
+
      2. 
+
+
    2. 
+
      
+How does one handle custom deleters given to the shared_ptr constructor?
+
      
+
      
+I do not believe it is possible to implement a general answer to this question.
+The shared_ptr deleter is a run time (or construction time) characteristic.
+The unique_ptr deleter is a compile time characteristic.  In general one
+can not know to what type of unqiue_ptr you are converting to.
+
      
+
      
+One answer is for the user of the conversion to specify the deleter type and perhaps
+throw an exception if the specification turns out to be incorrect.
+
      
+
      
+Another answer is for the conversion to only be valid when the underlying deleter
+is default_delete.  We would probalby need to specify that this is indeed the
+underlying deleter of a shared_ptr when a custom deleter is not given in
+the constructor.
+
      
+
      3. 
+
    
+
+
    
+At any rate, there are non-trivial design issues which would need to be implemented
+and tested in the field for usability prior to standardization.
+
    
 
    
 
 
@@ -28890,7 +23188,7 @@ Move to Open.
 
    
 
    1034. Response to UK 222
    
 
    Section: 23.2.1 [container.requirements.general] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-03-12
    
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
    
 
    View other active issues in [container.requirements.general].
    
 
    View all other issues in [container.requirements.general].
    
 
    View all issues with Open status.
    
@@ -28935,343 +23233,47 @@ Summit:
 Agree in principle.
 
    
 
-
-
-
    Proposed resolution:
    
-
-
-
-
-
-
    
-
    1035. Response to UK 226
    
-
    Section: 23.2.1 [container.requirements.general] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-02
    
-
    View other active issues in [container.requirements.general].
    
-
    View all other issues in [container.requirements.general].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
-
    Addresses UK 226
    
-
-
    
-<array> must be added to this list. In particular it
-doesn't satisfy: - no swap() function invalidates any
-references, pointers, or iterators referring to the elements of the
-containers being swapped. and probably doesn't satisfy: - no
-swap() function throws an exception.
-
    
-
    
-If <array> remains a container, this will have to also
-reference array, which will then have to say which of these
-points it satisfies.
-
    
-
-
    [
-Summit:
-]
    
-
-
-
    
-Agree. The proposed resolution is incomplete. Further work required.
-
    
-
-
    [
-2009-05-01 Daniel adds:
-]
    
-
-
-
    
-Issue 1099 also suggests
-adding move constructor to this.
-
    
-
-
-
-
    Proposed resolution:
    
-
-
-
-
-
-
    
-
    1036. Response to UK 231
    
-
    Section: 23.2.3 [sequence.reqmts] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-03-12
    
-
    View other active issues in [sequence.reqmts].
    
-
    View all other issues in [sequence.reqmts].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
-
    Addresses UK 231
    
-
-
    
-p9-p11 are redundant now that Concepts define what it means to be an
-Iterator and guide overload resolution accordingly. 
-
    
-
-
    [
-Summit:
-]
    
-
-
-
    
-Agree with issue and change to 23.2.3 [sequence.reqmts]. The
-changes required to 21 [strings] will be part of the general
-concept support for that clause.
-
    
-
-
-
-
    Proposed resolution:
    
-
    
-Strike 23.2.3 [sequence.reqmts]p9-11. Make sure std::basic_string
-has constraints similar to
-std::vector to meet this old guarantee. 
-
    
-
-
-
-
-
-
    
-
    1037. Response to UK 232
    
-
    Section: 23.2.3 [sequence.reqmts] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-23
    
-
    View other active issues in [sequence.reqmts].
    
-
    View all other issues in [sequence.reqmts].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
-
-
    Addresses UK 232
    
-
-
    
-match_results may follow the requirements but is not listed a general
-purpose library container.
-
    
-
-
    
-Remove reference to match_results against a[n] operation.
-
    
-
-
    [
-Summit:
-]
    
-
-
-
    
-Agree. operator[] is defined elsewhere.
-
    
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
-
    
-
-
-
    Proposed resolution:
    
-
    
-In 23.2.3 [sequence.reqmts] Table 84, remove reference to
-match_results in the row describing the a[n] operation.
-
    
-
-
-
-
-
-
    
-
    1038. Response to UK 233
    
-
    Section: 23.2.3 [sequence.reqmts] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-23
    
-
    View other active issues in [sequence.reqmts].
    
-
    View all other issues in [sequence.reqmts].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
-
-
    Addresses UK 233
    
-
-
    
-Table 84 is missing references to several new container types.
-
    
-
-
    [
-Summit:
-]
    
-
-
-
    
-Agree.
-
    
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
-
    
-
-
-
    Proposed resolution:
    
-
    
-In 23.2.3 [sequence.reqmts] Table 84, Add reference to listed
-containers to the following rows:
-
    
-
-
    
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
    Table 84 -- Optional sequence container operations
    ExpressionReturn typeOperational semanticsContainer
    a.front()......vector, list, deque, basic_string, array, forward_list
    a.back()......vector, list, deque, basic_string, array
    a.emplace_front(args)......list, deque, forward_list
    a.push_front(t)......list, deque, forward_list
    a.push_front(rv)......list, deque, forward_list
    a.pop_front()......list, deque, forward_list
    a[n]......vector, deque, basic_string, array
    a.at(n)......vector, deque, basic_string, array
    
-
    
-
-
-
-
-
-
    
-
    1039. Response to UK 234
    
-
    Section: 23.2.3 [sequence.reqmts] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-23
    
-
    View other active issues in [sequence.reqmts].
    
-
    View all other issues in [sequence.reqmts].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
-
-
    Addresses UK 234
    
-
-
    
-The reference to iterator in semantics for back should
-also allow for const_iterator when called on a const-qualified
-container. This would be ugly to specify in the 03 standard, but is
-quite easy with the addition of auto in this new standard.
-
    
-
-
    [
-Summit:
-]
    
-
-
-
    
-Agree.
-
    
-
 
    [
-Batavia (2009-05):
+2009-07 post-Frankfurt:
 ]
    
 
-
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
-
    
-
-
-
    Proposed resolution:
    
-
    
-In 23.2.3 [sequence.reqmts] Table 84, replace iterator with auto in semantics for back:
-
    
 
 
    
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
    Table 84 -- Optional sequence container operations
    ExpressionReturn typeOperational semanticsContainer
    a.back()reference; const_reference for constant a{ iterator auto tmp = a.end();
    --tmp;
    return *tmp; }    		vector, list, deque, basic_string
    
+We agree in principle, but we have a timetable. This group feels that
+the issue should be closed as NAD unless a proposed resolution is
+submitted prior to the March 2010 meeting.
 
    
 
 
 
+
    Proposed resolution:
    
+
+
+
 
 
 
    
-
    1040. Response to UK 238
    
-
    Section: 23.2.4 [associative.reqmts] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-23
    
-
    View other active issues in [associative.reqmts].
    
-
    View all other issues in [associative.reqmts].
    
-
    View all issues with Tentatively Ready status.
    
+
    1035. Response to UK 226
    
+
    Section: 23.2.1 [container.requirements.general] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-08-01
    
+
    View other active issues in [container.requirements.general].
    
+
    View all other issues in [container.requirements.general].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
 
-
    Addresses UK 238
    
+
    Addresses UK 226
    
 
 
    
-Leaving it unspecified whether or not iterator and const_iterator are the
-same type is dangerous, as user code may or may not violate the One
-Definition Rule by providing overloads for 
-both types. It is probably too late to specify a single behaviour, but
-implementors should document what to expect. Observing that problems can be
-avoided by users restricting themselves to using const_iterator, add a note to that effect. 
+<array> must be added to this list. In particular it
+doesn't satisfy: - no swap() function invalidates any
+references, pointers, or iterators referring to the elements of the
+containers being swapped. and probably doesn't satisfy: - no
+swap() function throws an exception.
 
    
 
    
-Suggest Change 'unspecified' to 'implementation defined'.
+If <array> remains a container, this will have to also
+reference array, which will then have to say which of these
+points it satisfies.
 
    
 
 
    [
@@ -29280,36 +23282,55 @@ Summit:
 
 
 
    
-Agree with issue. Agree with adding the note but not with changing the
-normative text. We believe the note provides sufficient guidance.
+Agree. The proposed resolution is incomplete. Further work required.
 
    
 
 
    [
-Batavia (2009-05):
+2009-05-01 Daniel adds:
 ]
    
 
+
 
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
+Issue 1099 also suggests
+adding move constructor to this.
+
    
+
+
    [
+2009-07 post-Frankfurt:
+]
    
+
+
+
    
+Howard is to draft a note that explains what happens to references.
 
    
 
 
+
+
    [
+2009-08-01 Howard provided wording.
+]
    
+
+
 
    Proposed resolution:
    
 
    
-In 23.2.4 [associative.reqmts] p6, add:
+Add a paragraph to 23.3.1.2 [array.special]:
 
    
 
+
    template <Swappable T, size_t N> void swap(array<T,N>& x, array<T,N>& y);
+
    
 
    
--6- iterator of an associative container meets the requirements
-of the BidirectionalIterator concept. For associative
-containers where the value type is the same as the key type, both
-iterator and const_iterator are constant iterators. It
-is unspecified whether or not iterator and
-const_iterator are the same type.
-[Note: iterator and const_iterator have identical semantics in
-this case, and iterator is convertible to const_iterator. Users can avoid
-violating the One Definition Rule by always using const_iterator
-in their function parameter lists -- end note]
+
    
+Effects:
+
    
+
    swap_ranges(x.begin(), x.end(), y.begin());
+
    
+
+
    
+[Note:
+Outstanding iterators, references and pointers may be invalidated.
+— end note]
+
    
+
    
 
    
 
 
@@ -29319,8 +23340,7 @@ in their function parameter lists -- end note]
 
    
 
    1041. Response to UK 239
    
 
    Section: 23.2.4 [associative.reqmts] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-03-15
    
-
    View other active issues in [associative.reqmts].
    
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
    
 
    View all other issues in [associative.reqmts].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
@@ -29364,6 +23384,15 @@ Post Summit Alisdair adds:
 Would value_type be a better return type than key_type?
 
    
 
+
    [
+2009-07 post-Frankfurt:
+]
    
+
+
+
    
+Leave Open. Alisdair to contact Chris Jefferson about this.
+
    
+
 
 
 
    Proposed resolution:
    
@@ -29434,7 +23463,7 @@ exists, returns a.end().
 
    
 
    1042. Response to UK 244
    
 
    Section: 23.3 [sequences] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-03-14
    
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
    
 
    View all other issues in [sequences].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
@@ -29480,6 +23509,15 @@ should extend to complex<T>, and so not be built on the container
 all?
 
    
 
+
    [
+2009-07 post-Frankfurt:
+]
    
+
+
+
    
+Leave Open, pending a post-Concepts Working Draft.
+
    
+
 
 
 
    Proposed resolution:
    
@@ -29597,7 +23635,8 @@ Add at the end of the synopsis in 23.3.6 [vector] p2:
 
    
 
    1043. Response to US 91
    
 
    Section: 29.6 [atomics.types.operations] Status: Review
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-23
    
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
    
+
    View other active issues in [atomics.types.operations].
    
 
    View all other issues in [atomics.types.operations].
    
 
    View all issues with Review status.
    
 
    Discussion:
    
@@ -29649,6 +23688,17 @@ We recommend the proposed resolution be reviewed
 by members of the Concurrency Subgroup.
 
    
 
+
    [
+2009-07 post-Frankfurt:
+]
    
+
+
+
    
+This is likely to be addressed by Lawrence's upcoming paper. He will
+adopt the proposed resolution.
+
    
+
+
 
 
    Proposed resolution:
    
 
    
@@ -29683,117 +23733,6 @@ operations are atomic load operations.
 
 
 
    
-
    1044. Response to UK 325
    
-
    Section: 30.4 [thread.mutex] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-23
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
-
-
    Addresses UK 325
    
-
-
    
-We believe constexpr literal values should be a more natural expression
-of empty tag types than extern objects as it should improve the
-compiler's ability to optimize the empty object away completely.
-
    
-
-
    [
-Summit:
-]
    
-
-
-
    
-Move to review. The current specification is a "hack", and the proposed
-specification is a better "hack".
-
    
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
-
    
-
-
-
    Proposed resolution:
    
-
    
-Change the synopsis in 30.4 [thread.mutex]:
-
    
-
-
    struct defer_lock_t {};
-struct try_to_lock_t {};
-struct adopt_lock_t {};
-
-extern constexpr defer_lock_t defer_lock {};
-extern constexpr try_to_lock_t try_to_lock {};
-extern constexpr adopt_lock_t adopt_lock {};
-
    
-
-
-
-
-
-
-
    
-
    1045. Response to UK 326
    
-
    Section: 30.4.3.2.1 [thread.lock.unique.cons] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-23
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
-
-
    Addresses UK 326
    
-
-
    
-The precondition that the mutex is not owned by this thread offers
-introduces the risk of un-necessary undefined behaviour into the
-program. The only time it matters whether the current thread owns the
-mutex is in the lock operation, and that will happen subsequent to
-construction in this case. The lock operation has the identical
-pre-condition, so there is nothing gained by asserting that precondition
-earlier and denying the program the right to get into a valid state
-before calling lock.
-
    
-
-
    [
-Summit:
-]
    
-
-
-
    
-Agree, move to review.
-
    
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
-
    
-
-
-
    Proposed resolution:
    
-
    
-Strike 30.4.3.2.1 [thread.lock.unique.cons] p7:
-
    
-
-
    unique_lock(mutex_type& m, defer_lock_t);
-
    
-
    
--7- Precondition: If mutex_type is not a recursive mutex
-the calling thread does not own the mutex.
-
    
-
    
-
-
-
-
-
-
-
    
 
    1046. Response to UK 329
    
 
    Section: 30.6 [futures] Status: Open
  Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-03-13
    
@@ -29880,7 +23819,7 @@ think it was a specific design constraint.
 
 
    
 
    1047. Response to UK 334
    
-
    Section: 30.6.4 [futures.unique_future] Status: Review
+
    Section: 30.6.5 [futures.unique_future] Status: Review
  Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-23
    
 
    View other active issues in [futures.unique_future].
    
 
    View all other issues in [futures.unique_future].
    
@@ -29947,7 +23886,7 @@ Keep in Review status.
 
 
    Proposed resolution:
    
 
    
-Add a paragraph to 30.6.4 [futures.unique_future]:
+Add a paragraph to 30.6.5 [futures.unique_future]:
 
    
 
 
    R&& unique_future::get(); 
@@ -29975,7 +23914,7 @@ block on the asynchronous result associated with *this.
 
 
    
 
    1048. Response to UK 335
    
-
    Section: 30.6.4 [futures.unique_future] Status: Open
+
    Section: 30.6.5 [futures.unique_future] Status: Open
  Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-03-13
    
 
    View other active issues in [futures.unique_future].
    
 
    View all other issues in [futures.unique_future].
    
@@ -30082,7 +24021,7 @@ curve std::lib clients will be faced with.
 
 
    
 
    1049. Response to UK 339
    
-
    Section: 30.6.6 [futures.promise] Status: Review
+
    Section: 30.6.4 [futures.promise] Status: Review
  Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-23
    
 
    View other active issues in [futures.promise].
    
 
    View all other issues in [futures.promise].
    
@@ -30120,7 +24059,7 @@ has been issued.
 
 
    Proposed resolution:
    
 
    
-Strike 30.6.6 [futures.promise] p6 and change p7:
+Strike 30.6.4 [futures.promise] p6 and change p7:
 
    
 
 
    promise& operator=(promise&& rhs);
@@ -30145,7 +24084,7 @@ associated state.
 
 
    
 
    1050. Response to UK 340
    
-
    Section: 30.6.6 [futures.promise] Status: Review
+
    Section: 30.6.4 [futures.promise] Status: Review
  Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-23
    
 
    View other active issues in [futures.promise].
    
 
    View all other issues in [futures.promise].
    
@@ -30205,7 +24144,7 @@ was already retrieved. It should throw
 Suggested resolution: 
 
    
 
    
-Replace p12/p13 30.6.6 [futures.promise]: 
+Replace p12/p13 30.6.4 [futures.promise]: 
 
    
 
    
 
    
@@ -30223,7 +24162,7 @@ the associated state has already been retrieved.
 
    
 
    
 
    
-Replace p14 30.6.8 [futures.task]: 
+Replace p14 30.6.7 [futures.task]: 
 
    
 
    
 
    
@@ -30253,7 +24192,7 @@ pending Detlef's forthcoming paper on futures.
 
 
    Proposed resolution:
    
 
    
-Add after p13 30.6.6 [futures.promise]:
+Add after p13 30.6.4 [futures.promise]:
 
    
 
 
    unique_future<R> get_future();
@@ -30275,8 +24214,8 @@ Add after p13 30.6.6 [futures.promise]:
 
 
    
 
    1051. Response to UK 279
    
-
    Section: 24.5.1.2.12 [reverse.iter.opindex], 24.5.3.2.12 [move.iter.op.index] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-03-21
    
+
    Section: 24.5.1.2.12 [reverse.iter.opindex], 24.5.2.2.12 [move.iter.op.index] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-27
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
@@ -30314,6 +24253,30 @@ Howard adds post Summit:
 I am requesting test cases to demonstrate a position.
 
    
 
+
    [
+2009-07-24 Daniel adds:
+]
    
+
+
+
    
+
    
+I recommend NAD. Without concepts we can no longer
+restrict this member in a trivial way. Using decltype the
+declaration would be along the lines of
+
    
+
    static const Iter& __base(); // not defined
+auto operator[](difference_type n) const -> decltype(__base()[-n-1]);
+
    
+
+
    
+but once reverse_iterator is instantiated for some given type
+Iter which cannot form a well-formed expression __base()[-n-1]
+this would cause an ill-formed function declaration, diagnostic
+required, and no silent SFINAE elimination.
+
    
+
+
    
+
 
 
 
    Proposed resolution:
    
@@ -30325,7 +24288,7 @@ I am requesting test cases to demonstrate a position.
 
    
 
    1052. Response to UK 281
    
 
    Section: 24.5.1.2.5 [reverse.iter.opref] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-03-13
    
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-08-01
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
@@ -30353,6 +24316,23 @@ study group formed to come up with a suggested resolution.
 
    
 
    
 
+
    [
+2009-07 post-Frankfurt:
+]
    
+
+
+
    
+Howard to deconceptize. Move to Review after that happens.
+
    
+
+
    [
+2009-08-01 Howard deconceptized:
+]
    
+
+
+
    
+
    
+
 
 
 
    Proposed resolution:
    
@@ -30360,10 +24340,10 @@ study group formed to come up with a suggested resolution.
 Change synopsis in 24.5.1.1 [reverse.iterator]:
 
    
 
-
    template <BidirectionalIterator Iter> 
+
    template <class Iterator> 
 class reverse_iterator { 
   ...
-  typedef Iter::pointer pointer; 
+  typedef typename iterator_traits<Iterator>::pointer pointer;
 
    
 
 
    
@@ -30391,6 +24371,7 @@ Change 24.5.1.2.5 [reverse.iter.opref]:
 
    1053. Response to UK 295
    
 
    Section: 25 [algorithms] Status: Open
  Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-03-13
    
+
    View other active issues in [algorithms].
    
 
    View all other issues in [algorithms].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
@@ -30451,7 +24432,8 @@ clearly addressed by the Summit resolution.
 
    
 
    1054. forward broken
    
 
    Section: 20.3.2 [forward] Status: Open
- Submitter: Howard Hinnant Opened: 2009-03-13  Last modified: 2009-05-23
    
+ Submitter: Howard Hinnant Opened: 2009-03-13  Last modified: 2009-08-02
    
+
    View other active issues in [forward].
    
 
    View all other issues in [forward].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
@@ -30479,6 +24461,125 @@ Batavia (2009-05):
 Move to Open, awaiting the promised paper.
 
    
 
+
    [
+2009-08-02 Howard adds:
+]
    
+
+
+
    
+
    
+My current preferred solution is:
+
    
+
+
    template <class T>
+struct __base_type
+{
+   typedef typename remove_cv<typename remove_reference<T>::type>::type type;
+};
+
+template <class T, class U,
+   class = typename enable_if<
+       !is_lvalue_reference<T>::value ||
+        is_lvalue_reference<T>::value &&
+        is_lvalue_reference<U>::value>::type,
+   class = typename enable_if<
+        is_same<typename __base_type<T>::type,
+                typename __base_type<U>::type>::value>::type>
+inline
+T&&
+forward(U&& t)
+{
+   return static_cast<T&&>(t);
+}
+
    
+
+
    
+This has been tested by Bill, Jason and myself.
+
    
+
+
    
+It allows the following lvalue/rvalue casts:
+
    
+
+
      
+
    1. 
+Cast an lvalue t to an lvalue T (identity).
+
      2. 
+
    2. 
+Cast an lvalue t to an rvalue T.
+
      3. 
+
    3. 
+Cast an rvalue t to an rvalue T (identity).
+
      4. 
+
    
+
+
    
+It disallows:
+
    
+
+
      
+
    1. 
+Cast an rvalue t to an lvalue T.
+
      2. 
+
    2. 
+Cast one type t to another type T (such as int to double).
+
      3. 
+
    
+
+
    
+"a." is disallowed as it can easily lead to dangling references.
+"b." is disallowed as this function is meant to only change the lvalue/rvalue
+characteristic of an expression.
+
    
+
+
    
+Jason has expressed concern that "b." is not dangerous and is useful in contexts
+where you want to "forward" a derived type as a base type.  I find this use case
+neither dangerous, nor compelling.  I.e. I could live with or without the "b."
+constraint.  Without it, forward would look like:
+
    
+
+
    template <class T, class U,
+   class = typename enable_if<
+       !is_lvalue_reference<T>::value ||
+        is_lvalue_reference<T>::value &&
+        is_lvalue_reference<U>::value>::type>
+inline
+T&&
+forward(U&& t)
+{
+   return static_cast<T&&>(t);
+}
+
    
+
+
    
+Or possibly:
+
    
+
+
    template <class T, class U,
+   class = typename enable_if<
+       !is_lvalue_reference<T>::value ||
+        is_lvalue_reference<T>::value &&
+        is_lvalue_reference<U>::value>::type,
+   class = typename enable_if<
+        is_base_of<typename __base_type<U>::type,
+                   typename __base_type<T>::type>::value>::type>
+inline
+T&&
+forward(U&& t)
+{
+   return static_cast<T&&>(t);
+}
+
    
+
+
+
    
+The "promised paper" is not in the post-Frankfurt mailing only because I'm waiting
+for the non-concepts draft.  But I'm hoping that by adding this information here
+I can keep people up to date.
+
    
+
    
+
 
 
 
    Proposed resolution:
    
@@ -30576,7 +24677,6 @@ of the enum T.
 
    1056. Must all Engines and Distributions be Streamable?
    
 
    Section: 26.5 [rand] Status: Open
  Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-31
    
-
    View other active issues in [rand].
    
 
    View all other issues in [rand].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
@@ -30650,32 +24750,25 @@ today.
 
 
 
    
-
    1057. RandomNumberEngineAdaptor
    
-
    Section: 26.5 [rand] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-23
    
-
    View other active issues in [rand].
    
-
    View all other issues in [rand].
    
-
    View all issues with Open status.
    
+
    1062. Missing insert_iterator for stacks/queues
    
+
    Section: 24.7 [insert.iterators] Status: Tentatively NAD Future
+ Submitter: Alisdair Meredith Opened: 2009-03-13  Last modified: 2009-07-29
    
+
    View other active issues in [insert.iterators].
    
+
    View all other issues in [insert.iterators].
    
+
    View all issues with Tentatively NAD Future status.
    
 
    Discussion:
    
 
 
    
-The RandomNumberEngineAdaptor concept breaks precedent in the
-way the library has been specified by grouping requirements into a
-concept that is never actually used in the library.
-
    
-
    
-This is undoubtedly a very helpful device for documentation, but we are not
-comfortable with the precedent - especially as we have rejected national
-body comments on the same grounds.
-
    
-
    
-Suggest either removing the concept, or providing an algorithm/type that
-requires this concept in their definition (such as a factory function to
-create new engines).
+It is odd that we have an iterator to insert into a vector, but not an
+iterator to insert into a vector that is adapted as a stack. The standard
+container adapters all have a common interface to push and pop so it should
+be simple to create an iterator adapter to complete the library support.
 
    
+
 
    
-The preference is to create a single new algorithm and retain the value of
-the existing documentation.
+We should provide an AdaptedContainer concept supporting push and pop
+operations. Create a new insert iterator and factory function that inserts
+values into the container by calling push.
 
    
 
 
    [
@@ -30684,217 +24777,72 @@ Batavia (2009-05):
 
 
    
 
    
-Walter points out that it is unlikely that any algorithm would ever
-require this concept, but that the concept nonetheless is useful as
-documentation, and (via concept maps) as a means of checking specific adapters.
-
    
-
    
-Alisdair disagrees as to the concept's value as documentation.
-
    
-
    
-Marc points out that the RandomNumberDistribution
-is also a concept not used elsewhere in the Standard.
-
    
-
    
-Pete agrees that a policy of not inventing concepts
-that aren't used in the Standard is a good starting point,
-but should not be used as a criterion for rejecting a concept.
+Walter recommends NAD Future.
 
    
 
    
-Move to Open.
+Move to Open, and recommend deferring the issue until after the next
+Committee Draft is issued.
 
    
 
    
 
-
-
    Proposed resolution:
    
-
-
-
-
-
-
    
-
    1058. New container issue
    
-
    Section: 23.2.3 [sequence.reqmts] Status: Tentatively NAD Editorial
- Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-05-23
    
-
    View other active issues in [sequence.reqmts].
    
-
    View all other issues in [sequence.reqmts].
    
-
    View all issues with Tentatively NAD Editorial status.
    
-
    Discussion:
    
-
-
    
-Sequence containers 23.2.3 [sequence.reqmts]:
-
    
-
-
    
-The return value of new calls added to table 83 are not specified.
-
    
-
 
    [
-Batavia (2009-05):
+2009-07-29 Howard moves to Tentatively NAD Future.
 ]
    
 
+
 
    
-
    
-We agree with the proposed resolution.
-
    
-
    
-Move to NAD Editorial.
-
    
+A poll on the LWG reflector voted unanimously to move this issue to Tentatively NAD Future.
 
    
 
 
 
    Proposed resolution:
    
-
    
-Add after p6 23.2.3 [sequence.reqmts]:
-
    
-
-
    
-
    
--6- ...
-
    
-
    
-The iterator returned from a.insert(p,rv) points to the copy of rv
-inserted into a.
-
    
-
    
-The iterator returned from a.emplace(p, args) points to the new
-element constructed from args inserted into a.
-
    
-
    
 
 
 
 
 
 
    
-
    1059. Usage of no longer existing FunctionType concept
    
-
    Section: 20.7.16.2 [func.wrap.func] Status: Open
- Submitter: Daniel Krügler Opened: 2009-03-13  Last modified: 2009-05-23
    
-
    View other active issues in [func.wrap.func].
    
-
    View all other issues in [func.wrap.func].
    
+
    1064. Response to UK 152
    
+
    Section: 17.3.15 [defns.obj.state] Status: Open
+ Submitter: Howard Hinnant Opened: 2009-03-15  Last modified: 2009-03-15
    
 
    View all issues with Open status.
    
 
    Discussion:
    
+
+
    Addresses UK 152
    
+
 
    
-Due to a deliberate core language decision, the earlier called
-"foundation" concept std::FunctionType had been removed in
-N2773
-shortly
-before the first "conceptualized" version of the WP
-(N2798)
-had been
-prepared. This caused a break of the library, which already used this
-concept in the adapted definition of std::function
-(20.7 [function.objects]/2, header <functional> synopsis and
-20.7.16.2 [func.wrap.func]).
-
    
-
    
-A simple fix would be to either (a) make std::function's primary template
-unconstrained or to (b) add constraints based on existing (support) concepts.
-A more advanced fix would (c) introduce a new library concept.
-
    
-
    
-The big disadvantage of (a) is, that users can define templates which
-cause compiler errors during instantiation time because of under-constrainedness
-and would thus violate the basic advantage of constrained
-code.
-
    
-
    
-For (b), the ideal constraints for std::function's template parameter would
-be one which excludes everything else but the single provided partial
-specialization that matches every "free function" type (i.e. any function
-type w/o cv-qualifier-seq and w/o ref-qualifier).
-Expressing such a type as as single requirement would be written as
-
    
-
    template<typename T>
-requires ReferentType<T> // Eliminate cv void and function types with cv-qual-seq
-                         //   or ref-qual (depending on core issue #749)
-      && PointeeType<T>  // Eliminate reference types
-      && !ObjectType<T>  // Eliminate object types
-
    
-
    
-Just for completeness approach (c), which would make sense, if the
-library has more reasons to constrain for free function types:
-
    
-
    auto concept FreeFunctionType<typename T>
-  : ReferentType<T>, PointeeType<T>, MemberPointeeType<T>
-{
-  requires !ObjectType<T>;
-}
-
    
-
    
-I mention that approach because I expect that free function types belong
-to the most natural type categories for every days coders. Potential
-candidates in the library are addressof and class template packaged_task.
+Object state is using a definition of object (instance of a class) from
+outside the standard, rather than the 'region of storage' definiton in
+1.8 [intro.object]p1
 
    
 
 
    [
-Batavia (2009-05):
+Summit:
 ]
    
 
 
    
-
    
-Alisdair would prefer to have a core-supported FunctionType concept
-in order that any future changes be automatically correct
-without need for a library solution to catch up;
-he points to type traits as a precedent.
-Further, he believes that a published concept can't in the future
-be changed.
-
    
-
    
-Bill feels this category of entity would change sufficiently slowly
-that he would be willing to take the risk.
-
    
-
    
-Of the discussed solutions, we tend toward option (c).
-We like the idea of having a complete taxonomy of native types,
-and perhaps erred in trimming the set.
-
    
-
    
-We would like to have this issue reviewed by Core and would like
-their feedback.  Move to Open.
-
    
+We think we're removing this; See X [func.referenceclosure.cons].
 
    
 
 
 
    Proposed resolution:
    
-
      
-
    1. 
 
      
-Change in 20.7 [function.objects]/2, Header <functional> synopsis:
 
      
-
      // 20.6.16 polymorphic function wrappers:
-class bad_function_call;
-template<FunctionTypeReferentType F>
-requires PointeeType<F> && !ObjectType<F>
-class function; // undefined
-
      
-
      2. 
-
    2. 
-
      
-Change in 20.7.16.2 [func.wrap.func]:
-
      
-
      namespace std {
-template<FunctionTypeReferentType F>
-requires PointeeType<F> && !ObjectType<F>
-class function; // undefined
-
      
-
      3. 
-
    
 
 
 
 
 
 
    
-
    1060. Embedded nulls in NTBS
    
-
    Section: 17.5.2.1.4.1 [byte.strings] Status: Tentatively NAD Editorial
- Submitter: Alisdair Meredith Opened: 2009-03-13  Last modified: 2009-05-23
    
-
    View all issues with Tentatively NAD Editorial status.
    
+
    1068. class random_device should be movable
    
+
    Section: 26.5.6 [rand.device] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-03-18  Last modified: 2009-05-23
    
+
    View all other issues in [rand.device].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
 
 
    
-Definition of null-terminated sequences allow for embedded nulls. This is
-surprising, and probably not supportable with the intended use cases.
+class random_device should be movable.
 
    
 
 
    [
@@ -30902,12 +24850,11 @@ Batavia (2009-05):
 ]
    
 
 
    
-We agree with the issue, but believe this can be handled editorially.
-Move to NAD Editorial.
+Move to Open, and recommend this issue be deferred until after the next
+Committee Draft is issued.
 
    
 
 
-
 
    Proposed resolution:
    
 
 
@@ -30915,15 +24862,15 @@ Move to NAD Editorial.
 
 
 
    
-
    1061. Bad indexing for tuple access to pair (Editorial?)
    
-
    Section: 20.3.4 [pair.astuple] Status: Tentatively NAD Editorial
- Submitter: Alisdair Meredith Opened: 2009-03-13  Last modified: 2009-05-23
    
-
    View all issues with Tentatively NAD Editorial status.
    
+
    1069. class seed_seq should support efficient move operations
    
+
    Section: 26.5.7.1 [rand.util.seedseq] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-03-18  Last modified: 2009-05-23
    
+
    View all other issues in [rand.util.seedseq].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
 
 
    
-The definition of get implies that get must return the second element if
-given a negative integer.
+class seed_seq should support efficient move operations.
 
    
 
 
    [
@@ -30931,910 +24878,803 @@ Batavia (2009-05):
 ]
    
 
 
    
-Move to NAD Editorial.
+Move to Open, and recommend this issue be deferred until after the next
+Committee Draft is issued.
 
    
 
 
-
 
    Proposed resolution:
    
-
    
-20.3.4 [pair.astuple] p5:
-
    
-
-
    template<int size_t I, class T1, class T2> 
-  requires True<(I < 2)> 
-  const P& get(const pair<T1, T2>&);
-
    
-
    
-
 
 
 
 
 
 
    
-
    1062. Missing insert_iterator for stacks/queues
    
-
    Section: 24.7 [insert.iterators] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-13  Last modified: 2009-05-23
    
-
    View other active issues in [insert.iterators].
    
-
    View all other issues in [insert.iterators].
    
+
    1071. is_bind_expression should derive from integral_constant<bool>
    
+
    Section: 20.7.12.1.1 [func.bind.isbind] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-03-19  Last modified: 2009-05-31
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
 
    
-It is odd that we have an iterator to insert into a vector, but not an
-iterator to insert into a vector that is adapted as a stack. The standard
-container adapters all have a common interface to push and pop so it should
-be simple to create an iterator adapter to complete the library support.
+Class template is_bind_expression 20.7.12.1.1 [func.bind.isbind]:
 
    
 
+
    namespace std {
+  template<class T> struct is_bind_expression {
+    static const bool value = see below;
+  };
+}
+
    
 
    
-We should provide an AdaptedContainer concept supporting push and pop
-operations. Create a new insert iterator and factory function that inserts
-values into the container by calling push.
+is_bind_expression should derive from std::integral_constant<bool> like
+other similar trait types.
 
    
 
 
    [
+Daniel adds:
+]
    
+
+
    
+We need the same thing for the trait is_placeholder as well.
+
    
+
    [
+2009-03-22 Daniel provided wording.
+]
    
+
+
+
    [
 Batavia (2009-05):
 ]
    
 
 
    
 
    
-Walter recommends NAD Future.
+We recommend this be deferred until after the next Committee Draft is issued.
 
    
 
    
-Move to Open, and recommend deferring the issue until after the next
-Committee Draft is issued.
+Move to Open.
 
    
 
    
 
-
-
    Proposed resolution:
    
-
+
    [
+2009-05-31 Peter adds:
+]
    
 
 
+
    
+
    
+I am opposed to the proposed resolution and to the premise of the issue
+in general. The traits's default definitions should NOT derive from
+integral_constant, because this is harmful, as it misleads people into
+thinking that is_bind_expression<E> always derives from
+integral_constant, whereas it may not.
+
    
+
    
+is_bind_expression and is_placeholder allow user
+specializations, and in fact, this is their primary purpose. Such user
+specializations may not derive from integral_constant, and the
+places where is_bind_expression and is_placeholder are
+used intentionally do not require such derivation.
+
    
+
    
+The long-term approach here is to switch to
+BindExpression<E> and Placeholder<P>
+explicit concepts, of course, but until that happens, I say leave them
+alone.
+
    
+
    
 
 
-
    
-
    1063. 03 iterator compatibilty
    
-
    Section: D.10.4 [iterator.backward] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-15  Last modified: 2009-05-23
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
 
+
    Proposed resolution:
    
+
      
+
    1. 
 
      
-Which header must a user #include to obtain the library-supplied
-concept_maps declared in this paragraph?
+In 20.7.12.1.1 [func.bind.isbind] change as indicated:
 
      
-
+
      namespace std {
+ template<class T> struct is_bind_expression : integral_constant<bool, see below> { };{
+   static const bool value = see below;
+ };
+}
+
      
+
      2. 
+
    2. 
 
      
-This is important information, as existing user code will break if this
-header is not included, and we should make a point of mandating this header
-is #include-d by library headers likely to make use of it, notably
-<algorithm>.  See issue 1001 for more details.
+In 20.7.12.1.1 [func.bind.isbind]/2 change as indicated:
 
      
-
-
      [
-Batavia (2009-05):
-]
      
-
+
      static const bool value;
+
      
 
      
-We agree with the direction of the proposed resolution.
-Move to Tentatively Ready.
+-2- true if T is a type returned from bind, false otherwise.
+  If T is a type returned from bind, is_bind_expression<T> shall
+be publicly derived from
+        integral_constant<bool, true>, otherwise it shall be
+publicly derived from
+          integral_constant<bool, false>.
 
      
-
-
-
      Proposed resolution:
      
-
      Change D.10 [depr.lib.iterator.primitives], Iterator primitives, as
-indicated:
      
-
+
      
+
      3. 
+
    3. 
+
      
+In 20.7.12.1.2 [func.bind.isplace] change as indicated:
+
      
+
      namespace std {
+ template<class T> struct is_placeholder : integral_constant<int, see below> { };{
+   static const int value = see below;
+ };
+}
+
      
+
      4. 
+
    4. 
+
      
+In 20.7.12.1.2 [func.bind.isplace]/2 change as indicated:
+
      
+
      static const int value;
+
      
 
      
-  
      To simplify the use of iterators and provide backward compatibility with
-  previous C++ Standard Libraries,
-  the library provides several classes and functions. Unless otherwise
-  specified, these classes and functions shall be defined in header <iterator>.
      
+-2- value is J if T is the type of std::placeholders::_J, 0 otherwise.
+  If T is the type of std::placeholders::_J, is_placeholder<T>
+shall be publicly
+          derived from integral_constant<int, J> otherwise it shall
+be publicly derived
+          from integral_constant<int, 0>.
 
      
-
      Change D.10.4 [iterator.backward], Iterator backward compatibility, as
-indicated:
      
-
      
-  
      The library provides concept maps that allow iterators specified with
-  iterator_traits to interoperate with
-  algorithms that require iterator concepts. These concept maps shall be
-  defined in the same header that defines the iterator. [Example:
      
 
      
+
      5. 
+
    
 
 
 
 
 
 
    
-
    1064. Response to UK 152
    
-
    Section: 17.3.15 [defns.obj.state] Status: Open
- Submitter: Howard Hinnant Opened: 2009-03-15  Last modified: 2009-03-15
    
+
    1075. Response to US 65, US 74.1
    
+
    Section: 20 [utilities], 23 [containers] Status: Open
+ Submitter: Alan Talbot Opened: 2009-03-20  Last modified: 2009-06-10
    
+
    View all other issues in [utilities].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
+
    Addresses US 65 and US 74.1
    
 
-
    Addresses UK 152
    
-
-
    
-Object state is using a definition of object (instance of a class) from
-outside the standard, rather than the 'region of storage' definiton in
-1.8 [intro.object]p1
-
    
-
-
    [
-Summit:
-]
    
+
    US 65:
    
 
 
    
-We think we're removing this; See 20.7.18.1 [func.referenceclosure.cons].
-
    
+Scoped allocators and allocator propagation traits add a small amount of
+utility at the cost of a great deal of machinery. The machinery is user
+visible, and it extends to library components that don't have any
+obvious connection to allocators, including basic concepts and simple
+components like pair and tuple.
 
+
    Suggested resolution:
    
 
-
    Proposed resolution:
    
 
    
+Sketch of proposed resolution: Eliminate scoped allocators, replace
+allocator propagation traits with a simple uniform rule (e.g. always
+propagate on copy and move), remove all mention of allocators from
+components that don't explicitly allocate memory (e.g. pair), and adjust
+container interfaces to reflect this simplification.
 
    
+
    
+Components that I propose eliminating include HasAllocatorType,
+is_scoped_allocator, allocator_propagation_map, scoped_allocator_adaptor,
+and ConstructibleAsElement.
+
    
+
    
 
+
    US 74.1:
    
 
-
-
-
-
    
-
    1065. Response to UK 168
    
-
    Section: 17.6.1.1 [contents] Status: Tentatively Ready
- Submitter: Howard Hinnant Opened: 2009-03-15  Last modified: 2009-05-23
    
-
    View other active issues in [contents].
    
-
    View all other issues in [contents].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
-
    Addresses UK 168
    
+
    
+
    
+Scoped allocators represent a poor trade-off for standardization, since
+(1) scoped-allocator--aware containers can be implemented outside the
+C++ standard library but used with its algorithms, (2) scoped
+allocators only benefit a tiny proportion of the C++ community
+(since few C++ programmers even use today's allocators), and (3) all C++
+users, especially the vast majority of the C++ community that won't ever
+use scoped allocators are forced to cope with the interface complexity
+introduced by scoped allocators.
+
    
 
    
-We should make it clear (either by note or normatively) that namespace
-std may contain inline namespaces, and that entities specified to be
-defined in std may in fact be defined in one of these inline namespaces.
-(If we're going to use them for versioning, eg when TR2 comes along,
-we're going to need that.)
+In essence, the larger community will suffer to support a very small
+subset of the community who can already implement their own
+data structures outside of the standard library. Therefore, scoped
+allocators should be removed from the working paper.
 
    
-
 
    
-Replace "namespace std or namespaces nested within namespace std" with
-"namespace std or namespaces nested within namespace std or inline
-namespaces nested directly or indirectly within namespace std"
+Some evidence of the complexity introduced by scoped allocators:
 
    
-
-
    [
-Summit:
-]
    
-
-
    
-adopt UK words (some have reservations whether it is correct)
-
    
-
-
    [
-2009-05-09 Alisdair improves the wording.
-]
    
-
-
-
    [
-Batavia (2009-05):
-]
    
-
 
    
 
    
-Bill believes there is strictly speaking no need to say that
-because no portable test can detect the difference.
-However he agrees that it doesn't hurt to say this.
+20.3.3 [pairs], 20.5 [tuple]: Large increase in the
+number of pair and tuple constructors.
 
    
 
    
-Move to Tentatively Ready.
+23 [containers]: Confusing "AllocatableElement" requirements throughout.
 
    
 
    
+
    Suggested resolution:
    
 
-
-
    Proposed resolution:
    
 
    
-Change 17.6.1.1 [contents] p2:
+Remove support for scoped allocators from the working paper. This
+includes at least the following changes:
 
    
 
 
    
-All library entities except macros, operator new and
-operator delete are defined within the namespace std or
-namespaces nested within namespace std.
-It is unspecified whether names declared in a specific namespace
-are declared directly in that namespace, or in an inline namespace inside
-that namespace. [Footnote: This gives implementers freedom to support
-multiple configurations of the library.]
-
    
-
-
-
-
-
-
    
-
    1066. Response to UK 189 and JP 27
    
-
    Section: 18 [language.support] Status: Tentatively Ready
- Submitter: Howard Hinnant Opened: 2009-03-15  Last modified: 2009-05-23
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
-
    Addresses UK 189 and JP 27
    
 
    
-The addition of the [[noreturn]] attribute to the language will be an
-important aid for static analysis tools.
+Remove 20.8.3 [allocator.element.concepts]
+
    
+
    
+Remove 20.8.5 [allocator.adaptor]
+
    
+
    
+Remove  [construct.element]
 
    
-
 
    
-The following functions should be declared in C++ with the
-[[noreturn]] attribute: abort exit
-quick_exit terminate unexpected
-rethrow_exception throw_with_nested.
+In Clause 23 [containers]: replace requirements naming the
+AllocatableElement concept with requirements naming CopyConstructible,
+MoveConstructible, DefaultConstructible, or Constructible, as
+appropriate.
 
    
+
    
+
+
    
 
 
    [
-Summit:
+Post Summit Alan moved from NAD to Open.
 ]
    
 
-
    
-Agreed.
-
    
 
 
    [
-Batavia (2009-05):
+2009-05-15 Ganesh adds:
 ]
    
 
-
    
-We agree with the proposed resolution.
-Move to Tentatively Ready.
-
    
-
 
-
    Proposed resolution:
    
+
    
 
    
-Change 18.5 [support.start.term] p3:
+The requirement AllocatableElement should not be replaced with
+Constructible on the emplace_xxx() functions as suggested. In the
+one-parameter case the Constructible requirement is not satisfied when
+the constructor is explicit (as per 14.10.2.1 [concept.map.fct], twelfth
+bullet) but we do want to allow explicit constructors in emplace, as the
+following example shows:
 
    
 
-
    
-
    -2- ...
    
-
    void abort [[noreturn]] (void)
-
    
-
    -3- ...
    
-
    -6- ...
    
-
    void exit [[noreturn]] (int status)
-
    
-
    -7- ...
    
-
    -11- ...
    
-
    void quick_exit [[noreturn]] (int status)
-
    
-
    -12- ...
    
-
    
+
    vector<shared_ptr<int>> v;
+v.emplace_back(new int); // should be allowed
+
    
 
 
    
-Change the <exception> synopsis in 18.8 [support.exception]:
+If the issue is accepted and scoped allocators are removed, I suggest to
+add a new pair of concepts to 20.2.7 [concept.construct], namely:
 
    
 
-
    void unexpected [[noreturn]] ();
-...
-void terminate [[noreturn]] ();
-...
-void rethrow_exception [[noreturn]] (exception_ptr p);
-...
-template <class T> void throw_with_nested [[noreturn]] (T&& t); // [[noreturn]]
+
    auto concept HasExplicitConstructor<typename T, typename... Args> {
+ explicit T::T(Args...);
+}
+
+auto concept ExplicitConstructible<typename T, typename... Args>
+ : HasExplicitConstructor<T, Args...>, NothrowDestructible<T>
+{ }
 
    
 
 
    
-Change 18.8.2.4 [unexpected]:
+We should then use ExplicitConstructible as the requirement for all
+emplace_xxx() member functions.
+
    
+
    
+For coherence and consistency with the similar concepts
+Convertible/ExplicitlyConvertible, we might also consider changing
+Constructible to:
 
    
 
-
    void unexpected [[noreturn]] ();
+
    auto concept Constructible<typename T, typename... Args>
+ : HasConstructor<T, Args...>, ExplicitConstructible<T, Args...>
+{ }
 
    
 
 
    
-Change 18.8.3.3 [terminate]:
+Moreover, all emplace-related concepts in 23.2.6 [container.concepts]
+should also use ExplicitConstructible instead of Constructible in the
+definitions of their axioms. In fact the concepts in 23.2.6 [container.concepts] should be
+corrected even if the issue is not accepted.
+
    
+
    
+On the other hand, if the issue is not accepted, the scoped allocator
+adaptors should be fixed because the following code:
 
    
 
-
    void terminate [[noreturn]] ();
+
    template <typename T> using scoped_allocator = scoped_allocator_adaptor<allocator<T>>;
+
+vector<shared_ptr<int>, scoped_allocator<shared_ptr<int>>> v;
+v.emplace_back(new int); // ops! doesn't compile
 
    
 
 
    
-Change 18.8.5 [propagation]:
+doesn't compile, as the member function construct() of the scoped
+allocator requires non-explicit constructors through concept
+ConstructibleWithAllocator. Fixing that is not difficult but probably
+more work than it's worth and is therefore, IMHO, one more reason in
+support of the complete removal of scoped allocators.
 
    
+
    
 
-
    void rethrow_exception [[noreturn]] (exception_ptr p);
-
    
+
    [
+2009-06-09 Alan adds:
+]
    
+
+
+
    
+
    
+I reopened this issue because I did not think that these National Body
+comments were adequately addressed by marking them NAD. My understanding
+is that something can be marked NAD if it is clearly a misunderstanding
+or trivial, but a substantive issue that has any technical merit
+requires a disposition that addresses the concerns.
+
    
+
    
+The notes in the NB comment list (US 65 & US 74.1) say that:
+
    
+
      
+
    1. 
+this issue has not introduced any new arguments not previously discussed,
+
      2. 
+
    2. 
+the vote (4-9-3) was not a consensus for removing scoped allocators,
+
      3. 
+
    3. 
+the issue is resolved by
+N2840.
+
      4. 
+
    
+
    
+My opinion is:
+
    
+
      
+
    1. 
+there are new arguments in both comments regarding concepts (which were
+not present in the library when the scoped allocator proposal was voted
+in),
+
      2. 
+
    2. 
+the vote was clearly not a consensus for removal, but just saying there
+was a vote does not provide a rationale,
+
      3. 
+
    3. 
+I do not believe that N2840 addresses these comments (although it does
+many other things and was voted in with strong approval).
+
      4. 
+
    
 
 
    
-In the synopsis of 18.8.6 [except.nested] and the definition area change:
+My motivation to open the issue was to ensure that the NB comments were
+adequately addressed in a way that would not risk a "no" vote on our
+FCD. If there are responses to the technical concerns raised, then
+perhaps they should be recorded. If the members of the NB who authored
+the comments are satisfied with N2840 and the other disposition remarks
+in the comment list, then I am sure they will say so. In either case,
+this issue can be closed very quickly in Frankfurt, and hopefully will
+have helped make us more confident of approval with little effort. If in
+fact there is controversy, my thought is that it is better to know now
+rather than later so there is more time to deal with it.
 
    
+
    
 
-
    template <class T> void throw_with_nested [[noreturn]] (T&& t); // [[noreturn]]
-
    
+
+
+
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1067. simplified wording for inner_product
    
-
    Section: 26.7 [numeric.ops] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-17  Last modified: 2009-05-23
    
-
    View all issues with Tentatively Ready status.
    
+
    1076. unary/binary_negate need constraining and move support
    
+
    Section: 20.7.11 [negators] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-03-20  Last modified: 2009-05-23
    
+
    View all issues with Open status.
    
 
    Discussion:
    
-
-
    
-One of the motivating examples for introducing requirements-aliases was to
-simplify the wording of the inner_product requirements.  As the paper
-adopting the feature and constrained wording for the library went through in
-the same meeting, it was not possible to make the change at the time.  The
-simpler form should be adopted now though.  Similarly, most the other
-numerical algorithms can benefit from a minor cleanup.
-
    
 
    
-Note that in each case, the second more generalised form of the algorithm
-does not benefit, as there are already named constraints supplied by the
-template type parameters.
+The class templates unary/binary_negate need constraining and move support.
 
    
-
-
    [
-2009-05-02 Daniel adds:
-]
    
-
-
-
    
 
    
-one part of the suggested resolution suggests the removal of the
-MoveConstructible<T> requirement from
-inner_product. According to 26.7.2 [inner.product]
+Ideally these classes would be deprecated, allowing unary/binary_function to
+also be deprecated.  However, until a generic negate adaptor is introduced
+that can negate any Callable type, they must be supported so should be
+constrained.  Likewise, they should be movable, and support adopting a
+move-only predicate type.
 
    
-
-
    
-Computes its result by initializing the accumulator acc with the
-initial value init
-
    
-
 
    
-this step requires at least MoveConstructible.
+In order to preserve ABI compatibility, new rvalue overloads are supplied in
+preference to changing the existing pass-by-const-ref to pass-by-value.
 
    
-
 
    
-Therefore I strongly suggest to take this removal back (Note also
-that the corresponding overload with a functor argument still has
-the same MoveConstructible<T> requirement).
+Do not consider the issue of forwarding mutable lvalues at this point,
+although remain open to another issue on the topic.
 
    
-
    
 
 
    [
-Batavia (2009-05):
+2009-05-01 Daniel adds:
 ]
    
 
 
    
 
    
-We agree with the proposed resolution as amended by Daniel's suggestion
-to restore MoveConstructible,
-reflected in the updated proposed resolution below.
-
    
-
    
-Move to Tentatively Ready.
+IMO the currently proposed resolution needs some updates
+because it is ill-formed at several places:
 
    
-
    
-
 
-
    Proposed resolution:
    
+
      
+
    1. 
 
      
-Change in 26.7 [numeric.ops] and  [accumulate]:
+In concept AdaptableUnaryFunction change
 
      
-
-
      template <InputIterator Iter, MoveConstructible T>
- requires add = HasPlus<T, Iter::reference>
-       && HasAssign<T, HasPlus<T, Iter::reference> add::result_type>
- T accumulate(Iter first, Iter last, T init);
+
      typename X::result_type;
+typename X::argument_type;
 
      
-
 
      
-Change in 26.7 [numeric.ops] and 26.7.2 [inner.product]:
+to
 
      
-
-
      template <InputIterator Iter1, InputIterator Iter2, MoveConstructible T>
-  requires mult = HasMultiply<Iter1::reference, Iter2::reference>
-        && add = HasPlus<T, HasMultiply<Iter1::reference, Iter2::reference> mult::result_type>
-        && HasAssign< 
-             T,
-             HasPlus<T,
-                     HasMultiply<Iter1::reference, Iter2::reference>::result_type> add::result_type>
-  T inner_product(Iter1 first1, Iter1 last1, Iter2 first2, T init);
+
      Returnable result_type = typename X::result_type;
+typename argument_type = typename X::argument_type;
 
      
-
 
      
-Change in 26.7 [numeric.ops] and 26.7.3 [partial.sum]:
+[The replacement "Returnable result_type" instead of "typename
+result_type" is non-editorial, but maybe you prefer that as well]
 
      
-
-
      template <InputIterator InIter, OutputIterator<auto, const InIter::value_type&> OutIter>
-  requires add = HasPlus<InIter::value_type, InIter::reference>
-        && HasAssign<InIter::value_type,
-                     HasPlus<InIter::value_type, InIter::reference> add::result_type>
-        && Constructible<InIter::value_type, InIter::reference>
-  OutIter partial_sum(InIter first, InIter last, OutIter result);
-
      
-
+
      2. 
+
    2. 
 
      
-Change in 26.7 [numeric.ops] and 26.7.4 [adjacent.difference]:
+In concept AdaptableBinaryFunction change
 
      
-
-
      template <InputIterator InIter, OutputIterator<auto, const InIter::value_type&> OutIter>
-  requires sub = HasMinus<InIter::value_type, InIter::value_type>
-        && Constructible<InIter::value_type, InIter::reference>
-        && OutputIterator<OutIter, HasMinus<InIter::value_type, InIter::value_type> sub::result_type>
-        && MoveAssignable<InIter::value_type>
-  OutIter adjacent_difference(InIter first, InIter last, OutIter result);
+
      typename X::result_type;
+typename X::first_argument_type;
+typename X::second_argument_type;
 
      
-
-
-
-
-
-
-
      
-
      1068. class random_device should be movable
      
-
      Section: 26.5.6 [rand.device] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-18  Last modified: 2009-05-23
      
-
      View all other issues in [rand.device].
      
-
      View all issues with Open status.
      
-
      Discussion:
      
-
 
      
-class random_device should be movable.
+to
 
      
-
-
      [
-Batavia (2009-05):
-]
      
-
-
      
-Move to Open, and recommend this issue be deferred until after the next
-Committee Draft is issued.
-
      
-
-
-
      Proposed resolution:
      
-
-
-
-
-
-
      
-
      1069. class seed_seq should support efficient move operations
      
-
      Section: 26.5.7.1 [rand.util.seedseq] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-18  Last modified: 2009-05-23
      
-
      View all other issues in [rand.util.seedseq].
      
-
      View all issues with Open status.
      
-
      Discussion:
      
-
+
      Returnable result_type = typename X::result_type;
+typename first_argument_type = typename X::first_argument_type;
+typename second_argument_type = typename X::second_argument_type;
+
      
 
      
-class seed_seq should support efficient move operations.
+[The replacement "Returnable result_type" instead of "typename
+result_type" is non-editorial, but maybe you prefer that as well.]
 
      
+
      3. 
 
-
      [
-Batavia (2009-05):
-]
      
-
-
      
-Move to Open, and recommend this issue be deferred until after the next
-Committee Draft is issued.
-
      
-
-
-
      Proposed resolution:
      
-
-
-
-
-
-
      
-
      1070. Ambiguous move overloads in function
      
-
      Section: 20.7.16.2 [func.wrap.func] Status: Tentatively Ready
- Submitter: Howard Hinnant Opened: 2009-03-19  Last modified: 2009-05-23
      
-
      View other active issues in [func.wrap.func].
      
-
      View all other issues in [func.wrap.func].
      
-
      View all issues with Tentatively Ready status.
      
-
      Discussion:
      
+
    3. 
 
      
-The synopsis in 20.7.16.2 [func.wrap.func] says:
+In class unary/binary_function
 
      
-
-
      template<Returnable R, CopyConstructible... ArgTypes> 
-class function<R(ArgTypes...)>
-{
-    ...
-    template<class F> 
-      requires CopyConstructible<F> && Callable<F, ArgTypes...> 
-            && Convertible<Callable<F, ArgTypes...>::result_type, R> 
-      function(F); 
-    template<class F> 
-      requires CopyConstructible<F> && Callable<F, ArgTypes...> 
-            && Convertible<Callable<F, ArgTypes...>::result_type, R> 
-      function(F&&);
-    ...
-    template<class F, Allocator Alloc> function(allocator_arg_t, const Alloc&, F); 
-    template<class F, Allocator Alloc> function(allocator_arg_t, const Alloc&, F&&);
-    ...
-    template<class F> 
-      requires CopyConstructible<F> && Callable<F, ArgTypes..> 
-            && Convertible<Callable<F, ArgTypes...>::result_type 
-      function& operator=(F); 
-    template<class F> 
-      requires CopyConstructible<F> && Callable<F, ArgTypes...> 
-            && Convertible<Callable<F, ArgTypes...>::result_type, R> 
-      function& operator=(F&&);
-    ...
-};
-
      
-
+
        
+
      1. 
+I suggest to change "ReturnType" to "Returnable" in both cases.
+
        2. 
+
      2. 
+I think you want to replace the remaining occurrences of "Predicate" by "P"
+(in both classes in copy/move from a predicate)
+
        3. 
+
      
+
      4. 
+
    4. 
 
      
-Each of the 3 pairs above are ambiguous.  We need only one of each pair, and we
-could do it with either one.  If we choose the F&& version we
-need to bring decay into the definition to get the pass-by-value behavior.
-In the proposed wording I've gotten lazy and just used the pass-by-value signature.
+I think you need to change the proposed signatures of not1 and not2, because
+they would still remain unconstrained: To make them constrained at least a
+single requirement needs to be added to enable requirement implication. This
+could be done via a dummy ("requires True<true>") or just explicit as follows:
 
      
-
-
      [
-2009-05-01 Daniel adds:
-]
      
-
-
+
        
+
      1. 
+
        template <AdaptableUnaryFunction P>
+requires Predicate< P, P::argument_type>
+unary_negate<P> not1(const P&& pred);
+template <AdaptableUnaryFunction P>
+requires Predicate< P, P::argument_type >
+unary_negate<P> not1(P&& pred);
+
        
 
        
-1024 modifies the second removed constructor.
+-3- Returns: unary_negate<P>(pred).
 
        
-
-
        [
-Batavia (2009-05):
-]
        
-
-
        
-
        
-We briefly discussed whether we ought support moveable function objects,
-but decided that should be a separate issue if someone cares to propose it.
-
        
-
        
-Move to Tentatively Ready.
-
        
 
        
-
-
-
        Proposed resolution:
        
 
        
-Change the synopsis of 20.7.16.2 [func.wrap.func], and remove the associated definitions in
-20.7.16.2.1 [func.wrap.func.con]:
+[Don't we want a move call for the second overload as in
 
        
-
-
        template<Returnable R, CopyConstructible... ArgTypes> 
-class function<R(ArgTypes...)>
-{
-    ...
-    template<class F> 
-      requires CopyConstructible<F> && Callable<F, ArgTypes...> 
-            && Convertible<Callable<F, ArgTypes...>::result_type, R> 
-      function(F); 
-    template<class F> 
-      requires CopyConstructible<F> && Callable<F, ArgTypes...> 
-            && Convertible<Callable<F, ArgTypes...>::result_type, R> 
-      function(F&&);
-    ...
-    template<class F, Allocator Alloc> function(allocator_arg_t, const Alloc&, F); 
-    template<class F, Allocator Alloc> function(allocator_arg_t, const Alloc&, F&&);
-    ...
-    template<class F> 
-      requires CopyConstructible<F> && Callable<F, ArgTypes..> 
-            && Convertible<Callable<F, ArgTypes...>::result_type 
-      function& operator=(F); 
-    template<class F> 
-      requires CopyConstructible<F> && Callable<F, ArgTypes...> 
-            && Convertible<Callable<F, ArgTypes...>::result_type, R> 
-      function& operator=(F&&);
-    ...
-};
+
        unary_negate<P>(std::move(pred))
 
        
-
-
-
-
-
-
-
        
-
        1071. is_bind_expression should derive from integral_constant<bool>
        
-
        Section: 20.7.12.1.1 [func.bind.isbind] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-19  Last modified: 2009-05-31
        
-
        View all issues with Open status.
        
-
        Discussion:
        
-
 
        
-Class template is_bind_expression 20.7.12.1.1 [func.bind.isbind]:
+in the Returns clause ?]
 
        
-
-
        namespace std {
-  template<class T> struct is_bind_expression {
-    static const bool value = see below;
-  };
-}
-
        
+
        2. 
+
      2. 
+
        template <AdaptableBinaryFunction P>
+requires Predicate< P, P::first_argument_type, P::second_argument_type >
+binary_negate<P> not2(const P& pred);
+template <AdaptableBinaryFunction P>
+requires Predicate< P, P::first_argument_type, P::second_argument_type >
+binary_negate<P> not2(P&& pred);
+
        
 
        
-is_bind_expression should derive from std::integral_constant<bool> like
-other similar trait types.
+-5- Returns: binary_negate<P>(pred).
 
        
-
-
        [
-Daniel adds:
-]
        
-
-
        
-We need the same thing for the trait is_placeholder as well.
-
        
-
        [
-2009-03-22 Daniel provided wording.
-]
        
-
-
-
        [
-Batavia (2009-05):
-]
        
-
-
        
 
        
-We recommend this be deferred until after the next Committee Draft is issued.
+[Don't we want a move call for the second overload as in
 
        
+
        binary_negate<P>(std::move(pred))
+
        
 
        
-Move to Open.
+in the Returns clause ?]
 
        
+
        3. 
+
      
+
      5. 
+
    
 
    
 
 
    [
-2009-05-31 Peter adds:
+Batavia (2009-05):
 ]
    
 
-
 
    
 
    
-I am opposed to the proposed resolution and to the premise of the issue
-in general. The traits's default definitions should NOT derive from
-integral_constant, because this is harmful, as it misleads people into
-thinking that is_bind_expression<E> always derives from
-integral_constant, whereas it may not.
+There is concern that complicating the solution
+to preserve the ABI seems unnecessary,
+since we're not in general preserving the ABI.
 
    
 
    
-is_bind_expression and is_placeholder allow user
-specializations, and in fact, this is their primary purpose. Such user
-specializations may not derive from integral_constant, and the
-places where is_bind_expression and is_placeholder are
-used intentionally do not require such derivation.
+We would prefer a separate paper consolidating all Clause 20
+issues that are for the purpose of providing constrained versions
+of the existing facilities.
 
    
 
    
-The long-term approach here is to switch to
-BindExpression<E> and Placeholder<P>
-explicit concepts, of course, but until that happens, I say leave them
-alone.
+Move to Open.
 
    
 
    
 
 
-
 
    Proposed resolution:
    
-
      
-
    1. 
 
      
-In 20.7.12.1.1 [func.bind.isbind] change as indicated:
+Add new concepts where appropriate::
 
      
-
      namespace std {
- template<class T> struct is_bind_expression : integral_constant<bool, see below> { };{
-   static const bool value = see below;
- };
+
+
      auto concept AdaptableUnaryFunction< typename X > {
+  typename X::result_type;
+  typename X::argument_type;
+}
+
+auto concept AdaptableBinaryFunction< typename X > {
+  typename X::result_type;
+  typename X::first_argument_type;
+  typename X::second_argument_type;
 }
 
      
-
      2. 
-
    2. 
+
 
      
-In 20.7.12.1.1 [func.bind.isbind]/2 change as indicated:
+Revise as follows:
 
      
-
      static const bool value;
-
      
+
+
      
+Base 20.7.3 [base] (Only change is constrained Result)
+
      
+
 
      
--2- true if T is a type returned from bind, false otherwise.
-  If T is a type returned from bind, is_bind_expression<T> shall
-be publicly derived from
-        integral_constant<bool, true>, otherwise it shall be
-publicly derived from
-          integral_constant<bool, false>.
-
      
-
      
-
      3. 
-
    3. 
 
      
-In 20.7.12.1.2 [func.bind.isplace] change as indicated:
+-1-  The following classes are provided to simplify the typedefs of the
+argument and result types:
 
      
-
      namespace std {
- template<class T> struct is_placeholder : integral_constant<int, see below> { };{
-   static const int value = see below;
- };
+
      namespace std {
+  template <class Arg, class ReturnType Result>
+  struct unary_function {
+     typedef Arg    argument_type;
+     typedef Result result_type;
+  };
+
+  template <class Arg1, class Arg2, class ReturnType Result>
+  struct binary_function {
+     typedef Arg1   first_argument_type;
+     typedef Arg2   second_argument_type;
+     typedef Result result_type;
+  };
 }
 
      
-
      4. 
-
    4. 
+
 
      
-In 20.7.12.1.2 [func.bind.isplace]/2 change as indicated:
+Negators 20.7.11 [negators]:
 
      
-
      static const int value;
+
+
      
+
      
+-1- Negators not1 and not2 take a unary and a binary predicate,
+respectively, and return their complements (5.3.1).
+
      
+
+
      template <class AdaptableUnaryFunction Predicate>
+  requires Predicate< P, P::argument_type >
+  class unary_negate
+    : public unary_function<typename Predicate::argument_type,bool> {
+  public:
+    unary_negate(const unary_negate & ) = default;
+    unary_negate(unary_negate && );
+
+    requires CopyConstructible< P >
+       explicit unary_negate(const Predicate& pred); 
+    requires MoveConstructible< P >
+       explicit unary_negate(Predicate && pred);
+
+    bool operator()(const typename Predicate::argument_type& x) const;
+  };
 
      
 
      
--2- value is J if T is the type of std::placeholders::_J, 0 otherwise.
-  If T is the type of std::placeholders::_J, is_placeholder<T>
-shall be publicly
-          derived from integral_constant<int, J> otherwise it shall
-be publicly derived
-          from integral_constant<int, 0>.
+-2 operator() returns !pred(x).
+
      
+
+
      template <class Predicate>
+  unary_negate<Predicate> not1(const Predicate&amp; pred);
+template <class Predicate>
+  unary_negate<Predicate> not1(Predicate&& pred);
+
      
+
      
+-3-  Returns: unary_negate<Predicate>(pred).
 
      
+
+
      template <class AdaptableBinaryFunction Predicate >
+  requires Predicate< P, P::first_argument_type, P::second_argument_type >
+  class binary_negate
+    : public binary_function<typename Predicate::first_argument_type,
+                              typename Predicate::second_argument_type, bool> {
+  public:
+    biary_negate(const binary_negate & ) = default;
+    binary_negate(binary_negate && );
+
+    requires CopyConstructible< P >
+       explicit binary_negate(const Predicate& pred);
+    requires MoveConstructible< P >
+       explicit binary_negate(const Predicate& pred);
+
+    bool operator()(const typename Predicate::first_argument_type& x,
+                    const typename Predicate::second_argument_type& y) const;
+  };
+
      
+
      
+-4- operator() returns !pred(x,y).
 
      
-
      5. 
-
    
+
+
    template <class Predicate>
+  binary_negate<Predicate> not2(const Predicate& pred);
+template <class Predicate>
+  binary_negate<Predicate> not2(Predicate&& pred);
+
    
+
+
    
+-5- Returns: binary_negate<Predicate>(pred).
+
    
+
    
+
 
 
 
 
 
 
    
-
    1072. Is std::hash a constrained template or not?
    
-
    Section: 20.7.17 [unord.hash] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-19  Last modified: 2009-05-23
    
-
    View other active issues in [unord.hash].
    
-
    View all other issues in [unord.hash].
    
+
    1079. UK-265: RandomAccessIterator's operator- has nonsensical effects clause
    
+
    Section: 24.2.6 [random.access.iterators] Status: Open
+ Submitter: Doug Gregor Opened: 2009-03-20  Last modified: 2009-03-22
    
+
    View other active issues in [random.access.iterators].
    
+
    View all other issues in [random.access.iterators].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
+
    Addresses UK 265
    
 
+
    UK-265:
    
 
    
-Is std::hash a constrained template or not?
-
    
-
    
-According to Class template hash 20.7.17 [unord.hash], the definition is:
+This effects clause is nonesense. It looks more like an axiom stating
+equivalence, and certainly an effects clause cannot change the state of
+two arguments passed by const reference
 
    
 
-
    template <class T>
-struct hash : public std::unary_function<T, std::size_t> {
-  std::size_t operator()(T val) const;
-};
-
    
+
+
+
    Proposed resolution:
    
+
+
    Modify 24.2.6 [random.access.iterators]p7-9 as follows:
    
+
+
    difference_type operator-(const X& a, const X& b);
+
    
+
      
+  
    1. Precondition: there exists a value n of
+  difference_type such that a == b + n.
      2. 
+  
    2. Effects: b == a + (b - a)
      3. 
+  
    3. Returns: (a < b) ? distance(a,b) :
+  -distance(b,a)n
      4. 
+
    
+
    
+
+
+
+
+
+
    
+
    1088. Response to UK 342
    
+
    Section: 30.6.4 [futures.promise] Status: Open
+ Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-03-22
    
+
    View other active issues in [futures.promise].
    
+
    View all other issues in [futures.promise].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
+
    Addresses UK 342
    
 
 
    
-And so unconstrained.
-
    
-
    
-According to the <functional> synopsis in p2 Function objects
-20.7 [function.objects] the template is declared as:
+std::promise is missing a non-member overload of swap. This is
+inconsistent with other types that provide a swap member function.
 
    
 
-
    template <ReferentType T> struct hash;
-
    
-
 
    
-which would make hash a constrained template.
+Add a non-member overload void swap(promise&& x,promise&& y){ x.swap(y); }
 
    
 
 
    [
-2009-03-22 Daniel provided wording.
+Summit:
 ]
    
 
+
    
+Create an issue. Move to review, attention: Howard. Detlef will also
+look into it.
+
    
 
 
    [
-Batavia (2009-05):
+Post Summit Daniel provided wording.
 ]
    
 
-
    
-
    
-Alisdair is not certain that Daniel's proposed resolution is sufficient,
-and recommends we leave the hash template unconstrained for now.
-
    
-
    
-Recommend that the Project Editor make the constrained declaration consistent
-with the definition in order to make the Working Paper internally consistent,
-and that the issue then be revisited.
-
    
-
    
-Move to Open.
-
    
-
    
 
 
 
    Proposed resolution:
    
-
-
    
-[To the editor: This resolution is merge-compatible to the
-resolution of 1078]
-
    
-
 
      
 
    1. 
 
      
-In 20.7 [function.objects]/2, header <functional> synopsis, change as indicated:
-
      
-
-
      // 20.6.17, hash function base template:
-template <ReferentType T> struct hash; // undefined
-
      
-
      2. 
-
    2. 
-
      
-In 20.7.17 [unord.hash]/1 change as indicated:
+In 30.6.4 [futures.promise], before p.1, immediately after class template
+promise add:
 
      
-
      namespace std {
- template <class T>
- struct hash : public std::unary_function<T, std::size_t> {
- std::size_t operator()(T val) const;
- };
- template <ReferentType T> struct hash; // undefined
-}
+
      
+template <class R>
+void swap(promise<R>& x, promise<R>& y);
+
 
      
 
      3. 
 
    3. 
 
      
-In 20.7.17 [unord.hash]/2 change as indicated:
+Change 30.6.4 [futures.promise]/10 as indicated (to fix a circular definition):
 
      
-
 
      
--2-  For all library-provided specializations, the template
-instantiation hash<T>
-  shall provide a public operator() with return type std::size_t to
-satisfy the concept
-  requirement Callable<const hash<T>, const T&>. If T is an object
-type or reference to
-  object, hash<T> shall be publicly derived from
-std::unary_function<T, std::size_t>.
-   The return value of operator() is unspecified, except that
-equal arguments
-  shall yield the same result. operator() shall not throw exceptions.
+
      
+-10- Effects: swap(*this, other)Swaps the associated state
+of *this and other
+
      
+
      
+Throws: Nothing.
+
      
 
      
 
      4. 
 
    4. 
 
      
-In 18.7 [support.rtti]/1, header <typeinfo> synopsis change as indicated:
+After the last paragraph in 30.6.4 [futures.promise] add the following
+prototype description:
 
      
-
      namespace std {
-  class type_info;
-  class type_index;
-  template <classReferentType T> struct hash;
-
      
-
      5. 
-
    
-
-
-
-
-
-
    
-
    1073. Declaration of allocator_arg should be constexpr
    
-
    Section: 20.8 [memory] Status: Tentatively Ready
- Submitter: Alisdair Meredith Opened: 2009-03-19  Last modified: 2009-05-23
    
-
    View other active issues in [memory].
    
-
    View all other issues in [memory].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
-
+
    
+template <class R>
+void swap(promise<R>& x, promise<R>& y);
+
    
+
    
 
    
-Declaration of allocator_arg should be constexpr to ensure constant
-initialization.
+Effects: x.swap(y)
 
    
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-We agree with the proposed resolution.  Move to Tentatively Ready.
-
    
-
-
-
    Proposed resolution:
    
 
    
-Change 20.8 [memory] p2:
+Throws: Nothing.
 
    
+
    
+
    
+
 
-
    // 20.8.1, allocator argument tag
-struct allocator_arg_t { };
-constexpr allocator_arg_t allocator_arg = allocator_arg_t();
-
    
+
 
 
 
@@ -31842,484 +25682,554 @@ constexpr allocator_arg_t allocator_arg = allocator_arg_t();
 
 
 
    
-
    1074. concept map broken by N2840
    
-
    Section: 20.8.3 [allocator.element.concepts] Status: Tentatively NAD
- Submitter: Alisdair Meredith Opened: 2009-03-19  Last modified: 2009-05-23
    
-
    View all issues with Tentatively NAD status.
    
+
    1089. Response to JP 76
    
+
    Section: 30 [thread] Status: Open
+ Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-08-02
    
+
    View all other issues in [thread].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
+
    Addresses JP 76
    
 
 
    
-p7 Allocator-related element concepts 20.8.3 [allocator.element.concepts]
+A description for "Throws: Nothing." are not unified.
 
    
 
 
    
-The changes to the AllocatableElement concept mean this concept_map
-specialization no longer matches the original concept:
+At the part without throw, "Throws: Nothing." should be described.
 
    
 
-
    template <Allocator Alloc, class T, class ... Args>
-  requires HasConstructor<T, Args...>
-    concept_map AllocatableElement<Alloc, T, Args&&...> {
-      void construct_element(Alloc& a, T* t, Args&&... args) {
-        Alloc::rebind<T>(a).construct(t, forward(args)...);
-      }
-    }
-
    
+
    
+Add "Throws: Nothing." to the following.
+
    
+
+
      
+
    • 
+30.3.1.6 [thread.thread.static] p1
+
      • 
+
    • 
+30.4.3.1 [thread.lock.guard] p4
+
      • 
+
    • 
+30.4.3.2.1 [thread.lock.unique.cons] p6
+
      • 
+
    • 
+30.5.1 [thread.condition.condvar] p7 and p8
+
      • 
+
    • 
+30.5.2 [thread.condition.condvarany] p6, p7, p19, p21 and p25
+
      • 
+
    
 
 
    [
-2009-03-23 Pablo adds:
+Summit:
 ]
    
 
-
 
    
-Actually, this is incorrect,
-N2840
-says. "In section 
-20.8.3 [allocator.element.concepts] paragraph 8, modify the definition of the
-AllocatableElement concept and eliminate the related concept map:" but
-then neglects to include the red-lined text of the concept map that was
-to be eliminated. Pete also missed this, but I caught it he asked me to
-review his edits.  Pete's updated WP removes the concept map entirely,
-which was the original intent.  The issue is, therefore, moot.  Note, as
-per my presentation of
-N2840
-in summit, construct() no longer has a
-default implementation.  This regrettable fact was deemed (by David
-Abrahams, Doug, and myself) to be preferable to the complexity of
-providing a default implementation that would not under-constrain a more
-restrictive allocator (like the scoped allocators).
+Pass on to editor.
 
    
 
 
    [
-2009-05-01 Daniel adds:
+Post Summit:  Editor declares this non-editorial.
 ]
    
 
-
    
-
    
-it seems to me that #1074 should be resolved as a NAD, because the
-current WP has already removed the previous AllocatableElement concept map.
-It introduced auto concept AllocatableElement instead, but as of
-20.8.3 [allocator.element.concepts]/7 this guy contains now
-
    
-
    requires FreeStoreAllocatable<T>;
-void Alloc::construct(T*, Args&&...);
-
    
-
    
 
 
    [
-Batavia (2009-05):
+2009-08-01 Howard provided wording:
 ]
    
 
+
 
    
+
 
    
-The affected code is no longer part of the Working Draft.
-
    
-
    
-Move to NAD.
+The definition of "Throws: Nothing." that I added is probably going to
+be controversial, but I beg you to consider it seriously.
 
    
-
    
-
 
-
    Proposed resolution:
    
+
    
 
    
-Change 20.8.3 [allocator.element.concepts]:
+In C++ there are three "flow control" options for a function:
 
    
 
-
    template <Allocator Alloc, class T, class ... Args>
-  requires HasConstructor<T, Args...>
-    concept_map AllocatableElement<Alloc, T, Args&&...> {
-      void construct_element(Alloc& a, T* t, Args&&... args) {
-        Alloc::rebind<T>(a).construct(t, forward(args)...);
-      }
-    }
-
    
-
-
-
-
-
-
-
    
-
    1075. Response to US 65, US 74.1
    
-
    Section: 20 [utilities], 23 [containers] Status: Open
- Submitter: Alan Talbot Opened: 2009-03-20  Last modified: 2009-06-10
    
-
    View all other issues in [utilities].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    Addresses US 65 and US 74.1
    
-
-
    US 65:
    
+
      
+
    1. 
+It can return, either with a value, or with void.
+
      2. 
+
    2. 
+It can call a function which never returns, such as std::exit or
+std::terminate.
+
      3. 
+
    3. 
+It can throw an exception.
+
      4. 
+
    
 
-
    
-Scoped allocators and allocator propagation traits add a small amount of
-utility at the cost of a great deal of machinery. The machinery is user
-visible, and it extends to library components that don't have any
-obvious connection to allocators, including basic concepts and simple
-components like pair and tuple.
+The above list can be abbreviated with:
 
-
    Suggested resolution:
    
+
      
+
    1. Returns.
      2. 
+
    2. Ends program.
      3. 
+
    3. Throws exception.
      4. 
+
    
 
 
    
-Sketch of proposed resolution: Eliminate scoped allocators, replace
-allocator propagation traits with a simple uniform rule (e.g. always
-propagate on copy and move), remove all mention of allocators from
-components that don't explicitly allocate memory (e.g. pair), and adjust
-container interfaces to reflect this simplification.
-
    
-
    
-Components that I propose eliminating include HasAllocatorType,
-is_scoped_allocator, allocator_propagation_map, scoped_allocator_adaptor,
-and ConstructibleAsElement.
+In general a function can have the behavior of any of these 3, or any combination
+of any of these three, depending upon run time data.
 
    
-
    
 
-
    US 74.1:
    
+
      
+
    1. R
      2. 
+
    2. E
      3. 
+
    3. T
      4. 
+
    4. RE
      5. 
+
    5. RT
      6. 
+
    6. ET
      7. 
+
    7. RET
      8. 
+
    
 
-
    
-
    
-Scoped allocators represent a poor trade-off for standardization, since
-(1) scoped-allocator--aware containers can be implemented outside the
-C++ standard library but used with its algorithms, (2) scoped
-allocators only benefit a tiny proportion of the C++ community
-(since few C++ programmers even use today's allocators), and (3) all C++
-users, especially the vast majority of the C++ community that won't ever
-use scoped allocators are forced to cope with the interface complexity
-introduced by scoped allocators.
-
    
 
    
-In essence, the larger community will suffer to support a very small
-subset of the community who can already implement their own
-data structures outside of the standard library. Therefore, scoped
-allocators should be removed from the working paper.
+A function with no throw spec, and no documentation, is in general a RET
+function.  It may return, it may end the program, or it may throw.  When we
+specify a function with an empty throw spec:
 
    
+
+
    void f() throw();
+
    
+
 
    
-Some evidence of the complexity introduced by scoped allocators:
+We are saying that f() is an RE function:  It may return or end
+the program, but it will not throw.
 
    
-
    
+
 
    
-20.3.3 [pairs], 20.5 [tuple]: Large increase in the
-number of pair and tuple constructors.
+I posit that there are very few places in the library half of the standard
+where we intend for functions to be able to end the program (call terminate).
+And none of those places where we do say terminate could be called,
+do we currently say "Throws: Nothing.".
 
    
+
 
    
-23 [containers]: Confusing "AllocatableElement" requirements throughout.
+I believe that if we define "Throws: Nothing." to mean R,
+we will both clarify many, many places in the standard, and give us a
+good rationale for choosing between "Throws: Nothing." (R)
+and throw() (RE) in the future.  Indeed, this may give us motivation
+to change several throw()s to "Throws: Nothing.".
 
    
 
    
-
    Suggested resolution:
    
 
 
    
-Remove support for scoped allocators from the working paper. This
-includes at least the following changes:
+I did not add the following changes as JP 76 requested as I believe we want to
+allow these functions to throw:
 
    
 
 
    
 
    
-Remove 20.8.3 [allocator.element.concepts]
-
    
-
    
-Remove 20.8.7 [allocator.adaptor]
+Add a paragraph under 30.4.3.1 [thread.lock.guard] p4:
 
    
+
+
    explicit lock_guard(mutex_type& m);
+
    
+
+
    
+Throws: Nothing.
+
    
+
    
+
 
    
-Remove 20.8.10 [construct.element]
+Add a paragraph under 30.4.3.2.1 [thread.lock.unique.cons] p6:
 
    
+
+
    explicit unique_lock(mutex_type& m);
+
    
+
+
    
+Throws: Nothing.
+
    
+
    
+
 
    
-In Clause 23 [containers]: replace requirements naming the
-AllocatableElement concept with requirements naming CopyConstructible,
-MoveConstructible, DefaultConstructible, or Constructible, as
-appropriate.
+Add a paragraph under 30.5.2 [thread.condition.condvarany] p19, p21 and p25:
 
    
+
+
    template <class Lock, class Rep, class Period> 
+  bool wait_for(Lock& lock, const chrono::duration<Rep, Period>& rel_time);
+
    
+
+
    
+Throws: Nothing.
+
    
 
    
 
+
    template <class Lock, class Duration, class Predicate> 
+  bool wait_until(Lock& lock, const chrono::time_point<Clock, Duration>& rel_time, Predicate pred);
+
    
+
+
    
+Throws: Nothing.
+
    
 
    
 
-
    [
-Post Summit Alan moved from NAD to Open.
-]
    
+
    template <class Lock, class Rep, class Period, class Predicate> 
+  bool wait_for(Lock& lock, const chrono::duration<Rep, Period>& rel_time, Predicate pred);
+
    
 
+
    
+Throws: Nothing.
+
    
+
    
+
+
    
+
+
    
 
-
    [
-2009-05-15 Ganesh adds:
-]
    
 
 
+
+
+
    Proposed resolution:
    
+
    
+Add a paragraph after 17.5.1.4 [structure.specifications] p4:
+
    
+
 
    
 
    
-The requirement AllocatableElement should not be replaced with
-Constructible on the emplace_xxx() functions as suggested. In the
-one-parameter case the Constructible requirement is not satisfied when
-the constructor is explicit (as per 14.10.2.1 [concept.map.fct], twelfth
-bullet) but we do want to allow explicit constructors in emplace, as the
-following example shows:
+-3- Descriptions of function semantics contain the following elements
+(as appropriate):158
+
    
+
      
+
    • ...
      • 
+
    • 
+Throws: any exceptions thrown by the function, and the conditions
+that would cause the exception
+
      • 
+
    • ...
      • 
+
    
+
+
    
+-4- For non-reserved replacement and handler functions, ...
+
    
+
+
    
+A "Throws: Nothing." element indicates that the function shall
+return ordinarily, and not via an exception.  This element also
+indicates that the function shall return. [Note: This
+differs from an empty throw specification which may cause a function to
+call unexpected and subsequently terminate. —
+end note]
+
    
+
    
+
+
    
+Add a paragraph under 30.3.1.6 [thread.thread.static] p1:
 
    
 
-
    vector<shared_ptr<int>> v;
-v.emplace_back(new int); // should be allowed
-
    
+
    unsigned hardware_concurrency();
+
    
 
 
    
-If the issue is accepted and scoped allocators are removed, I suggest to
-add a new pair of concepts to 20.2.7 [concept.construct], namely:
+-1- Returns: ...
 
    
 
-
    auto concept HasExplicitConstructor<typename T, typename... Args> {
- explicit T::T(Args...);
-}
-
-auto concept ExplicitConstructible<typename T, typename... Args>
- : HasExplicitConstructor<T, Args...>, NothrowDestructible<T>
-{ }
-
    
+
    
+Throws: Nothing.
+
    
+
    
 
 
    
-We should then use ExplicitConstructible as the requirement for all
-emplace_xxx() member functions.
+Add a paragraph under 30.5.1 [thread.condition.condvar] p7 and p8:
 
    
+
+
    
 
    
-For coherence and consistency with the similar concepts
-Convertible/ExplicitlyConvertible, we might also consider changing
-Constructible to:
+[Informational, not to be incluced in the WP: The POSIX spec allows only:
 
    
+
    
+
    [EINVAL]
    
+
    The value cond does not refer to an initialized condition variable. — end informational]
    
+
    
 
-
    auto concept Constructible<typename T, typename... Args>
- : HasConstructor<T, Args...>, ExplicitConstructible<T, Args...>
-{ }
-
    
+
    void notify_one();
+
    
 
 
    
-Moreover, all emplace-related concepts in 23.2.6 [container.concepts]
-should also use ExplicitConstructible instead of Constructible in the
-definitions of their axioms. In fact the concepts in 23.2.6 [container.concepts] should be
-corrected even if the issue is not accepted.
-
    
-
    
-On the other hand, if the issue is not accepted, the scoped allocator
-adaptors should be fixed because the following code:
+-7- Effects: ...
 
    
 
-
    template <typename T> using scoped_allocator = scoped_allocator_adaptor<allocator<T>>;
+
    
+Throws: Nothing.
+
    
+
    
 
-vector<shared_ptr<int>, scoped_allocator<shared_ptr<int>>> v;
-v.emplace_back(new int); // ops! doesn't compile
-
    
+
    void notify_all();
+
    
 
 
    
-doesn't compile, as the member function construct() of the scoped
-allocator requires non-explicit constructors through concept
-ConstructibleWithAllocator. Fixing that is not difficult but probably
-more work than it's worth and is therefore, IMHO, one more reason in
-support of the complete removal of scoped allocators.
+-8- Effects: ...
 
    
-
    
 
-
    [
-2009-06-09 Alan adds:
-]
    
+
    
+Throws: Nothing.
+
    
+
    
 
 
-
    
-
    
-I reopened this issue because I did not think that these National Body
-comments were adequately addressed by marking them NAD. My understanding
-is that something can be marked NAD if it is clearly a misunderstanding
-or trivial, but a substantive issue that has any technical merit
-requires a disposition that addresses the concerns.
-
    
 
    
-The notes in the NB comment list (US 65 & US 74.1) say that:
+Add a paragraph under 30.5.2 [thread.condition.condvarany] p6 and p7:
 
    
-
      
-
    1. 
-this issue has not introduced any new arguments not previously discussed,
-
      2. 
-
    2. 
-the vote (4-9-3) was not a consensus for removing scoped allocators,
-
      3. 
-
    3. 
-the issue is resolved by
-N2840.
-
      4. 
-
    
+
+
    
+
    void notify_one();
+
    
+
 
    
-My opinion is:
+-6- Effects: ...
 
    
-
      
-
    1. 
-there are new arguments in both comments regarding concepts (which were
-not present in the library when the scoped allocator proposal was voted
-in),
-
      2. 
-
    2. 
-the vote was clearly not a consensus for removal, but just saying there
-was a vote does not provide a rationale,
-
      3. 
-
    3. 
-I do not believe that N2840 addresses these comments (although it does
-many other things and was voted in with strong approval).
-
      4. 
-
    
+
+
    
+Throws: Nothing.
+
    
+
    
+
+
    void notify_all();
+
    
 
 
    
-My motivation to open the issue was to ensure that the NB comments were
-adequately addressed in a way that would not risk a "no" vote on our
-FCD. If there are responses to the technical concerns raised, then
-perhaps they should be recorded. If the members of the NB who authored
-the comments are satisfied with N2840 and the other disposition remarks
-in the comment list, then I am sure they will say so. In either case,
-this issue can be closed very quickly in Frankfurt, and hopefully will
-have helped make us more confident of approval with little effort. If in
-fact there is controversy, my thought is that it is better to know now
-rather than later so there is more time to deal with it.
+-7- Effects: ...
 
    
-
    
 
+
    
+Throws: Nothing.
+
    
+
    
 
 
-
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1076. unary/binary_negate need constraining and move support
    
-
    Section: 20.7.11 [negators] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-03-20  Last modified: 2009-05-23
    
+
    1090. Missing description of packaged_task member swap,  missing non-member swap
    
+
    Section: 30.6.7 [futures.task] Status: Open
+ Submitter: Daniel Krügler Opened: 2009-03-22  Last modified: 2009-05-24
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-The class templates unary/binary_negate need constraining and move support.
+Class template packaged_task in 30.6.7 [futures.task] shows a member swap
+declaration, but misses to
+document it's effects (No prototype provided). Further on this class
+misses to provide a non-member
+swap.
 
    
+
+
    [
+Batavia (2009-05):
+]
    
+
+
    
 
    
-Ideally these classes would be deprecated, allowing unary/binary_function to
-also be deprecated.  However, until a generic negate adaptor is introduced
-that can negate any Callable type, they must be supported so should be
-constrained.  Likewise, they should be movable, and support adopting a
-move-only predicate type.
+Alisdair notes that paragraph 2 of the proposed resolution has already been
+applied in the current Working Draft.
 
    
 
    
-In order to preserve ABI compatibility, new rvalue overloads are supplied in
-preference to changing the existing pass-by-const-ref to pass-by-value.
+We note a pending future-related paper by Detlef;
+we would like to wait for this paper before proceeding.
 
    
 
    
-Do not consider the issue of forwarding mutable lvalues at this point,
-although remain open to another issue on the topic.
+Move to Open.
 
    
+
    
 
 
    [
-2009-05-01 Daniel adds:
+2009-05-24 Daniel removed part 2 of the proposed resolution.
 ]
    
 
-
    
-
    
-IMO the currently proposed resolution needs some updates
-because it is ill-formed at several places:
-
    
 
+
+
    Proposed resolution:
    
 
      
 
    1. 
 
      
-In concept AdaptableUnaryFunction change
+In 30.6.7 [futures.task], immediately after the definition of class
+template packaged_task add:
 
      
-
      typename X::result_type;
-typename X::argument_type;
+
      
+template<class R, class... Argtypes>
+void swap(packaged_task<R(ArgTypes...)>&, packaged_task<R(ArgTypes...)>&);
+
 
      
+
      2. 
+
    
+
+
      
+
    1. 
 
      
-to
+In 30.6.7 [futures.task], immediately after operator= prototype
+description (After p. 8) add:
 
      
-
      Returnable result_type = typename X::result_type;
-typename argument_type = typename X::argument_type;
-
      
+
      void swap(packaged_task& other);
+
      
+
      
+
      
+Effects: Swaps the associated state of *this and other.
+
      
+
      
+Throws: Nothing.
+
      
+
      
+
      
+
      2. 
+
    2. 
 
      
-[The replacement "Returnable result_type" instead of "typename
-result_type" is non-editorial, but maybe you prefer that as well]
+At the end of 30.6.7 [futures.task] (after p. 20), add add the following
+prototype description:
 
      
+
+
      
+template<class R, class... Argtypes>
+void swap(packaged_task<R(ArgTypes...)>& x, packaged_task<R(ArgTypes...)>& y);
+
      
+
      
+
      
+Effects: x.swap(y)
+
      
+
      
+Throws: Nothing.
+
      
+
      
+
      
 
      3. 
-
    3. 
+
    
+
+
+
+
+
+
    
+
    1091. Multimap description confusing
    
+
    Section: 23.4.2.2 [multimap.modifiers] Status: Review
+ Submitter: LWG Opened: 2009-03-22  Last modified: 2009-07-04
    
+
    View all issues with Review status.
    
+
    Discussion:
    
+
+
    Addresses UK 246
    
 
    
-In concept AdaptableBinaryFunction change
+The content of this sub-clause is purely trying to describe in words the
+effect of the requires clauses on these operations, now that we have
+Concepts. As such, the description is more confusing than the signature
+itself. The semantic for these functions is adequately covered in the
+requirements tables in 23.2.4 [associative.reqmts].
+
    
+
+
    [
+Beman adds:
+]
    
+
+
+
    
+Pete is clearly right that
+this one is technical rather than editorial.
+
    
+
+
    [
+Batavia (2009-05):
+]
    
+
+
    
+
    
+We agree with the proposed resolution.
 
    
-
    typename X::result_type;
-typename X::first_argument_type;
-typename X::second_argument_type;
-
    
 
    
-to
+Move to Review.
 
    
-
    Returnable result_type = typename X::result_type;
-typename first_argument_type = typename X::first_argument_type;
-typename second_argument_type = typename X::second_argument_type;
-
    
+
    
+
+
+
    Proposed resolution:
    
 
    
-[The replacement "Returnable result_type" instead of "typename
-result_type" is non-editorial, but maybe you prefer that as well.]
+Strike 23.4.2.2 [multimap.modifiers] entirely
+(but do NOT strike these signatures from the class template definition!).
 
    
-
 
-
  • 
+
+
+
+
+
    
+
    1093. Multiple definitions for random_shuffle algorithm
    
+
    Section: 25.4.12 [alg.random.shuffle] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-03-22  Last modified: 2009-07-28
    
+
    View all other issues in [alg.random.shuffle].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
+
 
    
-In class unary/binary_function
+There are a couple of issues with the declaration of the random_shuffle
+algorithm accepting a random number engine.
 
    
-
      
+
+
        
 
      1. 
-I suggest to change "ReturnType" to "Returnable" in both cases.
+The Iterators must be shuffle iterators, yet this requirement is missing.
 
        2. 
 
      2. 
-I think you want to replace the remaining occurrences of "Predicate" by "P"
-(in both classes in copy/move from a predicate)
+The RandomNumberEngine concept is now provided by the random number
+library
+(n2836)
+and the placeholder should be removed.
 
        3. 
 
      
-
-
    1. 
+
+
      [
+2009-05-02 Daniel adds:
+]
      
+
+
+
      
 
      
-I think you need to change the proposed signatures of not1 and not2, because
-they would still remain unconstrained: To make them constrained at least a
-single requirement needs to be added to enable requirement implication. This
-could be done via a dummy ("requires True<true>") or just explicit as follows:
+this issue completes adding necessary requirement to the
+third new random_shuffle overload. The current suggestion is:
 
      
-
        
-
      1. 
-
        template <AdaptableUnaryFunction P>
-requires Predicate< P, P::argument_type>
-unary_negate<P> not1(const P&& pred);
-template <AdaptableUnaryFunction P>
-requires Predicate< P, P::argument_type >
-unary_negate<P> not1(P&& pred);
-
        
-
        
--3- Returns: unary_negate<P>(pred).
-
        
-
        
+
+
        template<RandomAccessIterator Iter, UniformRandomNumberGenerator Rand>
+requires ShuffleIterator<Iter>
+void random_shuffle(Iter first, Iter last, Rand&& g);
+
        
+
 
        
-[Don't we want a move call for the second overload as in
+IMO this is still insufficient and I suggest to add the requirement
 
        
-
        unary_negate<P>(std::move(pred))
+
        Convertible<Rand::result_type, Iter::difference_type>
 
        
 
        
-in the Returns clause ?]
+to the list (as the two other overloads already have).
 
        
-
        2. 
-
      2. 
-
        template <AdaptableBinaryFunction P>
-requires Predicate< P, P::first_argument_type, P::second_argument_type >
-binary_negate<P> not2(const P& pred);
-template <AdaptableBinaryFunction P>
-requires Predicate< P, P::first_argument_type, P::second_argument_type >
-binary_negate<P> not2(P&& pred);
-
        
+
 
        
--5- Returns: binary_negate<P>(pred).
+Rationale:
 
        
+
+
        
 
        
-[Don't we want a move call for the second overload as in
+Its true that this third overload is somewhat different from the remaining
+two. Nevertheless we know from UniformRandomNumberGenerator, that
+it's result_type is an integral type and that it satisfies
+UnsignedIntegralLike<result_type>.
 
        
-
        binary_negate<P>(std::move(pred))
-
        
 
        
-in the Returns clause ?]
+To realize it's designated task, the algorithm has to invoke the
+Callable aspect of g and needs to perform some algebra involving
+it's min()/max() limits to compute another index value that
+at this point is converted into Iter::difference_type. This is so,
+because 24.2.6 [random.access.iterators] uses this type as argument
+of it's algebraic operators. Alternatively consider the equivalent
+iterator algorithms in 24.4 [iterator.operations] with the same result.
 
        
-
        3. 
-
      
-
      2. 
-
    
+
    
+This argument leads us to the conclusion that we also need
+Convertible<Rand::result_type, Iter::difference_type> here.
+
    
+
    • 
+
 
    
 
 
    [
@@ -32328,768 +26238,828 @@ Batavia (2009-05):
 
 
    
 
    
-There is concern that complicating the solution
-to preserve the ABI seems unnecessary,
-since we're not in general preserving the ABI.
+Alisdair notes that point (ii) has already been addressed.
 
    
 
    
-We would prefer a separate paper consolidating all Clause 20
-issues that are for the purpose of providing constrained versions
-of the existing facilities.
+We agree with the proposed resolution to point (i)
+with Daniel's added requirement.
 
    
 
    
-Move to Open.
+Move to Review.
 
    
 
    
 
+
    [
+2009-06-05 Daniel updated proposed wording as recommended in Batavia.
+]
    
+
+
+
    [
+2009-07-28 Alisdair adds:
+]
    
+
+
+
    
+Revert to Open, with a note there is consensus on direction but the
+wording needs updating to reflect removal of concepts.
+
    
+
 
 
    Proposed resolution:
    
 
    
-Add new concepts where appropriate::
+Change in 25.2 [algorithms.syn] and 25.4.12 [alg.random.shuffle]:
 
    
 
-
    auto concept AdaptableUnaryFunction< typename X > {
-  typename X::result_type;
-  typename X::argument_type;
-}
-
-auto concept AdaptableBinaryFunction< typename X > {
-  typename X::result_type;
-  typename X::first_argument_type;
-  typename X::second_argument_type;
-}
+
    concept UniformRandomNumberGenerator<typename Rand> { }
+template<RandomAccessIterator Iter, UniformRandomNumberGenerator Rand>
+  requires ShuffleIterator<Iter> &&
+  Convertible<Rand::result_type, Iter::difference_type>
+  void random_shuffle(Iter first, Iter last, Rand&& g);
 
    
 
+
+
+
+
+
+
    
+
    1094. Response to JP 65 and JP 66
    
+
    Section: 27.5.4.3 [iostate.flags] Status: Review
+ Submitter: P.J. Plauger Opened: 2009-03-24  Last modified: 2009-05-23
    
+
    View all other issues in [iostate.flags].
    
+
    View all issues with Review status.
    
+
    Discussion:
    
+
    Addresses JP 65 and JP 66
    
+
 
    
-Revise as follows:
+Switch from "unspecified-bool-type" to "explicit operator bool() const". 
 
    
 
 
    
-Base 20.7.3 [base] (Only change is constrained Result)
+Replace operator unspecified-bool-type() const;" with explicit operator bool() const;
 
    
 
+
    [
+Batavia (2009-05):
+]
    
+
 
    
+We agree with the proposed resolution.
+Move to Review.
+
    
+
+
+
    Proposed resolution:
    
 
    
--1-  The following classes are provided to simplify the typedefs of the
-argument and result types:
+Change the synopis in 27.5.4 [ios]:
 
    
-
    namespace std {
-  template <class Arg, class ReturnType Result>
-  struct unary_function {
-     typedef Arg    argument_type;
-     typedef Result result_type;
-  };
 
-  template <class Arg1, class Arg2, class ReturnType Result>
-  struct binary_function {
-     typedef Arg1   first_argument_type;
-     typedef Arg2   second_argument_type;
-     typedef Result result_type;
-  };
-}
+
    explicit operator unspecified-bool-type bool() const;
 
    
 
 
    
-Negators 20.7.11 [negators]:
+Change 27.5.4.3 [iostate.flags]:
 
    
 
+
    explicit operator unspecified-bool-type bool() const;
+
    
+
 
    
 
    
--1- Negators not1 and not2 take a unary and a binary predicate,
-respectively, and return their complements (5.3.1).
+-1- Returns: !fail() If fail() then a value that will evaluate
+false in a boolean context; otherwise a value that will evaluate true in
+a boolean context. The value type returned shall not be convertible to
+int.
+
    
+
    
+[Note: This conversion can be used in contexts where a bool is expected
+(e.g., an if condition); however, implicit conversions (e.g.,
+to int) that can occur with bool are not allowed,
+eliminating some sources of user error. One possible implementation
+choice for this type is pointer-to-member. -- end note]
 
    
+
    
+
    
 
-
    template <class AdaptableUnaryFunction Predicate>
-  requires Predicate< P, P::argument_type >
-  class unary_negate
-    : public unary_function<typename Predicate::argument_type,bool> {
-  public:
-    unary_negate(const unary_negate & ) = default;
-    unary_negate(unary_negate && );
 
-    requires CopyConstructible< P >
-       explicit unary_negate(const Predicate& pred); 
-    requires MoveConstructible< P >
-       explicit unary_negate(Predicate && pred);
 
-    bool operator()(const typename Predicate::argument_type& x) const;
-  };
-
    
-
    
--2 operator() returns !pred(x).
-
    
 
-
    template <class Predicate>
-  unary_negate<Predicate> not1(const Predicate&amp; pred);
-template <class Predicate>
-  unary_negate<Predicate> not1(Predicate&& pred);
-
    
+
+
+
+
    
+
    1095. Shared objects and the library wording unclear
    
+
    Section: 17.6.3.10 [res.on.objects] Status: Review
+ Submitter: Beman Dawes Opened: 2009-03-27  Last modified: 2009-05-23
    
+
    View all issues with Review status.
    
+
    Discussion:
    
+
    
+N2775,
+Small library thread-safety revisions, among other changes, removed a note from
+17.6.3.10 [res.on.objects] that read:
+
    
+
 
    
--3-  Returns: unary_negate<Predicate>(pred).
+[Note: This prohibition against concurrent non-const access means that
+modifying an object of a standard library type shared between threads
+without using a locking mechanism may result in a data race. --end note.]
 
    
 
-
    template <class AdaptableBinaryFunction Predicate >
-  requires Predicate< P, P::first_argument_type, P::second_argument_type >
-  class binary_negate
-    : public binary_function<typename Predicate::first_argument_type,
-                              typename Predicate::second_argument_type, bool> {
-  public:
-    biary_negate(const binary_negate & ) = default;
-    binary_negate(binary_negate && );
+
    
+That resulted in wording which is technically correct but can only be
+understood by reading the lengthy and complex 17.6.4.7 [res.on.data.races]
+Data race avoidance. This has the effect of making
+17.6.3.10 [res.on.objects] unclear, and has already resulted in a query
+to the LWG reflector. See c++std-lib-23194.
+
    
 
-    requires CopyConstructible< P >
-       explicit binary_negate(const Predicate& pred);
-    requires MoveConstructible< P >
-       explicit binary_negate(const Predicate& pred);
+
    [
+Batavia (2009-05):
+]
    
 
-    bool operator()(const typename Predicate::first_argument_type& x,
-                    const typename Predicate::second_argument_type& y) const;
-  };
-
    
 
    
--4- operator() returns !pred(x,y).
+
    
+The proposed wording seems to need a bit of tweaking
+("really bad idea" isn't quite up to standardese).
+We would like feedback
+as to whether the original Note's removal was intentional.
+
    
+
    
+Change the phrase "is a really bad idea"
+to "risks undefined behavior" and
+move to Review status.
+
    
 
    
 
-
    template <class Predicate>
-  binary_negate<Predicate> not2(const Predicate& pred);
-template <class Predicate>
-  binary_negate<Predicate> not2(Predicate&& pred);
-
    
+
+
    Proposed resolution:
    
+
    
+Change 17.6.3.10 [res.on.objects] as indicated:
+
    
 
 
    
--5- Returns: binary_negate<Predicate>(pred).
-
    
+
    
+The behavior of a program is undefined if calls to standard library
+functions from different threads may introduce a data race. The
+conditions under which this may occur are specified in 17.6.4.7.
+
    
+
    
+[Note: Thus modifying an object of a standard library type shared between
+threads risks undefined behavior unless objects of the type are explicitly
+specified as being sharable without data races or the user supplies a
+locking mechanism. --end note]
+
    
 
    
 
 
 
 
 
-
 
    
-
    1077. Nonesense tuple declarations
    
-
    Section: 20.5.2 [tuple.tuple] Status: Tentatively NAD Editorial
- Submitter: Pete Becker Opened: 2009-03-20  Last modified: 2009-05-23
    
-
    View other active issues in [tuple.tuple].
    
-
    View all other issues in [tuple.tuple].
    
-
    View all issues with Tentatively NAD Editorial status.
    
+
    1097. #define __STDCPP_THREADS
    
+
    Section: 18.2 [support.types] Status: Review
+ Submitter: Jens Maurer Opened: 2009-04-03  Last modified: 2009-05-23
    
+
    View all other issues in [support.types].
    
+
    View all issues with Review status.
    
 
    Discussion:
    
+
    Addresses DE 18
    
+
 
    
-Class template tuple 20.5.2 [tuple.tuple]:
+Freestanding implementations do not (necessarily) have
+  support for multiple threads (see 1.10 [intro.multithread]).
+  Applications and libraries may want to optimize for the
+  absence of threads.  I therefore propose a preprocessor
+  macro to indicate whether multiple threads can occur.
 
    
 
-
    template <class... UTypes>
-  requires Constructible<Types, const UTypes&>...
-template <class... UTypes>
-  requires Constructible<Types, RvalueOf<UTypes>::type>...
-
    
-
 
    
-Somebody needs to look at this and say what it should be.
+There is ample prior implementation experience for this
+  feature with various spellings of the macro name.  For
+  example, gcc implicitly defines _REENTRANT
+  if multi-threading support is selected on the compiler
+  command-line.
 
    
 
-
    [
-2009-03-21 Daniel provided wording.
-]
    
+
    
+While this is submitted as a library issue, it may be more
+  appropriate to add the macro in 16.8 cpp.predefined in the
+  core language.
+
    
 
+
    
+See also
+N2693.
+
    
 
 
    [
 Batavia (2009-05):
 ]
    
 
 
    
-The resolution looks correct; move to NAD Editorial.
+
    
+We agree with the issue, and believe it is properly a library issue.
+
    
+
    
+We prefer that the macro be conditionally defined
+as part of the <thread> header.
+
    
+
    
+Move to Review.
+
    
 
    
 
 
 
    Proposed resolution:
    
 
    
-In 20.5.2 [tuple.tuple], class tuple, change as indicated:
+Insert a new subsection before 18.2 [support.types], entitled
+"Feature Macros" (support.macros):
 
    
-
-
    template <class... UTypes>
-  requires Constructible<Types, const UTypes&>...
-  tuple(const pair<UTypes...>&);
-template <class... UTypes>
-  requires Constructible<Types, RvalueOf<UTypes>::type>...
-  tuple(pair<UTypes...>&&);
-
    
-
+
    
 
    
-[NB.: The corresponding prototypes do already exist in 20.5.2.1 [tuple.cnstr]/7+8]
+The standard library defines the following macros; no explicit
+prior inclusion of any header file is necessary.
 
    
+
    
+
    
+
    __STDCPP_THREADS
    
+
    
+The macro __STDCPP_THREADS shall be defined if and only if a
+    program can have more than one thread of execution (1.10 [intro.multithread]).
+If the macro is defined, it shall have the same
+    value as the predefined macro __cplusplus (16.8 [cpp.predefined]).
+
    
+
    
+
    
+
    
+
 
 
 
 
 
 
    
-
    1078. DE-17: Remove class type_index
    
-
    Section: 18.7.2 [type.index] Status: Open
- Submitter: Doug Gregor Opened: 2009-03-20  Last modified: 2009-03-31
    
+
    1098. definition of get_pointer_safety()
    
+
    Section: 20.8.10.7 [util.dynamic.safety] Status: Open
+ Submitter: Jens Maurer Opened: 2009-04-03  Last modified: 2009-05-23
    
+
    View all other issues in [util.dynamic.safety].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
-
-
    Addresses DE 17
    
+
    Addresses DE 18
    
 
 
    
-DE-17: 
+ In 20.8.10.7 [util.dynamic.safety], get_pointer_safety() purports
+to define behavior for
+ non-safely derived pointers (3.7.4.3 [basic.stc.dynamic.safety]).  However,
+ the cited core-language section in paragraph 4 specifies undefined behavior
+ for the use of such pointer values.  This seems an unfortunate near-contradiction.
+ I suggest to specify the term relaxed pointer safety in
+ the core language section and refer to it from the library description.
+ This issue deals with the library part, the corresponding core issue (c++std-core-13940)
+ deals with the core modifications.
 
    
+
 
    
-The class type_index should be removed; it provides no additional
-functionality beyond providing appropriate concept maps.
+See also
+N2693.
 
    
 
 
    [
-2009-03-31 Peter adds:
+Batavia (2009-05):
 ]
    
 
-
 
    
 
    
-It is not true, in principle, that std::type_index provides no  utility
-compared to bare std::type_info*.
+We recommend if this issue is to be moved,
+the issue be moved concurrently with the cited Core issue.
+
    
+
    
+We agree with the intent of the proposed resolution.
+We would like input from garbage collection specialists.
 
    
 
    
-std::type_index can avoid the lifetime issues with type_info when  the
-DLL that has produced the type_info object is unloaded. A raw
-type_info* does not, and cannot, provide any protection in this  case.
-A type_index can (if the implementor so chooses) because it  can wrap a
-smart (counted or even cloning) pointer to the type_info  data that is
-needed for name() and before() to work.
+Move to Open.
 
    
 
    
 
 
 
 
    Proposed resolution:
    
-
    Modify the header <typeinfo> synopsis in 
-  18.7 [support.rtti]p1 as follows:
    
-
-
    namespace std { 
-  class type_info; 
-  class type_index;
-  template <class T> struct hash;
-  template<> struct hash<type_indexconst type_info *> : public std::unary_function<type_indexconst type_info *, size_t> {
-    size_t operator()(type_indexconst type_info * indext) const;
-  };
-  concept_map LessThanComparable<const type_info *> see below
-  class bad_cast; 
-  class bad_typeid;
-}
-
    
+
    
+In 20.8.10.7 [util.dynamic.safety] p16, replace the description of
+get_pointer_safety() with:
+
    
 
-
    Add the following new subsection
    
 
    
 
    
-18.7.1.1 Template specialization hash<const type_info *>
-[type.info.hash]
    
-
-
    size_t operator()(const type_info *x) const;
-
    
-
      
-
    1. Returns: x->hash_code()
      2. 
-
    
-
    
+pointer_safety get_pointer_safety();
+
    
+
    
+
    
+Returns: an enumeration value indicating the implementation's treatment
+of pointers that are not safely derived (3.7.4.3). Returns
+pointer_safety::relaxed if pointers that are not safely derived will be
+treated the same as pointers that are safely derived for the duration of
+the program. Returns pointer_safety::preferred if pointers that are not
+safely derived will be treated the same as pointers that are safely
+derived for the duration of the program but allows the implementation to
+hint that it could be desirable to avoid dereferencing pointers that are
+not safely derived as described. [Example: pointer_safety::preferred
+might be returned to detect if a leak detector is running to avoid
+spurious leak reports. -- end note] Returns pointer_safety::strict if
+pointers that are not safely derived might be treated differently than
+pointers that are safely derived.
+
    
+
    
+Returns: Returns pointer_safety::strict if the implementation has
+   strict pointer safety (3.7.4.3 [basic.stc.dynamic.safety]). It is
+   implementation-defined whether get_pointer_safety returns
+   pointer_safety::relaxed or pointer_safety::preferred if the
+   implementation has relaxed pointer safety
+   (3.7.4.3 [basic.stc.dynamic.safety]).Footnote
+
    
 
- 
    Add the following new subsection
    
- 
    
-
    18.7.1.2 type_info concept map [type.info.concepts]
    
+
    
+Throws: nothing
+
    
 
+
    
+Footnote) pointer_safety::preferred might be returned to indicate to the
+   program that a leak detector is running so that the program can avoid
+   spurious leak reports.
+
+
    
 
-
    concept_map LessThanComparable<const type_info *> {
-  bool operator<(const type_info *x, const type_info *y) { return x->before(*y); }
-  bool operator<=(const type_info *x, const type_info *y) { return !y->before(*x); }
-  bool operator>(const type_info *x, const type_info *y) { return y->before(*x); }
-  bool operator>=(const type_info *x, const type_info *y) { return !x->before(*y); }
-}
-
    
-
      
-  
    1. Note: provides a well-defined ordering among
-  type_info const pointers, which makes such pointers
-  usable in associative containers (23.4).
      2. 
-
    
 
    
-
-
    Remove section 18.7.2 [type.index]
    
+
    
 
 
 
 
 
 
    
-
    1079. UK-265: RandomAccessIterator's operator- has nonsensical effects clause
    
-
    Section: 24.2.6 [random.access.iterators] Status: Open
- Submitter: Doug Gregor Opened: 2009-03-20  Last modified: 2009-03-22
    
-
    View other active issues in [random.access.iterators].
    
-
    View all other issues in [random.access.iterators].
    
+
    1099. Various issues
    
+
    Section: 17 [library] Status: Open
+ Submitter: David Abrahams Opened: 2009-03-21  Last modified: 2009-05-23
    
+
    View other active issues in [library].
    
+
    View all other issues in [library].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
-
    Addresses UK 265
    
-
-
    UK-265:
    
 
    
-This effects clause is nonesense. It looks more like an axiom stating
-equivalence, and certainly an effects clause cannot change the state of
-two arguments passed by const reference
+Notes
+
    
+
    
+
    
+[2009-03-21 Sat] p. 535 at the top we need MoveConstructible V1,
+MoveConstructible V2 (where V1,V2 are defined on 539).  Also make_tuple
+on 550
+
    
+
    
+[2009-03-21 Sat] p1183 thread ctor, and in general, we need a way to
+talk about "copiable from generalized rvalue ref argument" for cases
+where we're going to forward and copy.  
+
    
+
    
+
    
+   This issue may well be quite large.  Language in para 4 about "if
+   an lvalue" is wrong because types aren't expressions.
+
    
+
    
+   p1199, call_once has all the same issues.
+
    
+
    
+
    
+[2009-03-21 Sat] p869 InputIterator pointer type should not be required
+to be convertible to const value_type*, rather it needs to have a
+operator-> of its own that can be used for the value type.
+
    
+
    
+[2009-03-21 Sat] p818 stack has the same problem with default ctor.
+
    
+
    
+[2009-03-21 Sat] p816 priority_queue has the same sorts of problems as queue, only more so
 
    
-
-
-
-
    Proposed resolution:
    
-
-
    Modify 24.2.6 [random.access.iterators]p7-9 as follows:
    
-
-
    difference_type operator-(const X& a, const X& b);
+
       requires MoveConstructible<Cont> 
+     explicit priority_queue(const Compare& x = Compare(), Cont&& = Cont()); 
 
    
-
      
-  
    1. Precondition: there exists a value n of
-  difference_type such that a == b + n.
      2. 
-  
    2. Effects: b == a + (b - a)
      3. 
-  
    3. Returns: (a < b) ? distance(a,b) :
-  -distance(b,a)n
      4. 
-
    
+
    
+   Don't require MoveConstructible when default constructing Cont.
+   Also missing semantics for move ctor.
+
    
 
    
+
    
+ [2009-03-21 Sat] Why are Allocators required to be CopyConstructible as
+ opposed to MoveConstructible?
+
    
+
    
+ [2009-03-21 Sat] p813 queue needs a separate default ctor (Cont needn't
+ be MoveConstructible).  No documented semantics for move c'tor.  Or
+ *any* of its 7 ctors!
+
    
+
    
+ [2009-03-21 Sat] std::array should have constructors for C++0x,
+ consequently must consider move construction.
+
    
 
+
    [
+2009-05-01 Daniel adds:
+]
    
 
 
+
    
+This could be done as part of 1035, which already handles
+deviation of std::array from container tables.
+
    
 
-
-
    
-
    1080. Concept ArithmeticLike should provide explicit boolean  conversion
    
-
    Section: 20.2.13 [concept.arithmetic] Status: Review
- Submitter: Daniel Krügler Opened: 2009-03-21  Last modified: 2009-05-23
    
-
    View all issues with Review status.
    
-
    Discussion:
    
 
    
-Astonishingly, the current concept ArithmeticLike as specified in
-20.2.13 [concept.arithmetic] does not provide explicit conversion
-to bool although this is a common property of arithmetic types
-(4.12 [conv.bool]). Recent proposals that introduced such types
-(integers of arbitrary precision,
-n2143,
-decimals
-n2732
-indirectly
-via conversion to long long) also took care of such a feature.
+ [2009-03-21 Sat] p622 all messed up.
 
    
+
    
 
    
-Adding such an explicit conversion associated function would also
-partly solve a currently invalid effects clause in library, which bases
-on this property, 24.2.6 [random.access.iterators]/2:
+   para 8 "implementation-defined" is the wrong term; should be "see
+   below" or something.  
 
    
-
    { difference_type m = n;
- if (m >= 0) while (m--) ++r;
- else while (m++) --r;
- return r; }
-
    
-
 
    
-Both while-loops take advantage of a contextual conversion to bool
-(Another problem is that the >= comparison uses the no
-longer supported existing implicit conversion from int to IntegralLike).
+   para 12 "will be selected" doesn't make any sense because we're not
+   talking about actual arg types.
 
    
-
-Original proposed resolution:
-
      
-
    1. 
 
      
-In 20.2.13 [concept.arithmetic], add to the list of less refined
-concepts one further concept:
+   paras 9-13 need to be totally rewritten for concepts.
 
      
+
    
 
-
    concept ArithmeticLike<typename T>
-  : Regular<T>, LessThanComparable<T>, HasUnaryPlus<T>, HasNegate<T>,
-    HasPlus<T, T>, HasMinus<T, T>, HasMultiply<T, T>, HasDivide<T, T>,
-    HasPreincrement<T>, HasPostincrement<T>, HasPredecrement<T>,
-    HasPostdecrement<T>,
-    HasPlusAssign<T, const T&>, HasMinusAssign<T, const T&>,
-    HasMultiplyAssign<T, const T&>,
-    HasDivideAssign<T, const T&>, ExplicitlyConvertible<T, bool> {
-
    
-
-
  • 
 
    
-In 24.2.6 [random.access.iterators]/2 change the current effects clause
-as indicated [The proposed insertion fixes the problem that the previous
-implicit construction from integrals has been changed to an explicit
-constructor]:
+ [2009-03-21 Sat] Null pointer comparisons (p587) have all become
+ unconstrained.  Need to fix that
 
    
-
    { difference_type m = n;
- if (m >= difference_type(0)) while (m--) ++r;
- else while (m++) --r;
- return r; }
-
    
-
    • 
-
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
 
    
-We agree that arithmetic types ought be convertible to bool,
-and we therefore agree with the proposed resolution's paragraph 1.
+ [2009-03-21 Sat] mem_fun_t etc. definition doesn't match declaration.
+  We think CopyConstructible is the right reqt.
 
    
 
    
-We do not agree that the cited effects clause is invalid,
-as it expresses intent rather than specific code.
+ make_pair needs Constructible<V1, T1&&> requirements!
 
    
 
    
-Move to Review, pending input from concepts experts.
+ make_tuple needs something similar
 
    
-
    
-
-
-
-
    Proposed resolution:
    
 
    
-In 20.2.13 [concept.arithmetic], add to the list of less refined
-concepts one further concept:
+ tuple bug in synopsis:
 
    
+
       template <class... UTypes>
+   requires Constructible<Types, const UTypes&>...
+   template <class... UTypes>
+   requires Constructible<Types, RvalueOf<UTypes>::type>...
+
    
+
    
+   Note: removal of MoveConstructible requirements in std::function makes
+   these routines unconstrained!
+
    
+
    
 
-
    concept ArithmeticLike<typename T>
-  : Regular<T>, LessThanComparable<T>, HasUnaryPlus<T>, HasNegate<T>,
-    HasPlus<T, T>, HasMinus<T, T>, HasMultiply<T, T>, HasDivide<T, T>,
-    HasPreincrement<T>, HasPostincrement<T>, HasPredecrement<T>,
-    HasPostdecrement<T>,
-    HasPlusAssign<T, const T&>, HasMinusAssign<T, const T&>,
-    HasMultiplyAssign<T, const T&>,
-    HasDivideAssign<T, const T&>, ExplicitlyConvertible<T, bool> {
-
    
-
-
-
+
    [
+2009-05-02 Daniel adds:
+]
    
 
 
-
    
-
    1081. Response to UK 216
    
-
    Section: 21 [strings] Status: Open
- Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-03-22
    
-
    View all other issues in [strings].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    Addresses UK 216, JP 46, JP 48
    
+
    
+This part of the issue is already covered by 1077.
+
    
 
 
    
-All the containers use concepts for their iterator usage, exect for
-basic_string. This needs fixing.
+ these unique_ptr constructors are broken [ I think this is covered in "p622 all messed up" ]
 
    
-
+
     unique_ptr(pointer p, implementation-defined d);
+ unique_ptr(pointer p, implementation-defined d);
+
    
 
    
-Use concepts for iterator template parameters throughout the chapter.
+ multimap range constructor should not have MoveConstructible<value_type> requirement.
 
    
+
    
+   same with insert(..., P&&); multiset has the same issue, as do
+   unordered_multiset and unordered_multimap. Review these!
+
    
+
+
    
 
 
    [
-Summit:
+Batavia (2009-05):
 ]
    
 
 
    
-NB comments to be handled by Dave Abrahams and Howard Hinnant with
-advice from PJP: UK216 (which duplicates) JP46, JP48. JP46 supplies
-extensive proposed wording; start there.
+Move to Open, pending proposed wording from Dave for further review.
 
    
 
 
 
    Proposed resolution:
    
+
    
+
    
 
 
 
 
 
 
    
-
    1082. Response to JP 49
    
-
    Section: 22 [localization] Status: Open
- Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-03-22
    
-
    View other active issues in [localization].
    
-
    View all other issues in [localization].
    
-
    View all issues with Open status.
    
+
    1100. auto_ptr to unique_ptr conversion
    
+
    Section: 20.8.9.2.1 [unique.ptr.single.ctor] Status: Review
+ Submitter: Howard Hinnant Opened: 2009-04-25  Last modified: 2009-08-01
    
+
    View other active issues in [unique.ptr.single.ctor].
    
+
    View all other issues in [unique.ptr.single.ctor].
    
+
    View all issues with Review status.
    
 
    Discussion:
    
-
    Addresses JP 49
    
-
 
    
-codecvt does not use concept. For example, create CodeConvert
-concept and change as follows.
+Message c++std-lib-23182 led to a discussion in which several people
+expressed interest in being able to convert an auto_ptr to a
+unique_ptr without the need to call release.  Below is
+wording to accomplish this.
 
    
 
-
    template<CodeConvert Codecvt, class Elem = wchar_t>
-  class wstring_convert {
-
    
+
    [
+Batavia (2009-05):
+]
    
+
+
    
+
    
+Pete believes it not a good idea to separate parts of a class's definition.
+Therefore, if we do this,
+it should be part of unique-ptr's specification.
+
    
+
    
+Alisdair believes the lvalue overload may be not necessary.
+
    
+
    
+Marc believes it is more than just sugar,
+as it does ease the transition to unique-ptr.
+
    
+
    
+We agree with the resolution as presented.
+Move to Tentatively Ready.
+
    
+
    
 
 
    [
-Summit:
+2009-07 Frankfurt
 ]
    
 
+
 
    
-To be handled by Howard Hinnant, Dave Abrahams, Martin Sebor, PJ Plauger.
+Moved from Tentatively Ready to Open only because the wording needs to be
+tweaked for concepts removal.
 
    
 
+
    [
+2009-08-01 Howard deconceptifies wording:
+]
    
 
-
    Proposed resolution:
    
 
+
    
+I also moved the change from D.9 [depr.auto.ptr]
+to 20.8.9.2 [unique.ptr.single] per the Editor's request
+in Batavia (as long as I was making changes anyway).  Set back
+to Review.
+
    
 
 
 
+
    Proposed resolution:
    
+
    
+Add to 20.8.9.2 [unique.ptr.single]:
+
    
 
-
    
-
    1083. Response to JP 52, 53
    
-
    Section: 22 [localization] Status: Open
- Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-03-22
    
-
    View other active issues in [localization].
    
-
    View all other issues in [localization].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    Addresses JP 52, JP 53
    
+
    template <class T, class D>
+class unique_ptr
+{
+public:
+    template <class U>
+      unique_ptr(auto_ptr<U>& u);
+    template <class U>
+      unique_ptr(auto_ptr<U>&& u);
+};
+
    
 
 
    
-InputIterator does not use concept.
+Add to 20.8.9.2.1 [unique.ptr.single.ctor]:
 
    
 
+
    template <class U>
+  unique_ptr(auto_ptr<U>& u);
+template <class U>
+  unique_ptr(auto_ptr<U>&& u);
+
    
+
    
 
    
-OutputIterator does not use concept.
+Effects: Constructs a unique_ptr with u.release().
 
    
 
 
    
-Comments include proposed wording.
+Postconditions: get() ==  the value u.get() had before
+the construciton, modulo any required offset adjustments resulting from the cast from
+U* to T*.  u.get() == nullptr.
 
    
 
-
    [
-Summit:
-]
    
+
    
+Throws: nothing.
+
    
 
-
    
-To be handled by Howard Hinnant, Dave Abrahams, Martin Sebor, PJ Plauger.
+
    
+Remarks: U* shall be implicitly convertible to T* and
+D shall be the same type as default_delete<T>, else these
+constructors shall not participate in overload resolution.
+
    
+
    
 
    
 
 
-
    Proposed resolution:
    
-
 
 
 
 
 
    
-
    1084. Response to UK 250
    
-
    Section: 24.2.4 [forward.iterators] Status: Open
- Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-06-09
    
-
    View all other issues in [forward.iterators].
    
-
    View all issues with Open status.
    
+
    1102. std::vector's reallocation policy still unclear
    
+
    Section: 23.3.6.2 [vector.capacity] Status: Review
+ Submitter: Daniel Krügler Opened: 2009-04-20  Last modified: 2009-05-23
    
+
    View all other issues in [vector.capacity].
    
+
    View all issues with Review status.
    
 
    Discussion:
    
-
    Addresses UK 250
    
-
 
    
-A default implementation should be supplied for the post-increment
-operator to simplify implementation of iterators by users.
+I have the impression that even the wording of current draft
+N2857
+does insufficiently express the intent of vector's
+reallocation strategy. This has produced not too old library
+implementations which release memory in the clear() function
+and even modern articles about C++ programming cultivate
+the belief that clear is allowed to do exactly this. A typical
+example is something like this:
 
    
 
+
    const int buf_size = ...;
+std::vector<T> buf(buf_size);
+for (int i = 0; i < some_condition; ++i) {
+  buf.resize(buf_size);
+  write_or_read_data(buf.data());
+  buf.clear(); // Ensure that the next round get's 'zeroed' elements
+}
+
    
 
    
-Copy the Effects clause into the concept description as the default
-implementation. Assumes a default value for postincrement_result
+where still the myth is ubiquitous that buf might be
+allowed to reallocate it's memory *inside* the for loop.
+
    
+
    
+IMO the problem is due to the fact, that
 
    
 
-
    [
-Summit:
-]
    
-
+
      
+
    1. 
+the actual memory-reallocation stability of std::vector
+is explained in 23.3.6.2 [vector.capacity]/3 and /6 which
+are describing just the effects of the reserve
+function, but in many examples (like above) there
+is no explicit call to reserve involved. Further-more
+23.3.6.2 [vector.capacity]/6 does only mention insertions
+and never mentions the consequences of erasing
+elements.
+
      2. 
+
    2. 
+
      
+the effects clause of std::vector's erase overloads in
+23.3.6.4 [vector.modifiers]/4 is silent about capacity changes. This
+easily causes a misunderstanding, because the counter
+parting insert functions described in 23.3.6.4 [vector.modifiers]/2
+explicitly say, that
+
      
 
      
-Howard will open an issue.
+Causes reallocation if the new size is greater than the
+old capacity. If no reallocation happens, all the iterators
+and references before the insertion point remain valid.
 
      
+
      
+It requires a complex argumentation chain about four
+different places in the standard to provide the - possibly
+weak - proof that calling clear() also does never change
+the capacity of the std::vector container. Since std::vector
+is the de-facto replacement of C99's dynamic arrays this
+type is near to a built-in type and it's specification should
+be clear enough that usual programmers can trust their
+own reading.
+
      
+
      3. 
+
    
 
 
    [
-2009-06-07 Daniel adds:
+Batavia (2009-05):
 ]
    
 
-
 
    
-This issue cannot currently be resolved as suggested, because
-that would render auto-detection of the return type
-postincrement_result invalid, see 14.10.2.2 [concept.map.assoc]/4+5. The
-best fix would be to add a default type to that associated type, but
-unfortunately any default type will prevent auto-deduction of types of
-associated functions as quoted above. A corresponding core issue
-is in preparation.
+
    
+Bill believes paragraph 1 of the proposed resolution is unnecessary
+because it is already implied (even if tortuously) by the current wording.
+
    
+
    
+Move to Review.
+
    
 
    
 
 
 
    Proposed resolution:
    
 
    [
-This wording assumes the acceptance of UK 251 / 1009.  Both
-wordings change the same paragraphs.
+This is a minimum version. I also
+suggest that the wording explaining the allocation strategy
+of std::vector in 23.3.6.2 [vector.capacity]/3 and /6 is moved into
+a separate sub paragraph of 23.3.6.2 [vector.capacity] before
+any of the prototype's are discussed, but I cannot provide
+reasonable wording changes now
 ]
    
 
 
+
      
+
    1. 
 
      
-Change 24.2.4 [forward.iterators]:
+Change 23.3.6.2 [vector.capacity]/6 as follows:
 
      
-
 
      
-
      concept ForwardIterator<typename X> : InputIterator<X>, Regular<X> { 
-
-  MoveConstructible postincrement_result;
-  requires HasDereference<postincrement_result>
-        && Convertible<HasDereference<postincrement_result>::result_type, const value_type&>;
-
-  postincrement_result operator++(X& r, int); {
-     X tmp = r;
-     ++r;
-     return tmp;
-  }
-
-  axiom MultiPass(X a, X b) { 
-    if (a == b) *a == *b; 
-    if (a == b) ++a == ++b; 
-  } 
-}
-
      
-
-
-
-
-
-
-
      
-
      1085. Response to UK 258
      
-
      Section: 24.2.5 [bidirectional.iterators] Status: Open
- Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-06-09
      
-
      View all other issues in [bidirectional.iterators].
      
-
      View all issues with Open status.
      
-
      Discussion:
      
-
      Addresses UK 258
      
-
-
      
-A default implementation should be supplied for the post-decrement
-operator to simplify implementation of iterators by users.
-
      
-
+It is guaranteed that no reallocation takes place during
+insertions or erasures that happen after a call
+to reserve() until the time when an insertion would make
+the size of the vector greater than the value of capacity().
+
    
+
+
  • 
 
    
-Copy the Effects clause into the concept description as the default
-implementation. Assumes a default value for postincrement_result
+Change 23.3.6.4 [vector.modifiers]/4 as follows:
 
    
-
-
    [
-Summit:
-]
    
-
 
    
-Howard will open an issue.
+Effects: The capacity shall remain unchanged and no reallocation shall
+happen.
+Invalidates iterators and references at or after the point
+of the erase.
 
    
-
-
    [
-2009-06-07 Daniel adds:
-]
    
+
    • 
+
 
 
-
    
-This issue cannot currently be resolved as suggested, because
-that would render auto-detection of the return type
-postdecrement_result invalid, see 1084.
-
    
 
 
-
    Proposed resolution:
    
 
+
    
+
    1104. basic_ios::move should accept lvalues
    
+
    Section: 27.5.4.2 [basic.ios.members] Status: Review
+ Submitter: Howard Hinnant Opened: 2009-04-25  Last modified: 2009-05-23
    
+
    View other active issues in [basic.ios.members].
    
+
    View all other issues in [basic.ios.members].
    
+
    View all issues with Review status.
    
+
    Discussion:
    
 
    
-Change 24.2.5 [bidirectional.iterators]:
+With the rvalue reference changes in
+N2844
+basic_ios::move no longer has the most convenient signature:
 
    
 
-
    
-
    concept BidirectionalIterator<typename X> : ForwardIterator<X> { 
-  MoveConstructible postdecrement_result; 
-  requires HasDereference<postdecrement_result> 
-        && Convertible<HasDereference<postdecrement_result>::result_type, const value_type&> 
-        && Convertible<postdecrement_result, const X&>; 
-  X& operator--(X&); 
-  postdecrement_result operator--(X& r, int); {
-     X tmp = r;
-     --r;
-     return tmp;
-  }
-}
+
    void move(basic_ios&& rhs);
 
    
 
-
-
-
-
-
-
    
-
    1086. Response to UK 284
    
-
    Section: 24.6 [stream.iterators] Status: Open
- Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-03-22
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    Addresses UK 284
    
-
 
    
-The stream iterators need constraining with concepts/requrires clauses.
+This signature should be changed to accept lvalues.  It does not need to be
+overloaded to accept rvalues.  This is a special case that only derived clients
+will see.  The generic move still needs to accept rvalues.
 
    
 
 
    [
-Summit:
+Batavia (2009-05):
 ]
    
 
 
    
-We agree. To be handled by Howard, Martin and PJ.
-
    
-
-
-
    Proposed resolution:
    
-
-
-
-
-
-
    
-
    1087. Response to UK 301
    
-
    Section: 25.4.5 [alg.replace] Status: Review
- Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-06-11
    
-
    View other active issues in [alg.replace].
    
-
    View all other issues in [alg.replace].
    
-
    View all issues with Review status.
    
-
    Discussion:
    
-
    Addresses UK 301
    
-
 
    
-replace and replace_if have the requirement: OutputIterator<Iter,
-Iter::reference> Which implies they need to copy some values in the
-range the algorithm is iterating over. This is not however the case, the
-only thing that happens is const T&s might be copied over existing
-elements (hence the OutputIterator<Iter, const T&>.
+Tom prefers, on general principles, to provide both overloads.
+Alisdair agrees.
+
    
+
    
+Howard points out that there is no backward compatibility issue
+as this is new to C++0X.
 
    
-
 
    
-Remove OutputIterator<Iter, Iter::reference> from replace
-and replace_if.
+We agree that both overloads should be provided,
+and Howard will provide the additional wording.
+Move to Open.
 
    
+
    
 
 
    [
-Summit:
+2009-05-23 Howard adds:
 ]
    
 
+
 
    
-We agree. To be handled by Howard.
+Added overload, moved to Review.
 
    
 
 
+
 
    Proposed resolution:
    
 
    
-Change in 25.2 [algorithms.syn] and 25.4.5 [alg.replace]:
+Add a signature to the existing prototype in the synopsis of 27.5.4 [ios]
+and in 27.5.4.2 [basic.ios.members]:
 
    
 
-
    template<ForwardIterator Iter, class T> 
-  requires OutputIterator<Iter, Iter::reference> 
-        && OutputIterator<Iter, const T&> 
-        && HasEqualTo<Iter::value_type, T> 
-  void replace(Iter first, Iter last, 
-               const T& old_value, const T& new_value); 
-
-template<ForwardIterator Iter, Predicate<auto, Iter::value_type> Pred, class T> 
-  requires OutputIterator<Iter, Iter::reference> 
-        && OutputIterator<Iter, const T&> 
-        && CopyConstructible<Pred> 
-  void replace_if(Iter first, Iter last,
-                  Pred pred, const T& new_value);
+
    void move(basic_ios& rhs);
+void move(basic_ios&& rhs);
 
    
 
 
@@ -33097,87 +27067,78 @@ template<ForwardIterator Iter, Predicate<auto, Iter::value_type> Pred,
 
 
 
    
-
    1088. Response to UK 342
    
-
    Section: 30.6.6 [futures.promise] Status: Open
- Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-03-22
    
-
    View other active issues in [futures.promise].
    
-
    View all other issues in [futures.promise].
    
+
    1106. Multiple exceptions from connected shared_future::get()?
    
+
    Section: 30.6.6 [future.shared_future] Status: Open
+ Submitter: Thomas J. Gritzan Opened: 2009-04-03  Last modified: 2009-05-23
    
+
    View other active issues in [future.shared_future].
    
+
    View all other issues in [future.shared_future].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
-
    Addresses UK 342
    
-
 
    
-std::promise is missing a non-member overload of swap. This is
-inconsistent with other types that provide a swap member function.
+It is not clear, if multiple threads are waiting in a 
+shared_future::get() call, if each will rethrow the stored exception.
 
    
-
 
    
-Add a non-member overload void swap(promise&& x,promise&& y){ x.swap(y); }
+Paragraph 9 reads: 
 
    
-
-
    [
-Summit:
-]
    
-
 
    
-Create an issue. Move to review, attention: Howard. Detlef will also
-look into it.
+Throws: the stored exception, if an exception was stored and not 
+retrieved before.
 
    
+
    
+The "not retrieved before" suggests that only one exception is thrown, 
+but one exception for each call to get() is needed, and multiple calls 
+to get() even on the same shared_future object seem to be allowed. 
+
    
+
    
+I suggest removing "and not retrieved before" from the Throws paragraph. 
+I recommend adding a note that explains that multiple calls on get() are 
+allowed, and each call would result in an exception if an exception was 
+stored. 
+
    
 
 
    [
-Post Summit Daniel provided wording.
+Batavia (2009-05):
 ]
    
 
-
-
-
    Proposed resolution:
    
-
      
-
    1. 
-
      
-In 30.6.6 [futures.promise], before p.1, immediately after class template
-promise add:
-
      
-
      
-template <class R>
-void swap(promise<R>& x, promise<R>& y);
-
-
      
-
      2. 
-
    2. 
+
      
 
      
-Change 30.6.6 [futures.promise]/10 as indicated (to fix a circular definition):
+We note there is a pending paper by Detlef
+on such future-related issues;
+we would like to wait for his paper before proceeding.
 
      
-
      
 
      
--10- Effects: swap(*this, other)Swaps the associated state
-of *this and other
+Alisdair suggests we may want language to clarify that this
+get() function can be called from several threads
+with no need for explicit locking.
 
      
 
      
-Throws: Nothing.
+Move to Open.
 
      
 
      
-
      3. 
-
    3. 
+
+
+
      Proposed resolution:
      
 
      
-After the last paragraph in 30.6.6 [futures.promise] add the following
-prototype description:
+Change 30.6.6 [future.shared_future]:
 
      
-
      
-template <class R>
-void swap(promise<R>& x, promise<R>& y);
-
      
+
+
      const R& shared_future::get() const; 
+R& shared_future<R&>::get() const; 
+void shared_future<void>::get() const;
+
      
 
      
+
      ...
      
 
      
-Effects: x.swap(y)
-
      
-
      
-Throws: Nothing.
+-9- Throws: the stored exception, if an exception was stored and not retrieved before.
+
+[Note: Multiple calls on get() are 
+allowed, and each call would result in an exception if an exception was 
+stored. — end note]
+
 
      
 
      
 
      
-
      4. 
-
-
    
 
 
 
@@ -33185,385 +27146,408 @@ void swap(promise<R>& x, promise<R>& y);
 
 
 
    
-
    1089. Response to JP 76
    
-
    Section: 30 [thread] Status: Open
- Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-03-22
    
-
    View other active issues in [thread].
    
-
    View all other issues in [thread].
    
+
    1108. thread.req.exception overly constrains implementations
    
+
    Section: 30.2.2 [thread.req.exception] Status: Open
+ Submitter: Christopher Kohlhoff Opened: 2009-04-25  Last modified: 2009-05-23
    
 
    View all issues with Open status.
    
-
    Discussion:
    
-
    Addresses JP 76
    
-
-
    
-A description for "Throws: Nothing." are not unified.
-
    
-
+
    Discussion:
    
 
    
-At the part without throw, "Throws: Nothing." should be described.
+The current formulation of 30.2.2 [thread.req.exception]/2 reads:
 
    
-
+
    
+The error_category of the error_code reported by such an
+exception's code() member function is as specified in the error
+condition Clause.
+
    
 
    
-Add "Throws: Nothing." to the following.
+This constraint on the code's associated error_categor means an
+implementation must perform a mapping from the system-generated
+error to a generic_category() error code. The problems with this
+include:
 
    
 
 
      
 
    • 
-30.3.1.6 [thread.thread.static] p1
-
      • 
-
    • 
-30.4.3.1 [thread.lock.guard] p4
+The mapping is always performed, even if the resultant value is
+ never used.
 
      • 
 
    • 
-30.4.3.2.1 [thread.lock.unique.cons] p6
+
      
+The original error produced by the operating system is lost.
+
      
 
      • 
+
    
+
    
+The latter was one of Peter Dimov's main objections (in a private
+email discussion) to the original error_code-only design, and led to
+the creation of error_condition in the first place. Specifically,
+error_code and error_condition are intended to perform the following
+roles:
+
    
+
      
 
    • 
-30.5.1 [thread.condition.condvar] p7 and p8
+error_code holds the original error produced by the operating
+ system.
 
      • 
 
    • 
-30.5.2 [thread.condition.condvarany] p6, p7, p19, p21 and p25
+error_condition and the generic category provide a set of well
+ known error constants that error codes may be tested against.
 
      • 
 
    
+
    
+Any mapping determining correspondence of the returned error code to
+the conditions listed in the error condition clause falls under the
+"latitude" granted to implementors in 19.5.1.5 [syserr.errcat.objects].
+(Although obviously their latitude is restricted a little by the
+need to match the right error condition when returning an error code
+from a library function.)
+
    
+
    
+It is important that this error_code/error_condition usage is done
+correctly for the thread library since it is likely to set the
+pattern for future TR libraries that interact with the operating
+system.
+
    
 
 
    [
-Summit:
+Batavia (2009-05):
 ]
    
 
 
    
-Pass on to editor.
+Move to Open, and recommend the issue be deferred until after the next
+Committee Draft is issued.
 
    
 
-
    [
-Post Summit:  Editor declares this non-editorial.
-]
    
 
+
    Proposed resolution:
    
+
    
+Change 30.2.2 [thread.req.exception]/2:
+
    
+
+
    
+
    
+-2- The error_category (19.5.1.1) of the error_code reported by
+such an exception's code() member function 
+is as specified in the error condition Clause.
+
+The error_code reported by such an exception's code() member
+function shall compare equal to one of the conditions specified in
+the function's error condition Clause. [Example: When the thread
+constructor fails:
+
+
    
+
    
+ec.category() == implementation-defined // probably system_category
+ec == errc::resource_unavailable_try_again // holds true
+
    
+
+
    
+— end example]
+
    
 
+
    
 
-
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1090. Missing description of packaged_task member swap,  missing non-member swap
    
-
    Section: 30.6.8 [futures.task] Status: Open
- Submitter: Daniel Krügler Opened: 2009-03-22  Last modified: 2009-05-24
    
+
    1110. Is for_each overconstrained?
    
+
    Section: 25.3.4 [alg.foreach] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-04-29  Last modified: 2009-05-23
    
+
    View all other issues in [alg.foreach].
    
 
    View all issues with Open status.
    
 
    Discussion:
    
 
    
-Class template packaged_task in 30.6.8 [futures.task] shows a member swap
-declaration, but misses to
-document it's effects (No prototype provided). Further on this class
-misses to provide a non-member
-swap.
+Quoting working paper for reference (25.3.4 [alg.foreach]):
 
    
 
-
    [
-Batavia (2009-05):
-]
    
-
+
    
+
    template<InputIterator Iter, Callable<auto, Iter::reference> Function>
+  requires CopyConstructible<Function>
+  Function for_each(Iter first, Iter last, Function f);
+
    
 
    
 
    
-Alisdair notes that paragraph 2 of the proposed resolution has already been
-applied in the current Working Draft.
+1 Effects: Applies f to the result of dereferencing every iterator in the
+ range [first,last), starting from first and proceeding to last - 1.
 
    
 
    
-We note a pending future-related paper by Detlef;
-we would like to wait for this paper before proceeding.
+2 Returns: f.
 
    
 
    
-Move to Open.
+3 Complexity: Applies f exactly last - first times.
 
    
 
    
+
    
+
+
    
+P2 implies the passed object f should be invoked at each stage, rather than
+some copy of f.  This is important if the return value is to usefully
+accumulate changes.  So the requirements are an object of type Function can
+be passed-by-value, invoked multiple times, and then return by value.  In
+this case, MoveConstructible is sufficient. This would open support for
+move-only functors, which might become important in concurrent code as you
+can assume there are no other references (copies) of a move-only type and so
+freely use them concurrently without additional locks.
+
    
 
 
    [
-2009-05-24 Daniel removed part 2 of the proposed resolution.
+See further discussion starting with c++std-lib-23686.
 ]
    
 
 
+
    [
+Batavia (2009-05):
+]
    
 
-
    Proposed resolution:
    
-
      
-
    1. 
+
      
 
      
-In 30.6.8 [futures.task], immediately after the definition of class
-template packaged_task add:
+Pete suggests we may want to look at this in a broader context
+involving other algorithms.
+We should also consider the implications of parallelism.
 
      
-
      
-template<class R, class... Argtypes>
-void swap(packaged_task<R(ArgTypes...)>&, packaged_task<R(ArgTypes...)>&);
-
-
      
-
      2. 
-
    
-
-
      
-
    1. 
 
      
-In 30.6.8 [futures.task], immediately after operator= prototype
-description (After p. 8) add:
+Move to Open, and recommend the issue be deferred until after the next
+Committee Draft is issued.
 
      
-
      void swap(packaged_task& other);
-
      
-
      
-
      
-Effects: Swaps the associated state of *this and other.
-
      
-
      
-Throws: Nothing.
-
      
 
      
-
      
-
      2. 
-
    2. 
+
+
+
      Proposed resolution:
      
 
      
-At the end of 30.6.8 [futures.task] (after p. 20), add add the following
-prototype description:
+Change 25.2 [algorithms.syn] and 25.3.4 [alg.foreach]:
 
      
 
-
      
-template<class R, class... Argtypes>
-void swap(packaged_task<R(ArgTypes...)>& x, packaged_task<R(ArgTypes...)>& y);
-
      
-
      
-
      
-Effects: x.swap(y)
-
      
-
      
-Throws: Nothing.
-
      
-
      
-
      
-
      3. 
-
    
+
    template<InputIterator Iter, Callable<auto, Iter::reference> Function>
+  requires CopyConstructible MoveConstructible<Function>
+  Function for_each(Iter first, Iter last, Function f);
+
    
 
 
 
 
 
 
    
-
    1091. Response to UK 246
    
-
    Section: 23.4.2.2 [multimap.modifiers] Status: Review
- Submitter: Beman Dawes Opened: 2009-03-22  Last modified: 2009-05-23
    
-
    View all issues with Review status.
    
+
    1112. bitsets and new style for loop
    
+
    Section: 20.3.6 [template.bitset] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-05-06  Last modified: 2009-07-25
    
+
    View other active issues in [template.bitset].
    
+
    View all other issues in [template.bitset].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
-
-
    Addresses UK 246
    
 
    
-The content of this sub-clause is purely trying to describe in words the
-effect of the requires clauses on these operations, now that we have
-Concepts. As such, the description is more confusing than the signature
-itself. The semantic for these functions is adequately covered in the
-requirements tables in 23.2.4 [associative.reqmts].
+Std::bitset is a homogeneous container-like sequence of bits, yet it does
+not model the Range concept so cannot be used with the new for-loop syntax.
+It is the only such type in the library that does NOT support the new for
+loop.
+
    
+
    
+The obvious reason is that bitset does not support iterators.
+
    
+
    
+At least two reasonable solutions are available:
+
    
+
      
+
    1. 
+Add an iterator interface to bitset, bringing its interface close to that
+of std::array
+
      2. 
+
    2. 
+Provide an unspecified concept_map for Range<bitset>.
+
      3. 
+
    
+
    
+The latter will still need some kind of iterator-like adapter for bitset,
+but gives implementers greater freedom on the details. E.g. begin/end return
+some type that simply invokes operator[] on the object it wraps, and
+increments its index on operator++.  A vendor can settle for InputIterator
+support, rather than wrapping up a full RandomAccessIterator.
+
    
+
    
+I have a mild preference for option (ii) as I think it is less work to
+specify at this stage of the process, although (i) is probably more useful
+in the long run.
+
    
+
    
+Hmm, my wording looks a little woolly, as it does not say what the element
+type of the range is.  Do I get a range of bool, bitset<N>::reference, or
+something else entirely?
+
    
+
    
+I guess most users will assume the behaviour of reference, but expect to
+work with bool.  Bool is OK for read-only traversal, but you really need to
+take a reference to a bitset::reference if you want to write back.
 
    
-
-
    [
-Beman adds:
-]
    
-
-
-
    
-Pete is clearly right that
-this one is technical rather than editorial.
-
    
 
 
    [
 Batavia (2009-05):
 ]
    
 
 
    
-
    
-We agree with the proposed resolution.
-
    
-
    
-Move to Review.
-
    
+Move to Open.
+We further recommend this be deferred until after the next Committee Draft.
 
    
 
+
    [
+2009-05-25 Alisdair adds:
+]
    
 
-
    Proposed resolution:
    
+
+
    
 
    
-Strike 23.4.2.2 [multimap.modifiers] entirely
-(but do NOT strike these signatures from the class template definition!).
+I just stumbled over the Range concept_map for valarray and this should
+probably set the precedent on how to write the wording.
 
    
 
+
    [
+Howard: I've replaced the proposed wording with Alisdair's suggestion.
+]
    
 
 
-
-
-
    
-
    1092. Class template integral_constant should be a  constrained template
    
-
    Section: 20.6.3 [meta.help] Status: Open
- Submitter: Daniel Krügler Opened: 2009-03-22  Last modified: 2009-05-23
    
-
    View other active issues in [meta.help].
    
-
    View all other issues in [meta.help].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    
-A first step to change the type traits predicates to constrained templates is to
-constrain their common base template integral_constant. This can be done,
-without enforcing depending classes to be constrained as well, but not
-vice versa
-without brute force late_check usages. The following proposed resolution depends
-on the resolution of LWG issue 1019.
-
    
+
    
 
 
    [
-Batavia (2009-05):
+2009-07-24 Daniel modifies the proposed wording for non-concepts.
 ]
    
 
-
    
-Move to Open, pending a paper that looks at constraints
-for the entirety of the type traits
-and their relationship to the foundation concepts.
-We recommend this be deferred
-until after the next Committee Draft is issued.
-
    
+
 
 
 
    Proposed resolution:
    
 
      
 
    1. 
 
      
-In 20.6.2 [meta.type.synop], Header <type_traits>
-synopsis change as indicated:
+Modify the section 20.3.6 [template.bitset] <bitset> synopsis by adding
+the following at the end of the synopsis:
 
      
-
      namespace std {
-// 20.5.3, helper class:
-template <classIntegralConstantExpressionType T, T v> struct integral_constant;
+
      
+// XX.X.X bitset range access [bitset.range]
+template<size_t N> unspecified-1 begin(bitset<N>&);
+template<size_t N> unspecified-2 begin(const bitset<N>&);
+template<size_t N> unspecified-1 end(bitset<N>&);
+template<size_t N> unspecified-2 end(const bitset<N>&);
+
 
      
 
      2. 
 
    2. 
 
      
-In 20.6.3 [meta.help] change as indicated:
+Add a new section "bitset range access" [bitset.range]
+after the current section 20.3.6.3 [bitset.operators] with the following series of
+paragraphs:
 
      
-
      template <classIntegralConstantExpressionType T, T v>
-struct integral_constant {
-  static constexpr T value = v;
-  typedef T value_type;
-  typedef integral_constant<T,v> type;
-  constexpr operator value_type() { return value; }
-};
-
      
-
      3. 
-
    
+
    
+
    
+
+1.  In the begin and end function templates that follow, unspecified-1
+is a type that meets the requirements of a mutable random access
+iterator (24.2.6 [random.access.iterators]) whose value_type is bool and
+whose reference type is bitset<N>::reference.
+unspecified-2 is a type that meets the requirements of a constant
+random access iterator (24.2.6 [random.access.iterators]) whose value_type
+is bool and whose reference type is bool.
+
+
    
+
    
+template<size_t N> unspecified-1 begin(bitset<N>&);
+template<size_t N> unspecified-2 begin(const bitset<N>&);
+
+
    
+
    
+2.  Returns: an iterator referencing the first bit in the bitset.
+
    
 
+
    
+template<size_t N> unspecified-1 end(bitset<N>&);
+template<size_t N> unspecified-2 end(const bitset<N>&);
+
    
 
+
    
+3.  Returns: an iterator referencing one past the last bit in the
+bitset.
+
    
+
    
+
+
 
 
 
-
    
-
    1093. Multiple definitions for random_shuffle algorithm
    
-
    Section: 25.4.12 [alg.random.shuffle] Status: Review
- Submitter: Alisdair Meredith Opened: 2009-03-22  Last modified: 2009-06-09
    
-
    View all other issues in [alg.random.shuffle].
    
-
    View all issues with Review status.
    
-
    Discussion:
    
 
-
    
-There are a couple of issues with the declaration of the random_shuffle
-algorithm accepting a random number engine.
-
    
 
-
      
-
    1. 
-The Iterators must be shuffle iterators, yet this requirement is missing.
-
      2. 
-
    2. 
-The RandomNumberEngine concept is now provided by the random number
-library
-(n2836)
-and the placeholder should be removed.
-
      3. 
-
    
 
-
    [
-2009-05-02 Daniel adds:
-]
    
 
 
-
    
-
    
-this issue completes adding necessary requirement to the
-third new random_shuffle overload. The current suggestion is:
-
    
 
-
    template<RandomAccessIterator Iter, UniformRandomNumberGenerator Rand>
-requires ShuffleIterator<Iter>
-void random_shuffle(Iter first, Iter last, Rand&& g);
-
    
 
-
    
-IMO this is still insufficient and I suggest to add the requirement
-
    
-
    Convertible<Rand::result_type, Iter::difference_type>
-
    
-
    
-to the list (as the two other overloads already have).
-
    
 
-
    
-Rationale:
-
    
 
-
    
-
    
-Its true that this third overload is somewhat different from the remaining
-two. Nevertheless we know from UniformRandomNumberGenerator, that
-it's result_type is an integral type and that it satisfies
-UnsignedIntegralLike<result_type>.
-
    
+
    
+
    1113. bitset::to_string could be simplified
    
+
    Section: 20.3.6 [template.bitset] Status: Open
+ Submitter: Alisdair Meredith Opened: 2009-05-09  Last modified: 2009-05-23
    
+
    View other active issues in [template.bitset].
    
+
    View all other issues in [template.bitset].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
 
    
-To realize it's designated task, the algorithm has to invoke the
-Callable aspect of g and needs to perform some algebra involving
-it's min()/max() limits to compute another index value that
-at this point is converted into Iter::difference_type. This is so,
-because 24.2.6 [random.access.iterators] uses this type as argument
-of it's algebraic operators. Alternatively consider the equivalent
-iterator algorithms in 24.4 [iterator.operations] with the same result.
+In 853 our resolution is changing the signature by adding two
+defaulting arguments to 3 calls.  In principle, this means that ABI breakage
+is not an issue, while API is preserved.
 
    
 
    
-This argument leads us to the conclusion that we also need
-Convertible<Rand::result_type, Iter::difference_type> here.
+With that observation, it would be very nice to use the new ability to
+supply default template parameters to function templates to collapse all 3
+signatures into 1.  In that spirit, this issue offers an alternative resolution
+than that of 853.
 
    
-
    
-
-
    
 
 
    [
 Batavia (2009-05):
 ]
    
 
 
    
-
    
-Alisdair notes that point (ii) has already been addressed.
-
    
-
    
-We agree with the proposed resolution to point (i)
-with Daniel's added requirement.
-
    
-
    
-Move to Review.
-
    
+Move to Open,
+and look at the issue again after 853 has been accepted.
+We further recommend this be deferred until after the next Committee Draft.
 
    
 
-
    [
-2009-06-05 Daniel updated proposed wording as recommended in Batavia.
-]
    
-
-
 
 
    Proposed resolution:
    
+
+
      
+
    1. 
 
      
-Change in 25.2 [algorithms.syn] and 25.4.12 [alg.random.shuffle]:
+In 20.3.6 [template.bitset]/1 (class bitset) ammend:
 
      
-
-
      concept UniformRandomNumberGenerator<typename Rand> { }
-template<RandomAccessIterator Iter, UniformRandomNumberGenerator Rand>
-  requires ShuffleIterator<Iter> &&
-  Convertible<Rand::result_type, Iter::difference_type>
-  void random_shuffle(Iter first, Iter last, Rand&& g);
+
      template <class charT = char,
+            class traits = char_traits<charT>,
+            class Allocator = allocator<charT>> 
+  basic_string<charT, traits, Allocator>
+  to_string(charT zero = charT('0'), charT one = charT('1')) const;
+template <class charT, class traits> 
+  basic_string<charT, traits, allocator<charT> > to_string() const; 
+template <class charT> 
+  basic_string<charT, char_traits<charT>, allocator<charT> > to_string() const; 
+basic_string<char, char_traits<char>, allocator<char> > to_string() const;
+
      
+
      2. 
+
    2. 
+
      
+In 20.3.6.2 [bitset.members] prior to p35 ammend:
+
      
+
      template <class charT = char,
+            class traits = char_traits<charT>,
+            class Allocator = allocator<charT>> 
+  basic_string<charT, traits, Allocator>
+  to_string(charT zero = charT('0'), charT one = charT('1')) const;
 
      
+
      3. 
+
    3. 
+Strike 20.3.6.2 [bitset.members] paragraphs 37 -> 39 (including signature
+above 37)
+
      4. 
+
    
 
 
 
@@ -33571,168 +27555,152 @@ template<RandomAccessIterator Iter, UniformRandomNumberGenerator Rand>
 
 
 
    
-
    1094. Response to JP 65 and JP 66
    
-
    Section: 27.5.4.3 [iostate.flags] Status: Review
- Submitter: P.J. Plauger Opened: 2009-03-24  Last modified: 2009-05-23
    
-
    View all other issues in [iostate.flags].
    
-
    View all issues with Review status.
    
+
    1114. Type traits underspecified
    
+
    Section: 20.6 [meta] Status: Open
+ Submitter: Daniel Krügler Opened: 2009-05-12  Last modified: 2009-05-23
    
+
    View other active issues in [meta].
    
+
    View all other issues in [meta].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
-
    Addresses JP 65 and JP 66
    
 
 
    
-Switch from "unspecified-bool-type" to "explicit operator bool() const". 
+Related to 975 and 1023.
 
    
 
 
    
-Replace operator unspecified-bool-type() const;" with explicit operator bool() const;
+The current wording in 20.6.1 [meta.rqmts] is still unclear concerning
+it's requirements on the type traits classes regarding ambiguities.
+Specifically it's unclear
 
    
 
+
      
+
    • 
+if a predicate trait (20.6.4 [meta.unary], 20.6.5 [meta.rel]) could derive from both
+true_type/false_type.
+
      • 
+
    • 
+if any of the type traits (20.6.1 [meta.rqmts], 20.6.4 [meta.unary], 20.6.5 [meta.rel]) could ambiguously derive
+from the same specified result type.
+
      • 
+
    • 
+if any of the type traits (20.6.1 [meta.rqmts], 20.6.4 [meta.unary], 20.6.5 [meta.rel]) could derive from other
+integral_constant types making the contained names ambiguous
+
      • 
+
    • 
+if any of the type traits (20.6.1 [meta.rqmts], 20.6.4 [meta.unary], 20.6.5 [meta.rel]) could have other base
+classes that contain members hiding the name of the result type members
+or make the contained member names ambiguous.
+
      • 
+
    
+
 
    [
 Batavia (2009-05):
 ]
    
 
 
    
-We agree with the proposed resolution.
-Move to Review.
-
    
-
-
-
    Proposed resolution:
    
-
    
-Change the synopis in 27.5.4 [ios]:
-
    
-
-
    explicit operator unspecified-bool-type bool() const;
-
    
-
-
    
-Change 27.5.4.3 [iostate.flags]:
-
    
-
-
    explicit operator unspecified-bool-type bool() const;
-
    
-
-
    
 
    
--1- Returns: !fail() If fail() then a value that will evaluate
-false in a boolean context; otherwise a value that will evaluate true in
-a boolean context. The value type returned shall not be convertible to
-int.
+Alisdair would prefer to factor some of the repeated text,
+but modulo a corner case or two,
+he believes the proposed wording is otherwise substantially correct.
 
    
 
    
-[Note: This conversion can be used in contexts where a bool is expected
-(e.g., an if condition); however, implicit conversions (e.g.,
-to int) that can occur with bool are not allowed,
-eliminating some sources of user error. One possible implementation
-choice for this type is pointer-to-member. -- end note]
+Move to Open.
 
    
 
    
-
    
-
-
-
 
 
+
    Proposed resolution:
    
+
    [
+The usage of the notion of a BaseCharacteristic below
+might be
+useful in other places - e.g. to define the base class relation in
+20.7.5 [refwrap], 20.7.15 [func.memfn], or 20.7.16.2 [func.wrap.func].
+In this case it's definition should probably
+be moved to Clause 17
+]
    
 
 
-
    
-
    1095. Shared objects and the library wording unclear
    
-
    Section: 17.6.3.10 [res.on.objects] Status: Review
- Submitter: Beman Dawes Opened: 2009-03-27  Last modified: 2009-05-23
    
-
    View all issues with Review status.
    
-
    Discussion:
    
+
      
+
    1. 
 
      
-N2775,
-Small library thread-safety revisions, among other changes, removed a note from
-17.6.3.10 [res.on.objects] that read:
+Change 20.6.1 [meta.rqmts]/1 as indicated:
 
      
-
 
      
-[Note: This prohibition against concurrent non-const access means that
-modifying an object of a standard library type shared between threads
-without using a locking mechanism may result in a data race. --end note.]
+[..] It shall be DefaultConstructible, CopyConstructible, and publicly
+and unambiguously derived, directly or indirectly, from
+its BaseCharacteristic, which is a specialization of the
+template integral_constant (20.6.3), with the arguments to the template
+integral_constant determined by the requirements for the particular
+property being described. The member names of the
+BaseCharacteristic shall be unhidden and unambiguously
+available in the UnaryTypeTrait.
 
      
-
+
      2. 
+
    2. 
 
      
-That resulted in wording which is technically correct but can only be
-understood by reading the lengthy and complex 17.6.4.7 [res.on.data.races]
-Data race avoidance. This has the effect of making
-17.6.3.10 [res.on.objects] unclear, and has already resulted in a query
-to the LWG reflector. See c++std-lib-23194.
+Change 20.6.1 [meta.rqmts]/2 as indicated:
 
      
-
-
      [
-Batavia (2009-05):
-]
      
-
 
      
+[..] It shall be DefaultConstructible, CopyConstructible, and publicly
+and unambiguously derived, directly or indirectly, from
+an instance its BaseCharacteristic, which is a
+specialization of the template integral_constant (20.6.3), with
+the arguments to the template integral_constant determined by the
+requirements for the particular relationship being described. The
+member names of the BaseCharacteristic shall be unhidden
+and unambiguously available in the BinaryTypeTrait.
+
      
+
      3. 
+
    3. 
 
      
-The proposed wording seems to need a bit of tweaking
-("really bad idea" isn't quite up to standardese).
-We would like feedback
-as to whether the original Note's removal was intentional.
-
      
-
      
-Change the phrase "is a really bad idea"
-to "risks undefined behavior" and
-move to Review status.
+Change 20.6.4 [meta.unary]/2 as indicated:
 
      
+
      
+Each of these templates shall be a UnaryTypeTrait (20.6.1),
+publicly derived directly or indirectly from true_type if the
+corresponding condition is true, otherwise from false_type
+where its BaseCharacteristic shall be true_type if the
+corresponding condition is true, otherwise false_type.
 
      
-
-
-
      Proposed resolution:
      
+
      4. 
+
    4. 
 
      
-Change 17.6.3.10 [res.on.objects] as indicated:
+Change 20.6.5 [meta.rel]/2 as indicated:
 
      
 
 
      
-
      
-The behavior of a program is undefined if calls to standard library
-functions from different threads may introduce a data race. The
-conditions under which this may occur are specified in 17.6.4.7.
-
      
-
      
-[Note: Thus modifying an object of a standard library type shared between
-threads risks undefined behavior unless objects of the type are explicitly
-specified as being sharable without data races or the user supplies a
-locking mechanism. --end note]
-
      
+Each of these templates shall be a BinaryTypeTrait (20.6.1),
+publicly derived directly or indirectly from true_type if the
+corresponding condition is true, otherwise from false_type
+where its BaseCharacteristic shall be true_type if the
+corresponding condition is true, otherwise false_type.
 
      
+
      5. 
+
    
+
 
 
 
 
 
 
    
-
    1096. unconstrained rvalue ref parameters
    
-
    Section: 17 [library] Status: Open
- Submitter: David Abrahams Opened: 2009-03-21  Last modified: 2009-05-23
    
-
    View other active issues in [library].
    
-
    View all other issues in [library].
    
-
    View all issues with Open status.
    
+
    1115. va_copy missing from Standard macros table
    
+
    Section: C.2 [diff.library] Status: New
+ Submitter: Miles Zhao Opened: 2009-05-23  Last modified: 2009-05-23
    
+
    View other active issues in [diff.library].
    
+
    View all other issues in [diff.library].
    
+
    View all issues with New status.
    
 
    Discussion:
    
 
    
-TODO: Look at all cases of unconstrained rvalue ref parameters and check
-that concept req'ts work when T deduced as reference.
-
    
-
-
    
- We found some instances where that was not done correctly and we figure
-   the possibility of deducing T to be an lvalue reference was probably
-   overlooked elsewhere.
+In "Table 122 -- Standard macros" of C.2 [diff.library], which lists the 56 macros
+inherited from C library, va_copy seems to be missing. But in
+"Table 21 -- Header <cstdarg> synopsis" (18.10 [support.runtime]), there is.
 
    
 
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-Move to Open, pending proposed wording from Dave for further review.
-
    
-
 
 
    Proposed resolution:
    
 
    
+Add va_copy to Table 122 -- Standard macros in C.2 [diff.library].
 
    
 
 
@@ -33740,421 +27708,581 @@ Move to Open, pending proposed wording from Dave for further review.
 
 
 
    
-
    1097. #define __STDCPP_THREADS
    
-
    Section: 18.2 [support.types] Status: Review
- Submitter: Jens Maurer Opened: 2009-04-03  Last modified: 2009-05-23
    
-
    View all other issues in [support.types].
    
-
    View all issues with Review status.
    
+
    1116. Literal constructors for tuple
    
+
    Section: 20.5.2 [tuple.tuple] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-05-23  Last modified: 2009-05-24
    
+
    View all other issues in [tuple.tuple].
    
+
    View all issues with New status.
    
 
    Discussion:
    
-
    Addresses DE 18
    
-
 
    
-Freestanding implementations do not (necessarily) have
-  support for multiple threads (see 1.10 [intro.multithread]).
-  Applications and libraries may want to optimize for the
-  absence of threads.  I therefore propose a preprocessor
-  macro to indicate whether multiple threads can occur.
+It is not currently possible to construct tuple literal values,
+even if the elements are all literal types.  This is because parameters
+are passed to constructor by reference.
 
    
-
 
    
-There is ample prior implementation experience for this
-  feature with various spellings of the macro name.  For
-  example, gcc implicitly defines _REENTRANT
-  if multi-threading support is selected on the compiler
-  command-line.
+An alternative would be to pass all constructor arguments by value, where it
+is known that *all* elements are literal types.  This can be determined with
+concepts, although note that the negative constraint really requires
+factoring out a separate concept, as there is no way to provide an 'any of
+these fails' constraint inline.
 
    
-
 
    
-While this is submitted as a library issue, it may be more
-  appropriate to add the macro in 16.8 cpp.predefined in the
-  core language.
+Note that we will have similar issues with pair (and
+tuple constructors from pair) although I am steering
+clear of that class while other constructor-related issues settle.
 
    
 
+
+
    Proposed resolution:
    
 
    
-See also
-N2693.
+Ammend the tuple class template declaration in 20.5.2 [tuple.tuple] as
+follows
 
    
 
-
    [
-Batavia (2009-05):
-]
    
-
 
    
 
    
-We agree with the issue, and believe it is properly a library issue.
-
    
-
    
-We prefer that the macro be conditionally defined
-as part of the <thread> header.
-
    
-
    
-Move to Review.
+Add the following concept:
 
    
-
    
 
+
    auto concept AllLiteral< typename ... Types > {
+  requires LiteralType<Types>...;
+}
+
    
 
-
    Proposed resolution:
    
 
    
-Insert a new subsection before 18.2 [support.types], entitled
-"Feature Macros" (support.macros):
+ammend the constructor 
 
    
-
    
+
+
    template <class... UTypes>
+  requires AllLiteral<Types...>
+        && Constructible<Types, UTypes>...
+  explicit tuple(UTypes...);
+
+template <class... UTypes>
+  requires !AllLiteral<Types...>
+        && Constructible<Types, UTypes&&>...
+  explicit tuple(UTypes&&...);
+
    
+
 
    
-The standard library defines the following macros; no explicit
-prior inclusion of any header file is necessary.
+ammend the constructor
 
    
-
    
-
    
-
    __STDCPP_THREADS
    
-
    
-The macro __STDCPP_THREADS shall be defined if and only if a
-    program can have more than one thread of execution (1.10 [intro.multithread]).
-If the macro is defined, it shall have the same
-    value as the predefined macro __cplusplus (16.8 [cpp.predefined]).
-
    
-
    
-
    
+
+
    template <class... UTypes>
+  requires AllLiteral<Types...>
+        && Constructible<Types, UTypes>...
+  tuple(tuple<UTypes...>);
+
+template <class... UTypes>
+  requires !AllLiteral<Types...>
+        && Constructible<Types, const UTypes&>...
+  tuple(const tuple<UTypes...>&);
+
    
+
 
    
 
+
    
+Update the same signatures in 20.5.2.1 [tuple.cnstr], paras 3 and 5.
+
    
 
 
 
 
 
 
    
-
    1098. definition of get_pointer_safety()
    
-
    Section: 20.8.13.7 [util.dynamic.safety] Status: Open
- Submitter: Jens Maurer Opened: 2009-04-03  Last modified: 2009-05-23
    
-
    View all other issues in [util.dynamic.safety].
    
-
    View all issues with Open status.
    
-
    Discussion:
    
-
    Addresses DE 18
    
-
+
    1117. tuple copy constructor
    
+
    Section: 20.5.2.1 [tuple.cnstr] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-05-23  Last modified: 2009-05-30
    
+
    View other active issues in [tuple.cnstr].
    
+
    View all other issues in [tuple.cnstr].
    
+
    View all issues with New status.
    
+
    Discussion:
    
 
    
- In 20.8.13.7 [util.dynamic.safety], get_pointer_safety() purports
-to define behavior for
- non-safely derived pointers (3.7.4.3 [basic.stc.dynamic.safety]).  However,
- the cited core-language section in paragraph 4 specifies undefined behavior
- for the use of such pointer values.  This seems an unfortunate near-contradiction.
- I suggest to specify the term relaxed pointer safety in
- the core language section and refer to it from the library description.
- This issue deals with the library part, the corresponding core issue (c++std-core-13940)
- deals with the core modifications.
+The copy constructor for the tuple template is constrained.  This seems an
+unusual strategy, as the copy constructor will be implicitly deleted if the
+constraints are not met.  This is exactly the same effect as requesting an
+=default; constructor.  The advantage of the latter is that it retains
+triviality, and provides support for tuples as literal types if issue
+1116 is also accepted.
 
    
-
 
    
-See also
-N2693.
+Actually, it might be worth checking with core if a constrained copy
+constructor is treated as a constructor template, and as such does not
+suppress the implicit generation of the copy constructor which would hide
+the template in this case.
 
    
 
 
    [
-Batavia (2009-05):
+2009-05-27 Daniel adds:
 ]
    
 
+
 
    
-
    
-We recommend if this issue is to be moved,
-the issue be moved concurrently with the cited Core issue.
-
    
-
    
-We agree with the intent of the proposed resolution.
-We would like input from garbage collection specialists.
-
    
-
    
-Move to Open.
-
    
+This would solve one half of the suggested changes in 801.
 
    
 
 
-
 
    Proposed resolution:
    
 
    
-In 20.8.13.7 [util.dynamic.safety] p16, replace the description of
-get_pointer_safety() with:
-
    
-
-
    
-
    
-pointer_safety get_pointer_safety();
-
    
-
    
-
    
-Returns: an enumeration value indicating the implementation's treatment
-of pointers that are not safely derived (3.7.4.3). Returns
-pointer_safety::relaxed if pointers that are not safely derived will be
-treated the same as pointers that are safely derived for the duration of
-the program. Returns pointer_safety::preferred if pointers that are not
-safely derived will be treated the same as pointers that are safely
-derived for the duration of the program but allows the implementation to
-hint that it could be desirable to avoid dereferencing pointers that are
-not safely derived as described. [Example: pointer_safety::preferred
-might be returned to detect if a leak detector is running to avoid
-spurious leak reports. -- end note] Returns pointer_safety::strict if
-pointers that are not safely derived might be treated differently than
-pointers that are safely derived.
-
    
-
    
-Returns: Returns pointer_safety::strict if the implementation has
-   strict pointer safety (3.7.4.3 [basic.stc.dynamic.safety]). It is
-   implementation-defined whether get_pointer_safety returns
-   pointer_safety::relaxed or pointer_safety::preferred if the
-   implementation has relaxed pointer safety
-   (3.7.4.3 [basic.stc.dynamic.safety]).Footnote
-
    
-
-
    
-Throws: nothing
-
    
-
-
    
-Footnote) pointer_safety::preferred might be returned to indicate to the
-   program that a leak detector is running so that the program can avoid
-   spurious leak reports.
-
+Change 20.5.2 [tuple.tuple] and 20.5.2.1 [tuple.cnstr] p4:
 
    
 
-
    
-
    
+
    requires CopyConstructible<Types>... tuple(const tuple&) = default;
+
    
 
 
 
 
 
 
    
-
    1099. Various issues
    
-
    Section: 17 [library] Status: Open
- Submitter: David Abrahams Opened: 2009-03-21  Last modified: 2009-05-23
    
-
    View other active issues in [library].
    
-
    View all other issues in [library].
    
-
    View all issues with Open status.
    
+
    1118. tuple query APIs do not support cv-qualification
    
+
    Section: 20.5.2.3 [tuple.helper] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-05-23  Last modified: 2009-05-25
    
+
    View other active issues in [tuple.helper].
    
+
    View all other issues in [tuple.helper].
    
+
    View all issues with New status.
    
 
    Discussion:
    
 
    
-Notes
+The APIs tuple_size and tuple_element do not support
+cv-qualified tuples, pairs or arrays.
 
    
-
    
 
    
-[2009-03-21 Sat] p. 535 at the top we need MoveConstructible V1,
-MoveConstructible V2 (where V1,V2 are defined on 539).  Also make_tuple
-on 550
+The most generic solution would be to supply partial specializations once
+for each cv-type in the tuple header.  However, requiring this header for
+cv-qualified pairs/arrays seems unhelpful.  The BSI editorial
+suggestion (UK-198/US-69,
+N2533)
+to merge tuple into <utility> would help with pair,
+but not array.  That might be resolved by making a dependency between the
+<array> header and <utility>, or simply recognising
+the dependency be fulfilled in a Remark.
 
    
+
+
    [
+2009-05-24 Daniel adds:
+]
    
+
+
+
    
 
    
-[2009-03-21 Sat] p1183 thread ctor, and in general, we need a way to
-talk about "copiable from generalized rvalue ref argument" for cases
-where we're going to forward and copy.  
+All tuple_size templates with a base class need to derive publicly, e.g.
 
    
-
    
+
+
    template <IdentityOf T> class tuple_size< const T > :
+   public tuple_size<T> {};
+
    
+
 
    
-   This issue may well be quite large.  Language in para 4 about "if
-   an lvalue" is wrong because types aren't expressions.
+The same applies to the tuple_element class hierarchies.
 
    
 
    
-   p1199, call_once has all the same issues.
+What is actually meant with the comment
 
    
+
    
+this solution relies on 'metafunction forwarding' to inherit the
+nested typename type
 
    
 
    
-[2009-03-21 Sat] p869 InputIterator pointer type should not be required
-to be convertible to const value_type*, rather it needs to have a
-operator-> of its own that can be used for the value type.
+?
 
    
 
    
-[2009-03-21 Sat] p818 stack has the same problem with default ctor.
+I ask, because all base classes are currently unconstrained and their
+instantiation is invalid in the constrained context of the tuple_element partial
+template specializations.
 
    
+
    
+
+
    [
+2009-05-24 Alisdair adds:
+]
    
+
+
+
    
 
    
-[2009-03-21 Sat] p816 priority_queue has the same sorts of problems as queue, only more so
+I think a better solution might be to ask Pete editorially to change all
+declarations of tupling APIs to use the struct specifier instead of class.
 
    
-
       requires MoveConstructible<Cont> 
-     explicit priority_queue(const Compare& x = Compare(), Cont&& = Cont()); 
-
    
 
    
-   Don't require MoveConstructible when default constructing Cont.
-   Also missing semantics for move ctor.
+"metafunction forwarding" refers to the MPL metafunction protocol, where a
+metafunction result is declared as a nested typedef with the name "type",
+allowing metafunctions to be chained by means of inheritance.  It is a
+neater syntax than repeatedly declaring a typedef, and inheritance syntax is
+slightly nicer when it comes to additional typename keywords.
 
    
-
    
 
    
- [2009-03-21 Sat] Why are Allocators required to be CopyConstructible as
- opposed to MoveConstructible?
+The constrained template with an unconstrained base is a good observation
+though.
 
    
+
    
+
+
+
+
    Proposed resolution:
    
 
    
- [2009-03-21 Sat] p813 queue needs a separate default ctor (Cont needn't
- be MoveConstructible).  No documented semantics for move c'tor.  Or
- *any* of its 7 ctors!
+Add to 20.5.1 [tuple.general] p2 (Header <tuple> synopsis)
 
    
+
+
    // 20.5.2.3, tuple helper classes:
+template <IdentityOf T> class tuple_size; // undefined
+template <IdentityOf T> class tuple_size< const T > : tuple_size<T> {};
+template <IdentityOf T> class tuple_size< volatile T > : tuple_size<T> {};
+template <IdentityOf T> class tuple_size< const volatile T > : tuple_size<T> {};
+
+template <VariableType... Types> class tuple_size<tuple<Types...> >;
+
+template <size_t I, IdentityOf T> class tuple_element; // undefined
+template <size_t I, IdentityOf T> class tuple_element<I, const T>;
+template <size_t I, IdentityOf T> class tuple_element<I, volatile T>;
+template <size_t I, IdentityOf T> class tuple_element<I, const volatile T>;
+
+template <size_t I, VariableType... Types>
+  requires True<(I < sizeof...(Types))> class tuple_element<I, tuple<Types...> >;
+
    
+
 
    
- [2009-03-21 Sat] std::array should have constructors for C++0x,
- consequently must consider move construction.
+Add to 20.5.2.3 [tuple.helper]
 
    
-
 
    [
-2009-05-01 Daniel adds:
+(note that this solution relies on 'metafunction forwarding' to inherit the
+nested typename type)
 ]
    
 
 
-
    
-This could be done as part of 1035, which already handles
-deviation of std::array from container tables.
-
    
+
    template <class... Types>
+class tuple_size<tuple<Types...> >
+  : public integral_constant<size_t, sizeof...(Types)> { };
 
+template <size_t I, class... Types>
+requires True<(I < sizeof...(Types))>
+class tuple_element<I, tuple<Types...> > {
+public:
+  typedef TI type;
+};
+
+template <size_t I, IdentityOf T>
+  class tuple_element<I, const T> : add_const<tuple_element<I,T>> {};
+
+template <size_t I, IdentityOf T>
+  class tuple_element<I, volatile T> : add_volatile<tuple_element<I,T>> {};
+
+template <size_t I, IdentityOf T>
+  class tuple_element<I, const volatile T> : add_cv<tuple_element<I,T>> {};
+
    
+
+
+
+
+
+
    
+
    1119. tuple query APIs do not support references
    
+
    Section: 20.5.2.3 [tuple.helper] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-05-23  Last modified: 2009-05-24
    
+
    View other active issues in [tuple.helper].
    
+
    View all other issues in [tuple.helper].
    
+
    View all issues with New status.
    
+
    Discussion:
    
 
    
- [2009-03-21 Sat] p622 all messed up.
-
    
-
    
-
    
-   para 8 "implementation-defined" is the wrong term; should be "see
-   below" or something.  
+The tuple query APIs tuple_size and
+tuple_element do not support references-to-tuples.  This can be
+annoying when a template deduced a parameter type to be a reference,
+which must be explicitly stripped with remove_reference before calling
+these APIs.
 
    
 
    
-   para 12 "will be selected" doesn't make any sense because we're not
-   talking about actual arg types.
+I am not proposing a resolution at this point, as there is a
+combinatorial explosion with lvalue/rvalue references and
+cv-qualification (see previous issue) that suggests some higher
+refactoring is in order.  This might be something to kick back over to
+Core/Evolution.
 
    
 
    
-   paras 9-13 need to be totally rewritten for concepts.
+Note that we have the same problem in numeric_limits.
 
    
-
    
 
+
+
    Proposed resolution:
    
+
+
+
+
+
+
    
+
    1120. New type trait - remove_all
    
+
    Section: 20.6 [meta] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-05-23  Last modified: 2009-05-24
    
+
    View other active issues in [meta].
    
+
    View all other issues in [meta].
    
+
    View all issues with New status.
    
+
    Discussion:
    
 
    
- [2009-03-21 Sat] Null pointer comparisons (p587) have all become
- unconstrained.  Need to fix that
-
    
-
    
- [2009-03-21 Sat] mem_fun_t etc. definition doesn't match declaration.
-  We think CopyConstructible is the right reqt.
+Sometimes it is necessary to remove all qualifiers from a type before
+passing on to a further API.  A good example would be calling the
+tuple query APIs tuple_size or tuple_element
+with a deduced type inside a function template.  If the deduced type is
+cv-qualified or a reference then the call will fail.  The solution is to
+chain calls to
+remove_cv<remove_reference<T>::type>::type, and
+note that the order matters.
 
    
 
    
- make_pair needs Constructible<V1, T1&&> requirements!
+Suggest it would be helpful to add a new type trait,
+remove_all, that removes all top-level qualifiers from a type
+i.e. cv-qualification and any references.  Define the term in such a way
+that if additional qualifiers are added to the language, then
+remove_all is defined as stripping those as well.
 
    
+
+
+
    Proposed resolution:
    
+
+
+
+
+
+
    
+
    1121. Support for multiple arguments
    
+
    Section: 20.4.2 [ratio.arithmetic] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-05-25  Last modified: 2009-05-25
    
+
    View all other issues in [ratio.arithmetic].
    
+
    View all issues with New status.
    
+
    Discussion:
    
 
    
- make_tuple needs something similar
+Both add and multiply could sensibly be called with more than two arguments.
+The variadic template facility makes such declarations simple, and is likely
+to be frequently wrapped by end users if we do not supply the variant
+ourselves.
 
    
 
    
- tuple bug in synopsis:
+We deliberately ignore divide at this point as it is not transitive.
+Likewise, subtract places special meaning on the first argument so I do not
+suggest extending that immediately.  Both could be supported with analogous
+wording to that for add/multiply below.
 
    
-
       template <class... UTypes>
-   requires Constructible<Types, const UTypes&>...
-   template <class... UTypes>
-   requires Constructible<Types, RvalueOf<UTypes>::type>...
-
    
 
    
-   Note: removal of MoveConstructible requirements in std::function makes
-   these routines unconstrained!
+Note that the proposed resolution is potentially incompatible with that
+proposed for 921, although the addition of the typedef to ratio would be
+equally useful.
 
    
-
    
 
+
+
    Proposed resolution:
    
 
    [
-2009-05-02 Daniel adds:
+note that this wording relies on 'metafunction forwarding' as described by
+Boost MPL
 ]
    
 
 
-
    
-This part of the issue is already covered by 1077.
-
    
+
    
+20.4 [ratio] p3 synopsis: change
+
    
+
+
    // ratio arithmetic
+template <class R1, class R2, class ... RList> struct ratio_add;
+template <class R1, class R2> struct ratio_subtract;
+template <class R1, class R2, class ... RList> struct ratio_multiply;
+template <class R1, class R2> struct ratio_divide;
+
    
 
 
    
- these unique_ptr constructors are broken [ I think this is covered in "p622 all messed up" ]
+20.4.2 [ratio.arithmetic] p1: change
 
    
-
     unique_ptr(pointer p, implementation-defined d);
- unique_ptr(pointer p, implementation-defined d);
+
+
    template <class R1, class R2, class ... RList> struct ratio_add
+  : ratio_add< R1, ratio_add<R2, RList...>> {
+};
+
+template <class R1, class R2> struct ratio_add<R1, R2> {
+  typedef see below type;
+};
 
    
+
+
 
    
- multimap range constructor should not have MoveConstructible<value_type> requirement.
+20.4.2 [ratio.arithmetic] p3: change
 
    
-
    
-   same with insert(..., P&&); multiset has the same issue, as do
-   unordered_multiset and unordered_multimap. Review these!
-
    
 
-
    
+
    template <class R1, class R2, class ... RList> struct ratio_multiply
+  : ratio_multiply< R1, ratio_ multiply <R2, RList...>> {
+};
 
-
    [
-Batavia (2009-05):
-]
    
+template <class R1, class R2> struct ratio_ multiply<R1, R2> {
+  typedef see below type;
+};
+
    
 
-
    
-Move to Open, pending proposed wording from Dave for further review.
-
    
+
+
+
+
+
+
    
+
    1122. Ratio values should be constexpr
    
+
    Section: 20.4.1 [ratio.ratio] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-05-25  Last modified: 2009-05-25
    
+
    View other active issues in [ratio.ratio].
    
+
    View all other issues in [ratio.ratio].
    
+
    View all issues with New status.
    
+
    Discussion:
    
+
    
+The values num and den in the ratio template
+should be declared constexpr.
+
    
 
 
 
    Proposed resolution:
    
 
    
+20.4.1 [ratio.ratio]
 
    
 
+
    namespace std {
+  template <intmax_t N, intmax_t D = 1>
+  class ratio {
+  public:
+    static constexpr intmax_t num;
+    static constexpr intmax_t den;
+  };
+}
+
    
+
+
 
 
 
 
 
    
-
    1100. auto_ptr to unique_ptr conversion
    
-
    Section: D.9 [depr.auto.ptr] Status: Tentatively Ready
- Submitter: Howard Hinnant Opened: 2009-04-25  Last modified: 2009-05-23
    
-
    View all issues with Tentatively Ready status.
    
+
    1123. no requirement that standard streams be flushed
    
+
    Section: 27.5.2.1.6 [ios::Init] Status: New
+ Submitter: James Kanze Opened: 2009-05-14  Last modified: 2009-05-30
    
+
    View all other issues in [ios::Init].
    
+
    View all issues with New status.
    
 
    Discussion:
    
 
    
-Message c++std-lib-23182 led to a discussion in which several people
-expressed interest in being able to convert an auto_ptr to a
-unique_ptr without the need to call release.  Below is
-wording to accomplish this.
+As currently formulated, the standard doesn't require that there 
+is ever a flush of cout, etc.  (This implies, for example, that 
+the classical hello, world program may have no output.)  In the 
+current draft
+(N2798),
+there is a requirement that the objects 
+be constructed before main, and before the dynamic 
+initialization of any non-local objects defined after the 
+inclusion of <iostream> in the same translation unit.  The only 
+requirement that I can find concerning flushing, however, is in 
+27.5.2.1.6 [ios::Init], where the destructor of the last 
+std::ios_base::Init object flushes.  But there is, as far as I 
+can see, no guarantee that such an object ever exists. 
+
    
+
    
+Also, the wording in  [iostreams.objects] says that:
+
    
+
    
+The objects 
+are constructed and the associations are established at some 
+time prior to or during the first time an object of class 
+ios_base::Init is constructed, and in any case before the body 
+of main begins execution.
+
    
+
    
+In 27.5.2.1.6 [ios::Init], however, as an 
+effect of the constructor, it says that
 
    
+
    
+If init_cnt is zero, 
+the function stores the value one in init_cnt, then constructs 
+and initializes the objects cin, cout, cerr, clog 
+wcin, wcout, wcerr, and wclog"
+
    
 
-
    [
-Batavia (2009-05):
-]
    
+
    
+which seems to forbid earlier 
+construction. 
+
    
 
-
    
 
    
-Pete believes it not a good idea to separate parts of a class's definition.
-Therefore, if we do this,
-it should be part of unique-ptr's specification.
+(Note that with these changes, the exposition only "static 
+int init_cnt" in ios_base::Init can be dropped.) 
 
    
 
    
-Alisdair believes the lvalue overload may be not necessary.
+Of course, a determined programmer can still inhibit the 
+flush with things like: 
 
    
+
    new std::ios_base::Init ;       //  never deleted 
+
    
 
    
-Marc believes it is more than just sugar,
-as it does ease the transition to unique-ptr.
+or (in a function): 
 
    
+
    std::ios_base::Init ensureConstruction ; 
+//  ... 
+exit( EXIT_SUCCESS ) ; 
+
    
 
    
-We agree with the resolution as presented.
-Move to Tentatively Ready.
+Perhaps some words somewhere to the effect that all 
+std::ios_base::Init objects should have static lifetime 
+would be in order. 
 
    
-
    
 
 
 
    Proposed resolution:
    
 
    
-Add to D.9 [depr.auto.ptr]:
+Change 27.4 [iostream.objects]/2:
+
    
+
+
    
+-2- The objects are constructed and the associations are established at
+some time prior to or during the first time an object of class
+ios_base::Init is constructed, and in any case before the body
+of main begins execution.292 The objects are not destroyed
+during program execution.293
+If a translation unit includes
+<iostream> or explicitly constructs an
+ios_base::Init object, these stream objects shall be
+constructed before dynamic initialization of non-local objects defined
+later in that translation unit.
+The results of including <iostream> in a translation
+unit shall be as if <iostream> defined an instance of
+ios_base::Init with static lifetime. Similarly, the entire
+program shall behave as if there were at least one instance of
+ios_base::Init with static lifetime.
+
    
+
+
    
+Change 27.5.2.1.6 [ios::Init]/3:
 
    
 
 
    
-
    
-The following unique_ptr constructors are in addition to those specified
-in 20.8.12.2.1 [unique.ptr.single.ctor].
-
    
-
    template <class T, class D>
-class unique_ptr
-{
-public:
-    template <class U>
-      requires SameType<D, default_delete<T>>
-            && Convertible<U*, T*>
-      unique_ptr(auto_ptr<U>& u);
-    template <class U>
-      requires SameType<D, default_delete<T>>
-            && Convertible<U*, T*>
-      unique_ptr(auto_ptr<U>&& u);
-};
+
    Init();
 
    
-
    
-Effects: Constructs a unique_ptr with u.release().
-
    
+
    
+-3- Effects: Constructs an object of class Init. 
+If init_cnt is zero, the function stores the value one in
+init_cnt, then constructs and initializes the objects
+cin, cout, cerr, clog (27.4.1),
+wcin, wcout, wcerr, and wclog
+(27.4.2). In any case, the function then adds one to the value stored in
+init_cnt.
+Constructs and initializes the objects cin, cout,
+cerr, clog, wcin, wcout,
+wcerr and wclog if they have not already been
+constructed and initialized.
+
    
+
    
 
 
    
-Postconditions: get() ==  the value u.get() had before
-the construciton, modulo any required offset adjustments resulting from the cast from
-U* to T*.  u.get() == nullptr.
+Change 27.5.2.1.6 [ios::Init]/4:
 
    
 
-
    
-Throws: nothing.
-
    
+
    
+
    ~Init();
+
    
+
    
+-4- Effects: Destroys an object of class Init.
+The function subtracts one from the value stored in init_cnt and,
+if the resulting stored value is one,
+If there are no other instances of the class still in
+existance,
+calls cout.flush(),
+cerr.flush(), clog.flush(), wcout.flush(),
+wcerr.flush(), wclog.flush().
+
    
 
    
 
 
@@ -34163,71 +28291,47 @@ the construciton, modulo any required offset adjustments resulting from the cast
 
 
 
    
-
    1101. unique requirements
    
-
    Section: 25.4.9 [alg.unique] Status: Tentatively NAD Editorial
- Submitter: Howard Hinnant Opened: 2009-04-25  Last modified: 2009-05-23
    
-
    View other active issues in [alg.unique].
    
-
    View all other issues in [alg.unique].
    
-
    View all issues with Tentatively NAD Editorial status.
    
+
    1125. ostream_iterator does not work with movable types
    
+
    Section: 24.6.2.2 [ostream.iterator.ops] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-05-28  Last modified: 2009-05-30
    
+
    View all issues with New status.
    
 
    Discussion:
    
 
    
-From Message c++std-core-14160 Howard wrote:
+ostream_iterator has not been updated to support moveable types, in a
+similar manner to the insert iterators.
+Note that this is not a problem for ostreambuf_iterator, as the types it is
+restricted to dealing with do not support extra-efficient moving.
 
    
 
-
    
-It was the intent of the rvalue reference proposal for unique to only require MoveAssignable:
-N1860.
-
    
 
+
    Proposed resolution:
    
 
    
-And Pete replied:
+Add second operator= overload to class template ostream_iterator
+in 24.6.2 [ostream.iterator], para 2:
 
    
 
-
    
-That was overridden by the subsequent changes made for concepts in
-N2573,
-which reimposed the C++03 requirements.
-
    
+
    ostream_iterator<T,charT,traits>& operator=(const T& value);
+ostream_iterator<T,charT,traits>& operator=(T&& value);
+
    
 
 
    
-My impression is that this overwrite was a simple (unintentional) mistake.
-Wording below to correct it.
+Add a new paragraph: in 24.6.2.2 [ostream.iterator.ops]:
 
    
 
-
    [
-Batavia (2009-05):
-]
    
-
+
    
+
    ostream_iterator& operator=(T&& value);
+
    
 
    
 
    
-Howard notes this issue resolves a discrepancy between the synopsis
-and the description.
-
    
-
    
-Move to NAD Editorial.
-
    
-
    
-
-
-
    Proposed resolution:
    
-
    
-Change 25.4.9 [alg.unique]:
+-2- Effects:
 
    
-
-
    template<ForwardIterator Iter> 
-  requires OutputIterator<Iter, RvalueOf<Iter::reference>::type> 
-        && EqualityComparable<Iter::value_type> 
-  Iter unique(Iter first, Iter last); 
-
-template<ForwardIterator Iter, EquivalenceRelation<auto, Iter::value_type> Pred> 
-  requires OutputIterator<Iter, RvalueOf<Iter::reference>::type> 
-        && CopyConstructible<Pred> 
-  Iter unique(Iter first, Iter last, Pred pred);
+
    *out_stream << std::move(value);
+if(delim != 0)
+  *out_stream << delim;
+return (*this);
 
    
-
-
    
-Note that the synopsis in 25.2 [algorithms.syn] is already correct.
-
    
+
    
+
    
 
 
 
@@ -34235,375 +28339,206 @@ Note that the synopsis in 25.2 [algorithms.syn] is already correct.
 
 
 
    
-
    1102. std::vector's reallocation policy still unclear
    
-
    Section: 23.3.6.2 [vector.capacity] Status: Review
- Submitter: Daniel Krügler Opened: 2009-04-20  Last modified: 2009-05-23
    
-
    View all other issues in [vector.capacity].
    
-
    View all issues with Review status.
    
+
    1126. istreambuff_iterator::equal needs a const & parameter
    
+
    Section: 24.6.3.5 [istreambuf.iterator::equal] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-05-28  Last modified: 2009-05-30
    
+
    View all other issues in [istreambuf.iterator::equal].
    
+
    View all issues with New status.
    
 
    Discussion:
    
 
    
-I have the impression that even the wording of current draft
-N2857
-does insufficiently express the intent of vector's
-reallocation strategy. This has produced not too old library
-implementations which release memory in the clear() function
-and even modern articles about C++ programming cultivate
-the belief that clear is allowed to do exactly this. A typical
-example is something like this:
-
    
-
-
    const int buf_size = ...;
-std::vector<T> buf(buf_size);
-for (int i = 0; i < some_condition; ++i) {
-  buf.resize(buf_size);
-  write_or_read_data(buf.data());
-  buf.clear(); // Ensure that the next round get's 'zeroed' elements
-}
-
    
-
    
-where still the myth is ubiquitous that buf might be
-allowed to reallocate it's memory *inside* the for loop.
-
    
-
    
-IMO the problem is due to the fact, that
-
    
-
-
      
-
    1. 
-the actual memory-reallocation stability of std::vector
-is explained in 23.3.6.2 [vector.capacity]/3 and /6 which
-are describing just the effects of the reserve
-function, but in many examples (like above) there
-is no explicit call to reserve involved. Further-more
-23.3.6.2 [vector.capacity]/6 does only mention insertions
-and never mentions the consequences of erasing
-elements.
-
      2. 
-
    2. 
-
      
-the effects clause of std::vector's erase overloads in
-23.3.6.4 [vector.modifiers]/4 is silent about capacity changes. This
-easily causes a misunderstanding, because the counter
-parting insert functions described in 23.3.6.4 [vector.modifiers]/2
-explicitly say, that
+The equal member function of istreambuf_iterator is
+declared const, but takes its argument by non-const reference.
 
      
-
      
-Causes reallocation if the new size is greater than the
-old capacity. If no reallocation happens, all the iterators
-and references before the insertion point remain valid.
-
      
 
      
-It requires a complex argumentation chain about four
-different places in the standard to provide the - possibly
-weak - proof that calling clear() also does never change
-the capacity of the std::vector container. Since std::vector
-is the de-facto replacement of C99's dynamic arrays this
-type is near to a built-in type and it's specification should
-be clear enough that usual programmers can trust their
-own reading.
+This is not compatible with the operator== free function overload, which is
+defined in terms of calling equal yet takes both arguments by reference to
+const.
 
      
-
      3. 
-
    
 
 
    [
-Batavia (2009-05):
+The proposed wording is consistent with 110 with status TC1.
 ]
    
 
-
    
-
    
-Bill believes paragraph 1 of the proposed resolution is unnecessary
-because it is already implied (even if tortuously) by the current wording.
-
    
-
    
-Move to Review.
-
    
-
    
-
 
-
    Proposed resolution:
    
-
    [
-This is a minimum version. I also
-suggest that the wording explaining the allocation strategy
-of std::vector in 23.3.6.2 [vector.capacity]/3 and /6 is moved into
-a separate sub paragraph of 23.3.6.2 [vector.capacity] before
-any of the prototype's are discussed, but I cannot provide
-reasonable wording changes now
-]
    
 
 
-
      
-
    1. 
-
      
-Change 23.3.6.2 [vector.capacity]/6 as follows:
-
      
-
      
-It is guaranteed that no reallocation takes place during
-insertions or erasures that happen after a call
-to reserve() until the time when an insertion would make
-the size of the vector greater than the value of capacity().
-
      
-
      2. 
-
    2. 
+
      Proposed resolution:
      
 
      
-Change 23.3.6.4 [vector.modifiers]/4 as follows:
+Ammend in both:
      
+24.6.3 [istreambuf.iterator]
      
+24.6.3.5 [istreambuf.iterator::equal]
      
 
      
-
      
-Effects: The capacity shall remain unchanged and no reallocation shall
-happen.
-Invalidates iterators and references at or after the point
-of the erase.
-
      
-
      3. 
-
    
 
+
    bool equal(const istreambuf_iterator& b) const;
+
    
 
 
 
 
-
    
-
    1103. system_error constructor postcondition overly strict
    
-
    Section: 19.5.5.2 [syserr.syserr.members] Status: Tentatively Ready
- Submitter: Howard Hinnant Opened: 2009-04-25  Last modified: 2009-05-23
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
-
    
-19.5.5.2 [syserr.syserr.members] says:
-
    
 
-
    system_error(error_code ec, const string& what_arg);
-
    
-
    
-
    
-Effects: Constructs an object of class system_error.
-
    
-
    
-Postconditions: code() == ec and strcmp(runtime_error::what(), what_arg.c_str()) == 0.
-
    
-
    
-
    
 
+
    
+
    1129. istream(buf)_iterator should support literal sentinel value
    
+
    Section: 24.6.1.1 [istream.iterator.cons], 24.6.3 [istreambuf.iterator] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-05-30  Last modified: 2009-06-09
    
+
    View all issues with New status.
    
+
    Discussion:
    
 
    
-However the intent is for:
+istream_iterator and istreambuf_iterator should support literal sentinel
+values.  The default constructor is frequently used to terminate ranges, and
+could easily be a literal value for istreambuf_iterator, and
+istream_iterator when iterating value types.  A little more work using a
+suitably sized/aligned char-array for storage (or an updated component like
+boost::optional proposed for TR2) would allow istream_iterator to support
+constexpr default constructor in all cases, although we might leave this
+tweak as a QoI issue.  Note that requiring constexpr be supported also
+allows us to place no-throw guarantees on this constructor too.
 
    
 
-
    std::system_error se(std::errc::not_a_directory, "In FooBar");
-...
-se.what();  // returns something along the lines of:
-            //   "In FooBar: Not a directory"
-
    
-
-
    
-The way the constructor postconditions are set up now, to achieve both
-conformance, and the desired intent in the what() string, the
-system_error constructor must store "In FooBar" in the base class,
-and then form the desired output each time what() is called.  Or
-alternatively, store "In FooBar" in the base class, and store the desired
-what() string in the derived system_error, and override
-what() to return the string in the derived part.
-
    
+
    [
+2009-06-02 Daniel adds:
+]
    
 
-
    
-Both of the above implementations seem suboptimal to me.  In one I'm computing
-a new string every time what() is called.  And since what()
-can't propagate exceptions, the client may get a different string on different
-calls.
-
    
 
+
    
 
    
-The second solution requires storing two strings instead of one.
+I agree with the usefulness of the issue suggestion, but we need
+to ensure that istream_iterator can satisfy be literal if needed.
+Currently this is not clear, because 24.6.1 [istream.iterator]/3 declares
+a copy constructor and a destructor and explains their semantic in
+24.6.1.1 [istream.iterator.cons]/3+4.
 
    
-
 
    
-What I would like to be able to do is form the desired what() string
-once in the system_error constructor, and store that in the
-base class.  Now I'm:
+The prototype semantic specification is ok (although it seems
+somewhat redundant to me, because the semantic doesn't say
+anything interesting in both cases), but for support of trivial class
+types we also need a trivial copy constructor and destructor as of
+9 [class]/6. The current non-informative specification of these
+two special members suggests to remove their explicit declaration
+in the class and add explicit wording that says that if T is
+trivial a default constructed iterator is also literal, alternatively it
+would be possible to mark both as defaulted and add explicit
+(memberwise) wording that guarantees that they are trivial.
 
    
-
-
      
-
    1. Computing the desired what() only once.
      2. 
-
    2. The base class what() definition is sufficient and nothrow.
      3. 
-
    3. I'm not storing multiple strings.
      4. 
-
    
-
 
    
-This is smaller code, smaller data, and faster.
+Btw.: I'm quite sure that the istreambuf_iterator additions to
+ensure triviality are not sufficient as suggested, because the
+library does not yet give general guarantees that a defaulted
+special member declaration makes this member also trivial.
+Note that e.g. the atomic types do give a general statement!
 
    
-
 
    
-ios_base::failure has the same issue.
+Finally there is a wording issue: There does not exist something
+like a "literal constructor". The core language uses the term
+"constexpr constructor" for this.
 
    
-
-
    [
-Comments about this change received favorable comments from the system_error
-designers.
-]
    
-
-
-
    [
-Batavia (2009-05):
-]
    
-
-
-
    
 
    
-We agree with the proposed resolution.
+Suggestion:
 
    
+
      
+
    1. 
 
      
-Move to Tentatively Ready.
+Change 24.6.1 [istream.iterator]/3 as indicated:
 
      
-
    
-
-
-
    Proposed resolution:
    
+
    constexpr istream_iterator();
+istream_iterator(istream_type& s);
+istream_iterator(const istream_iterator<T,charT,traits,Distance>& x) = default;
+~istream_iterator() = default;
+
    
+
+
  • 
 
    
-In 19.5.5.2 [syserr.syserr.members], change the following constructor postconditions:
+Change 24.6.1.1 [istream.iterator.cons]/1 as indicated:
 
    
-
-
    
-
    system_error(error_code ec, const string& what_arg);
-
    
-
    
--2- Postconditions: code() == ec
-and strcmp(runtime_error::what(), what_arg.c_str()) == 0
-string(what()).find(what_arg) != string::npos.
-
    
-
-
    system_error(error_code ec, const char* what_arg);
+
    constexpr istream_iterator();
 
    
 
    
--4- Postconditions: code() == ec
-and strcmp(runtime_error::what(), what_arg) == 0
-string(what()).find(what_arg) != string::npos.
+-1- Effects: Constructs the end-of-stream iterator. If T is a literal type,
+then this constructor shall be a constexpr constructor.
 
    
-
-
    system_error(error_code ec);
-
    
-
    
--6- Postconditions: code() == ec
-and strcmp(runtime_error::what(), "".
 
    
-
-
    system_error(int ev, const error_category& ecat, const string& what_arg);
+
    • 
+
  • 
+
    
+Change 24.6.1.1 [istream.iterator.cons]/3 as indicated:
+
    
+
    istream_iterator(const istream_iterator<T,charT,traits,Distance>& x) = default;
 
    
 
    
--8- Postconditions: code() == error_code(ev, ecat)
-and strcmp(runtime_error::what(), what_arg.c_str()) == 0
-string(what()).find(what_arg) != string::npos.
+-3- Effects: Constructs a copy of x. If T is a literal type, then
+this constructor shall be a trivial copy constructor.
 
    
-
-
    system_error(int ev, const error_category& ecat, const char* what_arg);
-
    
-
    
--10- Postconditions: code() == error_code(ev, ecat)
-and strcmp(runtime_error::what(), what_arg) == 0
-string(what()).find(what_arg) != string::npos.
 
    
+
    • 
+
  • 
+
    
+Change 24.6.1.1 [istream.iterator.cons]/4 as indicated:
+
    
 
-
    system_error(int ev, const error_category& ecat);
+
    ~istream_iterator() = default;
 
    
 
    
--12- Postconditions: code() == error_code(ev, ecat)
-and strcmp(runtime_error::what(), "") == 0.
+-4- Effects: The iterator is destroyed. If T is a literal type, then
+this destructor shall be a trivial
+destructor.
 
    
-
 
    
-
+
    • 
+
  • 
 
    
-In 19.5.5.2 [syserr.syserr.members], change the description of what():
+Change 24.6.3 [istreambuf.iterator] before p. 1 as indicated:
 
    
 
-
    
-
    const char *what() const throw();
-
    
-
    
-
    
--14- Returns: An NTBS incorporating runtime_error::what() and
-code().message() the arguments supplied in the constructor.
-
    
-
    
-[Note: One possible implementation would be:
-The return NTBS might take the form: what_arg + ": " + code().message()
-
    
-
    
-if (msg.empty()) { 
-  try { 
-    string tmp = runtime_error::what(); 
-    if (code()) { 
-      if (!tmp.empty()) 
-        tmp += ": "; 
-      tmp += code().message(); 
-    } 
-    swap(msg, tmp); 
-  } catch(...) { 
-    return runtime_error::what(); 
-  } 
-return msg.c_str();
-
    
+
    constexpr istreambuf_iterator() throw();
+istreambuf_iterator(const istreambuf_iterator&)  throw() = default;
+~istreambuf_iterator()  throw() = default;
+
    
+
    • 
+
  • 
 
    
-— end note]
+Change 24.6.3 [istreambuf.iterator]/1 as indicated:
 
    
+
    
+[..] The default constructor istreambuf_iterator() and the constructor
+istreambuf_iterator(0) both
+construct an end of stream iterator object suitable for use as an
+end-of-range. All
+specializations of istreambuf_iterator shall have a trivial copy
+constructor, a constexpr default
+constructor and a trivial destructor.
 
    
+
    • 
+
 
    
 
-
    
-In 27.5.2.1.1 [ios::failure], change the synopsis:
-
    
-
-
    namespace std { 
-  class ios_base::failure : public system_error { 
-  public: 
-    explicit failure(const string& msg, const error_code& ec = io_errc::stream); 
-    explicit failure(const char* msg, const error_code& ec = io_errc::stream); 
-    virtual const char* what() const throw();
-  }; 
-}
-
    
 
+
    Proposed resolution:
    
 
    
-In 27.5.2.1.1 [ios::failure], change the description of the constructors:
+24.6.1 [istream.iterator] para 3
 
    
 
-
    
+
    constexpr istream_iterator();
+
    
 
-
    explicit failure(const string& msg, , const error_code& ec = io_errc::stream);
-
    
-
    
 
    
--3- Effects: Constructs an object of class failure
-by constructing the base class with msg and ec.
-
    
-
    
--4- Postcondition: code() == ec and strcmp(what(), msg.c_str()) == 0
+24.6.1.1 [istream.iterator.cons]
 
    
-
    
 
-
    explicit failure(const char* msg, const error_code& ec = io_errc::stream);
+
    constexpr istream_iterator();
 
    
 
    
-
    
--5- Effects: Constructs an object of class failure
-by constructing the base class with msg and ec.
-
    
-
    
--6- Postcondition: code() == ec and strcmp(what(), msg) == 0
-
    
+-1- Effects: Constructs the end-of-stream iterator.
+If T is a literal type, then this constructor shall
+be a literal constructor.
 
    
-
 
    
 
 
    
-In 27.5.2.1.1 [ios::failure], remove what (the base class definition
-need not be repeated here).
+24.6.3 [istreambuf.iterator]
 
    
 
-
    
-
    const char* what() const;
-
    
-
    
--7- Returns: The message msg with which the exception was created.
-
    
-
-
    
+
    constexpr istreambuf_iterator() throw();
+
    
 
 
 
@@ -34611,1040 +28546,876 @@ need not be repeated here).
 
 
 
    
-
    1104. basic_ios::move should accept lvalues
    
-
    Section: 27.5.4.2 [basic.ios.members] Status: Review
- Submitter: Howard Hinnant Opened: 2009-04-25  Last modified: 2009-05-23
    
-
    View other active issues in [basic.ios.members].
    
-
    View all other issues in [basic.ios.members].
    
-
    View all issues with Review status.
    
+
    1130. copy_exception name misleading
    
+
    Section: 18.8.5 [propagation] Status: New
+ Submitter: Peter Dimov Opened: 2009-05-13  Last modified: 2009-06-02
    
+
    View other active issues in [propagation].
    
+
    View all other issues in [propagation].
    
+
    View all issues with New status.
    
 
    Discussion:
    
 
    
-With the rvalue reference changes in
-N2844
-basic_ios::move no longer has the most convenient signature:
+The naming of std::copy_exception misleads almost everyone
+(experts included!) to think that it is the function that copies an
+exception_ptr:
 
    
 
-
    void move(basic_ios&& rhs);
+
    exception_ptr p1 = current_exception();
+exception_ptr p2 = copy_exception( p1 );
 
    
 
 
    
-This signature should be changed to accept lvalues.  It does not need to be
-overloaded to accept rvalues.  This is a special case that only derived clients
-will see.  The generic move still needs to accept rvalues.
+But this is not at all what it does. The above actually creates an
+exception_ptr p2 that contains a copy of p1, not of
+the exception to which p1 refers!
 
    
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
 
    
-Tom prefers, on general principles, to provide both overloads.
-Alisdair agrees.
+This is, of course, all my fault; in my defence, I used copy_exception
+because I was unable to think of a better name.
 
    
 
    
-Howard points out that there is no backward compatibility issue
-as this is new to C++0X.
+But I believe that, based on what we've seen so far, any other name would be better.
 
    
 
    
-We agree that both overloads should be provided,
-and Howard will provide the additional wording.
-Move to Open.
+Therefore, I propose copy_exception to be renamed to
+create_exception:
 
    
-
    
-
-
    [
-2009-05-23 Howard adds:
-]
    
-
-
-
    
-Added overload, moved to Review.
-
    
-
 
+
    template<class E> exception_ptr create_exception(E e);
+
    
 
-
    Proposed resolution:
    
 
    
-Add a signature to the existing prototype in the synopsis of 27.5.4 [ios]
-and in 27.5.4.2 [basic.ios.members]:
+with the following explanatory paragraph after it:
 
    
 
-
    void move(basic_ios& rhs);
-void move(basic_ios&& rhs);
-
    
-
-
-
-
-
-
    
-
    1105. Shouldn't Range be an auto concept
    
-
    Section: 24.2.8 [iterator.concepts.range] Status: Open
- Submitter: David Abrahams Opened: 2009-04-23  Last modified: 2009-05-23
    
-
    View all issues with Open status.
    
-
    Discussion:
    
+
    
+Creates an exception_ptr that refers to a copy of e.
+
    
 
 
    [
-2009-04-26 Herb adds:
+2009-05-13 Daniel adds:
 ]
    
 
 
 
    
 
    
-Here's a common example: We have many ISV customers who have built lots of
-in-house STL-like containers. Imagine that, for the past ten years, the user
-has been happily using his XYZCorpContainer<T> that has begin() and end()
-and an iterator typedef, and indeed satisfies nearly all of Container,
-though maybe not quite all just like valarray. The user upgrades to a
-range-enabled version of a library, and now lib_algo( xyz.begin(), xyz.end());
-no longer works -- compiler error.
+What about
 
    
+
    make_exception_ptr
+
    
 
    
-Even though XYZCorpContainer matches the pre-conceptized version of the
-algorithm, and has been working for years, it appears the user has to write
-at least this:
+in similarity to make_pair and make_tuple, make_error_code and
+make_error_condition, or make_shared? Or, if a stronger symmetry to
+current_exception is preferred:
 
    
-
    template<class T> concept_map Range<XYZCorpContainer<T>> {};
 
-template<class T> concept_map Range<const XYZCorpContainer<T>> {};
+
    make_exception
 
    
 
    
-Is that correct?
-
    
-
    
-But he may actually have to write this as we do for initializer list:
+We have not a single create_* function in the library, it was always
+make_* used.
 
    
-
    template<class T>
-concept_map Range<XYZCorpContainer<T>> {
-   typedef T* iterator;
-   iterator begin(XYZCorpContainer<T> c) { return c.begin(); }
-   iterator end(XYZCorpContainer<T> c) { return c.end(); }
-};
+
    
+
+
    [
+2009-05-13 Peter adds:
+]
    
 
-template<class T>
-concept_map Range<const XYZCorpContainer<T>> {
-   typedef T* iterator;
-   iterator begin(XYZCorpContainer<T> c) { return c.begin(); }
-   iterator end(XYZCorpContainer<T> c) { return c.end(); }
-};
-
    
 
+
    
+make_exception_ptr works for me.
 
    
 
 
    [
-2009-04-28 Alisdair adds:
+2009-06-02 Thomas J. Gritzan adds:
 ]
    
 
 
 
    
 
    
-I recommend NAD, although remain concerned about header organisation.
-
    
-
    
-A user container will satisfy the MemberContainer concept, which IS auto.
-There is a concept_map for all MemberContainers to Container, and then a
-further concept_map for all Container to Range, so the stated problem is not
-actually true.  User defined containers will automatically match the Range
-concept without explicitly declaring a concept_map.
-
    
-
    
-The problem is that they should now provide an additional two headers,
-<iterator_concepts> and <container_concepts>.
- The only difference from
-making Range an auto concept would be this reduces to a single header,
-<iterator_concepts>.
+To avoid surprises and unwanted recursion, how about making a call to
+std::make_exception_ptr with an exception_ptr illegal?
 
    
 
    
-I am strongly in favour of any resolution that tackles the issue of
-explicitly requiring concept headers to make these concept maps available.
+It might work like this:
 
    
+
    template<class E>
+exception_ptr make_exception_ptr(E e);
+template<>
+exception_ptr make_exception_ptr<exception_ptr>(exception_ptr e) = delete;
+
    
 
    
 
-
    [
-Batavia (2009-05):
-]
    
 
-
    
-
    
-We observe there is a recent paper by Bjarne that overlaps this issue.
-
    
+
+
    Proposed resolution:
    
 
    
-Alisdair continues to recommend NAD.
+Change 18.8.5 [propagation]:
 
    
+
+
    
+
    template<class E> exception_ptr copy_exceptionmake_exception_ptr(E e);
+
    
+
+
    
 
    
-Move to Open, and recommend the issue be deferred until after the next
-Committee Draft is issued.
+-11- Effects: Creates an exception_ptr that refers
+to a copy of e, as if
 
    
+
+
    try {
+  throw e;
+} catch(...) {
+  return current_exception();
+}
+
    
+
+
    ...
    
 
    
 
+
    
 
-
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1106. Multiple exceptions from connected shared_future::get()?
    
-
    Section: 30.6.5 [future.shared_future] Status: Open
- Submitter: Thomas J. Gritzan Opened: 2009-04-03  Last modified: 2009-05-23
    
-
    View other active issues in [future.shared_future].
    
-
    View all other issues in [future.shared_future].
    
-
    View all issues with Open status.
    
+
    1131. C++0x does not need alignment_of
    
+
    Section: 20.6.4.3 [meta.unary.prop] Status: New
+ Submitter: Niels Dekker Opened: 2009-06-01  Last modified: 2009-06-02
    
+
    View other active issues in [meta.unary.prop].
    
+
    View all other issues in [meta.unary.prop].
    
+
    View all issues with New status.
    
 
    Discussion:
    
 
    
-It is not clear, if multiple threads are waiting in a 
-shared_future::get() call, if each will rethrow the stored exception.
+The alignment_of template is no longer necessary, now that the
+core language will provide alignof. Scott Meyers raised this
+issue at comp.std.c++,
+C++0x: alignof vs. alignment_of,
+May 21, 2009.  In a reply, Daniel Krügler pointed out that
+alignof was added to the working paper after
+alignment_of. So it appears that alignment_of is only
+part of the current Working Draft 
+(N2857)
+because it is in TR1.
 
    
 
    
-Paragraph 9 reads: 
+Having both alignof and alignment_of would cause
+unwanted confusion. In general, I think TR1 functionality should not be
+brought into C++0x if it is entirely redundant with other C++0x language
+or library features.
 
    
-
    
-Throws: the stored exception, if an exception was stored and not 
-retrieved before.
-
    
+
+
+
    Proposed resolution:
    
 
    
-The "not retrieved before" suggests that only one exception is thrown, 
-but one exception for each call to get() is needed, and multiple calls 
-to get() even on the same shared_future object seem to be allowed. 
+Remove from Header <type_traits> synopsis 20.6.2 [meta.type.synop]:
 
    
+
    template <class T> struct alignment_of;
+
    
+
 
    
-I suggest removing "and not retrieved before" from the Throws paragraph. 
-I recommend adding a note that explains that multiple calls on get() are 
-allowed, and each call would result in an exception if an exception was 
-stored. 
+Remove the first row of Table 34 ("Type property queries"), from
+Type properties 20.6.4.3 [meta.unary.prop]:
 
    
+
    
+
+
+
+
+
+
+
    Table 34 -- Type property queries
    template <class T> struct alignment_of;alignof(T).
    
+Precondition: T shall be a complete type, a reference
+type, or an array of unknown bound, but shall not be a function type or
+(possibly cv-qualified) void.
+
    
+
    
 
-
    [
-Batavia (2009-05):
-]
    
-
+
    
+Change text in Table 41 ("Other transformations"), from Other
+transformations 20.6.7 [meta.trans.other], as follows:
+
    
 
    
+
+
+
+
+
+
    Table 41 -- Other transformations
    ...
+ Align shall be equal to 
+ alignment_of<T>::value
+ alignof(T)
+  for some type T or to default-alignment.
+...
    
+
    
+
+
+
+
+
+
    
+
    1132. JP-30: nested exceptions
    
+
    Section: 18.8.6 [except.nested] Status: New
+ Submitter: Seiji Hayashida Opened: 2009-06-01  Last modified: 2009-06-02
    
+
    View other active issues in [except.nested].
    
+
    View all other issues in [except.nested].
    
+
    View all issues with New status.
    
+
    Discussion:
    
+
    Addresses JP 30
    
+
 
    
-We note there is a pending paper by Detlef
-on such future-related issues;
-we would like to wait for his paper before proceeding.
+C++0x nested_exception cannot handle a structured exception well. The
+following codes show two types of tree structured exception handling.
 
    
 
    
-Alisdair suggests we may want language to clarify that this
-get() function can be called from several threads
-with no need for explicit locking.
+The first one is based on nested_exception in C++0x,
+while the second one is based on my library trickerr.h (in Japanese).
+http://tricklib.com/cxx/dagger/trickerr.h
 
    
 
    
-Move to Open.
+Assume that Function A() calls two sub functions A_a() and A_b(), both might
+throw tree structured exceptions, and A_b() must be called even if A_a()
+throws an exception.
 
    
-
    
-
-
-
    Proposed resolution:
    
 
    
-Change 30.6.5 [future.shared_future]:
+List A (code of tree structured exception handling based on nested_exception
+in C++0x)
 
    
 
-
    const R& shared_future::get() const; 
-R& shared_future<R&>::get() const; 
-void shared_future<void>::get() const;
-
    
-
    
-
    ...
    
+
    void A()
+{
+    try
+    {
+        std::vector<exception_ptr> exception_list;
+        try
+        {
+            // A_a() does a similar processing as A().
+            A_a();
+        }
+        catch(...)
+        {
+            exception_list.push_back(current_exception());
+        }
+
+        // ***The processing A() has to do even when A_a() fails. ***
+        try
+        {
+            // A_b() does a similar processing as A().
+            A_b();
+        }
+        catch(...)
+        {
+            exception_list.push_back(current_exception());
+        }
+        if (!exception_list.empty())
+        {
+            throw exception_list;
+        }
+    }
+    catch(...)
+    {
+        throw_with_nested(A_exception("someone error"));
+    }
+}
+void print_tree_exception(exception_ptr e, const std::string & indent ="")
+{
+    const char * indent_unit = " ";
+    const char * mark = "- ";
+    try
+    {
+        rethow_exception(e);
+    }
+    catch(const std::vector<exception_ptr> e)
+    {
+        for(std::vector<exception_ptr>::const_iterator i = e.begin(); i!=e.end(); ++i)
+        {
+            print_tree_exception(i, indent);
+        }
+    }
+    catch(const std::nested_exception  e)
+    {
+        print_tree_exception(evil_i(e), indent +indent_unit);
+    }
+    catch(const std::exception e)
+    {
+        std::cout << indent << mark << e.what() << std::endl;
+    }
+    catch(...)
+    {
+        std::cout << indent << mark << "unknown exception" << std::endl;
+    }
+}
+int main(int, char * [])
+{
+    try
+    {
+        A();
+    }
+    catch()
+    {
+        print_tree_exception(current_exception());
+    }
+    return EXIT_SUCCESS;
+}
+
    
+
 
    
--9- Throws: the stored exception, if an exception was stored and not retrieved before.
-
-[Note: Multiple calls on get() are 
-allowed, and each call would result in an exception if an exception was 
-stored. — end note]
-
+List B ( code of tree structured exception handling based on trickerr.h. )
+"trickerr.h" (in Japanese), refer to:
+http://tricklib.com/cxx/dagger/trickerr.h.
 
    
-
    
-
    
 
+
    void A()
+{
+    tricklib::error_listener_type error_listener;
+    // A_a() is like A(). A_a() can throw tree structured exception.
+    A_a();
 
+    // *** It must do process so that A_a() throws exception in A(). ***
+    // A_b() is like A(). A_b() can throw tree structured exception.
+    A_b();
 
+    if (error_listener.has_error()) // You can write this "if block" in destructor
+                                    //  of class derived from error_listener_type.
+    {
+        throw_error(new A_error("someone error",error_listener.listener_off().extract_pending_error()));
+    }
+}
+void print_tree_error(const tricklib::error_type &a_error, const std::string & indent = "")
+{
+    const char * indent_unit = " ";
+    const char * mark = "- ";
 
+    tricklib::error_type error = a_error;
+    while(error)
+    {
+        std::cout << indent << mark << error->message << std::endl;
+        if (error->children)
+        {
+            print_tree_error(error->children, indent +indent_unit);
+        }
+        error = error->next;
+    }
+}
+int main(int, char * [])
+{
+    tricklib::error_thread_power error_thread_power_on; // This object is necessary per thread.
 
+    try
+    {
+        A();
+    }
+    catch(error_type error)
+    {
+        print_tree_error(error);
+    }
+    catch(...)
+    {
+        std::cout << "- unknown exception" << std::endl;
+    }
+    return EXIT_SUCCESS;
+}
+
    
 
-
    
-
    1107. constructor shared_future(unique_future) by value?
    
-
    Section: 30.6.5 [future.shared_future] Status: Tentatively Ready
- Submitter: Thomas J. Gritzan Opened: 2009-04-03  Last modified: 2009-05-23
    
-
    View other active issues in [future.shared_future].
    
-
    View all other issues in [future.shared_future].
    
-
    View all issues with Tentatively Ready status.
    
-
    Discussion:
    
 
    
-In the shared_future class definition in 30.6.5 [future.shared_future]
-the move constructor 
-that constructs a shared_future from an unique_future receives the 
-parameter by value. In paragraph 3, the same constructor receives it as 
-const value. 
+Prospect
 
    
-
 
    
-I think that is a mistake and the constructor should take a r-value 
-reference: 
+We will focus on the method A() since the other methods, also main(), occur
+only once respectively.
 
    
 
-
    shared_future(unique_future<R>&& rhs);
-
    
-
-
    [
-Batavia (2009-05):
-]
    
+
      
+
    • 
+ In the List A above (of the nested exception handling), it is hard to
+ find out an active reason to use the nested exception handling at this
+ scene. Rather, we can take a simpler description by throwing the entire
+ exception_list directly to the top level.
+
      • 
+
    • 
+ The code in the same example gives us a kind of redundant impression,
+ which might have come from the fact that the try-throw-catch framework does
+ not assume a tree structured exception handling.
+
      • 
+
    
 
-
    
 
    
-We agree with the proposed resolution.
+According to the above observation, we cannot help concluding that it is not
+so easy to use the nested_exception handling as a tree structured exception
+handling mechanism in a practical sense.
 
    
 
    
-Move to Tentatively Ready.
+This text is based on the web page below (in Japanese).
+http://d.hatena.ne.jp/wraith13/20081231/1230715424
 
    
-
    
 
 
 
    Proposed resolution:
    
 
    
-Change the synopsis in 30.6.5 [future.shared_future]:
-
    
-
-
    shared_future(unique_future<R>&& rhs);
-
    
-
-
    
-Change the definition of the constructor in 30.6.5 [future.shared_future]:
 
    
 
-
    shared_future(const unique_future<R>&& rhs);
-
    
-
-
 
 
 
 
 
    
-
    1108. thread.req.exception overly constrains implementations
    
-
    Section: 30.2.2 [thread.req.exception] Status: Open
- Submitter: Christopher Kohlhoff Opened: 2009-04-25  Last modified: 2009-05-23
    
-
    View all issues with Open status.
    
+
    1133. Does N2844 break current specification of list::splice?
    
+
    Section: 23.3.3.5 [forwardlist.ops], 23.3.4.4 [list.ops] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-05-09  Last modified: 2009-06-09
    
+
    View other active issues in [forwardlist.ops].
    
+
    View all other issues in [forwardlist.ops].
    
+
    View all issues with New status.
    
 
    Discussion:
    
 
    
-The current formulation of 30.2.2 [thread.req.exception]/2 reads:
+IIUC,
+N2844
+means that lvalues will no longer bind to rvalue references.
+Therefore, the current specification of list::splice (list
+operations 23.3.4.4 [list.ops]) will be a breaking change of behaviour for existing
+programs.  That is because we changed the signature to swallow via an rvalue
+reference rather than the lvalue reference used in 03.
 
    
-
    
-The error_category of the error_code reported by such an
-exception's code() member function is as specified in the error
-condition Clause.
-
    
 
    
-This constraint on the code's associated error_categor means an
-implementation must perform a mapping from the system-generated
-error to a generic_category() error code. The problems with this
-include:
+Retaining this form would be safer, requiring an explicit move when splicing
+from lvalues.  However, this will break existing programs.
+We have the same problem with forward_list, although without the risk of
+breaking programs so here it might be viewed as a positive feature.
 
    
-
-
      
-
    • 
-The mapping is always performed, even if the resultant value is
- never used.
-
      • 
-
    • 
 
      
-The original error produced by the operating system is lost.
+The problem signatures:
 
      
-
      • 
-
    
+
    void splice_after(const_iterator position, forward_list<T,Alloc>&& x);
+void splice_after(const_iterator position, forward_list<T,Alloc>&& x,
+                  const_iterator i);
+void splice_after(const_iterator position, forward_list<T,Alloc>&& x,
+                  const_iterator first, const_iterator last);
+
+void splice(const_iterator position, list<T,Alloc>&& x);
+void splice(const_iterator position, list<T,Alloc>&& x,
+            const_iterator i);
+void splice(const_iterator position, list<T,Alloc>&& x,
+            const_iterator first, const_iterator last);
+
    
+
+Possible resolutions:
+
 
    
-The latter was one of Peter Dimov's main objections (in a private
-email discussion) to the original error_code-only design, and led to
-the creation of error_condition in the first place. Specifically,
-error_code and error_condition are intended to perform the following
-roles:
+Option A.	Add an additional (non-const) lvalue-reference
+overload in each case
 
    
-
      
-
    • 
-error_code holds the original error produced by the operating
- system.
-
      • 
-
    • 
-error_condition and the generic category provide a set of well
- known error constants that error codes may be tested against.
-
      • 
-
    
 
    
-Any mapping determining correspondence of the returned error code to
-the conditions listed in the error condition clause falls under the
-"latitude" granted to implementors in 19.5.1.5 [syserr.errcat.objects].
-(Although obviously their latitude is restricted a little by the
-need to match the right error condition when returning an error code
-from a library function.)
+Option B.	Change rvalue reference back to (non-const)
+lvalue-reference overload in each case
 
    
 
    
-It is important that this error_code/error_condition usage is done
-correctly for the thread library since it is likely to set the
-pattern for future TR libraries that interact with the operating
-system.
+Option C.	Add an additional (non-const) lvalue-reference
+overload in just the std::list cases
 
    
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-Move to Open, and recommend the issue be deferred until after the next
-Committee Draft is issued.
-
    
-
-
-
    Proposed resolution:
    
 
    
-Change 30.2.2 [thread.req.exception]/2:
+I think (B) would be very unfortunate, I really like the forward_list
+behaviour in (C) but feel (A) is needed for consistency.
 
    
-
-
    
 
    
--2- The error_category (19.5.1.1) of the error_code reported by
-such an exception's code() member function 
-is as specified in the error condition Clause.
-
-The error_code reported by such an exception's code() member
-function shall compare equal to one of the conditions specified in
-the function's error condition Clause. [Example: When the thread
-constructor fails:
-
+My actual preference would be NAD, ship with this as a breaking change as it
+is a more explicit interface.  I don't think that will fly though!
 
    
-
    
-ec.category() == implementation-defined // probably system_category
-ec == errc::resource_unavailable_try_again // holds true
-
    
-
-
    
-— end example]
-
    
-
-
    
-
-
-
-
 
-
-
    
-
    1109. std::includes should require CopyConstructible predicate
    
-
    Section: 25.5.5.1 [includes] Status: Tentatively NAD Editorial
- Submitter: Alisdair Meredith Opened: 2009-04-28  Last modified: 2009-05-23
    
-
    View other active issues in [includes].
    
-
    View all other issues in [includes].
    
-
    View all issues with Tentatively NAD Editorial status.
    
-
    Discussion:
    
 
    
-All the set operation algorithms require a CopyConstructible predicate, with
-the exception of std::includes.  This looks like a typo as much as anything,
-given the general library requirement that predicates are copy
-constructible, and wording style of other set-like operations.
+See the thread starting with c++std-lib-23725 for more discussion.
 
    
 
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-We agree with the proposed resolution.
-Move to NAD Editorial.
-
    
-
 
 
    Proposed resolution:
    
-
    
-Change 25.2 [algorithms.syn] and 25.5.5.1 [includes]:
-
    
-
-
    template<InputIterator Iter1, InputIterator Iter2,
-         typename CopyConstructible Compare>
-  requires Predicate<Compare, Iter1::value_type, Iter2::value_type>
-        && Predicate<Compare, Iter2::value_type, Iter1::value_type>
-  bool includes(Iter1 first1, Iter1 last1,
-                Iter2 first2, Iter2 last2,
-                Compare comp);
-
    
 
 
 
 
 
 
    
-
    1110. Is for_each overconstrained?
    
-
    Section: 25.3.4 [alg.foreach] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-04-29  Last modified: 2009-05-23
    
-
    View other active issues in [alg.foreach].
    
-
    View all other issues in [alg.foreach].
    
-
    View all issues with Open status.
    
+
    1134. Redundant specification of stdint.h, fenv.h, tgmath.h, and maybe complex.h
    
+
    Section: 18.4.2 [stdinth], 26.3.2 [fenv], 26.8 [c.math], 26.4.11 [cmplxh] Status: New
+ Submitter: Robert Klarer Opened: 2009-05-26  Last modified: 2009-06-14
    
+
    View all issues with New status.
    
 
    Discussion:
    
 
    
-Quoting working paper for reference (25.3.4 [alg.foreach]):
+This is probably editorial.
+
    
+
    
+The following items should be removed from the draft, because they're
+redundant with Annex D, and they arguably make some *.h headers
+non-deprecated:
 
    
-
-
    
-
    template<InputIterator Iter, Callable<auto, Iter::reference> Function>
-  requires CopyConstructible<Function>
-  Function for_each(Iter first, Iter last, Function f);
-
    
-
    
 
    
-1 Effects: Applies f to the result of dereferencing every iterator in the
- range [first,last), starting from first and proceeding to last - 1.
+18.4.2 [stdinth] (regarding <stdint.h>) 
 
    
 
    
-2 Returns: f.
+26.3.2 [fenv] (regarding <fenv.h>
 
    
 
    
-3 Complexity: Applies f exactly last - first times.
+Line 3 of 26.8 [c.math] (regarding <tgmath.h>) 
 
    
-
    
-
    
-
 
    
-P2 implies the passed object f should be invoked at each stage, rather than
-some copy of f.  This is important if the return value is to usefully
-accumulate changes.  So the requirements are an object of type Function can
-be passed-by-value, invoked multiple times, and then return by value.  In
-this case, MoveConstructible is sufficient. This would open support for
-move-only functors, which might become important in concurrent code as you
-can assume there are no other references (copies) of a move-only type and so
-freely use them concurrently without additional locks.
+26.4.11 [cmplxh] (regarding <complex.h>, though the note in this subclause is not redundant) 
 
    
 
 
    [
-See further discussion starting with c++std-lib-23686.
+2009-06-10 Ganesh adds:
 ]
    
 
 
-
    [
-Batavia (2009-05):
-]
    
-
 
    
-
    
-Pete suggests we may want to look at this in a broader context
-involving other algorithms.
-We should also consider the implications of parallelism.
-
    
-
    
-Move to Open, and recommend the issue be deferred until after the next
-Committee Draft is issued.
-
    
+While searching for stdint in the CD, I found that <stdint.h> is also
+mentioned in 3.9.1 [basic.fundamental] /5. It guess it should refer to
+<cstdint> instead.
 
    
 
 
 
    Proposed resolution:
    
 
    
-Change 25.2 [algorithms.syn] and 25.3.4 [alg.foreach]:
+Remove the section 18.4.2 [stdinth].
+
    
+
    
+Remove the section 26.3.2 [fenv].
+
    
+
    
+Remove 26.8 [c.math], p3:
 
    
 
-
    template<InputIterator Iter, Callable<auto, Iter::reference> Function>
-  requires CopyConstructible MoveConstructible<Function>
-  Function for_each(Iter first, Iter last, Function f);
-
    
+
    
+-3- The header <tgmath.h> effectively includes the headers <complex.h>
+and <math.h>.
+
    
+
    
+Remove the section 26.4.11 [cmplxh].
+
    
 
 
 
 
 
 
    
-
    1111. associative containers underconstrained
    
-
    Section: 23.4 [associative] Status: Review
- Submitter: Alisdair Meredith Opened: 2009-04-29  Last modified: 2009-05-23
    
-
    View other active issues in [associative].
    
-
    View all other issues in [associative].
    
-
    View all issues with Review status.
    
+
    1135. exception_ptr should support contextual conversion to bool
    
+
    Section: 18.8.5 [propagation] Status: New
+ Submitter: Daniel Krügler Opened: 2007-06-06  Last modified: 2009-06-09
    
+
    View other active issues in [propagation].
    
+
    View all other issues in [propagation].
    
+
    View all issues with New status.
    
 
    Discussion:
    
 
    
-According to table 87 (n2857) the expression X::key_equal for an unordered
-container shall return a value of type Pred, where Pred is an equivalence
-relation.
+As of
+N2857
+18.8.5 [propagation]/5, the implementation-defined type
+exception_ptr does provide the following ways to check whether
+it is a null value:
 
    
-
+
    void f(std::exception_ptr p) {
+  p == nullptr;
+  p == 0;
+  p == exception_ptr();
+}
+
    
 
    
-However, all 4 containers constrain Pred to be merely a Predicate,
-and not EquivalenceRelation.
+This is rather cumbersome way of checking for the null value
+and I suggest to require support for evaluation in a boolean
+context like so:
 
    
 
-
    [
-Batavia (2009-05):
-]
    
+
    void g(std::exception_ptr p) {
+  if (p) {}
+  !p;
+}
+
    
 
-
    
-
    
-We agree with the proposed resolution.
-
    
+
+
    Proposed resolution:
    
 
    
-Move to Review.
+In section 18.8.5 [propagation] insert a new paragraph between p.5 and p.6:
 
    
+
+
    
+
+An object e of type exception_ptr can be contextually converted to bool.
+The effect shall be as if e != exception_ptr() had been evaluated in place
+of e. There shall be no implicit conversion to arithmetic type, to
+enumeration type or to pointer type.
+
 
    
 
 
-
    Proposed resolution:
    
-
    
-For ordered containers, replace 
-
    
-
    Predicate<auto, Key, Key> Compare = less<Key>
-
    
-
    
-with 
-
    
-
    StrictWeakOrder<auto, Key, Key> Compare = less<Key>
-
    
 
+
+
+
    
+
    1136. Incomplete specification of nested_exception::rethrow_nested()
    
+
    Section: 18.8.6 [except.nested] Status: New
+ Submitter: Daniel Krügler Opened: 2007-06-06  Last modified: 2009-06-09
    
+
    View other active issues in [except.nested].
    
+
    View all other issues in [except.nested].
    
+
    View all issues with New status.
    
+
    Discussion:
    
 
    
-For unordered containers, replace 
+It was recently mentioned in a newsgroup article
+http://groups.google.de/group/comp.std.c++/msg/f82022aff68edf3d
+that the specification of the member function rethrow_nested() of the
+class nested_exception is incomplete, specifically it remains unclear
+what happens, if member nested_ptr() returns a null value. In
+18.8.6 [except.nested] we find only the following paragraph related to that:
 
    
-
    Predicate<auto, Key, Key> Compare = less<Key>
-
    
+
    void rethrow_nested() const; // [[noreturn]]
+
    
+
    
+-4- Throws: the stored exception captured by this nested_exception object.
+
    
+
    
 
    
-with 
+This is a problem, because it is possible to create an object of
+nested_exception with exactly such a state, e.g.
 
    
-
    EquivalenceRelation<auto, Key, Key> Compare = less<Key>
+
    #include <exception>
+#include <iostream>
+
+int main() try {
+  std::nested_exception e; // OK, calls current_exception() and stores it's null value
+  e.rethrow_nested(); // ?
+  std::cout << "A" << std::endl;
+}
+catch(...) {
+  std::cout << "B" << std::endl;
+}
 
    
 
    
-As in the following declarations:
+I suggest to follow the proposal of the reporter, namely to invoke
+terminate() if nested_ptr() return a null value of exception_ptr instead
+of relying on the fallback position of undefined behavior. This would
+be consistent to the behavior of a throw; statement when no
+exception is being handled.
 
    
 
-
    
+
+
    Proposed resolution:
    
 
    
-Associative containers 23.4 [associative]
+Change around 18.8.6 [except.nested]/4 as indicated:
 
    
+
    
 
    
- 1 Headers <map> and <set>:
+-4- Throws: the stored exception captured by this nested_exception
+object, if nested_ptr() != nullptr
 
    
 
    
-   Header <map> synopsis
+- Remarks: If nested_ptr() == nullptr, terminate()
+shall be called.
 
    
-
       namespace std {
-     template <ValueType Key, ValueType T,
-               PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
-               Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
-       requires NothrowDestructible<Key> && NothrowDestructible<T>
-             && CopyConstructible<Compare>
-             && AllocatableElement<Alloc, Compare, const Compare&>
-             && AllocatableElement<Alloc, Compare, Compare&&>
-     class map;
+
    
 
-     ...
 
-     template <ValueType Key, ValueType T,
-               PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
-               Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
-       requires NothrowDestructible<Key> && NothrowDestructible<T>
-             && CopyConstructible<Compare>
-             && AllocatableElement<Alloc, Compare, const Compare&>
-             && AllocatableElement<Alloc, Compare, Compare&&>
-     class multimap;
 
-     ...
 
-   }
-
    
 
+
    
+
    1137. Return type of conj and proj
    
+
    Section: 26.4.9 [cmplx.over] Status: New
+ Submitter: Marc Steinbach Opened: 2009-06-11  Last modified: 2009-06-27
    
+
    View all other issues in [cmplx.over].
    
+
    View all issues with New status.
    
+
    Discussion:
    
 
    
-   Header <set> synopsis
+In clause 1, the Working Draft 
+(N2857)
+specifies overloads of the
+functions
 
    
-
       namespace std {
-     template <ValueType Key, PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
-               Allocator Alloc = allocator<Key> >
-       requires NothrowDestructible<Key> && CopyConstructible<Compare>
-             && AllocatableElement<Alloc, Compare, const Compare&>
-             && AllocatableElement<Alloc, Compare, Compare&&>
-     class set;
-
-     ...
-
-     template <ValueType Key, PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
-               Allocator Alloc = allocator<Key> >
-       requires NothrowDestructible<Key> && CopyConstructible<Compare>
-             && AllocatableElement<Alloc, Compare, const Compare&>
-             && AllocatableElement<Alloc, Compare, Compare&&>
-     class multiset;
-
-     ...
-
-   }
+
    arg, conj, imag, norm, proj, real
 
    
-
 
    
- 23.4.1p2 Class template map [map]
+for non-complex arithmetic types (float, double,
+long double, and integers).
+The only requirement (clause 2) specifies effective type promotion of arguments.
 
    
-
     namespace std {
-   template <ValueType Key, ValueType T,
-             PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
-             Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
-     requires NothrowDestructible<Key> && NothrowDestructible<T>
-           && CopyConstructible<Compare>
-           && AllocatableElement<Alloc, Compare, const Compare&>
-           && AllocatableElement<Alloc, Compare, Compare&&>
-   class map {
-     ...
-   };
- }
-
    
-
-
 
    
- 23.4.2p2 Class template multimap [multimap]
+I strongly suggest to add the following requirement on the return types:
 
    
-
     namespace std {
-   template <ValueType Key, ValueType T,
-             PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
-             Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
-     requires NothrowDestructible<Key> && NothrowDestructible<T>
-           && CopyConstructible<Compare>
-           && AllocatableElement<Alloc, Compare, const Compare&>
-           && AllocatableElement<Alloc, Compare, Compare&&>
-   class multimap {
-     ...
-   };
- }
-
    
-
+
    
+All the specified overloads must return real (i.e., non-complex) values,
+specifically, the nested value_type of effectively promoted arguments.
+
    
 
 
    
- 23.4.3p2 Class template set [set]
+(This has no effect on arg, imag, norm, real:
+they are real-valued anyway.)
 
    
-
     namespace std {
-   template <ValueType Key, PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
-             Allocator Alloc = allocator<Key> >
-     requires NothrowDestructible<Key> && CopyConstructible<Compare>
-           && AllocatableElement<Alloc, Compare, const Compare&>
-           && AllocatableElement<Alloc, Compare, Compare&&>
-   class set {
-     ...
-   };
- }
-
    
-
-
+
    Rationale:
    
 
    
- 23.4.4p2 Class template multiset [multiset]
+Mathematically, conj() and proj(), like the transcendental functions, are
+complex-valued in general but map the (extended) real line to itself.
+In fact, both functions act as identity on the reals.
+A typical user will expect conj() and proj() to preserve this essential
+mathematical property in the same way as exp(), sin(), etc.
+A typical use of conj(), e.g., is the generic scalar product of n-vectors:
 
    
-
     namespace std {
-   template <ValueType Key, PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
-             Allocator Alloc = allocator<Key> >
-     requires NothrowDestructible<Key> && CopyConstructible<Compare>
-           && AllocatableElement<Alloc, Compare, const Compare&>
-           && AllocatableElement<Alloc, Compare, Compare&&>
-   class multiset {
-     ...
-   };
- }
-
    
 
+
    template<typename T>
+inline T
+scalar_product(size_t n, T const* x, T const* y) {
+  T result = 0;
+  for (size_t i = 0; i < n; ++i)
+    result += x[i] * std::conj(y[i]);
+  return result;
+}
+
    
 
    
- 23.5 Unordered associative containers [unord]
+This will work equally well for real and complex floating-point types T if
+conj() returns T. It will not work with real types if conj()
+returns complex values.
 
    
 
    
- 1 Headers <unordered_map> and <unordered_set>:
+Instead, the implementation of scalar_product becomes either less efficient
+and less useful (if a complex result is always returned), or unnecessarily
+complicated (if overloaded versions with proper return types are defined).
+In the second case, the real-argument overload of conj() cannot be used.
+In fact, it must be avoided.
 
    
 
    
- Header <unordered_map> synopsis
+Overloaded conj() and proj() are principally needed in generic programming.
+All such use cases will benefit from the proposed return type requirement,
+in a similar way as the scalar_product example.
+The requirement will not harm use cases where a complex return value
+is expected, because of implicit conversion to complex.
+Without the proposed return type guarantee, I find overloaded versions
+of conj() and proj() not only useless but actually troublesome.
 
    
-
     namespace std {
-   // 23.5.1, class template unordered_map:
-   template <ValueType Key,
-             ValueType T,
-             Callable<auto, const Key&> Hash = hash<Key>,
-             PredicateEquivalenceRelation<auto, Key, Key> Pred = equal_to<Key>,
-             Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
-     requires NothrowDestructible<Key> && NothrowDestructible<T>
-           && SameType<Hash::result_type, size_t>
-           && CopyConstructible<Hash> && CopyConstructible<Pred>
-           && AllocatableElement<Alloc, Pred, const Pred&>
-           && AllocatableElement<Alloc, Pred, Pred&&>
-           && AllocatableElement<Alloc, Hash, const Hash&>
-           && AllocatableElement<Alloc, Hash, Hash&&>
-     class unordered_map;
-
-   // 23.5.2, class template unordered_multimap:
-   template <ValueType Key,
-             ValueType T,
-             Callable<auto, const Key&> Hash = hash<Key>,
-             PredicateEquivalenceRelation<auto, Key, Key> Pred = equal_to<Key>,
-             Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
-     requires NothrowDestructible<Key> && NothrowDestructible<T>
-           && SameType<Hash::result_type, size_t>
-           && CopyConstructible<Hash> && CopyConstructible<Pred>
-           && AllocatableElement<Alloc, Pred, const Pred&>
-           && AllocatableElement<Alloc, Pred, Pred&&>
-           && AllocatableElement<Alloc, Hash, const Hash&>
-           && AllocatableElement<Alloc, Hash, Hash&&>
-     class unordered_multimap;
-
-   ...
- }
-
    
 
-
    
- Header <unordered_set> synopsis
-
    
-
     namespace std {
-   // 23.5.3, class template unordered_set:
-   template <ValueType Value,
-             Callable<auto, const Value&> Hash = hash<Value>,
-             PredicateEquivalenceRelation<auto, Value, Value> class Pred = equal_to<Value>,
-             Allocator Alloc = allocator<Value> >
-     requires NothrowDestructible<Value>
-           && SameType<Hash::result_type, size_t>
-           && CopyConstructible<Hash> && CopyConstructible<Pred>
-           && AllocatableElement<Alloc, Pred, const Pred&>
-           && AllocatableElement<Alloc, Pred, Pred&&>
-           && AllocatableElement<Alloc, Hash, const Hash&>
-           && AllocatableElement<Alloc, Hash, Hash&&>
-     class unordered_set;
-
-   // 23.5.4, class template unordered_multiset:
-   template <ValueType Value,
-             Callable<auto, const Value&> Hash = hash<Value>,
-             PredicateEquivalenceRelation<auto, Value, Value> class Pred = equal_to<Value>,
-             Allocator Alloc = allocator<Value> >
-     requires NothrowDestructible<Value>
-           && SameType<Hash::result_type, size_t>
-           && CopyConstructible<Hash> && CopyConstructible<Pred>
-           && AllocatableElement<Alloc, Pred, const Pred&>
-           && AllocatableElement<Alloc, Pred, Pred&&>
-           && AllocatableElement<Alloc, Hash, const Hash&>
-           && AllocatableElement<Alloc, Hash, Hash&&>
-     class unordered_multiset;
-
-   ...
- }
-
    
-
-
    
- 23.5.1p3 Class template unordered_map [unord.map]
-
    
-
     namespace std {
-   template <ValueType Key,
-             ValueType T,
-             Callable<auto, const Key&> Hash = hash<Key>,
-             PredicateEquivalenceRelation<auto, Key, Key> Pred = equal_to<Key>,
-             Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
-     requires NothrowDestructible<Key> && NothrowDestructible<T>
-           && SameType<Hash::result_type, size_t>
-           && CopyConstructible<Hash> && CopyConstructible<Pred>
-           && AllocatableElement<Alloc, Pred, const Pred&>
-           && AllocatableElement<Alloc, Pred, Pred&&>
-           && AllocatableElement<Alloc, Hash, const Hash&>
-           && AllocatableElement<Alloc, Hash, Hash&&>
-   class unordered_map
-   {
-     ...
-   };
- }
-
    
 
-
    
- 23.5.2p3 Class template unordered_multimap [unord.multimap]
-
    
-
     namespace std {
-   template <ValueType Key,
-             ValueType T,
-             Callable<auto, const Key&> Hash = hash<Key>,
-             PredicateEquivalenceRelation<auto, Key, Key> Pred = equal_to<Key>,
-             Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
-     requires NothrowDestructible<Key> && NothrowDestructible<T>
-           && SameType<Hash::result_type, size_t>
-           && CopyConstructible<Hash> && CopyConstructible<Pred>
-           && AllocatableElement<Alloc, Pred, const Pred&>
-           && AllocatableElement<Alloc, Pred, Pred&&>
-           && AllocatableElement<Alloc, Hash, const Hash&>
-           && AllocatableElement<Alloc, Hash, Hash&&>
-   class unordered_multimap
-   {
-     ...
-   };
- }
-
    
 
+
    Proposed resolution:
    
 
    
- 23.5.3p3 Class template unordered_set [unord.set]
-
    
-
     namespace std {
-   template <ValueType Value,
-             Callable<auto, const Value&> Hash = hash<Value>,
-             PredicateEquivalenceRelation<auto, Value, Value> class Pred = equal_to<Value>,
-             Allocator Alloc = allocator<Value> >
-     requires NothrowDestructible<Value>
-           && SameType<Hash::result_type, size_t>
-           && CopyConstructible<Hash> && CopyConstructible<Pred>
-           && AllocatableElement<Alloc, Pred, const Pred&>
-           && AllocatableElement<Alloc, Pred, Pred&&>
-           && AllocatableElement<Alloc, Hash, const Hash&>
-           && AllocatableElement<Alloc, Hash, Hash&&>
-   class unordered_set
-   {
-     ...
-   };
- }
-
    
-
    
- 23.5.4p3 Class template unordered_multiset [unord.multiset]
-
    
-
     namespace std {
-   template <ValueType Value,
-             Callable<auto, const Value&> Hash = hash<Value>,
-             PredicateEquivalenceRelation<auto, Value, Value> class Pred = equal_to<Value>,
-             Allocator Alloc = allocator<Value> >
-     requires NothrowDestructible<Value>
-           && SameType<Hash::result_type, size_t>
-           && CopyConstructible<Hash> && CopyConstructible<Pred>
-           && AllocatableElement<Alloc, Pred, const Pred&>
-           && AllocatableElement<Alloc, Pred, Pred&&>
-           && AllocatableElement<Alloc, Hash, const Hash&>
-           && AllocatableElement<Alloc, Hash, Hash&&>
-   class unordered_multiset
-   {
-     ...
-   };
- }
-
    
+Insert a new paragraph after 26.4.9 [cmplx.over]/2:
+
    
 
+
    
+
+All of the specified overloads shall have a return type which is the nested value_type of
+the effectively promoted arguments.
+
 
    
 
 
 
 
 
-
 
    
-
    1112. bitsets and new style for loop
    
-
    Section: 20.3.6 [template.bitset] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-05-06  Last modified: 2009-05-25
    
-
    View other active issues in [template.bitset].
    
-
    View all other issues in [template.bitset].
    
-
    View all issues with Open status.
    
+
    1138. unusal return value for operator+
    
+
    Section: 21.4.8.1 [string::op+] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-06-12  Last modified: 2009-06-15
    
+
    View all issues with New status.
    
 
    Discussion:
    
 
    
-Std::bitset is a homogeneous container-like sequence of bits, yet it does
-not model the Range concept so cannot be used with the new for-loop syntax.
-It is the only such type in the library that does NOT support the new for
-loop.
-
    
-
    
-The obvious reason is that bitset does not support iterators.
-
    
-
    
-At least two reasonable solutions are available:
-
    
-
      
-
    1. 
-Add an iterator interface to bitset, bringing its interface close to that
-of std::array
-
      2. 
-
    2. 
-Provide an unspecified concept_map for Range<bitset>.
-
      3. 
-
    
-
    
-The latter will still need some kind of iterator-like adapter for bitset,
-but gives implementers greater freedom on the details. E.g. begin/end return
-some type that simply invokes operator[] on the object it wraps, and
-increments its index on operator++.  A vendor can settle for InputIterator
-support, rather than wrapping up a full RandomAccessIterator.
-
    
-
    
-I have a mild preference for option (ii) as I think it is less work to
-specify at this stage of the process, although (i) is probably more useful
-in the long run.
+Many of the basic_string operator+ overloads return an rvalue-reference.  Is
+that really intended?
 
    
 
    
-Hmm, my wording looks a little woolly, as it does not say what the element
-type of the range is.  Do I get a range of bool, bitset<N>::reference, or
-something else entirely?
+I'm considering it might be a mild performance tweak to avoid making
+un-necessary copies of a cheaply movable type, but it opens risk to dangling
+references in code like:
 
    
+
+
    auto && s = string{"x"} + string{y};
+
    
+
 
    
-I guess most users will assume the behaviour of reference, but expect to
-work with bool.  Bool is OK for read-only traversal, but you really need to
-take a reference to a bitset::reference if you want to write back.
+and I'm not sure about:
 
    
 
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-Move to Open.
-We further recommend this be deferred until after the next Committee Draft.
-
    
+
    auto s = string{"x"} + string{y};
+
    
 
-
    [
-2009-05-25 Alisdair adds:
-]
    
 
+
    Proposed resolution:
    
+
    
+Strike the && from the return type in the following function
+signatures:
+
    
 
 
    
 
    
-I just stumbled over the Range concept_map for valarray and this should
-probably set the precedent on how to write the wording.
+21.3 [string.classes] p2 Header Synopsis
 
    
 
-
    [
-Howard: I've replaced the proposed wording with Alisdair's suggestion.
-]
    
+
    template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(basic_string<charT,traits,Allocator>&& lhs,
+              const basic_string<charT,traits,Allocator>& rhs);
+
+template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(const basic_string<charT,traits,Allocator>& lhs,
+              basic_string<charT,traits,Allocator>&& rhs);
 
+template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(basic_string<charT,traits,Allocator>&& lhs,
+              basic_string<charT,traits,Allocator>&& rhs);
 
-
    
 
+template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(const charT* lhs,
+              basic_string<charT,traits,Allocator>&& rhs);
 
+template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(charT lhs, basic_string<charT,traits,Allocator>&& rhs);
 
-
    Proposed resolution:
    
+template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(basic_string<charT,traits,Allocator>&& lhs,
+              const charT* rhs);
 
-
    
-20.3.6.X bitset concept maps [bitset.concepts] (made up clause name/number)
-
    
-
    template<size_t N>
-concept_map Range<bitset<N>> {
-  typedef unspecified iterator;
-  iterator begin(bitset<N>& a);
-  iterator end(bitset<N>& a);
-}
+template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(basic_string<charT,traits,Allocator>&& lhs, charT rhs);
+
    
 
-template<typename T>
-concept_map Range<const bitset<N>> {
-  typedef unspecified iterator;
-  iterator begin(const bitset<N>& a);
-  iterator end(const bitset<N>& a);
-}
-
    
 
    
--1- Note: these concept_maps adapt bitset to the Range concept.
+21.4.8.1 [string::op+]
 
    
 
-
    typedef unspecified iterator;
-
    
-
-
    
--2- Requires: iterator shall meet the requirements of the
-RandomAccessIterator concept and iterator::reference
-shall equal bitset<N>::reference or const bitset<N>::reference.
-
    
+
    template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(basic_string<charT,traits,Allocator>&& lhs,
+              const basic_string<charT,traits,Allocator>& rhs);
 
-
    iterator begin(bitset<N>& a);
-iterator begin(const bitset<N>& a);
-
    
+template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(const basic_string<charT,traits,Allocator>& lhs,
+              basic_string<charT,traits,Allocator>&& rhs);
 
-
    
--3- Returns: an iterator referencing the first bit in the bitset.
-
    
+template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(basic_string<charT,traits,Allocator>&& lhs,
+              basic_string<charT,traits,Allocator>&& rhs);
 
-
    iterator end(bitset<N>& a);
-iterator end(const bitset<N>& a);
-
    
 
-
    
--4- Returns: an iterator referencing one past the last bit in the bitset.
-
    
+template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(const charT* lhs,
+              basic_string<charT,traits,Allocator>&& rhs);
 
+template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(charT lhs, basic_string<charT,traits,Allocator>&& rhs);
 
+template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(basic_string<charT,traits,Allocator>&& lhs,
+              const charT* rhs);
 
+template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator>&&
+    operator+(basic_string<charT,traits,Allocator>&& lhs, charT rhs);
+
    
 
+
    
 
 
 
@@ -35652,521 +29423,541 @@ iterator end(const bitset<N>& a);
 
 
 
    
-
    1113. bitset::to_string could be simplified
    
-
    Section: 20.3.6 [template.bitset] Status: Open
- Submitter: Alisdair Meredith Opened: 2009-05-09  Last modified: 2009-05-23
    
-
    View other active issues in [template.bitset].
    
-
    View all other issues in [template.bitset].
    
-
    View all issues with Open status.
    
+
    1144. "thread safe" is undefined
    
+
    Section: 18.5 [support.start.term] Status: New
+ Submitter: LWG Opened: 2009-06-16  Last modified: 2009-07-04
    
+
    View all other issues in [support.start.term].
    
+
    View all issues with New status.
    
 
    Discussion:
    
-
    
-In 853 our resolution is changing the signature by adding two
-defaulting arguments to 3 calls.  In principle, this means that ABI breakage
-is not an issue, while API is preserved.
-
    
-
    
-With that observation, it would be very nice to use the new ability to
-supply default template parameters to function templates to collapse all 3
-signatures into 1.  In that spirit, this issue offers an alternative resolution
-than that of 853.
-
    
-
-
    [
-Batavia (2009-05):
-]
    
-
-
    
-Move to Open,
-and look at the issue again after 853 has been accepted.
-We further recommend this be deferred until after the next Committee Draft.
-
    
 
+
    Addresses UK 187
    
 
-
    Proposed resolution:
    
-
-
      
-
    1. 
 
      
-In 20.3.6 [template.bitset]/1 (class bitset) ammend:
+The term "thread safe" is not defined nor used in this context
+anywhere else in the standard.
 
      
-
      template <class charT = char,
-            class traits = char_traits<charT>,
-            class Allocator = allocator<charT>> 
-  basic_string<charT, traits, Allocator>
-  to_string(charT zero = charT('0'), charT one = charT('1')) const;
-template <class charT, class traits> 
-  basic_string<charT, traits, allocator<charT> > to_string() const; 
-template <class charT> 
-  basic_string<charT, char_traits<charT>, allocator<charT> > to_string() const; 
-basic_string<char, char_traits<char>, allocator<char> > to_string() const;
-
      
-
      2. 
-
    2. 
+
+
      Suggested action:
      
 
      
-In 20.3.6.2 [bitset.members] prior to p35 ammend:
+Clarify the meaning of "thread safe".
 
      
-
      template <class charT = char,
-            class traits = char_traits<charT>,
-            class Allocator = allocator<charT>> 
-  basic_string<charT, traits, Allocator>
-  to_string(charT zero = charT('0'), charT one = charT('1')) const;
-
      
-
      3. 
-
    3. 
-Strike 20.3.6.2 [bitset.members] paragraphs 37 -> 39 (including signature
-above 37)
-
      4. 
-
    
 
 
+
    Proposed resolution:
    
+
 
 
 
 
 
    
-
    1114. Type traits underspecified
    
-
    Section: 20.6 [meta] Status: Open
- Submitter: Daniel Krügler Opened: 2009-05-12  Last modified: 2009-05-23
    
-
    View other active issues in [meta].
    
-
    View all other issues in [meta].
    
-
    View all issues with Open status.
    
+
    1145. inappropriate headers for atomics
    
+
    Section: 29 [atomics] Status: New
+ Submitter: LWG Opened: 2009-06-16  Last modified: 2009-07-04
    
+
    View other active issues in [atomics].
    
+
    View all other issues in [atomics].
    
+
    View all issues with New status.
    
 
    Discussion:
    
 
+
    Addresses UK 312
    
+
 
    
-Related to 975 and 1023.
+The contents of the <stdatomic.h> header are not listed anywhere,
+and <cstdatomic> is listed as a C99 header in chapter 17.
+If we intend to use these for compatibility with a future C standard,
+we should not use them now.
 
    
 
+
+
    Proposed resolution:
    
 
    
-The current wording in 20.6.1 [meta.rqmts] is still unclear concerning
-it's requirements on the type traits classes regarding ambiguities.
-Specifically it's unclear
+Remove <cstdatomic> from the C99 headers in table 14.
+Add a new header <atomic> to the headers in table 13.
+Update chapter 29 to remove reference to <stdatomic.h>
+and replace the use of <cstdatomic> with <atomic>.
 
    
+
    [
+If and when WG14 adds atomic operations to C
+we can add corresponding headers to table 14 with a TR.
+]
    
+
+
+
 
-
      
-
    • 
-if a predicate trait (20.6.4 [meta.unary], 20.6.5 [meta.rel]) could derive from both
-true_type/false_type.
-
      • 
-
    • 
-if any of the type traits (20.6.1 [meta.rqmts], 20.6.4 [meta.unary], 20.6.5 [meta.rel]) could ambiguously derive
-from the same specified result type.
-
      • 
-
    • 
-if any of the type traits (20.6.1 [meta.rqmts], 20.6.4 [meta.unary], 20.6.5 [meta.rel]) could derive from other
-integral_constant types making the contained names ambiguous
-
      • 
-
    • 
-if any of the type traits (20.6.1 [meta.rqmts], 20.6.4 [meta.unary], 20.6.5 [meta.rel]) could have other base
-classes that contain members hiding the name of the result type members
-or make the contained member names ambiguous.
-
      • 
-
    
+
+
+
    
+
    1146. "lockfree" does not say enough
    
+
    Section: 29.4 [atomics.lockfree] Status: New
+ Submitter: Jeffrey Yasskin Opened: 2009-06-16  Last modified: 2009-07-04
    
+
    View all issues with New status.
    
+
    Discussion:
    
+
+
    Addresses US 88
    
+
+
    
+The "lockfree" facilities do not tell the programmer enough.
+
    
+
+
    
+There are 2 problems here.
+First, at least on x86,
+it's less important to me whether some integral types are lock free
+than what is the largest type I can pass to atomic and have it be lock-free.
+For example, if long longs are not lock-free,
+ATOMIC_INTEGRAL_LOCK_FREE is probably 1,
+but I'd still be interested in knowing whether longs are always lock-free.
+Or if long longs at any address are lock-free,
+I'd expect ATOMIC_INTEGRAL_LOCK_FREE to be 2,
+but I may actually care whether I have access to
+the cmpxchg16b instruction.
+None of the support here helps with that question.
+(There are really 2 related questions here:
+what alignment requirements are there for lock-free access;
+and what processor is the program actually running on,
+as opposed to what it was compiled for?)
+
    
+
+
    
+Second, having atomic_is_lock_free only apply to individual objects
+is pretty useless
+(except, as Lawrence Crowl points out,
+for throwing an exception when an object is unexpectedly not lock-free).
+I'm likely to want to use its result to decide what algorithm to use,
+and that algorithm is probably going to allocate new memory
+containing atomic objects and then try to act on them.
+If I can't predict the lock-freedom of the new object
+by checking the lock-freedom of an existing object,
+I may discover after starting the algorithm that I can't continue.
+
    
 
 
    [
-Batavia (2009-05):
+2009-06-16 Jeffrey Yasskin adds:
 ]
    
 
+
 
    
 
    
-Alisdair would prefer to factor some of the repeated text,
-but modulo a corner case or two,
-he believes the proposed wording is otherwise substantially correct.
+To solve the first problem, I think 2 macros would help:
+MAX_POSSIBLE_LOCK_FREE_SIZE and MAX_GUARANTEED_LOCK_FREE_SIZE,
+which expand to the maximum value of sizeof(T) for which atomic may
+(or will, respectively) use lock-free operations.
+Lawrence points out that this
+"relies heavily on implementations
+using word-size compare-swap on sub-word-size types,
+which in turn requires address modulation."
+He expects that to be the end state anyway, so it doesn't bother him much.
 
    
+
 
    
-Move to Open.
+To solve the second,
+I think one could specify that equally aligned objects of the same type
+will return the same value from atomic_is_lock_free().
+I don't know how to specify "equal alignment".
+Lawrence suggests an additional function, atomic_is_always_lock_free().
 
    
 
    
 
 
+
 
    Proposed resolution:
    
-
    [
-The usage of the notion of a BaseCharacteristic below
-might be
-useful in other places - e.g. to define the base class relation in
-20.7.5 [refwrap], 20.7.15 [func.memfn], or 20.7.16.2 [func.wrap.func].
-In this case it's definition should probably
-be moved to Clause 17
-]
    
 
 
-
      
-
    1. 
+
+
+
+
      
+
      1147. non-volatile atomic functions
      
+
      Section: 29.6 [atomics.types.operations] Status: New
+ Submitter: Jeffrey Yasskin Opened: 2009-06-16  Last modified: 2009-07-04
      
+
      View other active issues in [atomics.types.operations].
      
+
      View all other issues in [atomics.types.operations].
      
+
      View all issues with New status.
      
+
      Discussion:
      
+
+
      Addresses US 90
      
+
 
      
-Change 20.6.1 [meta.rqmts]/1 as indicated:
+The C++0X draft
+declares all of the functions dealing with atomics (section 29.6 [atomics.types.operations])
+to take volatile arguments.
+Yet it also says (29.4-3),
 
      
+
 
      
-[..] It shall be DefaultConstructible, CopyConstructible, and publicly
-and unambiguously derived, directly or indirectly, from
-its BaseCharacteristic, which is a specialization of the
-template integral_constant (20.6.3), with the arguments to the template
-integral_constant determined by the requirements for the particular
-property being described. The member names of the
-BaseCharacteristic shall be unhidden and unambiguously
-available in the UnaryTypeTrait.
-
      
-
      2. 
-
    2. 
 
      
-Change 20.6.1 [meta.rqmts]/2 as indicated:
+[ Note: Many operations are volatile-qualified.
+The "volatile as device register" semantics have not changed in the standard.
+This qualification means that volatility is preserved
+when applying these operations to volatile objects.
+It does not mean that operations on non-volatile objects become volatile.
+Thus, volatile qualified operations on non-volatile objects
+may be merged under some conditions. —end note ]
 
      
-
      
-[..] It shall be DefaultConstructible, CopyConstructible, and publicly
-and unambiguously derived, directly or indirectly, from
-an instance its BaseCharacteristic, which is a
-specialization of the template integral_constant (20.6.3), with
-the arguments to the template integral_constant determined by the
-requirements for the particular relationship being described. The
-member names of the BaseCharacteristic shall be unhidden
-and unambiguously available in the BinaryTypeTrait.
 
      
-
      3. 
-
    3. 
+
 
      
-Change 20.6.4 [meta.unary]/2 as indicated:
+I was thinking about how to implement this in gcc,
+and I believe that we'll want to overload most of the functions
+on volatile and non-volatile.
+Here's why:
 
      
-
      
-Each of these templates shall be a UnaryTypeTrait (20.6.1),
-publicly derived directly or indirectly from true_type if the
-corresponding condition is true, otherwise from false_type
-where its BaseCharacteristic shall be true_type if the
-corresponding condition is true, otherwise false_type.
-
      
-
      4. 
-
    4. 
+
 
      
-Change 20.6.5 [meta.rel]/2 as indicated:
+To let the compiler take advantage of the permission
+to merge non-volatile atomic operations and reorder atomics in certain,
+we'll need to tell the compiler backend
+about exactly which atomic operation was used.
+So I expect most of the functions of the form atomic_<op>_explicit()
+(e.g. atomic_load_explicit, atomic_exchange_explicit,
+atomic_fetch_add_explicit, etc.)
+to become compiler builtins.
+A builtin can tell whether its argument was volatile or not,
+so those functions don't really need extra explicit overloads.
+However, I don't expect that we'll want to add builtins
+for every function in chapter 29,
+since most can be implemented in terms of the _explicit free functions:
 
      
 
-
      
-Each of these templates shall be a BinaryTypeTrait (20.6.1),
-publicly derived directly or indirectly from true_type if the
-corresponding condition is true, otherwise from false_type
-where its BaseCharacteristic shall be true_type if the
-corresponding condition is true, otherwise false_type.
-
      
-
      5. 
-
    
+
    class atomic_int {
+  __atomic_int_storage value;
+ public:
+  int fetch_add(int increment, memory_order order = memory_order_seq_cst) volatile {
+    // &value has type "volatile __atomic_int_storage*".
+    atomic_fetch_add_explicit(&value, increment, order);
+  }
+  ...
+};
+
    
 
+
    
+But now this always calls
+the volatile builtin version of atomic_fetch_add_explicit(),
+even if the atomic_int wasn't declared volatile.
+To preserve volatility and the compiler's permission to optimize,
+I'd need to write:
+
    
 
+
    class atomic_int {
+  __atomic_int_storage value;
+ public:
+  int fetch_add(int increment, memory_order order = memory_order_seq_cst) volatile {
+    atomic_fetch_add_explicit(&value, increment, order);
+  }
+  int fetch_add(int increment, memory_order order = memory_order_seq_cst) {
+    atomic_fetch_add_explicit(&value, increment, order);
+  }
+  ...
+};
+
    
 
+
    
+But this is visibly different from the declarations in the standard
+because it's now overloaded.
+(Consider passing &atomic_int::fetch_add as a template parameter.)
+
    
 
+
    
+The implementation may already have permission to add overloads
+to the member functions:
+
    
 
+
    
+
    
+17.6.4.5 [member.functions] An implementation may declare additional non-virtual
+member function signatures within a class:
    
+...
+
    
+
      
+
    • by adding a member function signature for a member function name.
      • 
+
    
+
    
 
-
    
-
    1115. va_copy missing from Standard macros table
    
-
    Section: C.2 [diff.library] Status: New
- Submitter: Miles Zhao Opened: 2009-05-23  Last modified: 2009-05-23
    
-
    View all other issues in [diff.library].
    
-
    View all issues with New status.
    
-
    Discussion:
    
 
    
-In "Table 122 -- Standard macros" of C.2 [diff.library], which lists the 56 macros
-inherited from C library, va_copy seems to be missing. But in
-"Table 21 -- Header <cstdarg> synopsis" (18.10 [support.runtime]), there is.
+but I don't see an equivalent permission to add overloads to the free functions.
 
    
 
+
    [
+2009-06-16 Lawrence adds:
+]
    
+
 
-
    Proposed resolution:
    
+
    
 
    
-Add va_copy to Table 122 -- Standard macros in C.2 [diff.library].
+I recommend allowing non-volatile overloads.
 
    
+
    
+
+
+
+
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1116. Literal constructors for tuple
    
-
    Section: 20.5.2 [tuple.tuple] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-23  Last modified: 2009-05-24
    
-
    View other active issues in [tuple.tuple].
    
-
    View all other issues in [tuple.tuple].
    
+
    1148. Wrong argument type of I/O stream manipulators setprecision()
+and setw()
    
+
    Section: 27.7 [iostream.format] Status: New
+ Submitter: Marc Steinbach Opened: 2009-06-20  Last modified: 2009-07-30
    
+
    View all other issues in [iostream.format].
    
 
    View all issues with New status.
    
 
    Discussion:
    
 
    
-It is not currently possible to construct tuple literal values,
-even if the elements are all literal types.  This is because parameters
-are passed to constructor by reference.
+The header <iomanip> synopsis in 27.7 [iostream.format] specifies
 
    
+
    T5 setprecision(int n);
+T6 setw(int n);
+
    
+
 
    
-An alternative would be to pass all constructor arguments by value, where it
-is known that *all* elements are literal types.  This can be determined with
-concepts, although note that the negative constraint really requires
-factoring out a separate concept, as there is no way to provide an 'any of
-these fails' constraint inline.
+The argument types should be streamsize, as in class ios_base
+(see 27.5.2 [ios.base]):
 
    
+
    streamsize precision() const;
+streamsize precision(streamsize prec);
+streamsize width() const;
+streamsize width(streamsize wide);
+
    
+
 
    
-Note that we will have similar issues with pair (and
-tuple constructors from pair) although I am steering
-clear of that class while other constructor-related issues settle.
+(Editorial: 'wide' should probably be renamed as 'width', or maybe just 'w'.)
 
    
 
+
    [
+2009-07-29 Daniel clarified wording.
+]
    
 
-
    Proposed resolution:
    
-
    
-Ammend the tuple class template declaration in 20.5.2 [tuple.tuple] as
-follows
-
    
 
-
    
+
+
    Proposed resolution:
    
+
      
+
    1. 
 
      
-Add the following concept:
+In 27.7 [iostream.format], header <iomanip> synopsis change as indicated:
 
      
 
-
      auto concept AllLiteral< typename ... Types > {
-  requires LiteralType<Types>...;
-}
+
      T5 setprecision(intstreamsize n);
+T6 setw(intstreamsize n);
 
      
+
      2. 
 
+
    2. 
 
      
-ammend the constructor 
+In 27.7.3 [std.manip], just before p. 6 change as indicated:
 
      
 
-
      template <class... UTypes>
-  requires AllLiteral<Types...>
-        && Constructible<Types, UTypes>...
-  explicit tuple(UTypes...);
-
-template <class... UTypes>
-  requires !AllLiteral<Types...>
-        && Constructible<Types, UTypes&&>...
-  explicit tuple(UTypes&&...);
+
      unspecified setprecision(intstreamsize n);
 
      
+
      3. 
 
+
    3. 
 
      
-ammend the constructor
+In 27.7.3 [std.manip], just before p. 7 change as indicated:
 
      
 
-
      template <class... UTypes>
-  requires AllLiteral<Types...>
-        && Constructible<Types, UTypes>...
-  tuple(tuple<UTypes...>);
-
-template <class... UTypes>
-  requires !AllLiteral<Types...>
-        && Constructible<Types, const UTypes&>...
-  tuple(const tuple<UTypes...>&);
+
      unspecified setw(intstreamsize n);
 
      
+
      4. 
+
    
+
 
-
    
 
-
    
-Update the same signatures in 20.5.2.1 [tuple.cnstr], paras 3 and 5.
-
    
 
 
 
 
 
 
    
-
    1117. tuple copy constructor
    
-
    Section: 20.5.2.1 [tuple.cnstr] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-23  Last modified: 2009-05-30
    
-
    View other active issues in [tuple.cnstr].
    
-
    View all other issues in [tuple.cnstr].
    
+
    1150. wchar_t, char16_t and char32_t filenames
    
+
    Section: 27.9.1.14 [fstream] Status: New
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-04
    
 
    View all issues with New status.
    
 
    Discussion:
    
-
    
-The copy constructor for the tuple template is constrained.  This seems an
-unusual strategy, as the copy constructor will be implicitly deleted if the
-constraints are not met.  This is exactly the same effect as requesting an
-=default; constructor.  The advantage of the latter is that it retains
-triviality, and provides support for tuples as literal types if issue
-1116 is also accepted.
-
    
-
    
-Actually, it might be worth checking with core if a constrained copy
-constructor is treated as a constructor template, and as such does not
-suppress the implicit generation of the copy constructor which would hide
-the template in this case.
-
    
+
    Addresses JP 73
    
+
+   
    Description
    
+        
    It is a problem
+        from C++98, fstream cannot appoint a filename of wide
+        character string(const wchar_t and const wstring&).
    
+
    Suggestion
    
+        
    Add
+        interface corresponding to wchar_t, char16_t and char32_t.
    
 
 
    [
-2009-05-27 Daniel adds:
+2009-07-01 Alisdair notes that this is a duplicate of 454 which has more
+in-depth rationale.
 ]
    
 
 
-
    
-This would solve one half of the suggested changes in 801.
-
    
-
 
 
    Proposed resolution:
    
-
    
-Change 20.5.2 [tuple.tuple] and 20.5.2.1 [tuple.cnstr] p4:
-
    
-
-
    requires CopyConstructible<Types>... tuple(const tuple&) = default;
-
    
 
 
 
 
 
 
    
-
    1118. tuple query APIs do not support cv-qualification
    
-
    Section: 20.5.2.3 [tuple.helper] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-23  Last modified: 2009-05-25
    
-
    View other active issues in [tuple.helper].
    
-
    View all other issues in [tuple.helper].
    
+
    1151. Behavior of the library in the presence of threads is incompletely specified
    
+
    Section: 17 [library] Status: New
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-06-28
    
+
    View other active issues in [library].
    
+
    View all other issues in [library].
    
 
    View all issues with New status.
    
 
    Discussion:
    
-
    
-The APIs tuple_size and tuple_element do not support
-cv-qualified tuples, pairs or arrays.
-
    
-
    
-The most generic solution would be to supply partial specializations once
-for each cv-type in the tuple header.  However, requiring this header for
-cv-qualified pairs/arrays seems unhelpful.  The BSI editorial
-suggestion (UK-198/US-69,
-N2533)
-to merge tuple into <utility> would help with pair,
-but not array.  That might be resolved by making a dependency between the
-<array> header and <utility>, or simply recognising
-the dependency be fulfilled in a Remark.
+
    Addresses US 63
    
+
+   
    Description
    
+        
    The behavior of the library in the presence of threads
+        is incompletely specified.
    
+        
    For example, if thread 1 assigns to X, then writes data
+        to file f, which is read by thread 2, and then accesses
+        variable X, is thread 2 guaranteed to be able to see the
+        value assigned to X by thread 1? In other words, does the
+        write of the data "happen before" the read?
    
+        
    Another example: does simultaneous access using operator
+        at() to different characters in the same non-const string
+        really introduce a data race?
    
+
    Suggestion
    
+
    Notes
    17 SG: should go to threads group; misclassified in document
 
    
 
-
    [
-2009-05-24 Daniel adds:
-]
    
+    
    Concurrency SG: Create an issue. Hans will look into it.
    
+
+
+
    Proposed resolution:
    
+
 
 
-
    
-
    
-All tuple_size templates with a base class need to derive publicly, e.g.
-
    
 
-
    template <IdentityOf T> class tuple_size< const T > :
-   public tuple_size<T> {};
-
    
 
+
    
+
    1152. expressions parsed differently than intended
    
+
    Section: 22.4.2.2.2 [facet.num.put.virtuals] Status: New
+ Submitter: Seungbeom Kim Opened: 2009-06-27  Last modified: 2009-07-24
    
+
    View other active issues in [facet.num.put.virtuals].
    
+
    View all other issues in [facet.num.put.virtuals].
    
+
    View all issues with New status.
    
+
    Discussion:
    
 
    
-The same applies to the tuple_element class hierarchies.
-
    
-
    
-What is actually meant with the comment
-
    
-
    
-this solution relies on 'metafunction forwarding' to inherit the
-nested typename type
-
    
-
    
-?
-
    
-
    
-I ask, because all base classes are currently unconstrained and their
-instantiation is invalid in the constrained context of the tuple_element partial
-template specializations.
+In Table 73 -- Floating-point conversions, 22.4.2.2.2 [facet.num.put.virtuals], 
+in
+N2914,
+we have the following entries: 
 
    
-
    
-
-
    [
-2009-05-24 Alisdair adds:
-]
    
+
+
+
+
+
+
+
+
+
 
+
+
+
+
+
    Table 73 — Floating-point conversions
    State stdio equivalent
    floatfield == ios_base::fixed | ios_base::scientific && !uppercase%a
    floatfield == ios_base::fixed | ios_base::scientific%A
    
 
-
    
 
    
-I think a better solution might be to ask Pete editorially to change all
-declarations of tupling APIs to use the struct specifier instead of class.
+These expressions are supposed to mean: 
 
    
+
+
    floatfield == (ios_base::fixed | ios_base::scientific) && !uppercase 
+floatfield == (ios_base::fixed | ios_base::scientific) 
+
    
 
    
-"metafunction forwarding" refers to the MPL metafunction protocol, where a
-metafunction result is declared as a nested typedef with the name "type",
-allowing metafunctions to be chained by means of inheritance.  It is a
-neater syntax than repeatedly declaring a typedef, and inheritance syntax is
-slightly nicer when it comes to additional typename keywords.
+but technically parsed as: 
 
    
+
    ((floatfield == ios_base::fixed) | ios_base::scientific) && (!uppercase) 
+((floatfield == ios_base::fixed) | ios_base::scientific) 
+
    
 
    
-The constrained template with an unconstrained base is a good observation
-though.
+and should be corrected with additional parentheses, as shown above. 
 
    
-
    
-
 
 
 
    Proposed resolution:
    
 
    
-Add to 20.5.1 [tuple.general] p2 (Header <tuple> synopsis)
+Change Table 73 — Floating-point conversions in  22.4.2.2.2 [facet.num.put.virtuals]:
 
    
 
-
    // 20.5.2.3, tuple helper classes:
-template <IdentityOf T> class tuple_size; // undefined
-template <IdentityOf T> class tuple_size< const T > : tuple_size<T> {};
-template <IdentityOf T> class tuple_size< volatile T > : tuple_size<T> {};
-template <IdentityOf T> class tuple_size< const volatile T > : tuple_size<T> {};
+
+
+
+
+
+
+
+
+
 
-template <VariableType... Types> class tuple_size<tuple<Types...> >;
+
+
+
+
+
    Table 73 — Floating-point conversions
    State stdio equivalent
    floatfield == (ios_base::fixed | ios_base::scientific) && !uppercase%a
    floatfield == (ios_base::fixed | ios_base::scientific)%A
    
 
-template <size_t I, IdentityOf T> class tuple_element; // undefined
-template <size_t I, IdentityOf T> class tuple_element<I, const T>;
-template <size_t I, IdentityOf T> class tuple_element<I, volatile T>;
-template <size_t I, IdentityOf T> class tuple_element<I, const volatile T>;
 
-template <size_t I, VariableType... Types>
-  requires True<(I < sizeof...(Types))> class tuple_element<I, tuple<Types...> >;
-
    
 
-
    
-Add to 20.5.2.3 [tuple.helper]
-
    
-
    [
-(note that this solution relies on 'metafunction forwarding' to inherit the
-nested typename type)
-]
    
 
 
-
    template <class... Types>
-class tuple_size<tuple<Types...> >
-  : public integral_constant<size_t, sizeof...(Types)> { };
+
    
+
    1153. Standard library needs review for constructors to be
+explicit to avoid treatment as initializer-list constructor
    
+
    Section: 17 [library], 30 [thread], D [depr] Status: New
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-04
    
+
    View other active issues in [library].
    
+
    View all other issues in [library].
    
+
    View all issues with New status.
    
+
    Discussion:
    
 
-template <size_t I, class... Types>
-requires True<(I < sizeof...(Types))>
-class tuple_element<I, tuple<Types...> > {
-public:
-  typedef TI type;
-};
+
    Addresses DE 2
    
 
-template <size_t I, IdentityOf T>
-  class tuple_element<I, const T> : add_const<tuple_element<I,T>> {};
+
    Description
    
+        
    Marking a constructor with explicit has semantics
+        even for a constructor with zero or several parameters:
+        Such a constructor cannot be used with list-initialization
+        in a copy-initialization context, see 13.3.1.7 [over.match.list]. The
+        standard library apparently has not been reviewed for
+        marking non-single-parameter constructors as explicit.
    
+
    Suggestion
    
+        
    Consider marking zero-parameter and multi-parameter
+        constructors explicit in classes that have at least one
+        constructor marked explicit and that do not have an
+        initializer-list constructor.
    
 
-template <size_t I, IdentityOf T>
-  class tuple_element<I, volatile T> : add_volatile<tuple_element<I,T>> {};
+
    Notes
    
+        
    Robert Klarer to address this one.
    
 
-template <size_t I, IdentityOf T>
-  class tuple_element<I, const volatile T> : add_cv<tuple_element<I,T>> {};
-
    
+
+
+
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1119. tuple query APIs do not support references
    
-
    Section: 20.5.2.3 [tuple.helper] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-23  Last modified: 2009-05-24
    
-
    View other active issues in [tuple.helper].
    
-
    View all other issues in [tuple.helper].
    
+
    1154. complex should accept integral types
    
+
    Section: 26.4 [complex.numbers] Status: New
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-04
    
+
    View all other issues in [complex.numbers].
    
 
    View all issues with New status.
    
 
    Discussion:
    
-
    
-The tuple query APIs tuple_size and
-tuple_element do not support references-to-tuples.  This can be
-annoying when a template deduced a parameter type to be a reference,
-which must be explicitly stripped with remove_reference before calling
-these APIs.
-
    
-
    
-I am not proposing a resolution at this point, as there is a
-combinatorial explosion with lvalue/rvalue references and
-cv-qualification (see previous issue) that suggests some higher
-refactoring is in order.  This might be something to kick back over to
-Core/Evolution.
-
    
-
    
-Note that we have the same problem in numeric_limits.
-
    
+
+
    Addresses FR 35
    
+
+
    Description
    
+        
    Instantiations of the class
+        template complex<> have to be allowed for integral
+        types, to reflect existing practice and ISO standards
+        (LIA-III).
    
+        
+
    Suggestion
    
+
 
 
 
    Proposed resolution:
    
@@ -36176,30 +29967,32 @@ Note that we have the same problem in numeric_limits.
 
 
 
    
-
    1120. New type trait - remove_all
    
-
    Section: 20.6 [meta] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-23  Last modified: 2009-05-24
    
-
    View other active issues in [meta].
    
-
    View all other issues in [meta].
    
+
    1155. Reference should be to C99
    
+
    Section: C.2 [diff.library] Status: New
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-25
    
+
    View other active issues in [diff.library].
    
+
    View all other issues in [diff.library].
    
 
    View all issues with New status.
    
 
    Discussion:
    
-
    
-Sometimes it is necessary to remove all qualifiers from a type before
-passing on to a further API.  A good example would be calling the
-tuple query APIs tuple_size or tuple_element
-with a deduced type inside a function template.  If the deduced type is
-cv-qualified or a reference then the call will fail.  The solution is to
-chain calls to
-remove_cv<remove_reference<T>::type>::type, and
-note that the order matters.
-
    
-
    
-Suggest it would be helpful to add a new type trait,
-remove_all, that removes all top-level qualifiers from a type
-i.e. cv-qualification and any references.  Define the term in such a way
-that if additional qualifiers are added to the language, then
-remove_all is defined as stripping those as well.
-
    
+
+
    Addresses FR 38
    
+
+
    Description
    
+        
    What is ISO/IEC 1990:9899/DAM
+        1? My guess is that's a typo for ISO/IEC
+        9899/Amd.1:1995 which I'd
+        have expected to be referenced here (the tables
+        make reference to things
+        which were introduced by Amd.1).
    
+
    Suggestion
    
+        
    One need probably a reference
+        to the document which introduce char16_t and
+        char32_t in C (ISO/IEC TR 19769:2004?).
    
+
    Notes
    
+
    Create issue. Document in question should be C99, not C90+amendment1. The 
+    rest of the section requires careful review for completeness. Example <cstdint> 
+    18.4.1 [cstdint.syn]. Assign to C liasons.
    
+
 
 
 
    Proposed resolution:
    
@@ -36209,76 +30002,147 @@ that if additional qualifiers are added to the language, then
 
 
 
    
-
    1121. Support for multiple arguments
    
-
    Section: 20.4.2 [ratio.arithmetic] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-25  Last modified: 2009-05-25
    
-
    View other active issues in [ratio.arithmetic].
    
-
    View all other issues in [ratio.arithmetic].
    
+
    1156. Constraints on bitmask and enumeration types to be tightened
    
+
    Section: 17.5.2.1.2 [enumerated.types], 17.5.2.1.3 [bitmask.types] Status: New
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-25
    
 
    View all issues with New status.
    
 
    Discussion:
    
-
    
-Both add and multiply could sensibly be called with more than two arguments.
-The variadic template facility makes such declarations simple, and is likely
-to be frequently wrapped by end users if we do not supply the variant
-ourselves.
-
    
-
    
-We deliberately ignore divide at this point as it is not transitive.
-Likewise, subtract places special meaning on the first argument so I do not
-suggest extending that immediately.  Both could be supported with analogous
-wording to that for add/multiply below.
-
    
-
    
-Note that the proposed resolution is potentially incompatible with that
-proposed for 921, although the addition of the typedef to ratio would be
-equally useful.
-
    
+
+
    Addresses UK 165
    
+
+
    Description
    
+        
    Constraints on
+        bitmask and enumeration types were supposed to be tightened
+        up as part of the motivation for the constexpr feature -
+        see paper
+        N2235
+        for details
    
+
    Suggestion
    
+        
    Adopt wording in line with the motivation
+        described in
+        N2235
    
+
    Notes
    
+        
    Robert Klarer to review
    
+
 
 
 
    Proposed resolution:
    
+
+
+
+
+
+
    
+
    1157. Local types can now instantiate templates
    
+
    Section: 17.6.3.2.1 [namespace.std] Status: Review
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-28
    
+
    View all issues with Review status.
    
+
    Discussion:
    
+
+
    Addresses UK 175
    
+
+
    Description
    
+        
    Local types can
+        now be used to instantiate templates, but don't have
+        external linkage.
    
+
    Suggestion
    
+        
    Remove the reference to external linkage.
    
+
+
    Notes
    
+
    We accept the proposed solution. Martin will draft an issue.
    
+
 
    [
-note that this wording relies on 'metafunction forwarding' as described by
-Boost MPL
+2009-07-28 Alisdair provided wording.
 ]
    
 
 
+
+
+
    Proposed resolution:
    
 
    
-20.4 [ratio] p3 synopsis: change
+17.6.3.2.1 [namespace.std]
+
    
+
    
+Strike "of external linkage" in p1 and p2:
 
    
 
-
    // ratio arithmetic
-template <class R1, class R2, class ... RList> struct ratio_add;
-template <class R1, class R2> struct ratio_subtract;
-template <class R1, class R2, class ... RList> struct ratio_multiply;
-template <class R1, class R2> struct ratio_divide;
-
    
+
    
+
    
+-1- The behavior of a C++ program is undefined if it adds declarations or
+definitions to namespace std or to a namespace within namespace std
+unless otherwise specified. A program may add a concept map for any
+standard library concept or a template specialization for any standard
+library template to namespace std only if the declaration depends on a
+user-defined type of external linkage and the specialization meets the
+standard library requirements for the original template and is not
+explicitly prohibited.179
+
    
 
 
    
-20.4.2 [ratio.arithmetic] p1: change
+-2- The behavior of a C++ program is undefined if it declares
+
    
+
      
+
    • 
+an explicit specialization of any member function of a standard library
+class template, or
+
      • 
+
    • 
+an explicit specialization of any member function template of a standard
+library class or class template, or
+
      • 
+
    • 
+an explicit or partial specialization of any member class template of a
+standard library class or class template.
+
      • 
+
    
+
    
+A program may explicitly instantiate a template defined in the standard
+library only if the declaration depends on the name of a user-defined
+type of external linkage and the instantiation meets the standard
+library requirements for the original template.
 
    
+
    
 
-
    template <class R1, class R2, class ... RList> struct ratio_add
-  : ratio_add< R1, ratio_add<R2, RList...>> {
-};
 
-template <class R1, class R2> struct ratio_add<R1, R2> {
-  typedef see below type;
-};
-
    
 
 
-
    
-20.4.2 [ratio.arithmetic] p3: change
-
    
 
-
    template <class R1, class R2, class ... RList> struct ratio_multiply
-  : ratio_multiply< R1, ratio_ multiply <R2, RList...>> {
-};
 
-template <class R1, class R2> struct ratio_ multiply<R1, R2> {
-  typedef see below type;
-};
-
    
+
    
+
    1158. Encouragement to use monotonic clock
    
+
    Section: 30.2.4 [thread.req.timing] Status: New
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-05
    
+
    View all issues with New status.
    
+
    Discussion:
    
+
+
    Addresses UK 322, US 96
    
+
+
    Description
    
+        
    Not all systems
+        can provide a monotonic clock. How are they expected to
+        treat a _for function?
    
+
    Suggestion
    
+        
    Add at least a note explaining the intent
+        for systems that do not support a monotonic clock.
    
+
+
    Notes
    
+
    Create an issue, together with UK 96. Note that the specification as is 
+    already allows a non-monotonic clock due to the word “should” rather than 
+    “shall”. If this wording is kept, a footnote should be added to make the 
+    meaning clear.
    
+
+
    [ 2009-06-29 Beman provided a proposed resolution. ] 
    
+    
+
+
+
    Proposed resolution:
    
+
+
    Change Timing specifications 30.2.4 [thread.req.timing] as indicated:
    
+
+
    The member functions whose names end in _for take an argument that
+specifies a relative time. Implementations
+should are encouraged but not required to use a
+monotonic clock to measure time for these functions.
    
 
 
 
@@ -36286,366 +30150,443 @@ template <class R1, class R2> struct ratio_ multiply<R1, R2>
-
    1122. Ratio values should be constexpr
    
-
    Section: 20.4.1 [ratio.ratio] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-25  Last modified: 2009-05-25
    
-
    View other active issues in [ratio.ratio].
    
-
    View all other issues in [ratio.ratio].
    
+
    1159. Unclear spec for resource_deadlock_would_occur
    
+
    Section: 30.4.3.2.2 [thread.lock.unique.locking] Status: New
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-04
    
+
    View other active issues in [thread.lock.unique.locking].
    
+
    View all other issues in [thread.lock.unique.locking].
    
 
    View all issues with New status.
    
 
    Discussion:
    
-
    
-The values num and den in the ratio template
-should be declared constexpr.
-
    
 
+
    Addresses UK 327, UK 328
    
+
+
    UK 327 Description
    
+        
    Not clear what
+        the specification for error condition
+        resource_deadlock_would_occur means. It is perfectly
+        possible for this thread to own the mutex without setting
+        owns to true on this specific lock object. It is also
+        possible for lock operations to succeed even if the thread
+        does own the mutex, if the mutex is recursive. Likewise, if
+        the mutex is not recursive and the mutex has been locked
+        externally, it is not always possible to know that this
+        error condition should be raised, depending on the host
+        operating system facilities. It is possible that 'i.e.' was
+        supposed to be 'e.g.' and that suggests that recursive
+        locks are not allowed. That makes sense, as the
+        exposition-only member owns is boolean and not a integer to
+        count recursive locks.
    
+        
+
    UK 327 Suggestion
    
+        
    Add a precondition !owns. Change the 'i.e.'
+        in the error condition to be 'e.g.' to allow for this
+        condition to propogate deadlock detection by the host OS.
    
+
    UK 327 Notes
    
+
    Create an issue. Assigned to Lawrence Crowl. Note: not sure what try_lock 
+    means for recursive locks when you are the owner. POSIX has language on 
+    this, which should ideally be followed. Proposed fix is not quite right, for 
+    example, try_lock should have different wording from lock.
    
+
+
    UK 328 Description
    
+
+        
    There is a missing precondition that owns
+        is true, or an if(owns) test is missing from the effect
+        clause
    
+
    UK 328 Suggestion
    
+        
    Add a
+        precondition that owns == true. Add an error condition to
+        detect a violation, rather than yield undefined behaviour.
    
+
    UK 328 Notes
    
+
    Handle in same issue as UK 327. Also uncertain that the proposed resolution 
+    is the correct one.
    
 
-
    Proposed resolution:
    
-
    
-20.4.1 [ratio.ratio]
-
    
+    
 
-
    namespace std {
-  template <intmax_t N, intmax_t D = 1>
-  class ratio {
-  public:
-    static constexpr intmax_t num;
-    static constexpr intmax_t den;
-  };
-}
-
    
 
+
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1123. no requirement that standard streams be flushed
    
-
    Section: 27.5.2.1.6 [ios::Init] Status: New
- Submitter: James Kanze Opened: 2009-05-14  Last modified: 2009-05-30
    
-
    View other active issues in [ios::Init].
    
-
    View all other issues in [ios::Init].
    
-
    View all issues with New status.
    
+
    1160. future_error public constructor is 'exposition only'
    
+
    Section: 30.6.3 [futures.future_error] Status: Open
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-17
    
+
    View all issues with Open status.
    
 
    Discussion:
    
-
    
-As currently formulated, the standard doesn't require that there 
-is ever a flush of cout, etc.  (This implies, for example, that 
-the classical hello, world program may have no output.)  In the 
-current draft
-(N2798),
-there is a requirement that the objects 
-be constructed before main, and before the dynamic 
-initialization of any non-local objects defined after the 
-inclusion of <iostream> in the same translation unit.  The only 
-requirement that I can find concerning flushing, however, is in 
-27.5.2.1.6 [ios::Init], where the destructor of the last 
-std::ios_base::Init object flushes.  But there is, as far as I 
-can see, no guarantee that such an object ever exists. 
-
    
-
    
-Also, the wording in  [iostreams.objects] says that:
-
    
-
    
-The objects 
-are constructed and the associations are established at some 
-time prior to or during the first time an object of class 
-ios_base::Init is constructed, and in any case before the body 
-of main begins execution.
-
    
-
    
-In 27.5.2.1.6 [ios::Init], however, as an 
-effect of the constructor, it says that
-
    
-
    
-If init_cnt is zero, 
-the function stores the value one in init_cnt, then constructs 
-and initializes the objects cin, cout, cerr, clog 
-wcin, wcout, wcerr, and wclog"
-
    
 
-
    
-which seems to forbid earlier 
-construction. 
-
    
+
    Addresses UK 331
    
 
-
    
-(Note that with these changes, the exposition only "static 
-int init_cnt" in ios_base::Init can be dropped.) 
-
    
-
    
-Of course, a determined programmer can still inhibit the 
-flush with things like: 
-
    
-
    new std::ios_base::Init ;       //  never deleted 
-
    
-
    
-or (in a function): 
-
    
-
    std::ios_base::Init ensureConstruction ; 
-//  ... 
-exit( EXIT_SUCCESS ) ; 
-
    
-
    
-Perhaps some words somewhere to the effect that all 
-std::ios_base::Init objects should have static lifetime 
-would be in order. 
-
    
+
    Description
    
+        
    Not clear what
+        it means for a public constructor to be 'exposition only'.
+        If the intent is purely to support the library calling this
+        constructor then it can be made private and accessed
+        through friendship. Otherwise it should be documented for
+        public consumption.
    
+
    Suggestion
    
+        
    Declare the constructor as private with a
+        note about intended friendship, or remove the
+        exposition-only comment and document the semantics.
    
+
    Notes
    
+
    Create an issue. Assigned to Detlef. Suggested resolution probably makes 
+    sense.
    
 
+
    [
+2009-07 Frankfurt
+]
    
 
-
    Proposed resolution:
    
-
    
-Change 27.4 [iostream.objects]/2:
-
    
 
 
    
--2- The objects are constructed and the associations are established at
-some time prior to or during the first time an object of class
-ios_base::Init is constructed, and in any case before the body
-of main begins execution.292 The objects are not destroyed
-during program execution.293
-If a translation unit includes
-<iostream> or explicitly constructs an
-ios_base::Init object, these stream objects shall be
-constructed before dynamic initialization of non-local objects defined
-later in that translation unit.
-The results of including <iostream> in a translation
-unit shall be as if <iostream> defined an instance of
-ios_base::Init with static lifetime. Similarly, the entire
-program shall behave as if there were at least one instance of
-ios_base::Init with static lifetime.
+Pending a paper from Anthony Williams / Detleff Volleman.
 
    
 
-
    
-Change 27.5.2.1.6 [ios::Init]/3:
-
    
+
+
+
    Proposed resolution:
    
+
+
+
+
+
+
    
+
    1161. Unnecessary unique_future limitations
    
+
    Section: 30.6.5 [futures.unique_future] Status: Open
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-17
    
+
    View other active issues in [futures.unique_future].
    
+
    View all other issues in [futures.unique_future].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
+
+
    Addresses UK 336
    
+
+
    Description
    
+
+        
    It is possible
+        to transfer ownership of the asynchronous result from one
+        unique_future instance to another via the move-constructor.
+        However, it is not possible to transfer it back, and nor is
+        it possible to create a default-constructed unique_future
+        instance to use as a later move target. This unduly limits
+        the use of unique_future in code. Also, the lack of a
+        move-assignment operator restricts the use of unique_future
+        in containers such as std::vector - vector::insert requires
+        move-assignable for example.
    
+
    Suggestion
    
+        
    Add a default constructor with the
+        semantics that it creates a unique_future with no
+        associated asynchronous result. Add a move-assignment
+        operator which transfers ownership.
    
+
    Notes
    
+
    Create an issue. Detlef will look into it.
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
 
 
    
-
    Init();
-
    
-
    
--3- Effects: Constructs an object of class Init. 
-If init_cnt is zero, the function stores the value one in
-init_cnt, then constructs and initializes the objects
-cin, cout, cerr, clog (27.4.1),
-wcin, wcout, wcerr, and wclog
-(27.4.2). In any case, the function then adds one to the value stored in
-init_cnt.
-Constructs and initializes the objects cin, cout,
-cerr, clog, wcin, wcout,
-wcerr and wclog if they have not already been
-constructed and initialized.
-
    
+Pending a paper from Anthony Williams / Detleff Volleman.
 
    
 
-
    
-Change 27.5.2.1.6 [ios::Init]/4:
-
    
+
+
+
    Proposed resolution:
    
+
+
+
+
+
+
    
+
    1162. shared_future should support an efficient move constructor
    
+
    Section: 30.6.6 [future.shared_future] Status: Open
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-17
    
+
    View other active issues in [future.shared_future].
    
+
    View all other issues in [future.shared_future].
    
+
    View all issues with Open status.
    
+
    Discussion:
    
+
+
    Addresses UK 337
    
+
+
    Description
    
+        
    shared_future
+        should support an efficient move constructor that can avoid
+        unnecessary manipulation of a reference count, much like
+        shared_ptr
    
+
    Suggestion
    
+        
    Add a move constructor
    
+
    Notes
    
+
    Create an issue. Detlef will look into it.
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
 
 
    
-
    ~Init();
-
    
-
    
--4- Effects: Destroys an object of class Init.
-The function subtracts one from the value stored in init_cnt and,
-if the resulting stored value is one,
-If there are no other instances of the class still in
-existance,
-calls cout.flush(),
-cerr.flush(), clog.flush(), wcout.flush(),
-wcerr.flush(), wclog.flush().
-
    
+Pending a paper from Anthony Williams / Detleff Volleman.
 
    
 
 
 
+
    Proposed resolution:
    
+
+
 
 
 
 
    
-
    1124.  Invalid definition of concept RvalueOf
    
-
    Section: 20.2.1 [concept.transform] Status: New
- Submitter: Daniel Krügler Opened: 2009-05-28  Last modified: 2009-05-30
    
-
    View other active issues in [concept.transform].
    
-
    View all other issues in [concept.transform].
    
-
    View all issues with New status.
    
+
    1163. shared_future is inconsistent with shared_ptr
    
+
    Section: 30.6.6 [future.shared_future] Status: Open
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-17
    
+
    View other active issues in [future.shared_future].
    
+
    View all other issues in [future.shared_future].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
-
    
-A recent news group
-article
-points to several defects in the
-specification of reference-related concepts.
-
    
-
    
-One problem of the concept RvalueOf as currently defined in
-20.2.1 [concept.transform]:
-
    
 
-
    concept RvalueOf<typename T> {
- typename type = T&&;
- requires ExplicitlyConvertible<T&,type> && Convertible<T&&,type>;
-}
+
    Addresses UK 338
    
 
-template<typename T> concept_map RvalueOf<T&> {
- typedef T&& type;
-}
-
    
+
    Description
    
 
-
    
-is that if T is an lvalue-reference, the requirement
-Convertible<T&&,type> isn't satisfied for
-lvalue-references, because after reference-collapsing in the concept
-definition we have Convertible<T&,type> in this case,
-which isn't satisfied in the concept map template and also is not the
-right constraint either. I think that the reporter is right that
-SameType requirements should do the job and that we also should
-use the new RvalueReference concept to specify a best matching
-type requirement.
-
    
+        
    shared_future is currently
+        CopyConstructible, but not CopyAssignable. This is
+        inconsistent with shared_ptr, and will surprise users.
+        Users will then write work-arounds to provide this
+        behaviour. We should provide it simply and efficiently as
+        part of shared_future. Note that since the shared_future
+        member functions for accessing the state are all declared
+        const, the original usage of an immutable shared_future
+        value that can be freely copied by multiple threads can be
+        retained by declaring such an instance as "const
+        shared_future".
    
+
    Suggestion
    
+        
    Remove "=delete"
+        from the copy-assignment operator of shared_future. Add a
+        move-constructor shared_future(shared_future&&
+        rhs), and a move-assignment operator shared_future&
+        operator=(shared_future&& rhs). The postcondition
+        for the copy-assignment operator is that *this has the same
+        associated state as rhs. The postcondition for the
+        move-constructor and move assignment is that *this has the
+        same associated as rhs had before the
+        constructor/assignment call and that rhs has no associated
+        state.
    
+
    Notes
    
+
    Create an issue. Detlef will look into it.
    
 
+
    [
+2009-07 Frankfurt
+]
    
 
-
    Proposed resolution:
    
-
    
-In 20.2.1 [concept.transform] before p. 4 change as indicated:
-
    
 
-
    auto concept RvalueOf<typename T> {
-  typenameRvalueReference type = T&&;
-  requires ExplicitlyConvertible<T&, type> && Convertible<T&&, type>SameType<T&, type&>;
-}
-
    
+
    
+Pending a paper from Anthony Williams / Detleff Volleman.
+
    
+
+
+
+
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1125. ostream_iterator does not work with movable types
    
-
    Section: 24.6.2.2 [ostream.iterator.ops] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-28  Last modified: 2009-05-30
    
-
    View all issues with New status.
    
+
    1165. Unneeded promise move constructor
    
+
    Section: 30.6.4 [futures.promise] Status: Open
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-17
    
+
    View other active issues in [futures.promise].
    
+
    View all other issues in [futures.promise].
    
+
    View all issues with Open status.
    
 
    Discussion:
    
-
    
-ostream_iterator has not been updated to support moveable types, in a
-similar manner to the insert iterators.
-Note that this is not a problem for ostreambuf_iterator, as the types it is
-restricted to dealing with do not support extra-efficient moving.
-
    
 
+
    Addresses UK 343
    
 
-
    Proposed resolution:
    
-
    
-Add second operator= overload to class template ostream_iterator
-in 24.6.2 [ostream.iterator], para 2:
-
    
+
    Description
    
+        
    The move constructor of a std::promise
+        object does not need to allocate any memory, so the
+        move-construct-with-allocator overload of the constructor
+        is superfluous.
    
+
    Suggestion
    
+        
    Remove the
+        constructor with the signature template <class
+        Allocator> promise(allocator_arg_t, const Allocator&
+        a, promise& rhs);
    
+
    Notes
    
+
    Create an issue. Detlef will look into it. Will solicit feedback from Pablo. 
+    Note that “rhs” argument should also be an rvalue reference in any case.
    
 
-
    ostream_iterator<T,charT,traits>& operator=(const T& value);
-ostream_iterator<T,charT,traits>& operator=(T&& value);
-
    
+
    [
+2009-07 Frankfurt
+]
    
 
-
    
-Add a new paragraph: in 24.6.2.2 [ostream.iterator.ops]:
-
    
 
 
    
-
    ostream_iterator& operator=(T&& value);
-
    
-
    
-
    
--2- Effects:
-
    
-
    *out_stream << std::move(value);
-if(delim != 0)
-  *out_stream << delim;
-return (*this);
-
    
-
    
+Pending a paper from Anthony Williams / Detleff Volleman.
 
    
 
 
 
+
    Proposed resolution:
    
+
+
 
 
 
 
    
-
    1126. istreambuff_iterator::equal needs a const & parameter
    
-
    Section: 24.6.3.5 [istreambuf.iterator::equal] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-28  Last modified: 2009-05-30
    
-
    View other active issues in [istreambuf.iterator::equal].
    
-
    View all other issues in [istreambuf.iterator::equal].
    
+
    1166. Allocator-specific move/copy break model of move-constructor and
+        move-assignment
    
+
    Section: X [allocator.propagation], X [allocator.propagation.map], 23 [containers] Status: New
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-04
    
 
    View all issues with New status.
    
 
    Discussion:
    
-
    
-The equal member function of istreambuf_iterator is
-declared const, but takes its argument by non-const reference.
-
    
-
    
-This is not compatible with the operator== free function overload, which is
-defined in terms of calling equal yet takes both arguments by reference to
-const.
-
    
 
-
    [
-The proposed wording is consistent with 110 with status TC1.
-]
    
+
    Addresses US 77
    
 
+
    Description
    
+        
    Allocator-specific move and copy behavior for containers
+        (N2525) complicates a little-used and already-complicated
+        portion of the standard library (allocators), and breaks
+        the conceptual model of move-constructor and
+        move-assignment operations on standard containers being
+        efficient operations. The extensions for allocator-specific
+        move and copy behavior should be removed from the working
+        paper.
    
+        
    With the
+        introduction of rvalue references, we are teaching
+        programmers that moving from a standard container (e.g., a
+        vector<string>) is an efficient, constant-time
+        operation. The introduction of N2525 removed that
+        guarantee; depending on the behavior of four different
+        traits (20.8.4), the complexity of copy and move operations
+        can be constant or linear time. This level of customization
+        greatly increases the complexity of standard containers,
+        and benefits only a tiny fraction of the C++ community.
    
+
    Suggestion
    
 
+        
    Remove 20.8.4.
    
+        
+        
    Remove 20.8.5.
    
+        
+        
    Remove all references to the facilities in
+        20.8.4 and 20.8.5 from clause 23.
    
 
 
-
    Proposed resolution:
    
-
    
-Ammend in both:
    
-24.6.3 [istreambuf.iterator]
    
-24.6.3.5 [istreambuf.iterator::equal]
    
-
    
 
-
    bool equal(const istreambuf_iterator& b) const;
-
    
 
+
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1127. rvalue references and iterator traits
    
-
    Section: D.10.1 [iterator.traits] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-28  Last modified: 2009-05-30
    
-
    View all other issues in [iterator.traits].
    
+
    1169. num_get not fully compatible with strto*
    
+
    Section: 22.4.2.1.2 [facet.num.get.virtuals] Status: New
+ Submitter: Cosmin Truta Opened: 2009-07-04  Last modified: 2009-07-07
    
+
    View other active issues in [facet.num.get.virtuals].
    
+
    View all other issues in [facet.num.get.virtuals].
    
 
    View all issues with New status.
    
 
    Discussion:
    
 
    
-The deprecated support for iterator_traits and legacy (unconstrained)
-iterators features the (exposition only) concept:
+As specified in the latest draft,
+N2914,
+num_get is still not fully compatible with the following C
+functions: strtoul, strtoull, 
+strtof and
+strtod.
+
    
+
    
+In C, when conversion of a string to an unsigned integer type falls 
+outside the
+representable range, strtoul and strtoull return
+ULONG_MAX and ULLONG_MAX, respectively, 
+regardless
+whether the input field represents a positive or a negative value.
+On the other hand, the result of num_get conversion of 
+negative
+values to unsigned integer types is zero. This raises a compatibility 
+issue.
 
    
-
-
    concept IsReference<typename T> { } // exposition only
-template<typename T> concept_map IsReference<T&> { }
-
    
 
    
-Now this looks exactly like the LvalueReference concept recently added to
-clause 20, so I wonder if we should use that instead?
-Then I consider the lack of rvalue-reference support, which means that
-move_iterator would always flag as merely supporting the input_iterator_tag
-category.  This suggests we retain the exposition concept, but add a second
-concept_map to support rvalue references.
+Moreover, in C, when conversion of a string to a floating-point type falls
+outside the representable range, strtof, strtod 
+and
+strtold return ±HUGE_VALF,
+±HUGE_VAL and ±HUGE_VALL, respectively.
+On the other hand, the result of num_get conversion of such
+out-of-range floating-point values results in the most positive/negative
+representable value.
+Although many C library implementations do implement HUGE_VAL
+(etc.) as the highest representable (which is, usually, the infinity), 
+this
+isn't required by the C standard. The C library specification makes no
+statement regarding the value of HUGE_VAL and friends, which
+potentially raises the same compatibility issue as in the above case of
+unsigned integers.
+In addition, neither C nor C++ define symbolic constants for the maximum
+representable floating-point values (they only do so only for the maximum
+representable finite floating-point values), which raises a 
+usability
+issue (it would be hard for the programmer to check the result of
+num_get against overflow).
 
    
 
    
-I would suggest adding the extra concept_map is the right way forward, but
-still wonder if the two exposition-only concepts in this clause might be
-worth promoting to clause 20.  That question might better be answered with a
-fuller investigation of type_trait/concept unification though.
+As such, we propose to adjust the specification of num_get to
+closely follow the behavior of all of its underlying C functions.
 
    
 
 
 
    Proposed resolution:
    
+
 
    
-In Iterator traits D.10.1 [iterator.traits] para 4 add:
+Change 22.4.2.1.2 [facet.num.get.virtuals] as follows:
 
    
-
-
    concept IsReference<typename T> { } // exposition only
-template<typename T> concept_map IsReference<T&> { }
-template<typename T> concept_map IsReference<T&&> { }
-
    
+
    
+
    
+Stage 3:
+The sequence of chars accumulated in stage 2 (the field) is
+converted to a numeric value by the rules of one of the functions declared in
+the header <cstdlib>:
+
    
+
      
+
    • For a signed integer value, the function strtoll.
      • 
+
    • For an unsigned integer value, the function strtoull.
      • 
+
    • For a float value, the function
+    strtof.
      • 
+
    • For a double value, the function
+    strtod.
      • 
+
    • For a floating-point long double
+    value, the function strtold.
      • 
+
    
+
    
+The numeric value to be stored can be one of:
+
    
+
      
+
    • zero, if the conversion function fails to convert the entire field.
+    ios_base::failbit is assigned to err.
      • 
+
    • the most positive (or negative) representable value, if
+    the field to be converted to a signed integer type represents a
+    value too large positive (or negative) to be represented in
+    val.
+    ios_base::failbit is assigned to err.
      • 
+
    • the most negative representable value or zero for an unsigned integer
+    type, if the field represents a value too large negative to be represented
+    in val.
+    ios_base::failbit is assigned to err.
      • 
+
    • the most positive representable value, if the field to be converted to
+    an unsigned integer type represents a value that cannot be represented in
+    val.
      • 
+
    • the converted value, otherwise.
      • 
+
    
+
    
+The resultant numeric value is stored in val.
+If the conversion function fails to convert the entire field, or if the
+field represents a value outside the range of representable values,
+ios_base::failbit is assigned to err.
+
    
+
    
 
 
 
@@ -36653,54 +30594,69 @@ template<typename T> concept_map IsReference<T&> { }
 
 
 
    
-
    1128. Missing definition of iterator_traits<T*>
    
-
    Section: 24.3 [iterator.syn] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-28  Last modified: 2009-05-30
    
+
    1170. String char-like types no longer PODs
    
+
    Section: 21.1 [strings.general] Status: New
+ Submitter: Beman Dawes Opened: 2009-06-22  Last modified: 2009-07-28
    
 
    View all issues with New status.
    
 
    Discussion:
    
-
    
-The <iterator> header synopsis declares a partial specialization of
-iterator_traits to support pointers, 24.3 [iterator.syn].  The implication
-is that specialization will be described in D10, yet it did not follow the
-rest of the deprecated material into this clause.
-
    
-
    
-However, this is not as bad as it first seems!
-There are partial specializations of iterator_traits for types that satisfy
-the various Iterator concepts, and there are concept_maps for pointers to
-explicitly support the RandomAccessIterator concept, so the required
-template will be present - just not in the manner advertised.
-
    
-
    
-I can see two obvious solutions:
-
    
 
-
      
-
    1. 
-Restore the iterator_traits<T*> partial specialization in D.10
-
      2. 
-
    2. 
-Remove the declaration of iterator_traits<T*> from 24.3 synopsis
-
      3. 
-
    
-
    
-I recommend option (ii) in the wording below
-
    
-
    
-Option (ii) could be extended to strike all the declarations of deprecated
-material from the synopsis, as it is effectively duplicating D.10 anyway.
-This is the approach taken for deprecated library components in the 98/03
-standards.  This is probably a matter best left to the Editor though.
-
    
+
    Prior to the introduction of constant expressions into the library, 
+basic_string elements had to be POD types, and thus had to be both trivially 
+copyable and standard-layout. This ensured that they could be memcpy'ed and 
+would be compatible with other libraries and languages, particularly the C 
+language and its library.
    
+
    
+N2349,
+Constant Expressions in the Standard Library Revision 2, changed the 
+requirement in 21/1 from "POD type" to "literal type". That change had the 
+effect of removing the trivially copyable and standard-layout requirements from 
+basic_string elements.
    
+
    This means that basic_string elements no longer are guaranteed to be 
+memcpy'able, and are no longer guaranteed to be standard-layout types:
    
+
    
+  
    3.9/p2 and 3.9/p3 both make it clear that a "trivially copyable type" is 
+  required for memcpy to be guaranteed to work.
    
+  
    Literal types (3.9p12) may have a non-trivial copy assignment operator, and 
+  that violates the trivially copyable requirements given in 9/p 6, bullet item 
+  2. 
    
+  
    Literal types (3.9p12) have no standard-layout requirement, either.
    
+
    
+
    This situation probably arose because the wording for "Constant Expressions 
+in the Standard Library" was in process at the same time the C++ POD 
+deconstruction wording was in process. 
    
+
    Since trivially copyable types meet the C++0x requirements for literal types, 
+and thus work with constant expressions, it seems an easy fix to revert the 
+basic_string element wording to its original state.
    
+
+ 
    [
+ 2009-07-28 Alisdair adds:
+ ]
    
+
+ 
+
    
+When looking for any resolution for this issue, consider the definition of
+"character container type" in 17.3.4 [defns.character.container].  This
+does require the character type to be a POD, and this term is used in a
+number of places through clause 21 and 28. This suggests the PODness
+constraint remains, but is much more subtle than before.  Meanwhile, I
+suspect the change from POD type to literal type was intentional with
+the assumption that trivially copyable types with
+non-trivial-but-constexpr constructors should serve as well.  I don't
+believe the current wording offers the right guarantees for either of
+the above designs.
+
    
+
 
 
 
    Proposed resolution:
    
-
    
-In 24.3 [iterator.syn] strike:
-
    
 
-
    template<class T> struct iterator_traits<T*>;
-
    
+
    Change General 21.1 [strings.general] as indicated:
    
+
    
+
    This Clause describes components for manipulating sequences of any literal POD 
+(3.9) type. In this Clause
+such types are called char-like types, and objects of char-like types are 
+called char-like objects or simply characters.
    
+
    
 
 
 
@@ -36708,1069 +30664,1319 @@ In 24.3 [iterator.syn] strike:
 
 
 
    
-
    1129. istream(buf)_iterator should support literal sentinel value
    
-
    Section: 24.6.1.1 [istream.iterator.cons], 24.6.3 [istreambuf.iterator] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-30  Last modified: 2009-06-09
    
+
    1171. duration types shoud be literal
    
+
    Section: 20.9.3 [time.duration] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-07-06  Last modified: 2009-07-07
    
+
    View other active issues in [time.duration].
    
+
    View all other issues in [time.duration].
    
 
    View all issues with New status.
    
 
    Discussion:
    
 
    
-istream_iterator and istreambuf_iterator should support literal sentinel
-values.  The default constructor is frequently used to terminate ranges, and
-could easily be a literal value for istreambuf_iterator, and
-istream_iterator when iterating value types.  A little more work using a
-suitably sized/aligned char-array for storage (or an updated component like
-boost::optional proposed for TR2) would allow istream_iterator to support
-constexpr default constructor in all cases, although we might leave this
-tweak as a QoI issue.  Note that requiring constexpr be supported also
-allows us to place no-throw guarantees on this constructor too.
+The duration types in 20.9.3 [time.duration] are exactly the sort of type
+that should be "literal types" in the new standard.  Likewise,
+arithmetic operations on durations should be declared constexpr.
 
    
 
-
    [
-2009-06-02 Daniel adds:
-]
    
-
 
-
    
-
    
-I agree with the usefulness of the issue suggestion, but we need
-to ensure that istream_iterator can satisfy be literal if needed.
-Currently this is not clear, because 24.6.1 [istream.iterator]/3 declares
-a copy constructor and a destructor and explains their semantic in
-24.6.1.1 [istream.iterator.cons]/3+4.
-
    
-
    
-The prototype semantic specification is ok (although it seems
-somewhat redundant to me, because the semantic doesn't say
-anything interesting in both cases), but for support of trivial class
-types we also need a trivial copy constructor and destructor as of
-9 [class]/6. The current non-informative specification of these
-two special members suggests to remove their explicit declaration
-in the class and add explicit wording that says that if T is
-trivial a default constructed iterator is also literal, alternatively it
-would be possible to mark both as defaulted and add explicit
-(memberwise) wording that guarantees that they are trivial.
-
    
-
    
-Btw.: I'm quite sure that the istreambuf_iterator additions to
-ensure triviality are not sufficient as suggested, because the
-library does not yet give general guarantees that a defaulted
-special member declaration makes this member also trivial.
-Note that e.g. the atomic types do give a general statement!
-
    
-
    
-Finally there is a wording issue: There does not exist something
-like a "literal constructor". The core language uses the term
-"constexpr constructor" for this.
-
    
-
    
-Suggestion:
-
    
-
      
-
    1. 
-
      
-Change 24.6.1 [istream.iterator]/3 as indicated:
-
      
-
      constexpr istream_iterator();
-istream_iterator(istream_type& s);
-istream_iterator(const istream_iterator<T,charT,traits,Distance>& x) = default;
-~istream_iterator() = default;
-
      
-
      2. 
-
    2. 
-
      
-Change 24.6.1.1 [istream.iterator.cons]/1 as indicated:
-
      
-
      constexpr istream_iterator();
-
      
-
      
--1- Effects: Constructs the end-of-stream iterator. If T is a literal type,
-then this constructor shall be a constexpr constructor.
-
      
-
      
-
      3. 
-
    3. 
+
      Proposed resolution:
      
 
      
-Change 24.6.1.1 [istream.iterator.cons]/3 as indicated:
+Add constexpr to declaration of following functions and constructors:
 
      
-
      istream_iterator(const istream_iterator<T,charT,traits,Distance>& x) = default;
-
      
-
      
--3- Effects: Constructs a copy of x. If T is a literal type, then
-this constructor shall be a trivial copy constructor.
-
      
-
      
-
      4. 
-
    4. 
 
      
-Change 24.6.1.1 [istream.iterator.cons]/4 as indicated:
+p1 20.9 [time]
 
      
 
-
      ~istream_iterator() = default;
-
      
 
      
--4- Effects: The iterator is destroyed. If T is a literal type, then
-this destructor shall be a trivial
-destructor.
-
      
-
      
-
      5. 
-
    5. 
-
      
-Change 24.6.3 [istreambuf.iterator] before p. 1 as indicated:
-
      
-
-
      constexpr istreambuf_iterator() throw();
-istreambuf_iterator(const istreambuf_iterator&)  throw() = default;
-~istreambuf_iterator()  throw() = default;
-
      
-
      6. 
-
    6. 
 
      
-Change 24.6.3 [istreambuf.iterator]/1 as indicated:
+Header <chrono> synopsis
 
      
-
      
-[..] The default constructor istreambuf_iterator() and the constructor
-istreambuf_iterator(0) both
-construct an end of stream iterator object suitable for use as an
-end-of-range. All
-specializations of istreambuf_iterator shall have a trivial copy
-constructor, a constexpr default
-constructor and a trivial destructor.
-
      
-
      7. 
-
    
-
    
 
+
    [Draughting note - observe switch to pass-by-value to support constexpr]
    
 
-
    Proposed resolution:
    
-
    
-24.6.1 [istream.iterator] para 3
-
    
 
-
    constexpr istream_iterator();
-
    
+
    // duration arithmetic
+template <class Rep1, class Period1, class Rep2, class Period2>
+   typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
+   constexpr operator+(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
+   constexpr operator-(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period, class Rep2>
+   duration<typename common_type<Rep1, Rep2>::type, Period>
+   constexpr operator*(const duration<Rep1, Period>& d, const Rep2& s);
+template <class Rep1, class Period, class Rep2>
+   duration<typename common_type<Rep1, Rep2>::type, Period>
+   constexpr operator*(const Rep1& s, const duration<Rep2, Period>& d);
+template <class Rep1, class Period, class Rep2>
+   duration<typename common_type<Rep1, Rep2>::type, Period>
+   constexpr operator/(const duration<Rep1, Period>& d, const Rep2& s);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   typename common_type<Rep1, Rep2>::type
+   constexpr operator/(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
 
-
    
-24.6.1.1 [istream.iterator.cons]
-
    
+// duration comparisons
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr bool operator==(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr bool operator!=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr bool operator< (const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr bool operator<=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr bool operator> (const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr bool operator>=(const  duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
 
-
    constexpr istream_iterator();
+// duration_cast
+template <class ToDuration, class Rep, class Period>
+   constexpr ToDuration duration_cast(const duration<Rep, Period>& d);
 
    
-
    
--1- Effects: Constructs the end-of-stream iterator.
-If T is a literal type, then this constructor shall
-be a literal constructor.
-
    
-
    
 
 
    
-24.6.3 [istreambuf.iterator]
+20.9.3 [time.duration]
 
    
 
-
    constexpr istreambuf_iterator() throw();
-
    
+
    template <class Rep, class Period = ratio<1>>
+class duration {
+  ....
+public:
+  // 20.9.3.1, construct/copy/destroy:
+ constexpr duration() = default;
 
+ template <class Rep2>
+   constexpr explicit duration(const Rep2& r);
+ template <class Rep2, class Period2>
+   constexpr duration(const duration<Rep2, Period2>& d);
 
+  constexpr duration(const duration&) = default;
 
+  // 20.9.3.2, observer:
+  constexpr rep count() const;
 
+  // 20.9.3.3, arithmetic:
+  constexpr duration operator+() const;
+  constexpr duration operator-() const;
+  ...
 
+};
+
    
+
    
+
    [
+Note - this edit already seems assumed by definition of the duration static members zero/min/max.
+They cannot meaningfully be constexpr without this change.
+]
    
 
-
    
-
    1130. copy_exception name misleading
    
-
    Section: 18.8.5 [propagation] Status: New
- Submitter: Peter Dimov Opened: 2009-05-13  Last modified: 2009-06-02
    
-
    View other active issues in [propagation].
    
-
    View all other issues in [propagation].
    
-
    View all issues with New status.
    
-
    Discussion:
    
-
    
-The naming of std::copy_exception misleads almost everyone
-(experts included!) to think that it is the function that copies an
-exception_ptr:
-
    
 
-
    exception_ptr p1 = current_exception();
-exception_ptr p2 = copy_exception( p1 );
-
    
 
+
+
+
+
    
+
    1172. select_on_container_(copy|move)_construction over-constrained
    
+
    Section: 20.8.2.4 [allocator.concepts.members] Status: New
+ Submitter: Alberto Ganesh Barbati Opened: 2009-07-08  Last modified: 2009-07-14
    
+
    View all issues with New status.
    
+
    Discussion:
    
 
    
-But this is not at all what it does. The above actually creates an
-exception_ptr p2 that contains a copy of p1, not of
-the exception to which p1 refers!
-
    
-
    
-This is, of course, all my fault; in my defence, I used copy_exception
-because I was unable to think of a better name.
+I believe the two functions
+select_on_container_(copy|move)_construction() are over-constrained. For
+example, the return value of the "copy" version is (see
+20.8.2.4 [allocator.concepts.members]/21):
 
    
+
    
+Returns: x if the allocator should propagate from the existing
+container to the new container on copy construction, otherwise X().
+
    
 
    
-But I believe that, based on what we've seen so far, any other name would be better.
+Consider the case where a user decides to provide an explicit concept
+map for Allocator to adapt some legacy allocator class, as he wishes to
+provide customizations that the LegacyAllocator concept map template
+does not provide.  Now, although it's true that the legacy class is
+required to have a default constructor, the user might have reasons to
+prefer a different constructor to implement
+select_on_container_copy_construction(). However, the current wording
+requires the use of the default constructor.
 
    
 
    
-Therefore, I propose copy_exception to be renamed to
-create_exception:
+Moreover, it's not said explicitly that x is supposed to be the
+allocator of the existing container. A clarification would do no harm.
 
    
 
-
    template<class E> exception_ptr create_exception(E e);
-
    
 
+
    Proposed resolution:
    
 
    
-with the following explanatory paragraph after it:
+Replace 20.8.2.4 [allocator.concepts.members]/21 with:
 
    
 
-
    
-Creates an exception_ptr that refers to a copy of e.
-
    
-
-
    [
-2009-05-13 Daniel adds:
-]
    
-
-
-
    
+
    X select_on_container_copy_construction(const X& x);
+
    
 
    
-What about
+-21- Returns: x if the allocator should propagate from the existing
+container to the new container on copy construction, otherwise X().
+an allocator object to be used by the new container on copy
+construction. [Note: x is the allocator of the existing container that
+is being copied. The most obvious choices for the return value are x, if
+the allocator should propagate from the existing container, and X().
+— end note]
 
    
-
    make_exception_ptr
-
    
+
    
+
 
    
-in similarity to make_pair and make_tuple, make_error_code and
-make_error_condition, or make_shared? Or, if a stronger symmetry to
-current_exception is preferred:
+Replace 20.8.2.4 [allocator.concepts.members]/25 with:
 
    
 
-
    make_exception
-
    
+
    X select_on_container_move_construction(X&& x);
+
    
 
    
-We have not a single create_* function in the library, it was always
-make_* used.
+-25- Returns: move(x) if the allocator should propagate from the existing
+container to the new container on move construction, otherwise X().
+an allocator object to be used by the new container on move
+construction. [Note: x is the allocator of the existing container that
+is being moved. The most obvious choices for the return value are move(x), if
+the allocator should propagate from the existing container, and X().
+— end note]
 
    
 
    
 
-
    [
-2009-05-13 Peter adds:
-]
    
 
 
-
    
-make_exception_ptr works for me.
-
    
 
-
    [
-2009-06-02 Thomas J. Gritzan adds:
-]
    
 
 
-
    
+
    
+
    1173. "Equivalence" wishy-washiness
    
+
    Section: 17 [library] Status: New
+ Submitter: David Abrahams Opened: 2009-07-14  Last modified: 2009-07-14
    
+
    View other active issues in [library].
    
+
    View all other issues in [library].
    
+
    View all issues with New status.
    
+
    Discussion:
    
 
    
-To avoid surprises and unwanted recursion, how about making a call to
-std::make_exception_ptr with an exception_ptr illegal?
+Issue: The CopyConstructible requirements are wishy-washy.  It requires
+that the copy is "equivalent" to the original, but "equivalent" is never
+defined.
 
    
 
    
-It might work like this:
+I believe this to be an example of a more general lack of rigor around
+copy and assignment, although I haven't done the research to dig up all
+the instances.
 
    
-
    template<class E>
-exception_ptr make_exception_ptr(E e);
-template<>
-exception_ptr make_exception_ptr<exception_ptr>(exception_ptr e) = delete;
-
    
-
    
-
-
-
-
    Proposed resolution:
    
 
    
-Change 18.8.5 [propagation]:
+It's a problem because if you don't know what CopyConstructible means,
+you also don't know what it means to copy a pair of CopyConstructible
+types.  It doesn't prevent us from writing code, but it is a hole in our
+ability to understand the meaning of copy.
 
    
-
-
    
-
    template<class E> exception_ptr copy_exceptionmake_exception_ptr(E e);
-
    
-
-
    
 
    
--11- Effects: Creates an exception_ptr that refers
-to a copy of e, as if
+Furthermore, I'm pretty sure that vector's copy constructor doesn't
+require the elements to be EqualityComparable, so that table is actually
+referring to some ill-defined notion of equivalence when it uses ==.
 
    
 
-
    try {
-  throw e;
-} catch(...) {
-  return current_exception();
-}
-
    
-
-
    ...
    
-
    
-
-
    
 
+
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1131. C++0x does not need alignment_of
    
+
    1174. 	type property predicates
    
 
    Section: 20.6.4.3 [meta.unary.prop] Status: New
- Submitter: Niels Dekker Opened: 2009-06-01  Last modified: 2009-06-02
    
+ Submitter: Jason Merrill Opened: 2009-07-16  Last modified: 2009-07-17
    
 
    View other active issues in [meta.unary.prop].
    
 
    View all other issues in [meta.unary.prop].
    
 
    View all issues with New status.
    
 
    Discussion:
    
 
    
-The alignment_of template is no longer necessary, now that the
-core language will provide alignof. Scott Meyers raised this
-issue at comp.std.c++,
-C++0x: alignof vs. alignment_of,
-May 21, 2009.  In a reply, Daniel Krügler pointed out that
-alignof was added to the working paper after
-alignment_of. So it appears that alignment_of is only
-part of the current Working Draft 
-(N2857)
-because it is in TR1.
-
    
-
    
-Having both alignof and alignment_of would cause
-unwanted confusion. In general, I think TR1 functionality should not be
-brought into C++0x if it is entirely redundant with other C++0x language
-or library features.
+I've been implementing compiler support for is_standard_layout, and
+noticed a few nits about 20.6.4.3 [meta.unary.prop]:
 
    
 
+
      
+
    1. 
+There's no trait for "trivially copyable type", which is now the
+property that lets you do bitwise copying of a type, and therefore seems
+useful to be able to query.  has_trivial_assign &&
+has_trivial_copy_constructor && has_trivial_destructor
+is similar, but
+not identical, specifically with respect to const types.
+
      2. 
+
    2. 
+has_trivial_copy_constructor and has_trivial_assign lack the "or an
+array of such a class type" language that most other traits in that
+section, including has_nothrow_copy_constructor and has_nothrow_assign,
+have; this seems like an oversight.
+
      3. 
+
    
+
+
    [
+See the thread starting with c++std-lib-24420 for further discussion.
+]
    
+
 
-
    Proposed resolution:
    
-
    
-Remove from Header <type_traits> synopsis 20.6.2 [meta.type.synop]:
-
    
-
    template <class T> struct alignment_of;
-
    
 
-
    
-Remove the first row of Table 34 ("Type property queries"), from
-Type properties 20.6.4.3 [meta.unary.prop]:
-
    
-
    
-
-
-
-
-
-
-
    Table 34 -- Type property queries
    template <class T> struct alignment_of;alignof(T).
    
-Precondition: T shall be a complete type, a reference
-type, or an array of unknown bound, but shall not be a function type or
-(possibly cv-qualified) void.
-
    
-
    
 
+
    Proposed resolution:
    
 
    
-Change text in Table 41 ("Other transformations"), from Other
-transformations 20.6.7 [meta.trans.other], as follows:
 
    
-
    
-
-
-
-
-
-
    Table 41 -- Other transformations
    ...
- Align shall be equal to 
- alignment_of<T>::value
- alignof(T)
-  for some type T or to default-alignment.
-...
    
-
    
 
 
 
 
 
 
    
-
    1132. JP-30: nested exceptions
    
-
    Section: 18.8.6 [except.nested] Status: New
- Submitter: Seiji Hayashida Opened: 2009-06-01  Last modified: 2009-06-02
    
-
    View other active issues in [except.nested].
    
-
    View all other issues in [except.nested].
    
+
    1175. unordered complexity
    
+
    Section: 23.2.5 [unord.req] Status: New
+ Submitter: Pablo Halpern Opened: 2009-07-17  Last modified: 2009-07-19
    
+
    View other active issues in [unord.req].
    
+
    View all other issues in [unord.req].
    
 
    View all issues with New status.
    
 
    Discussion:
    
-
    Addresses JP 30
    
-
-
    
-C++0x nested_exception cannot handle a structured exception well. The
-following codes show two types of tree structured exception handling.
-
    
 
    
-The first one is based on nested_exception in C++0x,
-while the second one is based on my library trickerr.h (in Japanese).
-http://tricklib.com/cxx/dagger/trickerr.h
+When I look at the unordered_* constructors, I think the complexity is poorly
+described and does not follow the style of the rest of the standard.
 
    
+
 
    
-Assume that Function A() calls two sub functions A_a() and A_b(), both might
-throw tree structured exceptions, and A_b() must be called even if A_a()
-throws an exception.
+The complexity for the default constructor is specified as constant.
+ Actually, it is proportional to n, but there are no invocations of
+value_type constructors or other value_type operations.
 
    
+
 
    
-List A (code of tree structured exception handling based on nested_exception
-in C++0x)
+For the iterator-based constructor the complexity should be:
 
    
 
-
    void A()
-{
-    try
-    {
-        std::vector<exception_ptr> exception_list;
-        try
-        {
-            // A_a() does a similar processing as A().
-            A_a();
-        }
-        catch(...)
-        {
-            exception_list.push_back(current_exception());
-        }
-
-        // ***The processing A() has to do even when A_a() fails. ***
-        try
-        {
-            // A_b() does a similar processing as A().
-            A_b();
-        }
-        catch(...)
-        {
-            exception_list.push_back(current_exception());
-        }
-        if (!exception_list.empty())
-        {
-            throw exception_list;
-        }
-    }
-    catch(...)
-    {
-        throw_with_nested(A_exception("someone error"));
-    }
-}
-void print_tree_exception(exception_ptr e, const std::string & indent ="")
-{
-    const char * indent_unit = " ";
-    const char * mark = "- ";
-    try
-    {
-        rethow_exception(e);
-    }
-    catch(const std::vector<exception_ptr> e)
-    {
-        for(std::vector<exception_ptr>::const_iterator i = e.begin(); i!=e.end(); ++i)
-        {
-            print_tree_exception(i, indent);
-        }
-    }
-    catch(const std::nested_exception  e)
-    {
-        print_tree_exception(evil_i(e), indent +indent_unit);
-    }
-    catch(const std::exception e)
-    {
-        std::cout << indent << mark << e.what() << std::endl;
-    }
-    catch(...)
-    {
-        std::cout << indent << mark << "unknown exception" << std::endl;
-    }
-}
-int main(int, char * [])
-{
-    try
-    {
-        A();
-    }
-    catch()
-    {
-        print_tree_exception(current_exception());
-    }
-    return EXIT_SUCCESS;
-}
-
    
-
+
    
+Complexity: exactly n calls to construct value_type
+from InputIterator::value_type (where n = distance(f,l)).
+The number of calls to key_equal::operator() is proportional to
+n in the average case and n*n in the worst case.
+
    
+
+
+
+
    Proposed resolution:
    
 
    
-List B ( code of tree structured exception handling based on trickerr.h. )
-"trickerr.h" (in Japanese), refer to:
-http://tricklib.com/cxx/dagger/trickerr.h.
 
    
 
-
    void A()
-{
-    tricklib::error_listener_type error_listener;
-    // A_a() is like A(). A_a() can throw tree structured exception.
-    A_a();
 
-    // *** It must do process so that A_a() throws exception in A(). ***
-    // A_b() is like A(). A_b() can throw tree structured exception.
-    A_b();
 
-    if (error_listener.has_error()) // You can write this "if block" in destructor
-                                    //  of class derived from error_listener_type.
-    {
-        throw_error(new A_error("someone error",error_listener.listener_off().extract_pending_error()));
-    }
-}
-void print_tree_error(const tricklib::error_type &a_error, const std::string & indent = "")
-{
-    const char * indent_unit = " ";
-    const char * mark = "- ";
 
-    tricklib::error_type error = a_error;
-    while(error)
-    {
-        std::cout << indent << mark << error->message << std::endl;
-        if (error->children)
-        {
-            print_tree_error(error->children, indent +indent_unit);
-        }
-        error = error->next;
-    }
-}
-int main(int, char * [])
-{
-    tricklib::error_thread_power error_thread_power_on; // This object is necessary per thread.
 
-    try
-    {
-        A();
-    }
-    catch(error_type error)
-    {
-        print_tree_error(error);
-    }
-    catch(...)
-    {
-        std::cout << "- unknown exception" << std::endl;
-    }
-    return EXIT_SUCCESS;
-}
+
    
+
    1176. Make thread constructor non-variadic
    
+
    Section: 30.3.1.2 [thread.thread.constr] Status: New
+ Submitter: Howard Hinnant Opened: 2009-07-18  Last modified: 2009-07-18
    
+
    View other active issues in [thread.thread.constr].
    
+
    View all other issues in [thread.thread.constr].
    
+
    View all issues with New status.
    
+
    Discussion:
    
+
    
+The variadic thread constructor is causing controversy, e.g.
+N2901.
+This issue has been created as a placeholder for this course of action.
+
    
+
+
    template <class F, class ...Args> thread(F&& f, Args&&... args);
 
    
 
 
    
-Prospect
+See 929 for wording which specifies an rvalue-ref signature but
+with "decay behavior", but using variadics.
 
    
+
+
+
    Proposed resolution:
    
 
    
-We will focus on the method A() since the other methods, also main(), occur
-only once respectively.
 
    
 
+
+
+
+
+
    
+
    1177. Improve "diagnostic required" wording
    
+
    Section: 20.9.3 [time.duration] Status: New
+ Submitter: Howard Hinnant Opened: 2009-07-18  Last modified: 2009-08-01
    
+
    View other active issues in [time.duration].
    
+
    View all other issues in [time.duration].
    
+
    View all issues with New status.
    
+
    Discussion:
    
+
    
+"diagnostic required" has been used (by me) for code words meaning "use
+enable_if to constrain templated functions.  This needs to be
+improved by referring to the function signature as not participating in
+the overload set, and moving this wording to a Remarks paragraph.
+
    
+
+
+
+
    Proposed resolution:
    
+
    [
+This proposed resolution addresses 947 and 974. 
+]
    
+
+
+
    
+Change 20.9.3.1 [time.duration.cons]:
+
    
+
+
    
+
    template <class Rep2> 
+  explicit duration(const Rep2& r);
+
    
+
    
+
    
+Requires: Remarks:
+Rep2 shall be implicitly convertible to rep and
+
    
 
      
 
    • 
- In the List A above (of the nested exception handling), it is hard to
- find out an active reason to use the nested exception handling at this
- scene. Rather, we can take a simpler description by throwing the entire
- exception_list directly to the top level.
+treat_as_floating_point<rep>::value shall be true or
 
      • 
 
    • 
- The code in the same example gives us a kind of redundant impression,
- which might have come from the fact that the try-throw-catch framework does
- not assume a tree structured exception handling.
+treat_as_floating_point<Rep2>::value shall be false.
 
      • 
 
    
+
    
+Diagnostic required If these constraints are not met, this
+constructor shall not participate in overload resolution. [Example:
+
    
+
    duration<int, milli> d(3); // OK 
+duration<int, milli> d(3.5); // error 
+
    
 
 
    
-According to the above observation, we cannot help concluding that it is not
-so easy to use the nested_exception handling as a tree structured exception
-handling mechanism in a practical sense.
+— end example]
 
    
+
 
    
-This text is based on the web page below (in Japanese).
-http://d.hatena.ne.jp/wraith13/20081231/1230715424
+Effects: Constructs an object of type duration.
+
    
+
+
    
+Postcondition: count() == static_cast<rep>(r).
+
    
+
+
    
+
+
    template <class Rep2, class Period2>
+  duration(const duration<Rep2, Period2>& d);
+
    
+
    
+
    
+Requires: Remarks: treat_as_floating_point<rep>::value shall be true or
+ratio_divide<Period2, period>::type::den shall be 1. Diagnostic
+required, else this constructor shall not participate in overload
+resolution. [Note: This requirement prevents implicit truncation error
+when converting between integral-based duration types. Such a
+construction could easily lead to confusion about the value of the
+duration. — end note] [Example:
+
    
+
+
    duration<int, milli> ms(3); 
+duration<int, micro> us = ms; // OK 
+duration<int, milli> ms2 = us; // error 
+
    
+
+
    
+— end example]
+
    
+
+
    
+Eff�ects: Constructs an object of type duration, constructing
+rep_ from
+duration_cast<duration>(d).count().
+
    
+
+
    
+
+
+
    
+
+
    
+Change the following paragraphs in 20.9.3.5 [time.duration.nonmember]:
+
    
+
+
    
+
    template <class Rep1, class Period, class Rep2> 
+  duration<typename common_type<Rep1, Rep2>::type, Period> 
+  operator*(const duration<Rep1, Period>& d, const Rep2& s);
+
    
+
    
+Requires Remarks: Rep2 shall be implicitly convertible to
+CR(Rep1, Rep2), else this signature shall not participate in
+overload resolution. Diagnostic required.
+
    
+
+
    template <class Rep1, class Period, class Rep2> 
+  duration<typename common_type<Rep1, Rep2>::type, Period> 
+  operator*(const Rep1& s, const duration<Rep2, Period>& d);
+
    
+
    
+Requires Remarks: Rep1 shall be implicitly convertible to
+CR(Rep1, Rep2), else this signature shall not participate in
+overload resolution. Diagnostic required.
+
    
+
+
    template <class Rep1, class Period, class Rep2> 
+  duration<typename common_type<Rep1, Rep2>::type, Period> 
+  operator/(const duration<Rep1, Period>& d, const Rep2& s);
+
    
+
    
+Requires Remarks: Rep2 shall be implicitly convertible to
+CR(Rep1, Rep2) and Rep2 shall not be an instantiation of
+duration, else this signature shall not participate in
+overload resolution. Diagnostic required.
+
    
+
+
    template <class Rep1, class Period, class Rep2> 
+  duration<typename common_type<Rep1, Rep2>::type, Period> 
+  operator%(const duration<Rep1, Period>& d, const Rep2& s);
+
    
+
    
+Requires Remarks: Rep2 shall be implicitly convertible to
+CR(Rep1, Rep2) and Rep2 shall not be an instantiation of
+duration, else this signature shall not participate in
+overload resolution. Diagnostic required.
+
    
+
+
    
+
+
+
+
+
+
+
    
+
    1178. Header dependencies
    
+
    Section: 17.6.4.2 [res.on.headers] Status: Ready
+ Submitter: Beman Dawes Opened: 2009-07-18  Last modified: 2009-07-18
    
+
    View all issues with Ready status.
    
+
    Discussion:
    
+
    
+See Frankfurt notes of 1001.
 
    
 
 
 
    Proposed resolution:
    
+
    Change 17.6.4.2 [res.on.headers], Headers, paragraph 1, as indicated:
    
+
+
    
+
 
    
+A C++ header may include other C++
+headers.[footnote] A C++ header shall provide
+the declarations and definitions that appear in its synopsis
+(3.2 [basic.def.odr]). A C++ header shown in its synopsis as including 
+other C++ headers shall provide the declarations and definitions that appear in
+the synopses of those other headers.
 
    
 
+  
    [footnote] C++ headers must include a C++ header that contains 
+  any needed definition (3.2).
    
+
    
+
+
 
 
 
 
 
    
-
    1133. Does N2844 break current specification of list::splice?
    
-
    Section: 23.3.3.5 [forwardlist.ops], 23.3.4.4 [list.ops] Status: New
- Submitter: Alisdair Meredith Opened: 2009-05-09  Last modified: 2009-06-09
    
-
    View other active issues in [forwardlist.ops].
    
-
    View all other issues in [forwardlist.ops].
    
+
    1179. Probably editorial in [structure.specifications]
    
+
    Section: 17.5.1.4 [structure.specifications] Status: New
+ Submitter: Robert Klarer Opened: 2009-07-21  Last modified: 2009-07-22
    
+
    View all other issues in [structure.specifications].
    
 
    View all issues with New status.
    
 
    Discussion:
    
 
    
-IIUC,
-N2844
-means that lvalues will no longer bind to rvalue references.
-Therefore, the current specification of list::splice (list
-operations 23.3.4.4 [list.ops]) will be a breaking change of behaviour for existing
-programs.  That is because we changed the signature to swallow via an rvalue
-reference rather than the lvalue reference used in 03.
+While reviewing 971 I noted that 17.5.1.4 [structure.specifications]/7 says:
 
    
+
+
    
+-7- Error conditions specify conditions where a function may fail. The
+conditions are listed, together with a suitable explanation, as the enum
+class errc constants (19.5) that could be used as an argument to
+function make_error_condition (19.5.3.6).
+
    
+
 
    
-Retaining this form would be safer, requiring an explicit move when splicing
-from lvalues.  However, this will break existing programs.
-We have the same problem with forward_list, although without the risk of
-breaking programs so here it might be viewed as a positive feature.
+This paragraph should mention make_error_code or the text "that
+could be used as an argument to function make_error_condition
+(19.5.3.6)" should be deleted.  I believe this is editorial.
 
    
+
+
    [
+2009-07-21 Chris adds:
+]
    
+
+
+
    
 
    
-The problem signatures:
+I'm not convinced there's a problem there, because as far as the "Error
+conditions" clauses are concerned, make_error_condition() is used by a
+user to test for the condition, whereas make_error_code is not. For
+example:
 
    
-
    void splice_after(const_iterator position, forward_list<T,Alloc>&& x);
-void splice_after(const_iterator position, forward_list<T,Alloc>&& x,
-                  const_iterator i);
-void splice_after(const_iterator position, forward_list<T,Alloc>&& x,
-                  const_iterator first, const_iterator last);
 
-void splice(const_iterator position, list<T,Alloc>&& x);
-void splice(const_iterator position, list<T,Alloc>&& x,
-            const_iterator i);
-void splice(const_iterator position, list<T,Alloc>&& x,
-            const_iterator first, const_iterator last);
+
    void foobar(error_code& ec = throws());
 
    
 
-Possible resolutions:
+
    
+ Error conditions:
+
    
+
    
+permission_denied - Insufficient privilege to perform operation.
+
    
 
 
    
-Option A.	Add an additional (non-const) lvalue-reference
-overload in each case
+When a user writes:
 
    
+
+
    error_code ec;
+foobar(ec);
+if (ec == errc::permission_denied)
+   ...
+
    
+
 
    
-Option B.	Change rvalue reference back to (non-const)
-lvalue-reference overload in each case
+the implicit conversion errc->error_condition makes the if-test
+equivalent to:
 
    
+
+
    if (ec == make_error_condition(errc::permission_denied))
+
    
+
 
    
-Option C.	Add an additional (non-const) lvalue-reference
-overload in just the std::list cases
+On the other hand, if the user had written:
+
    
+
+
    if (ec == make_error_code(errc::permission_denied))
+
    
+
+
    
+the test is now checking for a specific error code. The test may
+evaluate to false even though foobar() failed due to the documented
+error condition "Insufficient privilege".
+
    
+
    
+
+
+
    Proposed resolution:
    
+
    
+
    
+
+
+
+
+
+
    
+
    1180. Missing string_type member typedef in class sub_match
    
+
    Section: 28.9.1 [re.submatch.members] Status: New
+ Submitter: Daniel Krügler Opened: 2009-07-25  Last modified: 2009-07-26
    
+
    View all issues with New status.
    
+
    Discussion:
    
+
    
+The definition of class template sub_match is strongly dependent
+on the type basic_string<value_type>, both in interface and effects,
+but does not provide a corresponding typedef string_type, as e.g.
+class match_results does, which looks like an oversight to me that
+should be fixed.
 
    
+
+
+
    Proposed resolution:
    
+
+
      
+
    1. 
 
      
-I think (B) would be very unfortunate, I really like the forward_list
-behaviour in (C) but feel (A) is needed for consistency.
+In the class template sub_match synopsis 28.9 [re.submatch]/1
+change as indicated:
 
      
+
+
      template <class BidirectionalIterator>
+class sub_match : public std::pair<BidirectionalIterator, BidirectionalIterator> {
+public:
+  typedef typename iterator_traits<BidirectionalIterator>::value_type value_type;
+  typedef typename iterator_traits<BidirectionalIterator>::difference_type difference_type;
+  typedef BidirectionalIterator iterator;
+  typedef basic_string<value_type> string_type;
+
+  bool matched;
+
+  difference_type length() const;
+  operator basic_string<value_type>string_type() const;
+  basic_string<value_type>string_type str() const;
+  int compare(const sub_match& s) const;
+  int compare(const basic_string<value_type>string_type& s) const;
+  int compare(const value_type* s) const;
+};
+
      
+
      2. 
+
+
    2. 
 
      
-My actual preference would be NAD, ship with this as a breaking change as it
-is a more explicit interface.  I don't think that will fly though!
+In 28.9.1 [re.submatch.members]/2 change as indicated:
 
      
 
+
      operator basic_string<value_type>string_type() const;
+
      
+
+
      
+Returns: matched ? basic_string<value_type>
+string_type(first, second) : basic_string<value_type>
+string_type().
+
      
+
      
+
      3. 
+
+
    3. 
 
      
-See the thread starting with c++std-lib-23725 for more discussion.
+In 28.9.1 [re.submatch.members]/3 change as indicated:
 
      
 
+
      basic_string<value_type>string_type str() const;
+
      
+
+
      
+Returns: matched ? basic_string<value_type>
+string_type(first, second) : basic_string<value_type>
+string_type().
+
      
+
      
+
      4. 
+
    
 
-
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1134. Redundant specification of stdint.h, fenv.h, tgmath.h, and maybe complex.h
    
-
    Section: 18.4.2 [stdinth], 26.3.2 [fenv], 26.8 [c.math], 26.4.11 [cmplxh] Status: New
- Submitter: Robert Klarer Opened: 2009-05-26  Last modified: 2009-06-14
    
+
    1181. Invalid sub_match comparison operators
    
+
    Section: 28.9.2 [re.submatch.op] Status: New
+ Submitter: Daniel Krügler Opened: 2009-07-25  Last modified: 2009-07-28
    
+
    View all other issues in [re.submatch.op].
    
 
    View all issues with New status.
    
 
    Discussion:
    
 
    
-This is probably editorial.
+Several heterogeneous comparison operators of class template
+sub_match are specified by return clauses that are not valid
+in general. E.g. 28.9.2 [re.submatch.op]/7:
 
    
+
+
    template <class BiIter, class ST, class SA>
+bool operator==(
+  const basic_string<
+    typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+  const sub_match<BiIter>& rhs);
+
    
+
    
+Returns: lhs == rhs.str().
+
    
+
    
+
 
    
-The following items should be removed from the draft, because they're
-redundant with Annex D, and they arguably make some *.h headers
-non-deprecated:
+The returns clause would be ill-formed for all cases where
+ST != std::char_traits<iterator_traits<BiIter>::value_type>
+or SA != std::allocator<iterator_traits<BiIter>::value_type>.
 
    
 
    
-18.4.2 [stdinth] (regarding <stdint.h>) 
+The generic character of the comparison was intended, so
+there are basically two approaches to fix the problem: The
+first one would define the semantics of the comparison
+using the traits class ST (The semantic of basic_string::compare
+is defined in terms of the compare function of the corresponding
+traits class), the second one would define the semantics of the
+comparison using the traits class
 
    
+
+
    std::char_traits<iterator_traits<BiIter>::value_type>
+
    
+
 
    
-26.3.2 [fenv] (regarding <fenv.h>
+which is essentially identical to
 
    
+
+
    std::char_traits<sub_match<BiIter>::value_type>
+
    
+
 
    
-Line 3 of 26.8 [c.math] (regarding <tgmath.h>) 
+I suggest to follow the second approach, because
+this emphasizes the central role of the sub_match
+object as part of the comparison and would also
+make sure that a sub_match comparison using some
+basic_string<char_t, ..> always is equivalent to
+a corresponding comparison with a string literal
+because of the existence of further overloads (beginning
+from 28.9.2 [re.submatch.op]/19). If users really want to
+take advantage of their own traits::compare, they can
+simply write a corresponding compare function that
+does so.
 
    
+
+
+
    Proposed resolution:
    
+
      
+
    1. 
 
      
-26.4.11 [cmplxh] (regarding <complex.h>, though the note in this subclause is not redundant) 
+In 28.9.2 [re.submatch.op] change as indicated:
 
      
 
-
      [
-2009-06-10 Ganesh adds:
-]
      
+
        
+
      1. 
 
+
        
+If 1180 is accepted:
+
        
 
 
        
-While searching for stdint in the CD, I found that <stdint.h> is also
-mentioned in 3.9.1 [basic.fundamental] /5. It guess it should refer to
-<cstdint> instead.
+
        template <class BiIter, class ST, class SA>
+  bool operator==(
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+    const sub_match<BiIter>& rhs);
+
        
+
        
+7 Returns: lhstypename
+sub_match<BiIter>::string_type(lhs.begin(), lhs.end()) ==
+rhs.str().
 
        
 
+
        template <class BiIter, class ST, class SA>
+  bool operator!=(
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+    const sub_match<BiIter>& rhs);
+
        
 
-
        Proposed resolution:
        
-
        
-Remove the section 18.4.2 [stdinth].
-
        
-
        
-Remove the section 26.3.2 [fenv].
-
        
-
        
-Remove 26.8 [c.math], p3:
-
        
+
        
+8 Returns: lhstypename
+sub_match<BiIter>::string_type(lhs.begin(), lhs.end()) !=
+rhs.str().
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator<(
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+    const sub_match<BiIter>& rhs);
+
        
 
 
        
--3- The header <tgmath.h> effectively includes the headers <complex.h>
-and <math.h>.
+9 Returns: lhstypename
+sub_match<BiIter>::string_type(lhs.begin(), lhs.end()) <
+rhs.str().
 
        
-
        
-Remove the section 26.4.11 [cmplxh].
-
        
 
+
        template <class BiIter, class ST, class SA>
+  bool operator>(
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+    const sub_match<BiIter>& rhs);
+
        
 
+
        
+10 Returns: lhstypename
+sub_match<BiIter>::string_type(lhs.begin(), lhs.end()) >
+rhs.str().
+
        
 
+
        template <class BiIter, class ST, class SA>
+  bool operator>=(
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+    const sub_match<BiIter>& rhs);
+
        
 
+
        
+11 Returns: lhstypename
+sub_match<BiIter>::string_type(lhs.begin(), lhs.end()) >=
+rhs.str().
+
        
 
-
        
-
        1135. exception_ptr should support contextual conversion to bool
        
-
        Section: 18.8.5 [propagation] Status: New
- Submitter: Daniel Krügler Opened: 2007-06-06  Last modified: 2009-06-09
        
-
        View other active issues in [propagation].
        
-
        View all other issues in [propagation].
        
-
        View all issues with New status.
        
-
        Discussion:
        
-
        
-As of
-N2857
-18.8.5 [propagation]/5, the implementation-defined type
-exception_ptr does provide the following ways to check whether
-it is a null value:
-
        
-
        void f(std::exception_ptr p) {
-  p == nullptr;
-  p == 0;
-  p == exception_ptr();
-}
-
        
-
        
-This is rather cumbersome way of checking for the null value
-and I suggest to require support for evaluation in a boolean
-context like so:
-
        
+
        template <class BiIter, class ST, class SA>
+  bool operator<=(
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+    const sub_match<BiIter>& rhs);
+
        
 
-
        void g(std::exception_ptr p) {
-  if (p) {}
-  !p;
-}
-
        
+
        
+12 Returns: lhstypename
+sub_match<BiIter>::string_type(lhs.begin(), lhs.end()) <=
+rhs.str().
+
        
 
+
        template <class BiIter, class ST, class SA>
+  bool operator==(const sub_match<BiIter>& lhs,
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
        
 
-
        Proposed resolution:
        
-
        
-In section 18.8.5 [propagation] insert a new paragraph between p.5 and p.6:
-
        
+
        
+13 Returns: lhs.str() == rhstypename
+sub_match<BiIter>::string_type(rhs.begin(), rhs.end()).
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator!=(const sub_match<BiIter>& lhs,
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
        
 
 
        
-
-An object e of type exception_ptr can be contextually converted to bool.
-The effect shall be as if e != exception_ptr() had been evaluated in place
-of e. There shall be no implicit conversion to arithmetic type, to
-enumeration type or to pointer type.
-
+14 Returns: lhs.str() != rhstypename
+sub_match<BiIter>::string_type(rhs.begin(), rhs.end()).
 
        
 
+
        template <class BiIter, class ST, class SA>
+  bool operator<(const sub_match<BiIter>& lhs,
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
        
 
+
        
+15 Returns: lhs.str() < rhstypename
+sub_match<BiIter>::string_type(rhs.begin(), rhs.end()).
+
        
 
+
        template <class BiIter, class ST, class SA>
+  bool operator>(const sub_match<BiIter>& lhs,
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
        
 
+
        
+16 Returns: lhs.str() > rhstypename
+sub_match<BiIter>::string_type(rhs.begin(), rhs.end()).
+
        
 
-
        
-
        1136. Incomplete specification of nested_exception::rethrow_nested()
        
-
        Section: 18.8.6 [except.nested] Status: New
- Submitter: Daniel Krügler Opened: 2007-06-06  Last modified: 2009-06-09
        
-
        View other active issues in [except.nested].
        
-
        View all other issues in [except.nested].
        
-
        View all issues with New status.
        
-
        Discussion:
        
-
        
-It was recently mentioned in a newsgroup article
-http://groups.google.de/group/comp.std.c++/msg/f82022aff68edf3d
-that the specification of the member function rethrow_nested() of the
-class nested_exception is incomplete, specifically it remains unclear
-what happens, if member nested_ptr() returns a null value. In
-18.8.6 [except.nested] we find only the following paragraph related to that:
-
        
-
        void rethrow_nested() const; // [[noreturn]]
+
        template <class BiIter, class ST, class SA>
+  bool operator>=(const sub_match<BiIter>& lhs,
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
 
        
+
 
        
--4- Throws: the stored exception captured by this nested_exception object.
+17 Returns: lhs.str() >= rhstypename
+sub_match<BiIter>::string_type(rhs.begin(), rhs.end()).
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator<=(const sub_match<BiIter>& lhs,
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
        
+
+
        
+18 Returns: lhs.str() <= rhstypename
+sub_match<BiIter>::string_type(rhs.begin(), rhs.end()).
 
        
 
        
-
        
-This is a problem, because it is possible to create an object of
-nested_exception with exactly such a state, e.g.
-
        
-
        #include <exception>
-#include <iostream>
 
-int main() try {
-  std::nested_exception e; // OK, calls current_exception() and stores it's null value
-  e.rethrow_nested(); // ?
-  std::cout << "A" << std::endl;
-}
-catch(...) {
-  std::cout << "B" << std::endl;
-}
-
        
+
        2. 
+
+
      2. 
+
 
        
-I suggest to follow the proposal of the reporter, namely to invoke
-terminate() if nested_ptr() return a null value of exception_ptr instead
-of relying on the fallback position of undefined behavior. This would
-be consistent to the behavior of a throw; statement when no
-exception is being handled.
+If 1180 is not accepted:
 
        
 
+
        
+
        template <class BiIter, class ST, class SA>
+  bool operator==(
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+    const sub_match<BiIter>& rhs);
+
        
+
        
+7 Returns: lhsbasic_string<typename
+sub_match<BiIter>::value_type>(lhs.begin(), lhs.end()) ==
+rhs.str().
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator!=(
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+    const sub_match<BiIter>& rhs);
+
        
+
+
        
+8 Returns: lhsbasic_string<typename
+sub_match<BiIter>::value_type>(lhs.begin(), lhs.end()) !=
+rhs.str().
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator<(
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+    const sub_match<BiIter>& rhs);
+
        
+
+
        
+9 Returns: lhsbasic_string<typename
+sub_match<BiIter>::value_type>(lhs.begin(), lhs.end()) <
+rhs.str().
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator>(
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+    const sub_match<BiIter>& rhs);
+
        
+
+
        
+10 Returns: lhsbasic_string<typename
+sub_match<BiIter>::value_type>(lhs.begin(), lhs.end()) >
+rhs.str().
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator>=(
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+    const sub_match<BiIter>& rhs);
+
        
+
+
        
+11 Returns: lhsbasic_string<typename
+sub_match<BiIter>::value_type>(lhs.begin(), lhs.end()) >=
+rhs.str().
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator<=(
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+    const sub_match<BiIter>& rhs);
+
        
+
+
        
+12 Returns: lhsbasic_string<typename
+sub_match<BiIter>::value_type>(lhs.begin(), lhs.end()) <=
+rhs.str().
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator==(const sub_match<BiIter>& lhs,
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
        
+
+
        
+13 Returns: lhs.str() == rhsbasic_string<typename
+sub_match<BiIter>::value_type>(rhs.begin(), rhs.end()).
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator!=(const sub_match<BiIter>& lhs,
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
        
+
+
        
+14 Returns: lhs.str() != rhsbasic_string<typename
+sub_match<BiIter>::value_type>(rhs.begin(), rhs.end()).
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator<(const sub_match<BiIter>& lhs,
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
        
+
+
        
+15 Returns: lhs.str() < rhsbasic_string<typename
+sub_match<BiIter>::value_type>(rhs.begin(), rhs.end()).
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator>(const sub_match<BiIter>& lhs,
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
        
+
+
        
+16 Returns: lhs.str() > rhsbasic_string<typename
+sub_match<BiIter>::value_type>(rhs.begin(), rhs.end()).
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator>=(const sub_match<BiIter>& lhs,
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
        
+
+
        
+17 Returns: lhs.str() >= rhsbasic_string<typename
+sub_match<BiIter>::value_type>(rhs.begin(), rhs.end()).
+
        
+
+
        template <class BiIter, class ST, class SA>
+  bool operator<=(const sub_match<BiIter>& lhs,
+    const basic_string<
+      typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
        
 
-
        Proposed resolution:
        
-
        
-Change around 18.8.6 [except.nested]/4 as indicated:
-
        
 
        
-
        
--4- Throws: the stored exception captured by this nested_exception
-object, if nested_ptr() != nullptr
-
        
-
        
-- Remarks: If nested_ptr() == nullptr, terminate()
-shall be called.
-
        
+18 Returns: lhs.str() <= rhsbasic_string<typename
+sub_match<BiIter>::value_type>(rhs.begin(), rhs.end()).
+
        
 
        
 
+
        3. 
+
+
      
+
+
      2. 
+
    
+
 
 
 
 
 
    
-
    1137. Return type of conj and proj
    
-
    Section: 26.4.9 [cmplx.over] Status: New
- Submitter: Marc Steinbach Opened: 2009-06-11  Last modified: 2009-06-14
    
-
    View all other issues in [cmplx.over].
    
+
    1182. Unfortunate hash dependencies
    
+
    Section: 20.7.17 [unord.hash] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-07-28  Last modified: 2009-07-30
    
+
    View other active issues in [unord.hash].
    
+
    View all other issues in [unord.hash].
    
 
    View all issues with New status.
    
 
    Discussion:
    
 
    
-In clause 1, the Working Draft 
-(N2857)
-specifies overloads of the
-functions
+The implied library dependencies created by spelling out all the hash
+template specializations in the <functional> synopsis are unfortunate. 
+The potential coupling is greatly reduced if the hash specialization is
+declared in the appropriate header for each library type, as it is much
+simpler to forward declare the primary template and provide a single
+specialization than it is to implement a hash function for a string or
+vector without providing a definition for the whole string/vector
+template in order to access the necessary bits.
 
    
-
    arg, conj, imag, norm, proj, real
-
    
+
 
    
-for non-complex arithmetic types (float, double,
-long double, and integers).
-The only requirement (clause 2) specifies type promotion of arguments.
+Note that the proposed resolution purely involves moving the
+declarations of a few specializations, it specifically does not make any
+changes to 20.7.17 [unord.hash].
 
    
+
+
+
    Proposed resolution:
    
 
    
-I strongly suggest to add the following requirement on the return types:
+Strike the following specializations declared in the <functional>
+synopsis p2 20.7 [function.objects]
 
    
-
    
-All the specified overloads must return real (i.e., non-complex) values,
-specifically, the nested value_type of promoted arguments.
-
    
+
+
    template <> struct hash<std::string>;
+template <> struct hash<std::u16string>;
+template <> struct hash<std::u32string>;
+template <> struct hash<std::wstring>;
+
+template <class Allocator> struct hash<std::vector<bool, Allocator> >;
+template <std::size_t N> struct hash<std::bitset<N> >;
+
    
 
 
    
-(This has no effect on arg, imag, norm, real:
-they are real-valued anyway.)
+Add the following declarations to the synopsis of <string> in
+21.3 [string.classes]
 
    
-
    Rationale:
    
+
+
    // 21.4.x hash support
+template <class T> struct hash;
+template <> struct hash<string>;
+template <> struct hash<u16string>;
+template <> struct hash<u32string>;
+template <> struct hash<wstring>;
+
    
+
 
    
-Mathematically, conj() and proj(), like the transcendental functions, are
-complex-valued in general but map the (extended) real line to itself.
-In fact, both functions act as identity on the reals.
-A typical user will expect conj() and proj() to preserve this essential
-mathematical property in the same way as exp(), sin(), etc.
-A typical use of conj(), e.g., is the generic scalar product of n-vectors:
+Add a new clause 21.4.X
 
    
 
-
    template<typename T>
-inline T
-scalar_product(size_t n, T const* x, T const* y) {
-  T result = 0;
-  for (size_t i = 0; i < n; ++i)
-    result += std::conj(x[i]) * y[i];
-  return result;
-}
-
    
+
    
 
    
-This will work equally well for real and complex floating-point types T if
-conj() returns T. It will not work with real types if conj()
-returns complex values.
+21.4.X Hash support [basic.string.hash]
 
    
+
+
    template <> struct hash<string>;
+template <> struct hash<u16string>;
+template <> struct hash<u32string>;
+template <> struct hash<wstring>;
+
    
+
+
    
+Explicit specializations of the class template hash (20.7.17 [unord.hash])
+shall be provided for the types string, u16string,
+u32string and wstring suitable for using these types as keys in
+unordered associative containers (23.5 [unord]).
+
    
+
    
+
 
    
-Instead, the implementation of scalar_product becomes either less efficient
-and less useful (if a complex result is always returned), or unnecessarily
-complicated (if overloaded versions with proper return types are defined).
-In the second case, conj() is not used with real arguments.
+Add the following declarations to the synopsis of <vector> in 
+23.3 [sequences]
 
    
+
+
    
+// 21.4.x hash support
+template <class T> struct hash;
+template <class Allocator> struct hash<vector<bool, Allocator>>;
+
    
+
 
    
-Any use of conj() I can think of would benefit from the proposed return type
-requirement, in a similar way.
-It will not harm use cases where a complex value is expected, because of
-implicit conversion to complex.
-Without the proposed return type guarantee, I find an overloaded conj() not
-only useless but actually troublesome.
+Add a new paragraph to the end of 23.3.7 [vector.bool]
 
    
+
+
    template <class Allocator> struct hash<vector<bool, Allocator>>;
+
    
+
    
+A partial specialization of the class template hash (20.7.17 [unord.hash])
+shall be provided for vectors of boolean values suitable for use as a key
+in unordered associative containers (23.5 [unord]).
+
    
+
    
+
 
    
-I believe that the same applies to proj(), althought up to now I had no need
-for it.
+Add the following declarations to the synopsis of <bitset>
+in 20.3.6 [template.bitset]
 
    
 
+
    
+// 20.3.6.X hash support
+template <class T> struct hash;
+template <size_t N> struct hash<bitset<N> >;
+
    
 
+
    
+Add a new subclause 20.3.6.X [bitset.hash]
+
    
 
-
    Proposed resolution:
    
+
    
 
    
-Insert a new paragraph after 26.4.9 [cmplx.over]/2:
+20.3.6.X bitset hash support [bitset.hash]
 
    
 
+
    template <size_t N> struct hash<bitset<N> >;
+
    
+
 
    
-
-All of the specified overloads shall have a return type which is the nested value_type of
-the promoted arguments.
-
+A partial specialization of the class template hash
+(20.7.17 [unord.hash]) shall be provided for bitsets suitable for use as a key in
+unordered associative containers (23.5 [unord]).
+
    
 
    
 
 
 
 
 
+
 
    
-
    1138. unusal return value for operator+
    
-
    Section: 21.4.8.1 [string::op+] Status: New
- Submitter: Alisdair Meredith Opened: 2009-06-12  Last modified: 2009-06-15
    
+
    1183. basic_ios::set_rdbuf may break class invariants
    
+
    Section: 27.5.4.2 [basic.ios.members] Status: New
+ Submitter: Daniel Krügler Opened: 2009-07-28  Last modified: 2009-07-28
    
+
    View other active issues in [basic.ios.members].
    
+
    View all other issues in [basic.ios.members].
    
 
    View all issues with New status.
    
 
    Discussion:
    
 
    
-Many of the basic_string operator+ overloads return an rvalue-reference.  Is
-that really intended?
+The protected member function set_rdbuf had been added during the
+process of adding move and swap semantics to IO classes. A relevant
+property of this function is described by it's effects in
+27.5.4.2 [basic.ios.members]/19:
 
    
+
+
    
+Effects: Associates the basic_streambuf object pointed to by sb with
+this stream without calling clear().
+
    
+
 
    
-I'm considering it might be a mild performance tweak to avoid making
-un-necessary copies of a cheaply movable type, but it opens risk to dangling
-references in code like:
+This means that implementors of or those who derive from existing IO classes
+could cause an internal state where the stream buffer could be 0, but the
+IO class has the state good(). This would break several currently existing
+implementations which rely on the fact that setting a stream buffer via the
+currently only ways, i.e. either by calling
 
    
 
-
    auto && s = string{"x"} + string{y};
+
    void init(basic_streambuf<charT,traits>* sb);
 
    
 
 
    
-and I'm not sure about:
+or by calling
 
    
 
-
    auto s = string{"x"} + string{y};
+
    basic_streambuf<charT,traits>* rdbuf(basic_streambuf<charT,traits>* sb);
 
    
 
-
-
    Proposed resolution:
    
 
    
-Strike the && from the return type in the following function
-signatures:
+to set rdstate() to badbit, if the buffer is 0. This has the effect that many
+internal functions can simply check rdstate() instead of rdbuf() for being 0.
 
    
 
-
    
 
    
-21.3 [string.classes] p2 Header Synopsis
+I therefore suggest that a requirement is added for callers of set_rdbuf to
+set a non-0 value.
 
    
 
-
    template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(basic_string<charT,traits,Allocator>&& lhs,
-              const basic_string<charT,traits,Allocator>& rhs);
-
-template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(const basic_string<charT,traits,Allocator>& lhs,
-              basic_string<charT,traits,Allocator>&& rhs);
-
-template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(basic_string<charT,traits,Allocator>&& lhs,
-              basic_string<charT,traits,Allocator>&& rhs);
-
-
-template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(const charT* lhs,
-              basic_string<charT,traits,Allocator>&& rhs);
-
-template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(charT lhs, basic_string<charT,traits,Allocator>&& rhs);
-
-template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(basic_string<charT,traits,Allocator>&& lhs,
-              const charT* rhs);
-
-template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(basic_string<charT,traits,Allocator>&& lhs, charT rhs);
-
    
 
+
    Proposed resolution:
    
 
    
-21.4.8.1 [string::op+]
+Change 27.5.4.2 [basic.ios.members] around p. 19 as indicated (The proposed
+resolution fixes also two editorial problems: Some wrong letters in "clear()"
+and moving the post conditions into a separate paragraph):
 
    
 
-
    template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(basic_string<charT,traits,Allocator>&& lhs,
-              const basic_string<charT,traits,Allocator>& rhs);
-
-template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(const basic_string<charT,traits,Allocator>& lhs,
-              basic_string<charT,traits,Allocator>&& rhs);
-
-template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(basic_string<charT,traits,Allocator>&& lhs,
-              basic_string<charT,traits,Allocator>&& rhs);
-
+
    void set_rdbuf(basic_streambuf<charT, traits>* sb);
+
    
 
-template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(const charT* lhs,
-              basic_string<charT,traits,Allocator>&& rhs);
+
    
+
    
+Requires: sb != nullptr.
+
    
 
-template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(charT lhs, basic_string<charT,traits,Allocator>&& rhs);
+
    
+Effects: Associates the basic_streambuf object pointed to by sb with
+this stream without
+calling clear(). Postconditions: rdbuf() == sb.
+
    
 
-template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(basic_string<charT,traits,Allocator>&& lhs,
-              const charT* rhs);
+
    
+Postconditions: rdbuf() == sb.
+
    
 
-template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator>&&
-    operator+(basic_string<charT,traits,Allocator>&& lhs, charT rhs);
-
    
+
    
+Throws: Nothing.
+
    
 
 
    
-
+
    
 
 
 
 
 
 
    
-
    1139. Response to US 93
    
-
    Section: 30 [thread] Status: New
- Submitter: Beman Dawes Opened: 2009-06-15  Last modified: 2009-06-15
    
-
    View other active issues in [thread].
    
-
    View all other issues in [thread].
    
+
    1184. Feature request: dynamic bitset
    
+
    Section: 23.3.6 [vector] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-07-29  Last modified: 2009-07-29
    
+
    View other active issues in [vector].
    
+
    View all other issues in [vector].
    
 
    View all issues with New status.
    
 
    Discussion:
    
-
-
    Addresses US 93, JP 79, UK 333, JP 81
    
-
 
    
-The thread chapter is not concept enabled.
+Opened at Alisdair's request, steming from 96.
+Alisdair recommends NAD Future.
 
    
 
 
-
 
    Proposed resolution:
    
 
 
@@ -37778,72 +31984,55 @@ The thread chapter is not concept enabled.
 
 
 
    
-
    1140. Response to US 84
    
-
    Section: 26 [numerics] Status: New
- Submitter: Beman Dawes Opened: 2009-06-15  Last modified: 2009-06-15
    
-
    View other active issues in [numerics].
    
-
    View all other issues in [numerics].
    
+
    1185. iterator categories and output iterators
    
+
    Section: X [iterator.requirements] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-07-31  Last modified: 2009-07-31
    
 
    View all issues with New status.
    
 
    Discussion:
    
-
-
    Addresses US 84
    
-
 
    
-The numerics chapter is not concept enabled.
+(wording relative to
+N2723
+pending new working paper)
 
    
 
 
    
-The portion of this comment dealing with random numbers was resolved by
-N2836,
-which was accepted in Summit.
+According to p3 X [iterator.requirements], Forward iterators,
+Bidirectional iterators and Random Access iterators all satisfy the
+requirements for an Output iterator:
 
    
 
-
-
-
    Proposed resolution:
    
-
-
-
-
-
-
    
-
    1141. Response to US 85
    
-
    Section: 27 [input.output] Status: New
- Submitter: Beman Dawes Opened: 2009-06-15  Last modified: 2009-06-15
    
-
    View other active issues in [input.output].
    
-
    View all other issues in [input.output].
    
-
    View all issues with New status.
    
-
    Discussion:
    
-
-
    Addresses US 85, JP 67, JP 68, JP 69, JP 72
    
+
    
+XXX iterators satisfy all the requirements of the input and output iterators
+and can be used whenever either kind is specified ...
+
    
 
 
    
-The input/output chapter is not concept enabled.
+Meanwhile, p4 goes on to contradict this:
 
    
 
+
    
+Besides its category, a forward, bidirectional, or random access
+iterator can also be mutable or constant...
+
    
 
-
-
    Proposed resolution:
    
-
-
-
-
-
-
    
-
    1142. Response to US 86
    
-
    Section: 28 [re] Status: New
- Submitter: Beman Dawes Opened: 2009-06-15  Last modified: 2009-06-15
    
-
    View other active issues in [re].
    
-
    View all other issues in [re].
    
-
    View all issues with New status.
    
-
    Discussion:
    
-
-
    Addresses US 86, UK 309, UK 310
    
+
    
+... Constant iterators do not satisfy the requirements for output iterators
+
    
 
 
    
-The regular expressions chapter is not concept enabled.
+The latter seems to be the overriding concern, as the iterator tag
+hierarchy does not define forward_iterator_tag as multiply derived from
+both input_iterator_tag and output_iterator_tag.
 
    
 
+
    
+The work on concepts for iterators showed us that output iterator really
+is fundamentally a second dimension to the iterator categories, rather
+than part of the linear input -> forward -> bidirectional ->
+random-access sequence.  It would be good to clear up these words to
+reflect that, and separately list output iterator requirements in the
+requires clauses for the appropriate algorithms and operations.
+
    
 
 
 
    Proposed resolution:
    
@@ -37853,24 +32042,34 @@ The regular expressions chapter is not concept enabled.
 
 
 
    
-
    1143. Response to US 87
    
-
    Section: 29 [atomics] Status: New
- Submitter: Beman Dawes Opened: 2009-06-15  Last modified: 2009-06-15
    
-
    View other active issues in [atomics].
    
-
    View all other issues in [atomics].
    
+
    1186. Forward list could model a stack
    
+
    Section: 23.3.5.3 [stack] Status: New
+ Submitter: Alisdair Meredith Opened: 2009-07-31  Last modified: 2009-08-01
    
 
    View all issues with New status.
    
 
    Discussion:
    
-
-
    Addresses US 87, UK 311
    
-
 
    
-The atomics chapter is not concept enabled.
+The library template forward_list could easily model the idea of a
+stack, where the operations work on the front of the list rather than
+the back.  However, the standard library stack adaptor cannot support
+this.
 
    
 
 
    
-Needs to also consider issues 923 and 924.
+It would be relatively easy to write a partial specialization for stack
+to support forward_list, but that opens the question of which header to
+place it in.  A much better solution would be to add a concept_map for
+the StackLikeContainer concept to the <forward_list> header and then
+everything just works, including a user's own further uses in a
+stack-like context.
 
    
 
+
    
+Therefore while I am submitting the issue now so that it is on record, I
+strongly recommend we resolve as "NAD Concepts" as any non-concepts
+based solution will be inferior to the final goal, and the feature is
+not so compelling it must be supported ahead of the concepts-based
+library.
+
    
 
 
 
    Proposed resolution:
    
diff --git a/libstdc++-v3/doc/html/ext/lwg-closed.html b/libstdc++-v3/doc/html/ext/lwg-closed.html
index e19189d..ce7faf5 100644
--- a/libstdc++-v3/doc/html/ext/lwg-closed.html
+++ b/libstdc++-v3/doc/html/ext/lwg-closed.html
@@ -14,11 +14,11 @@ del {background-color:#FFA0A0}
 
-
+
-
+
@@ -29,7 +29,7 @@ del {background-color:#FFA0A0}
 
    
 
    
 Doc. no.N2896=09-0086N2942=09-0132
 
    
 
    
 Date:2009-06-212009-08-02
 
    
 
    
 Project:Howard Hinnant <howard.hinnant@gmail.com>
 
    
 
    
-
    C++ Standard Library Closed Issues List (Revision R65)
    
+
    C++ Standard Library Closed Issues List (Revision R66)
    
 
   
    Reference ISO/IEC IS 14882:2003(E)
    
   
    Also see:
    
@@ -51,6 +51,58 @@ del {background-color:#FFA0A0}
 
 
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+
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 2005-10-14 post-Mont Tremblant mailing.
 Added new issues 526-528.
 Moved issues 280, 461, 464, 465, 467, 468, 474, 496 from Ready to WP as per the vote from Mont Tremblant.
-Moved issues 247, 294, 342, 362, 369, 371, 376, 384, 475, 478, 495, 497 from Review to Ready.
+Moved issues 247, 294, 342, 362, 369, 371, 376, 384, 475, 478, 495, 497 from Review to Ready.
 Moved issues 498, 504, 506, 509, 510, 511, 512, 513, 514 from New to Open.
 Moved issues 505, 507, 508, 519 from New to Ready.
 Moved issue 500 from New to NAD.
@@ -583,11 +635,11 @@ Moved issue 504-522.
-Added new issues 523-523
+Added new issues 523-523
 
 
  • R37: 
 2005-06 mid-term mailing.
-Added new issues 498-503.
+Added new issues 498-503.
 
    • 
 
  • R36: 
 2005-04 post-Lillehammer mailing. All issues in "ready" status except
@@ -644,7 +696,7 @@ at the meeting.)  Made progress on issues 226 involve wording.
 
    • 
 
  • R23: 
-Pre-Santa Cruz mailing.  Added new issues 367-382.
+Pre-Santa Cruz mailing.  Added new issues 367-382.
 Moved issues in the TC to TC status.
 
    • 
 
  • R22: 
@@ -698,7 +750,7 @@ Changed status of issues
 to Ready.
 
 Closed issues 
-111 277 279 287
+111 277 279 287
 289 293 302 313
 314
 as NAD.
@@ -761,7 +813,7 @@ of issue 83,
 86, 91, 92,
-109. Added issues 190 to
+109. Added issues 190 to
 195. (99-0033/D1209, 14 Oct 99)
 
    • 
 
  • R9: 
@@ -777,10 +829,10 @@ in Dublin. (99-0016/N1193, 21 Apr 99)
 pre-Dublin updated: Added issues 130, 131,
 132, 133, 134,
 135, 136, 137,
-138, 139 (31 Mar 99)
+138, 139 (31 Mar 99)
 
    • 
 
  • R6: 
-pre-Dublin mailing. Added issues 127, 128,
+pre-Dublin mailing. Added issues 127, 128,
 and 129.  (99-0007/N1194, 22 Feb 99)
 
    • 
 
  • R5: 
@@ -790,7 +842,7 @@ for making list public. (30 Dec 98)
 
    • 
 
  • R4: 
 post-Santa Cruz II updated: Issues 110,
-111, 112, 113 added, several
+111, 112, 113 added, several
 issues corrected. (22 Oct 98)
 
    • 
 
  • R3: 
@@ -838,7 +890,6 @@ exists.)
    
 
    4. Basic_string size_type and difference_type should be implementation defined
    
 
    Section: 21.4 [basic.string] Status: NAD
  Submitter: Beman Dawes Opened: 1997-11-16  Last modified: 2006-12-27
    
-
    View other active issues in [basic.string].
    
 
    View all other issues in [basic.string].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -1081,7 +1132,6 @@ parameters whatsoever.
    
 
    72. Do_convert phantom member function
    
 
    Section: 22.4.1.4 [locale.codecvt] Status: Dup
  Submitter: Nathan Myers Opened: 1998-08-24  Last modified: 2006-12-30
    
-
    View other active issues in [locale.codecvt].
    
 
    View all other issues in [locale.codecvt].
    
 
    View all issues with Dup status.
    
 
    Duplicate of: 24
    
@@ -1188,7 +1238,6 @@ otherwise possible. 
    
 
    82. Missing constant for set elements
    
 
    Section: 23.2.4 [associative.reqmts] Status: NAD
  Submitter: Nico Josuttis Opened: 1998-09-29  Last modified: 2007-01-15
    
-
    View other active issues in [associative.reqmts].
    
 
    View all other issues in [associative.reqmts].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -1570,6 +1619,7 @@ incorrect code to work, rather than the other way around.
    
 
    101. No way to free storage for vector and deque
    
 
    Section: 23.3.6 [vector], 23.3.1 [array] Status: NAD
  Submitter: AFNOR Opened: 1998-10-07  Last modified: 2007-02-19
    
+
    View other active issues in [vector].
    
 
    View all other issues in [vector].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -1596,7 +1646,6 @@ expressed in a single line of code (where v is
 
    102. Bug in insert range in associative containers
    
 
    Section: 23.2.4 [associative.reqmts] Status: Dup
  Submitter: AFNOR Opened: 1998-10-07  Last modified: 2006-12-30
    
-
    View other active issues in [associative.reqmts].
    
 
    View all other issues in [associative.reqmts].
    
 
    View all issues with Dup status.
    
 
    Duplicate of: 264
    
@@ -1694,6 +1743,98 @@ perhaps other cases.
    
 
 
 
    
+
    111. istreambuf_iterator::equal overspecified, inefficient
    
+
    Section: 24.6.3.5 [istreambuf.iterator::equal] Status: NAD
+ Submitter: Nathan Myers Opened: 1998-10-15  Last modified: 2009-07-14
    
+
    View all other issues in [istreambuf.iterator::equal].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    The member istreambuf_iterator<>::equal is specified to be
+unnecessarily inefficient. While this does not affect the efficiency
+of conforming implementations of iostreams, because they can
+"reach into" the iterators and bypass this function, it does
+affect users who use istreambuf_iterators. 
    
+
+
    The inefficiency results from a too-scrupulous definition, which
+requires a "true" result if neither iterator is at eof. In
+practice these iterators can only usefully be compared with the
+"eof" value, so the extra test implied provides no benefit,
+but slows down users' code. 
    
+
+
    The solution is to weaken the requirement on the function to return
+true only if both iterators are at eof. 
    
+
+
    [
+Summit:
+]
    
+
+
+
    
+Reopened by Alisdair.
+
    
+
+
    [
+Post Summit Daniel adds:
+]
    
+
+
+
    
+
    
+Recommend NAD. The proposed wording would violate the axioms of
+concept requirement EqualityComparable axioms as part of concept InputIterator
+and more specifically it would violate the explicit wording of
+24.2.2 [input.iterators]/7:
+
    
+
+
    
+If two iterators a and b of the same type are equal, then either a
+and b are both
+dereferenceable or else neither is dereferenceable.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+Agree NAD.
+
    
+
+
    
+
+
+
+
    Proposed resolution:
    
+
    Replace 24.6.3.5 [istreambuf.iterator::equal],
+paragraph 1, 
    
+
+
    
+  
    -1- Returns: true if and only if both iterators are at end-of-stream, or neither is at
+  end-of-stream, regardless of what streambuf object they use. 
    
+
    
+
+
    with
    
+
+
    
+  
    -1- Returns: true if and only if both iterators are at
+  end-of-stream, regardless of what streambuf object they use. 
    
+
    
+
+
+
+
    Rationale:
    
+
    It is not clear that this is a genuine defect.  Additionally, the
+LWG was reluctant to make a change that would result in 
+operator== not being a equivalence relation.  One consequence of
+this change is that an algorithm that's passed the range [i, i)
+would no longer treat it as an empty range.
    
+
+
+
+
+
+
    
 
    113. Missing/extra iostream sync semantics
    
 
    Section: 27.7.1.1 [istream], 27.7.1.3 [istream.unformatted] Status: NAD
  Submitter: Steve Clamage Opened: 1998-10-13  Last modified: 2006-12-27
    
@@ -1841,6 +1982,81 @@ ctype<wchar_t> specialization. 
    
 
 
 
    
+
    128. Need open_mode() function for file stream, string streams, file buffers, and string  buffers
    
+
    Section: 27.8 [string.streams], 27.9 [file.streams] Status: NAD
+ Submitter: Angelika Langer Opened: 1999-02-22  Last modified: 2009-07-14
    
+
    View all other issues in [string.streams].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    The following question came from Thorsten Herlemann:
    
+
+
    
+  
    You can set a mode when constructing or opening a file-stream or
+  filebuf, e.g.  ios::in, ios::out, ios::binary, ... But how can I get
+  that mode later on, e.g. in my own operator << or operator
+  >> or when I want to check whether a file-stream or
+  file-buffer object passed as parameter is opened for input or output
+  or binary? Is there no possibility? Is this a design-error in the
+  standard C++ library? 
    
+
    
+
+
    It is indeed impossible to find out what a stream's or stream
+buffer's open mode is, and without that knowledge you don't know
+how certain operations behave. Just think of the append mode. 
    
+
+
    Both streams and stream buffers should have a mode() function that returns the
+current open mode setting. 
    
+
+
    [
+post Bellevue:  Alisdair requested to re-Open.
+]
    
+
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+Neither Howard nor Bill has received a customer request for this.
+
    
+
    
+No consensus for change. The programmer can save this information to the side.
+
    
+
    
+Moved to NAD.
+
    
+
    
+
+
+
+
    Proposed resolution:
    
+
    For stream buffers, add a function to the base class as a non-virtual function
+qualified as const to 27.6.2 [streambuf]:
    
+
+
        openmode mode() const;
    
+
+
        Returns the current open mode.
    
+
+
    With streams, I'm not sure what to suggest. In principle, the mode
+could already be returned by ios_base, but the mode is only
+initialized for file and string stream objects, unless I'm overlooking
+anything. For this reason it should be added to the most derived
+stream classes. Alternatively, it could be added to basic_ios
+and would be default initialized in basic_ios<>::init().
    
+
+
+
    Rationale:
    
+
    This might be an interesting extension for some future, but it is
+not a defect in the current standard. The Proposed Resolution is
+retained for future reference.
    
+
+
+
+
+
+
    
 
    131. list::splice throws nothing
    
 
    Section: 23.3.4.4 [list.ops] Status: NAD
  Submitter: Howard Hinnant Opened: 1999-03-06  Last modified: 2007-02-19
    
@@ -1891,6 +2107,62 @@ standard.
    
 
 
 
    
+
    138. Class ctype_byname<char> redundant and misleading
    
+
    Section: 22.4.1.4 [locale.codecvt] Status: NAD
+ Submitter: Angelika Langer Opened: 1999-03-18  Last modified: 2009-07-14
    
+
    View all other issues in [locale.codecvt].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    Section 22.4.1.4 [locale.codecvt] specifies that
+ctype_byname<char> must be a specialization of the ctype_byname
+template.
    
+
+
    It is common practice in the standard that specializations of class templates are only
+mentioned where the interface of the specialization deviates from the interface of the
+template that it is a specialization of. Otherwise, the fact whether or not a required
+instantiation is an actual instantiation or a specialization is left open as an
+implementation detail. 
    
+
+
    Clause 22.2.1.4 deviates from that practice and for that reason is misleading. The
+fact, that ctype_byname<char> is specified as a specialization suggests that there
+must be something "special" about it, but it has the exact same interface as the
+ctype_byname template. Clause 22.2.1.4 does not have any explanatory value, is at best
+redundant, at worst misleading - unless I am missing anything. 
    
+
+
    Naturally, an implementation will most likely implement ctype_byname<char> as a
+specialization, because the base class ctype<char> is a specialization with an
+interface different from the ctype template, but that's an implementation detail and need
+not be mentioned in the standard. 
    
+
+
    [
+Summit:
+]
    
+
+
+
    
+Reopened by Alisdair.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+Moved to NAD.
+
    
+
+
+
+
    Rationale:
    
+
     The standard as written is mildly misleading, but the correct fix
+is to deal with the underlying problem in the ctype_byname base class,
+not in the specialization. See issue 228.
    
+
+
+
+
+
    
 
    140. map<Key, T>::value_type does not satisfy the assignable requirement
    
 
    Section: 23.4.1 [map] Status: NAD Editorial
  Submitter: Mark Mitchell Opened: 1999-04-14  Last modified: 2008-03-14
    
@@ -2317,6 +2589,50 @@ operators.
    
 
 
 
    
+
    190. min() and max() functions should be std::binary_functions
    
+
    Section: 25.5.7 [alg.min.max] Status: NAD
+ Submitter: Mark Rintoul Opened: 1999-08-26  Last modified: 2009-07-14
    
+
    View all other issues in [alg.min.max].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    Both std::min and std::max are defined as template functions.  This
+is very different than the definition of std::plus (and similar
+structs) which are defined as function objects which inherit
+std::binary_function.
    
+
    
+        This lack of inheritance leaves std::min and std::max somewhat useless in standard library algorithms which require
+a function object that inherits std::binary_function.
    
+
+
    [
+post Bellevue:  Alisdair requested to re-Open.
+]
    
+
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+C++0x has lambdas to address this problem now.
+
    
+
    
+Moved to NAD.
+
    
+
    
+
+
+
+
    Rationale:
    
+
    Although perhaps an unfortunate design decision, the omission is not a defect
+in the current standard.  A future standard may wish to consider additional
+function objects.
    
+
+
+
+
+
    
 
    191. Unclear complexity for algorithms such as binary search
    
 
    Section: 25.5.3 [alg.binary.search] Status: NAD
  Submitter: Nico Josuttis Opened: 1999-10-10  Last modified: 2006-12-27
    
@@ -2349,7 +2665,6 @@ iterators.
    
 
    192. a.insert(p,t) is inefficient and overconstrained
    
 
    Section: 23.2.4 [associative.reqmts] Status: NAD
  Submitter: Ed Brey Opened: 1999-06-06  Last modified: 2006-12-30
    
-
    View other active issues in [associative.reqmts].
    
 
    View all other issues in [associative.reqmts].
    
 
    View all issues with NAD status.
    
 
    Duplicate of: 233
    
@@ -2782,7 +3097,6 @@ or write floating point expressions as arguments.
    
 
    215. Can a map's key_type be const?
    
 
    Section: 23.2.4 [associative.reqmts] Status: NAD
  Submitter: Judy Ward Opened: 2000-02-29  Last modified: 2006-12-27
    
-
    View other active issues in [associative.reqmts].
    
 
    View all other issues in [associative.reqmts].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -2899,6 +3213,77 @@ operator<.
    
 
 
 
    
+
    219. find algorithm missing version that takes a binary predicate argument
    
+
    Section: 25.3.5 [alg.find] Status: NAD
+ Submitter: Pablo Halpern Opened: 2000-03-06  Last modified: 2009-07-14
    
+
    View all other issues in [alg.find].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    The find function always searches for a value using operator== to compare the
+value argument to each element in the input iterator range. This is inconsistent
+with other find-related functions such as find_end and find_first_of, which
+allow the caller to specify a binary predicate object to be used for determining
+equality. The fact that this can be accomplished using a combination of find_if
+and bind_1st or bind_2nd does not negate the desirability of a consistent,
+simple, alternative interface to find.
    
+
+
    [
+Summit:
+]
    
+
+
+
    
+Reopened by Alisdair.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+The same thing can be achieved using find_if (as noted in the issue).
+
    
+
    
+Moved to NAD.
+
    
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+
    In section 25.3.5 [alg.find], add a second prototype for find
+(between the existing prototype and the prototype for find_if), as
+follows:
    
+
        template<class InputIterator, class T, class BinaryPredicate>
+      InputIterator find(InputIterator first, InputIterator last,
+                         const T& value, BinaryPredicate bin_pred);
    
+
    Change the description of the return from:
    
+
    
+  
    Returns: The first iterator i in the range [first, last) for which the following corresponding
+  conditions hold: *i == value, pred(*i) != false. Returns last if no such iterator is found.
    
+
    
+
     to:
    
+
    
+  
    Returns: The first iterator i in the range [first, last) for which the following 
+  corresponding condition holds: *i == value, bin_pred(*i,value) != false, pred(*)
+  != false. Return last if no such iterator is found.
    
+
    
+
    
+
+
+
    Rationale:
    
+
    This is request for a pure extension, so it is not a defect in the
+current standard.  As the submitter pointed out, "this can
+be accomplished using a combination of find_if and bind_1st or
+bind_2nd".
    
+
+
+
+
+
    
 
    236. ctype<char>::is() member modifies facet
    
 
    Section: 22.4.1.3.2 [facet.ctype.char.members] Status: Dup
  Submitter: Dietmar Kühl Opened: 2000-04-24  Last modified: 2007-01-15
    
@@ -3011,7 +3396,6 @@ how many times find may invoke operator++.
    
 
    246. a.insert(p,t) is incorrectly specified
    
 
    Section: 23.2.4 [associative.reqmts] Status: Dup
  Submitter: Mark Rodgers Opened: 2000-05-19  Last modified: 2007-01-15
    
-
    View other active issues in [associative.reqmts].
    
 
    View all other issues in [associative.reqmts].
    
 
    View all issues with Dup status.
    
 
    Duplicate of: 233
    
@@ -3100,7 +3484,6 @@ Change the words "right after" to "immediately before".
    
 
    249. Return Type of auto_ptr::operator=
    
 
    Section: D.9.1 [auto.ptr] Status: NAD
  Submitter: Joseph Gottman Opened: 2000-06-30  Last modified: 2006-12-29
    
-
    View other active issues in [auto.ptr].
    
 
    View all other issues in [auto.ptr].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -3140,6 +3523,111 @@ code.
    
 
 
 
    
+
    255. Why do basic_streambuf<>::pbump() and gbump() take an int?
    
+
    Section: 27.6.2 [streambuf] Status: NAD Future
+ Submitter: Martin Sebor Opened: 2000-08-12  Last modified: 2009-07-14
    
+
    View all other issues in [streambuf].
    
+
    View all issues with NAD Future status.
    
+
    Discussion:
    
+
    
+The basic_streambuf members gbump() and pbump() are specified to take an
+int argument. This requirement prevents the functions from effectively
+manipulating buffers larger than std::numeric_limits<int>::max()
+characters. It also makes the common use case for these functions
+somewhat difficult as many compilers will issue a warning when an
+argument of type larger than int (such as ptrdiff_t on LLP64
+architectures) is passed to either of the function. Since it's often the
+result of the subtraction of two pointers that is passed to the
+functions, a cast is necessary to silence such warnings. Finally, the
+usage of a native type in the functions signatures is inconsistent with
+other member functions (such as sgetn() and sputn()) that manipulate the
+underlying character buffer. Those functions take a streamsize argument.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+This is part of a bigger problem. If anyone cares enough, they should
+write a paper solving the bigger problem of offset types in iostreams.
+
    
+
    
+This is related to the paper about large file sizes. Beman has already
+agreed to drop the section of that paper that deals with this.
+
    
+
    
+int is big enough for reasonable buffers.
+
    
+
    
+Move to NAD Future.
+
    
+
    
+This is related to LWG 423.
+
    
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+Change the signatures of these functions in the synopsis of template
+class basic_streambuf (27.5.2) and in their descriptions (27.5.2.3.1, p4
+and 27.5.2.3.2, p4) to take a streamsize argument.
+
    
+
+
    
+Although this change has the potential of changing the ABI of the
+library, the change will affect only platforms where int is different
+than the definition of streamsize. However, since both functions are
+typically inline (they are on all known implementations), even on such
+platforms the change will not affect any user code unless it explicitly
+relies on the existing type of the functions (e.g., by taking their
+address). Such a possibility is IMO quite remote.
+
    
+
+
    
+Alternate Suggestion from Howard Hinnant, c++std-lib-7780:
+
    
+
+
    
+This is something of a nit, but I'm wondering if streamoff wouldn't be a 
+better choice than streamsize.  The argument to pbump and gbump MUST be 
+signed.  But the standard has this to say about streamsize 
+(27.4.1/2/Footnote):
+
    
+
+
    
+     [Footnote: streamsize is used in most places where ISO C would use
+     size_t.  Most of the uses of streamsize could use size_t, except for
+     the strstreambuf constructors, which require negative values. It
+     should probably be the signed type corresponding to size_t (which is
+     what Posix.2 calls ssize_t). --- end footnote]
+
    
+
+
    
+This seems a little weak for the argument to pbump and gbump.  Should we 
+ever really get rid of strstream, this footnote might go with it, along 
+with the reason to make streamsize signed.
+
    
+
+
+
    Rationale:
    
+
    The LWG believes this change is too big for now.  We may wish to
+reconsider this for a future revision of the standard.  One
+possibility is overloading pbump, rather than changing the
+signature.
    
+
    [
+[2006-05-04: Reopened at the request of Chris (Krzysztof ?elechowski)]
+]
    
+
+
+
+
+
+
    
 
    257. STL functional object and iterator inheritance.
    
 
    Section: 20.7.3 [base], D.10.2 [iterator.basic] Status: NAD
  Submitter: Robert Dick  Opened: 2000-08-17  Last modified: 2006-12-29
    
@@ -3634,10 +4122,73 @@ never referred to by the C++ standard.
    
 
 
 
    
-
    293. Order of execution in transform algorithm
    
-
    Section: 25.4.4 [alg.transform] Status: NAD
- Submitter: Angelika Langer Opened: 2001-01-04  Last modified: 2007-01-15
    
-
    View all other issues in [alg.transform].
    
+
    290. Requirements to for_each and its function object
    
+
    Section: 25.3.4 [alg.foreach] Status: NAD
+ Submitter: Angelika Langer Opened: 2001-01-03  Last modified: 2009-07-14
    
+
    View all other issues in [alg.foreach].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    The specification of the for_each algorithm does not have a
+"Requires" section, which means that there are no
+restrictions imposed on the function object whatsoever. In essence it
+means that I can provide any function object with arbitrary side
+effects and I can still expect a predictable result. In particular I
+can expect that the function object is applied exactly last - first
+times, which is promised in the "Complexity" section.
+
    
+
+
    I don't see how any implementation can give such a guarantee
+without imposing requirements on the function object.
+
    
+
+
    Just as an example: consider a function object that removes
+elements from the input sequence.  In that case, what does the
+complexity guarantee (applies f exactly last - first times) mean?
+
    
+
+
    One can argue that this is obviously a nonsensical application and
+a theoretical case, which unfortunately it isn't.  I have seen
+programmers shooting themselves in the foot this way, and they did not
+understand that there are restrictions even if the description of the
+algorithm does not say so.
+
    
+
    [Lillehammer: This is more general than for_each.  We don't want
+  the function object in transform invalidiating iterators
+  either. There should be a note somewhere in clause 17 (17, not 25)
+  saying that user code operating on a range may not invalidate
+  iterators unless otherwise specified.  Bill will provide wording.]
    
+
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+Moved to NAD.
+
    
+
    
+It was felt that the current description is adequate, and that there are
+limits to what the standard can reasonably say to prohibit perverse uses
+of the library.
+
    
+
    
+
+
+
+
    Proposed resolution:
    
+
+
+
+
+
+
+
    
+
    293. Order of execution in transform algorithm
    
+
    Section: 25.4.4 [alg.transform] Status: NAD
+ Submitter: Angelika Langer Opened: 2001-01-04  Last modified: 2007-01-15
    
+
    View all other issues in [alg.transform].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    This issue is related to issue 242.  In case that the resolution
@@ -3732,136 +4283,6 @@ specification of pair.
    
 
 
 
    
-
    299. Incorrect return types for iterator dereference
    
-
    Section: 24.2.5 [bidirectional.iterators], 24.2.6 [random.access.iterators] Status: NAD Editorial
- Submitter: John Potter Opened: 2001-01-22  Last modified: 2008-09-26
    
-
    View all other issues in [bidirectional.iterators].
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
-
    
-In section 24.2.5 [bidirectional.iterators],
-Table 75 gives the return type of *r-- as convertible to T.  This is
-not consistent with Table 74 which gives the return type of *r++ as
-T&.  *r++ = t is valid while *r-- = t is invalid.
-
    
-
-
    
-In section 24.2.6 [random.access.iterators],
-Table 76 gives the return type of a[n] as convertible to T.  This is
-not consistent with the semantics of *(a + n) which returns T& by
-Table 74.  *(a + n) = t is valid while a[n] = t is invalid.
-
    
-
-
    
-Discussion from the Copenhagen meeting: the first part is
-uncontroversial.  The second part, operator[] for Random Access
-Iterators, requires more thought.  There are reasonable arguments on
-both sides.  Return by value from operator[] enables some potentially
-useful iterators, e.g. a random access "iota iterator" (a.k.a
-"counting iterator" or "int iterator").  There isn't any obvious way
-to do this with return-by-reference, since the reference would be to a
-temporary.  On the other hand, reverse_iterator takes an
-arbitrary Random Access Iterator as template argument, and its
-operator[] returns by reference.  If we decided that the return type
-in Table 76 was correct, we would have to change
-reverse_iterator.  This change would probably affect user
-code.
-
    
-
-
    
-History: the contradiction between reverse_iterator and the
-Random Access Iterator requirements has been present from an early
-stage.  In both the STL proposal adopted by the committee
-(N0527==94-0140) and the STL technical report (HPL-95-11 (R.1), by
-Stepanov and Lee), the Random Access Iterator requirements say that
-operator[]'s return value is "convertible to T".  In N0527
-reverse_iterator's operator[] returns by value, but in HPL-95-11
-(R.1), and in the STL implementation that HP released to the public,
-reverse_iterator's operator[] returns by reference.  In 1995, the
-standard was amended to reflect the contents of HPL-95-11 (R.1).  The
-original intent for operator[] is unclear.
-
    
-
-
    
-In the long term it may be desirable to add more fine-grained 
-iterator requirements, so that access method and traversal strategy
-can be decoupled.  (See "Improved Iterator Categories and
-Requirements", N1297 = 01-0011, by Jeremy Siek.)  Any decisions
-about issue 299 should keep this possibility in mind.
-
    
-
-
    Further discussion: I propose a compromise between John Potter's
-resolution, which requires T& as the return type of
-a[n], and the current wording, which requires convertible to
-T. The compromise is to keep the convertible to T
-for the return type of the expression a[n], but to also add
-a[n] = t as a valid expression. This compromise "saves" the
-common case uses of random access iterators, while at the same time
-allowing iterators such as counting iterator and caching file
-iterators to remain random access iterators (iterators where the
-lifetime of the object returned by operator*() is tied to the
-lifetime of the iterator).
-
    
-
-
    
-Note that the compromise resolution necessitates a change to
-reverse_iterator. It would need to use a proxy to support
-a[n] = t.
-
    
-
-
    
-Note also there is one kind of mutable random access iterator that
-will no longer meet the new requirements. Currently, iterators that
-return an r-value from operator[] meet the requirements for a
-mutable random access iterartor, even though the expression a[n] =
-t will only modify a temporary that goes away. With this proposed
-resolution, a[n] = t will be required to have the same
-operational semantics as *(a + n) = t.
-
    
-
-
-
-
    Proposed resolution:
    
-
-
    
-In section 24.1.4 [lib.bidirectdional.iterators], change the return
-type in table 75 from "convertible to T" to
-T&.
-
    
-
-
    
-In section 24.1.5 [lib.random.access.iterators], change the
-operational semantics for a[n] to " the r-value of
-a[n] is equivalent to the r-value of *(a +
-n)". Add a new row in the table for the expression a[n] = t
-with a return type of convertible to T and operational semantics of
-*(a + n) = t.
-
    
-
-
    [Lillehammer: Real problem, but should be addressed as part of
-  iterator redesign]
    
-
-
-
-
-
    Rationale:
    
-
    [
-San Francisco:
-]
    
-
-
-
    
-Solved by
-N2758.
-
    
-
-
-
-
-
-
-
-
    
 
    302. Need error indication from codecvt<>::do_length
    
 
    Section: 22.4.1.5 [locale.codecvt.byname] Status: NAD
  Submitter: Gregory Bumgardner Opened: 2001-01-25  Last modified: 2006-12-27
    
@@ -3979,6 +4400,329 @@ buffered somewhere to make a legal input iterator.
 
 
 
    
+
    309. Does sentry catch exceptions?
    
+
    Section: 27.7 [iostream.format] Status: NAD
+ Submitter: Martin Sebor Opened: 2001-03-19  Last modified: 2009-07-14
    
+
    View all other issues in [iostream.format].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    
+The descriptions of the constructors of basic_istream<>::sentry
+(27.7.1.1.3 [istream::sentry]) and basic_ostream<>::sentry
+(27.7.2.4 [ostream::sentry]) do not explain what the functions do in
+case an exception is thrown while they execute. Some current
+implementations allow all exceptions to propagate, others catch them
+and set ios_base::badbit instead, still others catch some but let
+others propagate.
+
    
+
+
    
+The text also mentions that the functions may call setstate(failbit)
+(without actually saying on what object, but presumably the stream
+argument is meant).  That may have been fine for
+basic_istream<>::sentry prior to issue 195, since
+the function performs an input operation which may fail. However,
+issue 195 amends 27.7.1.1.3 [istream::sentry], p2 to
+clarify that the function should actually call setstate(failbit |
+eofbit), so the sentence in p3 is redundant or even somewhat
+contradictory.
+
    
+
+
    
+The same sentence that appears in 27.7.2.4 [ostream::sentry], p3
+doesn't seem to be very meaningful for basic_istream<>::sentry
+which performs no input. It is actually rather misleading since it
+would appear to guide library implementers to calling
+setstate(failbit) when os.tie()->flush(), the only called function,
+throws an exception (typically, it's badbit that's set in response to
+such an event).
+
    
+
+
    Additional comments from Martin, who isn't comfortable with the
+    current proposed resolution (see c++std-lib-11530)
    
+
+
    
+The istream::sentry ctor says nothing about how the function
+deals with exemptions (27.6.1.1.2, p1 says that the class is
+responsible for doing "exception safe"(*) prefix and suffix
+operations but it doesn't explain what level of exception
+safety the class promises to provide). The mockup example
+of a "typical implementation of the sentry ctor" given in
+27.6.1.1.2, p6, removed in ISO/IEC 14882:2003, doesn't show
+exception handling, either. Since the ctor is not classified
+as a formatted or unformatted input function, the text in
+27.6.1.1, p1 through p4 does not apply. All this would seem
+to suggest that the sentry ctor should not catch or in any
+way handle exceptions thrown from any functions it may call.
+Thus, the typical implementation of an istream extractor may
+look something like [1].
+
    
+
+
    
+The problem with [1] is that while it correctly sets ios::badbit
+if an exception is thrown from one of the functions called from
+the sentry ctor, if the sentry ctor reaches EOF while extracting
+whitespace from a stream that has eofbit or failbit set in
+exceptions(), it will cause an ios::failure to be thrown, which
+will in turn cause the extractor to set ios::badbit.
+
    
+
+
    
+The only straightforward way to prevent this behavior is to
+move the definition of the sentry object in the extractor
+above the try block (as suggested by the example in 22.2.8,
+p9 and also indirectly supported by 27.6.1.3, p1). See [2].
+But such an implementation will allow exceptions thrown from
+functions called from the ctor to freely propagate to the
+caller regardless of the setting of ios::badbit in the stream
+object's exceptions().
+
    
+
+
    
+So since neither [1] nor [2] behaves as expected, the only
+possible solution is to have the sentry ctor catch exceptions
+thrown from called functions, set badbit, and propagate those
+exceptions if badbit is also set in exceptions(). (Another
+solution exists that deals with both kinds of sentries, but
+the code is non-obvious and cumbersome -- see [3].)
+
    
+
+
    
+Please note that, as the issue points out, current libraries
+do not behave consistently, suggesting  that implementors are
+not quite clear on the exception handling in istream::sentry,
+despite the fact that some LWG members might feel otherwise.
+(As documented by the parenthetical comment here:
+http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/2003/n1480.html#309)
+
    
+
+
    
+Also please note that those LWG members who in Copenhagen
+felt that "a sentry's constructor should not catch exceptions,
+because sentries should only be used within (un)formatted input
+functions and that exception handling is the responsibility of
+those functions, not of the sentries," as noted here
+http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/papers/2001/n1310.html#309
+would in effect be either arguing for the behavior described
+in [1] or for extractors implemented along the lines of [3].
+
    
+
+
    
+The original proposed resolution (Revision 25 of the issues
+list) clarifies the role of the sentry ctor WRT exception
+handling by making it clear that extractors (both library
+or user-defined) should be implemented along the lines of
+[2] (as opposed to [1]) and that no exception thrown from
+the callees should propagate out of either function unless
+badbit is also set in exceptions().
+
    
+
+
+
    [1] Extractor that catches exceptions thrown from sentry:
    
+
+
    
+
    struct S { long i; };
+
+istream& operator>> (istream &strm, S &s)
+{
+    ios::iostate err = ios::goodbit;
+    try {
+        const istream::sentry guard (strm, false);
+        if (guard) {
+            use_facet<num_get<char> >(strm.getloc ())
+                .get (istreambuf_iterator<char>(strm),
+                      istreambuf_iterator<char>(),
+                      strm, err, s.i);
+        }
+    }
+    catch (...) {
+        bool rethrow;
+        try {
+            strm.setstate (ios::badbit);
+            rethrow = false;
+        }
+        catch (...) {
+            rethrow = true;
+        }
+        if (rethrow)
+            throw;
+    }
+    if (err)
+        strm.setstate (err);
+    return strm;
+}
+
    
+
    
+
+
    [2] Extractor that propagates exceptions thrown from sentry:
    
+
+
    
+
    istream& operator>> (istream &strm, S &s)
+{
+    istream::sentry guard (strm, false);
+    if (guard) {
+        ios::iostate err = ios::goodbit;
+        try {
+            use_facet<num_get<char> >(strm.getloc ())
+                .get (istreambuf_iterator<char>(strm),
+                      istreambuf_iterator<char>(),
+                      strm, err, s.i);
+        }
+        catch (...) {
+            bool rethrow;
+            try {
+                strm.setstate (ios::badbit);
+                rethrow = false;
+            }
+            catch (...) {
+                rethrow = true;
+            }
+            if (rethrow)
+                throw;
+        }
+        if (err)
+            strm.setstate (err);
+    }
+    return strm;
+}
+
    
+
    
+
+
    
+[3] Extractor that catches exceptions thrown from sentry
+but doesn't set badbit if the exception was thrown as a
+result of a call to strm.clear().
+
    
+
+
    
+
    istream& operator>> (istream &strm, S &s)
+{
+    const ios::iostate state = strm.rdstate ();
+    const ios::iostate except = strm.exceptions ();
+    ios::iostate err = std::ios::goodbit;
+    bool thrown = true;
+    try {
+        const istream::sentry guard (strm, false);
+        thrown = false;
+        if (guard) {
+            use_facet<num_get<char> >(strm.getloc ())
+                .get (istreambuf_iterator<char>(strm),
+                      istreambuf_iterator<char>(),
+                      strm, err, s.i);
+        }
+    }
+    catch (...) {
+        if (thrown && state & except)
+            throw;
+        try {
+            strm.setstate (ios::badbit);
+            thrown = false;
+        }
+        catch (...) {
+            thrown = true;
+        }
+        if (thrown)
+            throw;
+    }
+    if (err)
+        strm.setstate (err);
+
+    return strm;
+}
+
    
+
    
+
+
    
+[Pre-Berlin] Reopened at the request of Paolo Carlini and Steve Clamage.
+
    
+
+
    
+[Pre-Portland] A relevant newsgroup post:
+
    
+
+
    
+The current proposed resolution of issue #309
+(http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#309)  is
+unacceptable.   I write commerical software and coding around this
+makes my code ugly, non-intuitive, and requires comments referring
+people to this very issue.   Following is the full explanation of my
+experience.
+
    
+
    
+In the course of writing software for commercial use, I constructed
+std::ifstream's based on user-supplied pathnames on typical POSIX
+systems.
+
    
+
    
+It was expected that some files that opened successfully might not read
+successfully -- such as a pathname which actually refered to a
+directory.   Intuitively, I expected the streambuffer underflow() code
+to throw an exception in this situation, and recent implementations of
+libstdc++'s basic_filebuf do just that (as well as many of my own
+custom streambufs).
+
    
+
    
+I also intuitively expected that the istream code would convert these
+exceptions to the "badbit' set on the stream object, because I had not
+requested exceptions.    I refer to 27.6.1.1. P4.
+
    
+
    
+However, this was not the case on at least two implementations -- if
+the first thing I did with an istream was call operator>>( T& ) for T
+among the basic arithmetic types and std::string.   Looking further I
+found that the sentry's constructor was invoking the exception when it
+pre-scanned for whitespace, and the extractor function (operator>>())
+was not catching exceptions in this situation.
+
    
+
    
+So, I was in a situation where setting 'noskipws' would change the
+istream's behavior even though no characters (whitespace or not) could
+ever be successfully read.
+
    
+
    
+Also, calling .peek() on the istream before calling the extractor()
+changed the behavior (.peek() had the effect of setting the badbit
+ahead of time).
+
    
+
    
+I found this all to be so inconsistent and inconvenient for me and my
+code design, that I filed a bugzilla entry for libstdc++.   I was then
+told that the bug cannot be fixed until issue #309 is resolved by the
+committee.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+Moved to NAD.
+
    
+
    
+See the rationale in the issue. Paolo, who requested that the issue be
+reopened, agreed with the rationale.
+
    
+
    
+
+
+
+
    Proposed resolution:
    
+
+
+
    Rationale:
    
+
    The LWG agrees there is minor variation between implementations,
+  but believes that it doesn't matter. This is a rarely used corner
+  case. There is no evidence that this has any commercial importance
+  or that it causes actual portability problems for customers trying
+  to write code that runs on multiple implementations.
    
+
+
+
+
+
+
    
 
    313. set_terminate and set_unexpected question
    
 
    Section: 18.8.3.3 [terminate] Status: NAD
  Submitter: Judy Ward Opened: 2001-04-03  Last modified: 2006-12-27
    
@@ -4116,7 +4860,7 @@ the correct headers are #included.
 
    Redmond: PJP reports that C99 adds two new kinds of abs: complex,
 and int_max_abs.
    
 
-
    Related issue: 343.
    
+
    Related issue: 343.
    
 
 
    [
 Bellevue:
@@ -4272,57 +5016,434 @@ report.  Additionally, nobody saw a clear need for this extension;
 
 
 
    
-
    344. grouping + showbase
    
-
    Section: 22.4.2 [category.numeric] Status: NAD
- Submitter: Howard Hinnant Opened: 2001-10-13  Last modified: 2007-01-15
    
+
    342. seek and eofbit
    
+
    Section: 27.7.1.3 [istream.unformatted] Status: NAD
+ Submitter: Howard Hinnant Opened: 2001-10-09  Last modified: 2009-07-14
    
+
    View all other issues in [istream.unformatted].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
-
    
-When both grouping and showbase are active and the basefield is octal, 
-does the leading 0 participate in the grouping or not?  For example, 
-should one format as: 0,123,456 or 0123,456?
-
    
-
    
-An analogy can be drawn with hexadecimal.  It appears that 0x123,456 is 
-preferred over 0x,123,456.  However, this analogy is not universally 
-accepted to apply to the octal base.  The standard is not clear on how 
-to format (or parse) in this manner.
-
    
+
    I think we have a defect.
    
+
+
    According to lwg issue 60 which is now a dr, the
+description of seekg in 27.7.1.3 [istream.unformatted] paragraph 38 now looks
+like:
    
 
-
    Proposed resolution:
    
-
    
-Insert into 22.4.3.1.2 [facet.numpunct.virtuals] paragraph 3, just before the last
-sentence:
-
    
 
    
-The leading hexadecimal base specifier "0x" does not participate in 
-grouping.  The leading '0' octal base specifier may participate in 
-grouping.  It is unspecified if the leading '0' participates in 
-formatting octal numbers.  In parsing octal numbers, the implementation 
-is encouraged to accept both the leading '0' participating in the 
-grouping, and not participating (e.g. 0123,456 or 0,123,456).
+Behaves as an unformatted input function (as described in 27.6.1.3, 
+paragraph 1), except that it does not count the number of characters 
+extracted and does not affect the value returned by subsequent calls to 
+gcount(). After constructing a sentry object, if fail() != true, 
+executes rdbuf()->pubseekpos( pos).
+
    
+
+
    And according to lwg issue 243 which is also now a dr,
+27.6.1.3, paragraph 1 looks like:
    
+
+
    
+Each unformatted input function begins execution by constructing an 
+object of class sentry with the default argument noskipws (second) 
+argument true. If the sentry object returns true, when converted to a 
+value of type bool, the function endeavors to obtain the requested 
+input.  Otherwise, if the sentry constructor exits by throwing an 
+exception or if the sentry object returns false, when converted to a 
+value of type bool, the function returns without attempting to obtain 
+any input. In either case the number of extracted characters is set to 
+0; unformatted input functions taking a character array of non-zero 
+size as an argument shall also store a null character (using charT()) 
+in the first location of the array. If an exception is thrown during 
+input then ios::badbit is turned on in *this'ss error state. If 
+(exception()&badbit)!= 0 then the exception is rethrown. It also counts 
+the number of characters extracted. If no exception has been thrown it 
+ends by storing the count in a member object and returning the value 
+specified. In any event the sentry object is destroyed before leaving 
+the unformatted input function.
+
    
+
+
    And finally 27.6.1.1.2/5 says this about sentry:
    
+
+
    
+If, after any preparation is completed, is.good() is true, ok_ != false 
+otherwise, ok_ == false.
 
    
 
-
    Rationale:
    
 
    
-The current behavior may be unspecified, but it's not clear that it
-matters.  This is an obscure corner case, since grouping is usually
-intended for the benefit of humans and oct/hex prefixes are usually
-intended for the benefit of machines.  There is not a strong enough
-consensus in the LWG for action.
+So although the seekg paragraph says that the operation proceeds if 
+!fail(), the behavior of unformatted functions says the operation 
+proceeds only if good().  The two statements are contradictory when only 
+eofbit is set.  I don't think the current text is clear which condition 
+should be respected.
 
    
 
+
    Further discussion from Redmond:
    
 
+
    PJP: It doesn't seem quite right to say that seekg is
+"unformatted". That makes specific claims about sentry that
+aren't quite appropriate for seeking, which has less fragile failure
+modes than actual input.  If we do really mean that it's unformatted
+input, it should behave the same way as other unformatted input.  On
+the other hand, "principle of least surprise" is that seeking from EOF
+ought to be OK.
    
 
+
    
+Pre-Berlin:  Paolo points out several problems with the proposed resolution in
+Ready state:
+
    
 
-
    
+
      
+
    • It should apply to both overloads of seekg.
      • 
+
    • tellg has similar issues, except that it should not call clear().
      • 
+
    • The point about clear() seems to apply to seekp().
      • 
+
    • Depending on the outcome of 419
+if the sentry
+sets failbit when it finds eofbit already set, then
+you can never seek away from the end of stream.
      • 
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+Moved to NAD. Will reopen if proposed resolution is supplied.
+
    
+
    
+
+
+
+
    Proposed resolution:
    
+
+
    Change 27.7.1.3 [istream.unformatted] to:
    
+
    
+Behaves as an unformatted input function (as described in 27.6.1.3,
+paragraph 1), except that it does not count the number of characters
+extracted, does not affect the value returned by subsequent calls to
+gcount(), and does not examine the value returned by the sentry
+object. After constructing a sentry object, if fail() !=
+true, executes rdbuf()->pubseekpos(pos).  In
+case of success, the function calls clear().
+In case of failure, the function calls setstate(failbit)
+(which may throw ios_base::failure).
+
    
+
+
    [Lillehammer: Matt provided wording.]
    
+
+
+
+
+
    Rationale:
    
+
    In C, fseek does clear EOF.  This is probably what most users would
+  expect.  We agree that having eofbit set should not deter a seek,
+  and that a successful seek should clear eofbit. Note
+  that fail() is true only if failbit
+  or badbit is set, so using !fail(), rather
+  than good(), satisfies this goal.
    
+
+
+
+
+
+
    
+
    343. Unspecified library header dependencies
    
+
    Section: 17 [library] Status: NAD
+ Submitter: Martin Sebor Opened: 2001-10-09  Last modified: 2009-07-28
    
+
    View other active issues in [library].
    
+
    View all other issues in [library].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    
+The synopses of the C++ library headers clearly show which names are
+required to be defined in each header. Since in order to implement the
+classes and templates defined in these headers declarations of other
+templates (but not necessarily their definitions) are typically
+necessary the standard in 17.4.4, p1 permits library implementers to
+include any headers needed to implement the definitions in each header.
+
    
+
+
    
+For instance, although it is not explicitly specified in the synopsis of
+<string>, at the point of definition of the std::basic_string template
+the declaration of the std::allocator template must be in scope. All
+current implementations simply include <memory> from within <string>,
+either directly or indirectly, to bring the declaration of
+std::allocator into scope.
+
    
+
+
    
+Additionally, however, some implementation also include <istream> and
+<ostream> at the top of <string> to bring the declarations of
+std::basic_istream and std::basic_ostream into scope (which are needed
+in order to implement the string inserter and extractor operators
+(21.3.7.9 [lib.string.io])). Other implementations only include
+<iosfwd>, since strictly speaking, only the declarations and not the
+full definitions are necessary.
+
    
+
+
    
+Obviously, it is possible to implement <string> without actually
+providing the full definitions of all the templates std::basic_string
+uses (std::allocator, std::basic_istream, and std::basic_ostream).
+Furthermore, not only is it possible, doing so is likely to have a
+positive effect on compile-time efficiency.
+
    
+
+
    
+But while it may seem perfectly reasonable to expect a program that uses
+the std::basic_string insertion and extraction operators to also
+explicitly include <istream> or <ostream>, respectively, it doesn't seem
+reasonable to also expect it to explicitly include <memory>. Since
+what's reasonable and what isn't is highly subjective one would expect
+the standard to specify what can and what cannot be assumed.
+Unfortunately, that isn't the case.
+
    
+
+
    The examples below demonstrate the issue.
    
+
+
    Example 1:
    
+
+
    It is not clear whether the following program is complete:
    
+
+
    #include <string>
+
+extern std::basic_ostream<char> &strm;
+
+int main () {
+    strm << std::string ("Hello, World!\n");
+}
+
        
+
+
    or whether one must explicitly include <memory> or
+<ostream> (or both) in addition to <string> in order for
+the program to compile.
    
+
+
+
    Example 2:
    
+
+
    Similarly, it is unclear whether the following program is complete:
    
+
+
    #include <istream>
+
+extern std::basic_iostream<char> &strm;
+
+int main () {
+    strm << "Hello, World!\n";
+}
+
    
+
+
    
+or whether one needs to explicitly include <ostream>, and
+perhaps even other headers containing the definitions of other
+required templates:
    
+
+
    #include <ios>
+#include <istream>
+#include <ostream>
+#include <streambuf>
+
+extern std::basic_iostream<char> &strm;
+
+int main () {
+    strm << "Hello, World!\n";
+}
+
    
+
+
    Example 3:
    
+
+
    Likewise, it seems unclear whether the program below is complete:
    
+
    #include <iterator>
+
+bool foo (std::istream_iterator<int> a, std::istream_iterator<int> b)
+{
+    return a == b;
+}
+
+int main () { }
+
    
+
+
    or whether one should be required to include <istream>.
    
+
+
    There are many more examples that demonstrate this lack of a
+requirement.  I believe that in a good number of cases it would be
+unreasonable to require that a program explicitly include all the
+headers necessary for a particular template to be specialized, but I
+think that there are cases such as some of those above where it would
+be desirable to allow implementations to include only as much as
+necessary and not more.
    
+
+
    [
+post Bellevue:
+]
    
+
+
+
    
+Position taken in prior reviews is that the idea of a table of header
+dependencies is a good one. Our view is that a full paper is needed to
+do justice to this, and we've made that recommendation to the issue
+author.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+NAD. Handled by LWG 1178.
+
    
+
+
+
+
    Proposed resolution:
    
+
    
+For every C++ library header, supply a minimum set of other C++ library
+headers that are required to be included by that header. The proposed
+list is below (C++ headers for C Library Facilities, table 12 in
+17.4.1.2, p3, are omitted):
+
    
+
+
    +------------+--------------------+
+| C++ header |required to include |
++============+====================+
+|<algorithm> |                    |
++------------+--------------------+
+|<bitset>    |                    |
++------------+--------------------+
+|<complex>   |                    |
++------------+--------------------+
+|<deque>     |<memory>            |
++------------+--------------------+
+|<exception> |                    |
++------------+--------------------+
+|<fstream>   |<ios>               |
++------------+--------------------+
+|<functional>|                    |
++------------+--------------------+
+|<iomanip>   |<ios>               |
++------------+--------------------+
+|<ios>       |<streambuf>         |
++------------+--------------------+
+|<iosfwd>    |                    |
++------------+--------------------+
+|<iostream>  |<istream>, <ostream>|
++------------+--------------------+
+|<istream>   |<ios>               |
++------------+--------------------+
+|<iterator>  |                    |
++------------+--------------------+
+|<limits>    |                    |
++------------+--------------------+
+|<list>      |<memory>            |
++------------+--------------------+
+|<locale>    |                    |
++------------+--------------------+
+|<map>       |<memory>            |
++------------+--------------------+
+|<memory>    |                    |
++------------+--------------------+
+|<new>       |<exception>         |
++------------+--------------------+
+|<numeric>   |                    |
++------------+--------------------+
+|<ostream>   |<ios>               |
++------------+--------------------+
+|<queue>     |<deque>             |
++------------+--------------------+
+|<set>       |<memory>            |
++------------+--------------------+
+|<sstream>   |<ios>, <string>     |
++------------+--------------------+
+|<stack>     |<deque>             |
++------------+--------------------+
+|<stdexcept> |                    |
++------------+--------------------+
+|<streambuf> |<ios>               |
++------------+--------------------+
+|<string>    |<memory>            |
++------------+--------------------+
+|<strstream> |                    |
++------------+--------------------+
+|<typeinfo>  |<exception>         |
++------------+--------------------+
+|<utility>   |                    |
++------------+--------------------+
+|<valarray>  |                    |
++------------+--------------------+
+|<vector>    |<memory>            |
++------------+--------------------+
+
    
+
+
+
    Rationale:
    
+
    The portability problem is real.  A program that works correctly on
+one implementation might fail on another, because of different header
+dependencies.  This problem was understood before the standard was
+completed, and it was a conscious design choice.
    
+
    One possible way to deal with this, as a library extension, would
+be an <all> header.
    
+
+
    
+Hinnant:  It's time we dealt with this issue for C++0X.  Reopened.
+
    
+
+
+
+
+
+
+
+
    
+
    344. grouping + showbase
    
+
    Section: 22.4.2 [category.numeric] Status: NAD
+ Submitter: Howard Hinnant Opened: 2001-10-13  Last modified: 2007-01-15
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    
+When both grouping and showbase are active and the basefield is octal, 
+does the leading 0 participate in the grouping or not?  For example, 
+should one format as: 0,123,456 or 0123,456?
+
    
+
    
+An analogy can be drawn with hexadecimal.  It appears that 0x123,456 is 
+preferred over 0x,123,456.  However, this analogy is not universally 
+accepted to apply to the octal base.  The standard is not clear on how 
+to format (or parse) in this manner.
+
    
+
+
    Proposed resolution:
    
+
    
+Insert into 22.4.3.1.2 [facet.numpunct.virtuals] paragraph 3, just before the last
+sentence:
+
    
+
    
+The leading hexadecimal base specifier "0x" does not participate in 
+grouping.  The leading '0' octal base specifier may participate in 
+grouping.  It is unspecified if the leading '0' participates in 
+formatting octal numbers.  In parsing octal numbers, the implementation 
+is encouraged to accept both the leading '0' participating in the 
+grouping, and not participating (e.g. 0123,456 or 0,123,456).
+
    
+
+
    Rationale:
    
+
    
+The current behavior may be unspecified, but it's not clear that it
+matters.  This is an obscure corner case, since grouping is usually
+intended for the benefit of humans and oct/hex prefixes are usually
+intended for the benefit of machines.  There is not a strong enough
+consensus in the LWG for action.
+
    
+
+
+
+
+
    
 
    348. Minor issue with std::pair operator<
    
 
    Section: 20.3.3 [pairs] Status: Dup
  Submitter: Andy Sawyer Opened: 2001-10-23  Last modified: 2008-01-05
    
 
    View other active issues in [pairs].
    
 
    View all other issues in [pairs].
    
 
    View all issues with Dup status.
    
-
    Duplicate of: 532
    
+
    Duplicate of: 532
    
 
    Discussion:
    
 
 
@@ -4366,7 +5487,7 @@ operator< on any pair type which contains a pointer.
 
 
    
 
    350. allocator<>::address
    
-
    Section: 20.8.6.1 [allocator.members], X [allocator.requirements], 17.6.1.1 [contents] Status: Dup
+
    Section: 20.8.4.1 [allocator.members], X [allocator.requirements], 17.6.1.1 [contents] Status: Dup
  Submitter: Nathan Myers Opened: 2001-10-25  Last modified: 2007-10-11
    
 
    View all other issues in [allocator.members].
    
 
    View all issues with Dup status.
    
@@ -4758,6 +5879,7 @@ discussion concur.
    
 
    361. num_get<>::do_get (..., void*&) checks grouping
    
 
    Section: 22.4.2.2.2 [facet.num.put.virtuals] Status: NAD
  Submitter: Martin Sebor Opened: 2002-03-12  Last modified: 2007-01-15
    
+
    View other active issues in [facet.num.put.virtuals].
    
 
    View all other issues in [facet.num.put.virtuals].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -4812,7 +5934,6 @@ Change the first sentence of 22.2.2.2.2, p12 from
 
    366. Excessive const-qualification
    
 
    Section: 27 [input.output] Status: NAD
  Submitter: Walter Brown, Marc Paterno Opened: 2002-05-10  Last modified: 2006-12-27
    
-
    View other active issues in [input.output].
    
 
    View all other issues in [input.output].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
@@ -5151,6 +6272,146 @@ out of scope?
 
 
 
    
+
    382. codecvt do_in/out result
    
+
    Section: 22.4.1.4 [locale.codecvt] Status: NAD
+ Submitter: Martin Sebor Opened: 2002-08-30  Last modified: 2009-07-14
    
+
    View all other issues in [locale.codecvt].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    
+It seems that the descriptions of codecvt do_in() and do_out() leave
+sufficient room for interpretation so that two implementations of
+codecvt may not work correctly with the same filebuf. Specifically,
+the following seems less than adequately specified:
+
    
+
+
      
+
    1. 
+  the conditions under which the functions terminate
+
      2. 
+
    2. 
+  precisely when the functions return ok
+
      3. 
+
    3. 
+  precisely when the functions return partial
+
      4. 
+
    4. 
+  the full set of conditions when the functions return error
+
      5. 
+
    
+
+
      
+
    1. 
+   22.4.1.4.2 [locale.codecvt.virtuals], p2 says this about the effects of the
+   function: ...Stops if it encounters a character it cannot
+   convert...  This assumes that there *is* a character to
+   convert. What happens when there is a sequence that doesn't form a
+   valid source character, such as an unassigned or invalid UNICODE
+   character, or a sequence that cannot possibly form a character
+   (e.g., the sequence "\xc0\xff" in UTF-8)?
+
      2. 
+
    2. 
+   Table 53 says that the function returns codecvt_base::ok
+   to indicate that the function(s) "completed the conversion."
+   Suppose that the source sequence is "\xc0\x80" in UTF-8,
+   with from pointing to '\xc0' and (from_end==from + 1).
+   It is not clear whether the return value should be ok
+   or partial (see below).
+
      3. 
+
    3. 
+   Table 53 says that the function returns codecvt_base::partial
+   if "not all source characters converted." With the from pointers
+   set up the same way as above, it is not clear whether the return
+   value should be partial or ok (see above).
+
      4. 
+
    4. 
+   Table 53, in the row describing the meaning of error mistakenly
+   refers to a "from_type" character, without the symbol from_type
+   having been defined. Most likely, the word "source" character
+   is intended, although that is not sufficient. The functions
+   may also fail when they encounter an invalid source sequence
+   that cannot possibly form a valid source character (e.g., as
+   explained in bullet 1 above).
+
      5. 
+
    
+
    
+Finally, the conditions described at the end of 22.4.1.4.2 [locale.codecvt.virtuals], p4 don't seem to be possible:
+
    
+
    
+    "A return value of partial, if (from_next == from_end),
+    indicates that either the destination sequence has not
+    absorbed all the available destination elements, or that
+    additional source elements are needed before another
+    destination element can be produced."
+
    
+
    
+If the value is partial, it's not clear to me that (from_next
+==from_end) could ever hold if there isn't enough room
+in the destination buffer. In order for (from_next==from_end) to
+hold, all characters in that range must have been successfully
+converted (according to 22.4.1.4.2 [locale.codecvt.virtuals], p2) and since there are no
+further source characters to convert, no more room in the
+destination buffer can be needed.
+
    
+
    
+It's also not clear to me that (from_next==from_end) could ever
+hold if additional source elements are needed to produce another
+destination character (not element as incorrectly stated in the
+text). partial is returned if "not all source characters have
+been converted" according to Table 53, which also implies that
+(from_next==from) does NOT hold.
+
    
+
    
+Could it be that the intended qualifying condition was actually
+(from_next != from_end), i.e., that the sentence was supposed
+to read
+
    
+
    
+    "A return value of partial, if (from_next != from_end),..."
+
    
+
    
+which would make perfect sense, since, as far as I understand it,
+partial can only occur if (from_next != from_end)?
+
    
+
    [Lillehammer: Defer for the moment, but this really needs to be
+  fixed. Right now, the description of codecvt is too vague for it to
+  be a useful contract between providers and clients of codecvt
+  facets.  (Note that both vendors and users can be both providers and
+  clients of codecvt facets.) The major philosophical issue is whether
+  the standard should only describe mappings that take a single wide
+  character to multiple narrow characters (and vice versa), or whether
+  it should describe fully general N-to-M conversions. When the
+  original standard was written only the former was contemplated, but
+  today, in light of the popularity of utf8 and utf16, that doesn't
+  seem sufficient for C++0x. Bill supports general N-to-M conversions;
+  we need to make sure Martin and Howard agree.]
    
+
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+
    
+codecvt is meant to be a 1-to-N to N-to-1 conversion. It does not work
+well for N-to-M conversions. wbuffer_convert now exists, and handles
+N-to-M cases. Also, there is a new specialization of codecvt that
+permits UTF-16 <-> UTF-8 conversions.
+
    
+
    
+NAD without prejudice. Will reopen if proposed resolution is supplied.
+
    
+
    
+
+
+
+
    Proposed resolution:
    
+
+
+
+
+
    
 
    385. Does call by value imply the CopyConstructible requirement?
    
 
    Section: 17 [library] Status: NAD
  Submitter: Matt Austern Opened: 2002-10-23  Last modified: 2007-04-18
    
@@ -5305,6 +6566,7 @@ provide their own comparison function object.
    
 
    390. CopyConstructible requirements too strict
    
 
    Section: X [utility.arg.requirements] Status: NAD Editorial
  Submitter: Doug Gregor Opened: 2002-10-24  Last modified: 2008-03-14
    
+
    View other active issues in [utility.arg.requirements].
    
 
    View all other issues in [utility.arg.requirements].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
@@ -5496,374 +6758,580 @@ correct. Proposed Disposition: NAD, Editorial
 
 
 
    
-
    399. volations of unformatted input function requirements
    
-
    Section: 27.7.1.3 [istream.unformatted] Status: NAD
- Submitter: Martin Sebor Opened: 2003-01-05  Last modified: 2006-12-27
    
-
    View all other issues in [istream.unformatted].
    
+
    394. behavior of formatted output on failure
    
+
    Section: 27.7.2.6.1 [ostream.formatted.reqmts] Status: NAD
+ Submitter: Martin Sebor Opened: 2002-12-27  Last modified: 2009-07-14
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
-    
    
-The Effects clauses for the two functions below violate the
-general requirements on unformatted input functions outlined
-in 27.6.1.3: they do not begin by constructing a sentry object.
-Instead, they begin by calling widen ('\n'), which may throw
-an exception. The exception is then allowed to propagate from
-the unformatted input function irrespective of the setting of
-exceptions().
-    
    
-    
    
-Note that in light of 27.6.1.1, p3 and p4, the fact that the
-functions allow exceptions thrown from widen() to propagate
-may not strictly speaking be a defect (but the fact that the
-functions do not start by constructing a sentry object still
-is). However, since an exception thrown from ctype<charT>
-::widen() during any other input operation (say, from within
-a call to num_get<charT>::get()) will be caught and cause
-badbit to be set, these two functions should not be treated
-differently for the sake of consistency.
-    
    
-  
-
-
    Proposed resolution:
    
-
-
-
    Rationale:
    
 
    
-Not a defect.  The standard is consistent, and the behavior required
-by the standard is unambiguous.  Yes, it's theoretically possible for
-widen to throw.  (Not that this will happen for the default ctype
-facet or for most real-world replacement ctype facets.)  Users who
-define ctype facets that can throw, and who care about this behavior,
-can use alternative signatures that don't call widen.
+There is a contradiction in Formatted output about what bit is
+supposed to be set if the formatting fails. On sentence says it's
+badbit and another that it's failbit.
+
    
+
    
+27.6.2.5.1, p1 says in the Common Requirements on Formatted output
+functions:
+
    
+
         ... If the generation fails, then the formatted output function
+     does setstate(ios::failbit), which might throw an exception.
+
    
+
    
+27.6.2.5.2, p1 goes on to say this about Arithmetic Inserters:
+
    
+
    
+     ... The formatting conversion occurs as if it performed the
+     following code fragment:
 
    
+
         bool failed =
+         use_facet<num_put<charT,ostreambuf_iterator<charT,traits>
+         > >
+         (getloc()).put(*this, *this, fill(), val). failed();
 
+     ... If failed is true then does setstate(badbit) ...
+
    
+
    
+The original intent of the text, according to Jerry Schwarz (see
+c++std-lib-10500), is captured in the following paragraph:
+
    
+
    
+In general "badbit" should mean that the stream is unusable because
+of some underlying failure, such as disk full or socket closure;
+"failbit" should mean that the requested formatting wasn't possible
+because of some inconsistency such as negative widths.  So typically
+if you clear badbit and try to output something else you'll fail
+again, but if you clear failbit and try to output something else
+you'll succeed.
+
    
+
    
+In the case of the arithmetic inserters, since num_put cannot
+report failure by any means other than exceptions (in response
+to which the stream must set badbit, which prevents the kind of
+recoverable error reporting mentioned above), the only other
+detectable failure is if the iterator returned from num_put
+returns true from failed().
+
    
+
    
+Since that can only happen (at least with the required iostream
+specializations) under such conditions as the underlying failure
+referred to above (e.g., disk full), setting badbit would seem
+to be the appropriate response (indeed, it is required in
+27.6.2.5.2, p1). It follows that failbit can never be directly
+set by the arithmetic (it can only be set by the sentry object
+under some unspecified conditions).
+
    
+
    
+The situation is different for other formatted output functions
+which can fail as a result of the streambuf functions failing
+(they may do so by means other than exceptions), and which are
+then required to set failbit.
+
    
+
    
+The contradiction, then, is that ostream::operator<<(int) will
+set badbit if the disk is full, while operator<<(ostream&,
+char) will set failbit under the same conditions. To make the behavior
+consistent, the Common requirements sections for the Formatted output
+functions should be changed as proposed below.
+
    
+
    [Kona: There's agreement that this is a real issue.  What we
+  decided at Kona: 1. An error from the buffer (which can be detected
+  either directly from streambuf's member functions or by examining a
+  streambuf_iterator) should always result in badbit getting set.
+  2. There should never be a circumstance where failbit gets set.
+  That represents a formatting error, and there are no circumstances
+  under which the output facets are specified as signaling a
+  formatting error. (Even more so for string output that for numeric
+  because there's nothing to format.)  If we ever decide to make it
+  possible for formatting errors to exist then the facets can signal
+  the error directly, and that should go in clause 22, not clause 27.
+  3. The phrase "if generation fails" is unclear and should be
+  eliminated.  It's not clear whether it's intended to mean a buffer
+  error (e.g. a full disk), a formatting error, or something else.
+  Most people thought it was supposed to refer to buffer errors; if
+  so, we should say so.  Martin will provide wording.]
    
 
 
+
    [
+2009-07 Frankfurt
+]
    
 
 
+
    
+NAD. This issue is already fixed.
+
    
 
-
    
-
    429. typo in basic_ios::clear(iostate)
    
-
    Section: 27.5.4.3 [iostate.flags] Status: Dup
- Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2006-12-30
    
-
    View all other issues in [iostate.flags].
    
-
    View all issues with Dup status.
    
-
    Duplicate of: 412
    
-
    Discussion:
    
-        
    
 
-The Effects clause in 27.4.4.3, p5 describing the effects of a call to
-the ios_base member function clear(iostate state) says that the function
-only throws if the respective bits are already set prior to the function
-call. That's obviously not the intent. If it was, a call to clear(badbit)
-on an object for which (rdstate() == goodbit && exceptions() == badbit)
-holds would not result in an exception being thrown.
 
-        
    
-    
-    
    Proposed resolution:
    
-        
    
+
    Proposed resolution:
    
 
-The text ought to be changed from
-
    
 
-"If (rdstate() & exceptions()) == 0, returns. ..."
-
    
+
    Rationale:
    
 
-to
-
    
 
-"If (state & exceptions()) == 0, returns. ..."
-        
    
 
 
-
    Rationale:
    
 
 
+
    
+
    398. effects of end-of-file on unformatted input functions
    
+
    Section: 27.7.2.4 [ostream::sentry] Status: NAD
+ Submitter: Martin Sebor Opened: 2003-01-05  Last modified: 2009-07-14
    
+
    View all other issues in [ostream::sentry].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+    
    
+While reviewing unformatted input member functions of istream
+for their behavior when they encounter end-of-file during input
+I found that the requirements vary, sometimes unexpectedly, and
+in more than one case even contradict established practice (GNU
+libstdc++ 3.2, IBM VAC++ 6.0, STLPort 4.5, SunPro 5.3, HP aCC
+5.38, Rogue Wave libstd 3.1, and Classic Iostreams).
+    
    
+    
    
+The following unformatted input member functions set eofbit if they
+encounter an end-of-file (this is the expected behavior, and also
+the behavior of all major implementations):
+    
    
+    
        basic_istream<charT, traits>&
+    get (char_type*, streamsize, char_type);
+    
    
+    
    
+    Also sets failbit if it fails to extract any characters.
+    
    
+    
        basic_istream<charT, traits>&
+    get (char_type*, streamsize);
+    
    
+    
    
+    Also sets failbit if it fails to extract any characters.
+    
    
+    
        basic_istream<charT, traits>&
+    getline (char_type*, streamsize, char_type);
+    
    
+    
    
+    Also sets failbit if it fails to extract any characters.
+    
    
+    
        basic_istream<charT, traits>&
+    getline (char_type*, streamsize);
+    
    
+    
    
+    Also sets failbit if it fails to extract any characters.
+    
    
+    
        basic_istream<charT, traits>&
+    ignore (int, int_type);
+    
    
+    
        basic_istream<charT, traits>&
+    read (char_type*, streamsize);
+    
    
+    
    
+    Also sets failbit if it encounters end-of-file.
+    
    
+    
        streamsize readsome (char_type*, streamsize);
+    
    
+
+    
    
+The following unformated input member functions set failbit but
+not eofbit if they encounter an end-of-file (I find this odd
+since the functions make it impossible to distinguish a general
+failure from a failure due to end-of-file; the requirement is
+also in conflict with all major implementation which set both
+eofbit and failbit):
+    
    
+    
        int_type get();
+    
    
+    
        basic_istream<charT, traits>&
+    get (char_type&);
+    
    
+    
    
+These functions only set failbit of they extract no characters,
+otherwise they don't set any bits, even on failure (I find this
+inconsistency quite unexpected; the requirement is also in
+conflict with all major implementations which set eofbit
+whenever they encounter end-of-file):
+    
    
+    
        basic_istream<charT, traits>&
+    get (basic_streambuf<charT, traits>&, char_type);
+    
    
+    
        basic_istream<charT, traits>&
+    get (basic_streambuf<charT, traits>&);
+    
    
+    
    
+This function sets no bits (all implementations except for
+STLport and Classic Iostreams set eofbit when they encounter
+end-of-file):
+    
    
+    
        int_type peek ();
+    
    
+
    Informally, what we want is a global statement of intent saying
+  that eofbit gets set if we trip across EOF, and then we can take
+  away the specific wording for individual functions.  A full review
+  is necessary.  The wording currently in the standard is a mishmash,
+  and changing it on an individual basis wouldn't make things better.
+  Dietmar will do this work.
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
+Moved to NAD.  See 27.7.1.1 [istream] p3.
+
    
+
+
+
+
    Proposed resolution:
    
 
 
 
 
 
    
-
    433. Contradiction in specification of unexpected()
    
-
    Section: 18.8.2.4 [unexpected] Status: NAD
- Submitter: Vyatcheslav Sysoltsev Opened: 2003-09-29  Last modified: 2006-12-27
    
+
    399. volations of unformatted input function requirements
    
+
    Section: 27.7.1.3 [istream.unformatted] Status: NAD
+ Submitter: Martin Sebor Opened: 2003-01-05  Last modified: 2006-12-27
    
+
    View all other issues in [istream.unformatted].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
-
    
-Clause 15.5.2 [except.unexpected] paragraph 1 says that "void unexpected();
-is called (18.7.2) immediately after completing the stack unwinding
-for the former function", but 18.7.2.4 (Effects) says that "void
-unexpected(); . . . Calls the unexpected_handler function in effect
-immediately after evaluating the throwexpression (18.7.2.2),".  Isn't
-here a contradiction: 15.5.2 requires stack have been unwound when in
-void unexpected() and therefore in unexpected_handler but 18.7.2.4
-claims that unexpected_handler is called "in effect immediately" after
-evaluation of throw expression is finished, so there is no space left
-for stack to be unwound therefore?  I think the phrase "in effect
-immediately" should be removed from the standard because it brings
-ambiguity in understanding.
-
    
-
+    
    
+The Effects clauses for the two functions below violate the
+general requirements on unformatted input functions outlined
+in 27.6.1.3: they do not begin by constructing a sentry object.
+Instead, they begin by calling widen ('\n'), which may throw
+an exception. The exception is then allowed to propagate from
+the unformatted input function irrespective of the setting of
+exceptions().
+    
    
+    
    
+Note that in light of 27.6.1.1, p3 and p4, the fact that the
+functions allow exceptions thrown from widen() to propagate
+may not strictly speaking be a defect (but the fact that the
+functions do not start by constructing a sentry object still
+is). However, since an exception thrown from ctype<charT>
+::widen() during any other input operation (say, from within
+a call to num_get<charT>::get()) will be caught and cause
+badbit to be set, these two functions should not be treated
+differently for the sake of consistency.
+    
    
+  
 
 
    Proposed resolution:
    
 
 
 
    Rationale:
    
-
    There is no contradiction.  The phrase "in effect immediately" is
-  just to clarify which handler is to be called.
    
+
    
+Not a defect.  The standard is consistent, and the behavior required
+by the standard is unambiguous.  Yes, it's theoretically possible for
+widen to throw.  (Not that this will happen for the default ctype
+facet or for most real-world replacement ctype facets.)  Users who
+define ctype facets that can throw, and who care about this behavior,
+can use alternative signatures that don't call widen.
+
    
+
 
 
 
 
 
 
    
-
    437. Formatted output of function pointers is confusing
    
-
    Section: 27.7.2.6.2 [ostream.inserters.arithmetic] Status: NAD
- Submitter: Ivan Godard Opened: 2003-10-24  Last modified: 2006-12-27
    
-
    View all other issues in [ostream.inserters.arithmetic].
    
+
    417. what does ctype::do_widen() return on failure
    
+
    Section: 22.4.1.1.2 [locale.ctype.virtuals] Status: NAD
+ Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2009-07-14
    
+
    View all other issues in [locale.ctype.virtuals].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-Given:
+The Effects and Returns clauses of the do_widen() member function of
+the ctype facet fail to specify the behavior of the function on failure.
+That the function may not be able to simply cast the narrow character
+argument to the type of the result since doing so may yield the wrong value
+for some wchar_t encodings. Popular implementations of ctype<wchar_t> that
+use mbtowc() and UTF-8 as the native encoding (e.g., GNU glibc) will fail
+when the argument's MSB is set. There is no way for the the rest of locale
+and iostream to reliably detect this failure. 
 
    
-
    void f(int) {}
-void(*g)(int) = f;
-cout << g;
-
    
+
    [Kona: This is a real problem.  Widening can fail.  It's unclear
+  what the solution should be.  Returning WEOF works for the wchar_t
+  specialization, but not in general.  One option might be to add a
+  default, like narrow.  But that's an incompatible change.
+  Using traits::eof might seem like a good idea, but facets
+  don't have access to traits (a recurring problem).  We could
+  have widen throw an exception, but that's a scary option;
+  existing library components aren't written with the assumption
+  that widen can throw.]
    
 
-
    
-(with the expected #include and usings), the value printed is a rather
-surprising "true". Rather useless too.
-
    
 
-
    The standard defines:
    
+
    [
+2009-07 Frankfurt
+]
    
 
-
    ostream& operator<<(ostream&, void*);
    
 
-
    which picks up all data pointers and prints their hex value, but does
-not pick up function pointers because there is no default conversion
-from function pointer to void*. Absent that, we fall back to legacy
-conversions from C and the function pointer is converted to bool.
-
    
+
    
+NAD. The behavior is specified for all of the facets that an
+implementation is required to provide, for the basic character set.
+
    
 
-
    There should be an analogous inserter that prints the address of a
-  function pointer.
    
 
 
 
    Proposed resolution:
    
 
 
-
    Rationale:
    
-
    This is indeed a wart, but there is no good way to solve it.  C
-  doesn't provide a portable way of outputting the address of a
-  function point either.
    
-
-
-
 
 
 
    
-
    439. Should facets be copyable?
    
-
    Section: 22.4 [locale.categories] Status: NAD
- Submitter: Matt Austern Opened: 2003-11-02  Last modified: 2006-12-27
    
-
    View other active issues in [locale.categories].
    
-
    View all other issues in [locale.categories].
    
+
    418. exceptions thrown during iostream cleanup
    
+
    Section: 27.5.2.1.6 [ios::Init] Status: NAD
+ Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2009-07-14
    
+
    View all other issues in [ios::Init].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
-
    The following facets classes have no copy constructors described in
-  the standard, which, according to the standard, means that they are
-  supposed to use the compiler-generated defaults.  Default copy
-  behavior is probably inappropriate.  We should either make these
-  classes uncopyable or else specify exactly what their constructors do.
    
+
    
+The dtor of the ios_base::Init object is supposed to call flush() on the
+6 standard iostream objects cout, cerr, clog, wcout, wcerr, and wclog.
+This call may cause an exception to be thrown.
+
    
 
-
    Related issue: 421.
    
+
    
+17.4.4.8, p3 prohibits all library destructors from throwing exceptions.
+
    
 
-
            ctype_base
-        ctype
-        ctype_byname
-        ctype<char>
-        ctype_byname<char>
-        codecvt_base
-        codecvt
-        codecvt_byname
-        num_get
-        num_put
-        numpunct
-        numpunct_byname
-        collate
-        collate_byname
-        time_base
-        time_get
-        time_get_byname
-        time_put
-        time_put_byname
-        money_get
-        money_put
-        money_base
-        moneypunct
-        moneypunct_byname
-        messages_base
-        messages
-        messages_byname
-
    
+
    
+The question is: What should this dtor do if one or more of these calls
+to flush() ends up throwing an exception? This can happen quite easily
+if one of the facets installed in the locale imbued in the iostream
+object throws.
+
    
+
    [Kona: We probably can't do much better than what we've got, so
+  the LWG is leaning toward NAD.  At the point where the standard
+  stream objects are being cleaned up, the usual error reporting
+  mechanism are all unavailable.  And exception from flush at this
+  point will definitely cause problems.  A quality implementation
+  might reasonably swallow the exception, or call abort, or do
+  something even more drastic.]
    
 
 
+
    [
+See 397 and 622 for related issues.
+]
    
 
-
    Proposed resolution:
    
 
+
    [
+2009-07 Frankfurt
+]
    
 
-
    Rationale:
    
-
    The copy constructor in the base class is private.
    
+
+
    
+Moved to NAD, no consensus for change.
+
    
 
 
 
+
    Proposed resolution:
    
+
+
 
 
 
    
-
    440. Should std::complex use unqualified transcendentals?
    
-
    Section: 26.4.8 [complex.transcendentals] Status: NAD
- Submitter: Matt Austern Opened: 2003-11-05  Last modified: 2009-03-21
    
+
    421. is basic_streambuf copy-constructible?
    
+
    Section: 27.6.2.1 [streambuf.cons] Status: NAD
+ Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2009-07-14
    
+
    View all other issues in [streambuf.cons].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-Operations like pow and exp on
-complex<T> are typically implemented in terms of
-operations like sin and cos on T.  
-Should implementations write this as std::sin, or as plain
-unqualified sin?
+The reflector thread starting with c++std-lib-11346 notes that the class
+template basic_streambuf, along with basic_stringbuf and basic_filebuf,
+is copy-constructible but that the semantics of the copy constructors
+are not defined anywhere. Further, different implementations behave
+differently in this respect: some prevent copy construction of objects
+of these types by declaring their copy ctors and assignment operators
+private, others exhibit undefined behavior, while others still give
+these operations well-defined semantics.
 
    
 
-
    The issue, of course, is whether we want to use
-argument-dependent lookup in the case where T is a
-user-defined type.  This is similar to the issue of valarray
-transcendentals, as discussed in issue 226.
    
-
-
    This issue differs from valarray transcendentals in two important
-ways.  First, "the effect of instantiating the template
-complex for types other than float, double or long double is
-unspecified." (26.4.1 [complex.syn]) Second, the standard does not
-dictate implementation, so there is no guarantee that a particular
-real math function is used in the implementation of a particular
-complex function.
    
+
    
+Note that this problem doesn't seem to be isolated to just the three
+types mentioned above. A number of other types in the library section
+of the standard provide a compiler-generated copy ctor and assignment
+operator yet fail to specify their semantics.  It's believed that the
+only types for which this is actually a problem (i.e. types where the
+compiler-generated default may be inappropriate and may not have been
+intended) are locale facets.  See issue 439.
+
    
 
+
    [
+2009-07 Frankfurt
+]
    
 
 
-
    Proposed resolution:
    
+
    
+NAD. Option B is already in the Working Draft.
+
    
 
 
-
    Rationale:
    
-
    If you instantiate std::complex for user-defined types, all bets
-are off.
    
 
+
    Proposed resolution:
    
+
    
+27.5.2 [lib.streambuf]:  Add into the synopsis, public section, just above the destructor declaration:
+
    
 
+
    
+
    basic_streambuf(const basic_streambuf& sb);
+basic_streambuf& operator=(const basic_streambuf& sb);
+
    
+
    
 
+
    Insert after 27.5.2.1, paragraph 2:
    
+
    
+
    basic_streambuf(const basic_streambuf& sb);
+
    
 
+
    Constructs a copy of sb.
    
+
    Postcondtions:
    
+
                    eback() == sb.eback()
+                gptr()  == sb.gptr()
+                egptr() == sb.egptr()
+                pbase() == sb.pbase()
+                pptr()  == sb.pptr()
+                epptr() == sb.epptr()
+                getloc() == sb.getloc()
+
    
 
-
    
-
    447. Wrong template argument for time facets
    
-
    Section: 22.3.1.1.1 [locale.category] Status: Dup
- Submitter: Pete Becker Opened: 2003-12-26  Last modified: 2007-01-15
    
-
    View all other issues in [locale.category].
    
-
    View all issues with Dup status.
    
-
    Duplicate of: 327
    
-
    Discussion:
    
-
    
-22.1.1.1.1/4, table 52, "Required Instantiations", lists, among others:
-
    
-
        time_get<char,InputIterator>
-    time_get_byname<char,InputIterator>
-    time_get<wchar_t,OutputIterator>
-    time_get_byname<wchar_t,OutputIterator>
+
    basic_streambuf& operator=(const basic_streambuf& sb);
 
    
 
-
    
-The second argument to the last two should be InputIterator, not
-OutputIterator.
-
    
+
    Assigns the data members of sb to this.
    
 
+
    Postcondtions:
    
+
                    eback() == sb.eback()
+                gptr()  == sb.gptr()
+                egptr() == sb.egptr()
+                pbase() == sb.pbase()
+                pptr()  == sb.pptr()
+                epptr() == sb.epptr()
+                getloc() == sb.getloc()
+
    
 
-
    Proposed resolution:
    
-
    
-Change the second template argument to InputIterator.
-
    
+
    Returns: *this.
    
+
    
 
+
    27.7.1 [lib.stringbuf]:
    
 
-
    Rationale:
    
+
    Option A:
    
 
+
    
+
    Insert into the basic_stringbuf synopsis in the private section:
    
 
+
    basic_stringbuf(const basic_stringbuf&);             // not defined
+basic_stringbuf& operator=(const basic_stringbuf&);  // not defined
+
    
+
    
 
+
    Option B:
    
 
+
    
+
    Insert into the basic_stringbuf synopsis in the public section:
    
 
+
    basic_stringbuf(const basic_stringbuf& sb);
+basic_stringbuf& operator=(const basic_stringbuf& sb);
+
    
 
-
    
-
    450. set::find is inconsistent with associative container requirements
    
-
    Section: 23.4.3 [set] Status: Dup
- Submitter: Bill Plauger Opened: 2004-01-30  Last modified: 2009-05-01
    
-
    View all other issues in [set].
    
-
    View all issues with Dup status.
    
-
    Duplicate of: 214
    
-
    Discussion:
    
-
    map/multimap have:
    
+
    27.7.1.1, insert after paragraph 4:
    
 
-
        iterator find(const key_type& x) const;
-    const_iterator find(const key_type& x) const;
-
    
+
    basic_stringbuf(const basic_stringbuf& sb);
    
 
 
    
-which is consistent with the table of associative container requirements.
-But set/multiset have:
+Constructs an independent copy of sb as if with sb.str(), and with the openmode that sb was constructed with.
 
    
-
        iterator find(const key_type&) const;
+
+
    Postcondtions: 
    
+
                   str() == sb.str()
+               gptr()  - eback() == sb.gptr()  - sb.eback()
+               egptr() - eback() == sb.egptr() - sb.eback()
+               pptr()  - pbase() == sb.pptr()  - sb.pbase()
+               getloc() == sb.getloc()
 
    
 
-
    
-set/multiset should look like map/multimap, and honor the requirements
-table, in this regard.
+
    Note: The only requirement on epptr() is that it point beyond the
+initialized range if an output sequence exists. There is no requirement
+that epptr() - pbase() == sb.epptr() - sb.pbase().
 
    
 
+
    basic_stringbuf& operator=(const basic_stringbuf& sb);
    
+
    After assignment the basic_stringbuf has the same state as if it
+were initially copy constructed from sb, except that the
+basic_stringbuf is allowed to retain any excess capacity it might have,
+which may in turn effect the value of epptr().
+
    
+
    
 
-
    Proposed resolution:
    
-
-
-
    Rationale:
    
-
-
+
    27.8.1.1 [lib.filebuf]
    
 
+
    Insert at the bottom of the basic_filebuf synopsis:
    
 
+
    
+
    private:
+  basic_filebuf(const basic_filebuf&);             // not defined
+  basic_filebuf& operator=(const basic_filebuf&);  // not defined
+
    
+
    
+
    [Kona: this is an issue for basic_streambuf itself and for its
+  derived classes.  We are leaning toward allowing basic_streambuf to
+  be copyable, and specifying its precise semantics.  (Probably the
+  obvious: copying the buffer pointers.)  We are less sure whether
+  the streambuf derived classes should be copyable.  Howard will
+  write up a proposal.]
    
+
+
+
    [Sydney: Dietmar presented a new argument against basic_streambuf
+  being copyable: it can lead to an encapsulation violation. Filebuf
+  inherits from streambuf. Now suppose you inhert a my_hijacking_buf
+  from streambuf. You can copy the streambuf portion of a filebuf to a
+  my_hijacking_buf, giving you access to the pointers into the
+  filebuf's internal buffer. Perhaps not a very strong argument, but
+  it was strong enough to make people nervous. There was weak
+  preference for having streambuf not be copyable. There was weak
+  preference for having stringbuf not be copyable even if streambuf
+  is. Move this issue to open for now.
+]
    
 
 
-
    
-
    451. Associative erase should return an iterator
    
-
    Section: 23.2.4 [associative.reqmts], 23.4 [associative] Status: Dup
- Submitter: Bill Plauger Opened: 2004-01-30  Last modified: 2009-05-01
    
-
    View other active issues in [associative.reqmts].
    
-
    View all other issues in [associative.reqmts].
    
-
    View all issues with Dup status.
    
-
    Duplicate of: 130
    
-
    Discussion:
    
-
    map/multimap/set/multiset have:
    
-
        void erase(iterator);
-    void erase(iterator, iterator);
-
    
+
    [
+2007-01-12, Howard:
+Rvalue Reference Recommendations for Chapter 27
+recommends protected copy constructor and assignment for basic_streambuf with the same semantics
+as would be generated by the compiler.  These members aid in derived classes implementing move semantics.
+A protected copy constructor and copy assignment operator do not expose encapsulation more so than it is
+today as each data member of a basic_streambuf is already both readable and writable by derived
+classes via various get/set protected member functions (eback(), setp(), etc.).  Rather
+a protected copy constructor and copy assignment operator simply make the job of derived classes implementing
+move semantics less tedious and error prone.
+]
    
 
-
    But there's no good reason why these can't return an iterator, as for
-vector/deque/list:
    
-
        iterator erase(iterator);
-    iterator erase(iterator, iterator);
-
    
 
 
 
-
    Proposed resolution:
    
+
    Rationale:
    
 
    
-Informally: The table of associative container requirements, and the
-relevant template classes, should return an iterator designating the
-first element beyond the erased subrange.
+27.5.2 [lib.streambuf]: The proposed basic_streambuf copy constructor
+and assignment operator are the same as currently implied by the lack
+of declarations: public and simply copies the data members.  This
+resolution is not a change but a clarification of the current
+standard.
 
    
 
+
    
+27.7.1 [lib.stringbuf]: There are two reasonable options: A) Make
+basic_stringbuf not copyable.  This is likely the status-quo of
+current implementations.  B) Reasonable copy semantics of
+basic_stringbuf can be defined and implemented.  A copyable
+basic_streambuf is arguably more useful than a non-copyable one.  This
+should be considered as new functionality and not the fixing of a
+defect.  If option B is chosen, ramifications from issue 432 are taken
+into account.
+
    
 
-
    Rationale:
    
+
    
+27.8.1.1 [lib.filebuf]: There are no reasonable copy semantics for
+basic_filebuf.
+
    
 
 
 
@@ -5871,606 +7339,493 @@ first element beyond the erased subrange.
 
 
 
    
-
    452.  locale::combine should be permitted to generate a named locale
    
-
    Section: 22.3.1.3 [locale.members] Status: NAD
- Submitter: Bill Plauger Opened: 2004-01-30  Last modified: 2009-05-01
    
-
    View all other issues in [locale.members].
    
-
    View all issues with NAD status.
    
+
    423. effects of negative streamsize in iostreams
    
+
    Section: 27 [input.output] Status: NAD Future
+ Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2009-07-14
    
+
    View all other issues in [input.output].
    
+
    View all issues with NAD Future status.
    
 
    Discussion:
    
-
    template<class Facet>
-    locale::combine(const locale&) const;
-
    
+
 
    
-is obliged to create a locale that has no name. This is overspecification
-and overkill. The resulting locale should follow the usual rules -- it
-has a name if the locale argument has a name and Facet is one of the
-standard facets.
+A third party test suite tries to exercise istream::ignore(N) with
+a negative value of N and expects that the implementation will treat
+N as if it were 0. Our implementation asserts that (N >= 0) holds and
+aborts the test.
+
    
+
+
    
+I can't find anything in section 27 that prohibits such values but I don't
+see what the effects of such calls should be, either (this applies to
+a number of unformatted input functions as well as some member functions
+of the basic_streambuf template).
 
    
 
 
    [
- Sydney and post-Sydney (see c++std-lib-13439, c++std-lib-13440,
- c++std-lib-13443): agreed that it's overkill to say that the locale
- is obligated to be nameless.  However, we also can't require it to
- have a name.  At the moment, locale names are based on categories
- and not on individual facets.  If a locale contains two different
- facets of different names from the same category, then this would
- not fit into existing naming schemes.  We need to give
- implementations more freedom.  Bill will provide wording.
+2009-07 Frankfurt
 ]
    
 
 
+
    
+
    
+This is related to LWG 255.
+
    
+
    
+Move to NAD Future.
+
    
+
    
+
+
 
+
    Proposed resolution:
    
+
    
+I propose that we add to each function in clause 27 that takes an argument,
+say N, of type streamsize a Requires clause saying that "N >= 0." The intent
+is to allow negative streamsize values in calls to precision() and width()
+but disallow it in calls to streambuf::sgetn(), istream::ignore(), or
+ostream::write().
+
    
+
+
    [Kona: The LWG agreed that this is probably what we want.  However, we
+  need a review to find all places where functions in clause 27 take
+  arguments of type streamsize that shouldn't be allowed to go
+  negative.  Martin will do that review.]
    
 
-
    Rationale:
    
-
    After further discussion the LWG decided to close this as NAD.
-  The fundamental problem is that names right now are per-category,
-  not per-facet.  The combine member function works at the
-  wrong level of granularity.
    
 
 
 
 
 
 
    
-
    454. basic_filebuf::open should accept wchar_t names
    
-
    Section: 27.9.1.4 [filebuf.members] Status: NAD
- Submitter: Bill Plauger Opened: 2004-01-30  Last modified: 2009-05-01
    
-
    View all other issues in [filebuf.members].
    
-
    View all issues with NAD status.
    
-
    Duplicate of: 105
    
+
    424. normative notes
    
+
    Section: 17.5.1.2 [structure.summary] Status: NAD Editorial
+ Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2009-07-13
    
+
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
-
        basic_filebuf *basic_filebuf::open(const char *, ios_base::open_mode);
-
    
 
-
    should be supplemented with the overload:
    
+
    
+The text in 17.3.1.1, p1 says:
+
    
 
-
        basic_filebuf *basic_filebuf::open(const wchar_t *, ios_base::open_mode);
-
    
+"Paragraphs labelled "Note(s):" or "Example(s):" are informative, other
+paragraphs are normative."
+
    
 
-
    
-Depending on the operating system, one of these forms is fundamental and
-the other requires an implementation-defined mapping to determine the
-actual filename.
+The library section makes heavy use of paragraphs labeled "Notes(s),"
+some of which are clearly intended to be normative (see list 1), while
+some others are not (see list 2). There are also those where the intent
+is not so clear (see list 3).
+

    
+
+List 1 -- Examples of (presumably) normative Notes:
+
    
+
+20.8.4.1 [allocator.members], p3,
    
+20.8.4.1 [allocator.members], p10,
    
+21.4.2 [string.cons], p11,
    
+22.3.1.2 [locale.cons], p11,
    
+23.3.2.3 [deque.modifiers], p2,
    
+25.5.7 [alg.min.max], p3,
    
+26.4.6 [complex.ops], p15,
    
+27.6.2.4.3 [streambuf.virt.get], p7.
    
+
    
+
+List 2 -- Examples of (presumably) informative Notes:
+
    
+
+18.6.1.3 [new.delete.placement], p3,
    
+21.4.6.6 [string::replace], p14,
    
+22.4.1.4.2 [locale.codecvt.virtuals], p3,
    
+25.3.4 [alg.foreach], p4,
    
+26.4.5 [complex.member.ops], p1,
    
+27.5.2.5 [ios.base.storage], p6.
    
+
    
+
+List 3 -- Examples of Notes that are not clearly either normative
+or informative:
+
    
+
+22.3.1.2 [locale.cons], p8,
    
+22.3.1.5 [locale.statics], p6,
    
+27.6.2.4.5 [streambuf.virt.put], p4.
    
+
    
+
+None of these lists is meant to be exhaustive.
 
    
 
-
    [Sydney: Yes, we want to allow wchar_t filenames.  Bill will
-  provide wording.]
    
+
    [Definitely a real problem.  The big problem is there's material
+  that doesn't quite fit any of the named paragraph categories
+  (e.g. Effects).  Either we need a new kind of named
+  paragraph, or we need to put more material in unnamed paragraphs
+  jsut after the signature.  We need to talk to the Project Editor
+  about how to do this.
+]
    
 
 
 
    [
-In Toronto we noted that this is issue 5 from
-N1569.
+Bellevue: Specifics of list 3: First 2 items correct in std (22.1.1.2,
+22.1.1.5) Third item should be non-normative (27.5.2.4.5), which Pete
+will handle editorially.
 ]
    
 
-
    
-How does this interact with the newly-defined character types, and how
-do we avoid interface explosion considering std::string overloads that
-were added? Propose another solution that is different than the
-suggestion proposed by PJP.
-
    
-
    
-Suggestion is to make a member template function for basic_string (for
-char, wchar_t, u16char, u32char instantiations), and then just keep a
-const char* member.
-
    
-
    
-Goal is to do implicit conversion between character string literals to
-appropriate basic_string type. Not quite sure if this is possible.
-
    
-
    
-Implementors are free to add specific overloads for non-char character
-types.
-
    
 
 
    [
-Martin adds pre-Sophia Antipolis:
+post San Francisco:  Howard: reopened, needs attention.
 ]
    
 
 
-
    
-Please see issue 454: problems and solutions.
-
    
+
    [Pete: I changed the paragraphs marked "Note" and "Notes" to use "Remark" and "Remarks".
+Fixed as editorial.  This change has been in the WD since the post-Redmond mailing, in 2004.
+Recommend NAD.]
    
+
 
 
    [
-Sophia Antipolis:
+Batavia:  We feel that the references in List 2 above should be changed from Remarks
+to Notes.  We also feel that those items in List 3 need to be double checked for
+the same change.  Alan and Pete to review.
 ]
    
 
 
+
    [
+Batavia (2009-05):
+]
    
+
 
    
 
    
-Beman is concerned that making these changes to basic_filebuf is not
-usefully changed unless fstream is also changed; this also only handles
-wchar_t and not other character types.
+A spot-check of List 2 suggests the issue is still relevant,
+and a review of List 3 still seems called-for.
 
    
 
    
-The TR2 filesystem library is a more complete solution, but is not available soon.
+Move to NAD Editorial.
 
    
 
    
 
-
    [
-Martin adds:  please reference
-N2683 for
-problems and solutions.
-]
    
-
-
 
 
 
    Proposed resolution:
    
 
-
    Change from:
    
-
    
-
    basic_filebuf<charT,traits>* open(
-    const char* s,
-    ios_base::openmode mode );
-
    
 
-
    
-Effects: If is_open() != false, returns a null pointer.
-Otherwise, initializes the filebuf as required. It then
-opens a file, if possible, whose name is the NTBS s ("as if"
-by calling std::fopen(s,modstr)).
    
-
    
 
-
    to:
    
 
-
    
-
    basic_filebuf<charT,traits>* open(
-    const char* s,
-    ios_base::openmode mode );
+
    
+
    429. typo in basic_ios::clear(iostate)
    
+
    Section: 27.5.4.3 [iostate.flags] Status: Dup
+ Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2006-12-30
    
+
    View all other issues in [iostate.flags].
    
+
    View all issues with Dup status.
    
+
    Duplicate of: 412
    
+
    Discussion:
    
+        
    
 
-basic_filebuf<charT,traits>* open(
-    const wchar_t* ws,
-    ios_base::openmode mode );
-
    
+The Effects clause in 27.4.4.3, p5 describing the effects of a call to
+the ios_base member function clear(iostate state) says that the function
+only throws if the respective bits are already set prior to the function
+call. That's obviously not the intent. If it was, a call to clear(badbit)
+on an object for which (rdstate() == goodbit && exceptions() == badbit)
+holds would not result in an exception being thrown.
 
-
    
-Effects: If is_open() != false, returns a null pointer.
-Otherwise, initializes the filebuf as required. It then
-opens a file, if possible, whose name is the NTBS s ("as if"
-by calling std::fopen(s,modstr)).
-For the second signature, the NTBS s is determined from the
-WCBS ws in an implementation-defined manner.
-
    
+        
    
+    
+    
    Proposed resolution:
    
+        
    
 
-
    
-(NOTE: For a system that "naturally" represents a filename
-as a WCBS, the NTBS s in the first signature may instead
-be mapped to a WCBS; if so, it follows the same mapping
-rules as the first argument to open.)
-
    
-
    
+The text ought to be changed from
+
    
+
+"If (rdstate() & exceptions()) == 0, returns. ..."
+
    
 
+to
+
    
+
+"If (state & exceptions()) == 0, returns. ..."
+        
    
 
 
 
    Rationale:
    
-
    
-Slightly controversial, but by a 7-1 straw poll the LWG agreed to move
-this to Ready.  The controversy was because the mapping between wide
-names and files in a filesystem is implementation defined.  The
-counterargument, which most but not all LWG members accepted, is that
-the mapping between narrow files names and files is also
-implemenation defined.
    
 
-
    [Lillehammer: Moved back to "open" status, at Beman's urging.
-(1) Why just basic_filebuf, instead of also basic_fstream (and
-possibly other things too). (2) Why not also constructors that take
-std::basic_string? (3) We might want to wait until we see Beman's
-filesystem library; we might decide that it obviates this.]
    
 
 
-
    [
-post Bellevue:
-]
    
 
 
-
    
-
    
-Move again to Ready.
-
    
-
    
-There is a timing issue here. Since the filesystem library will not be
-in C++0x, this should be brought forward. This solution would remain
-valid in the context of the proposed filesystem.
-
    
-
    
-This issue has been kicking around for a while, and the wchar_t addition
-alone would help many users. Thus, we suggest putting this on the
-reflector list with an invitation for someone to produce proposed
-wording that covers basic_fstream. In the meantime, we suggest that the
-proposed wording be adopted as-is.
-
    
+
+
    
+
    433. Contradiction in specification of unexpected()
    
+
    Section: 18.8.2.4 [unexpected] Status: NAD
+ Submitter: Vyatcheslav Sysoltsev Opened: 2003-09-29  Last modified: 2006-12-27
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
    
-If more of the Lillehammer questions come back, they should be
-introduced as separate issues.
+Clause 15.5.2 [except.unexpected] paragraph 1 says that "void unexpected();
+is called (18.7.2) immediately after completing the stack unwinding
+for the former function", but 18.7.2.4 (Effects) says that "void
+unexpected(); . . . Calls the unexpected_handler function in effect
+immediately after evaluating the throwexpression (18.7.2.2),".  Isn't
+here a contradiction: 15.5.2 requires stack have been unwound when in
+void unexpected() and therefore in unexpected_handler but 18.7.2.4
+claims that unexpected_handler is called "in effect immediately" after
+evaluation of throw expression is finished, so there is no space left
+for stack to be unwound therefore?  I think the phrase "in effect
+immediately" should be removed from the standard because it brings
+ambiguity in understanding.
 
    
-
    
-
-
    [
-San Francisco:
-]
    
 
 
-
    
-Some existing implementations provide overload already. Expected
-filesystem "path" object overloads neatly, without surprises; implying
-NAD.
-
    
+
    Proposed resolution:
    
 
 
+
    Rationale:
    
+
    There is no contradiction.  The phrase "in effect immediately" is
+  just to clarify which handler is to be called.
    
 
 
 
 
 
 
    
-
    462. Destroying objects with static storage duration
    
-
    Section: 3.6.3 [basic.start.term], 18.4 [cstdint] Status: NAD
- Submitter: Bill Plauger Opened: 2004-03-23  Last modified: 2008-02-25
    
+
    437. Formatted output of function pointers is confusing
    
+
    Section: 27.7.2.6.2 [ostream.inserters.arithmetic] Status: NAD
+ Submitter: Ivan Godard Opened: 2003-10-24  Last modified: 2006-12-27
    
+
    View all other issues in [ostream.inserters.arithmetic].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-3.6.3 Termination spells out in detail the interleaving of static
-destructor calls and calls to functions registered with atexit. To
-match this behavior requires intimate cooperation between the code
-that calls destructors and the exit/atexit machinery. The former
-is tied tightly to the compiler; the latter is a primitive mechanism
-inherited from C that traditionally has nothing to do with static
-construction and destruction. The benefits of intermixing destructor
-calls with atexit handler calls is questionable at best, and very
-difficult to get right, particularly when mixing third-party C++
-libraries with different third-party C++ compilers and C libraries
-supplied by still other parties.
+Given:
 
    
+
    void f(int) {}
+void(*g)(int) = f;
+cout << g;
+
    
 
 
    
-I believe the right thing to do is defer all static destruction
-until after all atexit handlers are called. This is a change in
-behavior, but one that is likely visible only to perverse test
-suites. At the very least, we should permit deferred destruction
-even if we don't require it.
+(with the expected #include and usings), the value printed is a rather
+surprising "true". Rather useless too.
 
    
 
-
    [If this is to be changed, it should probably be changed by CWG.
-  At this point, however, the LWG is leaning toward NAD.  Implementing
-  what the standard says is hard work, but it's not impossible and
-  most vendors went through that pain years ago.  Changing this
-  behavior would be a user-visible change, and would break at least
-  one real application.]
    
-
-
-
    [
-Batavia:  Send to core with our recommendation that we should permit deferred
-destruction but not require it.
-]
    
-
-
-
    [
-Howard:  The course of action recommended in Batavia would undo LWG
-issue 3 and break current code implementing the "phoenix
-singleton". Search the net for "phoenix singleton atexit" to get a feel
-for the size of the adverse impact this change would have.  Below is
-sample code which implements the phoenix singleton and would break if
-atexit is changed in this way:
-]
    
-
-
-
    #include <cstdlib>
-#include <iostream>
-#include <type_traits>
-#include <new>
-
-class A
-{
-    bool alive_;
-    A(const A&);
-    A& operator=(const A&);
-public:
-    A() : alive_(true) {std::cout << "A()\n";}
-    ~A() {alive_ = false; std::cout << "~A()\n";}
-    void use()
-    {
-        if (alive_)
-            std::cout << "A is alive\n";
-        else
-            std::cout << "A is dead\n";
-    }
-};
-
-void deallocate_resource();
-
-// This is the phoenix singleton pattern
-A& get_resource(bool create = true)
-{
-    static std::aligned_storage<sizeof(A), std::alignment_of<A>::value>::type buf;
-    static A* a;
-    if (create)
-    {
-        if (a != (A*)&buf)
-        {
-            a = ::new (&buf) A;
-            std::atexit(deallocate_resource);
-        }
-    }
-    else
-    {
-        a->~A();
-        a = (A*)&buf + 1;
-    }
-    return *a;
-}
-
-void deallocate_resource()
-{
-    get_resource(false);
-}
-
-void use_A(const char* message)
-{
-    A& a = get_resource();
-    std::cout << "Using A " << message << "\n";
-    a.use();
-}
-
-struct B
-{
-    ~B() {use_A("from ~B()");}
-};
-
-B b;
+
    The standard defines:
    
 
-int main()
-{
-    use_A("from main()");
-}
-
    
+
    ostream& operator<<(ostream&, void*);
    
 
-
    
-The correct output is:
+
    which picks up all data pointers and prints their hex value, but does
+not pick up function pointers because there is no default conversion
+from function pointer to void*. Absent that, we fall back to legacy
+conversions from C and the function pointer is converted to bool.
 
    
 
-
    A()
-Using A from main()
-A is alive
-~A()
-A()
-Using A from ~B()
-A is alive
-~A()
-
    
-
-
    [
-Bellevue: Confirmed no interaction with quick_exit.
-Strong feeling against mandating the change. Leaning towards NAD rather than permitting the change,
-as this would make common implementations of pheonix-singleton pattern implementation defined, as noted by Howard.
-Bill agrees issue is no longer serious, and accepts NAD.
-]
    
+
    There should be an analogous inserter that prints the address of a
+  function pointer.
    
 
 
+
    Proposed resolution:
    
 
 
-
    Proposed resolution:
    
-
    
-
    
+
    Rationale:
    
+
    This is indeed a wart, but there is no good way to solve it.  C
+  doesn't provide a portable way of outputting the address of a
+  function point either.
    
 
 
 
 
 
 
    
-
    470. accessing containers from their elements' special functions
    
-
    Section: 23 [containers] Status: NAD
- Submitter: Martin Sebor Opened: 2004-06-28  Last modified: 2007-04-18
    
-
    View other active issues in [containers].
    
-
    View all other issues in [containers].
    
+
    439. Should facets be copyable?
    
+
    Section: 22.4 [locale.categories] Status: NAD
+ Submitter: Matt Austern Opened: 2003-11-02  Last modified: 2006-12-27
    
+
    View all other issues in [locale.categories].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
+
    The following facets classes have no copy constructors described in
+  the standard, which, according to the standard, means that they are
+  supposed to use the compiler-generated defaults.  Default copy
+  behavior is probably inappropriate.  We should either make these
+  classes uncopyable or else specify exactly what their constructors do.
    
 
-
    
-The standard doesn't prohibit the destructors (or any other special
-functions) of containers' elements invoked from a member function
-of the container from "recursively" calling the same (or any other)
-member function on the same container object, potentially while the
-container is in an intermediate state, or even changing the state
-of the container object while it is being modified. This may result
-in some surprising (i.e., undefined) behavior.
-
    
+
    Related issue: 421.
    
 
-
    Read email thread starting with c++std-lib-13637 for more.
    
+
            ctype_base
+        ctype
+        ctype_byname
+        ctype<char>
+        ctype_byname<char>
+        codecvt_base
+        codecvt
+        codecvt_byname
+        num_get
+        num_put
+        numpunct
+        numpunct_byname
+        collate
+        collate_byname
+        time_base
+        time_get
+        time_get_byname
+        time_put
+        time_put_byname
+        money_get
+        money_put
+        money_base
+        moneypunct
+        moneypunct_byname
+        messages_base
+        messages
+        messages_byname
+
    
 
 
 
 
    Proposed resolution:
    
 
-
    Add to Container Requirements the following new paragraph:
    
-
-
        Unless otherwise specified, the behavior of a program that
-    invokes a container member function f from a member function
-    g of the container's value_type on a container object c that
-    called g from its mutating member function h, is undefined.
-    I.e., if v is an element of c, directly or indirectly calling
-    c.h() from v.g() called from c.f(), is undefined.
-
    
-
-
    [Redmond: This is a real issue, but it's probably a clause 17
-  issue, not clause 23.  We get the same issue, for example, if we
-  try to destroy a stream from one of the stream's callback functions.]
    
-
-  
-
 
 
    Rationale:
    
-
    
-Recommend NAD.  We agree this is an issue, but not a defect.
-We believe that there is no wording we can put in the standard
-that will cover all cases without introducing unfortunate
-corner cases.
-
    
+
    The copy constructor in the base class is private.
    
 
 
 
 
 
 
    
-
    472. Missing "Returns" clause in std::equal_range
    
-
    Section: 25.5.3.3 [equal.range] Status: Dup
- Submitter: Prateek R Karandikar Opened: 2004-06-30  Last modified: 2006-12-30
    
-
    View all other issues in [equal.range].
    
-
    View all issues with Dup status.
    
-
    Duplicate of: 270
    
+
    440. Should std::complex use unqualified transcendentals?
    
+
    Section: 26.4.8 [complex.transcendentals] Status: NAD
+ Submitter: Matt Austern Opened: 2003-11-05  Last modified: 2009-03-21
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-There is no "Returns:" clause for std::equal_range, which returns non-void.
+Operations like pow and exp on
+complex<T> are typically implemented in terms of
+operations like sin and cos on T.  
+Should implementations write this as std::sin, or as plain
+unqualified sin?
 
    
 
+
    The issue, of course, is whether we want to use
+argument-dependent lookup in the case where T is a
+user-defined type.  This is similar to the issue of valarray
+transcendentals, as discussed in issue 226.
    
+
+
    This issue differs from valarray transcendentals in two important
+ways.  First, "the effect of instantiating the template
+complex for types other than float, double or long double is
+unspecified." (26.4.1 [complex.syn]) Second, the standard does not
+dictate implementation, so there is no guarantee that a particular
+real math function is used in the implementation of a particular
+complex function.
    
+
+
 
 
    Proposed resolution:
    
 
 
 
    Rationale:
    
-
    Fixed as part of issue 270.
    
-
+
    If you instantiate std::complex for user-defined types, all bets
+are off.
    
 
 
 
 
 
 
    
-
    476. Forward Iterator implied mutability
    
-
    Section: 24.2.4 [forward.iterators] Status: NAD
- Submitter: Dave Abrahams Opened: 2004-07-09  Last modified: 2007-01-15
    
-
    View all other issues in [forward.iterators].
    
-
    View all issues with NAD status.
    
+
    447. Wrong template argument for time facets
    
+
    Section: 22.3.1.1.1 [locale.category] Status: Dup
+ Submitter: Pete Becker Opened: 2003-12-26  Last modified: 2007-01-15
    
+
    View all other issues in [locale.category].
    
+
    View all issues with Dup status.
    
+
    Duplicate of: 327
    
 
    Discussion:
    
-
-
    24.1/3 says:
    
-
    
-  Forward iterators satisfy all the requirements of the input and
-  output iterators and can be used whenever either kind is specified
-
    
-
 
    
-The problem is that satisfying the requirements of output iterator
-means that you can always assign *something* into the result of
-dereferencing it.  That makes almost all non-mutable forward
-iterators non-conforming.  I think we need to sever the refinement
-relationship between forward iterator and output iterator.
+22.1.1.1.1/4, table 52, "Required Instantiations", lists, among others:
 
    
+
        time_get<char,InputIterator>
+    time_get_byname<char,InputIterator>
+    time_get<wchar_t,OutputIterator>
+    time_get_byname<wchar_t,OutputIterator>
+
    
 
-
    Related issue: 200.  But this is not a dup.
    
-
+
    
+The second argument to the last two should be InputIterator, not
+OutputIterator.
+
    
 
 
 
    Proposed resolution:
    
+
    
+Change the second template argument to InputIterator.
+
    
 
 
 
    Rationale:
    
-
    Yes, 24.1/3 does say that. But it's introductory material. The
-precise specification is in 24.1.3, and the requrements table there is
-right.  We don't need to fine-tune introductory wording.  (Especially
-since this wording is likely to be changed as part of the iterator
-overhaul.)
     
+
 
 
 
 
 
 
    
-
    477. Operator-> for const forward iterators
    
-
    Section: 24.2.4 [forward.iterators] Status: Dup
- Submitter: Dave Abrahams Opened: 2004-07-11  Last modified: 2007-01-15
    
-
    View all other issues in [forward.iterators].
    
+
    450. set::find is inconsistent with associative container requirements
    
+
    Section: 23.4.3 [set] Status: Dup
+ Submitter: Bill Plauger Opened: 2004-01-30  Last modified: 2009-05-01
    
+
    View all other issues in [set].
    
 
    View all issues with Dup status.
    
-
    Duplicate of: 478
    
+
    Duplicate of: 214
    
 
    Discussion:
    
-
    
-The Forward Iterator requirements table contains the following:
-
    
-
     expression  return type         operational  precondition
-                                  semantics
-  ==========  ==================  ===========  ==========================
-  a->m        U& if X is mutable, (*a).m       pre: (*a).m is well-defined.
-              otherwise const U&
+
    map/multimap have:
    
 
-  r->m        U&                  (*r).m       pre: (*r).m is well-defined.
+
        iterator find(const key_type& x) const;
+    const_iterator find(const key_type& x) const;
 
    
 
 
    
-The first line is exactly right.  The second line is wrong.  Basically
-it implies that the const-ness of the iterator affects the const-ness
-of referenced members.  But Paragraph 11 of [lib.iterator.requirements] says:
+which is consistent with the table of associative container requirements.
+But set/multiset have:
 
    
+
        iterator find(const key_type&) const;
+
    
 
-
    
-   In the following sections, a and b denote values of type const X, n
-   denotes a value of the difference type Distance, u, tmp, and m
-   denote identifiers, r denotes a value of X&, t denotes a value of
-   value type T, o denotes a value of some type that is writable to
-   the output iterator.
-
    
-
-
    AFAICT if we need the second line at all, it should read the same
-as the first line.
    
-
-
    Related issue: 478
    
+
    
+set/multiset should look like map/multimap, and honor the requirements
+table, in this regard.
+
    
 
 
 
    Proposed resolution:
    
 
 
 
    Rationale:
    
-
    The LWG agrees that this is a real problem.  Marked as a DUP
-  because the LWG chose to adopt the solution proposed in
-  478.
-
    
+
 
 
 
 
 
 
    
-
    479. Container requirements and placement new
    
-
    Section: 23.2 [container.requirements] Status: Dup
- Submitter: Herb Sutter Opened: 2004-08-01  Last modified: 2007-04-18
    
-
    View other active issues in [container.requirements].
    
-
    View all other issues in [container.requirements].
    
+
    451. Associative erase should return an iterator
    
+
    Section: 23.2.4 [associative.reqmts], 23.4 [associative] Status: Dup
+ Submitter: Bill Plauger Opened: 2004-01-30  Last modified: 2009-05-01
    
+
    View all other issues in [associative.reqmts].
    
 
    View all issues with Dup status.
    
-
    Duplicate of: 580
    
+
    Duplicate of: 130
    
 
    Discussion:
    
-
    Nothing in the standard appears to make this program ill-formed:
    
-
-
      struct C {
-    void* operator new( size_t s ) { return ::operator new( s ); }
-    // NOTE: this hides in-place and nothrow new
-  };
-
-  int main() {
-    vector<C> v;
-    v.push_back( C() );
-  }
+
    map/multimap/set/multiset have:
    
+
        void erase(iterator);
+    void erase(iterator, iterator);
 
    
 
-
    Is that intentional?  We should clarify whether or not we intended
-  to require containers to support types that define their own special
-  versions of operator new.
    
-
-
    [
-Lillehammer: A container will definitely never use this overridden
-operator new, but whether it will fail to compile is unclear from the
-standard.  Are containers supposed to use qualified or unqualified
-placement new?  20.4.1.1 is somewhat relevant, but the standard
-doesn't make it completely clear whether containers have to use
-Allocator::construct(). If containers don't use it, the details of how
-containers use placement new are unspecified. That is the real bug,
-but it needs to be fixed as part of the allocator overhaul.  Weak
-support that the eventual solution should make this code well formed.
-]
    
-
+
    But there's no good reason why these can't return an iterator, as for
+vector/deque/list:
    
+
        iterator erase(iterator);
+    iterator erase(iterator, iterator);
+
    
 
 
 
 
    Proposed resolution:
    
+
    
+Informally: The table of associative container requirements, and the
+relevant template classes, should return an iterator designating the
+first element beyond the erased subrange.
+
    
+
 
+
    Rationale:
    
 
 
 
@@ -6478,250 +7833,232 @@ support that the eventual solution should make this code well formed.
 
 
 
    
-
    480. unary_function and binary_function should have protected nonvirtual destructors
    
-
    Section: 20.7.3 [base] Status: NAD
- Submitter: Joe Gottman Opened: 2004-08-19  Last modified: 2006-12-29
    
-
    View all other issues in [base].
    
+
    452.  locale::combine should be permitted to generate a named locale
    
+
    Section: 22.3.1.3 [locale.members] Status: NAD
+ Submitter: Bill Plauger Opened: 2004-01-30  Last modified: 2009-05-01
    
+
    View all other issues in [locale.members].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
-
    The classes std::unary_function and std::binary_function are both
-designed to be inherited from but contain no virtual functions.  This
-makes it too easy for a novice programmer to write code like
-binary_function<int, int, int> *p = new plus<int>; delete p;
    
-
-
    There are two common ways to prevent this source of undefined
-behavior: give the base class a public virtual destructor, or give it
-a protected nonvirtual destructor.  Since unary_function and
-binary_function have no other virtual functions, (note in particular
-the absence of an operator()() ), it would cost too much to give them
-public virtual destructors.  Therefore, they should be given protected
-nonvirtual destructors.
    
-
-
-
    Proposed resolution:
    
-
    Change Paragraph 20.3.1 of the Standard from
    
-
        template <class Arg, class Result>
-    struct unary_function {
-        typedef Arg argument_type;
-        typedef Result result_type;
-    };
-
-    template <class Arg1, class Arg2, class Result>
-    struct binary_function {
-        typedef Arg1 first_argument_type;
-        typedef Arg2 second_argument_type;
-        typedef Result result_type;
-    };
+
    template<class Facet>
+    locale::combine(const locale&) const;
 
    
+
    
+is obliged to create a locale that has no name. This is overspecification
+and overkill. The resulting locale should follow the usual rules -- it
+has a name if the locale argument has a name and Facet is one of the
+standard facets.
+
    
+
+
    [
+ Sydney and post-Sydney (see c++std-lib-13439, c++std-lib-13440,
+ c++std-lib-13443): agreed that it's overkill to say that the locale
+ is obligated to be nameless.  However, we also can't require it to
+ have a name.  At the moment, locale names are based on categories
+ and not on individual facets.  If a locale contains two different
+ facets of different names from the same category, then this would
+ not fit into existing naming schemes.  We need to give
+ implementations more freedom.  Bill will provide wording.
+]
    
 
-
    to
    
-
        template <class Arg, class Result>
-        struct unary_function {
-        typedef Arg argument_type;
-        typedef Result result_type;
-    protected:
-        ~unary_function() {}
-    };
 
-    template <class Arg1, class Arg2, class Result>
-    struct binary_function {
-        typedef Arg1 first_argument_type;
-        typedef Arg2 second_argument_type;
-        typedef Result result_type;
-    protected:
-        ~binary_function() {}
-    };
-
    
 
 
 
    Rationale:
    
-
    The LWG doesn't believe the existing definition causes anybody any
-  concrete harm.
    
+
    After further discussion the LWG decided to close this as NAD.
+  The fundamental problem is that names right now are per-category,
+  not per-facet.  The combine member function works at the
+  wrong level of granularity.
    
 
 
 
 
 
 
    
-
    481. unique's effects on the range [result, last)
    
-
    Section: 25.4.9 [alg.unique] Status: NAD
- Submitter: Andrew Koenig Opened: 2004-08-30  Last modified: 2006-12-27
    
-
    View other active issues in [alg.unique].
    
-
    View all other issues in [alg.unique].
    
+
    454. basic_filebuf::open should accept wchar_t names
    
+
    Section: 27.9.1.4 [filebuf.members] Status: NAD
+ Submitter: Bill Plauger Opened: 2004-01-30  Last modified: 2009-05-01
    
+
    View all other issues in [filebuf.members].
    
 
    View all issues with NAD status.
    
+
    Duplicate of: 105
    
 
    Discussion:
    
-
    
-The standard says that unique(first, last) "eliminates all but the
-first element from every consecutive group of equal elements" in
-[first, last) and returns "the end of the resulting range".  So a
-postcondition is that [first, result) is the same as the old [first,
-last) except that duplicates have been eliminated.
-
    
-
-
    What postconditions are there on the range [result, last)?  One
-  might argue that the standard says nothing about those values, so
-  they can be anything.  One might also argue that the standard
-  doesn't permit those values to be changed, so they must not be.
-  Should the standard say something explicit one way or the other?
    
+
        basic_filebuf *basic_filebuf::open(const char *, ios_base::open_mode);
+
    
 
+
    should be supplemented with the overload:
    
 
+
        basic_filebuf *basic_filebuf::open(const wchar_t *, ios_base::open_mode);
+
    
 
-
    Proposed resolution:
    
 
    
+Depending on the operating system, one of these forms is fundamental and
+the other requires an implementation-defined mapping to determine the
+actual filename.
 
    
 
-
-
    Rationale:
    
-
    We don't want to make many guarantees about what's in [result,
-end). Maybe we aren't being quite explicit enough about not being
-explicit, but it's hard to think that's a major problem.
    
-
-
+
    [Sydney: Yes, we want to allow wchar_t filenames.  Bill will
+  provide wording.]
    
 
 
+
    [
+In Toronto we noted that this is issue 5 from
+N1569.
+]
    
 
-
    
-
    482. Swapping pairs
    
-
    Section: 20.3.3 [pairs], 20.5 [tuple] Status: NAD Editorial
- Submitter: Andrew Koenig Opened: 2004-09-14  Last modified: 2007-05-06
    
-
    View other active issues in [pairs].
    
-
    View all other issues in [pairs].
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
-
    (Based on recent comp.std.c++ discussion)
    
+
    
+How does this interact with the newly-defined character types, and how
+do we avoid interface explosion considering std::string overloads that
+were added? Propose another solution that is different than the
+suggestion proposed by PJP.
+
    
+
    
+Suggestion is to make a member template function for basic_string (for
+char, wchar_t, u16char, u32char instantiations), and then just keep a
+const char* member.
+
    
+
    
+Goal is to do implicit conversion between character string literals to
+appropriate basic_string type. Not quite sure if this is possible.
+
    
+
    
+Implementors are free to add specific overloads for non-char character
+types.
+
    
 
-
    Pair (and tuple) should specialize std::swap to work in terms of
-std::swap on their components.  For example, there's no obvious reason
-why swapping two objects of type pair<vector<int>,
-list<double> > should not take O(1).
    
+
    [
+Martin adds pre-Sophia Antipolis:
+]
    
 
-
    [Lillehammer: We agree it should be swappable.  Howard will
-  provide wording.]
    
 
+
    
+Please see issue 454: problems and solutions.
+
    
 
 
    [
-Post Oxford:  We got swap for pair but accidently
-missed tuple.  tuple::swap is being tracked by 522.
+Sophia Antipolis:
 ]
    
 
 
-
-
-
    Proposed resolution:
    
+
    
 
    
-Wording provided in
-N1856.
+Beman is concerned that making these changes to basic_filebuf is not
+usefully changed unless fstream is also changed; this also only handles
+wchar_t and not other character types.
 
    
-
-
    Rationale:
    
 
    
-Recommend NAD, fixed by 
-N1856.
+The TR2 filesystem library is a more complete solution, but is not available soon.
 
    
+
    
 
+
    [
+Martin adds:  please reference
+N2683 for
+problems and solutions.
+]
    
 
 
 
 
-
    
-
    483. Heterogeneous equality and EqualityComparable
    
-
    Section: 25.3 [alg.nonmodifying], 25.4 [alg.modifying.operations] Status: Dup
- Submitter: Peter Dimov Opened: 2004-09-20  Last modified: 2007-01-15
    
-
    View all issues with Dup status.
    
-
    Duplicate of: 283
    
-
    Discussion:
    
-
    c++std-lib-14262
    
+
    Proposed resolution:
    
 
-
    [lib.alg.find] requires T to be EqualityComparable:
    
+
    Change from:
    
+
    
+
    basic_filebuf<charT,traits>* open(
+    const char* s,
+    ios_base::openmode mode );
+
    
 
-
    template <class InputIterator, class T>
-   InputIterator find(InputIterator first, InputIterator last,
-                      const T& value);
+
    
+Effects: If is_open() != false, returns a null pointer.
+Otherwise, initializes the filebuf as required. It then
+opens a file, if possible, whose name is the NTBS s ("as if"
+by calling std::fopen(s,modstr)).
    
+
    
+
+
    to:
    
+
+
    
+
    basic_filebuf<charT,traits>* open(
+    const char* s,
+    ios_base::openmode mode );
+
+basic_filebuf<charT,traits>* open(
+    const wchar_t* ws,
+    ios_base::openmode mode );
 
    
 
 
    
-However the condition being tested, as specified in the Effects
-clause, is actually *i == value, where i is an InputIterator.
+Effects: If is_open() != false, returns a null pointer.
+Otherwise, initializes the filebuf as required. It then
+opens a file, if possible, whose name is the NTBS s ("as if"
+by calling std::fopen(s,modstr)).
+For the second signature, the NTBS s is determined from the
+WCBS ws in an implementation-defined manner.
 
    
 
 
    
-The two clauses are in agreement only if the type of *i is T, but this
-isn't necessarily the case. *i may have a heterogeneous comparison
-operator that takes a T, or a T may be convertible to the type of *i.
+(NOTE: For a system that "naturally" represents a filename
+as a WCBS, the NTBS s in the first signature may instead
+be mapped to a WCBS; if so, it follows the same mapping
+rules as the first argument to open.)
 
    
+
    
 
-
    Further discussion (c++std-lib-14264): this problem affects a
-  number of algorithsm in clause 25, not just find.  We
-  should try to resolve this problem everywhere it appears.
    
 
 
-
    Proposed resolution:
    
+
    Rationale:
    
+
    
+Slightly controversial, but by a 7-1 straw poll the LWG agreed to move
+this to Ready.  The controversy was because the mapping between wide
+names and files in a filesystem is implementation defined.  The
+counterargument, which most but not all LWG members accepted, is that
+the mapping between narrow files names and files is also
+implemenation defined.
    
 
-
    [lib.alg.find]:
    
-
    
-   Remove [lib.alg.find]/1.
-
    
+
    [Lillehammer: Moved back to "open" status, at Beman's urging.
+(1) Why just basic_filebuf, instead of also basic_fstream (and
+possibly other things too). (2) Why not also constructors that take
+std::basic_string? (3) We might want to wait until we see Beman's
+filesystem library; we might decide that it obviates this.]
    
 
-
    [lib.alg.count]:
    
-
    
-   Remove [lib.alg.count]/1.
-
    
 
-
    [lib.alg.search]:
    
-
    
-   Remove "Type T is EqualityComparable (20.1.1), " from [lib.alg.search]/4.
-
    
+
    [
+post Bellevue:
+]
    
 
-
    [lib.alg.replace]:
    
 
 
    
-   
    
-   Remove [lib.alg.replace]/1.
-   Replace [lb.alg.replace]/2 with:
-   
    
-
-       
    
-       For every iterator i in the range [first, last) for which *i == value
-       or pred(*i) holds perform *i = new_value.
-       
    
-
-   
    
-   Remove the first sentence of /4.
-   Replace the beginning of /5 with:
-   
    
-
-       
    
-       For every iterator i in the range [result, result + (last -
-       first)), assign to *i either...
-       
    
-
-   
    (Note the defect here, current text says assign to i, not *i).
    
+
    
+Move again to Ready.
+
    
+
    
+There is a timing issue here. Since the filesystem library will not be
+in C++0x, this should be brought forward. This solution would remain
+valid in the context of the proposed filesystem.
+
    
+
    
+This issue has been kicking around for a while, and the wchar_t addition
+alone would help many users. Thus, we suggest putting this on the
+reflector list with an invitation for someone to produce proposed
+wording that covers basic_fstream. In the meantime, we suggest that the
+proposed wording be adopted as-is.
+
    
+
    
+If more of the Lillehammer questions come back, they should be
+introduced as separate issues.
+
    
 
    
 
-
    [lib.alg.fill]:
    
+
    [
+San Francisco:
+]
    
 
-
    
-   
    
-   Remove "Type T is Assignable (23.1), " from /1.
-   Replace /2 with:
-   
    
 
-       
    
-       For every iterator i in the range [first, last) or [first, first + n),
-       perform *i = value.
-       
    
+
    
+Some existing implementations provide overload already. Expected
+filesystem "path" object overloads neatly, without surprises; implying
+NAD.
 
    
 
-
    [lib.alg.remove]:
    
-
    
-   Remove /1.
-   Remove the first sentence of /6.
-
    
-
-
-
-
    Rationale:
    
-
    Duplicate of (a subset of) issue 283.
    
 
 
 
@@ -6729,331 +8066,413 @@ operator that takes a T, or a T may be convertible to the type of *i.
 
 
 
    
-
    484. Convertible to T
    
-
    Section: 24.2.2 [input.iterators] Status: NAD Editorial
- Submitter: Chris Jefferson Opened: 2004-09-16  Last modified: 2008-09-26
    
-
    View all other issues in [input.iterators].
    
-
    View all issues with NAD Editorial status.
    
+
    459. Requirement for widening in stage 2 is overspecification
    
+
    Section: 22.4.2.1.2 [facet.num.get.virtuals] Status: NAD
+ Submitter: Martin Sebor Opened: 2004-03-16  Last modified: 2009-07-14
    
+
    View other active issues in [facet.num.get.virtuals].
    
+
    View all other issues in [facet.num.get.virtuals].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
-
    From comp.std.c++:
    
+
    When parsing strings of wide-character digits, the standard
+  requires the library to widen narrow-character "atoms" and compare
+  the widened atoms against the characters that are being parsed.
+  Simply narrowing the wide characters would be far simpler, and
+  probably more efficient.  The two choices are equivalent except in
+  convoluted test cases, and many implementations already ignore the
+  standard and use narrow instead of widen.
    
 
 
    
-I note that given an input iterator a for type T, 
-then *a only has to be "convertable to T", not actually of type T.
+First, I disagree that using narrow() instead of widen() would
+necessarily have unfortunate performance implications. A possible
+implementation of narrow() that allows num_get to be implemented
+in a much simpler and arguably comparably efficient way as calling
+widen() allows, i.e. without making a virtual call to do_narrow every
+time, is as follows:
 
    
 
-
    Firstly, I can't seem to find an exact definition of "convertable to T". 
-While I assume it is the obvious definition (an implicit conversion), I 
-can't find an exact definition. Is there one?
    
-
-
    Slightly more worryingly, there doesn't seem to be any restriction on 
-the this type, other than it is "convertable to T". Consider two input 
-iterators a and b. I would personally assume that most people would 
-expect *a==*b would perform T(*a)==T(*b), however it doesn't seem that 
-the standard requires that, and that whatever type *a is (call it U) 
-could have == defined on it with totally different symantics and still 
-be a valid inputer iterator.
    
-
-
    Is this a correct reading? When using input iterators should I write 
-T(*a) all over the place to be sure that the object i'm using is the 
-class I expect?
    
-
-
    This is especially a nuisance for operations that are defined to be
-  "convertible to bool".  (This is probably allowed so that
-  implementations could return say an int and avoid an unnessary
-  conversion. However all implementations I have seen simply return a
-  bool anyway.  Typical implemtations of STL algorithms just write
-  things like while(a!=b && *a!=0).  But strictly
-  speaking, there are lots of types that are convertible to T but
-  that also overload the appropriate operators so this doesn't behave
-  as expected.
    
-
-
    If we want to make code like this legal (which most people seem to
-  expect), then we'll need to tighten up what we mean by "convertible
-  to T".
    
-
-
    [Lillehammer: The first part is NAD, since "convertible" is
- well-defined in core. The second part is basically about pathological
- overloads. It's a minor problem but a real one. So leave open for
- now, hope we solve it as part of iterator redesign.]
    
+
      inline char ctype<wchar_t>::narrow (wchar_t wc, char dflt) const
+  {
+      const unsigned wi = unsigned (wc);
 
+      if (wi > UCHAR_MAX)
+          return typeid (*this) == typeid (ctype<wchar_t>) ?
+                 dflt : do_narrow (wc, dflt);
 
+      if (narrow_ [wi] < 0) {
+         const char nc = do_narrow (wc, dflt);
+         if (nc == dflt)
+             return dflt;
+         narrow_ [wi] = nc;
+      }
 
+      return char (narrow_ [wi]);
+  }
+
    
 
-
    Proposed resolution:
    
+
    
+Second, I don't think the change proposed in the issue (i.e., to use
+narrow() instead of widen() during Stage 2) would be at all
+drastic. Existing implementations with the exception of libstdc++
+currently already use narrow() so the impact of the change on programs
+would presumably be isolated to just a single implementation. Further,
+since narrow() is not required to translate alternate wide digit
+representations such as those mentioned in issue 303
+to
+their narrow equivalents (i.e., the portable source characters '0'
+through '9'), the change does not necessarily imply that these
+alternate digits would be treated as ordinary digits and accepted as
+part of numbers during parsing. In fact, the requirement in 22.4.1.1.2
+[locale.ctype.virtuals], p13 forbids narrow() to translate an alternate
+digit character, wc, to an ordinary digit in the basic source
+character set unless the expression
+(ctype<charT>::is(ctype_base::digit, wc) == true) holds. This in
+turn is prohibited by the C standard (7.25.2.1.5, 7.25.2.1.5, and
+5.2.1, respectively) for charT of either char or wchar_t.
+
    
+
+
    [Sydney: To a large extent this is a nonproblem. As long as
+you're only trafficking in char and wchar_t we're only dealing with a
+stable character set, so you don't really need either 'widen' or
+'narrow': can just use literals. Finally, it's not even clear whether
+widen-vs-narrow is the right question; arguably we should be using
+codecvt instead.]
    
 
 
-
    Rationale:
    
 
    [
-San Francisco:
+2009-07 Frankfurt
 ]
    
 
 
 
    
-Solved by
-N2758.
+NAD. The standard is clear enough as written.
 
    
 
 
 
-
-
-
-
-
    
-
    486. min/max CopyConstructible requirement is too strict
    
-
    Section: 25.5.7 [alg.min.max] Status: Dup
- Submitter: Dave Abrahams Opened: 2004-10-13  Last modified: 2006-12-30
    
-
    View other active issues in [alg.min.max].
    
-
    View all other issues in [alg.min.max].
    
-
    View all issues with Dup status.
    
-
    Duplicate of: 281
    
-
    Discussion:
    
-
    A straightforward implementation of these algorithms does not need to
-copy T.
    
-
-
 
    Proposed resolution:
    
-
    drop the the words "and CopyConstructible" from paragraphs 1 and 4
    
-
-
-
    Rationale:
    
-
+
    Change stage 2 so that implementations are permitted to use either
+technique to perform the comparison:
    
+
      
+  
    1.  call widen on the atoms and compare (either by using
+      operator== or char_traits<charT>::eq) the input with
+      the widened atoms, or
      2. 
+  
    2.  call narrow on the input and compare the narrow input
+      with the atoms
      3. 
+  
    3.  do (1) or (2) only if charT is not char or wchar_t,
+      respectively; i.e., avoid calling widen or narrow
+      if it the source and destination types are the same
      4. 
+
    
 
 
 
 
 
 
    
-
    487. Allocator::construct is too limiting
    
-
    Section: X [allocator.requirements] Status: NAD
- Submitter: Dhruv Matani Opened: 2004-10-17  Last modified: 2006-12-30
    
-
    View other active issues in [allocator.requirements].
    
-
    View all other issues in [allocator.requirements].
    
+
    462. Destroying objects with static storage duration
    
+
    Section: 3.6.3 [basic.start.term], 18.4 [cstdint] Status: NAD
+ Submitter: Bill Plauger Opened: 2004-03-23  Last modified: 2008-02-25
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-The standard's version of allocator::construct(pointer,
-const_reference) severely limits what you can construct using this
-function.  Say you can construct a socket from a file descriptor. Now,
-using this syntax, I first have to manually construct a socket from
-the fd, and then pass the constructed socket to the construct()
-function so it will just to an uninitialized copy of the socket I
-manually constructed. Now it may not always be possible to copy
-construct a socket eh! So, I feel that the changes should go in the
-allocator::construct(), making it:
+3.6.3 Termination spells out in detail the interleaving of static
+destructor calls and calls to functions registered with atexit. To
+match this behavior requires intimate cooperation between the code
+that calls destructors and the exit/atexit machinery. The former
+is tied tightly to the compiler; the latter is a primitive mechanism
+inherited from C that traditionally has nothing to do with static
+construction and destruction. The benefits of intermixing destructor
+calls with atexit handler calls is questionable at best, and very
+difficult to get right, particularly when mixing third-party C++
+libraries with different third-party C++ compilers and C libraries
+supplied by still other parties.
 
    
-
        template<typename T>
-    struct allocator{
-      template<typename T1>
-      void construct(pointer T1 const& rt1);
-    };
-
    
 
 
    
-Now, the ctor of the class T which matches the one that takes a T1 can
-be called! Doesn't that sound great?
+I believe the right thing to do is defer all static destruction
+until after all atexit handlers are called. This is a change in
+behavior, but one that is likely visible only to perverse test
+suites. At the very least, we should permit deferred destruction
+even if we don't require it.
 
    
 
+
    [If this is to be changed, it should probably be changed by CWG.
+  At this point, however, the LWG is leaning toward NAD.  Implementing
+  what the standard says is hard work, but it's not impossible and
+  most vendors went through that pain years ago.  Changing this
+  behavior would be a user-visible change, and would break at least
+  one real application.]
    
 
-
    Proposed resolution:
    
 
+
    [
+Batavia:  Send to core with our recommendation that we should permit deferred
+destruction but not require it.
+]
    
 
-
    Rationale:
    
-
    NAD. STL uses copying all the time, and making it possible for
-  allocators to construct noncopyable objects is useless in the
-  absence of corresponding container changes. We might consider this
-  as part of a larger redesign of STL.
    
 
+
    [
+Howard:  The course of action recommended in Batavia would undo LWG
+issue 3 and break current code implementing the "phoenix
+singleton". Search the net for "phoenix singleton atexit" to get a feel
+for the size of the adverse impact this change would have.  Below is
+sample code which implements the phoenix singleton and would break if
+atexit is changed in this way:
+]
    
 
 
+
    #include <cstdlib>
+#include <iostream>
+#include <type_traits>
+#include <new>
 
+class A
+{
+    bool alive_;
+    A(const A&);
+    A& operator=(const A&);
+public:
+    A() : alive_(true) {std::cout << "A()\n";}
+    ~A() {alive_ = false; std::cout << "~A()\n";}
+    void use()
+    {
+        if (alive_)
+            std::cout << "A is alive\n";
+        else
+            std::cout << "A is dead\n";
+    }
+};
 
-
    
-
    489. std::remove / std::remove_if wrongly specified
    
-
    Section: 25.4.8 [alg.remove] Status: NAD
- Submitter: Thomas Mang Opened: 2004-12-12  Last modified: 2006-12-27
    
-
    View all other issues in [alg.remove].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
-
    In Section 25.2.7 [lib.alg.remove], paragraphs 1 to 5 describe the
-behavior of the mutating sequence operations std::remove and
-std::remove_if. However, the wording does not reflect the intended
-behavior [Note: See definition of intended behavior below] of these
-algorithms, as it is known to the C++ community [1].
-
    
+void deallocate_resource();
 
+// This is the phoenix singleton pattern
+A& get_resource(bool create = true)
+{
+    static std::aligned_storage<sizeof(A), std::alignment_of<A>::value>::type buf;
+    static A* a;
+    if (create)
+    {
+        if (a != (A*)&buf)
+        {
+            a = ::new (&buf) A;
+            std::atexit(deallocate_resource);
+        }
+    }
+    else
+    {
+        a->~A();
+        a = (A*)&buf + 1;
+    }
+    return *a;
+}
 
+void deallocate_resource()
+{
+    get_resource(false);
+}
 
-
    1) Analysis of current wording:
    
+void use_A(const char* message)
+{
+    A& a = get_resource();
+    std::cout << "Using A " << message << "\n";
+    a.use();
+}
 
+struct B
+{
+    ~B() {use_A("from ~B()");}
+};
 
-
    25.2.7 [lib.alg.remove], paragraph 2:
    
+B b;
 
-
    Current wording says:
-"Effects: Eliminates all the elements referred to by iterator i in the
-range [first, last) for which the following corresponding conditions
-hold: *i == value, pred(*i) != false."
    
+int main()
+{
+    use_A("from main()");
+}
+
    
 
 
    
-This sentences expresses specifically that all elements denoted by the
-(original) range [first, last) for which the corresponding condition
-hold will be eliminated. Since there is no formal definition of the term
-"eliminate" provided, the meaning of "eliminate" in everyday language
-implies that as postcondition, no element in the range denoted by
-[first, last) will hold the corresponding condition on reiteration over
-the range [first, last).
+The correct output is:
 
    
 
-
    
-However, this is neither the intent [Note: See definition of intended
-behavior below] nor a general possible approach. It can be easily proven
-that if all elements of the original range[first, last) will hold the
-condition, it is not possible to substitute them by an element for which
-the condition will not hold.
-
    
+
    A()
+Using A from main()
+A is alive
+~A()
+A()
+Using A from ~B()
+A is alive
+~A()
+
    
+
+
    [
+Bellevue: Confirmed no interaction with quick_exit.
+Strong feeling against mandating the change. Leaning towards NAD rather than permitting the change,
+as this would make common implementations of pheonix-singleton pattern implementation defined, as noted by Howard.
+Bill agrees issue is no longer serious, and accepts NAD.
+]
    
 
 
-
    25.2.7 [lib.alg.remove], paragraph 3:
    
 
-
    
-Current wording says:
-"Returns: The end of the resulting range."
-
    
 
+
    Proposed resolution:
    
 
    
-The resulting range is not specified. In combination with 25.2.7
-[lib.alg.remove], paragraph 2, the only reasonable interpretation of
-this so-called resulting range is the range [first,last) - thus
-returning always the ForwardIterator 'last' parameter.
 
    
 
 
+
+
+
+
    
+
    466. basic_string ctor should prevent null pointer error
    
+
    Section: 21.4.1 [string.require] Status: NAD
+ Submitter: Daniel Frey Opened: 2004-06-10  Last modified: 2009-07-14
    
+
    View all other issues in [string.require].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
    
-25.2.7 [lib.alg.remove], paragraph 4:
+Today, my colleagues and me wasted a lot of time. After some time, I
+found the problem. It could be reduced to the following short example:
 
    
 
+
      #include <string>
+  int main() { std::string( 0 ); }
+
    
+
+
    The problem is that the tested compilers (GCC 2.95.2, GCC 3.3.1 and
+Comeau online) compile the above without errors or warnings! The
+programs (at least for the GCC) resulted in a SEGV.
    
+
+
    I know that the standard explicitly states that the ctor of string
+requires a char* which is not zero. STLs could easily detect the above
+case with a private ctor for basic_string which takes a single 'int'
+argument. This would catch the above code at compile time and would not
+ambiguate any other legal ctors.
    
+
+
    [Redmond: No great enthusiasm for doing this.  If we do,
+  however, we want to do it for all places that take charT*
+  pointers, not just the single-argument constructor.  The other
+  question is whether we want to catch this at compile time (in which
+  case we catch the error of a literal 0, but not an expression whose
+  value is a null pointer), at run time, or both.
+  Recommend NAD.  Relegate this functionality to debugging implementations.]
    
+
+
+
    [
+Post Summit: Alisdair requests this be re-opened as several new language facilities are
+designed to solve exactly this kind of problem.
+]
    
+
+
+
    [
+Batavia (2009-05):
+]
    
+
+
    
+We are unable to achieve consensus on an approach to a resolution.
+There is some sentiment for treating this as a QOI matter.
+It is also possible
+that when string is brought into the concepts world,
+this issue might be addressed in that context.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
 
    
-Current wording says:
-"Notes: Stable: the relative order of the elements that are not removed
-is the same as their relative order in the original range"
+We considered three options:
 
    
 
+
      
+
    • The proposed resolution.
      • 
+
    • NAD
      • 
+
    • Interpret a null pointer as the empty string.
      • 
+
    
+
 
    
-This sentences makes use of the term "removed", which is neither
-specified, nor used in a previous paragraph (which uses the term
-"eliminate"), nor unamgiuously separated from the name of the algorithm.
+The consensus was NAD.
 
    
+
    
 
 
-
    2) Description of intended behavior:
    
 
+
    Proposed resolution:
    
 
    
-For the rest of this Defect Report, it is assumed that the intended
-behavior was that all elements of the range [first, last) which do not
-hold the condition *i == value (std::remove) or  pred(*i) != false
-(std::remove_if)], call them s-elements [Note: s...stay], will be placed
-into a contiguous subrange of [first, last), denoted by the iterators
-[first, return value). The number of elements in the resulting range
-[first, return value) shall be equal to the number of s-elements in the
-original range [first, last). The relative order of the elements in the
-resulting subrange[first, return value) shall be the same as the
-relative order of the corresponding elements in the original range. It
-is undefined whether any elements in the resulting subrange [return
-value, last) will hold the corresponding condition, or not.
+Add to the synopsis in 21.4 [basic.string]
 
    
 
-
    
-All implementations known to the author of this Defect Report comply
-with this intent. Since the intent  of the behavior (contrary to the
-current wording) is also described in various utility references serving
-the C++ community [1], it is not expected that fixing the paragraphs
-will influence current code - unless the code relies on the behavior as
-it is described by current wording and the implementation indeed
-reflects the current wording, and not the intent.
-
    
+
    basic_string( nullptr_t ) = delete;
+
    
 
 
 
-
    3) Proposed fixes:
    
 
 
-
    Change 25.2.7 [lib.alg.remove], paragraph 2 to:
    
+
    
+
    470. accessing containers from their elements' special functions
    
+
    Section: 23 [containers] Status: NAD
+ Submitter: Martin Sebor Opened: 2004-06-28  Last modified: 2007-04-18
    
+
    View other active issues in [containers].
    
+
    View all other issues in [containers].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
 
    
-"Effect: Places all the elements referred to by iterator i in the range
-[first, last) for which the following corresponding conditions hold :
-!(*i == value), pred(*i) == false into the subrange [first, k) of the
-original range, where k shall denote a value of type ForwardIterator. It
-is undefined whether any elements in the resulting subrange [k, last)
-will hold the corresponding condition, or not."
+The standard doesn't prohibit the destructors (or any other special
+functions) of containers' elements invoked from a member function
+of the container from "recursively" calling the same (or any other)
+member function on the same container object, potentially while the
+container is in an intermediate state, or even changing the state
+of the container object while it is being modified. This may result
+in some surprising (i.e., undefined) behavior.
 
    
 
-
    Comments to the new wording:
    
+
    Read email thread starting with c++std-lib-13637 for more.
    
 
-
    
-a) "Places" has no special meaning, and the everyday language meaning
-should fit.
-b) The corresponding conditions were negated compared to the current
-wording, becaue the new wording requires it.
-c) The wording "of the original range" might be redundant, since any
-subrange starting at 'first' and containing no more elements than the
-original range is implicitly a subrange of the original range [first,
-last).
-d) The iterator k was introduced instead of "return value" in order to
-avoid a cyclic dependency on 25.2.7/3. The wording ", where k shall
-denote a value of type ForwardIterator" might be redundant, because it
-follows implicitly by 25.2.7/3.
-e) "Places" does, in the author's opinion, explicitly forbid duplicating
-any element holding the corresponding condition in the original range
-[first, last) within the resulting range [first, k). If there is doubt
-this term might be not unambiguous regarding this, it is suggested that
-k is specified more closely by the following wording: "k shall denote a
-value of type ForwardIterator [Note: see d)] so that k - first is equal
-to the number of elements in the original range [first, last) for which
-the corresponding condition did hold". This could also be expressed as a
-separate paragraph "Postcondition:"
-f) The senctence "It is undefined whether any elements in the resulting
-subrange [k, last) will hold the corresponding condition, or not." was
-added consciously so the term "Places" does not imply if the original
-range [first, last) contains n elements holding the corresponding
-condition, the identical range[first, last) will also contain exactly n
-elements holding the corresponding condition after application of the
-algorithm.
-
    
 
-
    
-Change 25.2.7 [lib.alg.remove], paragraph 3 to:
 
-"Returns: The iterator k."
-
    
+
    Proposed resolution:
    
 
-
    
-Change 25.2.7 [lib.alg.remove], paragraph 4 to:
+
    Add to Container Requirements the following new paragraph:
    
 
-"Notes: Stable: the relative order of the elements that are placed into
-the subrange [first, return value) shall be the same as their relative
-order was in the original range [first, last) prior to application of
-the algorithm."
-
    
+
        Unless otherwise specified, the behavior of a program that
+    invokes a container member function f from a member function
+    g of the container's value_type on a container object c that
+    called g from its mutating member function h, is undefined.
+    I.e., if v is an element of c, directly or indirectly calling
+    c.h() from v.g() called from c.f(), is undefined.
+
    
+
+
    [Redmond: This is a real issue, but it's probably a clause 17
+  issue, not clause 23.  We get the same issue, for example, if we
+  try to destroy a stream from one of the stream's callback functions.]
    
+
+  
 
-
    
-Comments to the new wording:
-
    
 
+
    Rationale:
    
 
    
-a) the wording "was ...  prior to application of the algorithm" is used
-to explicitly distinguish the original range not only by means of
-iterators, but also by a 'chronological' factor from the resulting range
-[first, return value). It might be redundant.
+Recommend NAD.  We agree this is an issue, but not a defect.
+We believe that there is no wording we can put in the standard
+that will cover all cases without introducing unfortunate
+corner cases.
 
    
 
+
+
+
+
+
    
+
    472. Missing "Returns" clause in std::equal_range
    
+
    Section: 25.5.3.3 [equal.range] Status: Dup
+ Submitter: Prateek R Karandikar Opened: 2004-06-30  Last modified: 2006-12-30
    
+
    View all other issues in [equal.range].
    
+
    View all issues with Dup status.
    
+
    Duplicate of: 270
    
+
    Discussion:
    
 
    
-[1]:
-The wording of these references is not always unambiguous, and provided
-examples partially contradict verbal description of the algorithms,
-because the verbal description resembles the problematic wording of
-ISO/IEC 14882:2003.
+There is no "Returns:" clause for std::equal_range, which returns non-void.
 
    
 
 
@@ -7061,1337 +8480,1335 @@ ISO/IEC 14882:2003.
 
 
 
    Rationale:
    
-
    The LWG believes that the standard is sufficiently clear, and that
-  there is no evidence of any real-world confusion about this point.
    
+
    Fixed as part of issue 270.
    
+
 
 
 
 
 
 
    
-
    490. std::unique wrongly specified
    
-
    Section: 25.4.9 [alg.unique] Status: NAD
- Submitter: Thomas Mang Opened: 2004-12-12  Last modified: 2006-12-27
    
-
    View other active issues in [alg.unique].
    
-
    View all other issues in [alg.unique].
    
+
    476. Forward Iterator implied mutability
    
+
    Section: 24.2.4 [forward.iterators] Status: NAD
+ Submitter: Dave Abrahams Opened: 2004-07-09  Last modified: 2007-01-15
    
+
    View all other issues in [forward.iterators].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
-
    In Section 25.2.8 [lib.alg.unique], paragraphs 1 to 3 describe the
-behavior of the mutating sequence operation std::unique. However, the
-wording does not reflect the intended behavior [Note: See definition of
-intended behavior below] of these algorithms, as it is known to the C++
-community [1].
    
 
+
    24.1/3 says:
    
+
    
+  Forward iterators satisfy all the requirements of the input and
+  output iterators and can be used whenever either kind is specified
+
    
 
+
    
+The problem is that satisfying the requirements of output iterator
+means that you can always assign *something* into the result of
+dereferencing it.  That makes almost all non-mutable forward
+iterators non-conforming.  I think we need to sever the refinement
+relationship between forward iterator and output iterator.
+
    
 
-
    1) Analysis of current wording:
    
+
    Related issue: 200.  But this is not a dup.
    
 
 
-
    25.2.8 [lib.alg.unique], paragraph 1:
    
 
-
    
-Current wording says:
-"Effects: Eliminates all but the first element from every consecutive
-group of equal elements referred to by the iterator i in the range
-[first, last) for which the following corresponding conditions hold: *i
-== *(i - 1) or pred(*i, *(i -1)) != false"
-
    
+
    Proposed resolution:
    
 
-
    
-This sentences expresses specifically that all elements denoted by the
-(original) range [first, last) which are not but the first element from
-a consecutive group of equal elements (where equality is defined as *i
-== *(i - 1) or pred(*i, *(i - 1)) ! = false) [Note: See DR 202], call
-them r-elements [Note: r...remove], will be eliminated. Since there is
-no formal definition of the term "eliminate" provided, it is undefined
-how this "elimination" takes place. But the meaning of "eliminate" in
-everyday language seems to disallow explicitly that after application of
-the algorithm, any r-element will remain at any position of the range
-[first, last) [2].
-
    
 
-
    
-Another defect in the current wording concerns the iterators used to
-compare two elements for equality: The current wording contains the
-expression "(i - 1)", which is not covered by 25/9 [Note: See DR
-submitted by Thomas Mang regarding invalid iterator arithmetic
-expressions].
-
    
+
    Rationale:
    
+
    Yes, 24.1/3 does say that. But it's introductory material. The
+precise specification is in 24.1.3, and the requrements table there is
+right.  We don't need to fine-tune introductory wording.  (Especially
+since this wording is likely to be changed as part of the iterator
+overhaul.)
     
 
 
-
    
-25.2.8 [lib.alg.unique], paragraph 2:
-
    
-
    Current wording says:
-"Returns: The end of the resulting range."
    
 
-
    
-The resulting range is not specified. In combination with 25.2.8
-[lib.alg.unique], paragraph 1, one reasonable interpretation (in the
-author's opinion even the only possible interpretation) of this
-so-called resulting range is the range [first, last) - thus returning
-always the ForwardIterator 'last' parameter.
-
    
 
-
    2) Description of intended behavior:
    
 
+
    
+
    477. Operator-> for const forward iterators
    
+
    Section: 24.2.4 [forward.iterators] Status: Dup
+ Submitter: Dave Abrahams Opened: 2004-07-11  Last modified: 2007-01-15
    
+
    View all other issues in [forward.iterators].
    
+
    View all issues with Dup status.
    
+
    Duplicate of: 478
    
+
    Discussion:
    
 
    
-For the rest of this Defect Report, it is assumed that the intended
-behavior was that all elements denoted by the original range [first,
-last) which are the first element from a consecutive group of elements
-for which the corresponding conditions: *(i-1) == *i (for the version of
-unique without a predicate argument) or pred(*(i-1), *i) ! = false (for
-the version of unique with a predicate argument) [Note: If such a group
-of elements consists of only a single element, this is also considered
-the first element] [Note: See resolutions of DR 202], call them
-s-elements [Note: s...stay], will be placed into a contiguous subrange
-of [first, last), denoted by the iterators [first, return value). The
-number of elements in the resulting range [first, return value) shall be
-equal to the number of s-elements in the original range [first, last).
-Invalid iterator arithmetic expressions are expected to be resolved as
-proposed in DR submitted by Thomas Mang regarding invalid iterator
-arithmetic expressions. It is also assumed by the author that the
-relative order of the elements in the resulting subrange [first, return
-value) shall be the same as the relative order of the corresponding
-elements (the s-elements) in the original range [Note: If this was not
-intended behavior, the additional proposed paragraph about stable order
-will certainly become obsolete].
-Furthermore, the resolutions of DR 202 are partially considered.
+The Forward Iterator requirements table contains the following:
 
    
+
     expression  return type         operational  precondition
+                                  semantics
+  ==========  ==================  ===========  ==========================
+  a->m        U& if X is mutable, (*a).m       pre: (*a).m is well-defined.
+              otherwise const U&
+
+  r->m        U&                  (*r).m       pre: (*r).m is well-defined.
+
    
 
 
    
-All implementations known to the author of this Defect Report comply
-with this intent [Note: Except possible effects of DR 202]. Since this
-intent of the behavior (contrary to the current wording) is also
-described in various utility references serving the C++ community [1],
-it is not expected that fixing the paragraphs will influence current
-code [Note: Except possible effects of DR 202] - unless the code relies
-on the behavior as it is described by current wording and the
-implementation indeed reflects the current wording, and not the intent.
+The first line is exactly right.  The second line is wrong.  Basically
+it implies that the const-ness of the iterator affects the const-ness
+of referenced members.  But Paragraph 11 of [lib.iterator.requirements] says:
 
    
 
+
    
+   In the following sections, a and b denote values of type const X, n
+   denotes a value of the difference type Distance, u, tmp, and m
+   denote identifiers, r denotes a value of X&, t denotes a value of
+   value type T, o denotes a value of some type that is writable to
+   the output iterator.
+
    
 
+
    AFAICT if we need the second line at all, it should read the same
+as the first line.
    
 
-
    3) Proposed fixes:
    
-
-
    
-Change 25.2.8 [lib.alg.unique], paragraph 1 to:
-
    
+
    Related issue: 478
    
 
-
    
-"Effect: Places the first element from every consecutive group of
-elements, referred to by the iterator i in the range [first, last), for
-which the following conditions hold: *(i-1) == *i (for the version of
-unique without a predicate argument) or pred(*(i -1), *i) != false (for
-the version of unique with a predicate argument), into the subrange
-[first, k) of the original range, where k shall denote a value of type
-ForwardIterator."
-
    
 
-
    Comments to the new wording:
    
+
    Proposed resolution:
    
 
-
    
-a) The new wording was influenced by the resolutions of DR 202. If DR
-202 is resolved in another way, the proposed wording need also
-additional review.
-b) "Places" has no special meaning, and the everyday language meaning
-should fit.
-c) The expression "(i - 1)" was left, but is expected that DR submitted
-by Thomas Mang regarding invalid iterator arithmetic expressions will
-take this into account.
-d) The wording "(for the version of unique without a predicate
-argument)" and "(for the version of unique with a predicate argument)"
-was added consciously for clarity and is in resemblence with current
-23.2.2.4 [lib.list.ops], paragraph 19. It might be considered redundant.
-e) The wording "of the original range" might be redundant, since any
-subrange starting at first and containing no more elements than the
-original range is implicitly a subrange of the original range [first,
-last).
-f) The iterator k was introduced instead of "return value" in order to
-avoid a cyclic dependency on 25.2.8 [lib.alg.unique], paragraph 2. The
-wording ", where k shall denote a value of type ForwardIterator" might
-be redundant, because it follows implicitly by 25.2.8 [lib.alg.unique],
-paragraph 2.
-g) "Places" does, in the author's opinion, explicitly forbid duplicating
-any s-element in the original range [first, last) within the resulting
-range [first, k). If there is doubt this term might be not unambiguous
-regarding this, it is suggested that k is specified more closely by the
-following wording: "k shall denote a value of type ForwardIterator
-[Note: See f)] so that k - first is equal to the number of elements in
-the original range [first, last) being the first element from every
-consecutive group of elements for which the corresponding condition did
-hold". This could also be expressed as a separate paragraph
-"Postcondition:".
-h) If it is considered that the wording is unclear whether it declares
-the element of a group which consists of only a single element
-implicitly to be the first element of this group [Note: Such an
-interpretation could eventually arise especially in case last - first ==
-1] , the following additional sentence is proposed: "If such a group of
-elements consists of only a single element, this element is also
-considered the first element."
-
    
 
-
    
-Change 25.2.8 [lib.alg.unique], paragraph 2 to:
-"Returns: The iterator k."
+
    Rationale:
    
+
    The LWG agrees that this is a real problem.  Marked as a DUP
+  because the LWG chose to adopt the solution proposed in
+  478.
 
    
 
-
    
-Add a separate paragraph "Notes:" as 25.2.8 [lib.alg.unique], paragraph
-2a or 3a, or a separate paragraph "Postcondition:" before 25.2.8
-[lib.alg.unique], paragraph 2 (wording inside {} shall be eliminated if
-the preceding expressions are used, or the preceding expressions shall
-be eliminated if wording inside {} is used):
-
    
 
-
    
-"Notes:{Postcondition:} Stable: the relative order of the elements that
-are placed into the subrange [first, return value {k}) shall be the same
-as their relative order was in the original range [first, last) prior to
-application of the algorithm."
-
    
 
-
    Comments to the new wording:
    
 
-
    
-a) It is assumed by the author that the algorithm was intended to be
-stable.
-In case this was not the intent, this paragraph becomes certainly
-obsolete.
-b) The wording "was ...  prior to application of the algorithm" is used
-to explicitly distinguish the original range not only by means of
-iterators, but also by a 'chronological' factor from the resulting range
-[first, return value). It might be redundant.
-
    
 
-
    
-25.2.8 [lib.alg.unique], paragraph 3:
-
    
-
    See DR 239.
    
+
    
+
    479. Container requirements and placement new
    
+
    Section: 23.2 [container.requirements] Status: Dup
+ Submitter: Herb Sutter Opened: 2004-08-01  Last modified: 2007-04-18
    
+
    View other active issues in [container.requirements].
    
+
    View all other issues in [container.requirements].
    
+
    View all issues with Dup status.
    
+
    Duplicate of: 580
    
+
    Discussion:
    
+
    Nothing in the standard appears to make this program ill-formed:
    
 
-
    
-4) References to other DRs:
-
    
+
      struct C {
+    void* operator new( size_t s ) { return ::operator new( s ); }
+    // NOTE: this hides in-place and nothrow new
+  };
 
-
    
-See DR 202, but which does not address any of the problems described in
-this Defect Report [Note: This DR is supposed to complement DR 202].
-See DR 239.
-See DR submitted by Thomas Mang regarding invalid iterator arithmetic
-expressions.
-
    
+  int main() {
+    vector<C> v;
+    v.push_back( C() );
+  }
+
    
 
-
    
-[1]:
-The wording of these references is not always unambiguous, and provided
-examples partially contradict verbal description of the algorithms,
-because the verbal description resembles the problematic wording of
-ISO/IEC 14882:2003.
-
    
+
    Is that intentional?  We should clarify whether or not we intended
+  to require containers to support types that define their own special
+  versions of operator new.
    
 
-
    
-[2]:
-Illustration of conforming implementations according to current wording:
-
    
+
    [
+Lillehammer: A container will definitely never use this overridden
+operator new, but whether it will fail to compile is unclear from the
+standard.  Are containers supposed to use qualified or unqualified
+placement new?  20.4.1.1 is somewhat relevant, but the standard
+doesn't make it completely clear whether containers have to use
+Allocator::construct(). If containers don't use it, the details of how
+containers use placement new are unspecified. That is the real bug,
+but it needs to be fixed as part of the allocator overhaul.  Weak
+support that the eventual solution should make this code well formed.
+]
    
 
-
    
-One way the author of this DR considers how this "elimination" could be
-achieved by a conforming implementation according to current wording is
-by substituting each r-element by _any_ s-element [Note: s...stay; any
-non-r-element], since all r-elements are "eliminated".
-
    
 
-
    
-In case of a sequence consisting of elements being all 'equal' [Note:
-See DR 202], substituting each r-element by the single s-element is the
-only possible solution according to current wording.
-
    
 
 
 
    Proposed resolution:
    
 
 
-
    Rationale:
    
-
    The LWG believes the standard is sufficiently clear. No
-implementers get it wrong, and changing it wouldn't cause any code to
-change, so there is no real-world harm here.
    
 
 
 
 
 
 
    
-
    491. std::list<>::unique incorrectly specified
    
-
    Section: 23.3.4.4 [list.ops] Status: NAD
- Submitter: Thomas Mang Opened: 2004-12-12  Last modified: 2007-02-19
    
-
    View all other issues in [list.ops].
    
+
    480. unary_function and binary_function should have protected nonvirtual destructors
    
+
    Section: 20.7.3 [base] Status: NAD
+ Submitter: Joe Gottman Opened: 2004-08-19  Last modified: 2006-12-29
    
+
    View all other issues in [base].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
-
    In Section 23.3.4.4 [list.ops], paragraphs 19 to 21 describe the
-behavior of the std::list<T, Allocator>::unique operation. However, the
-current wording is defective for various reasons.
    
+
    The classes std::unary_function and std::binary_function are both
+designed to be inherited from but contain no virtual functions.  This
+makes it too easy for a novice programmer to write code like
+binary_function<int, int, int> *p = new plus<int>; delete p;
    
 
+
    There are two common ways to prevent this source of undefined
+behavior: give the base class a public virtual destructor, or give it
+a protected nonvirtual destructor.  Since unary_function and
+binary_function have no other virtual functions, (note in particular
+the absence of an operator()() ), it would cost too much to give them
+public virtual destructors.  Therefore, they should be given protected
+nonvirtual destructors.
    
 
 
-
    
-1) Analysis of current wording:
-
    
+
    Proposed resolution:
    
+
    Change Paragraph 20.3.1 of the Standard from
    
+
        template <class Arg, class Result>
+    struct unary_function {
+        typedef Arg argument_type;
+        typedef Result result_type;
+    };
 
-
    23.3.4.4 [list.ops], paragraph 19:
    
+    template <class Arg1, class Arg2, class Result>
+    struct binary_function {
+        typedef Arg1 first_argument_type;
+        typedef Arg2 second_argument_type;
+        typedef Result result_type;
+    };
+
    
 
-
    
-Current wording says:
-"Effects:  Eliminates all but the first element from every consecutive
-group of equal elements referred to by the iterator i in the range
-[first + 1, last) for which *i == *(i - 1) (for the version of unique
-with no argument) or pred(*i, *(i -1)) (for the version of unique with a
-predicate argument) holds."
    
+
    to
    
+
        template <class Arg, class Result>
+        struct unary_function {
+        typedef Arg argument_type;
+        typedef Result result_type;
+    protected:
+        ~unary_function() {}
+    };
 
-
    
-This sentences makes use of the undefined term "Eliminates". Although it
-is, to a certain degree, reasonable to consider the term "eliminate"
-synonymous with "erase", using "Erase" in the first place, as the
-wording of 23.3.4.4 [list.ops], paragraph 15 does, would be clearer.
    
+    template <class Arg1, class Arg2, class Result>
+    struct binary_function {
+        typedef Arg1 first_argument_type;
+        typedef Arg2 second_argument_type;
+        typedef Result result_type;
+    protected:
+        ~binary_function() {}
+    };
+
    
 
-
    
-The range of the elements referred to by iterator i is "[first + 1,
-last)". However, neither "first" nor "last" is defined.
    
 
-
    
-The sentence makes three times use of iterator arithmetic expressions (
-"first + 1", "*i == *(i - 1)", "pred(*i, *(i -1))" ) which is not
-defined for bidirectional iterator [see DR submitted by Thomas Mang
-regarding invalid iterator arithmetic expressions].
    
+
    Rationale:
    
+
    The LWG doesn't believe the existing definition causes anybody any
+  concrete harm.
    
 
-
    
-The same problems as pointed out in DR 202 (equivalence relation / order
-of arguments for pred()) apply to this paragraph.
    
 
-
    
-23.3.4.4 [list.ops], paragraph 20:
-
    
 
-
    
-Current wording says:
-"Throws: Nothing unless an exception in thrown by *i == *(i-1) or
-pred(*i, *(i - 1))"
    
 
+
+
    
+
    481. unique's effects on the range [result, last)
    
+
    Section: 25.4.9 [alg.unique] Status: NAD
+ Submitter: Andrew Koenig Opened: 2004-08-30  Last modified: 2006-12-27
    
+
    View all other issues in [alg.unique].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
    
-The sentence makes two times use of invalid iterator arithmetic
-expressions ( "*i == *(i - 1)", "pred(*i, *(i -1))" ).
-
    
-
    
-[Note: Minor typos: "in" / missing dot at end of sentence.]
+The standard says that unique(first, last) "eliminates all but the
+first element from every consecutive group of equal elements" in
+[first, last) and returns "the end of the resulting range".  So a
+postcondition is that [first, result) is the same as the old [first,
+last) except that duplicates have been eliminated.
 
    
 
-
    
-23.3.4.4 [list.ops], paragraph 21:
    
+
    What postconditions are there on the range [result, last)?  One
+  might argue that the standard says nothing about those values, so
+  they can be anything.  One might also argue that the standard
+  doesn't permit those values to be changed, so they must not be.
+  Should the standard say something explicit one way or the other?
    
 
-
    
-Current wording says:
-"Complexity: If the range (last - first) is not empty, exactly (last -
-first) - 1 applications of the corresponding predicate, otherwise no
-application of the predicate.
    
 
-
    
-See DR 315 regarding "(last - first)" not yielding a range.
    
 
+
    Proposed resolution:
    
 
    
-Invalid iterator arithmetic expression "(last - first) - 1" left .
    
-
-
-
    2) Description of intended behavior:
    
+
    
 
-
    
-For the rest of this Defect Report, it is assumed that "eliminate" is
-supposed to be synonymous to "erase", that "first" is equivalent to an
-iterator obtained by a call to begin(), "last" is equivalent to an
-iterator obtained by a call to end(), and that all invalid iterator
-arithmetic expressions are resolved as described in DR submitted by
-Thomas Mang regarding invalid iterator arithmetic expressions.
    
 
-
    
-Furthermore, the resolutions of DR 202 are considered regarding
-equivalence relation and order of arguments for a call to pred.
    
+
    Rationale:
    
+
    We don't want to make many guarantees about what's in [result,
+end). Maybe we aren't being quite explicit enough about not being
+explicit, but it's hard to think that's a major problem.
    
 
-
    
-All implementations known to the author of this Defect Report comply
-with these assumptions, apart from the impact of the alternative
-resolution of DR 202. Except for the changes implied by the resolutions
-of DR 202, no impact on current code is expected.
    
 
-
    
-3) Proposed fixes:
    
 
-
    
-Change 23.3.4.4 [list.ops], paragraph 19 to:
    
 
-
    
-"Effect: Erases all but the first element from every consecutive group
-of elements, referred to by the iterator i in the range [begin(),
-end()), for which the following conditions hold: *(i-1) == *i (for the
-version of unique with no argument) or pred(*(i-1), *i) != false (for
-the version of unique with a predicate argument)."
    
 
-
    
-Comments to the new wording:
    
+
    
+
    482. Swapping pairs
    
+
    Section: 20.3.3 [pairs], 20.5 [tuple] Status: NAD Editorial
+ Submitter: Andrew Koenig Opened: 2004-09-14  Last modified: 2007-05-06
    
+
    View other active issues in [pairs].
    
+
    View all other issues in [pairs].
    
+
    View all issues with NAD Editorial status.
    
+
    Discussion:
    
+
    (Based on recent comp.std.c++ discussion)
    
 
-
    
-a) The new wording was influenced by DR 202 and the resolutions
-presented there. If DR 202 is resolved in another way, the proposed
-wording need also additional review.
-b) "Erases" refers in the author's opinion unambiguously to the member
-function "erase". In case there is doubt this might not be unamgibuous,
-a direct reference to the member function "erase" is suggested [Note:
-This would also imply a change of 23.3.4.4 [list.ops], paragraph
-15.].
-c) The expression "(i - 1)" was left, but is expected that DR submitted
-by Thomas Mang regarding invalid iterator arithmetic expressions will
-take this into account.
-d) The wording "(for the version of unique with no argument)" and "(for
-the version of unique with a predicate argument)" was kept consciously
-for clarity.
-e) "begin()" substitutes "first", and "end()" substitutes "last". The
-range need adjustment from "[first + 1, last)" to "[begin(), end())" to
-ensure a valid range in case of an empty list.
-f) If it is considered that the wording is unclear whether it declares
-the element of a group which consists of only a single element
-implicitly to be the first element of this group [Note: Such an
-interpretation could eventually arise especially in case size() == 1] ,
-the following additional sentence is proposed: "If such a group of
-elements consists of only a single element, this element is also
-considered the first element."
    
+
    Pair (and tuple) should specialize std::swap to work in terms of
+std::swap on their components.  For example, there's no obvious reason
+why swapping two objects of type pair<vector<int>,
+list<double> > should not take O(1).
    
 
-
    
-Change 23.3.4.4 [list.ops], paragraph 20 to:
    
+
    [Lillehammer: We agree it should be swappable.  Howard will
+  provide wording.]
    
 
-
    
-"Throws: Nothing unless an exception is thrown by *(i-1) == *i or
-pred(*(i-1), *i)."
    
 
-
    
-Comments to the new wording:
    
+
    [
+Post Oxford:  We got swap for pair but accidently
+missed tuple.  tuple::swap is being tracked by 522.
+]
    
 
-
    
-a) The wording regarding the conditions is identical to proposed
-23.3.4.4 [list.ops], paragraph 19. If 23.3.4.4 [list.ops],
-paragraph 19 is resolved in another way, the proposed wording need also
-additional review.
-b) The expression "(i - 1)" was left, but is expected that DR submitted
-by Thomas Mang regarding invalid iterator arithmetic expressions will
-take this into account.
-c) Typos fixed.
    
 
-
    
-Change 23.3.4.4 [list.ops], paragraph 21 to:
    
 
-
    
-"Complexity: If empty() == false, exactly size() - 1 applications of the
-corresponding predicate, otherwise no applications of the corresponding
-predicate."
    
 
+
    Proposed resolution:
    
 
    
-Comments to the new wording:
    
+Wording provided in
+N1856.
+
    
 
+
    Rationale:
    
 
    
-a) The new wording is supposed to also replace the proposed resolution
-of DR 315, which suffers from the problem of undefined "first" / "last".
+Recommend NAD, fixed by 
+N1856.
 
    
 
-
    
-5) References to other DRs:
    
 
-
    See DR 202.
-See DR 239.
-See DR 315.
-See DR submitted by Thomas Mang regarding invalid iterator arithmetic
-expressions.
    
 
 
 
-
    Proposed resolution:
    
-
-
-
    Rationale:
    
-
    "All implementations known to the author of this Defect Report
-comply with these assumption", and "no impact on current code is
-expected", i.e. there is no evidence of real-world confusion or
-harm.
    
+
    
+
    483. Heterogeneous equality and EqualityComparable
    
+
    Section: 25.3 [alg.nonmodifying], 25.4 [alg.modifying.operations] Status: Dup
+ Submitter: Peter Dimov Opened: 2004-09-20  Last modified: 2007-01-15
    
+
    View all issues with Dup status.
    
+
    Duplicate of: 283
    
+
    Discussion:
    
+
    c++std-lib-14262
    
 
+
    [lib.alg.find] requires T to be EqualityComparable:
    
 
+
    template <class InputIterator, class T>
+   InputIterator find(InputIterator first, InputIterator last,
+                      const T& value);
+
    
 
+
    
+However the condition being tested, as specified in the Effects
+clause, is actually *i == value, where i is an InputIterator.
+
    
 
+
    
+The two clauses are in agreement only if the type of *i is T, but this
+isn't necessarily the case. *i may have a heterogeneous comparison
+operator that takes a T, or a T may be convertible to the type of *i.
+
    
 
-
    
-
    493. Undefined Expression in Input Iterator Note Title
    
-
    Section: 24.2.2 [input.iterators] Status: NAD
- Submitter: Chris Jefferson Opened: 2004-12-13  Last modified: 2006-12-27
    
-
    View all other issues in [input.iterators].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
-
    1) In 24.1.1/3, the following text is currently present.
    
+
    Further discussion (c++std-lib-14264): this problem affects a
+  number of algorithsm in clause 25, not just find.  We
+  should try to resolve this problem everywhere it appears.
    
 
-
    "Note: For input iterators, a==b does not imply ++a=++b (Equality does
-not guarantee the substitution property or referential transparency)."
    
 
-
    However, when in Table 72, part of the definition of ++r is given as:
    
+
    Proposed resolution:
    
 
-
    "pre: r is dereferenceable.
-post: any copies of the previous value of r are no longer required
-either to be dereferenceable ..."
    
+
    [lib.alg.find]:
    
+
    
+   Remove [lib.alg.find]/1.
+
    
 
-
    While a==b does not imply that b is a copy of a, this statement should
-perhaps still be made more clear.
    
+
    [lib.alg.count]:
    
+
    
+   Remove [lib.alg.count]/1.
+
    
 
-
    2) There are no changes to intended behaviour
    
+
    [lib.alg.search]:
    
+
    
+   Remove "Type T is EqualityComparable (20.1.1), " from [lib.alg.search]/4.
+
    
 
-
    
-3) This Note should be altered to say "Note: For input iterators a==b,
-when its behaviour is defined ++a==++b may still be false (Equality does
-not guarantee the substitution property or referential transparency).
    
+
    [lib.alg.replace]:
    
 
+
    
+   
    
+   Remove [lib.alg.replace]/1.
+   Replace [lb.alg.replace]/2 with:
+   
    
 
+       
    
+       For every iterator i in the range [first, last) for which *i == value
+       or pred(*i) holds perform *i = new_value.
+       
    
 
-
    Proposed resolution:
    
+   
    
+   Remove the first sentence of /4.
+   Replace the beginning of /5 with:
+   
    
 
+       
    
+       For every iterator i in the range [result, result + (last -
+       first)), assign to *i either...
+       
    
 
-
    Rationale:
    
-
    This is descriptive text, not normative, and the meaning is clear.
    
+   
    (Note the defect here, current text says assign to i, not *i).
    
+
    
 
+
    [lib.alg.fill]:
    
 
+
    
+   
    
+   Remove "Type T is Assignable (23.1), " from /1.
+   Replace /2 with:
+   
    
 
+       
    
+       For every iterator i in the range [first, last) or [first, first + n),
+       perform *i = value.
+       
    
+
    
 
+
    [lib.alg.remove]:
    
+
    
+   Remove /1.
+   Remove the first sentence of /6.
+
    
 
-
    
-
    494. Wrong runtime complexity for associative container's insert and delete
    
-
    Section: 23.2.4 [associative.reqmts] Status: NAD
- Submitter: Hans B os Opened: 2004-12-19  Last modified: 2006-12-27
    
-
    View other active issues in [associative.reqmts].
    
-
    View all other issues in [associative.reqmts].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
-
    According to [lib.associative.reqmts] table 69, the runtime comlexity
-of insert(p, t) and erase(q) can be done in amortized constant time.
    
 
-
    It was my understanding that an associative container could be
-implemented as a balanced binary tree.
    
 
-
    For inser(p, t), you 'll have to iterate to p's next node to see if t
-can be placed next to p.  Furthermore, the insertion usually takes
-place at leaf nodes. An insert next to the root node will be done at
-the left of the root next node
    
+
    Rationale:
    
+
    Duplicate of (a subset of) issue 283.
    
 
-
    So when p is the root node you 'll have to iterate from the root to
-its next node, which  takes O(log(size)) time in a balanced tree.
    
 
-
    If you insert all values with insert(root, t) (where root is the
-root of the tree before insertion) then each insert takes O(log(size))
-time.  The amortized complexity per insertion will be O(log(size))
-also.
    
 
-
    For erase(q), the normal algorithm for deleting a node that has no
-empty left or right subtree, is to iterate to the next (or previous),
-which is a leaf node. Then exchange the node with the next and delete
-the leaf node.  Furthermore according to DR 130, erase should return
-the next node of the node erased.  Thus erasing the root node,
-requires iterating to the next node.
    
 
-
    Now if you empty a map by deleting the root node until the map is
-empty, each operation will take O(log(size)), and the amortized
-complexity is still O(log(size)).
    
 
-
    The operations can be done in amortized constant time if iterating
-to the next node can be done in (non amortized) constant time.  This
-can be done by putting all nodes in a double linked list.  This
-requires two extra links per node.  To me this is a bit overkill since
-you can already efficiently insert or erase ranges with erase(first,
-last) and insert(first, last).
    
 
+
    
+
    486. min/max CopyConstructible requirement is too strict
    
+
    Section: 25.5.7 [alg.min.max] Status: Dup
+ Submitter: Dave Abrahams Opened: 2004-10-13  Last modified: 2006-12-30
    
+
    View all other issues in [alg.min.max].
    
+
    View all issues with Dup status.
    
+
    Duplicate of: 281
    
+
    Discussion:
    
+
    A straightforward implementation of these algorithms does not need to
+copy T.
    
 
 
 
    Proposed resolution:
    
+
    drop the the words "and CopyConstructible" from paragraphs 1 and 4
    
 
 
 
    Rationale:
    
-
    Only "amortized constant" in special circumstances, and we believe
-  that's implementable. That is: doing this N times will be O(N), not
-  O(log N).
    
+
 
 
 
 
 
 
    
-
    499. Std. doesn't seem to require stable_sort() to be stable!
    
-
    Section: 25.5.1.2 [stable.sort] Status: NAD Editorial
- Submitter: Prateek Karandikar Opened: 2005-04-12  Last modified: 2008-03-13
    
-
    View all issues with NAD Editorial status.
    
+
    487. Allocator::construct is too limiting
    
+
    Section: X [allocator.requirements] Status: NAD
+ Submitter: Dhruv Matani Opened: 2004-10-17  Last modified: 2006-12-30
    
+
    View other active issues in [allocator.requirements].
    
+
    View all other issues in [allocator.requirements].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
-
    
-17.3.1.1 Summary
    
-
-
    
-1 The Summary provides a synopsis of the category, and introduces the 
-first-level subclauses. Each subclause also provides a summary, listing 
-the headers specified in the subclause and the library entities 
-provided in each header. 
-
    
 
    
-2 Paragraphs labelled "Note(s):" or "Example(s):" are informative, 
-other paragraphs are normative.
-
     
-
-
    So this means that a "Notes" paragraph wouldn't be normative. 
    
-
-
    
-25.3.1.2 stable_sort
+The standard's version of allocator::construct(pointer,
+const_reference) severely limits what you can construct using this
+function.  Say you can construct a socket from a file descriptor. Now,
+using this syntax, I first have to manually construct a socket from
+the fd, and then pass the constructed socket to the construct()
+function so it will just to an uninitialized copy of the socket I
+manually constructed. Now it may not always be possible to copy
+construct a socket eh! So, I feel that the changes should go in the
+allocator::construct(), making it:
 
    
-
    template<class RandomAccessIterator> 
-void stable_sort(RandomAccessIterat or first, RandomAccessIterator last); 
-
-template<class RandomAccessIterator, class Compare> 
-void stable_sort(RandomAccessIterat or first, RandomAccessIterator last, Compare comp);
+
        template<typename T>
+    struct allocator{
+      template<typename T1>
+      void construct(pointer T1 const& rt1);
+    };
 
    
-
    
-1 Effects: Sorts the elements in the range [first, last).
-
    
-
    
-2 Complexity: It does at most N(log N)^2 (where N == last - first) 
-comparisons; if enough extra memory is available, it is N log N.
-
    
-
    
-3 Notes: Stable: the relative order of the equivalent elements is 
-preserved. 
-
     
-
-
    
-The Notes para is informative, and nowhere else is stability mentioned above. 
-
    
 
 
    
-Also, I just searched for the word "stable" in my copy of the Standard. 
-and the phrase "Notes: Stable: the relative order of the elements..." 
-is repeated several times in the Standard library clauses for 
-describing various functions. How is it that stability is talked about 
-in the informative paragraph? Or am I missing something obvious? 
+Now, the ctor of the class T which matches the one that takes a T1 can
+be called! Doesn't that sound great?
 
    
 
 
 
    Proposed resolution:
    
-
    
-
    
 
 
 
    Rationale:
    
-
    
-This change has already been made.
-
    
+
    NAD. STL uses copying all the time, and making it possible for
+  allocators to construct noncopyable objects is useless in the
+  absence of corresponding container changes. We might consider this
+  as part of a larger redesign of STL.
    
 
 
 
 
 
 
    
-
    500. do_length cannot be implemented correctly
    
-
    Section: 22.4.1.5 [locale.codecvt.byname] Status: NAD
- Submitter: Krzysztof Żelechowski Opened: 2005-05-24  Last modified: 2008-03-13
    
-
    View all other issues in [locale.codecvt.byname].
    
+
    489. std::remove / std::remove_if wrongly specified
    
+
    Section: 25.4.8 [alg.remove] Status: NAD
+ Submitter: Thomas Mang Opened: 2004-12-12  Last modified: 2006-12-27
    
+
    View all other issues in [alg.remove].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
-
      
-
    1. codecvt::do_length is of type int;
      2. 
-
    2. it is assumed to be sort-of returning from_next - from of type ptrdiff_t;
      3. 
-
    3. ptrdiff_t cannot be cast to an int without data loss.
      4. 
-
    
-
    
-Contradiction.
+
    In Section 25.2.7 [lib.alg.remove], paragraphs 1 to 5 describe the
+behavior of the mutating sequence operations std::remove and
+std::remove_if. However, the wording does not reflect the intended
+behavior [Note: See definition of intended behavior below] of these
+algorithms, as it is known to the C++ community [1].
 
    
 
 
-
    Proposed resolution:
    
-
    
-
    
 
+
    1) Analysis of current wording:
    
 
 
+
    25.2.7 [lib.alg.remove], paragraph 2:
    
 
-
-
    
-
    501. Proposal: strengthen guarantees of lib.comparisons
    
-
    Section: 20.7.3 [base] Status: NAD
- Submitter: Me <anti_spam_email2003@yahoo.com> Opened: 2005-06-07  Last modified: 2008-03-13
    
-
    View all other issues in [base].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
-
    
-"For templates greater, less, greater_equal, and less_equal,
-the specializations for any pointer type yield a total order, even if
-the built-in operators <, >, <=, >= do not."
-
    
+
    Current wording says:
+"Effects: Eliminates all the elements referred to by iterator i in the
+range [first, last) for which the following corresponding conditions
+hold: *i == value, pred(*i) != false."
    
 
 
    
-The standard should do much better than guarantee that these provide a
-total order, it should guarantee that it can be used to test if memory
-overlaps, i.e. write a portable memmove. You can imagine a platform
-where the built-in operators use a uint32_t comparison (this tests for
-overlap on this platform) but the less<T*> functor is allowed to be
-defined to use a int32_t comparison. On this platform, if you use
-std::less with the intent of making a portable memmove, comparison on
-an array that straddles the 0x7FFFFFFF/0x8000000 boundary can give
-incorrect results.
+This sentences expresses specifically that all elements denoted by the
+(original) range [first, last) for which the corresponding condition
+hold will be eliminated. Since there is no formal definition of the term
+"eliminate" provided, the meaning of "eliminate" in everyday language
+implies that as postcondition, no element in the range denoted by
+[first, last) will hold the corresponding condition on reiteration over
+the range [first, last).
 
    
 
-
-
    Proposed resolution:
    
 
    
-Add a footnote to 20.5.3/8 saying:
+However, this is neither the intent [Note: See definition of intended
+behavior below] nor a general possible approach. It can be easily proven
+that if all elements of the original range[first, last) will hold the
+condition, it is not possible to substitute them by an element for which
+the condition will not hold.
 
    
 
-
    
-Given a p1 and p2 such that p1 points to N objects of type T and p2
-points to M objects of type T. If [p1,p1+N) does not overlap [p2,p2+M),
-less returns the same value when comparing all pointers in [p1,p1+N) to
-all pointers in [p2,p2+M). Otherwise, there is a value Q and a value R
-such that less returns the same value when comparing all pointers in
-[p1,p1+Q) to all pointers in [p2,p2+R) and an opposite value when
-comparing all pointers in [p1+Q,p1+N) to all pointers in [p2+R,p2+M).
-For the sake of completeness, the null pointer value (4.10) for T is
-considered to be an array of 1 object that doesn't overlap with any
-non-null pointer to T. less_equal, greater, greater_equal, equal_to,
-and not_equal_to give the expected results based on the total ordering
-semantics of less. For T of void, treat it as having similar semantics
-as T of char i.e. less<cv T*>(a, b) gives the same results as less<cv
-void*>(a, b) which gives the same results as less<cv char*>((cv
-char*)(cv void*)a, (cv char*)(cv void*)b).
-
    
+
+
    25.2.7 [lib.alg.remove], paragraph 3:
    
 
 
    
-I'm also thinking there should be a footnote to 20.5.3/1 saying that if
-A and B are similar types (4.4/4), comp<A>(a,b) returns the same value
-as comp<B>(a,b) (where comp is less, less_equal, etc.). But this might
-be problematic if there is some really funky operator overloading going
-on that does different things based on cv (that should be undefined
-behavior if somebody does that though). This at least should be
-guaranteed for all POD types (especially pointers) that use the
-built-in comparison operators.
+Current wording says:
+"Returns: The end of the resulting range."
 
    
 
-
-
-
    Rationale:
    
 
    
-less is already required to provide a strict weak ordering which is good enough
-to detect overlapping memory situations.
+The resulting range is not specified. In combination with 25.2.7
+[lib.alg.remove], paragraph 2, the only reasonable interpretation of
+this so-called resulting range is the range [first,last) - thus
+returning always the ForwardIterator 'last' parameter.
 
    
 
 
-
-
-
-
    
-
    504. Integer types in pseudo-random number engine requirements
    
-
    Section: X [rand.req], TR1 5.1.1 [tr.rand.req] Status: NAD Editorial
- Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
-
    View all other issues in [rand.req].
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
 
    
-In [tr.rand.req], Paragraph 2 states that "... s is a value of integral type,
-g is an ... object returning values of unsigned integral type ..."
+25.2.7 [lib.alg.remove], paragraph 4:
 
    
 
+
    
+Current wording says:
+"Notes: Stable: the relative order of the elements that are not removed
+is the same as their relative order in the original range"
+
    
 
-
    Proposed resolution:
    
 
    
-In 5.1.1 [tr.rand.req], Paragraph 2 replace
+This sentences makes use of the term "removed", which is neither
+specified, nor used in a previous paragraph (which uses the term
+"eliminate"), nor unamgiuously separated from the name of the algorithm.
 
    
 
-
    
-... s is a value of integral type, g is an lvalue of a type other than X that
-defines a zero-argument function object returning values of unsigned integral type
-unsigned long int,
-...
-
    
+
+
    2) Description of intended behavior:
    
 
 
    
-In 5.1.1 [tr.rand.seq], Table 16, replace in the line for X(s)
+For the rest of this Defect Report, it is assumed that the intended
+behavior was that all elements of the range [first, last) which do not
+hold the condition *i == value (std::remove) or  pred(*i) != false
+(std::remove_if)], call them s-elements [Note: s...stay], will be placed
+into a contiguous subrange of [first, last), denoted by the iterators
+[first, return value). The number of elements in the resulting range
+[first, return value) shall be equal to the number of s-elements in the
+original range [first, last). The relative order of the elements in the
+resulting subrange[first, return value) shall be the same as the
+relative order of the corresponding elements in the original range. It
+is undefined whether any elements in the resulting subrange [return
+value, last) will hold the corresponding condition, or not.
 
    
 
-
    
-creates an engine with the initial internal state
-determined by static_cast<unsigned long>(s)
-
    
-
-
    [
-Mont Tremblant:  Both s and g should be unsigned long.
-This should refer to the constructor signatures. Jens  provided wording post Mont Tremblant.
-]
    
+
    
+All implementations known to the author of this Defect Report comply
+with this intent. Since the intent  of the behavior (contrary to the
+current wording) is also described in various utility references serving
+the C++ community [1], it is not expected that fixing the paragraphs
+will influence current code - unless the code relies on the behavior as
+it is described by current wording and the implementation indeed
+reflects the current wording, and not the intent.
+
    
 
 
-
    [
-Berlin:  N1932 adopts the proposed resolution:  see 26.3.1.3/1e and Table 3 row 2. Moved
-to Ready.
-]
    
 
+
    3) Proposed fixes:
    
 
 
+
    Change 25.2.7 [lib.alg.remove], paragraph 2 to:
    
 
-
    Rationale:
    
 
    
-Jens:  Just requiring X(unsigned long) still makes it possible
-for an evil library writer to also supply a X(int) that does something
-unexpected.  The wording above requires that X(s) always performs
-as if X(unsigned long) would have been called.  I believe that is
-sufficient and implements our intentions from Mont Tremblant.  I
-see no additional use in actually requiring a X(unsigned long)
-signature.  u.seed(s) is covered by its reference to X(s), same
-arguments.
+"Effect: Places all the elements referred to by iterator i in the range
+[first, last) for which the following corresponding conditions hold :
+!(*i == value), pred(*i) == false into the subrange [first, k) of the
+original range, where k shall denote a value of type ForwardIterator. It
+is undefined whether any elements in the resulting subrange [k, last)
+will hold the corresponding condition, or not."
 
    
 
+
    Comments to the new wording:
    
 
-
    [
-Portland:  Subsumed by N2111.
-]
    
+
    
+a) "Places" has no special meaning, and the everyday language meaning
+should fit.
+b) The corresponding conditions were negated compared to the current
+wording, becaue the new wording requires it.
+c) The wording "of the original range" might be redundant, since any
+subrange starting at 'first' and containing no more elements than the
+original range is implicitly a subrange of the original range [first,
+last).
+d) The iterator k was introduced instead of "return value" in order to
+avoid a cyclic dependency on 25.2.7/3. The wording ", where k shall
+denote a value of type ForwardIterator" might be redundant, because it
+follows implicitly by 25.2.7/3.
+e) "Places" does, in the author's opinion, explicitly forbid duplicating
+any element holding the corresponding condition in the original range
+[first, last) within the resulting range [first, k). If there is doubt
+this term might be not unambiguous regarding this, it is suggested that
+k is specified more closely by the following wording: "k shall denote a
+value of type ForwardIterator [Note: see d)] so that k - first is equal
+to the number of elements in the original range [first, last) for which
+the corresponding condition did hold". This could also be expressed as a
+separate paragraph "Postcondition:"
+f) The senctence "It is undefined whether any elements in the resulting
+subrange [k, last) will hold the corresponding condition, or not." was
+added consciously so the term "Places" does not imply if the original
+range [first, last) contains n elements holding the corresponding
+condition, the identical range[first, last) will also contain exactly n
+elements holding the corresponding condition after application of the
+algorithm.
+
    
 
+
    
+Change 25.2.7 [lib.alg.remove], paragraph 3 to:
 
+"Returns: The iterator k."
+
    
 
+
    
+Change 25.2.7 [lib.alg.remove], paragraph 4 to:
 
+"Notes: Stable: the relative order of the elements that are placed into
+the subrange [first, return value) shall be the same as their relative
+order was in the original range [first, last) prior to application of
+the algorithm."
+
    
 
-
    
-
    506. Requirements of Distribution parameter for variate_generator
    
-
    Section: 26.5 [rand], TR1 5.1.3 [tr.rand.var] Status: NAD
- Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
-
    View other active issues in [rand].
    
-
    View all other issues in [rand].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
 
    
-Paragraph 3 requires that template argument U (which corresponds to template
-parameter Engine) satisfy all uniform random number generator requirements.
-However, there is no  analogous requirement regarding the template argument
-that corresponds to template parameter Distribution.  We believe there should
-be, and that it should require that this template argument satisfy all random
-distribution requirements.
+Comments to the new wording:
 
    
 
-
-
    Proposed resolution:
    
 
    
-Consequence 1: Remove the precondition clauses [tr.rand.var]/16 and /18.
+a) the wording "was ...  prior to application of the algorithm" is used
+to explicitly distinguish the original range not only by means of
+iterators, but also by a 'chronological' factor from the resulting range
+[first, return value). It might be redundant.
 
    
+
 
    
-Consequence 2: Add max() and min() functions to those distributions that
-do not already have them.
+[1]:
+The wording of these references is not always unambiguous, and provided
+examples partially contradict verbal description of the algorithms,
+because the verbal description resembles the problematic wording of
+ISO/IEC 14882:2003.
 
    
 
-
    [
-Mont Tremblant: Jens reccommends NAD, min/max not needed everywhere.
-Marc supports having min and max to satisfy generic programming interface.
-]
    
-
 
+
    Proposed resolution:
    
 
 
 
    Rationale:
    
-
    Berlin:  N1932 makes this moot: variate_generator has been eliminated.
    
+
    The LWG believes that the standard is sufficiently clear, and that
+  there is no evidence of any real-world confusion about this point.
    
 
 
 
 
 
 
    
-
    509. Uniform_int template parameters
    
-
    Section: 26.5.8.1 [rand.dist.uni], TR1 5.1.7.1 [tr.rand.dist.iunif] Status: NAD
- Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
-
    View all other issues in [rand.dist.uni].
    
+
    490. std::unique wrongly specified
    
+
    Section: 25.4.9 [alg.unique] Status: NAD
+ Submitter: Thomas Mang Opened: 2004-12-12  Last modified: 2006-12-27
    
+
    View all other issues in [alg.unique].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
-
    
-In [tr.rand.dist.iunif] the uniform_int distribution currently has a single
-template parameter, IntType, used as the input_type and as the result_type
-of the distribution.  We believe there is no reason to conflate these types
-in this way.
-
    
-
-
-
    Proposed resolution:
    
-
    
-We recommend that there be a second template  parameter to
-reflect the distribution's input_type, and that the existing first template
-parameter continue to reflect (solely) the result_type:
-
    
-
    template< class IntType = int, UIntType = unsigned int >
-class uniform_int
-{
-public:
-  // types
-  typedef  UIntType  input_type;
-  typedef  IntType   result_type;
-
    
+
    In Section 25.2.8 [lib.alg.unique], paragraphs 1 to 3 describe the
+behavior of the mutating sequence operation std::unique. However, the
+wording does not reflect the intended behavior [Note: See definition of
+intended behavior below] of these algorithms, as it is known to the C++
+community [1].
    
 
-
    [
-Berlin: Moved to NAD.  N1932 makes this moot: the input_type template parameter has been
-eliminated.
-]
    
 
 
+
    1) Analysis of current wording:
    
 
 
+
    25.2.8 [lib.alg.unique], paragraph 1:
    
 
+
    
+Current wording says:
+"Effects: Eliminates all but the first element from every consecutive
+group of equal elements referred to by the iterator i in the range
+[first, last) for which the following corresponding conditions hold: *i
+== *(i - 1) or pred(*i, *(i -1)) != false"
+
    
 
+
    
+This sentences expresses specifically that all elements denoted by the
+(original) range [first, last) which are not but the first element from
+a consecutive group of equal elements (where equality is defined as *i
+== *(i - 1) or pred(*i, *(i - 1)) ! = false) [Note: See DR 202], call
+them r-elements [Note: r...remove], will be eliminated. Since there is
+no formal definition of the term "eliminate" provided, it is undefined
+how this "elimination" takes place. But the meaning of "eliminate" in
+everyday language seems to disallow explicitly that after application of
+the algorithm, any r-element will remain at any position of the range
+[first, last) [2].
+
    
 
-
    
-
    510. Input_type for bernoulli_distribution
    
-
    Section: 26.5.8.2 [rand.dist.bern], TR1 5.1.7.2 [tr.rand.dist.bern] Status: NAD
- Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
 
    
-In [tr.rand.dist.bern] the distribution currently requires;
+Another defect in the current wording concerns the iterators used to
+compare two elements for equality: The current wording contains the
+expression "(i - 1)", which is not covered by 25/9 [Note: See DR
+submitted by Thomas Mang regarding invalid iterator arithmetic
+expressions].
 
    
-
    typedef  int  input_type;
-
    
 
 
-
    Proposed resolution:
    
 
    
-We believe this is an unfortunate choice, and recommend instead:
+25.2.8 [lib.alg.unique], paragraph 2:
 
    
-
    typedef  unsigned int  input_type;
-
    
+
    Current wording says:
+"Returns: The end of the resulting range."
    
 
-
    [
-Berlin:  Moved to NAD. N1932 makes this moot: the input_type template parameter has been
-eliminated.
-]
    
+
    
+The resulting range is not specified. In combination with 25.2.8
+[lib.alg.unique], paragraph 1, one reasonable interpretation (in the
+author's opinion even the only possible interpretation) of this
+so-called resulting range is the range [first, last) - thus returning
+always the ForwardIterator 'last' parameter.
+
    
 
+
    2) Description of intended behavior:
    
 
+
    
+For the rest of this Defect Report, it is assumed that the intended
+behavior was that all elements denoted by the original range [first,
+last) which are the first element from a consecutive group of elements
+for which the corresponding conditions: *(i-1) == *i (for the version of
+unique without a predicate argument) or pred(*(i-1), *i) ! = false (for
+the version of unique with a predicate argument) [Note: If such a group
+of elements consists of only a single element, this is also considered
+the first element] [Note: See resolutions of DR 202], call them
+s-elements [Note: s...stay], will be placed into a contiguous subrange
+of [first, last), denoted by the iterators [first, return value). The
+number of elements in the resulting range [first, return value) shall be
+equal to the number of s-elements in the original range [first, last).
+Invalid iterator arithmetic expressions are expected to be resolved as
+proposed in DR submitted by Thomas Mang regarding invalid iterator
+arithmetic expressions. It is also assumed by the author that the
+relative order of the elements in the resulting subrange [first, return
+value) shall be the same as the relative order of the corresponding
+elements (the s-elements) in the original range [Note: If this was not
+intended behavior, the additional proposed paragraph about stable order
+will certainly become obsolete].
+Furthermore, the resolutions of DR 202 are partially considered.
+
    
 
+
    
+All implementations known to the author of this Defect Report comply
+with this intent [Note: Except possible effects of DR 202]. Since this
+intent of the behavior (contrary to the current wording) is also
+described in various utility references serving the C++ community [1],
+it is not expected that fixing the paragraphs will influence current
+code [Note: Except possible effects of DR 202] - unless the code relies
+on the behavior as it is described by current wording and the
+implementation indeed reflects the current wording, and not the intent.
+
    
 
 
 
+
    3) Proposed fixes:
    
 
-
    
-
    511. Input_type for binomial_distribution
    
-
    Section: 26.5.8 [rand.dist], TR1 5.1.7.5 [tr.rand.dist.bin] Status: NAD
- Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
-
    View all other issues in [rand.dist].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
 
    
-Unlike all other distributions in TR1, this binomial_distribution has an
-implementation-defined  input_type.  We believe this is an unfortunate choice,
-because it hinders users from writing portable code.  It also hinders the
-writing of compliance tests.  We recommend instead:
+Change 25.2.8 [lib.alg.unique], paragraph 1 to:
 
    
-
    typedef  RealType  input_type;
-
    
+
 
    
-While this choice is somewhat arbitrary (as it was for some of the other
-distributions), we make  this particular choice because (unlike all other
-distributions) otherwise this template would not publish its RealType
-argument and so users could not write generic code that accessed this
-second template parameter.  In this respect, the choice is consistent with
-the other distributions in  TR1. 
+"Effect: Places the first element from every consecutive group of
+elements, referred to by the iterator i in the range [first, last), for
+which the following conditions hold: *(i-1) == *i (for the version of
+unique without a predicate argument) or pred(*(i -1), *i) != false (for
+the version of unique with a predicate argument), into the subrange
+[first, k) of the original range, where k shall denote a value of type
+ForwardIterator."
 
    
+
+
    Comments to the new wording:
    
+
 
    
-We have two reasons for recommending that a real type be specified instead.
-One reason is  based specifically on characteristics of binomial distribution
-implementations, while the other is based on mathematical characteristics of
-probability distribution functions in general.
+a) The new wording was influenced by the resolutions of DR 202. If DR
+202 is resolved in another way, the proposed wording need also
+additional review.
+b) "Places" has no special meaning, and the everyday language meaning
+should fit.
+c) The expression "(i - 1)" was left, but is expected that DR submitted
+by Thomas Mang regarding invalid iterator arithmetic expressions will
+take this into account.
+d) The wording "(for the version of unique without a predicate
+argument)" and "(for the version of unique with a predicate argument)"
+was added consciously for clarity and is in resemblence with current
+23.2.2.4 [lib.list.ops], paragraph 19. It might be considered redundant.
+e) The wording "of the original range" might be redundant, since any
+subrange starting at first and containing no more elements than the
+original range is implicitly a subrange of the original range [first,
+last).
+f) The iterator k was introduced instead of "return value" in order to
+avoid a cyclic dependency on 25.2.8 [lib.alg.unique], paragraph 2. The
+wording ", where k shall denote a value of type ForwardIterator" might
+be redundant, because it follows implicitly by 25.2.8 [lib.alg.unique],
+paragraph 2.
+g) "Places" does, in the author's opinion, explicitly forbid duplicating
+any s-element in the original range [first, last) within the resulting
+range [first, k). If there is doubt this term might be not unambiguous
+regarding this, it is suggested that k is specified more closely by the
+following wording: "k shall denote a value of type ForwardIterator
+[Note: See f)] so that k - first is equal to the number of elements in
+the original range [first, last) being the first element from every
+consecutive group of elements for which the corresponding condition did
+hold". This could also be expressed as a separate paragraph
+"Postcondition:".
+h) If it is considered that the wording is unclear whether it declares
+the element of a group which consists of only a single element
+implicitly to be the first element of this group [Note: Such an
+interpretation could eventually arise especially in case last - first ==
+1] , the following additional sentence is proposed: "If such a group of
+elements consists of only a single element, this element is also
+considered the first element."
 
    
+
 
    
-Implementations of binomial distributions commonly use Stirling approximations
-for values in certain ranges.  It is far more natural to use real values to
-represent these approximations than it would be to use integral values to do
-so.  In other ranges, implementations reply on the Bernoulli  distribution to
-obtain values.  While TR1's bernoulli_distribution::input_type is specified as
-int, we believe this would be better specified as double.
+Change 25.2.8 [lib.alg.unique], paragraph 2 to:
+"Returns: The iterator k."
 
    
+
 
    
-This brings us to our main point:  The notion of a random distribution rests
-on the notion of a cumulative distribution function, which in turn mathematically
-depends on a continuous dependent variable.  Indeed, such a distribution function
-would be meaningless if it depended on  discrete values such as integers - and this
-remains true even if the distribution function were to take discrete steps.
+Add a separate paragraph "Notes:" as 25.2.8 [lib.alg.unique], paragraph
+2a or 3a, or a separate paragraph "Postcondition:" before 25.2.8
+[lib.alg.unique], paragraph 2 (wording inside {} shall be eliminated if
+the preceding expressions are used, or the preceding expressions shall
+be eliminated if wording inside {} is used):
 
    
+
 
    
-Although this note is specifically about binomial_distribution::input_type,
-we intend to recommend that all of the random distributions input_types be
-specified as a real type (either a RealType template parameter, or double,
-as appropriate).
+"Notes:{Postcondition:} Stable: the relative order of the elements that
+are placed into the subrange [first, return value {k}) shall be the same
+as their relative order was in the original range [first, last) prior to
+application of the algorithm."
 
    
+
+
    Comments to the new wording:
    
+
 
    
-Of the nine distributions in TR1, four already have this characteristic
-(uniform_real, exponential_distribution, normal_distribution, and
-gamma_distribution).  We have already argued the case for the binomial the
-remaining four distributions.
+a) It is assumed by the author that the algorithm was intended to be
+stable.
+In case this was not the intent, this paragraph becomes certainly
+obsolete.
+b) The wording "was ...  prior to application of the algorithm" is used
+to explicitly distinguish the original range not only by means of
+iterators, but also by a 'chronological' factor from the resulting range
+[first, return value). It might be redundant.
 
    
+
 
    
-In the case of uniform_int, we believe that the calculations to produce an
-integer result in a  specified range from an integer in a different specified
-range is best done using real arithmetic.  This is because it involves a
-product, one of whose terms is the ratio of the extents of the two ranges.
-Without real arithmetic, the results become less uniform: some numbers become
-more  (or less) probable that they should be.  This is, of course, undesireable
-behavior in a uniform distribution.
+25.2.8 [lib.alg.unique], paragraph 3:
 
    
+
    See DR 239.
    
+
 
    
-Finally, we believe that in the case of the bernoulli_distribution (briefly
-mentioned earlier), as well as the cases of the geometric_distribution and the
-poisson_distribution, it would be far more natural to have a real input_type.
-This is because the most natural computation involves the  random number
-delivered and the distribution's parameter p (in the case of bernoulli_distribution,
-for example, the computation is a comparison against p), and p is already specified
-in each case as having some real type.
+4) References to other DRs:
 
    
 
+
    
+See DR 202, but which does not address any of the problems described in
+this Defect Report [Note: This DR is supposed to complement DR 202].
+See DR 239.
+See DR submitted by Thomas Mang regarding invalid iterator arithmetic
+expressions.
+
    
 
-
    Proposed resolution:
    
-
    typedef  RealType  input_type;
-
    
-
-
    [
-Berlin:  Moved to NAD.  N1932 makes this moot: the input_type template parameter has been
-eliminated.
-]
    
-
-
-
-
-
-
-
    
-
    512. Seeding subtract_with_carry_01 from a single unsigned long
    
-
    Section: 26.5.3 [rand.eng], TR1 5.1.4.4 [tr.rand.eng.sub1] Status: NAD Editorial
- Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
-
    View all other issues in [rand.eng].
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
 
    
-Paragraph 8 specifies the algorithm by which a subtract_with_carry_01  engine
-is to be seeded given a single unsigned long.  This algorithm is seriously
-flawed in the case where the engine parameter w (also known as word_size)
-exceeds 31 [bits].  The key part of the paragraph reads:
+[1]:
+The wording of these references is not always unambiguous, and provided
+examples partially contradict verbal description of the algorithms,
+because the verbal description resembles the problematic wording of
+ISO/IEC 14882:2003.
 
    
-
    
-sets x(-r) ... x(-1) to (lcg(1)*2**(-w)) mod 1
-
    
+
 
    
-and so forth. 
+[2]:
+Illustration of conforming implementations according to current wording:
 
    
+
 
    
-Since the specified linear congruential engine, lcg, delivers numbers with
-a maximum of 2147483563 (just a shade under 31 bits), then when w is, for
-example, 48, each of the x(i) will be less than 2**-17.  The consequence
-is that roughly the first 400 numbers delivered will be  conspicuously
-close to either zero or one.
+One way the author of this DR considers how this "elimination" could be
+achieved by a conforming implementation according to current wording is
+by substituting each r-element by _any_ s-element [Note: s...stay; any
+non-r-element], since all r-elements are "eliminated".
 
    
+
 
    
-Unfortunately, this is not an innocuous flaw:  One of the predefined engines
-in [tr.rand.predef],  namely ranlux64_base_01, has w = 48 and would exhibit
-this poor behavior, while the original N1378 proposal states that these
-pre-defined engines are intended to be of "known good properties."
+In case of a sequence consisting of elements being all 'equal' [Note:
+See DR 202], substituting each r-element by the single s-element is the
+only possible solution according to current wording.
 
    
 
 
 
    Proposed resolution:
    
-
    
-In 5.1.4.4 [tr.rand.eng.sub1], replace the "effects" clause for
-void seed(unsigned long value = 19780503) by
-
    
 
-
    
-Effects: If value == 0, sets value to 19780503. In any
-case, with a linear congruential generator lcg(i) having parameters
-mlcg = 2147483563, alcg = 40014,
-clcg = 0, and lcg(0) = value,
-sets carry(-1) and x(-r) … x(-1)
-as if executing
    
 
-
    
-linear_congruential<unsigned long, 40014, 0, 2147483563> lcg(value);
-seed(lcg);
-
    
+
    Rationale:
    
+
    The LWG believes the standard is sufficiently clear. No
+implementers get it wrong, and changing it wouldn't cause any code to
+change, so there is no real-world harm here.
    
 
-
    
-to (lcg(1) · 2-w) mod 1
-… (lcg(r) · 2-w) mod 1,
-respectively. If x(-1) == 0, sets carry(-1) = 2-w,
-else sets carry(-1) = 0.
    
-
    
 
-
    [
-Jens provided revised wording post Mont Tremblant.
-]
    
 
 
-
    [
-Berlin: N1932 adopts the originally-proposed resolution of the issue.
-Jens's supplied wording is a clearer description of what is
-intended.  Moved to Ready.
-]
    
 
+
    
+
    491. std::list<>::unique incorrectly specified
    
+
    Section: 23.3.4.4 [list.ops] Status: NAD
+ Submitter: Thomas Mang Opened: 2004-12-12  Last modified: 2007-02-19
    
+
    View all other issues in [list.ops].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    In Section 23.3.4.4 [list.ops], paragraphs 19 to 21 describe the
+behavior of the std::list<T, Allocator>::unique operation. However, the
+current wording is defective for various reasons.
    
 
 
 
-
    Rationale:
    
 
    
-Jens: I'm using an explicit type here, because fixing the
-prose would probably not qualify for the (with issue 504 even
-stricter) requirements we have for seed(Gen&).
+1) Analysis of current wording:
 
    
 
-
    [
-Portland:  Subsumed by N2111.
-]
    
+
    23.3.4.4 [list.ops], paragraph 19:
    
 
+
    
+Current wording says:
+"Effects:  Eliminates all but the first element from every consecutive
+group of equal elements referred to by the iterator i in the range
+[first + 1, last) for which *i == *(i - 1) (for the version of unique
+with no argument) or pred(*i, *(i -1)) (for the version of unique with a
+predicate argument) holds."
    
 
+
    
+This sentences makes use of the undefined term "Eliminates". Although it
+is, to a certain degree, reasonable to consider the term "eliminate"
+synonymous with "erase", using "Erase" in the first place, as the
+wording of 23.3.4.4 [list.ops], paragraph 15 does, would be clearer.
    
 
+
    
+The range of the elements referred to by iterator i is "[first + 1,
+last)". However, neither "first" nor "last" is defined.
    
 
+
    
+The sentence makes three times use of iterator arithmetic expressions (
+"first + 1", "*i == *(i - 1)", "pred(*i, *(i -1))" ) which is not
+defined for bidirectional iterator [see DR submitted by Thomas Mang
+regarding invalid iterator arithmetic expressions].
    
 
+
    
+The same problems as pointed out in DR 202 (equivalence relation / order
+of arguments for pred()) apply to this paragraph.
    
 
-
    
-
    513. Size of state for subtract_with_carry_01
    
-
    Section: 26.5.3 [rand.eng], TR1 5.1.4.4 [tr.rand.eng.sub1] Status: NAD Editorial
- Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
-
    View all other issues in [rand.eng].
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
 
    
-Paragraph 3 begins:
+23.3.4.4 [list.ops], paragraph 20:
 
    
-
    
-The size of the state is r.
-
    
+
 
    
-However, this is not quite consistent with the remainder of the paragraph
-which specifies a total  of nr+1 items in the textual representation of
-the state.  We recommend the sentence be corrected to match:
+Current wording says:
+"Throws: Nothing unless an exception in thrown by *i == *(i-1) or
+pred(*i, *(i - 1))"
    
+
+
    
+The sentence makes two times use of invalid iterator arithmetic
+expressions ( "*i == *(i - 1)", "pred(*i, *(i -1))" ).
 
    
-
    
-The size of the state is nr+1.
-
    
 
    
-To give meaning to the coefficient n, it may be also desirable to move
-n's definition from later in the paragraph.  Either of the following
-seem reasonable formulations:
+[Note: Minor typos: "in" / missing dot at end of sentence.]
 
    
-
    
-With n=..., the size of the state is nr+1.
-
    
-
    
-The size of the state is nr+1, where n=... .
-
    
 
+
    
+23.3.4.4 [list.ops], paragraph 21:
    
 
+
    
+Current wording says:
+"Complexity: If the range (last - first) is not empty, exactly (last -
+first) - 1 applications of the corresponding predicate, otherwise no
+application of the predicate.
    
 
-
    Proposed resolution:
    
-
    [
-Jens:  I plead for "NAD" on the grounds that "size of state" is only
-used as an argument for big-O complexity notation, thus
-constant factors and additions don't count.
-]
    
+
    
+See DR 315 regarding "(last - first)" not yielding a range.
    
 
+
    
+Invalid iterator arithmetic expression "(last - first) - 1" left .
    
 
-
    [
-Berlin: N1932 adopts the proposed NAD.
-]
    
 
+
    2) Description of intended behavior:
    
 
+
    
+For the rest of this Defect Report, it is assumed that "eliminate" is
+supposed to be synonymous to "erase", that "first" is equivalent to an
+iterator obtained by a call to begin(), "last" is equivalent to an
+iterator obtained by a call to end(), and that all invalid iterator
+arithmetic expressions are resolved as described in DR submitted by
+Thomas Mang regarding invalid iterator arithmetic expressions.
    
 
+
    
+Furthermore, the resolutions of DR 202 are considered regarding
+equivalence relation and order of arguments for a call to pred.
    
 
+
    
+All implementations known to the author of this Defect Report comply
+with these assumptions, apart from the impact of the alternative
+resolution of DR 202. Except for the changes implied by the resolutions
+of DR 202, no impact on current code is expected.
    
 
+
    
+3) Proposed fixes:
    
 
+
    
+Change 23.3.4.4 [list.ops], paragraph 19 to:
    
 
-
    
-
    514. Size of state for subtract_with_carry
    
-
    Section: 26.5.3.3 [rand.eng.sub], TR1 5.1.4.3 [tr.rand.eng.sub] Status: NAD Editorial
- Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
 
    
-Paragraph 2 begins:
-
    
-
    
-The size of the state is r.
-
    
+"Effect: Erases all but the first element from every consecutive group
+of elements, referred to by the iterator i in the range [begin(),
+end()), for which the following conditions hold: *(i-1) == *i (for the
+version of unique with no argument) or pred(*(i-1), *i) != false (for
+the version of unique with a predicate argument)."
    
+
 
    
-However, the next sentence specifies a total of r+1 items in the textual
-representation of the state,  r specific x's as well as a specific carry.
-This makes a total of r+1 items that constitute the size of the state,
-rather than r.
-
    
+Comments to the new wording:
    
 
+
    
+a) The new wording was influenced by DR 202 and the resolutions
+presented there. If DR 202 is resolved in another way, the proposed
+wording need also additional review.
+b) "Erases" refers in the author's opinion unambiguously to the member
+function "erase". In case there is doubt this might not be unamgibuous,
+a direct reference to the member function "erase" is suggested [Note:
+This would also imply a change of 23.3.4.4 [list.ops], paragraph
+15.].
+c) The expression "(i - 1)" was left, but is expected that DR submitted
+by Thomas Mang regarding invalid iterator arithmetic expressions will
+take this into account.
+d) The wording "(for the version of unique with no argument)" and "(for
+the version of unique with a predicate argument)" was kept consciously
+for clarity.
+e) "begin()" substitutes "first", and "end()" substitutes "last". The
+range need adjustment from "[first + 1, last)" to "[begin(), end())" to
+ensure a valid range in case of an empty list.
+f) If it is considered that the wording is unclear whether it declares
+the element of a group which consists of only a single element
+implicitly to be the first element of this group [Note: Such an
+interpretation could eventually arise especially in case size() == 1] ,
+the following additional sentence is proposed: "If such a group of
+elements consists of only a single element, this element is also
+considered the first element."
    
 
-
    Proposed resolution:
    
 
    
-We recommend the sentence be corrected to match:
-
    
-
    
- The size of the state is r+1.
-
    
+Change 23.3.4.4 [list.ops], paragraph 20 to:
    
 
-
    [
-Jens:  I plead for "NAD" on the grounds that "size of state" is only
-used as an argument for big-O complexity notation, thus
-constant factors and additions don't count.
-]
    
+
    
+"Throws: Nothing unless an exception is thrown by *(i-1) == *i or
+pred(*(i-1), *i)."
    
+
+
    
+Comments to the new wording:
    
+
+
    
+a) The wording regarding the conditions is identical to proposed
+23.3.4.4 [list.ops], paragraph 19. If 23.3.4.4 [list.ops],
+paragraph 19 is resolved in another way, the proposed wording need also
+additional review.
+b) The expression "(i - 1)" was left, but is expected that DR submitted
+by Thomas Mang regarding invalid iterator arithmetic expressions will
+take this into account.
+c) Typos fixed.
    
+
+
    
+Change 23.3.4.4 [list.ops], paragraph 21 to:
    
+
+
    
+"Complexity: If empty() == false, exactly size() - 1 applications of the
+corresponding predicate, otherwise no applications of the corresponding
+predicate."
    
+
+
    
+Comments to the new wording:
    
+
+
    
+a) The new wording is supposed to also replace the proposed resolution
+of DR 315, which suffers from the problem of undefined "first" / "last".
+
    
+
+
    
+5) References to other DRs:
    
+
+
    See DR 202.
+See DR 239.
+See DR 315.
+See DR submitted by Thomas Mang regarding invalid iterator arithmetic
+expressions.
    
 
 
-
    [
-Berlin: N1932 adopts the proposed NAD.
-]
    
+
+
    Proposed resolution:
    
 
 
+
    Rationale:
    
+
    "All implementations known to the author of this Defect Report
+comply with these assumption", and "no impact on current code is
+expected", i.e. there is no evidence of real-world confusion or
+harm.
    
 
 
 
 
 
 
    
-
    515. Random number engine traits
    
-
    Section: 26.5.1 [rand.synopsis], TR1 5.1.2 [tr.rand.synopsis] Status: NAD
- Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
-
    View all other issues in [rand.synopsis].
    
+
    492. Invalid iterator arithmetic expressions
    
+
    Section: 17.5.1.4 [structure.specifications] Status: NAD
+ Submitter: Thomas Mang Opened: 2004-12-12  Last modified: 2009-07-15
    
+
    View all other issues in [structure.specifications].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
+
    Various clauses other than clause 25 make use of iterator arithmetic not
+supported by the iterator category in question.
+Algorithms in clause 25 are exceptional because of 25 [lib.algorithms],
+paragraph 9, but this paragraph does not provide semantics to the
+expression "iterator - n", where n denotes a value of a distance type
+between iterators.
    
+
+
    1) Examples of current wording:
    
+
+
    Current wording outside clause 25:
    
+
 
    
-To accompany the concept of a pseudo-random number engine as defined in Table 17,
-we propose and recommend an adjunct template, engine_traits, to be declared in
-[tr.rand.synopsis] as:
+23.2.2.4 [lib.list.ops], paragraphs 19-21: "first + 1", "(i - 1)",
+"(last - first)"
+23.3.1.1 [lib.map.cons], paragraph 4: "last - first"
+23.3.2.1 [lib.multimap.cons], paragraph 4: "last - first"
+23.3.3.1 [lib.set.cons], paragraph 4: "last - first"
+23.3.4.1 [lib.multiset.cons], paragraph 4: "last - first"
+24.4.1 [lib.reverse.iterators], paragraph 1: "(i - 1)"
 
    
-
    template< class PSRE >
-class engine_traits;
-
    
+
 
    
-This template's primary purpose would be as an aid to generic programming involving
-pseudo-random number engines.  Given only the facilities described in tr1, it would
-be very difficult to produce any algorithms involving the notion of a generic engine.
-The intent of this proposal is to  provide, via engine_traits<>, sufficient
-descriptive information to allow an algorithm to employ a pseudo-random number engine
-without regard to its exact type, i.e., as a template parameter.
-
    
+[Important note: The list is not complete, just an illustration. The
+same issue might well apply to other paragraphs not listed here.]
    
+
+
    None of these expressions is valid for the corresponding iterator
+category.
    
+
+
    Current wording in clause 25:
    
+
 
    
-For example, today it is not possible to write an efficient generic function that
-requires any specific number of random bits.  More specifically, consider a
-cryptographic application that internally needs 256 bits of randomness per call:
+25.1.1 [lib.alg.foreach], paragraph 1: "last - 1"
+25.1.3 [lib.alg.find.end], paragraph 2: "[first1, last1 -
+(last2-first2))"
+25.2.8 [lib.alg.unique], paragraph 1: "(i - 1)"
+25.2.8 [lib.alg.unique], paragraph 5: "(i - 1)"
 
    
-
    template< class Eng, class InIter, class OutIter >
-void crypto( Eng& e, InIter in, OutIter out );
-
    
+
 
    
-Without knowning the number of bits of randomness produced per call to a provided
-engine, the algorithm has no means of determining how many times to call the engine.
-
    
+However, current wording of 25 [lib.algorithms], paragraph 9 covers
+neither of these four cases:
    
+
+
    Current wording of 25 [lib.algorithms], paragraph 9:
    
+
 
    
-In a new section [tr.rand.eng.traits], we proposed to define the engine_traits
-template as: 
-
    
-
    template< class PSRE >
-class engine_traits
-{
-  static  std::size_t  bits_of_randomness = 0u;
-  static  std::string  name()  { return "unknown_engine"; }
-  // TODO: other traits here
-};
-
    
+"In the description of the algorithms operator + and - are used for some
+of the iterator categories for which they do not have to be defined. In
+these cases the semantics of a+n is the same as that of
    
+
    {X tmp = a;
+advance(tmp, n);
+return tmp;
+}
+
    
+
    and that of b-a is the same as of return distance(a, b)"
    
+
 
    
-Further, each engine described in [tr.rand.engine] would be accompanied by a
-complete specialization of this new engine_traits template.
+This paragrpah does not take the expression "iterator - n" into account,
+where n denotes a value of a distance type between two iterators [Note:
+According to current wording, the expression "iterator - n" would be
+resolved as equivalent to "return distance(n, iterator)"]. Even if the
+expression "iterator - n" were to be reinterpreted as equivalent to
+"iterator + -n" [Note: This would imply that "a" and "b" were
+interpreted implicitly as values of iterator types, and "n" as value of
+a distance type], then 24.3.4/2 interfers because it says: "Requires: n
+may be negative only for random access and bidirectional iterators.",
+and none of the paragraphs quoted above requires the iterators on which
+the algorithms operate to be of random access or bidirectional category.
 
    
 
+
    2) Description of intended behavior:
    
 
+
    
+For the rest of this Defect Report, it is assumed that the expression
+"iterator1 + n" and "iterator1 - iterator2" has the semantics as
+described in current 25 [lib.algorithms], paragraph 9, but applying to
+all clauses. The expression "iterator1 - n" is equivalent to an
+result-iterator for which the expression "result-iterator + n" yields an
+iterator denoting the same position as iterator1 does. The terms
+"iterator1", "iterator2" and "result-iterator" shall denote the value of
+an iterator type, and the term "n" shall denote a value of a distance
+type between two iterators.
    
 
-
    Proposed resolution:
    
-
    [
-Berlin:  Walter: While useful for implementation per TR1, N1932 has no need for this
-feature.  Recommend close as NAD.
-]
    
+
    
+All implementations known to the author of this Defect Report comply
+with these assumptions.
+No impact on current code is expected.
    
 
+
    3) Proposed fixes:
    
 
 
-
    Rationale:
    
+
    Change 25 [lib.algorithms], paragraph 9 to:
    
+
 
    
-Recommend NAD,
-N1932,
-N2111
-covers this.  Already in WP.
+"In the description of the algorithms operator + and - are used for some
+of the iterator categories for which they do not have to be defined. In
+this paragraph, a and b denote values of an iterator type, and n denotes
+a value of a distance type between two iterators. In these cases the
+semantics of a+n is the same as that of
    
+
    {X tmp = a;
+advance(tmp, n);
+return tmp;
+}
+
    
+
    ,the semantics of a-n denotes the value of an iterator i for which the
+following condition holds:
+advance(i, n) == a,
+and that of b-a is the same as of
+return distance(a, b)".
 
    
 
+
    Comments to the new wording:
    
 
-
-
-
-
    
-
    516. Seeding subtract_with_carry_01 using a generator
    
-
    Section: 26.5.3 [rand.eng], TR1 5.1.4.4 [tr.rand.eng.sub1] Status: NAD Editorial
- Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
-
    View all other issues in [rand.eng].
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
 
    
-Paragraph 6 says:
+a) The wording " In this paragraph, a and b denote values of an iterator
+type, and n denotes a value of a distance type between two iterators."
+was added so the expressions "b-a" and "a-n" are distinguished regarding
+the types of the values on which they operate.
+b) The wording ",the semantics of a-n denotes the value of an iterator i
+for which the following condition holds: advance(i, n) == a" was added
+to cover the expression 'iterator - n'. The wording "advance(i, n) == a"
+was used to avoid a dependency on the semantics of a+n, as the wording
+"i + n == a" would have implied. However, such a dependency might well
+be deserved.
+c) DR 225 is not considered in the new wording.
 
    
-
    
-... obtained by successive invocations of g, ... 
-
    
+
 
    
-We recommend instead:
-
    
-
    
-... obtained by taking successive invocations of g mod 2**32, ...
-
    
+Proposed fixes regarding invalid iterator arithmetic expressions outside
+clause 25:
    
+
 
    
-as the context seems to require only 32-bit quantities be used here.
+Either
+a) Move modified 25 [lib.algorithms], paragraph 9 (as proposed above)
+before any current invalid iterator arithmetic expression. In that case,
+the first sentence of 25 [lib.algorithms], paragraph 9, need also to be
+modified and could read: "For the rest of this International Standard,
+...." / "In the description of the following clauses including this
+...." / "In the description of the text below ..." etc. - anyways
+substituting the wording "algorithms", which is a straight reference to
+clause 25.
+In that case, 25 [lib.algorithms] paragraph 9 will certainly become
+obsolete.
+Alternatively,
+b) Add an appropiate paragraph similar to resolved 25 [lib.algorithms],
+paragraph 9, to the beginning of each clause containing invalid iterator
+arithmetic expressions.
+Alternatively,
+c) Fix each paragraph (both current wording and possible resolutions of
+DRs) containing invalid iterator arithmetic expressions separately.
 
    
 
+
    5) References to other DRs:
    
 
-
    Proposed resolution:
    
 
    
-Berlin: N1932 adopts the proposed resultion: see 26.3.3.4/7.  Moved to Ready.
+See DR 225.
+See DR 237. The resolution could then also read "Linear in last -
+first".
 
    
 
 
    [
-Portland:  Subsumed by N2111.
+Bellevue:
 ]
    
 
 
+
    
+Keep open and ask Bill to provide wording.
+
    
+
+
    [
+2009-05-09 Alisdair adds:
+]
    
+
 
+
    
+This issue is related to 997.
+
    
 
+
    [
+2009-07 Frankfurt
+]
    
 
 
-
    
-
    517. Should include name in external representation
    
-
    Section: X [rand.req], TR1 5.1.1 [tr.rand.req] Status: NAD
- Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
-
    View all other issues in [rand.req].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
+
    
 
    
-The last two rows of Table 16 deal with the i/o requirements of an engine,
-specifying that the textual representation of an engine's state,
-appropriately formatted, constitute the engine's  external representation.
+Hinnant: this isn't going to change any user's code or any vendor's implementation.
 
    
 
    
-This seems adequate when an engine's type is known.  However, it seems
-inadequate in the  context of generic code, where it becomes useful and
-perhaps even necessary to determine an engine's type via input.
+No objection to "NAD without prejudice." If anyone proposes a
+resolution, the LWG will consider it.
 
    
 
    
+Move to NAD.
 
    
+
    
+
 
 
 
    Proposed resolution:
    
-
    
-We therefore recommend that, in each of these two rows of Table 16, the
-text "textual representation" be expanded so as to read "engine name
-followed by the textual representation."
-
    
 
-
    [
-Berlin: N1932 considers this NAD. This is a QOI issue.
-]
    
+
    [Lillehammer: Minor issue, but real. We have a blanket statement
+about this in 25/11. But (a) it should be in 17, not 25; and (b) it's
+not quite broad enough, because there are some arithmetic expressions
+it doesn't cover. Bill will provide wording.]
    
 
 
 
@@ -8400,556 +9817,723 @@ Berlin: N1932 considers this NAD. This is a QOI issue.
 
 
 
    
-
    525. type traits definitions not clear
    
-
    Section: 20.6.4 [meta.unary], TR1 4.5 [tr.meta.unary] Status: NAD Editorial
- Submitter: Robert Klarer Opened: 2005-07-11  Last modified: 2008-03-13
    
-
    View all issues with NAD Editorial status.
    
+
    493. Undefined Expression in Input Iterator Note Title
    
+
    Section: 24.2.2 [input.iterators] Status: NAD
+ Submitter: Chris Jefferson Opened: 2004-12-13  Last modified: 2006-12-27
    
+
    View all other issues in [input.iterators].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
-
    
-It is not completely clear how the primary type traits deal with
-cv-qualified types.  And several of the secondary type traits
-seem to be lacking a definition.
-
    
+
    1) In 24.1.1/3, the following text is currently present.
    
 
-
    [
-Berlin:  Howard to provide wording.
-]
    
+
    "Note: For input iterators, a==b does not imply ++a=++b (Equality does
+not guarantee the substitution property or referential transparency)."
    
+
+
    However, when in Table 72, part of the definition of ++r is given as:
    
+
+
    "pre: r is dereferenceable.
+post: any copies of the previous value of r are no longer required
+either to be dereferenceable ..."
    
 
+
    While a==b does not imply that b is a copy of a, this statement should
+perhaps still be made more clear.
    
 
+
    2) There are no changes to intended behaviour
    
 
-
    Proposed resolution:
    
 
    
-Wording provided in N2028.
-A
-revision (N2157)
-provides more detail for motivation.
-
    
+3) This Note should be altered to say "Note: For input iterators a==b,
+when its behaviour is defined ++a==++b may still be false (Equality does
+not guarantee the substitution property or referential transparency).
    
+
+
+
+
    Proposed resolution:
    
 
 
 
    Rationale:
    
-Solved by revision (N2157)
-in the WP.
+
    This is descriptive text, not normative, and the meaning is clear.
    
 
 
 
 
 
 
    
-
    526. Is it undefined if a function in the standard changes in parameters?
    
-
    Section: 23.2.3 [sequence.reqmts] Status: NAD
- Submitter: Chris Jefferson Opened: 2005-09-14  Last modified: 2008-03-13
    
-
    View other active issues in [sequence.reqmts].
    
-
    View all other issues in [sequence.reqmts].
    
+
    494. Wrong runtime complexity for associative container's insert and delete
    
+
    Section: 23.2.4 [associative.reqmts] Status: NAD
+ Submitter: Hans B os Opened: 2004-12-19  Last modified: 2006-12-27
    
+
    View all other issues in [associative.reqmts].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
-
    
-Problem: There are a number of places in the C++ standard library where
-it is possible to write what appear to be sensible ways of calling
-functions, but which can cause problems in some (or all)
-implementations, as they cause the values given to the function to be
-changed in a way not specified in standard (and therefore not coded to
-correctly work). These fall into two similar categories.
-
    
+
    According to [lib.associative.reqmts] table 69, the runtime comlexity
+of insert(p, t) and erase(q) can be done in amortized constant time.
    
+
+
    It was my understanding that an associative container could be
+implemented as a balanced binary tree.
    
+
+
    For inser(p, t), you 'll have to iterate to p's next node to see if t
+can be placed next to p.  Furthermore, the insertion usually takes
+place at leaf nodes. An insert next to the root node will be done at
+the left of the root next node
    
+
+
    So when p is the root node you 'll have to iterate from the root to
+its next node, which  takes O(log(size)) time in a balanced tree.
    
+
+
    If you insert all values with insert(root, t) (where root is the
+root of the tree before insertion) then each insert takes O(log(size))
+time.  The amortized complexity per insertion will be O(log(size))
+also.
    
+
+
    For erase(q), the normal algorithm for deleting a node that has no
+empty left or right subtree, is to iterate to the next (or previous),
+which is a leaf node. Then exchange the node with the next and delete
+the leaf node.  Furthermore according to DR 130, erase should return
+the next node of the node erased.  Thus erasing the root node,
+requires iterating to the next node.
    
+
+
    Now if you empty a map by deleting the root node until the map is
+empty, each operation will take O(log(size)), and the amortized
+complexity is still O(log(size)).
    
+
+
    The operations can be done in amortized constant time if iterating
+to the next node can be done in (non amortized) constant time.  This
+can be done by putting all nodes in a double linked list.  This
+requires two extra links per node.  To me this is a bit overkill since
+you can already efficiently insert or erase ranges with erase(first,
+last) and insert(first, last).
    
+
+
+
+
    Proposed resolution:
    
+
+
+
    Rationale:
    
+
    Only "amortized constant" in special circumstances, and we believe
+  that's implementable. That is: doing this N times will be O(N), not
+  O(log N).
    
+
+
+
+
+
+
    
+
    499. Std. doesn't seem to require stable_sort() to be stable!
    
+
    Section: 25.5.1.2 [stable.sort] Status: NAD Editorial
+ Submitter: Prateek Karandikar Opened: 2005-04-12  Last modified: 2008-03-13
    
+
    View all issues with NAD Editorial status.
    
+
    Discussion:
    
+
    
+17.3.1.1 Summary
    
 
 
    
-1) Parameters taken by const reference can be changed during execution
-of the function
+1 The Summary provides a synopsis of the category, and introduces the 
+first-level subclauses. Each subclause also provides a summary, listing 
+the headers specified in the subclause and the library entities 
+provided in each header. 
 
    
-
 
    
-Examples:
+2 Paragraphs labelled "Note(s):" or "Example(s):" are informative, 
+other paragraphs are normative.
+
     
+
+
    So this means that a "Notes" paragraph wouldn't be normative. 
    
+
+
    
+25.3.1.2 stable_sort
 
    
+
    template<class RandomAccessIterator> 
+void stable_sort(RandomAccessIterat or first, RandomAccessIterator last); 
 
+template<class RandomAccessIterator, class Compare> 
+void stable_sort(RandomAccessIterat or first, RandomAccessIterator last, Compare comp);
+
    
 
    
-Given std::vector<int> v:
+1 Effects: Sorts the elements in the range [first, last).
 
    
 
    
-v.insert(v.begin(), v[2]);
+2 Complexity: It does at most N(log N)^2 (where N == last - first) 
+comparisons; if enough extra memory is available, it is N log N.
 
    
 
    
-v[2] can be changed by moving elements of vector
-
    
-
+3 Notes: Stable: the relative order of the equivalent elements is 
+preserved. 
+
     
 
 
    
-Given std::list<int> l:
+The Notes para is informative, and nowhere else is stability mentioned above. 
 
    
+
 
    
-l.remove(*l.begin());
+Also, I just searched for the word "stable" in my copy of the Standard. 
+and the phrase "Notes: Stable: the relative order of the elements..." 
+is repeated several times in the Standard library clauses for 
+describing various functions. How is it that stability is talked about 
+in the informative paragraph? Or am I missing something obvious? 
 
    
+
+
+
    Proposed resolution:
    
 
    
-Will delete the first element, and then continue trying to access it.
-This is particularily vicious, as it will appear to work in almost all
-cases.
 
    
 
+
+
    Rationale:
    
 
    
-2) A range is given which changes during the execution of the function:
-Similarly,
+This change has already been made.
 
    
 
+
+
+
+
+
    
+
    500. do_length cannot be implemented correctly
    
+
    Section: 22.4.1.5 [locale.codecvt.byname] Status: NAD
+ Submitter: Krzysztof Żelechowski Opened: 2005-05-24  Last modified: 2008-03-13
    
+
    View all other issues in [locale.codecvt.byname].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
      
+
    1. codecvt::do_length is of type int;
      2. 
+
    2. it is assumed to be sort-of returning from_next - from of type ptrdiff_t;
      3. 
+
    3. ptrdiff_t cannot be cast to an int without data loss.
      4. 
+
    
 
    
-v.insert(v.begin(), v.begin()+4, v.begin()+6);
+Contradiction.
 
    
 
+
+
    Proposed resolution:
    
 
    
-This kind of problem has been partly covered in some cases. For example
-std::copy(first, last, result) states that result cannot be in the range
-[first, last). However, does this cover the case where result is a
-reverse_iterator built from some iterator in the range [first, last)?
-Also, std::copy would still break if result was reverse_iterator(last +
-1), yet this is not forbidden by the standard
 
    
 
+
+
+
+
+
    
+
    501. Proposal: strengthen guarantees of lib.comparisons
    
+
    Section: 20.7.3 [base] Status: NAD
+ Submitter: Me <anti_spam_email2003@yahoo.com> Opened: 2005-06-07  Last modified: 2008-03-13
    
+
    View all other issues in [base].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    
+"For templates greater, less, greater_equal, and less_equal,
+the specializations for any pointer type yield a total order, even if
+the built-in operators <, >, <=, >= do not."
+
    
+
 
    
-Solution:
+The standard should do much better than guarantee that these provide a
+total order, it should guarantee that it can be used to test if memory
+overlaps, i.e. write a portable memmove. You can imagine a platform
+where the built-in operators use a uint32_t comparison (this tests for
+overlap on this platform) but the less<T*> functor is allowed to be
+defined to use a int32_t comparison. On this platform, if you use
+std::less with the intent of making a portable memmove, comparison on
+an array that straddles the 0x7FFFFFFF/0x8000000 boundary can give
+incorrect results.
 
    
 
+
+
    Proposed resolution:
    
 
    
-One option would be to try to more carefully limit the requirements of
-each function. There are many functions which would have to be checked.
-However as has been shown in the std::copy case, this may be difficult.
-A simpler, more global option would be to somewhere insert text similar to:
+Add a footnote to 20.5.3/8 saying:
 
    
 
+
    
+Given a p1 and p2 such that p1 points to N objects of type T and p2
+points to M objects of type T. If [p1,p1+N) does not overlap [p2,p2+M),
+less returns the same value when comparing all pointers in [p1,p1+N) to
+all pointers in [p2,p2+M). Otherwise, there is a value Q and a value R
+such that less returns the same value when comparing all pointers in
+[p1,p1+Q) to all pointers in [p2,p2+R) and an opposite value when
+comparing all pointers in [p1+Q,p1+N) to all pointers in [p2+R,p2+M).
+For the sake of completeness, the null pointer value (4.10) for T is
+considered to be an array of 1 object that doesn't overlap with any
+non-null pointer to T. less_equal, greater, greater_equal, equal_to,
+and not_equal_to give the expected results based on the total ordering
+semantics of less. For T of void, treat it as having similar semantics
+as T of char i.e. less<cv T*>(a, b) gives the same results as less<cv
+void*>(a, b) which gives the same results as less<cv char*>((cv
+char*)(cv void*)a, (cv char*)(cv void*)b).
+
    
+
 
    
-If the execution of any function would change either any values passed
-by reference or any value in any range passed to a function in a way not
-defined in the definition of that function, the result is undefined.
+I'm also thinking there should be a footnote to 20.5.3/1 saying that if
+A and B are similar types (4.4/4), comp<A>(a,b) returns the same value
+as comp<B>(a,b) (where comp is less, less_equal, etc.). But this might
+be problematic if there is some really funky operator overloading going
+on that does different things based on cv (that should be undefined
+behavior if somebody does that though). This at least should be
+guaranteed for all POD types (especially pointers) that use the
+built-in comparison operators.
 
    
 
+
+
+
    Rationale:
    
 
    
-Such code would have to at least cover chapters 23 and 25 (the sections
-I read through carefully). I can see no harm on applying it to much of
-the rest of the standard.
+less is already required to provide a strict weak ordering which is good enough
+to detect overlapping memory situations.
 
    
 
+
+
+
+
+
    
+
    502. Proposition: Clarification of the interaction between a facet and an iterator
    
+
    Section: 22.3.1.1.1 [locale.category] Status: NAD
+ Submitter: Christopher Conrade Zseleghovski Opened: 2005-06-07  Last modified: 2009-07-15
    
+
    View all other issues in [locale.category].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
    
-Some existing parts of the standard could be improved to fit with this,
-for example the requires for 25.2.1 (Copy) could be adjusted to:
+Motivation:
 
    
 
 
    
-Requires: For each non-negative integer n < (last - first), assigning to
-*(result + n) must not alter any value in the range [first + n, last).
+This requirement seems obvious to me, it is the essence of code modularity. 
+I have complained to Mr. Plauger that the Dinkumware library does not 
+observe this principle but he objected that this behaviour is not covered in 
+the standard.
 
    
 
+
    [
+2009-07 Frankfurt
+]
    
+
+
+
    
 
    
-However, this may add excessive complication.
+No objection to NAD, Fixed.
+
    
+
    
+Move to NAD.
 
    
+
    
 
+
+
+
    Proposed resolution:
    
 
    
-One other benefit of clearly introducing this text is that it would
-allow a number of small optimisations, such as caching values passed
-by const reference.
+Append the following point to 22.1.1.1.1:
 
    
 
 
    
-Matt Austern adds that this issue also exists for the insert and
-erase members of the ordered and unordered associative containers.
+6. The implementation of a facet of Table 52 parametrized with an 
+InputIterator/OutputIterator should use that iterator only as character 
+source/sink respectively.
+For a *_get facet, it means that the value received depends only on the 
+sequence of input characters and not on how they are accessed.
+For a *_put facet, it means that the sequence of characters output depends 
+only on the value to be formatted and not of how the characters are stored.
 
    
 
 
    [
-Berlin: Lots of controversey over how this should be solved. Lots of confusion
-as to whether we're talking about self referencing iterators or references.
-Needs a good survey as to the cases where this matters, for which
-implementations, and how expensive it is to fix each case.
+Berlin:  Moved to Open, Need to clean up this area to make it clear
+locales don't have to contain open ended sets of facets. Jack, Howard,
+Bill.
 ]
    
 
 
 
 
-
    Proposed resolution:
    
 
 
-
    Rationale:
    
+
+
    
+
    503. more on locales
    
+
    Section: 22.4 [locale.categories] Status: NAD
+ Submitter: P.J. Plauger Opened: 2005-06-20  Last modified: 2009-07-15
    
+
    View all other issues in [locale.categories].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
    
-Recommend NAD.
+a) In 22.2.1.1 para. 2 we refer to "the instantiations required in Table
+51" to refer to the facet *objects* associated with a locale. And we
+almost certainly mean just those associated with the default or "C"
+locale. Otherwise, you can't switch to a locale that enforces a different
+mapping between narrow and wide characters, or that defines additional
+uppercase characters.
 
    
-
      
-
    • vector::insert(iter, value) is required to work because the standard
-doesn't give permission for it not to work.
      • 
-
    • list::remove(value) is required to work because the standard
-doesn't give permission for it not to work.
      • 
-
    • vector::insert(iter, iter, iter) is not required to work because
-23.2.3 [sequence.reqmts], p4 says so.
      • 
-
    • copy has to work, except where 25.4.1 [alg.copy] says
-it doesn't have to work.  While a language lawyer can tear this wording apart,
-it is felt that the wording is not prone to accidental interpretation.
      • 
-
    • The current working draft provide exceptions for the unordered associative
-containers similar to the containers requirements which exempt the member
-template insert functions from self referencing.
      • 
-
    
-
 
+
    
+b) 22.2.1.5 para. 3 (codecvt) has the same issues.
+
    
 
+
    
+c) 22.2.1.5.2 (do_unshift) is even worse. It *forbids* the generation of
+a homing sequence for the basic character set, which might very well need
+one.
+
    
 
+
    
+d) 22.2.1.5.2 (do_length) likewise dictates that the default mapping
+between wide and narrow characters be taken as one-for-one.
+
    
 
-
    
-
    528. const_iterator iterator issue when they are the same type
    
-
    Section: 23.5 [unord], TR1 6.3.4 [tr.unord.unord] Status: NAD
- Submitter: Paolo Carlini Opened: 2005-10-12  Last modified: 2008-03-13
    
-
    View all other issues in [unord].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
 
    
-while implementing the resolution of issue 6.19 I'm noticing the
-following: according to 6.3.4.3/2 (and 6.3.4.5/2), for unordered_set and
-unordered_multiset:
+e) 22.2.2 para. 2 (num_get/put) is both muddled and vacuous, as far as
+I can tell. The muddle is, as before, calling Table 51 a list of
+instantiations. But the constraint it applies seems to me to cover
+*all* defined uses of num_get/put, so why bother to say so?
 
    
 
-
    
-    "The iterator and const_iterator types are both const types. It is
-unspecified whether they are the same type"
-
    
+
    
+f) 22.2.3.1.2 para. 1(do_decimal_point) says "The required instantiations
+return '.' or L'.'.) Presumably this means "as appropriate for the
+character type. But given the vague definition of "required" earlier,
+this overrules *any* change of decimal point for non "C" locales.
+Surely we don't want to do that.
+
    
 
 
    
-Now, according to the resolution of 6.19, we have overloads of insert
-with hint and erase (single and range) both for iterator and
-const_iterator, which, AFAICS, can be meaningful at the same time *only*
-if iterator and const_iterator *are* in fact different types.
+g) 22.2.3.1.2 para. 2 (do_thousands_sep) says "The required instantiations
+return ',' or L','.) As above, this probably means "as appropriate for the
+character type. But this overrules the "C" locale, which requires *no*
+character ('\0') for the thousands separator. Even if we agree that we
+don't mean to block changes in decimal point or thousands separator,
+we should also eliminate this clear incompatibility with C.
 
    
+
 
    
-Then, iterator and const_iterator are *required* to be different types?
-Or that is an unintended consequence? Maybe the overloads for plain
-iterators should be added only to unordered_map and unordered_multimap?
-Or, of course, I'm missing something?
+h) 22.2.3.1.2 para. 2 (do_grouping) says "The required instantiations
+return the empty string, indicating no grouping." Same considerations
+as for do_decimal_point.
 
    
 
+
    
+i) 22.2.4.1 para. 1 (collate) refers to "instantiations required in Table
+51". Same bad jargon.
+
    
 
+
    
+j) 22.2.4.1.2 para. 1 (do_compare) refers to "instantiations required
+in Table 51". Same bad jargon.
+
    
 
-
    Proposed resolution:
    
 
    
-Add to 6.3.4.3p2 (and 6.3.4.5p2):
+k) 22.2.5 para. 1 (time_get/put) uses the same muddled and vacuous
+as num_get/put.
 
    
+
 
    
-2  ... The iterator and const_iterator types are both const
-constant iterator types.
-It is unspecified whether they are the same type. 
+l) 22.2.6 para. 2 (money_get/put) uses the same muddled and vacuous
+as num_get/put.
 
    
 
 
    
-Add a new subsection to 17.4.4 [lib.conforming]:
+m) 22.2.6.3.2 (do_pos/neg_format) says "The instantiations required
+in Table 51 ... return an object of type pattern initialized to
+{symbol, sign, none, value}." This once again *overrides* the "C"
+locale, as well as any other locale."
 
    
 
-
    
 
    
-An implementation shall not supply an overloaded function
-       signature specified in any library clause if such a signature
-       would be inherently ambiguous during overload resolution
-       due to two library types referring to the same type.
+3) We constrain the use_facet calls that can be made by num_get/put,
+so why don't we do the same for money_get/put? Or for any of the
+other facets, for that matter?
 
    
+
 
    
-       [Note: For example, this occurs when a container's iterator
-       and const_iterator types are the same. -- end note]
+4) As an almost aside, we spell out when a facet needs to use the ctype
+facet, but several also need to use a codecvt facet and we don't say so.
 
    
-
    
+
    [
+Berlin: Bill to provide wording.
+]
    
+
 
 
    [
-Post-Berlin: Beman supplied wording.
+2009-07 Frankfurt
 ]
    
 
 
+
    
+
    
+No objection to NAD.
+
    
+
    
+Move to NAD.
+
    
+
    
+
 
 
-
    Rationale:
    
-Toronto:  The first issue has been fixed by N2350 (the insert and erase members
-are collapsed into one signature).  Alisdair to open a separate issue on the
-chapter 17 wording.
+
    Proposed resolution:
    
+
    
+
    
 
 
 
 
 
 
    
-
    529. The standard encourages redundant and confusing preconditions
    
-
    Section: 17.6.3.11 [res.on.required] Status: NAD Editorial
- Submitter: David Abrahams Opened: 2005-10-25  Last modified: 2008-03-13
    
+
    504. Integer types in pseudo-random number engine requirements
    
+
    Section: X [rand.req], TR1 5.1.1 [tr.rand.req] Status: NAD Editorial
+ Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
+
    View all other issues in [rand.req].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-17.4.3.8/1 says:
+In [tr.rand.req], Paragraph 2 states that "... s is a value of integral type,
+g is an ... object returning values of unsigned integral type ..."
 
    
 
-
    
-Violation of the preconditions specified in a function's 
-Required behavior: paragraph results in undefined behavior unless the 
-function's Throws: paragraph specifies throwing an exception when the 
-precondition is violated.
-
    
 
+
    Proposed resolution:
    
 
    
-This implies that a precondition violation can lead to defined
-behavior.  That conflicts with the only reasonable definition of
-precondition: that a violation leads to undefined behavior.  Any other
-definition muddies the waters when it comes to analyzing program
-correctness, because precondition violations may be routinely done in
-correct code (e.g. you can use std::vector::at with the full
-expectation that you'll get an exception when your index is out of
-range, catch the exception, and continue).  Not only is it a bad
-example to set, but it encourages needless complication and redundancy
-in the standard.  For example:
+In 5.1.1 [tr.rand.req], Paragraph 2 replace
 
    
 
-
      21 Strings library 
-  21.3.3 basic_string capacity
-
-  void resize(size_type n, charT c);
-
-  5 Requires: n <= max_size()
-  6 Throws: length_error if n > max_size().
-  7 Effects: Alters the length of the string designated by *this as follows:
-
    
+
    
+... s is a value of integral type, g is an lvalue of a type other than X that
+defines a zero-argument function object returning values of unsigned integral type
+unsigned long int,
+...
+
    
 
 
    
-The Requires clause is entirely redundant and can be dropped.  We
-could make that simplifying change (and many others like it) even
-without changing 17.4.3.8/1; the wording there just seems to encourage
-the redundant and error-prone Requires: clause.
+In 5.1.1 [tr.rand.seq], Table 16, replace in the line for X(s)
 
    
 
+
    
+creates an engine with the initial internal state
+determined by static_cast<unsigned long>(s)
+
    
+
 
    [
-Batavia:  Alan and Pete to work.
+Mont Tremblant:  Both s and g should be unsigned long.
+This should refer to the constructor signatures. Jens  provided wording post Mont Tremblant.
 ]
    
 
 
 
    [
-Bellevue:  NAD Editorial, this group likes 
-N2121,
-Pete agrees, accepting it is Pete's business.
-General agreement that precondition violations are synonymous with UB.
+Berlin:  N1932 adopts the proposed resolution:  see 26.3.1.3/1e and Table 3 row 2. Moved
+to Ready.
 ]
    
 
 
 
-
    Proposed resolution:
    
-
    
-1. Change 17.4.3.8/1 to read:
-
    
-
-
    
-Violation of the preconditions specified in a function's
-Required behavior: paragraph results in undefined behavior
-unless the function's Throws: paragraph specifies throwing
-an exception when the precondition is violated.
-
    
 
+
    Rationale:
    
 
    
-2. Go through and remove redundant Requires: clauses.  Specifics to be
-   provided by Dave A.
+Jens:  Just requiring X(unsigned long) still makes it possible
+for an evil library writer to also supply a X(int) that does something
+unexpected.  The wording above requires that X(s) always performs
+as if X(unsigned long) would have been called.  I believe that is
+sufficient and implements our intentions from Mont Tremblant.  I
+see no additional use in actually requiring a X(unsigned long)
+signature.  u.seed(s) is covered by its reference to X(s), same
+arguments.
 
    
 
-
    [
-Berlin: The LWG requests a detailed survey of part 2 of the proposed resolution.
-]
    
-
 
 
    [
-Alan provided the survey
-N2121.
+Portland:  Subsumed by N2111.
 ]
    
 
 
 
 
 
-
-
 
    
-
    532. Tuple comparison
    
-
    Section: 20.5.2.5 [tuple.rel], TR1 6.1.3.5 [tr.tuple.rel] Status: NAD Editorial
- Submitter: David Abrahams Opened: 2005-11-29  Last modified: 2008-09-23
    
-
    View all other issues in [tuple.rel].
    
-
    View all issues with NAD Editorial status.
    
-
    Duplicate of: 348
    
+
    506. Requirements of Distribution parameter for variate_generator
    
+
    Section: 26.5 [rand], TR1 5.1.3 [tr.rand.var] Status: NAD
+ Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
+
    View all other issues in [rand].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-Where possible, tuple comparison operators <,<=,=>, and > ought to be
-defined in terms of std::less rather than operator<, in order to
-support comparison of tuples of pointers.  
+Paragraph 3 requires that template argument U (which corresponds to template
+parameter Engine) satisfy all uniform random number generator requirements.
+However, there is no  analogous requirement regarding the template argument
+that corresponds to template parameter Distribution.  We believe there should
+be, and that it should require that this template argument satisfy all random
+distribution requirements.
 
    
 
 
 
    Proposed resolution:
    
 
    
-change 6.1.3.5/5 from:
+Consequence 1: Remove the precondition clauses [tr.rand.var]/16 and /18.
 
    
-
-
    
-  Returns: The result of a lexicographical comparison between t and
-  u. The result is defined as: (bool)(get<0>(t) < get<0>(u)) ||
-  (!(bool)(get<0>(u) < get<0>(t)) && ttail < utail), where rtail for
-  some tuple r is a tuple containing all but the first element of
-  r. For any two zero-length tuples e and f, e < f returns false.
-
    
-
 
    
-to:
+Consequence 2: Add max() and min() functions to those distributions that
+do not already have them.
 
    
 
-
    
-
    
-  Returns: The result of a lexicographical comparison between t and
-  u. For any two zero-length tuples e and f, e < f returns false.
-  Otherwise, the result is defined as: cmp( get<0>(t), get<0>(u)) ||
-  (!cmp(get<0>(u), get<0>(t)) && ttail < utail), where rtail for some
-  tuple r is a tuple containing all but the first element of r, and
-  cmp(x,y) is an unspecified function template defined as follows.
-
    
-
    
-  Where T is the type of x and U is the type of y:
-
    
+
    [
+Mont Tremblant: Jens reccommends NAD, min/max not needed everywhere.
+Marc supports having min and max to satisfy generic programming interface.
+]
    
 
-
    
-     if T and U are pointer types and T is convertible to U, returns
-     less<U>()(x,y)
-
    
 
-
    
-     otherwise, if T and U are pointer types, returns less<T>()(x,y)
-
    
 
-
    
-     otherwise, returns (bool)(x < y)
-
    
-
    
 
-
    [
-Berlin: This issue is much bigger than just tuple (pair, containers,
-algorithms). Dietmar will survey and work up proposed wording.
-]
    
+
    Rationale:
    
+
    Berlin:  N1932 makes this moot: variate_generator has been eliminated.
    
 
 
 
 
-
    Rationale:
    
+
+
    
+
    509. Uniform_int template parameters
    
+
    Section: 26.5.8.1 [rand.dist.uni], TR1 5.1.7.1 [tr.rand.dist.iunif] Status: NAD
+ Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
+
    View all other issues in [rand.dist.uni].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    
+In [tr.rand.dist.iunif] the uniform_int distribution currently has a single
+template parameter, IntType, used as the input_type and as the result_type
+of the distribution.  We believe there is no reason to conflate these types
+in this way.
+
    
+
+
+
    Proposed resolution:
    
 
    
-Recommend NAD.  This will be fixed with the next revision of concepts.
+We recommend that there be a second template  parameter to
+reflect the distribution's input_type, and that the existing first template
+parameter continue to reflect (solely) the result_type:
 
    
+
    template< class IntType = int, UIntType = unsigned int >
+class uniform_int
+{
+public:
+  // types
+  typedef  UIntType  input_type;
+  typedef  IntType   result_type;
+
    
 
 
    [
-San Francisco:
+Berlin: Moved to NAD.  N1932 makes this moot: the input_type template parameter has been
+eliminated.
 ]
    
 
 
-
    
-Solved by
-N2770.
-
    
 
 
 
 
 
 
    
-
    536. Container iterator constructor and explicit convertibility
    
-
    Section: 23.2 [container.requirements] Status: Dup
- Submitter: Joaquín M López Muñoz Opened: 2005-12-17  Last modified: 2007-04-18
    
-
    View other active issues in [container.requirements].
    
-
    View all other issues in [container.requirements].
    
-
    View all issues with Dup status.
    
-
    Duplicate of: 589
    
+
    510. Input_type for bernoulli_distribution
    
+
    Section: 26.5.8.2 [rand.dist.bern], TR1 5.1.7.2 [tr.rand.dist.bern] Status: NAD
+ Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-The iterator constructor X(i,j) for containers as defined in 23.1.1 and
-23.2.2 does only require that i and j be input iterators but
-nothing is said about their associated value_type. There are three
-sensible
-options:
-
    
-
      
-
    1. iterator's value_type is exactly X::value_type (modulo cv).
      2. 
-
    2. iterator's value_type is *implicitly* convertible to X::value_type.
      3. 
-
    3. iterator's value_type is *explicitly* convertible to X::value_type.
      4. 
-
    
-
    
-The issue has practical implications, and stdlib vendors have
-taken divergent approaches to it: Dinkumware follows 2,
-libstdc++ follows 3.
-
    
-
    
-The same problem applies to the definition of insert(p,i,j) for
-sequences and insert(i,j) for associative contianers, as well as
-assign.
+In [tr.rand.dist.bern] the distribution currently requires;
 
    
+
    typedef  int  input_type;
+
    
 
-
    [
-The following added by Howard and the example code was originally written by
-Dietmar.
-]
    
 
+
    Proposed resolution:
    
 
    
-Valid code below?
+We believe this is an unfortunate choice, and recommend instead:
 
    
-
-
    #include <vector> 
-#include <iterator> 
-#include <iostream> 
-
-struct foo 
-{ 
-    explicit foo(int) {} 
-}; 
-
-int main() 
-{ 
-    std::vector<int> v_int; 
-    std::vector<foo> v_foo1(v_int.begin(), v_int.end()); 
-    std::vector<foo> v_foo2((std::istream_iterator<int>(std::cin)), 
-                             std::istream_iterator<int>()); 
-} 
+
    typedef  unsigned int  input_type;
 
    
+
 
    [
-Berlin: Some support, not universal, for respecting the explicit qualifier.
+Berlin:  Moved to NAD. N1932 makes this moot: the input_type template parameter has been
+eliminated.
 ]
    
 
 
 
 
-
    Proposed resolution:
    
-
-
-
 
 
 
 
    
-
    544. minor NULL problems in C.2
    
-
    Section: C.2 [diff.library] Status: NAD Editorial
- Submitter: Martin Sebor Opened: 2005-11-25  Last modified: 2007-04-24
    
-
    View all other issues in [diff.library].
    
-
    View all issues with NAD Editorial status.
    
+
    511. Input_type for binomial_distribution
    
+
    Section: 26.5.8 [rand.dist], TR1 5.1.7.5 [tr.rand.dist.bin] Status: NAD
+ Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
+
    View all other issues in [rand.dist].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-According to C.2.2.3, p1, "the macro NULL, defined in any of <clocale>,
-<cstddef>, <cstdio>, <cstdlib>, <cstring>, <ctime>,
-or <cwchar>." This is consistent with the C standard.
+Unlike all other distributions in TR1, this binomial_distribution has an
+implementation-defined  input_type.  We believe this is an unfortunate choice,
+because it hinders users from writing portable code.  It also hinders the
+writing of compliance tests.  We recommend instead:
 
    
+
    typedef  RealType  input_type;
+
    
 
    
-However, Table 95 in C.2 fails to mention <clocale> and <cstdlib>.
+While this choice is somewhat arbitrary (as it was for some of the other
+distributions), we make  this particular choice because (unlike all other
+distributions) otherwise this template would not publish its RealType
+argument and so users could not write generic code that accessed this
+second template parameter.  In this respect, the choice is consistent with
+the other distributions in  TR1. 
 
    
 
    
-In addition, C.2, p2 claims that "The C++ Standard library provides
-54 standard macros from the C library, as shown in Table 95." While
-table 95 does have 54 entries, since a couple of them (including the
-NULL macro) are listed more than once, the actual number of macros
-defined by the C++ Standard Library may not be 54.
+We have two reasons for recommending that a real type be specified instead.
+One reason is  based specifically on characteristics of binomial distribution
+implementations, while the other is based on mathematical characteristics of
+probability distribution functions in general.
+
    
+
    
+Implementations of binomial distributions commonly use Stirling approximations
+for values in certain ranges.  It is far more natural to use real values to
+represent these approximations than it would be to use integral values to do
+so.  In other ranges, implementations reply on the Bernoulli  distribution to
+obtain values.  While TR1's bernoulli_distribution::input_type is specified as
+int, we believe this would be better specified as double.
+
    
+
    
+This brings us to our main point:  The notion of a random distribution rests
+on the notion of a cumulative distribution function, which in turn mathematically
+depends on a continuous dependent variable.  Indeed, such a distribution function
+would be meaningless if it depended on  discrete values such as integers - and this
+remains true even if the distribution function were to take discrete steps.
+
    
+
    
+Although this note is specifically about binomial_distribution::input_type,
+we intend to recommend that all of the random distributions input_types be
+specified as a real type (either a RealType template parameter, or double,
+as appropriate).
+
    
+
    
+Of the nine distributions in TR1, four already have this characteristic
+(uniform_real, exponential_distribution, normal_distribution, and
+gamma_distribution).  We have already argued the case for the binomial the
+remaining four distributions.
+
    
+
    
+In the case of uniform_int, we believe that the calculations to produce an
+integer result in a  specified range from an integer in a different specified
+range is best done using real arithmetic.  This is because it involves a
+product, one of whose terms is the ratio of the extents of the two ranges.
+Without real arithmetic, the results become less uniform: some numbers become
+more  (or less) probable that they should be.  This is, of course, undesireable
+behavior in a uniform distribution.
+
    
+
    
+Finally, we believe that in the case of the bernoulli_distribution (briefly
+mentioned earlier), as well as the cases of the geometric_distribution and the
+poisson_distribution, it would be far more natural to have a real input_type.
+This is because the most natural computation involves the  random number
+delivered and the distribution's parameter p (in the case of bernoulli_distribution,
+for example, the computation is a comparison against p), and p is already specified
+in each case as having some real type.
 
    
 
 
 
    Proposed resolution:
    
-
    
-I propose we add <clocale> and <cstdlib> to Table 96 and remove the
-number of macros from C.2, p2 and reword the sentence as follows:
-
    
-
    
-The C++ Standard library provides 54 standard macros from
-defines a number macros corresponding to those defined by the C 
-Standard library, as shown in Table 96.
-
    
+
    typedef  RealType  input_type;
+
    
 
 
    [
-Portland:  Resolution is considered editorial.  It will be incorporated into the WD.
+Berlin:  Moved to NAD.  N1932 makes this moot: the input_type template parameter has been
+eliminated.
 ]
    
 
 
@@ -8957,106 +10541,141 @@ Portland:  Resolution is considered editorial.  It will be incorporated into the
 
 
 
-
 
    
-
    547. division should be floating-point, not integer
    
-
    Section: 26.5 [rand], TR1 5.1 [tr.rand] Status: NAD
- Submitter: Matt Austern Opened: 2006-01-10  Last modified: 2007-04-18
    
-
    View other active issues in [rand].
    
-
    View all other issues in [rand].
    
-
    View all issues with NAD status.
    
+
    512. Seeding subtract_with_carry_01 from a single unsigned long
    
+
    Section: 26.5.3 [rand.eng], TR1 5.1.4.4 [tr.rand.eng.sub1] Status: NAD Editorial
+ Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
+
    View all other issues in [rand.eng].
    
+
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-Paragraph 10 describes how a variate generator uses numbers produced by an
-engine to pass to a generator. The sentence that concerns me is: "Otherwise, if
-the value for engine_value_type::result_type is true and the value for
-Distribution::input_type is false [i.e. if the engine produces integers and the
-engine wants floating-point values], then the numbers in s_eng are divided by
-engine().max() - engine().min() + 1 to obtain the numbers in s_e." Since the
-engine is producing integers, both the numerator and the denominator are
-integers and we'll be doing integer division, which I don't think is what we
-want. Shouldn't we be performing a conversion to a floating-point type first?
+Paragraph 8 specifies the algorithm by which a subtract_with_carry_01  engine
+is to be seeded given a single unsigned long.  This algorithm is seriously
+flawed in the case where the engine parameter w (also known as word_size)
+exceeds 31 [bits].  The key part of the paragraph reads:
+
    
+
    
+sets x(-r) ... x(-1) to (lcg(1)*2**(-w)) mod 1
+
    
+
    
+and so forth. 
+
    
+
    
+Since the specified linear congruential engine, lcg, delivers numbers with
+a maximum of 2147483563 (just a shade under 31 bits), then when w is, for
+example, 48, each of the x(i) will be less than 2**-17.  The consequence
+is that roughly the first 400 numbers delivered will be  conspicuously
+close to either zero or one.
+
    
+
    
+Unfortunately, this is not an innocuous flaw:  One of the predefined engines
+in [tr.rand.predef],  namely ranlux64_base_01, has w = 48 and would exhibit
+this poor behavior, while the original N1378 proposal states that these
+pre-defined engines are intended to be of "known good properties."
 
    
 
 
 
    Proposed resolution:
    
-
-
-
    Rationale:
    
 
    
-Recommend NAD as the affected section is now gone and so the issue is moot.
-N2111.
+In 5.1.4.4 [tr.rand.eng.sub1], replace the "effects" clause for
+void seed(unsigned long value = 19780503) by
 
    
 
+
    
+Effects: If value == 0, sets value to 19780503. In any
+case, with a linear congruential generator lcg(i) having parameters
+mlcg = 2147483563, alcg = 40014,
+clcg = 0, and lcg(0) = value,
+sets carry(-1) and x(-r) … x(-1)
+as if executing
    
 
+
    
+linear_congruential<unsigned long, 40014, 0, 2147483563> lcg(value);
+seed(lcg);
+
    
 
+
    
+to (lcg(1) · 2-w) mod 1
+… (lcg(r) · 2-w) mod 1,
+respectively. If x(-1) == 0, sets carry(-1) = 2-w,
+else sets carry(-1) = 0.
    
+
    
 
+
    [
+Jens provided revised wording post Mont Tremblant.
+]
    
 
-
    
-
    548. May random_device block?
    
-
    Section: 26.5.6 [rand.device], TR1 5.1.6 [tr.rand.device] Status: NAD
- Submitter: Matt Austern Opened: 2006-01-10  Last modified: 2007-10-18
    
-
    View all other issues in [rand.device].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
-
    
-Class random_device "produces non-deterministic random numbers", using some
-external source of entropy. In most real-world systems, the amount of available
-entropy is limited. Suppose that entropy has been exhausted. What is an
-implementation permitted to do? In particular, is it permitted to block
-indefinitely until more random bits are available, or is the implementation
-required to detect failure immediately? This is not an academic question. On
-Linux a straightforward implementation would read from /dev/random, and "When
-the entropy pool is empty, reads to /dev/random will block until additional
-environmental noise is gathered." Programmers need to know whether random_device
-is permitted to (or possibly even required to?) behave the same way.
-
    
 
 
    [
-Berlin: Walter: N1932 considers this NAD. Does the standard specify whether std::cin
-may block?
+Berlin: N1932 adopts the originally-proposed resolution of the issue.
+Jens's supplied wording is a clearer description of what is
+intended.  Moved to Ready.
 ]
    
 
 
-
    
-See N2391 and
-N2423
-for some further discussion.
-
    
 
 
-
    Proposed resolution:
    
+
    Rationale:
    
 
    
-Adopt the proposed resolution in
-N2423 (NAD).
+Jens: I'm using an explicit type here, because fixing the
+prose would probably not qualify for the (with issue 504 even
+stricter) requirements we have for seed(Gen&).
 
    
 
+
    [
+Portland:  Subsumed by N2111.
+]
    
+
+
+
 
 
 
-
 
    
-
    549. Undefined variable in binomial_distribution
    
-
    Section: 26.5.8 [rand.dist], TR1 5.1.7.5 [tr.rand.dist.bin] Status: NAD Editorial
- Submitter: Matt Austern Opened: 2006-01-10  Last modified: 2007-04-24
    
-
    View all other issues in [rand.dist].
    
+
    513. Size of state for subtract_with_carry_01
    
+
    Section: 26.5.3 [rand.eng], TR1 5.1.4.4 [tr.rand.eng.sub1] Status: NAD Editorial
+ Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
+
    View all other issues in [rand.eng].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-Paragraph 1 says that "A binomial distributon random distribution produces
-integer values i>0 with p(i) = (n choose i) * p*i * (1-p)^(t-i), where t and
-p are the parameters of the distribution. OK, that tells us what t, p, and i
-are. What's n?
+Paragraph 3 begins:
+
    
+
    
+The size of the state is r.
+
    
+
    
+However, this is not quite consistent with the remainder of the paragraph
+which specifies a total  of nr+1 items in the textual representation of
+the state.  We recommend the sentence be corrected to match:
+
    
+
    
+The size of the state is nr+1.
+
    
+
    
+To give meaning to the coefficient n, it may be also desirable to move
+n's definition from later in the paragraph.  Either of the following
+seem reasonable formulations:
 
    
+
    
+With n=..., the size of the state is nr+1.
+
    
+
    
+The size of the state is nr+1, where n=... .
+
    
+
 
 
 
    Proposed resolution:
    
-
    
-Berlin: Typo: "n" replaced by "t" in N1932: see 26.3.7.2.2/1.
-
    
+
    [
+Jens:  I plead for "NAD" on the grounds that "size of state" is only
+used as an argument for big-O complexity notation, thus
+constant factors and additions don't count.
+]
    
+
 
 
    [
-Portland:  Subsumed by N2111.
+Berlin: N1932 adopts the proposed NAD.
 ]
    
 
 
@@ -9064,133 +10683,157 @@ Portland:  Subsumed by N2111.
 
 
 
+
 
    
-
    553. very minor editorial change intptr_t / uintptr_t
    
-
    Section: 18.4.1 [cstdint.syn], TR1 8.22.1 [tr.c99.cstdint.syn] Status: NAD Editorial
- Submitter: Paolo Carlini Opened: 2006-01-30  Last modified: 2007-07-02
    
-
    View all other issues in [cstdint.syn].
    
+
    514. Size of state for subtract_with_carry
    
+
    Section: 26.5.3.3 [rand.eng.sub], TR1 5.1.4.3 [tr.rand.eng.sub] Status: NAD Editorial
+ Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-In the synopsis, some types are identified as optional: int8_t, int16_t,
-and so on, consistently with C99, indeed.
+Paragraph 2 begins:
 
    
+
    
+The size of the state is r.
+
    
 
    
-On the other hand, intptr_t and uintptr_t, are not marked as such and
-probably should, consistently with C99, 7.18.1.4.
+However, the next sentence specifies a total of r+1 items in the textual
+representation of the state,  r specific x's as well as a specific carry.
+This makes a total of r+1 items that constitute the size of the state,
+rather than r.
 
    
 
 
 
    Proposed resolution:
    
 
    
-Change 18.4.1 [cstdint.syn]:
+We recommend the sentence be corrected to match:
 
    
+
    
+ The size of the state is r+1.
+
    
+
+
    [
+Jens:  I plead for "NAD" on the grounds that "size of state" is only
+used as an argument for big-O complexity notation, thus
+constant factors and additions don't count.
+]
    
 
-
    ...
-typedef signed integer type intptr_t;    // optional
-...
-typedef unsigned integer type uintptr_t;    // optional
-...
-
    
 
+
    [
+Berlin: N1932 adopts the proposed NAD.
+]
    
 
 
-
    Rationale:
    
-Recommend NAD and fix as editorial with the proposed resolution.
 
 
 
 
 
 
    
-
    554. Problem with lwg DR 184 numeric_limits<bool>
    
-
    Section: 18.3.1.5 [numeric.special] Status: NAD
- Submitter: Howard Hinnant Opened: 2006-01-29  Last modified: 2007-01-15
    
-
    View all other issues in [numeric.special].
    
+
    515. Random number engine traits
    
+
    Section: 26.5.1 [rand.synopsis], TR1 5.1.2 [tr.rand.synopsis] Status: NAD
+ Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
+
    View all other issues in [rand.synopsis].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-I believe we have a bug in the resolution of:
-lwg 184
-(WP status).
+To accompany the concept of a pseudo-random number engine as defined in Table 17,
+we propose and recommend an adjunct template, engine_traits, to be declared in
+[tr.rand.synopsis] as:
 
    
-
+
    template< class PSRE >
+class engine_traits;
+
    
 
    
-The resolution spells out each member of numeric_limits<bool>.
-The part I'm having a little trouble with is:
+This template's primary purpose would be as an aid to generic programming involving
+pseudo-random number engines.  Given only the facilities described in tr1, it would
+be very difficult to produce any algorithms involving the notion of a generic engine.
+The intent of this proposal is to  provide, via engine_traits<>, sufficient
+descriptive information to allow an algorithm to employ a pseudo-random number engine
+without regard to its exact type, i.e., as a template parameter.
 
    
-
    static const bool traps = false;
+
    
+For example, today it is not possible to write an efficient generic function that
+requires any specific number of random bits.  More specifically, consider a
+cryptographic application that internally needs 256 bits of randomness per call:
+
    
+
    template< class Eng, class InIter, class OutIter >
+void crypto( Eng& e, InIter in, OutIter out );
 
    
-
 
    
-Should this not be implementation defined?  Given:
+Without knowning the number of bits of randomness produced per call to a provided
+engine, the algorithm has no means of determining how many times to call the engine.
 
    
-
-
    int main()
+
    
+In a new section [tr.rand.eng.traits], we proposed to define the engine_traits
+template as: 
+
    
+
    template< class PSRE >
+class engine_traits
 {
-     bool b1 = true;
-     bool b2 = false;
-     bool b3 = b1/b2;
-}
+  static  std::size_t  bits_of_randomness = 0u;
+  static  std::string  name()  { return "unknown_engine"; }
+  // TODO: other traits here
+};
 
    
-
 
    
-If this causes a trap, shouldn't numeric_limits<bool>::traps be
-true?
+Further, each engine described in [tr.rand.engine] would be accompanied by a
+complete specialization of this new engine_traits template.
 
    
 
 
-
    Proposed resolution:
    
-
    
-Change 18.2.1.5p3:
-
    
-
-
    
--3- The specialization for bool shall be provided as follows: 
    
-
    namespace std { 
-   template <> class numeric_limits<bool> {
-      ...
-      static const bool traps = false implementation-defined;
-      ...
-   };
-}
-
    
-
    
 
+
    Proposed resolution:
    
 
    [
-Redmond:  NAD because traps refers to values, not operations.  There is no bool
-value that will trap.
+Berlin:  Walter: While useful for implementation per TR1, N1932 has no need for this
+feature.  Recommend close as NAD.
 ]
    
 
 
 
+
    Rationale:
    
+
    
+Recommend NAD,
+N1932,
+N2111
+covers this.  Already in WP.
+
    
+
 
 
 
 
 
    
-
    555. TR1, 8.21/1: typo
    
-
    Section: TR1 8.21 [tr.c99.boolh] Status: NAD Editorial
- Submitter: Paolo Carlini Opened: 2006-02-02  Last modified: 2007-04-24
    
+
    516. Seeding subtract_with_carry_01 using a generator
    
+
    Section: 26.5.3 [rand.eng], TR1 5.1.4.4 [tr.rand.eng.sub1] Status: NAD Editorial
+ Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
+
    View all other issues in [rand.eng].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-This one, if nobody noticed it yet, seems really editorial:
-s/cstbool/cstdbool/
+Paragraph 6 says:
+
    
+
    
+... obtained by successive invocations of g, ... 
+
    
+
    
+We recommend instead:
+
    
+
    
+... obtained by taking successive invocations of g mod 2**32, ...
+
    
+
    
+as the context seems to require only 32-bit quantities be used here.
 
    
 
 
 
    Proposed resolution:
    
 
    
-Change 8.21p1:
+Berlin: N1932 adopts the proposed resultion: see 26.3.3.4/7.  Moved to Ready.
 
    
-
    
--1- The header behaves as if it defines the additional macro defined in
-<cstdbool> by including the header <cstdbool>.
-
    
 
 
    [
-Redmond:  Editorial.
+Portland:  Subsumed by N2111.
 ]
    
 
 
@@ -9198,621 +10841,618 @@ Redmond:  Editorial.
 
 
 
-
 
    
-
    556. is Compare a BinaryPredicate?
    
-
    Section: 25.5 [alg.sorting] Status: NAD Editorial
- Submitter: Martin Sebor Opened: 2006-02-05  Last modified: 2008-09-26
    
-
    View all other issues in [alg.sorting].
    
-
    View all issues with NAD Editorial status.
    
+
    517. Should include name in external representation
    
+
    Section: X [rand.req], TR1 5.1.1 [tr.rand.req] Status: NAD
+ Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-03-13
    
+
    View all other issues in [rand.req].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-In 25, p8 we allow BinaryPredicates to return a type that's convertible
-to bool but need not actually be bool. That allows predicates to return
-things like proxies and requires that implementations be careful about
-what kinds of expressions they use the result of the predicate in (e.g.,
-the expression in if (!pred(a, b)) need not be well-formed since the
-negation operator may be inaccessible or return a type that's not
-convertible to bool).
+The last two rows of Table 16 deal with the i/o requirements of an engine,
+specifying that the textual representation of an engine's state,
+appropriately formatted, constitute the engine's  external representation.
 
    
 
    
-Here's the text for reference:
+This seems adequate when an engine's type is known.  However, it seems
+inadequate in the  context of generic code, where it becomes useful and
+perhaps even necessary to determine an engine's type via input.
 
    
-
    
-  ...if an algorithm takes BinaryPredicate binary_pred as its argument
- and first1 and first2 as its iterator arguments, it should work
- correctly in the construct if (binary_pred(*first1, first2)){...}.
-
    
-
 
    
-In 25.3, p2 we require that the Compare function object return true
-of false, which would seem to preclude such proxies. The relevant text
-is here:
 
    
-
    
-  Compare is used as a function object which returns true if the first
-  argument is less than the second, and false otherwise...
-
    
-
 
 
 
    Proposed resolution:
    
 
    
-I think we could fix this by rewording 25.3, p2 to read somthing like:
+We therefore recommend that, in each of these two rows of Table 16, the
+text "textual representation" be expanded so as to read "engine name
+followed by the textual representation."
 
    
-
    
--2- Compare is used as a function object which returns
-true if the first argument a BinaryPredicate. The
-return value of the function call operator applied to an object of type
-Compare, when converted to type bool, yields true
-if the first argument of the call is less than the second, and
-false otherwise. Compare comp is used throughout for
-algorithms assuming an ordering relation. It is assumed that comp
-will not apply any non-constant function through the dereferenced iterator.
-
    
-
-
-
    [
-Portland:  Jack to define "convertible to bool" such that short circuiting isn't
-destroyed.
-]
    
 
-
-
    Rationale:
    
 
    [
-San Francisco:
+Berlin: N1932 considers this NAD. This is a QOI issue.
 ]
    
 
 
-
    
-Solved by
-(N2774).
-
    
-
 
 
 
 
 
 
    
-
    557. TR1: div(_Longlong, _Longlong) vs div(intmax_t, intmax_t)
    
-
    Section: 18.4 [cstdint], TR1 8.22 [tr.c99.cstdint] Status: NAD Editorial
- Submitter: Paolo Carlini Opened: 2006-02-06  Last modified: 2008-07-02
    
-
    View all other issues in [cstdint].
    
-
    View all issues with NAD Editorial status.
    
+
    523. regex case-insensitive character ranges are unimplementable as specified
    
+
    Section: 28 [re] Status: NAD Future
+ Submitter: Eric Niebler Opened: 2005-07-01  Last modified: 2009-07-15
    
+
    View all other issues in [re].
    
+
    View all issues with NAD Future status.
    
 
    Discussion:
    
 
    
-I'm seeing a problem with such overloads: when, _Longlong == intmax_t ==
-long long we end up, essentially, with the same arguments and different
-return types (lldiv_t and imaxdiv_t, respectively). Similar issue with
-abs(_Longlong) and abs(intmax_t), of course.
+A problem with TR1 regex is currently being discussed on the Boost 
+developers list. It involves the handling of case-insensitive matching 
+of character ranges such as [Z-a]. The proper behavior (according to the 
+ECMAScript standard) is unimplementable given the current specification 
+of the TR1 regex_traits<> class template. John Maddock, the author of 
+the TR1 regex proposal, agrees there is a problem. The full discussion 
+can be found at http://lists.boost.org/boost/2005/06/28850.php (first 
+message copied below). We don't have any recommendations as yet.
 
    
 
    
-Comparing sections 8.25 and 8.11, I see an important difference,
-however: 8.25.3 and 8.25.4 carefully describe div and abs for _Longlong
-types (rightfully, because not moved over directly from C99), whereas
-there is no equivalent in 8.11: the abs and div overloads for intmax_t
-types appear only in the synopsis and are not described anywhere, in
-particular no mention in 8.11.2 (at variance with 8.25.2).
+-- Begin original message --
 
    
 
    
-I'm wondering whether we really, really, want div and abs for intmax_t...
+The situation of interest is described in the ECMAScript specification
+(ECMA-262), section 15.10.2.15:
+
    
+
    
+"Even if the pattern ignores case, the case of the two ends of a range
+is significant in determining which characters belong to the range.
+Thus, for example, the pattern /[E-F]/i matches only the letters E, F,
+e, and f, while the pattern /[E-f]/i matches all upper and lower-case
+ASCII letters as well as the symbols [, \, ], ^, _, and `."
+
    
+
    
+A more interesting case is what should happen when doing a
+case-insentitive match on a range such as [Z-a]. It should match z, Z,
+a, A and the symbols [, \, ], ^, _, and `. This is not what happens with
+Boost.Regex (it throws an exception from the regex constructor).
+
    
+
    
+The tough pill to swallow is that, given the specification in TR1, I
+don't think there is any effective way to handle this situation.
+According to the spec, case-insensitivity is handled with
+regex_traits<>::translate_nocase(CharT) -- two characters are equivalent
+if they compare equal after both are sent through the translate_nocase
+function. But I don't see any way of using this translation function to
+make character ranges case-insensitive. Consider the difficulty of
+detecting whether "z" is in the range [Z-a]. Applying the transformation
+to "z" has no effect (it is essentially std::tolower). And we're not
+allowed to apply the transformation to the ends of the range, because as
+ECMA-262 says, "the case of the two ends of a range is significant."
+
    
+
    
+So AFAICT, TR1 regex is just broken, as is Boost.Regex. One possible fix
+is to redefine translate_nocase to return a string_type containing all
+the characters that should compare equal to the specified character. But
+this function is hard to implement for Unicode, and it doesn't play nice
+with the existing ctype facet. What a mess!
+
    
+
    
+-- End original message --
 
    
-
-
-
-
    Proposed resolution:
    
-
-
-
-
    [
-Portland: no consensus.
-]
    
-
-
-
    Rationale:
    
-
    [
-Batavia, Bill: The <cstdint> synopsis in TR1 8.11.1 [tr.c99.cinttypes.syn] contains:
-]
    
-
-
    intmax_t imaxabs(intmax_t i);
-intmax_t abs(intmax_t i);
-
-imaxdiv_t imaxdiv(intmax_t numer, intmax_t denom);
-imaxdiv_t div(intmax_t numer, intmax_t denom);
-
    
 
 
    [
-and in TR1 8.11.2 [tr.c99.cinttypes.def]:
+John Maddock adds:
 ]
    
 
 
-
    
-The header defines all functions, types, and macros the same as C99
-subclause 7.8.
-
    
+
    
+One small correction, I have since found that ICU's regex package does 
+implement this correctly, using a similar mechanism to the current 
+TR1.Regex.
+
    
+
    
+Given an expression [c1-c2] that is compiled as case insensitive it:
+
    
+
    
+Enumerates every character in the range c1 to c2 and converts it to it's 
+case folded equivalent.  That case folded character is then used a key to a 
+table of equivalence classes, and each member of the class is added to the 
+list of possible matches supported by the character-class.  This second step 
+isn't possible with our current traits class design, but isn't necessary if 
+the input text is also converted to a case-folded equivalent on the fly.
+
    
+
    
+ICU applies similar brute force mechanisms to character classes such as 
+[[:lower:]] and [[:word:]], however these are at least cached, so the impact 
+is less noticeable in this case.
+
    
+
    
+Quick and dirty performance comparisons show that expressions such as 
+"[X-\\x{fff0}]+" are indeed very slow to compile with ICU (about 200 times 
+slower than a "normal" expression).  For an application that uses a lot of 
+regexes this could have a noticeable performance impact.  ICU also has an 
+advantage in that it knows the range of valid characters codes: code points 
+outside that range are assumed not to require enumeration, as they can not 
+be part of any equivalence class.  I presume that if we want the TR1.Regex 
+to work with arbitrarily large character sets enumeration really does become 
+impractical.
+
    
+
    
+Finally note that Unicode has:
+
    
+
    
+Three cases (upper, lower and title).
+One to many, and many to one case transformations.
+Character that have context sensitive case translations - for example an 
+uppercase sigma has two different lowercase forms  - the form chosen depends 
+on context(is it end of a word or not), a caseless match for an upper case 
+sigma should match either of the lower case forms, which is why case folding 
+is often approximated by tolower(toupper(c)).
+
    
+
    
+Probably we need some way to enumerate character equivalence classes, 
+including digraphs (either as a result or an input), and some way to tell 
+whether the next character pair is a valid digraph in the current locale.
+
    
+
    
+Hoping this doesn't make this even more complex that it was already,
+
    
 
 
    [
-This is as much definition as we give for most other C99 functions,
-so nothing need change. We might, however, choose to add the footnote:
+Portland:  Alisdair: Detect as invalid, throw an exception.
+Pete: Possible general problem with case insensitive ranges.
 ]
    
 
 
-
    
-[Note: These overloads for abs and div may well be equivalent to
-those that take long long arguments. If so, the implementation is
-responsible for avoiding conflicting declarations. -- end note]
-
    
-
 
    [
-Bellevue: NAD Editorial. Pete must add a footnote, as described below.
+2009-07 Frankfurt
 ]
    
 
 
 
    
-
    [
-Looks like a real problem. Dietmar suggests div() return a template
-type. Matt: looks like imaxdiv_t is loosly defined. Can it be a typedef
-for lldiv_t when _Longlong == intmax_t? PJP seems to agree. We would
-need a non-normative note declaring that the types lldiv_t and imaxdiv_t
-may not be unique if intmax_t==_longlong.
-]
    
-
+
    
+We agree that this is a problem, but we do not know the answer.
+
    
+
    
+We are going to declare this NAD until existing practice leads us in some direction.
+
    
+
    
+No objection to NAD Future.
+
    
+
    
+Move to NAD Future.
+
    
 
    
 
 
 
+
    Proposed resolution:
    
+
+
 
 
 
 
    
-
    558. lib.input.iterators Defect
    
-
    Section: 24.2.2 [input.iterators] Status: NAD Editorial
- Submitter: David Abrahams Opened: 2006-02-09  Last modified: 2007-04-24
    
-
    View all other issues in [input.iterators].
    
+
    525. type traits definitions not clear
    
+
    Section: 20.6.4 [meta.unary], TR1 4.5 [tr.meta.unary] Status: NAD Editorial
+ Submitter: Robert Klarer Opened: 2005-07-11  Last modified: 2008-03-13
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
-
    
-
    
-  24.1.1 Input iterators [lib.input.iterators]
-
    
 
    
-  1 A class or a built-in type X satisfies the requirements of an
-  input iterator for the value type T if the following expressions are
-  valid, where U is the type of any specified member of type T, as
-  shown in Table 73.
-
    
-
    
-
    
-There is no capital U used in table 73.  There is a lowercase u, but
-that is clearly not meant to denote a member of type T.  Also, there's
-no description in 24.1.1 of what lowercase a means.  IMO the above
-should have been...Hah, a and b are already covered in 24.1/11, so maybe it
-should have just been:
+It is not completely clear how the primary type traits deal with
+cv-qualified types.  And several of the secondary type traits
+seem to be lacking a definition.
 
    
 
+
    [
+Berlin:  Howard to provide wording.
+]
    
+
+
 
 
    Proposed resolution:
    
 
    
-Change 24.1.1p1:
+Wording provided in N2028.
+A
+revision (N2157)
+provides more detail for motivation.
 
    
-
    
--1- A class or a built-in type X satisfies the requirements of an
-input iterator for the value type T if the following expressions 
-are valid, where U is the type of any specified member of type
-T, as shown in Table 73.
-
    
-
-
    [
-Portland: Editorial.
-]
    
 
 
+
    Rationale:
    
+Solved by revision (N2157)
+in the WP.
 
 
 
 
 
 
    
-
    560. User-defined allocators without default constructor
    
-
    Section: X [allocator.requirements] Status: NAD
- Submitter: Sergey P. Derevyago Opened: 2006-02-17  Last modified: 2007-04-18
    
-
    View other active issues in [allocator.requirements].
    
-
    View all other issues in [allocator.requirements].
    
+
    526. Is it undefined if a function in the standard changes in parameters?
    
+
    Section: 23.2.3 [sequence.reqmts] Status: NAD
+ Submitter: Chris Jefferson Opened: 2005-09-14  Last modified: 2008-03-13
    
+
    View all other issues in [sequence.reqmts].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
-
    1. The essence of the problem.
    
 
    
-User-defined allocators without default constructor are not explicitly
-supported by the standard but they can be supported just like std::vector
-supports elements without default constructor.
+Problem: There are a number of places in the C++ standard library where
+it is possible to write what appear to be sensible ways of calling
+functions, but which can cause problems in some (or all)
+implementations, as they cause the values given to the function to be
+changed in a way not specified in standard (and therefore not coded to
+correctly work). These fall into two similar categories.
 
    
+
 
    
-As a result, there exist implementations that work well with such allocators
-and implementations that don't.
+1) Parameters taken by const reference can be changed during execution
+of the function
 
    
 
-
    2. The cause of the problem.
    
 
    
-1) The standard doesn't explicitly state this intent but it should. In
-particular, 20.1.5p5 explicitly state the intent w.r.t. the allocator
-instances that compare non-equal. So it can similarly state the intent w.r.t.
-the user-defined allocators without default constructor.
+Examples:
 
    
+
 
    
-2) Some container operations are obviously underspecified. In particular,
-21.3.7.1p2 tells:
+Given std::vector<int> v:
 
    
-
    template<class charT, class traits, class Allocator>
-  basic_string<charT,traits,Allocator> operator+(
-    const charT* lhs,
-    const basic_string<charT,traits,Allocator>& rhs
-  );
-
    
 
    
-Returns: basic_string<charT,traits,Allocator>(lhs) + rhs.
+v.insert(v.begin(), v[2]);
 
    
-
    
 
    
-That leads to the basic_string<charT,traits,Allocator>(lhs, Allocator()) call.
-Obviously, the right requirement is:
+v[2] can be changed by moving elements of vector
 
    
-
    
-Returns: basic_string<charT,traits,Allocator>(lhs, rhs.get_allocator()) + rhs.
-
    
+
+
 
    
-It seems like a lot of DRs can be submitted on this "Absent call to
-get_allocator()" topic.
+Given std::list<int> l:
 
    
-
-
    3. Proposed actions.
    
 
    
-1) Explicitly state the intent to allow for user-defined allocators without
-default constructor in 20.1.5 Allocator requirements.
+l.remove(*l.begin());
 
    
 
    
-2) Correct all the places, where a correct allocator object is available
-through the get_allocator() call but default Allocator() gets passed instead.
+Will delete the first element, and then continue trying to access it.
+This is particularily vicious, as it will appear to work in almost all
+cases.
 
    
-
    4. Code sample.
    
+
 
    
-Let's suppose that the following memory pool is available:
+2) A range is given which changes during the execution of the function:
+Similarly,
 
    
-
    class mem_pool {
-      // ...
-      void* allocate(size_t size);
-      void deallocate(void* ptr, size_t size);
-};
-
    
+
 
    
-So the following allocator can be implemented via this pool:
+v.insert(v.begin(), v.begin()+4, v.begin()+6);
 
    
-
    class stl_allocator {
-      mem_pool& pool;
 
- public:
-      explicit stl_allocator(mem_pool& mp) : pool(mp) {}
-      stl_allocator(const stl_allocator& sa) : pool(sa.pool) {}
-      template <class U>
-      stl_allocator(const stl_allocator<U>& sa)  : pool(sa.get_pool()) {}
-      ~stl_allocator() {}
+
    
+This kind of problem has been partly covered in some cases. For example
+std::copy(first, last, result) states that result cannot be in the range
+[first, last). However, does this cover the case where result is a
+reverse_iterator built from some iterator in the range [first, last)?
+Also, std::copy would still break if result was reverse_iterator(last +
+1), yet this is not forbidden by the standard
+
    
 
-      pointer allocate(size_type n, std::allocator<void>::const_pointer = 0)
-      {
-       return (n!=0) ? static_cast<pointer>(pool.allocate(n*sizeof(T))) : 0;
-      }
+
    
+Solution:
+
    
 
-      void deallocate(pointer p, size_type n)
-      {
-       if (n!=0) pool.deallocate(p, n*sizeof(T));
-      }
+
    
+One option would be to try to more carefully limit the requirements of
+each function. There are many functions which would have to be checked.
+However as has been shown in the std::copy case, this may be difficult.
+A simpler, more global option would be to somewhere insert text similar to:
+
    
 
-      // ...
-};
-
    
 
    
-Then the following code works well on some implementations and doesn't work on
-another:
-
    
-
    typedef basic_string<char, char_traits<char>, stl_allocator<char> > 
-  tl_string;
-mem_pool mp;
-tl_string s1("abc", stl_allocator<int>(mp));
-printf("(%s)\n", ("def"+s1).c_str());
-
    
-
    
-In particular, on some implementations the code can't be compiled without
-default stl_allocator() constructor.
-
    
-
    
-The obvious way to solve the compile-time problems is to intentionally define
-a NULL pointer dereferencing default constructor
-
    
-
    stl_allocator() : pool(*static_cast<mem_pool*>(0)) {}
-
    
-
    
-in a hope that it will not be called. The problem is that it really gets
-called by operator+(const char*, const string&) under the current 21.3.7.1p2
-wording.
+If the execution of any function would change either any values passed
+by reference or any value in any range passed to a function in a way not
+defined in the definition of that function, the result is undefined.
 
    
 
-
-
    Proposed resolution:
    
 
    
+Such code would have to at least cover chapters 23 and 25 (the sections
+I read through carefully). I can see no harm on applying it to much of
+the rest of the standard.
 
    
 
-
-
    Rationale:
    
 
    
-Recommend NAD.  operator+() with string already requires the desired
-semantics of copying the allocator from one of the strings (lhs when there is a choice).
+Some existing parts of the standard could be improved to fit with this,
+for example the requires for 25.2.1 (Copy) could be adjusted to:
 
    
 
-
-
-
-
-
    
-
    569. Postcondition for basic_ios::clear(iostate) incorrectly stated
    
-
    Section: 27.5.4.3 [iostate.flags] Status: Dup
- Submitter: Seungbeom Kim Opened: 2006-03-10  Last modified: 2006-12-30
    
-
    View all other issues in [iostate.flags].
    
-
    View all issues with Dup status.
    
-
    Duplicate of: 272
    
-
    Discussion:
    
 
    
-Section: 27.4.4.3 [lib.iostate.flags]
+Requires: For each non-negative integer n < (last - first), assigning to
+*(result + n) must not alter any value in the range [first + n, last).
 
    
+
 
    
-Paragraph 4 says:
+However, this may add excessive complication.
 
    
-
    
-
    void clear(iostate state = goodbit);
-
    
+
 
    
-Postcondition: If rdbuf()!=0 then state == rdstate();
-otherwise rdstate()==state|ios_base::badbit.
+One other benefit of clearly introducing this text is that it would
+allow a number of small optimisations, such as caching values passed
+by const reference.
 
    
-
    
 
 
    
-The postcondition "rdstate()==state|ios_base::badbit" is parsed as
-"(rdstate()==state)|ios_base::badbit", which is probably what the
-committee meant.
+Matt Austern adds that this issue also exists for the insert and
+erase members of the ordered and unordered associative containers.
 
    
 
+
    [
+Berlin: Lots of controversey over how this should be solved. Lots of confusion
+as to whether we're talking about self referencing iterators or references.
+Needs a good survey as to the cases where this matters, for which
+implementations, and how expensive it is to fix each case.
+]
    
+
 
 
 
-
    Rationale:
    
+
    Proposed resolution:
    
+
 
+
    Rationale:
    
+
    
+Recommend NAD.
+
    
+
      
+
    • vector::insert(iter, value) is required to work because the standard
+doesn't give permission for it not to work.
      • 
+
    • list::remove(value) is required to work because the standard
+doesn't give permission for it not to work.
      • 
+
    • vector::insert(iter, iter, iter) is not required to work because
+23.2.3 [sequence.reqmts], p4 says so.
      • 
+
    • copy has to work, except where 25.4.1 [alg.copy] says
+it doesn't have to work.  While a language lawyer can tear this wording apart,
+it is felt that the wording is not prone to accidental interpretation.
      • 
+
    • The current working draft provide exceptions for the unordered associative
+containers similar to the containers requirements which exempt the member
+template insert functions from self referencing.
      • 
+
    
 
 
 
 
 
 
    
-
    570. Request adding additional explicit specializations of char_traits
    
-
    Section: 21.2 [char.traits] Status: NAD
- Submitter: Jack Reeves Opened: 2006-04-06  Last modified: 2008-06-18
    
-
    View all other issues in [char.traits].
    
+
    528. const_iterator iterator issue when they are the same type
    
+
    Section: 23.5 [unord], TR1 6.3.4 [tr.unord.unord] Status: NAD
+ Submitter: Paolo Carlini Opened: 2005-10-12  Last modified: 2008-03-13
    
+
    View all other issues in [unord].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-Currently, the Standard Library specifies only a declaration for template class
-char_traits<> and requires the implementation provide two explicit
-specializations: char_traits<char> and char_traits<wchar_t>. I feel the Standard
-should require explicit specializations for all built-in character types, i.e.
-char, wchar_t, unsigned char, and signed char.
+while implementing the resolution of issue 6.19 I'm noticing the
+following: according to 6.3.4.3/2 (and 6.3.4.5/2), for unordered_set and
+unordered_multiset:
 
    
+
+
    
+    "The iterator and const_iterator types are both const types. It is
+unspecified whether they are the same type"
+
    
+
 
    
-I have put together a paper
-(N1985)
-that describes this in more detail and
-includes all the necessary wording.
+Now, according to the resolution of 6.19, we have overloads of insert
+with hint and erase (single and range) both for iterator and
+const_iterator, which, AFAICS, can be meaningful at the same time *only*
+if iterator and const_iterator *are* in fact different types.
+
    
+
    
+Then, iterator and const_iterator are *required* to be different types?
+Or that is an unintended consequence? Maybe the overloads for plain
+iterators should be added only to unordered_map and unordered_multimap?
+Or, of course, I'm missing something?
 
    
-
    [
-Portland: Jack will rewrite
-N1985
-to propose a primary template that will work with other integral types.
-]
    
 
-
    [
-Toronto: issue has grown with addition of char16_t and char32_t.
-]
    
 
 
-
    [
-post Bellevue:
-]
    
+
    Proposed resolution:
    
+
    
+Add to 6.3.4.3p2 (and 6.3.4.5p2):
+
    
+
    
+2  ... The iterator and const_iterator types are both const
+constant iterator types.
+It is unspecified whether they are the same type. 
+
    
 
+
    
+Add a new subsection to 17.4.4 [lib.conforming]:
+
    
 
 
    
 
    
-We suggest that Jack be asked about the status of his paper, and if it
-is not forthcoming, the work-item be assigned to someone else. If no one
-steps forward to do the paper before the next meeting, we propose to
-make this NAD without further discussion. We leave this Open for now,
-but our recommendation is NAD.
+An implementation shall not supply an overloaded function
+       signature specified in any library clause if such a signature
+       would be inherently ambiguous during overload resolution
+       due to two library types referring to the same type.
 
    
 
    
-Note: the issue statement should be updated, as the Toronto comment has
-already been resolved. E.g., char_traits specializations for char16_t
-and char32_t are now in the working paper.
+       [Note: For example, this occurs when a container's iterator
+       and const_iterator types are the same. -- end note]
 
    
 
    
 
 
    [
-Sophia Antipolis:
+Post-Berlin: Beman supplied wording.
 ]
    
 
 
-
    
-Nobody has submitted the requested paper, so we move to NAD, as suggested by the decision at the last meeting.
-
    
 
 
-
    Proposed resolution:
    
+
    Rationale:
    
+Toronto:  The first issue has been fixed by N2350 (the insert and erase members
+are collapsed into one signature).  Alisdair to open a separate issue on the
+chapter 17 wording.
 
 
 
 
 
 
    
-
    571. Update C90 references to C99?
    
-
    Section: 1.2 [intro.refs] Status: NAD Editorial
- Submitter: Beman Dawes Opened: 2006-04-08  Last modified: 2007-07-02
    
-
    View all other issues in [intro.refs].
    
+
    529. The standard encourages redundant and confusing preconditions
    
+
    Section: 17.6.3.11 [res.on.required] Status: NAD Editorial
+ Submitter: David Abrahams Opened: 2005-10-25  Last modified: 2008-03-13
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-1.2 Normative references [intro.refs] of the WP currently refers to ISO/IEC
-9899:1990, Programming languages - C. Should that be changed to ISO/IEC
-9899:1999?
-
    
-
    
-What impact does this have on the library?
+17.4.3.8/1 says:
 
    
 
+
    
+Violation of the preconditions specified in a function's 
+Required behavior: paragraph results in undefined behavior unless the 
+function's Throws: paragraph specifies throwing an exception when the 
+precondition is violated.
+
    
 
-
    Proposed resolution:
    
 
    
-In 1.2/1 [intro.refs] of the WP, change:
+This implies that a precondition violation can lead to defined
+behavior.  That conflicts with the only reasonable definition of
+precondition: that a violation leads to undefined behavior.  Any other
+definition muddies the waters when it comes to analyzing program
+correctness, because precondition violations may be routinely done in
+correct code (e.g. you can use std::vector::at with the full
+expectation that you'll get an exception when your index is out of
+range, catch the exception, and continue).  Not only is it a bad
+example to set, but it encourages needless complication and redundancy
+in the standard.  For example:
 
    
-
    
-
      
-
    • ISO/IEC 9899:19901999 + TC1 + TC2, Programming languages - C
      • 
-
    
-
    
 
+
      21 Strings library 
+  21.3.3 basic_string capacity
 
+  void resize(size_type n, charT c);
 
-
    Rationale:
    
-Recommend NAD, fixed editorially.
+  5 Requires: n <= max_size()
+  6 Throws: length_error if n > max_size().
+  7 Effects: Alters the length of the string designated by *this as follows:
+
    
 
+
    
+The Requires clause is entirely redundant and can be dropped.  We
+could make that simplifying change (and many others like it) even
+without changing 17.4.3.8/1; the wording there just seems to encourage
+the redundant and error-prone Requires: clause.
+
    
 
+
    [
+Batavia:  Alan and Pete to work.
+]
    
 
 
+
    [
+Bellevue:  NAD Editorial, this group likes 
+N2121,
+Pete agrees, accepting it is Pete's business.
+General agreement that precondition violations are synonymous with UB.
+]
    
 
-
    
-
    572. Oops, we gave 507 WP status
    
-
    Section: 26.5 [rand], TR1 5.1 [tr.rand] Status: NAD
- Submitter: Howard Hinnant Opened: 2006-04-11  Last modified: 2007-04-18
    
-
    View other active issues in [rand].
    
-
    View all other issues in [rand].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
-
    
-In Berlin, as a working group, we voted in favor of N1932 which makes issue 507 moot:
-variate_generator has been eliminated.  Then in full committee we voted to give
-this issue WP status (mistakenly).
-
    
 
 
 
    Proposed resolution:
    
 
    
-Strike the proposed resolution of issue 507.
+1. Change 17.4.3.8/1 to read:
 
    
-
    [
-post-Portland:  Walter and Howard recommend NAD.  The proposed resolution of 507 no longer
-exists in the current WD.
-]
    
-
 
+
    
+Violation of the preconditions specified in a function's
+Required behavior: paragraph results in undefined behavior
+unless the function's Throws: paragraph specifies throwing
+an exception when the precondition is violated.
+
    
 
-
    Rationale:
    
 
    
-NAD.  Will be moot once
-N2135
-is adopted.
+2. Go through and remove redundant Requires: clauses.  Specifics to be
+   provided by Dave A.
 
    
 
+
    [
+Berlin: The LWG requests a detailed survey of part 2 of the proposed resolution.
+]
    
 
 
+
    [
+Alan provided the survey
+N2121.
+]
    
 
 
-
    
-
    579. erase(iterator) for unordered containers should not return an iterator
    
-
    Section: 23.2.5 [unord.req] Status: NAD
- Submitter: Joaquín M López Muñoz Opened: 2006-06-13  Last modified: 2008-03-12
    
-
    View other active issues in [unord.req].
    
-
    View all other issues in [unord.req].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
-
    
-See
-N2023
-for full discussion.
-
    
 
 
-
    Proposed resolution:
    
-
    
-Option 1:
-
    
 
-
    
-The problem can be eliminated by omitting the requirement that a.erase(q) return an 
-iterator. This is, however, in contrast with the equivalent requirements for other 
-standard containers.
-
    
 
-
    
-Option 2:
-
    
 
+
    
+
    536. Container iterator constructor and explicit convertibility
    
+
    Section: 23.2 [container.requirements] Status: Dup
+ Submitter: Joaquín M López Muñoz Opened: 2005-12-17  Last modified: 2007-04-18
    
+
    View other active issues in [container.requirements].
    
+
    View all other issues in [container.requirements].
    
+
    View all issues with Dup status.
    
+
    Duplicate of: 589
    
+
    Discussion:
    
 
    
-a.erase(q) can be made to compute the next iterator only when explicitly requested: 
-the technique consists in returning a proxy object implicitly convertible to iterator, so 
-that
+The iterator constructor X(i,j) for containers as defined in 23.1.1 and
+23.2.2 does only require that i and j be input iterators but
+nothing is said about their associated value_type. There are three
+sensible
+options:
 
    
-
-
    iterator q1=a.erase(q);
-
    
-
+
      
+
    1. iterator's value_type is exactly X::value_type (modulo cv).
      2. 
+
    2. iterator's value_type is *implicitly* convertible to X::value_type.
      3. 
+
    3. iterator's value_type is *explicitly* convertible to X::value_type.
      4. 
+
    
 
    
-works as expected, while
+The issue has practical implications, and stdlib vendors have
+taken divergent approaches to it: Dinkumware follows 2,
+libstdc++ follows 3.
 
    
-
-
    a.erase(q);
-
    
-
 
    
-does not ever invoke the conversion-to-iterator operator, thus avoiding the associated 
-computation. To allow this technique, some sections of TR1 along the line "return value 
-is an iterator..." should be changed to "return value is an unspecified object implicitly 
-convertible to an iterator..." Although this trick is expected to work transparently, it can 
-have some collateral effects when the expression a.erase(q) is used inside generic 
-code.
+The same problem applies to the definition of insert(p,i,j) for
+sequences and insert(i,j) for associative contianers, as well as
+assign.
 
    
 
+
    [
+The following added by Howard and the example code was originally written by
+Dietmar.
+]
    
 
-
-
    Rationale:
    
 
    
-N2023
-was discussed in Portland and the consensus was that there appears to be
-no need for either change proposed in the paper.  The consensus opinion
-was that since the iterator could serve as its own proxy, there appears
-to be no need for the change. In general, "converts to" is undesirable
-because it interferes with template matching.
+Valid code below?
 
    
 
-
    
-Post Toronto:  There does not at this time appear to be consensus with the Portland consensus. 
-
    
+
    #include <vector> 
+#include <iterator> 
+#include <iostream> 
+
+struct foo 
+{ 
+    explicit foo(int) {} 
+}; 
 
+int main() 
+{ 
+    std::vector<int> v_int; 
+    std::vector<foo> v_foo1(v_int.begin(), v_int.end()); 
+    std::vector<foo> v_foo2((std::istream_iterator<int>(std::cin)), 
+                             std::istream_iterator<int>()); 
+} 
+
    
 
    [
-Bellevue:
+Berlin: Some support, not universal, for respecting the explicit qualifier.
 ]
    
 
 
-
    
-The Bellevue review of this issue reached consensus with the Portland
-consensus, in contravention of the Toronto non-consensus. Common
-implementations have the iterator readily available, and most common
-uses depend on the iterator being returned.
-
    
+
+
+
    Proposed resolution:
    
 
 
 
@@ -9820,636 +11460,421 @@ uses depend on the iterator being returned.
 
 
 
    
-
    583. div() for unsigned integral types
    
-
    Section: 26.8 [c.math] Status: NAD
- Submitter: Beman Dawes Opened: 2006-06-15  Last modified: 2007-07-25
    
-
    View all other issues in [c.math].
    
-
    View all issues with NAD status.
    
+
    544. minor NULL problems in C.2
    
+
    Section: C.2 [diff.library] Status: NAD Editorial
+ Submitter: Martin Sebor Opened: 2005-11-25  Last modified: 2007-04-24
    
+
    View other active issues in [diff.library].
    
+
    View all other issues in [diff.library].
    
+
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-There is no div() function for unsigned integer types.
+According to C.2.2.3, p1, "the macro NULL, defined in any of <clocale>,
+<cstddef>, <cstdio>, <cstdlib>, <cstring>, <ctime>,
+or <cwchar>." This is consistent with the C standard.
 
    
 
    
-There are several possible resolutions.  The simplest one is noted below.  Other
-possibilities include a templated solution.
+However, Table 95 in C.2 fails to mention <clocale> and <cstdlib>.
+
    
+
    
+In addition, C.2, p2 claims that "The C++ Standard library provides
+54 standard macros from the C library, as shown in Table 95." While
+table 95 does have 54 entries, since a couple of them (including the
+NULL macro) are listed more than once, the actual number of macros
+defined by the C++ Standard Library may not be 54.
 
    
 
 
 
    Proposed resolution:
    
 
    
-Add to 26.7 [lib.c.math] paragraph 8:
+I propose we add <clocale> and <cstdlib> to Table 96 and remove the
+number of macros from C.2, p2 and reword the sentence as follows:
 
    
+
    
+The C++ Standard library provides 54 standard macros from
+defines a number macros corresponding to those defined by the C 
+Standard library, as shown in Table 96.
+
    
 
-
    struct udiv_t div(unsigned, unsigned);
-struct uldiv_t div(unsigned long, unsigned long);
-struct ulldiv_t div(unsigned long long, unsigned long long);
-
    
-
+
    [
+Portland:  Resolution is considered editorial.  It will be incorporated into the WD.
+]
    
 
 
-
    Rationale:
    
-Toronto:  C99 does not have these unsigned versions because
-the signed version exist just to define the implementation-defined behavior
-of signed integer division.  Unsigned integer division has no implementation-defined
-behavior and thus does not need this treatment.
 
 
 
 
 
 
    
-
    584. missing int pow(int,int) functionality
    
-
    Section: 26.8 [c.math] Status: NAD
- Submitter: Beman Dawes Opened: 2006-06-15  Last modified: 2007-07-25
    
-
    View all other issues in [c.math].
    
+
    546. _Longlong and _ULonglong are integer types
    
+
    Section: TR1 5.1.1 [tr.rand.req] Status: NAD
+ Submitter: Matt Austern Opened: 2006-01-10  Last modified: 2009-07-15
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-There is no pow() function for any integral type.
+The TR sneaks in two new integer types, _Longlong and _Ulonglong, in [tr.c99].
+The rest of the TR should use that type.  I believe this affects two places.
+First, the random number requirements, 5.1.1/10-11, lists all of the types with
+which template parameters named IntType and UIntType may be instantiated.
+_Longlong (or "long long", assuming it is added to C++0x) should be added to the
+IntType list, and UIntType (again, or "unsigned long long") should be added to
+the UIntType list.  Second, 6.3.2 lists the types for which hash<> is
+required to be instantiable. _Longlong and _Ulonglong should be added to that
+list, so that people may use long long as a hash key.
 
    
 
+
    [
+2009-07 Frankfurt
+]
    
 
-
    Proposed resolution:
    
+
+
    
 
    
-Add something like:
+We are not going to fix TR1.
+
    
+
    
+The paper "long long goes to the library" addresses the integration of
+long long into the C++0x library.
+
    
+
    
+Move to NAD.
 
    
+
    
 
-
    template< typename T>
-T power( T x, int n );
-// requires: n >=0
-
    
 
 
-
    Rationale:
    
-Toronto:  We already have double pow(integral, integral) from 26.8 [c.math] p11.
+
    Proposed resolution:
    
+
    
+
    
 
 
 
 
 
 
    
-
    587. iststream ctor missing description
    
-
    Section: D.7.2.1 [depr.istrstream.cons] Status: NAD Editorial
- Submitter: Martin Sebor Opened: 2006-06-22  Last modified: 2007-05-11
    
-
    View all issues with NAD Editorial status.
    
+
    547. division should be floating-point, not integer
    
+
    Section: 26.5 [rand], TR1 5.1 [tr.rand] Status: NAD
+ Submitter: Matt Austern Opened: 2006-01-10  Last modified: 2007-04-18
    
+
    View all other issues in [rand].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
-        
    
-
-The  iststream(char*, streamsize)  ctor is  in  the class
-synopsis  in D.7.2  but its  signature is  missing in  the description
-below (in D.7.2.1).
-
-        
    
-    
+
    
+Paragraph 10 describes how a variate generator uses numbers produced by an
+engine to pass to a generator. The sentence that concerns me is: "Otherwise, if
+the value for engine_value_type::result_type is true and the value for
+Distribution::input_type is false [i.e. if the engine produces integers and the
+engine wants floating-point values], then the numbers in s_eng are divided by
+engine().max() - engine().min() + 1 to obtain the numbers in s_e." Since the
+engine is producing integers, both the numerator and the denominator are
+integers and we'll be doing integer division, which I don't think is what we
+want. Shouldn't we be performing a conversion to a floating-point type first?
+
    
 
-    
    Proposed resolution:
    
-        
    
 
-This seems like a simple editorial issue and the missing signature can
-be added to the one for const char* in paragraph 2.
+
    Proposed resolution:
    
 
-        
    
 
-
    [
-post Oxford: Noted that it is already fixed in
-N2284
-]
    
+
    Rationale:
    
+
    
+Recommend NAD as the affected section is now gone and so the issue is moot.
+N2111.
+
    
 
 
-    
 
 
 
 
    
-
    590. Type traits implementation latitude should be removed for C++0x
    
-
    Section: 20.6 [meta], TR1 4.9 [tr.meta.req] Status: NAD Editorial
- Submitter: Beman Dawes Opened: 2006-08-10  Last modified: 2007-05-11
    
-
    View other active issues in [meta].
    
-
    View all other issues in [meta].
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
+
    548. May random_device block?
    
+
    Section: 26.5.6 [rand.device], TR1 5.1.6 [tr.rand.device] Status: NAD
+ Submitter: Matt Austern Opened: 2006-01-10  Last modified: 2007-10-18
    
+
    View all other issues in [rand.device].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
    
-20.4.9 [lib.meta.req], Implementation requirements, provides latitude for type
-traits implementers that is not needed in C++0x. It includes the wording:
+Class random_device "produces non-deterministic random numbers", using some
+external source of entropy. In most real-world systems, the amount of available
+entropy is limited. Suppose that entropy has been exhausted. What is an
+implementation permitted to do? In particular, is it permitted to block
+indefinitely until more random bits are available, or is the implementation
+required to detect failure immediately? This is not an academic question. On
+Linux a straightforward implementation would read from /dev/random, and "When
+the entropy pool is empty, reads to /dev/random will block until additional
+environmental noise is gathered." Programmers need to know whether random_device
+is permitted to (or possibly even required to?) behave the same way.
 
    
 
-
    
-[Note: the latitude granted to implementers in this clause is temporary,
-and is expected to be removed in future revisions of this document. -- end note]
-
    
+
    [
+Berlin: Walter: N1932 considers this NAD. Does the standard specify whether std::cin
+may block?
+]
    
+
 
 
    
-Note:
-N2157: Minor Modifications to the type traits Wording
-also has the intent of removing this wording from the WP.
+See N2391 and
+N2423
+for some further discussion.
 
    
 
 
-
 
    Proposed resolution:
    
 
    
-Remove 20.4.9 [lib.meta.req] in its entirety from the WP.
+Adopt the proposed resolution in
+N2423 (NAD).
 
    
 
-
    [
-post-Oxford: Recommend NAD Editorial.  This resolution is now in the
-current working draft.
-]
    
-
-
-
 
 
 
 
 
    
-
    591. Misleading "built-in
    
-
    Section: 18.3.1.2 [numeric.limits.members] Status: NAD Editorial
- Submitter: whyglinux Opened: 2006-08-08  Last modified: 2007-07-02
    
-
    View all other issues in [numeric.limits.members].
    
+
    549. Undefined variable in binomial_distribution
    
+
    Section: 26.5.8 [rand.dist], TR1 5.1.7.5 [tr.rand.dist.bin] Status: NAD Editorial
+ Submitter: Matt Austern Opened: 2006-01-10  Last modified: 2007-04-24
    
+
    View all other issues in [rand.dist].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-18.2.1.2 numeric_limits members [lib.numeric.limits.members]
-Paragraph 7:
-
    
-
    
-"For built-in integer types, the number of non-sign bits in the
-representation."
-
    
-
-
    
-26.1 Numeric type requirements [lib.numeric.requirements]
-Footnote:
-
    
-
-
    
-"In other words, value types. These include built-in arithmetic types,
-pointers, the library class complex, and instantiations of valarray for
-value types."
-
    
-
-
    
-Integer types (which are bool, char, wchar_t, and the signed and
-unsigned integer types) and arithmetic types (which are integer and
-floating types) are all built-in types and thus there are no
-non-built-in (that is, user-defined) integer or arithmetic types. Since
-the redundant "built-in" in the above 2 sentences can mislead that
-there may be built-in or user-defined integer and arithmetic types
-(which is not correct), the "built-in" should be removed.
+Paragraph 1 says that "A binomial distributon random distribution produces
+integer values i>0 with p(i) = (n choose i) * p*i * (1-p)^(t-i), where t and
+p are the parameters of the distribution. OK, that tells us what t, p, and i
+are. What's n?
 
    
 
 
 
    Proposed resolution:
    
 
    
-18.2.1.2 numeric_limits members [lib.numeric.limits.members]
-Paragraph 7:
-
    
-
    
-"For built-in integer types, the number of non-sign bits in the
-representation."
-
    
-
-
    
-26.1 Numeric type requirements [lib.numeric.requirements]
-Footnote:
+Berlin: Typo: "n" replaced by "t" in N1932: see 26.3.7.2.2/1.
 
    
 
-
    
-"In other words, value types. These include built-in arithmetic types,
-pointers, the library class complex, and instantiations of valarray for
-value types."
-
    
-
+
    [
+Portland:  Subsumed by N2111.
+]
    
 
-
    Rationale:
    
-
    
-Recommend NAD / Editorial.  The proposed resolution is accepted as editorial.
-
    
 
 
 
 
 
 
    
-
    592. Incorrect treatment of rdbuf()->close() return type
    
-
    Section: 27.9.1.9 [ifstream.members] Status: NAD Editorial
- Submitter: Christopher Kohlhoff Opened: 2006-08-17  Last modified: 2008-07-02
    
-
    View all other issues in [ifstream.members].
    
+
    553. very minor editorial change intptr_t / uintptr_t
    
+
    Section: 18.4.1 [cstdint.syn], TR1 8.22.1 [tr.c99.cstdint.syn] Status: NAD Editorial
+ Submitter: Paolo Carlini Opened: 2006-01-30  Last modified: 2007-07-02
    
+
    View all other issues in [cstdint.syn].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-I just spotted a minor problem in 27.8.1.7
-[lib.ifstream.members] para 4 and also 27.8.1.13
-[lib.fstream.members] para 4. In both places it says:
-
    
-
    
-
    void close();
-
    
-
    
-Effects: Calls rdbuf()->close() and, if that function returns false, ...
+In the synopsis, some types are identified as optional: int8_t, int16_t,
+and so on, consistently with C99, indeed.
 
    
-
    
 
    
-However, basic_filebuf::close() (27.8.1.2) returns a pointer to the
-filebuf on success, null on failure, so I think it is meant to
-say "if that function returns a null pointer". Oddly, it is
-correct for basic_ofstream.
+On the other hand, intptr_t and uintptr_t, are not marked as such and
+probably should, consistently with C99, 7.18.1.4.
 
    
 
 
 
    Proposed resolution:
    
 
    
-Change 27.9.1.9 [ifstream.members], p5:
-
    
-
-
    
-Effects: Calls rdbuf()->close() and, if that function
-fails (returns false a null pointer),
-calls setstate(failbit) (which may throw ios_base::failure
-(27.4.4.3)).
-
    
-
-
    
-Change 27.9.1.17 [fstream.members], p5:
+Change 18.4.1 [cstdint.syn]:
 
    
 
-
    
-Effects: Calls rdbuf()->close() and, if that function
-fails (returns false a null pointer),
-calls setstate(failbit) (which may throw ios_base::failure
-(27.4.4.3)).
-
    
+
    ...
+typedef signed integer type intptr_t;    // optional
+...
+typedef unsigned integer type uintptr_t;    // optional
+...
+
    
 
 
 
-
    [
-Kona (2007): Proposed Disposition: NAD, Editorial
-]
    
+
    Rationale:
    
+Recommend NAD and fix as editorial with the proposed resolution.
 
 
 
 
 
 
    
-
    594. Disadvantages of defining Swappable in terms of CopyConstructible and Assignable
    
-
    Section: X [utility.arg.requirements] Status: NAD Editorial
- Submitter: Niels Dekker Opened: 2006-11-02  Last modified: 2008-09-23
    
-
    View all other issues in [utility.arg.requirements].
    
-
    View all issues with NAD Editorial status.
    
+
    554. Problem with lwg DR 184 numeric_limits<bool>
    
+
    Section: 18.3.1.5 [numeric.special] Status: NAD
+ Submitter: Howard Hinnant Opened: 2006-01-29  Last modified: 2007-01-15
    
+
    View all other issues in [numeric.special].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-It seems undesirable to define the Swappable requirement in terms of
-CopyConstructible and Assignable requirements. And likewise, once the
-MoveConstructible and MoveAssignable requirements (N1860) have made it
-into the Working Draft, it seems undesirable to define the Swappable
-requirement in terms of those requirements. Instead, it appears
-preferable to have the Swappable requirement defined exclusively in
-terms of the existence of an appropriate swap function.
-
    
-
    
-Section 20.1.4 [lib.swappable] of the current Working Draft (N2009)
-says:
-
    
-
    
-The Swappable requirement is met by satisfying one or more of the
-following conditions:
    
-
      
-
    • 
-T is Swappable if T satisfies the CopyConstructible requirements
-(20.1.3) and the Assignable requirements (23.1);
-
      • 
-
    • 
-T is Swappable if a namespace scope function named swap exists in the
-same namespace as the definition of T, such that the expression
-swap(t,u) is valid and has the semantics described in Table 33.
-
      • 
-
    
-
    
-I can think of three disadvantages of this definition:
-
      
-
    1. 
-If a client's type T satisfies the first condition (T is both
-CopyConstructible and Assignable), the client cannot stop T from
-satisfying the Swappable requirement without stopping T from
-satisfying the first condition.
-
      
-A client might want to stop T from satisfying the Swappable
-requirement, because swapping by means of copy construction and
-assignment might throw an exception, and she might find a throwing
-swap unacceptable for her type. On the other hand, she might not feel
-the need to fully implement her own swap function for this type. In
-this case she would want to be able to simply prevent algorithms that
-would swap objects of type T from being used, e.g., by declaring a
-swap function for T, and leaving this function purposely undefined.
-This would trigger a link error, if an attempt would be made to use
-such an algorithm for this type. For most standard library
-implementations, this practice would indeed have the effect of
-stopping T from satisfying the Swappable requirement.
-
      
-
      2. 
-
    2. 
-A client's type T that does not satisfy the first condition can not be
-made Swappable by providing a specialization of std::swap for T.
-
      
-While I'm aware about the fact that people have mixed feelings about
-providing a specialization of std::swap, it is well-defined to do so.
-It sounds rather counter-intuitive to say that T is not Swappable, if
-it has a valid and semantically correct specialization of std::swap.
-Also in practice, providing such a specialization will have the same
-effect as satisfying the Swappable requirement.
-
      
-
      3. 
-
    3. 
-For a client's type T that satisfies both conditions of the Swappable
-requirement, it is not specified which of the two conditions prevails.
-After reading section 20.1.4 [lib.swappable], one might wonder whether
-objects of T will be swapped by doing copy construction and
-assignments, or by calling the swap function of T.
-
      
-I'm aware that the intention of the Draft is to prefer calling the
-swap function of T over doing copy construction and assignments. Still
-in my opinion, it would be better to make this clear in the wording of
-the definition of Swappable. 
+I believe we have a bug in the resolution of:
+lwg 184
+(WP status).
 
      
-
      4. 
-
    
+
 
    
-I would like to have the Swappable requirement defined in such a way
-that the following code fragment will correctly swap two objects of a
-type T, if and only if T is Swappable:
+The resolution spells out each member of numeric_limits<bool>.
+The part I'm having a little trouble with is:
 
    
-
       using std::swap;
-   swap(t, u);  // t and u are of type T.
-
    
+
    static const bool traps = false;
+
    
+
 
    
-This is also the way Scott Meyers recommends calling a swap function,
-in Effective C++, Third Edition, item 25.
+Should this not be implementation defined?  Given:
 
    
+
+
    int main()
+{
+     bool b1 = true;
+     bool b2 = false;
+     bool b3 = b1/b2;
+}
+
    
+
 
    
-Most aspects of this issue have been dealt with in a discussion on
-comp.std.c++ about the Swappable requirement, from 13 September to 4
-October 2006, including valuable input by David Abrahams, Pete Becker,
-Greg Herlihy, Howard Hinnant and others.
+If this causes a trap, shouldn't numeric_limits<bool>::traps be
+true?
 
    
 
+
 
    Proposed resolution:
    
 
    
-Change section 20.1.4 [lib.swappable] as follows:
+Change 18.2.1.5p3:
 
    
-
    
-The Swappable requirement is met by satisfying
-one or more of the following conditions:
-the following condition:
    
-
      
 
-
    • 
-T is Swappable if T satisfies the CopyConstructible requirements
-(20.1.3) and the Assignable requirements (23.1);
-
      • 
-
    • 
-
-T is Swappable if a namespace scope function named swap exists in the
-same namespace as the definition of T, such that the expression
-swap(t,u) is valid and has the semantics described in Table 33.
-
-T is Swappable if an unqualified function call swap(t,u) is valid
-within the namespace std, and has the semantics described in Table 33.
-
      • 
-
    
+
    
+-3- The specialization for bool shall be provided as follows: 
    
+
    namespace std { 
+   template <> class numeric_limits<bool> {
+      ...
+      static const bool traps = false implementation-defined;
+      ...
+   };
+}
+
    
 
    
 
-
-
    Rationale:
    
-
    
-Recommend NAD.  Concepts, specifically
-N2082
-and
-N2084,
-will essentially rewrite this section and provide the desired semantics.
-
    
-
 
    [
-San Francisco:
+Redmond:  NAD because traps refers to values, not operations.  There is no bool
+value that will trap.
 ]
    
 
 
-
    
-Solved by
-N2774.
-
    
 
 
 
 
 
 
    
-
    615. Inconsistencies in Section 21.4
    
-
    Section: 21.6 [c.strings] Status: NAD Editorial
- Submitter: Bo Persson Opened: 2006-12-11  Last modified: 2007-04-24
    
-
    View all other issues in [c.strings].
    
+
    555. TR1, 8.21/1: typo
    
+
    Section: TR1 8.21 [tr.c99.boolh] Status: NAD Editorial
+ Submitter: Paolo Carlini Opened: 2006-02-02  Last modified: 2007-04-24
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-In the current draft N2134, 21.4/1 says
-
    
-
    
-"Tables 59,228) 60, 61, 62,and 63 229) 230) describe headers <cctype>, 
-<cwctype>, <cstring>, <cwchar>, and <cstdlib> (character conversions), 
-respectively."
-
    
-
    
-Here footnote 229 applies to table 62, not table 63.
-
    
-
    
-Also, footnote 230 lists the new functions in table 63, "atoll, strtoll, 
-strtoull, strtof, and strtold added by TR1". However, strtof is not present 
-in table 63.
+This one, if nobody noticed it yet, seems really editorial:
+s/cstbool/cstdbool/
 
    
 
 
 
    Proposed resolution:
    
 
    
+Change 8.21p1:
 
    
+
    
+-1- The header behaves as if it defines the additional macro defined in
+<cstdbool> by including the header <cstdbool>.
+
    
+
+
    [
+Redmond:  Editorial.
+]
    
 
 
-
    Rationale:
    
-
    
-Recommend NAD, editorial.  Send to Pete.
-
    
 
 
 
 
 
 
    
-
    626. new Remark clauses not documented
    
-
    Section: 17.5.1.4 [structure.specifications] Status: NAD Editorial
- Submitter: Martin Sebor Opened: 2007-01-20  Last modified: 2008-02-25
    
-
    View other active issues in [structure.specifications].
    
-
    View all other issues in [structure.specifications].
    
+
    557. TR1: div(_Longlong, _Longlong) vs div(intmax_t, intmax_t)
    
+
    Section: 18.4 [cstdint], TR1 8.22 [tr.c99.cstdint] Status: NAD Editorial
+ Submitter: Paolo Carlini Opened: 2006-02-06  Last modified: 2008-07-02
    
+
    View all other issues in [cstdint].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
-        
    
-
-The Remark clauses newly  introduced into the Working Paper 
-(N2134)
-are  not mentioned  in  17.5.1.4 [structure.specifications] where  we list  the
-meaning  of Effects, Requires,  and other  clauses (with
-the exception  of Notes which are documented  as informative in
-17.5.1.2 [structure.summary], p2, and which they replace in many cases).
-
-        
    
-        
    
-
-Propose add a bullet for Remarks along with a brief description.
-
-        
    
-
    [
-Batavia:  Alan and Pete to work.
-]
    
-
-
-
    [
-Bellevue: Already resolved in current working paper.
-]
    
-
-
-
-
    Proposed resolution:
    
 
    
+I'm seeing a problem with such overloads: when, _Longlong == intmax_t ==
+long long we end up, essentially, with the same arguments and different
+return types (lldiv_t and imaxdiv_t, respectively). Similar issue with
+abs(_Longlong) and abs(intmax_t), of course.
+
    
+
    
+Comparing sections 8.25 and 8.11, I see an important difference,
+however: 8.25.3 and 8.25.4 carefully describe div and abs for _Longlong
+types (rightfully, because not moved over directly from C99), whereas
+there is no equivalent in 8.11: the abs and div overloads for intmax_t
+types appear only in the synopsis and are not described anywhere, in
+particular no mention in 8.11.2 (at variance with 8.25.2).
+
    
+
    
+I'm wondering whether we really, really, want div and abs for intmax_t...
 
    
 
 
 
+
    Proposed resolution:
    
 
 
-
    
-
    627. Low memory and exceptions
    
-
    Section: 18.6.1.1 [new.delete.single] Status: NAD
- Submitter: P.J. Plauger Opened: 2007-01-23  Last modified: 2008-02-25
    
-
    View all other issues in [new.delete.single].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
-
    
-I recognize the need for nothrow guarantees in the exception reporting
-mechanism, but I strongly believe that implementors also need an escape hatch
-when memory gets really low. (Like, there's not enough heap to construct and
-copy exception objects, or not enough stack to process the throw.) I'd like to
-think we can put this escape hatch in 18.6.1.1 [new.delete.single],
-operator new, but I'm not sure how to do it. We need more than a
-footnote, but the wording has to be a bit vague. The idea is that if
-new can't allocate something sufficiently small, it has the right to
-abort/call terminate/call unexpected.
-
    
 
 
    [
-Bellevue: NAD.  1.4p2 specifies a program must behave correctly "within
-its resource limits", so no further escape hatch is necessary.
+Portland: no consensus.
 ]
    
 
 
+
    Rationale:
    
+
    [
+Batavia, Bill: The <cstdint> synopsis in TR1 8.11.1 [tr.c99.cinttypes.syn] contains:
+]
    
 
-
    Proposed resolution:
    
-
    
-
    
-
-
+
    intmax_t imaxabs(intmax_t i);
+intmax_t abs(intmax_t i);
 
+imaxdiv_t imaxdiv(intmax_t numer, intmax_t denom);
+imaxdiv_t div(intmax_t numer, intmax_t denom);
+
    
 
+
    [
+and in TR1 8.11.2 [tr.c99.cinttypes.def]:
+]
    
 
-
    
-
    631. conflicting requirements for BinaryPredicate
    
-
    Section: 25 [algorithms] Status: NAD Editorial
- Submitter: James Kanze Opened: 2007-01-31  Last modified: 2008-09-26
    
-
    View all other issues in [algorithms].
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
-
    
-The general requirements for BinaryPredicate (in 25 [algorithms]/8) contradict the implied specific requirements for
-some functions. In particular, it says that:
-
    
 
 
    
-[...] if an algorithm takes BinaryPredicate binary_pred
-as its argument and first1 and first2 as its
-iterator arguments, it should work correctly in the construct if
-(binary_pred (*first1 , *first2 )){...}.
-BinaryPredicate always takes the first iterator type as its
-first argument, that is, in those cases when T value is
-part of the signature, it should work correctly in the context of if
-(binary_pred (*first1 , value)){...}.
+The header defines all functions, types, and macros the same as C99
+subclause 7.8.
 
    
 
-
    
-In the description of upper_bound (25.5.3.2 [upper.bound]/2), however, the use is described as
-"!comp(value, e)", where e is an
-element of the sequence (a result of dereferencing
-*first).
-
    
-
-
    
-In the description of lexicographical_compare, we have both
-"*first1 < *first2" and "*first2
-< *first1" (which presumably implies "comp(
-*first1, *first2 )" and "comp( *first2,
-*first1 )".
-
    
-
 
    [
-Toronto:  Moved to Open.  ConceptGCC seems to get lower_bound
-and upper_bound to work withoutt these changes.
+This is as much definition as we give for most other C99 functions,
+so nothing need change. We might, however, choose to add the footnote:
 ]
    
 
 
-
-
-
    Proposed resolution:
    
-
    
-Logically, the BinaryPredicate is used as an ordering
-relationship, with the semantics of "less than".  Depending on the
-function, it may be used to determine equality, or any of the inequality
-relationships; doing this requires being able to use it with either
-parameter first.  I would thus suggest that the requirement be:
-
    
-
 
    
-[...] BinaryPredicate always takes the first iterator
-value_type as one of its arguments, it is unspecified which. If
-an algorithm takes BinaryPredicate binary_pred as its
-argument and first1 and first2 as its
-iterator arguments, it should work correctly both in the construct
-if (binary_pred (*first1 , *first2 )){...} and
-if (binary_pred (*first2, *first1)){...}.  In
-those cases when T value is part of the signature, it
-should work correctly in the context of if (binary_pred
-(*first1 , value)){...} and of if (binary_pred
-(value, *first1)){...}. [Note: if the two
-types are not identical, and neither is convertable to the other, this
-may require that the BinaryPredicate be a functional object
-with two overloaded operator()() functions. --end note]
+[Note: These overloads for abs and div may well be equivalent to
+those that take long long arguments. If so, the implementation is
+responsible for avoiding conflicting declarations. -- end note]
 
    
 
-
    
-Alternatively, one could specify an order for each function. IMHO, this
-would be more work for the committee, more work for the implementors,
-and of no real advantage for the user: some functions, such as
-lexicographical_compare or equal_range, will still require both
-functions, and it seems like a much easier rule to teach that both
-functions are always required, rather than to have a complicated list of
-when you only need one, and which one.
-
    
-
-
-
    Rationale:
    
 
    [
-post San Francisco:
+Bellevue: NAD Editorial. Pete must add a footnote, as described below.
 ]
    
 
 
 
    
-Solved by
-N2759.
+
    [
+Looks like a real problem. Dietmar suggests div() return a template
+type. Matt: looks like imaxdiv_t is loosly defined. Can it be a typedef
+for lldiv_t when _Longlong == intmax_t? PJP seems to agree. We would
+need a non-normative note declaring that the types lldiv_t and imaxdiv_t
+may not be unique if intmax_t==_longlong.
+]
    
+
 
    
 
 
@@ -10458,47 +11883,45 @@ Solved by
 
 
 
    
-
    633. Return clause mentions undefined "type()"
    
-
    Section: 20.7.16.2.5 [func.wrap.func.targ] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2007-02-03  Last modified: 2007-07-02
    
+
    558. lib.input.iterators Defect
    
+
    Section: 24.2.2 [input.iterators] Status: NAD Editorial
+ Submitter: David Abrahams Opened: 2006-02-09  Last modified: 2007-04-24
    
+
    View all other issues in [input.iterators].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
+
    
 
    
-20.7.16.2.5 [func.wrap.func.targ], p4 says:
+  24.1.1 Input iterators [lib.input.iterators]
+
    
+
    
+  1 A class or a built-in type X satisfies the requirements of an
+  input iterator for the value type T if the following expressions are
+  valid, where U is the type of any specified member of type T, as
+  shown in Table 73.
+
    
+
    
+
    
+There is no capital U used in table 73.  There is a lowercase u, but
+that is clearly not meant to denote a member of type T.  Also, there's
+no description in 24.1.1 of what lowercase a means.  IMO the above
+should have been...Hah, a and b are already covered in 24.1/11, so maybe it
+should have just been:
 
    
-
    
-Returns: If type() == typeid(T), a pointer to the stored
-function target; otherwise a null pointer.
-
    
-
-
      
-
    1. 
-There exists neither a type, a typedef type, nor member
-function type() in class template function nor in the global or
-std namespace.
-
      2. 
-
    2. 
-Assuming that type should have been target_type(),
-this description would lead to false results, if T = cv
-void due to returns clause 20.7.16.2.5 [func.wrap.func.targ], p1.
-
      3. 
-
    
-
 
 
 
    Proposed resolution:
    
 
    
-Change 20.7.16.2.5 [func.wrap.func.targ], p4:
+Change 24.1.1p1:
 
    
-
 
    
-Returns: If type() target_type() == typeid(T) && typeid(T) !=
-typeid(void), a pointer to the stored function target;
-otherwise a null pointer.
+-1- A class or a built-in type X satisfies the requirements of an
+input iterator for the value type T if the following expressions 
+are valid, where U is the type of any specified member of type
+T, as shown in Table 73.
 
    
 
 
    [
-Pete: Agreed. It's editorial, so I'll fix it.
+Portland: Editorial.
 ]
    
 
 
@@ -10508,2498 +11931,2388 @@ Pete: Agreed. It's editorial, so I'll fix it.
 
 
 
    
-
    636. 26.5.2.3 valarray::operator[]
    
-
    Section: 26.6.2.3 [valarray.access] Status: NAD Editorial
- Submitter: Bo Persson Opened: 2007-02-11  Last modified: 2007-07-02
    
-
    View all other issues in [valarray.access].
    
-
    View all issues with NAD Editorial status.
    
+
    560. User-defined allocators without default constructor
    
+
    Section: X [allocator.requirements] Status: NAD
+ Submitter: Sergey P. Derevyago Opened: 2006-02-17  Last modified: 2007-04-18
    
+
    View other active issues in [allocator.requirements].
    
+
    View all other issues in [allocator.requirements].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
+
    1. The essence of the problem.
    
 
    
-The signature of the const operator[] has been changed to return a const 
-reference.
+User-defined allocators without default constructor are not explicitly
+supported by the standard but they can be supported just like std::vector
+supports elements without default constructor.
 
    
 
    
-The description in paragraph 1 still says that the operator returns by 
-value.
+As a result, there exist implementations that work well with such allocators
+and implementations that don't.
 
    
-
    [
-Pete recommends editorial fix.
-]
    
 
-
-
-
    Proposed resolution:
    
+
    2. The cause of the problem.
    
 
    
+1) The standard doesn't explicitly state this intent but it should. In
+particular, 20.1.5p5 explicitly state the intent w.r.t. the allocator
+instances that compare non-equal. So it can similarly state the intent w.r.t.
+the user-defined allocators without default constructor.
 
    
-
-
-
-
-
-
    
-
    637. [c.math]/10 inconsistent return values
    
-
    Section: 26.8 [c.math] Status: NAD Editorial
- Submitter: Bo Persson Opened: 2007-02-13  Last modified: 2007-07-26
    
-
    View all other issues in [c.math].
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
 
    
-26.8 [c.math], paragraph 10 has long lists of added signatures for float and long double 
-functions. All the signatures have float/long double return values, which is 
-inconsistent with some of the double functions they are supposed to 
-overload.
+2) Some container operations are obviously underspecified. In particular,
+21.3.7.1p2 tells:
 
    
-
-
-
    Proposed resolution:
    
+
    template<class charT, class traits, class Allocator>
+  basic_string<charT,traits,Allocator> operator+(
+    const charT* lhs,
+    const basic_string<charT,traits,Allocator>& rhs
+  );
+
    
 
    
-Change 26.8 [c.math], paragraph 10,
+Returns: basic_string<charT,traits,Allocator>(lhs) + rhs.
 
    
-
-
    float int ilogb(float);
-float long lrint(float);
-float long lround(float);
-float long long llrint(float);
-float long long llround(float);
-
-long double int ilogb(long double);
-long double long lrint(long double);
-long double long lround(long double);
-long double long long llrint(long double);
-long double long long llround(long double);
-
    
-
-
-
-
-
-
    
-
    639. Still problems with exceptions during streambuf IO
    
-
    Section: 27.7.1.2.3 [istream::extractors], 27.7.2.6.3 [ostream.inserters] Status: NAD
- Submitter: Daniel Krügler Opened: 2007-02-17  Last modified: 2007-10-10
    
-
    View all other issues in [istream::extractors].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
+
    
 
    
-There already exist two active DR's for the wording of 27.7.1.2.3 [istream::extractors]/13
-from 14882:2003(E), namely 64 and 413.
+That leads to the basic_string<charT,traits,Allocator>(lhs, Allocator()) call.
+Obviously, the right requirement is:
 
    
-
+
    
+Returns: basic_string<charT,traits,Allocator>(lhs, rhs.get_allocator()) + rhs.
+
    
 
    
-Even with these proposed corrections, already maintained in N2134,
-I have the feeling, that the current wording does still not properly
-handle the "exceptional" situation. The combination of para 14
+It seems like a lot of DRs can be submitted on this "Absent call to
+get_allocator()" topic.
 
    
 
-
    
-"[..] Characters are extracted and inserted until
-any of the following occurs:
+
    3. Proposed actions.
    
+
    
+1) Explicitly state the intent to allow for user-defined allocators without
+default constructor in 20.1.5 Allocator requirements.
 
    
 
    
-[..]
+2) Correct all the places, where a correct allocator object is available
+through the get_allocator() call but default Allocator() gets passed instead.
 
    
+
    4. Code sample.
    
 
    
-- an exception occurs (in which case the exception is caught)."
-
    
-
+Let's suppose that the following memory pool is available:
+
    
+
    class mem_pool {
+      // ...
+      void* allocate(size_t size);
+      void deallocate(void* ptr, size_t size);
+};
+
    
 
    
-and 15
+So the following allocator can be implemented via this pool:
 
    
+
    class stl_allocator {
+      mem_pool& pool;
 
-
    
-"If the function inserts no characters, it calls setstate(failbit),
-which
-may throw ios_base::failure (27.4.4.3). If it inserted no characters
-because it caught an exception thrown while extracting characters
-from *this and failbit is on in exceptions() (27.4.4.3), then the
-caught
-exception is rethrown."
-
    
+ public:
+      explicit stl_allocator(mem_pool& mp) : pool(mp) {}
+      stl_allocator(const stl_allocator& sa) : pool(sa.pool) {}
+      template <class U>
+      stl_allocator(const stl_allocator<U>& sa)  : pool(sa.get_pool()) {}
+      ~stl_allocator() {}
+
+      pointer allocate(size_type n, std::allocator<void>::const_pointer = 0)
+      {
+       return (n!=0) ? static_cast<pointer>(pool.allocate(n*sizeof(T))) : 0;
+      }
+
+      void deallocate(pointer p, size_type n)
+      {
+       if (n!=0) pool.deallocate(p, n*sizeof(T));
+      }
 
+      // ...
+};
+
    
 
    
-both in N2134 seems to imply that any exception, which occurs
-*after* at least one character has been inserted is caught and lost
-for
-ever. It seems that even if failbit is on in exceptions() rethrow is
-not
-allowed due to the wording "If it inserted no characters because it
-caught an exception thrown while extracting".
+Then the following code works well on some implementations and doesn't work on
+another:
 
    
-
+
    typedef basic_string<char, char_traits<char>, stl_allocator<char> > 
+  tl_string;
+mem_pool mp;
+tl_string s1("abc", stl_allocator<int>(mp));
+printf("(%s)\n", ("def"+s1).c_str());
+
    
 
    
-Is this behaviour by design?
+In particular, on some implementations the code can't be compiled without
+default stl_allocator() constructor.
 
    
-
 
    
-I would like to add that its output counterpart in 27.7.2.6.3 [ostream.inserters]/7-9
-(also
-N2134) does not demonstrate such an exception-loss-behaviour.
-On the other side, I wonder concerning several subtle differences
-compared to input::
+The obvious way to solve the compile-time problems is to intentionally define
+a NULL pointer dereferencing default constructor
 
    
+
    stl_allocator() : pool(*static_cast<mem_pool*>(0)) {}
+
    
 
    
-1) Paragraph 8 says at its end:
+in a hope that it will not be called. The problem is that it really gets
+called by operator+(const char*, const string&) under the current 21.3.7.1p2
+wording.
 
    
 
-
    
-"- an exception occurs while getting a character from sb."
-
    
 
+
    Proposed resolution:
    
 
    
-Note that there is nothing mentioned which would imply that such
-an exception will be caught compared to 27.7.1.2.3 [istream::extractors]/14.
 
    
 
+
+
    Rationale:
    
 
    
-2) Paragraph 9 says:
+Recommend NAD.  operator+() with string already requires the desired
+semantics of copying the allocator from one of the strings (lhs when there is a choice).
 
    
 
-
    
-"If the function inserts no characters, it calls setstate(failbit)
-(which
-may throw ios_base::failure (27.4.4.3)). If an exception was thrown
-while extracting a character, the function sets failbit in error
-state,
-and if failbit is on in exceptions() the caught exception is
-rethrown."
-
    
 
-
    
-The sentence starting with "If an exception was thrown" seems to
-imply that such an exception *should* be caught before.
-
    
 
 
-
    Proposed resolution:
    
+
+
    
+
    568. log2 overloads missing
    
+
    Section: TR1 8.16.4 [tr.c99.cmath.over] Status: NAD
+ Submitter: Paolo Carlini Opened: 2006-03-07  Last modified: 2009-07-13
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
    
-(a) In 27.7.1.2.3 [istream::extractors]/15 (N2134) change the sentence
+log2 is missing from the list of "additional overloads" in TR1 8.16.4 [tr.c99.cmath.over] p1.
 
    
 
-
    
-If the function inserts no characters, it calls
-setstate(failbit), which may throw ios_base::failure
-(27.4.4.3). If it inserted no characters because it caught an
-exception thrown while extracting characters from *this
-an exception was thrown while extracting a character from
-*this, the function sets failbit in error state,
-and failbit is on in exceptions() (27.4.4.3), then the
-caught exception is rethrown.
-
    
-
 
    
-(b) In 27.7.2.6.3 [ostream.inserters]/8 (N2134) change the sentence:
+Hinnant:  This is a TR1 issue only.  It is fixed in the current (N2135) WD.
 
    
 
+
    [
+Batavia (2009-05):
+]
    
+
 
    
-
    
-Gets characters from sb and inserts them in *this.
-Characters are read from sb and inserted until any of the
-following occurs:
-
    
-
      
-
    • end-of-file occurs on the input sequence;
      • 
-
    • inserting in the output sequence fails (in which case the character to be inserted is not extracted);
      • 
-
    • an exception occurs while getting a character from sb (in which
-case the exception is caught).
      • 
-
    
+We agree this has been fixed in the Working Draft.
+Move to NAD.
 
    
 
 
-
-
    Rationale:
    
-This extractor is described as a formatted input function so the
-exception behavior is already specified. There is additional behavior
-described in this section that applies to the case in which failbit is
-set. This doesn't contradict the usual exception behavior for formatted
-input functions because that applies to the case in which badbit is set.
+
    Proposed resolution:
    
+
    
+Add log2 to the list of functions in TR1 8.16.4 [tr.c99.cmath.over] p1.
+
    
 
 
 
 
 
 
    
-
    641. Editorial fix for 27.6.4 (N2134)
    
-
    Section: 27.7.4 [ext.manip] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2007-02-18  Last modified: 2007-07-02
    
-
    View all other issues in [ext.manip].
    
-
    View all issues with NAD Editorial status.
    
+
    569. Postcondition for basic_ios::clear(iostate) incorrectly stated
    
+
    Section: 27.5.4.3 [iostate.flags] Status: Dup
+ Submitter: Seungbeom Kim Opened: 2006-03-10  Last modified: 2006-12-30
    
+
    View all other issues in [iostate.flags].
    
+
    View all issues with Dup status.
    
+
    Duplicate of: 272
    
 
    Discussion:
    
 
    
-The function f in para 4 (27.7.4 [ext.manip]) references an unknown strm
-in the following line:
+Section: 27.4.4.3 [lib.iostate.flags]
 
    
-
-
    mg.get(Iter(str.rdbuf()), Iter(), intl, strm, err, mon);
+
    
+Paragraph 4 says:
+
    
+
    
+
    void clear(iostate state = goodbit);
 
    
+
    
+Postcondition: If rdbuf()!=0 then state == rdstate();
+otherwise rdstate()==state|ios_base::badbit.
+
    
+
    
 
-
-
    Proposed resolution:
    
 
    
-Change 27.7.4 [ext.manip], p4:
+The postcondition "rdstate()==state|ios_base::badbit" is parsed as
+"(rdstate()==state)|ios_base::badbit", which is probably what the
+committee meant.
 
    
 
-
    mg.get(Iter(str.rdbuf()), Iter(), intl, strm, err, mon);
-
    
 
-
    [
-Oxford:  Editorial.
-]
    
 
 
+
    Rationale:
    
+
 
 
 
 
 
 
    
-
    642. Invalidated fstream footnotes in N2134
    
-
    Section: 27.9.1.9 [ifstream.members], 27.9.1.13 [ofstream.members] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2007-02-20  Last modified: 2007-07-02
    
-
    View all other issues in [ifstream.members].
    
-
    View all issues with NAD Editorial status.
    
+
    570. Request adding additional explicit specializations of char_traits
    
+
    Section: 21.2 [char.traits] Status: NAD
+ Submitter: Jack Reeves Opened: 2006-04-06  Last modified: 2008-06-18
    
+
    View all other issues in [char.traits].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-The standard wording of N2134 has extended the 14882:2003(E)
-wording for the ifstream/ofstream/fstream open function to fix
-a long standing problem, see 409.
+Currently, the Standard Library specifies only a declaration for template class
+char_traits<> and requires the implementation provide two explicit
+specializations: char_traits<char> and char_traits<wchar_t>. I feel the Standard
+should require explicit specializations for all built-in character types, i.e.
+char, wchar_t, unsigned char, and signed char.
 
    
-
 
    
-Now it's properly written as
+I have put together a paper
+(N1985)
+that describes this in more detail and
+includes all the necessary wording.
 
    
+
    [
+Portland: Jack will rewrite
+N1985
+to propose a primary template that will work with other integral types.
+]
    
 
-
    
-"If that function does not return a null pointer calls clear(),
-otherwise
-calls setstate(failbit)[..]"
-
    
+
    [
+Toronto: issue has grown with addition of char16_t and char32_t.
+]
    
 
-
    
-instead of the previous
-
    
 
-
    
-"If that function returns a null pointer, calls setstate(failbit)[..]
-
    
+
    [
+post Bellevue:
+]
    
 
+
+
    
 
    
-While the old footnotes saying
+We suggest that Jack be asked about the status of his paper, and if it
+is not forthcoming, the work-item be assigned to someone else. If no one
+steps forward to do the paper before the next meeting, we propose to
+make this NAD without further discussion. We leave this Open for now,
+but our recommendation is NAD.
 
    
-
-
    
-"A successful open does not change the error state."
-
    
-
 
    
-where correct and important, they are invalid now for ifstream and
-ofstream (because clear *does* indeed modify the error state) and
-should be removed (Interestingly fstream itself never had these,
-although
-they where needed for that time).
+Note: the issue statement should be updated, as the Toronto comment has
+already been resolved. E.g., char_traits specializations for char16_t
+and char32_t are now in the working paper.
 
    
+
    
+
+
    [
+Sophia Antipolis:
+]
    
+
+
+
    
+Nobody has submitted the requested paper, so we move to NAD, as suggested by the decision at the last meeting.
+
    
 
 
 
    Proposed resolution:
    
+
+
+
+
+
+
    
+
    571. Update C90 references to C99?
    
+
    Section: 1.2 [intro.refs] Status: NAD Editorial
+ Submitter: Beman Dawes Opened: 2006-04-08  Last modified: 2007-07-02
    
+
    View all other issues in [intro.refs].
    
+
    View all issues with NAD Editorial status.
    
+
    Discussion:
    
 
    
-In 27.9.1.9 [ifstream.members], remove footnote:
+1.2 Normative references [intro.refs] of the WP currently refers to ISO/IEC
+9899:1990, Programming languages - C. Should that be changed to ISO/IEC
+9899:1999?
+
    
+
    
+What impact does this have on the library?
 
    
 
-
    
-334) A successful open does not change the error state.
-
    
 
+
    Proposed resolution:
    
 
    
-In 27.9.1.13 [ofstream.members], remove footnote:
+In 1.2/1 [intro.refs] of the WP, change:
 
    
+
    
+
      
+
    • ISO/IEC 9899:19901999 + TC1 + TC2, Programming languages - C
      • 
+
    
+
    
 
-
    
-335) A successful open does not change the error state.
-
    
 
 
+
    Rationale:
    
+Recommend NAD, fixed editorially.
+
 
 
 
 
 
    
-
    645. Missing members in match_results
    
-
    Section: 28.11 [re.results] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2007-02-26  Last modified: 2008-03-12
    
-
    View all other issues in [re.results].
    
-
    View all issues with NAD Editorial status.
    
+
    572. Oops, we gave 507 WP status
    
+
    Section: 26.5 [rand], TR1 5.1 [tr.rand] Status: NAD
+ Submitter: Howard Hinnant Opened: 2006-04-11  Last modified: 2007-04-18
    
+
    View all other issues in [rand].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-According to the description given in 28.11 [re.results]/2 the class template
-match_results "shall satisfy the requirements of a Sequence, [..],
-except that only operations defined for const-qualified Sequences
-are supported".
-Comparing the provided operations from 28.11 [re.results]/3 with the
-sequence/container tables 80 and 81 one recognizes the following
-missing operations:
+In Berlin, as a working group, we voted in favor of N1932 which makes issue 507 moot:
+variate_generator has been eliminated.  Then in full committee we voted to give
+this issue WP status (mistakenly).
 
    
 
+
+
    Proposed resolution:
    
 
    
-1) The members
+Strike the proposed resolution of issue 507.
 
    
+
    [
+post-Portland:  Walter and Howard recommend NAD.  The proposed resolution of 507 no longer
+exists in the current WD.
+]
    
 
-
    const_iterator rbegin() const;
-const_iterator rend() const;
-
    
 
+
+
    Rationale:
    
 
    
-should exists because 23.1/10 demands these for containers
-(all sequences are containers) which support bidirectional
-iterators. Aren't these supported by match_result? This is not
-explicitely expressed, but it's somewhat implied by two arguments:
-
    
-
    
-(a) Several typedefs delegate to
-iterator_traits<BidirectionalIterator>.
+NAD.  Will be moot once
+N2135
+is adopted.
 
    
+
+
+
+
+
+
    
+
    573. C++0x file positioning should handle modern file sizes
    
+
    Section: 27.5.3 [fpos] Status: NAD
+ Submitter: Beman Dawes Opened: 2006-04-12  Last modified: 2009-07-15
    
+
    View all other issues in [fpos].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
    
-(b) The existence of const_reference operator[](size_type n) const
-implies even random-access iteration.
-I also suggest, that match_result should explicitly mention,
-which minimum iterator category is supported and if this does
-not include random-access the existence of operator[] is
-somewhat questionable.
+There are two deficiencies related to file sizes:
 
    
+
      
+
    1. It doesn't appear that the Standard Library is specified in
+      a way that handles modern file sizes, which are often too
+      large to be represented by an unsigned long.
      2. 
+
+
    2. The std::fpos class does not currently have the ability to
+      set/get file positions.
      3. 
+
    
 
    
-2) The new "convenience" members
+The Dinkumware implementation of the Standard Library as shipped with the Microsoft compiler copes with these issues by:
 
    
-
    const_iterator cbegin() const;
-const_iterator cend() const;
-const_iterator crbegin() const;
-const_iterator crend() const;
+
      
+
    1. Defining fpos_t be long long, which is large enough to
+      represent any file position likely in the foreseeable future.
      2. 
+
+
    2. Adding member functions to class fpos. For example,
+
      fpos_t seekpos() const;
 
      
+
      3. 
+
    
 
    
-should be added according to tables 80/81.
+Because there are so many types relating to file positions and offsets (fpos_t,
+fpos, pos_type, off_type, streamoff, streamsize, streampos, wstreampos, and
+perhaps more), it is difficult to know if the Dinkumware extensions are
+sufficient. But they seem a useful starting place for discussions, and they do
+represent existing practice.
 
    
 
+
    [
+Kona (2007): We need a paper. It would be nice if someone proposed
+clarifications to the definitions of pos_type and off_type. Currently
+these definitions are horrible. Proposed Disposition: Open
+]
    
 
-
    Proposed resolution:
    
-
    
-Add the following members to the match_results synopsis after end() in 28.11 [re.results]
-para 3:
-
    
 
-
    const_iterator cbegin() const; 
-const_iterator cend() const;
-
    
+
    [
+2009-07 Frankfurt
+]
    
 
-
    
-In section 28.11.3 [re.results.acc] change:
-
    
 
 
    
-
    const_iterator begin() const;
-const_iterator cbegin() const;
-
    
-
    
 
    
--7- Returns: A starting iterator that enumerates over all the sub-expressions stored in *this.
+This is the subject of paper N2926.
 
    
-
    
-
-
    const_iterator end() const;
-const_iterator cend() const;
-
    
-
    
 
    
--8- Returns: A terminating iterator that enumerates over all the sub-expressions stored in *this.
+If we choose to take any action, we will move the paper, so the issue can be closed.
+
    
+
    
+Move to NAD.
 
    
 
    
-
    
-
 
 
-
    [
-Kona (2007): Voted to adopt proposed wording in
-N2409
-except removing the entry in the table container requirements.  Moved to Review.
-]
    
-
 
-
    [
-Bellevue:  Proposed wording now in the WP.
-]
    
+
    Proposed resolution:
    
+
    
+
    
 
 
 
 
 
 
    
-
    647. Inconsistent regex_search params
    
-
    Section: 28.12.3 [re.alg.search] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2007-02-26  Last modified: 2007-07-26
    
-
    View all issues with NAD Editorial status.
    
+
    579. erase(iterator) for unordered containers should not return an iterator
    
+
    Section: 23.2.5 [unord.req] Status: NAD
+ Submitter: Joaquín M López Muñoz Opened: 2006-06-13  Last modified: 2008-03-12
    
+
    View other active issues in [unord.req].
    
+
    View all other issues in [unord.req].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-28.12.3 [re.alg.search]/5 declares
+See
+N2023
+for full discussion.
 
    
 
-
    template <class iterator, class charT, class traits>
-bool regex_search(iterator first, iterator last,
-                  const basic_regex<charT, traits>& e,
-                  regex_constants::match_flag_type flags =
-                      regex_constants::match_default);
-
    
 
+
    Proposed resolution:
    
 
    
-where it's not explained, which iterator category
-the parameter iterator belongs to. This is inconsistent
-to the preceding declaration in the synopsis section
-28.5 [re.syn], which says:
+Option 1:
 
    
 
-
    template <class BidirectionalIterator, class charT, class traits>
-bool regex_search(BidirectionalIterator first, BidirectionalIterator last,
-                  const basic_regex<charT, traits>& e,
-                  regex_constants::match_flag_type flags =
-                      regex_constants::match_default);
-
    
-
+
    
+The problem can be eliminated by omitting the requirement that a.erase(q) return an 
+iterator. This is, however, in contrast with the equivalent requirements for other 
+standard containers.
+
    
 
-
    Proposed resolution:
    
 
    
-In 28.12.3 [re.alg.search]/5 replace all three occurences of param "iterator" with
-"BidirectionalIterator"
+Option 2:
 
    
 
-
    template <class iterator BidirectionalIterator, class charT, class traits>
-  bool regex_search(iterator BidirectionalIterator first, iterator BidirectionalIterator last, 
-                    const basic_regex<charT, traits>& e, 
-                    regex_constants::match_flag_type flags = 
-                      regex_constants::match_default);
-
    
 
    
--6- Effects: Behaves "as if" by constructing an object what of
-type match_results<iterator
-BidirectionalIterator> and then returning the result
-of regex_search(first, last, what, e, flags).
+a.erase(q) can be made to compute the next iterator only when explicitly requested: 
+the technique consists in returning a proxy object implicitly convertible to iterator, so 
+that
 
    
-
    
+
+
    iterator q1=a.erase(q);
+
    
+
+
    
+works as expected, while
+
    
+
+
    a.erase(q);
+
    
+
+
    
+does not ever invoke the conversion-to-iterator operator, thus avoiding the associated 
+computation. To allow this technique, some sections of TR1 along the line "return value 
+is an iterator..." should be changed to "return value is an unspecified object implicitly 
+convertible to an iterator..." Although this trick is expected to work transparently, it can 
+have some collateral effects when the expression a.erase(q) is used inside generic 
+code.
+
    
+
 
 
 
    Rationale:
    
-Applied to working paper while issue was still in New status.
+
    
+N2023
+was discussed in Portland and the consensus was that there appears to be
+no need for either change proposed in the paper.  The consensus opinion
+was that since the iterator could serve as its own proxy, there appears
+to be no need for the change. In general, "converts to" is undesirable
+because it interferes with template matching.
+
    
+
+
    
+Post Toronto:  There does not at this time appear to be consensus with the Portland consensus. 
+
    
+
+
    [
+Bellevue:
+]
    
+
+
+
    
+The Bellevue review of this issue reached consensus with the Portland
+consensus, in contravention of the Toronto non-consensus. Common
+implementations have the iterator readily available, and most common
+uses depend on the iterator being returned.
+
    
+
 
 
 
 
 
 
    
-
    648. regex_iterator c'tor needs clarification/editorial fix
    
-
    Section: 28.13.1.1 [re.regiter.cnstr] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2007-03-03  Last modified: 2007-07-02
    
-
    View all issues with NAD Editorial status.
    
+
    582. specialized algorithms and volatile storage
    
+
    Section: 20.8.8.2 [uninitialized.copy] Status: NAD
+ Submitter: Martin Sebor Opened: 2006-06-14  Last modified: 2009-07-15
    
+
    View all other issues in [uninitialized.copy].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
+
+
    Related to 1029
    
+        
    
+
+The specialized  algorithms [lib.specialized.algorithms] are specified
+as having the general effect of invoking the following expression:
+
+        
    
+            
    +new (static_cast<void*>(&*i))
+    typename iterator_traits<ForwardIterator>::value_type (x)
+
+            
    
+        
    
+
+This  expression is  ill-formed  when the  type  of the  subexpression
+&*i is some volatile-qualified T.
+
+        
    
+
+
    [
+Batavia:  Lack of support for proposed resolution but agree there is a
+defect.  Howard to look at wording.  Concern that move semantics
+properly expressed if iterator returns rvalue.
+]
    
+
+
+
+
    [
+2009-06-17 Pablo adds:
+]
    
+
+
+
    
+
+
    Propose that Issue 582 be closed NAD.
    
 
    
-In 28.13.1.1 [re.regiter.cnstr]/2 the effects paragraph starts with:
+Issue 582 asks that uninitialized_copy,
+uninitialized_fill, and uninitialized_fill_n should be
+well-formed if the result type is volatile.  My feeling is that the
+standard does not, and should not, guarantee any useful behavior when
+constructors are invoked on volatile storage, so making it syntactically
+legal to call uninitialized_copy on volatile storage is not useful. A
+possible editorial change would be to put my previous sentence into a
+non-normative note.
 
    
-
+
    
+Note that the three sections starting with 20.8.8.2 [uninitialized.copy] do not
+yet have concepts.  Here's a first crack at the first one:
+
    
+
    template <InputIterator InIter, OutputIterator OutIter>
+requires ExplicitConvertible<HasDereference<OutIter::reference>::result,
+                             OutIter::value_type&>
+      && Convertible<OutIter::value_type*, void*>
+      && ExplicitConvertible<OutIter::value_type, InIter::reference>
+  OutIter uninitialized_copy(InIter first, InIter last, OutIter result);
+
    
 
    
 
    
-Effects: Initializes begin and end to point to the beginning and the
-end of the target sequence, sets pregex to &re, sets flags to f,[..]
-
    
+Effects:
+
    
+
    while (first != last) {
+  typedef OutIter::value_type value_type;
+  value_type& outRef = static_cast<value_type&>(*result++);
+  ::new (static_cast<void*>(addressof(outRef))) value_type(*first++);
+}
+
    
+
    
+
+
    
 
 
    
-There are two issues with this description:
+Notes:
 
    
-
 
      
+
    1. This definition is actually LESS constrained than in C++03 because
+there is no requirement that the result be a forward iterator.
+
      2. 
 
    2. 
-The meaning of very first part of this quote is unclear, because
-there is no target sequence provided, instead there are given two
-parameters a and b, both of type BidirectionalIterator. The mentioned
-part does not explain what a and b represent.
+If
+OutIter returns a proxy type with an overloaded operator&, this
+definition probably won't compile.  Lifting this limitation while
+allowing value_type to have an overloaded operator& would be hard, but
+is probably possible with careful overloading.  I'm not sure it's worth
+it.
 
      3. 
 
    3. 
-There does not exist any parameter f, but instead a parameter
-m in the constructor declaration, so this is actually an editorial
-fix.
+This definition retains the prohibition on the use of volatile types for the result.
 
      4. 
 
    
 
+
    
 
-
    Proposed resolution:
    
-
    
-In 28.13.1.1 [re.regiter.cnstr]/2 change the above quoted part by
-
    
-
-
    
-Effects: Initializes begin and end to point to
-the beginning and the end of the target sequence designated by the
-iterator range [a, b), sets pregex to
-&re, sets flags to f
-m, then calls regex_search(begin, end, match,
-*pregex, flags). If this call returns false the
-constructor sets *this to the end-of-sequence iterator.
-
    
-
-
-
+
    [
+2009-07 Frankfurt
+]
    
 
 
-
    
-
    649. Several typos in regex_token_iterator constructors
    
-
    Section: 28.13.2.1 [re.tokiter.cnstr] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2007-03-03  Last modified: 2007-07-02
    
-
    View all other issues in [re.tokiter.cnstr].
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
+
    
 
    
-In 28.13.2.1 [re.tokiter.cnstr]/1+2 both the constructor declaration
-and the following text shows some obvious typos:
+We don't deal with volatile in the library.
 
    
 
    
-1) The third constructor form is written as
+Jim: should we state that explicitly somewhere?
 
    
-
    template <std::size_t N>
-  regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b, 
-                       const regex_type& re, 
-                       const int (&submatches)[R], 
-                       regex_constants::match_flag_type m = 
-                         regex_constants::match_default);
-
    
-
 
    
-where the dimensions of submatches are specified by an
-unknown value R, which should be N.
+Beman: you might argue that clause 17 should say something about
+volatile. However, if you want to raise we argument, we should open it
+as a separate issue and consult with experts on concurrency.
 
    
 
    
-2) Paragraph 2 of the same section says in its last sentence:
+Hinnant: actually, some library components do handle volatile, so we'd
+need to be very careful about what we say in clause 17.
 
    
-
-
    
-The third constructor initializes the member subs to hold a
-copy of the sequence of integer values pointed to by the iterator range
-[&submatches, &submatches + R).
-
    
-
 
    
-where again R must be replaced by N.
+No objection to NAD.
 
    
-
 
    
-3) Paragraph 3 of the same section says in its first sentence:
+Move to NAD.
 
    
+
    
 
-
    
-Each constructor then sets N to 0, and
-position to position_iterator(a, b, re, f).
-
    
+    
 
-
    
-where a non-existing parameter "f" is mentioned, which must be
-replaced
-by the parameter "m".
-
    
+    
    Proposed resolution:
    
+        
    
 
+In order  to allow these algorithms  to operate on  volatile storage I
+propose to change the expression so as to make it well-formed even for
+pointers  to volatile  types.  Specifically,  I propose  the following
+changes to clauses 20 and 24. Change 20.6.4.1, p1 to read:
 
-
    Proposed resolution:
    
-
    
-Change 28.13.2.1 [re.tokiter.cnstr]/1:
-
    
-
    template <std::size_t N>
-  regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b, 
-                       const regex_type& re, 
-                       const int (&submatches)[R N], 
-                       regex_constants::match_flag_type m = 
-                         regex_constants::match_default);
-
    
+        
    
+            
    +Effects:
 
-
    
-Change 28.13.2.1 [re.tokiter.cnstr]/2:
-
    
+typedef typename iterator_traits<ForwardIterator>::pointer    pointer;
+typedef typename iterator_traits<ForwardIterator>::value_type value_type;
 
-
    
-Effects: The first constructor initializes the member
-subs to hold the single value submatch. The second
-constructor initializes the member subs to hold a copy of the
-argument submatches. The third constructor initializes the
-member subs to hold a copy of the sequence of integer values
-pointed to by the iterator range [&submatches, &submatches +
-R N).
-
    
+for (; first != last; ++result, ++first)
+    new (static_cast<void*>(const_cast<pointer>(&*result))
+        value_type (*first);
 
-
    
-Change 28.13.2.1 [re.tokiter.cnstr]/3:
-
    
+            
    
+        
    
 
-
    
-Each constructor then sets N to 0, and
-position to position_iterator(a, b, re, f
-m). If position is not an end-of-sequence
-iterator the constructor sets result to the address of the
-current match. Otherwise if any of the values stored in subs is
-equal to -1 the constructor sets *this to a suffix
-iterator that points to the range [a, b), otherwise the
-constructor sets *this to an end-of-sequence iterator.
-
    
+change 20.6.4.2, p1 to read
+
+        
    
+            
    +Effects:
+
+typedef typename iterator_traits<ForwardIterator>::pointer    pointer;
+typedef typename iterator_traits<ForwardIterator>::value_type value_type;
+
+for (; first != last; ++result, ++first)
+    new (static_cast<void*>(const_cast<pointer>(&*first))
+        value_type (*x);
+
+            
    
+        
    
+
+and change 20.6.4.3, p1 to read
+
+        
    
+            
    +Effects:
+
+typedef typename iterator_traits<ForwardIterator>::pointer    pointer;
+typedef typename iterator_traits<ForwardIterator>::value_type value_type;
+
+for (; n--; ++first)
+    new (static_cast<void*>(const_cast<pointer>(&*first))
+        value_type (*x);
+
+            
    
+        
    
+
+In   addition,  since   there   is  no   partial  specialization   for
+iterator_traits<volatile T*>  I propose to  add one
+to parallel such specialization  for <const T*>. Specifically, I
+propose to add the following text to the end of 24.3.1, p3:
+
+        
    
+        
    
+
+and for pointers to volatile as 
+
+        
    
+            
    +namespace std {
+template<class T> struct iterator_traits<volatile T*> {
+typedef ptrdiff_t difference_type;
+typedef T value_type;
+typedef volatile T* pointer;
+typedef volatile T& reference;
+typedef random_access_iterator_tag iterator_category;
+};
+}
 
+            
    
+        
    
 
+Note that  the change to  iterator_traits isn't necessary
+in order to implement the  specialized algorithms in a way that allows
+them to operate on volatile  strorage. It is only necesassary in order
+to specify  their effects in terms  of iterator_traits as
+is  done here.   Implementations can  (and some  do) achieve  the same
+effect by means of function template overloading.
 
+        
    
+    
 
 
 
 
    
-
    653. Library reserved names
    
-
    Section: 1.2 [intro.refs] Status: NAD
- Submitter: Alisdair Meredith Opened: 2007-03-08  Last modified: 2008-02-25
    
-
    View all other issues in [intro.refs].
    
+
    583. div() for unsigned integral types
    
+
    Section: 26.8 [c.math] Status: NAD
+ Submitter: Beman Dawes Opened: 2006-06-15  Last modified: 2007-07-25
    
+
    View all other issues in [c.math].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
+There is no div() function for unsigned integer types.
 
    
-
    
 
    
-1.2 [intro.refs] Normative references
+There are several possible resolutions.  The simplest one is noted below.  Other
+possibilities include a templated solution.
 
    
 
+
+
    Proposed resolution:
    
 
    
-The following standards contain provisions which, through reference in
-this text, constitute provisions of this Interna- tional Standard. At
-the time of publication, the editions indicated were valid. All
-standards are subject to revision, and parties to agreements based on
-this International Standard are encouraged to investigate the
-possibility of applying the most recent editions of the standards
-indicated below. Members of IEC and ISO maintain registers of currently
-valid International Standards.
+Add to 26.7 [lib.c.math] paragraph 8:
 
    
 
-
      
-
    • Ecma International, ECMAScript Language Specification, Standard
-Ecma-262, third edition, 1999.
      • 
-
    • ISO/IEC 2382 (all parts), Information technology - Vocabulary
      • 
-
    • ISO/IEC 9899:1990, Programming languages - C
      • 
-
    • ISO/IEC 9899/Amd.1:1995, Programming languages - C, AMENDMENT 1: C
-Integrity
      • 
-
    • ISO/IEC 9899:1999, Programming languages - C
      • 
-
    • ISO/IEC 9899:1999/Cor.1:2001 Programming languages - C
      • 
-
    • ISO/IEC 9899:1999/Cor.2:2004 Programming languages - C
      • 
-
    • ISO/IEC 9945:2003, Information Technology-Portable Operating System
-Interface (POSIX)
      • 
-
    • ISO/IEC 10646-1:1993 Information technology - Universal Multiple-Octet
-Coded Character Set (UCS) - Part 1: Architecture and Basic Multilingual
-Plane
      • 
-
    
-
    
+
    struct udiv_t div(unsigned, unsigned);
+struct uldiv_t div(unsigned long, unsigned long);
+struct ulldiv_t div(unsigned long long, unsigned long long);
+
    
 
+
+
+
    Rationale:
    
+Toronto:  C99 does not have these unsigned versions because
+the signed version exist just to define the implementation-defined behavior
+of signed integer division.  Unsigned integer division has no implementation-defined
+behavior and thus does not need this treatment.
+
+
+
+
+
+
    
+
    584. missing int pow(int,int) functionality
    
+
    Section: 26.8 [c.math] Status: NAD
+ Submitter: Beman Dawes Opened: 2006-06-15  Last modified: 2007-07-25
    
+
    View all other issues in [c.math].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
    
-I'm not sure how many of those reserve naming patterns that might affect
-us, but I am equally sure I don't own a copy of any of these to check!
+There is no pow() function for any integral type.
 
    
+
+
+
    Proposed resolution:
    
 
    
-The point is to list the reserved naming patterns, rather than the
-individual names themselves - although we may want to list C keywords
-that are valid identifiers in C++ but likely to cause trouble in shared
-headers (e.g. restrict)
+Add something like:
 
    
 
-
    [
-Kona (2007): Recommend NAD.  No one has identified a specific defect, just the possibility of one.
-]
    
+
    template< typename T>
+T power( T x, int n );
+// requires: n >=0
+
    
 
 
-
    [
-Post-Kona: Alisdair request Open. A good example of the problem was a
-discussion of the system error proposal, where it was pointed out an all-caps
-identifier starting with a capital E conflicted with reserved macro names for
-both Posix and C.  I had absolutely no idea of this rule, and suspect I was
-not the only one in the room.
    
-
    
-Resolution will require someone with access to all the listed documents to
-research their respective name reservation rules, or people with access to
-specific documents add their rules to this issue until the list is complete.
-]
    
+
    Rationale:
    
+Toronto:  We already have double pow(integral, integral) from 26.8 [c.math] p11.
+
+
+
+
+
+
    
+
    585. facet error reporting
    
+
    Section: 22.4 [locale.categories] Status: NAD
+ Submitter: Martin Sebor, Paolo Carlini Opened: 2006-06-22  Last modified: 2009-07-15
    
+
    View all other issues in [locale.categories].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+        
    
+
+Section  22.2, paragraph 2  requires facet  get() members
+that    take    an    ios_base::iostate&    argument,
+err,  to   ignore  the  (initial)   value  of  the
+argument, but to set it to ios_base::failbit in case of a
+parse error.
+
+        
    
+        
    
+
+We  believe  there  are  a   few  minor  problems  with  this  blanket
+requirement  in   conjunction  with   the  wording  specific   to  each
+get() member function.
+
+        
    
+        
    
+
+First,  besides get()  there are  other  member functions
+with     a      slightly     different     name      (for     example,
+get_date()). It's not completely clear that the intent of
+the  paragraph  is  to  include  those  as  well,  and  at  least  one
+implementation has interpreted the requirement literally.
+
+        
    
+        
    
+
+Second,    the     requirement    to    "set     the    argument    to
+ios_base::failbit  suggests that  the  functions are  not
+permitted    to   set    it   to    any   other    value    (such   as
+ios_base::eofbit,   or   even  ios_base::eofbit   |
+ios_base::failbit).
+
+        
    
+        
    
+
+However, 22.2.2.1.2, p5 (Stage  3 of num_get parsing) and
+p6 (bool parsing)  specifies that the do_get
+functions  perform err |=  ios_base::eofbit, which
+contradicts  the earlier  requirement to  ignore  err's initial
+value.
+
+        
    
+        
    
 
+22.2.6.1.2,  p1  (the  Effects  clause of  the  money_get
+facet's  do_get  member  functions) also  specifies  that
+err's initial  value be used to  compute the final
+value  by  ORing  it  with  either  ios_base::failbit  or
+withios_base::eofbit | ios_base::failbit.
+
+        
    
 
 
    [
-Bellevue: Wording is aleady present in various standards, and no-one has come forward with wording.
-Suggest a formal paper rather than a defect report is the correct way to proceed.
+2009-07 Frankfurt
 ]
    
 
 
+
    
+Move to NAD.
+
    
+
+    
+
+    
    Proposed resolution:
    
+        
    
+
+We believe the  intent is for all facet member  functions that take an
+ios_base::iostate& argument to:
 
+        
    
+            
      
+                
    • 
 
-
      Proposed resolution:
      
+ignore the initial value of the err argument,
 
+                
      • 
+                
    • 
+
+reset err  to ios_base::goodbit prior
+to any further processing,
+
+                
      • 
+                
    • 
+
+and       set      either       ios_base::eofbit,      or
+ios_base::failbit, or both in err, as
+appropriate,  in response  to  reaching the  end-of-file  or on  parse
+error, or both.
+
+                
      • 
+            
    
+        
    
+
+To that effect we propose to change 22.2, p2 as follows:
+
+        
    
+        
    
+
+The  put()  members  make  no  provision  for  error
+reporting.   (Any  failures of  the  OutputIterator  argument must  be
+extracted   from  the   returned  iterator.)    Unless  otherwise
+specified, the get()  members  that
+take an  ios_base::iostate& argument whose value
+they  ignore,  but  set  to  ios_base::failbit  in  case  of  a  parse
+error.,   err,   start  by   evaluating
+err  =   ios_base::goodbit,  and  may   subsequently  set
+err     to     either     ios_base::eofbit,     or
+ios_base::failbit,     or     ios_base::eofbit    |
+ios_base::failbit in response to reaching the end-of-file or in
+case of a parse error, or both, respectively.
+
+        
    
+    
+    
+
    [
+Kona (2007): We need to change the proposed wording to clarify that the
+phrase "the get members" actually denotes get(), get_date(), etc.
+Proposed Disposition: Open
+]
    
 
 
 
 
 
    
-
    656. Typo in subtract_with_carry_engine declaration
    
-
    Section: 26.5.1 [rand.synopsis] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2007-03-08  Last modified: 2007-07-02
    
-
    View all other issues in [rand.synopsis].
    
+
    587. iststream ctor missing description
    
+
    Section: D.7.2.1 [depr.istrstream.cons] Status: NAD Editorial
+ Submitter: Martin Sebor Opened: 2006-06-22  Last modified: 2007-05-11
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
-
    
-26.5.1 [rand.synopsis] the header <random> synopsis
-contains an unreasonable closing curly brace inside the
-subtract_with_carry_engine declaration.
-
    
+        
    
+
+The  iststream(char*, streamsize)  ctor is  in  the class
+synopsis  in D.7.2  but its  signature is  missing in  the description
+below (in D.7.2.1).
 
+        
    
+    
 
-
    Proposed resolution:
    
-
    
-Change the current declaration in 26.5.1 [rand.synopsis]
-
    
+    
    Proposed resolution:
    
+        
    
 
-
    template <class UIntType, size_t w}, size_t s, size_t r>
-class subtract_with_carry_engine;
-
    
+This seems like a simple editorial issue and the missing signature can
+be added to the one for const char* in paragraph 2.
 
+        
    
 
 
    [
-Pete: Recommends editorial.
+post Oxford: Noted that it is already fixed in
+N2284
 ]
    
 
 
+    
 
 
 
 
    
-
    657. unclear requirement about header inclusion
    
-
    Section: 17.6.2.2 [using.headers] Status: NAD
- Submitter: Gennaro Prota Opened: 2007-03-14  Last modified: 2007-10-10
    
-
    View all issues with NAD status.
    
+
    590. Type traits implementation latitude should be removed for C++0x
    
+
    Section: 20.6 [meta], TR1 4.9 [tr.meta.req] Status: NAD Editorial
+ Submitter: Beman Dawes Opened: 2006-08-10  Last modified: 2007-05-11
    
+
    View other active issues in [meta].
    
+
    View all other issues in [meta].
    
+
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-17.6.2.2 [using.headers] states:
+20.4.9 [lib.meta.req], Implementation requirements, provides latitude for type
+traits implementers that is not needed in C++0x. It includes the wording:
 
    
 
 
    
-A translation unit shall include a header only outside of any
-external declaration or definition, [...]
+[Note: the latitude granted to implementers in this clause is temporary,
+and is expected to be removed in future revisions of this document. -- end note]
 
    
 
 
    
-I see three problems with this requirement:
-
    
-
-
      
-
    1. The C++ standard doesn't define what an "external declaration" or
-an "external definition" are (incidentally the C99 standard does, and
-has a sentence very similar to the above regarding header inclusion).
-
      
-I think the intent is that the #include directive shall lexically
-appear outside *any* declaration; instead, when the issue was pointed
-out on comp.std.c++ at least one poster interpreted "external
-declaration" as "declaration of an identifier with external linkage".
-If this were the correct interpretation, then the two inclusions below
-would be legal:
-
      
-
        // at global scope
-  static void f()
-  {
-# include <cstddef>
-  }
-
-  static void g()
-  {
-# include <stddef.h>
-  }
-
      
-
      
-(note that while the first example is unlikely to compile correctly,
-the second one may well do)
-
      2. 
-
-
    2. as the sentence stands, violations will require a diagnostic; is
-this the intent? It was pointed out on comp.std.c++ (by several
-posters) that at least one way to ensure a diagnostic exists:
+Note:
+N2157: Minor Modifications to the type traits Wording
+also has the intent of removing this wording from the WP.
 
      
-
      
-   [If there is an actual file for each header,] one simple way
-   to implement this would be to insert a reserved identifier
-   such as __begin_header  at the start of each standard header.
-   This reserved identifier would be ignored for all other
-   purposes, except that, at the appropriate point in phase 7, if
-   it is found inside an external definition, a diagnostic is
-   generated. There's many other similar ways to achieve the same
-   effect.
-   
      
-
                                       --James Kuyper, on comp.std.c++
-
      3. 
 
-
    3. is the term "header" meant to be limited to standard headers?
-Clause 17 is all about the library, but still the general question is
-interesting and affects one of the points in the explicit namespaces
-proposal (n1691):
-
      
-
      
-    Those seeking to conveniently enable argument-dependent
-    lookups for all operators within an explicit namespace
-    could easily create a header file that does so:
-
          namespace mymath::
-    {
-        #include "using_ops.hpp"
-    }
-
      
-
      4. 
-
    
 
 
 
    Proposed resolution:
    
 
    
+Remove 20.4.9 [lib.meta.req] in its entirety from the WP.
 
    
 
+
    [
+post-Oxford: Recommend NAD Editorial.  This resolution is now in the
+current working draft.
+]
    
+
 
-
    Rationale:
    
-We believe that the existing language does not cause any real confusion
-and any new formulation of the rules that we could come up with are
-unlikely to be better than what's already in the standard.
 
 
 
 
 
 
    
-
    658. Two unspecified function comparators in [function.objects]
    
-
    Section: 20.7 [function.objects] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2007-03-19  Last modified: 2007-08-05
    
-
    View all other issues in [function.objects].
    
+
    591. Misleading "built-in
    
+
    Section: 18.3.1.2 [numeric.limits.members] Status: NAD Editorial
+ Submitter: whyglinux Opened: 2006-08-08  Last modified: 2007-07-02
    
+
    View all other issues in [numeric.limits.members].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-The header <functional> synopsis in 20.7 [function.objects]
-contains the following two free comparison operator templates
-for the function class template
+18.2.1.2 numeric_limits members [lib.numeric.limits.members]
+Paragraph 7:
+
    
+
    
+"For built-in integer types, the number of non-sign bits in the
+representation."
+
    
+
+
    
+26.1 Numeric type requirements [lib.numeric.requirements]
+Footnote:
 
    
 
-
    template<class Function1, class Function2>
-void operator==(const function<Function1>&, const function<Function2>&);
-template<class Function1, class Function2>
-void operator!=(const function<Function1>&, const function<Function2>&);
-
    
+
    
+"In other words, value types. These include built-in arithmetic types,
+pointers, the library class complex, and instantiations of valarray for
+value types."
+
    
 
 
    
-which are nowhere described. I assume that they are relicts before the
-corresponding two private and undefined member templates in the function
-template (see 20.7.16.2 [func.wrap.func] and  [func.wrap.func.undef]) have been introduced. The original free
-function templates should be removed, because using an undefined entity
-would lead to an ODR violation of the user.
+Integer types (which are bool, char, wchar_t, and the signed and
+unsigned integer types) and arithmetic types (which are integer and
+floating types) are all built-in types and thus there are no
+non-built-in (that is, user-defined) integer or arithmetic types. Since
+the redundant "built-in" in the above 2 sentences can mislead that
+there may be built-in or user-defined integer and arithmetic types
+(which is not correct), the "built-in" should be removed.
 
    
 
 
 
    Proposed resolution:
    
 
    
-Remove the above mentioned two function templates from
-the header <functional> synopsis (20.7 [function.objects])
+18.2.1.2 numeric_limits members [lib.numeric.limits.members]
+Paragraph 7:
 
    
+
    
+"For built-in integer types, the number of non-sign bits in the
+representation."
+
    
 
-
    template<class Function1, class Function2>
-void operator==(const function<Function1>&, const function<Function2>&);
-template<class Function1, class Function2>
-void operator!=(const function<Function1>&, const function<Function2>&);
-
    
+
    
+26.1 Numeric type requirements [lib.numeric.requirements]
+Footnote:
+
    
 
+
    
+"In other words, value types. These include built-in arithmetic types,
+pointers, the library class complex, and instantiations of valarray for
+value types."
+
    
 
 
 
    Rationale:
    
-Fixed by
-N2292
-Standard Library Applications for Deleted Functions.
+
    
+Recommend NAD / Editorial.  The proposed resolution is accepted as editorial.
+
    
 
 
 
 
 
 
    
-
    662. Inconsistent handling of incorrectly-placed thousands separators
    
-
    Section: 22.4.2.1.2 [facet.num.get.virtuals] Status: NAD
- Submitter: Cosmin Truta Opened: 2007-04-05  Last modified: 2007-07-25
    
-
    View other active issues in [facet.num.get.virtuals].
    
-
    View all other issues in [facet.num.get.virtuals].
    
-
    View all issues with NAD status.
    
+
    592. Incorrect treatment of rdbuf()->close() return type
    
+
    Section: 27.9.1.9 [ifstream.members] Status: NAD Editorial
+ Submitter: Christopher Kohlhoff Opened: 2006-08-17  Last modified: 2008-07-02
    
+
    View all other issues in [ifstream.members].
    
+
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-From Section 22.4.2.1.2 [facet.num.get.virtuals], paragraphs 11 and 12, it is implied
-that the value read from a stream must be stored
-even if the placement of thousands separators does not conform to the
-grouping() specification from the numpunct facet.
-Since incorrectly-placed thousands separators are flagged as an extraction
-failure (by the means of failbit), we believe it is better not
-to store the value. A consistent strategy, in which any kind of extraction
-failure leaves the input item intact, is conceptually cleaner, is able to avoid
-corner-case traps, and is also more understandable from the programmer's point
-of view.
+I just spotted a minor problem in 27.8.1.7
+[lib.ifstream.members] para 4 and also 27.8.1.13
+[lib.fstream.members] para 4. In both places it says:
 
    
+
    
+
    void close();
+
    
 
    
-Here is a quote from "The C++ Programming Language (Special Edition)"
-by B. Stroustrup (Section D.4.2.3, pg. 897):
+Effects: Calls rdbuf()->close() and, if that function returns false, ...
 
    
-
    
-"If a value of the desired type could not be read, failbit is set in r.
-[...] An input operator will use r to determine how to set the state of its
-stream. If no error was encountered, the value read is assigned through v;
-otherwise, v is left unchanged."
-
    
+
    
 
    
-This statement implies that rdstate() alone is sufficient to
-determine whether an extracted value is to be assigned to the input item
-val passed to do_get. However, this is in disagreement
-with the current C++ Standard. The above-mentioned assumption is true in all
-cases, except when there are mismatches in digit grouping. In the latter case,
-the parsed value is assigned to val, and, at the same time, err
-is assigned to ios_base::failbit (essentially "lying" about the
-success of the operation). Is this intentional? The current behavior raises
-both consistency and usability concerns.
+However, basic_filebuf::close() (27.8.1.2) returns a pointer to the
+filebuf on success, null on failure, so I think it is meant to
+say "if that function returns a null pointer". Oddly, it is
+correct for basic_ofstream.
 
    
+
+
+
    Proposed resolution:
    
 
    
-Although digit grouping is outside the scope of scanf (on which
-the virtual methods of num_get are based), handling of grouping
-should be consistent with the overall behavior of scanf. The specification of
-scanf makes a distinction between input failures and matching
-failures, and yet both kinds of failures have no effect on the input items
-passed to scanf. A mismatch in digit grouping logically falls in
-the category of matching failures, and it would be more consistent, and less
-surprising to the user, to leave the input item intact whenever a failure is
-being signaled.
+Change 27.9.1.9 [ifstream.members], p5:
 
    
+
+
    
+Effects: Calls rdbuf()->close() and, if that function
+fails (returns false a null pointer),
+calls setstate(failbit) (which may throw ios_base::failure
+(27.4.4.3)).
+
    
+
 
    
-The extraction of bool is another example outside the scope of
-scanf, and yet consistent, even in the event of a successful
-extraction of a long but a failed conversion from
-long to bool.
+Change 27.9.1.17 [fstream.members], p5:
 
    
+
+
    
+Effects: Calls rdbuf()->close() and, if that function
+fails (returns false a null pointer),
+calls setstate(failbit) (which may throw ios_base::failure
+(27.4.4.3)).
+
    
+
+
+
+
    [
+Kona (2007): Proposed Disposition: NAD, Editorial
+]
    
+
+
+
+
+
+
    
+
    597. Decimal: The notion of 'promotion' cannot be emulated by user-defined types.
    
+
    Section: TRDecimal 3.2 [trdec.types.types] Status: NAD
+ Submitter: Daveed Vandevoorde Opened: 2006-04-05  Last modified: 2009-07-15
    
+
    View all other issues in [trdec.types.types].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
    
-Inconsistency is further aggravated by the fact that, when failbit is set,
-subsequent extraction operations are no-ops until failbit is
-explicitly cleared. Assuming that there is no explicit handling of
-rdstate() (as in cin>>i>>j) it is
-counter-intuitive to be able to extract an integer with mismatched digit
-grouping, but to be unable to extract another, properly-formatted integer
-that immediately follows.
+In a private email, Daveed writes:
 
    
+
    
 
    
-Moreover, setting failbit, and selectively assigning a value to
-the input item, raises usability problems. Either the strategy of
-scanf (when there is no extracted value in case of failure), or
-the strategy of the strtol family (when there is always an
-extracted value, and there are well-defined defaults in case of a failure) are
-easy to understand and easy to use. On the other hand, if failbit
-alone cannot consistently make a difference between a failed extraction, and a
-successful but not-quite-correct extraction whose output happens to be the same
-as the previous value, the programmer must resort to implementation tricks.
-Consider the following example:
+I am not familiar with the C TR, but my guess is that the
+class type approach still won't match a built-in type
+approach because the notion of "promotion" cannot be
+emulated by user-defined types.
 
    
-
        int i = old_i;
-    cin >> i;
-    if (cin.fail())
-        // can the value of i be trusted?
-        // what does it mean if i == old_i?
-        // ...
-
    
 
    
-Last but not least, the current behvaior is not only confusing to the casual
-reader, but it has also been confusing to some book authors. Besides
-Stroustrup's book, other books (e.g. "Standard C++ IOStreams and Locales" by
-Langer and Kreft) are describing the same mistaken assumption. Although books
-are not to be used instead of the standard reference, the readers of these
-books, as well as the people who are generally familiar to scanf,
-are even more likely to misinterpret the standard, and expect the input items
-to remain intact when a failure occurs.
+Here is an example:
 
    
+
    
+
    +         struct S {
+           S(_Decimal32 const&);  // Converting constructor
+         };
+         void f(S);
 
+         void f(_Decimal64);
 
-
    Proposed resolution:
    
+         void g(_Decimal32 d) {
+           f(d);
+         }
+
    
 
+
    
 
    
-Change 22.4.2.1.2 [facet.num.get.virtuals]:
+If _Decimal32 is a built-in type, the call f(d) will likely
+resolve to f(_Decimal64) because that requires only a
+promotion, whereas f(S) requires a user-defined conversion.
+
    
+
    
+If _Decimal32 is a class type, I think the call f(d) will be
+ambiguous because both the conversion to _Decimal64 and the
+conversion to S will be user-defined conversions with neither
+better than the other.
 
    
+
    
+
    
+Robert comments:
+
    
+
    In general, a library of arithmetic types cannot exactly emulate the
+behavior of the intrinsic numeric types. There are several ways to tell
+whether an implementation of the decimal types uses compiler
+intrinisics or a library. For example:
+
    
+
                     _Decimal32 d1;
+                 d1.operator+=(5);  // If d1 is a builtin type, this won't compile.
+
    
+
    
+In preparing the decimal TR, we have three options:
+
    
+
      
+
    1. require that the decimal types be class types
      2. 
+
    2. require that the decimal types be builtin types, like float and double
      3. 
+
    3. specify a library of class types, but allow enough implementor
+latitude that a conforming implementation could instead provide builtin
+types
      4. 
+
    
+
    
+We decided as a group to pursue option #3, but that approach implies
+that implementations may not agree on the semantics of certain use
+cases (first example, above), or on whether certain other cases are
+well-formed (second example). Another potentially important problem is
+that, under the present definition of POD, the decimal classes are not
+POD types, but builtins will be.
+
    
+
    Note that neither example above implies any problems with respect to
+C-to-C++ compatibility, since neither example can be expressed in C.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
+
 
 
    
 
    
-Stage 3: The result of stage 2 processing can be one of
+Decimal numeric types may either be builtin types or library types. We
+only intend to specify the common subset of behaviors of the two
+implementation approaches. The front matter of the Decimal TR says this
+explicitly.
 
    
-
      
-
    • A sequence of chars has been accumulated in stage 2 that is converted (according to the rules of scanf) to a value of the type of val.  This value is stored in val and ios_base::goodbit is stored in err.
      • 
-
-
    • The sequence of chars accumulated in stage 2 would have caused scanf to report an input failure. ios_base::failbit is assigned to err.
      • 
-
    
 
    
-In the first case, Ddigit grouping is checked.  That is, the positions of discarded separators is examined for consistency with use_facet<numpunct<charT> >(loc).grouping().  If they are not consistent then ios_base::failbit is assigned to err.  Otherwise, the value that was converted in stage 2 is stored in val and ios_base::goodbit is stored in err.
+Move to NAD.
 
    
 
    
 
 
-
    Rationale:
    
-post-Toronto: Changed from New to NAD at the request of the author.  The preferred solution of
-N2327
-makes this resolution obsolete.
+
+
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    663. Complexity Requirements
    
-
    Section: 17.5.1.4 [structure.specifications] Status: NAD
- Submitter: Thomas Plum Opened: 2007-04-16  Last modified: 2009-05-01
    
-
    View other active issues in [structure.specifications].
    
-
    View all other issues in [structure.specifications].
    
+
    606. Decimal: allow narrowing conversions
    
+
    Section: TRDecimal 3.2 [trdec.types.types] Status: NAD
+ Submitter: Martin Sebor Opened: 2006-06-15  Last modified: 2009-07-15
    
+
    View all other issues in [trdec.types.types].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-17.5.1.4 [structure.specifications] para 5 says
+In c++std-lib-17205, Martin writes:
 
    
-
-
    
--5- Complexity requirements specified in the library
-clauses are upper bounds, and implementations that provide better
-complexity guarantees satisfy the requirements.
+
    ...was it a deliberate design choice to make narrowing
+assignments ill-formed while permitting narrowing compound assignments?
+For instance:
 
    
+
          decimal32 d32;
+      decimal64 d64;
 
+      d32 = 64;     // error
+      d32 += 64;    // okay
+
    
 
    
-The following
-objection has been raised:
+In c++std-lib-17229, Robert responds:
 
    
+
    It is a vestige of an old idea that I forgot to remove
+from the paper. Narrowing assignments should be permitted. The bug is
+that the converting constructors that cause narrowing should not be
+explicit. Thanks for pointing this out.
+
    
+
+
    [
+2009-07 Frankfurt
+]
    
 
-
    
-The library clauses suggest general
-guidelines regarding complexity, but we have been unable to discover
-any absolute hard-and-fast formulae for these requirements. Unless
-or until the Library group standardizes specific hard-and-fast
-formulae, we regard all the complexity requirements as subject to a
-"fudge factor" without any intrinsic upper bound.
-
    
 
+
    
 
    
-[Plum ref
-_23213Y31 etc]
+The current state of the Decimal TR is the result of a deliberate design
+decision that has been examined many times.
+
    
+
    
+Move to NAD.
 
    
+
    
 
 
 
    Proposed resolution:
    
 
    
+1.  In "3.2.2 Class decimal32" synopsis, remove the explicit specifier from the narrowing conversions:
+
    
+
                    // 3.2.2.2 conversion from floating-point type:
+                explicit decimal32(decimal64 d64);
+                explicit decimal32(decimal128 d128);
+
    
+
    
+2.  Do the same thing in "3.2.2.2. Conversion from floating-point type."
+
    
+
    
+3.  In "3.2.3 Class decimal64" synopsis, remove the explicit specifier from the narrowing conversion:
+
    
+
                    // 3.2.3.2 conversion from floating-point type:
+                explicit decimal64(decimal128 d128);
+
    
+
    
+4.  Do the same thing in "3.2.3.2. Conversion from floating-point type."
 
    
 
+
    [
+Redmond: We prefer explicit conversions for narrowing and implicit for widening.
+]
    
 
-
    Rationale:
    
-Kona (2007): No specific instances of underspecification have been
-identified, and big-O notation always involves constant factors.
 
 
 
 
 
 
    
-
    670. money_base::pattern and space
    
-
    Section: 22.4.6.3 [locale.moneypunct] Status: Dup
- Submitter: Thomas Plum Opened: 2007-04-16  Last modified: 2008-09-22
    
-
    View all issues with Dup status.
    
-
    Duplicate of: 836
    
+
    614. std::string allocator requirements still inconsistent
    
+
    Section: 21.4 [basic.string] Status: NAD
+ Submitter: Bo Persson Opened: 2006-12-05  Last modified: 2009-07-15
    
+
    View all other issues in [basic.string].
    
+
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-22.4.6.3 [locale.moneypunct], para 2 says:
+This is based on N2134, where 21.3.1/2 states:
+"... The Allocator object used shall be a copy of the Allocator object 
+passed to the basic_string object's constructor or, if the constructor does 
+not take an Allocator argument, a copy of a default-constructed Allocator 
+object."
 
    
-
-
    
-The value space indicates that at least one space is required at 
-that position.
-
    
-
 
    
-The following objection has been raised:
+Section 21.3.2/1 lists two constructors:
 
    
+
    basic_string(const basic_string<charT,traits,Allocator>& str );
 
-
    
-Whitespace is optional when matching space. (See 22.4.6.1.2 [locale.money.get.virtuals], para 2.)
-
    
-
+basic_string(const basic_string<charT,traits,Allocator>& str ,
+             size_type pos , size_type n = npos,
+             const Allocator& a = Allocator());
+
    
 
    
-[Plum ref _22263Y22]
+and then says "In the first form, the Allocator value used is copied from 
+str.get_allocator().", which isn't an option according to 21.3.1.
 
    
+
    [
+Batavia:  We need blanket statement to the effect of:
+]
    
+
 
+
      
+
    1. If an allocator is passed in, use it, or,
      2. 
+
    2. If a string is passed in, use its allocator.
      3. 
+
    
 
    [
-Kona (2007): Bill to provide proposed wording. We agree that C++03 is
-ambiguous, and that we want C++0X to say "space" means 0 or more
-whitespace characters on input.
+Review constructors and functions that return a string; make sure we follow these
+rules (substr, operator+, etc.).  Howard to supply wording.
+]
    
+
+
+
    [
+Bo adds:  The new container constructor which takes only a size_type is not
+consistent with 23.2 [container.requirements], p9 which says in part:
+
+
    
+All other constructors for these container types take an
+Allocator& argument (20.1.2), an allocator whose value type
+is the same as the container's value type. A copy of this argument is
+used for any memory allocation performed, by these constructors and by
+all member functions, during the lifetime of each container object.
+
    
+]
    
+
+
+
    [
+post Bellevue: We re-confirm that the issue is real. Pablo will provide wording.
+]
    
+
+
+
    [
+2009-07 Frankfurt
 ]
    
 
 
+
    
+Move to NAD.
+
    
+
 
 
 
    Proposed resolution:
    
+
    
+
    
 
 
 
 
 
 
    
-
    676. Moving the unordered containers
    
-
    Section: 23.5 [unord] Status: NAD Editorial
- Submitter: Howard Hinnant Opened: 2007-05-05  Last modified: 2008-09-26
    
-
    View all other issues in [unord].
    
+
    615. Inconsistencies in Section 21.4
    
+
    Section: 21.6 [c.strings] Status: NAD Editorial
+ Submitter: Bo Persson Opened: 2006-12-11  Last modified: 2007-04-24
    
+
    View all other issues in [c.strings].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-Move semantics are missing from the unordered containers.  The proposed
-resolution below adds move-support consistent with
-N1858
-and the current working draft.
+In the current draft N2134, 21.4/1 says
 
    
-
 
    
-The current proposed resolution simply lists the requirements for each function.
-These might better be hoisted into the requirements table for unordered associative containers.
-Futhermore a mild reorganization of the container requirements could well be in order.
-This defect report is purposefully ignoring these larger issues and just focusing
-on getting the unordered containers "moved".
+"Tables 59,228) 60, 61, 62,and 63 229) 230) describe headers <cctype>, 
+<cwctype>, <cstring>, <cwchar>, and <cstdlib> (character conversions), 
+respectively."
+
    
+
    
+Here footnote 229 applies to table 62, not table 63.
+
    
+
    
+Also, footnote 230 lists the new functions in table 63, "atoll, strtoll, 
+strtoull, strtof, and strtold added by TR1". However, strtof is not present 
+in table 63.
 
    
-
 
 
 
    Proposed resolution:
    
-
 
    
-Add to 23.5 [unord]:
 
    
 
-
    template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>& y); 
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>&& y);
+
    Rationale:
    
+
    
+Recommend NAD, editorial.  Send to Pete.
+
    
+
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>& y);
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>&& y);
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
+
    
+
    626. new Remark clauses not documented
    
+
    Section: 17.5.1.4 [structure.specifications] Status: NAD Editorial
+ Submitter: Martin Sebor Opened: 2007-01-20  Last modified: 2008-02-25
    
+
    View all other issues in [structure.specifications].
    
+
    View all issues with NAD Editorial status.
    
+
    Discussion:
    
+        
    
 
-...
+The Remark clauses newly  introduced into the Working Paper 
+(N2134)
+are  not mentioned  in  17.5.1.4 [structure.specifications] where  we list  the
+meaning  of Effects, Requires,  and other  clauses (with
+the exception  of Notes which are documented  as informative in
+17.5.1.2 [structure.summary], p2, and which they replace in many cases).
 
-template <class Value, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Value, Hash, Pred, Alloc>& x, 
-            unordered_set<Value, Hash, Pred, Alloc>& y); 
+        
    
+        
    
 
-template <class Value, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Value, Hash, Pred, Alloc>& x, 
-            unordered_set<Value, Hash, Pred, Alloc>&& y);
+Propose add a bullet for Remarks along with a brief description.
 
-template <class Value, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Value, Hash, Pred, Alloc>&& x, 
-            unordered_set<Value, Hash, Pred, Alloc>& y);
+        
    
+
    [
+Batavia:  Alan and Pete to work.
+]
    
 
-template <class Value, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Value, Hash, Pred, Alloc>& x, 
-            unordered_multiset<Value, Hash, Pred, Alloc>& y);
 
-template <class Value, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Value, Hash, Pred, Alloc>& x, 
-            unordered_multiset<Value, Hash, Pred, Alloc>&& y);
+
    [
+Bellevue: Already resolved in current working paper.
+]
    
 
-template <class Value, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Value, Hash, Pred, Alloc>&& x, 
-            unordered_multiset<Value, Hash, Pred, Alloc>& y);
-
    
 
-
    unordered_map
    
 
+
    Proposed resolution:
    
 
    
-Change 23.5.1 [unord.map]:
 
    
 
-
    class unordered_map
-{
-    ...
-    unordered_map(const unordered_map&);
-    unordered_map(unordered_map&&);
-    ~unordered_map();
-    unordered_map& operator=(const unordered_map&);
-    unordered_map& operator=(unordered_map&&);
-    ...
-    // modifiers 
-    std::pair<iterator, bool> insert(const value_type& obj); 
-    template <class P> pair<iterator, bool> insert(P&& obj);
-    iterator       insert(iterator hint, const value_type& obj);
-    template <class P> iterator       insert(iterator hint, P&& obj);
-    const_iterator insert(const_iterator hint, const value_type& obj);
-    template <class P> const_iterator insert(const_iterator hint, P&& obj);
-    ...
-    void swap(unordered_map&&);
-    ...
-    mapped_type& operator[](const key_type& k);
-    mapped_type& operator[](key_type&& k);
-    ...
-};
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>& y);
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>&& y);
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>& y);
-
    
 
+
    
+
    627. Low memory and exceptions
    
+
    Section: 18.6.1.1 [new.delete.single] Status: NAD
+ Submitter: P.J. Plauger Opened: 2007-01-23  Last modified: 2008-02-25
    
+
    View all other issues in [new.delete.single].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
    
-Add to 23.5.1.1 [unord.map.cnstr]:
+I recognize the need for nothrow guarantees in the exception reporting
+mechanism, but I strongly believe that implementors also need an escape hatch
+when memory gets really low. (Like, there's not enough heap to construct and
+copy exception objects, or not enough stack to process the throw.) I'd like to
+think we can put this escape hatch in 18.6.1.1 [new.delete.single],
+operator new, but I'm not sure how to do it. We need more than a
+footnote, but the wording has to be a bit vague. The idea is that if
+new can't allocate something sufficiently small, it has the right to
+abort/call terminate/call unexpected.
 
    
 
-
    
-
    template <class InputIterator>
-  unordered_map(InputIterator f, InputIterator l, 
-                size_type n = implementation-defined, 
-                const hasher& hf = hasher(), 
-                const key_equal& eql = key_equal(), 
-                const allocator_type& a = allocator_type());
-
    
+
    [
+Bellevue: NAD.  1.4p2 specifies a program must behave correctly "within
+its resource limits", so no further escape hatch is necessary.
+]
    
 
-
    
-
-Requires: If the iterator's dereference operator returns an
-lvalue or a const rvalue pair<key_type, mapped_type>,
-then both key_type and mapped_type shall be
-CopyConstructible.
-
-
    
-
    
 
+
+
    Proposed resolution:
    
 
    
-Add to 23.5.1.2 [unord.map.elem]:
 
    
 
-
    
 
-
    mapped_type& operator[](const key_type& k);
    
 
-
    
-
    ...
    
-
    
-Requires: key_type shall be CopyConstructible
-and mapped_type shall be DefaultConstructible.
-
    
-
    
 
-
    mapped_type& operator[](key_type&& k);
    
 
+
    
+
    632. Time complexity of size() for std::set
    
+
    Section: 23.2 [container.requirements] Status: NAD
+ Submitter: Lionel B Opened: 2007-02-01  Last modified: 2009-07-15
    
+
    View other active issues in [container.requirements].
    
+
    View all other issues in [container.requirements].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    
+A recent news group discussion:
+
    
 
    
-
    
-Effects: If the unordered_map does not already contain an
-element whose key is equivalent to k , inserts the value
-std::pair<const key_type, mapped_type>(std::move(k), mapped_type()).
-
    
-
-
    
-Requires: mapped_type shall be DefaultConstructible.
-
    
-
-
    
-Returns: A reference to x.second, where x is the
-(unique) element whose key is equivalent to k.
-
    
-
-
    
+
    
+Anyone know if the Standard has anything to say about the time complexity
+of size() for std::set?   I need to access a set's size (/not/ to know if it is empty!) heavily
+during an algorithm and was thus wondering whether I'd be better off
+tracking the size "manually" or whether that'd be pointless.
+
    
+
    
+That would be pointless. size() is O(1).
+
    
+
    
+Nit: the standard says "should" have constant time. Implementations may take
+license to do worse. I know that some do this for std::list<> as a part of
+some trade-off with other operation.
+
    
 
+
    
+I was aware of that, hence my reluctance to use size() for std::set.
+
    
+
    
+However, this reason would not apply to std::set<> as far as I can see.
+
    
+
    
+Ok, I guess the only option is to try it and see...
+
    
 
    
 
 
    
-Add new section [unord.map.modifiers]:
+If I have any recommendation to the C++ Standards Committee it is that
+implementations must (not "should"!) document clearly[1], where known, the
+time complexity of *all* container access operations.
+
    
+
    
+[1] In my case (gcc 4.1.1) I can't swear that the time complexity of size()
+for std::set is not documented... but if it is it's certainly well hidden
+away.
 
    
 
-
    
-
    pair<iterator, bool> insert(const value_type& x);
-template <class P> pair<iterator, bool> insert(P&& x);
-iterator       insert(iterator hint, const value_type& x);
-template <class P> iterator       insert(iterator hint, P&& x);
-const_iterator insert(const_iterator hint, const value_type& x);
-template <class P> const_iterator insert(const_iterator hint, P&& x);
-template <class InputIterator>
-  void insert(InputIterator first, InputIterator last);
-
    
+
    [
+Kona (2007): This issue affects all the containers. We'd love to see a
+paper dealing with the broad issue. We think that the complexity of the
+size() member of every container -- except possibly list -- should be
+O(1). Alan has volunteered to provide wording.
+]
    
 
-
    
-
    
-Requires: Those signatures taking a const value_type& parameter
-requires both the key_type and the mapped_type to be
-CopyConstructible.
-
    
 
-
    
-P shall be convertible to value_type.
- If P is instantiated as a reference
-type, then the argument x is copied from. Otherwise x
-is considered to be an rvalue as it is converted to value_type
-and inserted into the unordered_map. Specifically, in such
-cases CopyConstructible is not required of key_type or
-mapped_type unless the conversion from P specifically
-requires it (e.g. if P is a tuple<const key_type,
-mapped_type>, then key_type must be
-CopyConstructible).
-
    
+
    [
+Bellevue:
+]
    
 
-
    
-The signature taking InputIterator
-parameters requires CopyConstructible of both
-key_type and mapped_type if the dereferenced
-InputIterator returns an lvalue or const rvalue
-value_type.
-
    
 
+
    
+Mandating O(1) size will not fly, too many implementations would be
+invalidated. Alan to provide wording that toughens wording, but that
+does not absolutely mandate O(1).
 
    
 
+
    [
+Batavia (2009-05):
+]
    
+
+
    
+We observed that the wording "should" (in note a) has no effect.
+Howard prefers that O(1) size be mandated.
+It is not clear that this issue can be resolved to everyone's satisfaction,
+but Alan will provide wording nonetheless.
 
    
 
-
    
-Add to 23.5.1.3 [unord.map.swap]:
-
    
+
    [
+2009-07 Frankfurt
+]
    
+
 
 
    
-
    template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>&& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_map<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_map<Key, T, Hash, Pred, Alloc>& y);
-
    
+Fixed by paper N2923.
 
    
 
-
    unordered_multimap
    
 
+
+
    Proposed resolution:
    
 
    
-Change 23.5.2 [unord.multimap]:
 
    
 
-
    class unordered_multimap
-{
-    ...
-    unordered_multimap(const unordered_multimap&);
-    unordered_multimap(unordered_multimap&&);
-    ~unordered_multimap();
-    unordered_multimap& operator=(const unordered_multimap&);
-    unordered_multimap& operator=(unordered_multimap&&);
-    ...
-    // modifiers 
-    iterator insert(const value_type& obj); 
-    template <class P> iterator insert(P&& obj);
-    iterator       insert(iterator hint, const value_type& obj);
-    template <class P> iterator       insert(iterator hint, P&& obj);
-    const_iterator insert(const_iterator hint, const value_type& obj);
-    template <class P> const_iterator insert(const_iterator hint, P&& obj);
-    ...
-    void swap(unordered_multimap&&);
-    ...
-};
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>&& y);
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
-
    
 
+
    
+
    633. Return clause mentions undefined "type()"
    
+
    Section: 20.7.16.2.5 [func.wrap.func.targ] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2007-02-03  Last modified: 2007-07-02
    
+
    View all issues with NAD Editorial status.
    
+
    Discussion:
    
 
    
-Add to 23.5.2.1 [unord.multimap.cnstr]:
+20.7.16.2.5 [func.wrap.func.targ], p4 says:
 
    
-
-
    
-
    template <class InputIterator>
-  unordered_multimap(InputIterator f, InputIterator l, 
-                size_type n = implementation-defined, 
-                const hasher& hf = hasher(), 
-                const key_equal& eql = key_equal(), 
-                const allocator_type& a = allocator_type());
-
    
-
 
    
-
-Requires: If the iterator's dereference operator returns an
-lvalue or a const rvalue pair<key_type, mapped_type>,
-then both key_type and mapped_type shall be
-CopyConstructible.
-
+Returns: If type() == typeid(T), a pointer to the stored
+function target; otherwise a null pointer.
 
    
-
    
-
-
    
-Add new section [unord.multimap.modifiers]:
-
    
 
-
    
-
    iterator insert(const value_type& x);
-template <class P> iterator       insert(P&& x);
-iterator       insert(iterator hint, const value_type& x);
-template <class P> iterator       insert(iterator hint, P&& x);
-const_iterator insert(const_iterator hint, const value_type& x);
-template <class P> const_iterator insert(const_iterator hint, P&& x);
-template <class InputIterator>
-  void insert(InputIterator first, InputIterator last);
-
    
-
-
    
-
    
-Requires: Those signatures taking a const value_type& parameter
-requires both the key_type and the mapped_type to be
-CopyConstructible.
-
    
-
-
    
-P shall be convertible to value_type.
- If P is instantiated as a reference
-type, then the argument x is copied from. Otherwise x
-is considered to be an rvalue as it is converted to value_type
-and inserted into the unordered_multimap. Specifically, in such
-cases CopyConstructible is not required of key_type or
-mapped_type unless the conversion from P specifically
-requires it (e.g. if P is a tuple<const key_type,
-mapped_type>, then key_type must be
-CopyConstructible).
-
    
+
      
+
    1. 
+There exists neither a type, a typedef type, nor member
+function type() in class template function nor in the global or
+std namespace.
+
      2. 
+
    2. 
+Assuming that type should have been target_type(),
+this description would lead to false results, if T = cv
+void due to returns clause 20.7.16.2.5 [func.wrap.func.targ], p1.
+
      3. 
+
    
 
-
    
-The signature taking InputIterator
-parameters requires CopyConstructible of both
-key_type and mapped_type if the dereferenced
-InputIterator returns an lvalue or const rvalue
-value_type.
-
    
-
    
 
-
    
 
+
    Proposed resolution:
    
 
    
-Add to 23.5.2.2 [unord.multimap.swap]:
+Change 20.7.16.2.5 [func.wrap.func.targ], p4:
 
    
 
-
    
-
    template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>&& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
-
    
-
    
+
    
+Returns: If type() target_type() == typeid(T) && typeid(T) !=
+typeid(void), a pointer to the stored function target;
+otherwise a null pointer.
+
    
+
+
    [
+Pete: Agreed. It's editorial, so I'll fix it.
+]
    
 
-
    unordered_set
    
 
-
    
-Change 23.5.3 [unord.set]:
-
    
 
-
    class unordered_set
-{
-    ...
-    unordered_set(const unordered_set&);
-    unordered_set(unordered_set&&);
-    ~unordered_set();
-    unordered_set& operator=(const unordered_set&);
-    unordered_set& operator=(unordered_set&&);
-    ...
-    // modifiers 
-    std::pair<iterator, bool> insert(const value_type& obj); 
-    pair<iterator, bool> insert(value_type&& obj);
-    iterator       insert(iterator hint, const value_type& obj);
-    iterator       insert(iterator hint, value_type&& obj);
-    const_iterator insert(const_iterator hint, const value_type& obj);
-    const_iterator insert(const_iterator hint, value_type&& obj);
-    ...
-    void swap(unordered_set&&);
-    ...
-};
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_set<Key, T, Hash, Pred, Alloc>& y);
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_set<Key, T, Hash, Pred, Alloc>&& y);
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_set<Key, T, Hash, Pred, Alloc>& y);
-
    
 
+
    
+
    636. 26.5.2.3 valarray::operator[]
    
+
    Section: 26.6.2.3 [valarray.access] Status: NAD Editorial
+ Submitter: Bo Persson Opened: 2007-02-11  Last modified: 2007-07-02
    
+
    View all other issues in [valarray.access].
    
+
    View all issues with NAD Editorial status.
    
+
    Discussion:
    
+
    
+The signature of the const operator[] has been changed to return a const 
+reference.
+
    
 
    
-Add to 23.5.3.1 [unord.set.cnstr]:
+The description in paragraph 1 still says that the operator returns by 
+value.
 
    
+
    [
+Pete recommends editorial fix.
+]
    
 
-
    
-
    template <class InputIterator>
-  unordered_set(InputIterator f, InputIterator l, 
-                size_type n = implementation-defined, 
-                const hasher& hf = hasher(), 
-                const key_equal& eql = key_equal(), 
-                const allocator_type& a = allocator_type());
-
    
 
-
    
-
-Requires: If the iterator's dereference operator returns an
-lvalue or a const rvalue value_type, then the
-value_type shall be CopyConstructible.
-
-
    
-
    
 
+
    Proposed resolution:
    
 
    
-Add new section [unord.set.modifiers]:
 
    
 
-
    
-
    pair<iterator, bool> insert(const value_type& x);
-pair<iterator, bool> insert(value_type&& x);
-iterator       insert(iterator hint, const value_type& x);
-iterator       insert(iterator hint, value_type&& x);
-const_iterator insert(const_iterator hint, const value_type& x);
-const_iterator insert(const_iterator hint, value_type&& x);
-template <class InputIterator>
-  void insert(InputIterator first, InputIterator last);
-
    
-
-
    
-
-
    
-Requires: Those signatures taking a const
-value_type& parameter requires the value_type to
-be CopyConstructible.
-
    
 
-
    
-The signature taking InputIterator parameters requires
-CopyConstructible of value_type if the dereferenced
-InputIterator returns an lvalue or const rvalue
-value_type.
-
    
 
-
    
 
-
    
 
+
    
+
    637. [c.math]/10 inconsistent return values
    
+
    Section: 26.8 [c.math] Status: NAD Editorial
+ Submitter: Bo Persson Opened: 2007-02-13  Last modified: 2007-07-26
    
+
    View all other issues in [c.math].
    
+
    View all issues with NAD Editorial status.
    
+
    Discussion:
    
 
    
-Add to 23.5.3.2 [unord.set.swap]:
+26.8 [c.math], paragraph 10 has long lists of added signatures for float and long double 
+functions. All the signatures have float/long double return values, which is 
+inconsistent with some of the double functions they are supposed to 
+overload.
 
    
 
-
    
-
    template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_set<Key, T, Hash, Pred, Alloc>& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_set<Key, T, Hash, Pred, Alloc>&& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_set<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_set<Key, T, Hash, Pred, Alloc>& y);
-
    
-
    
-
-
    unordered_multiset
    
 
+
    Proposed resolution:
    
 
    
-Change 23.5.4 [unord.multiset]:
+Change 26.8 [c.math], paragraph 10,
 
    
 
-
    class unordered_multiset
-{
-    ...
-    unordered_multiset(const unordered_multiset&);
-    unordered_multiset(unordered_multiset&&);
-    ~unordered_multiset();
-    unordered_multiset& operator=(const unordered_multiset&);
-    unordered_multiset& operator=(unordered_multiset&&);
-    ...
-    // modifiers 
-    iterator insert(const value_type& obj); 
-    iterator insert(value_type&& obj);
-    iterator       insert(iterator hint, const value_type& obj);
-    iterator       insert(iterator hint, value_type&& obj);
-    const_iterator insert(const_iterator hint, const value_type& obj);
-    const_iterator insert(const_iterator hint, value_type&& obj);
-    ...
-    void swap(unordered_multiset&&);
-    ...
-};
+
    float int ilogb(float);
+float long lrint(float);
+float long lround(float);
+float long long llrint(float);
+float long long llround(float);
+
+long double int ilogb(long double);
+long double long lrint(long double);
+long double long lround(long double);
+long double long long llrint(long double);
+long double long long llround(long double);
+
    
+
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multiset<Key, T, Hash, Pred, Alloc>& y);
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multiset<Key, T, Hash, Pred, Alloc>&& y);
 
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_multiset<Key, T, Hash, Pred, Alloc>& y);
-
    
 
+
    
+
    639. Still problems with exceptions during streambuf IO
    
+
    Section: 27.7.1.2.3 [istream::extractors], 27.7.2.6.3 [ostream.inserters] Status: NAD
+ Submitter: Daniel Krügler Opened: 2007-02-17  Last modified: 2007-10-10
    
+
    View all other issues in [istream::extractors].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
    
-Add to 23.5.4.1 [unord.multiset.cnstr]:
+There already exist two active DR's for the wording of 27.7.1.2.3 [istream::extractors]/13
+from 14882:2003(E), namely 64 and 413.
 
    
 
-
    
-
    template <class InputIterator>
-  unordered_multiset(InputIterator f, InputIterator l, 
-                size_type n = implementation-defined, 
-                const hasher& hf = hasher(), 
-                const key_equal& eql = key_equal(), 
-                const allocator_type& a = allocator_type());
-
    
+
    
+Even with these proposed corrections, already maintained in N2134,
+I have the feeling, that the current wording does still not properly
+handle the "exceptional" situation. The combination of para 14
+
    
 
 
    
-
-Requires: If the iterator's dereference operator returns an
-lvalue or a const rvalue value_type, then the
-value_type shall be CopyConstructible.
-
+"[..] Characters are extracted and inserted until
+any of the following occurs:
+
    
+
    
+[..]
+
    
+
    
+- an exception occurs (in which case the exception is caught)."
 
    
-
    
 
 
    
-Add new section [unord.multiset.modifiers]:
+and 15
 
    
 
-
    
-
    iterator insert(const value_type& x);
-iterator insert(value_type&& x);
-iterator       insert(iterator hint, const value_type& x);
-iterator       insert(iterator hint, value_type&& x);
-const_iterator insert(const_iterator hint, const value_type& x);
-const_iterator insert(const_iterator hint, value_type&& x);
-template <class InputIterator>
-  void insert(InputIterator first, InputIterator last);
-
    
-
-
    
+
    
+"If the function inserts no characters, it calls setstate(failbit),
+which
+may throw ios_base::failure (27.4.4.3). If it inserted no characters
+because it caught an exception thrown while extracting characters
+from *this and failbit is on in exceptions() (27.4.4.3), then the
+caught
+exception is rethrown."
+
    
 
-
    
-Requires: Those signatures taking a const
-value_type& parameter requires the value_type to
-be CopyConstructible.
-
    
+
    
+both in N2134 seems to imply that any exception, which occurs
+*after* at least one character has been inserted is caught and lost
+for
+ever. It seems that even if failbit is on in exceptions() rethrow is
+not
+allowed due to the wording "If it inserted no characters because it
+caught an exception thrown while extracting".
+
    
 
-
    
-The signature taking InputIterator parameters requires
-CopyConstructible of value_type if the dereferenced
-InputIterator returns an lvalue or const rvalue
-value_type.
-
    
+
    
+Is this behaviour by design?
+
    
 
-
    
+
    
+I would like to add that its output counterpart in 27.7.2.6.3 [ostream.inserters]/7-9
+(also
+N2134) does not demonstrate such an exception-loss-behaviour.
+On the other side, I wonder concerning several subtle differences
+compared to input::
+
    
+
    
+1) Paragraph 8 says at its end:
+
    
 
-
    
+
    
+"- an exception occurs while getting a character from sb."
+
    
 
 
    
-Add to 23.5.4.2 [unord.multiset.swap]:
+Note that there is nothing mentioned which would imply that such
+an exception will be caught compared to 27.7.1.2.3 [istream::extractors]/14.
 
    
 
-
    
-
    template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multiset<Key, T, Hash, Pred, Alloc>& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>& x, 
-            unordered_multiset<Key, T, Hash, Pred, Alloc>&& y);
-template <class Key, class T, class Hash, class Pred, class Alloc> 
-  void swap(unordered_multiset<Key, T, Hash, Pred, Alloc>&& x, 
-            unordered_multiset<Key, T, Hash, Pred, Alloc>& y);
-
    
-
    
-
+
    
+2) Paragraph 9 says:
+
    
 
+
    
+"If the function inserts no characters, it calls setstate(failbit)
+(which
+may throw ios_base::failure (27.4.4.3)). If an exception was thrown
+while extracting a character, the function sets failbit in error
+state,
+and if failbit is on in exceptions() the caught exception is
+rethrown."
+
    
 
-
    [
-Voted to WP in Bellevue.
-]
    
+
    
+The sentence starting with "If an exception was thrown" seems to
+imply that such an exception *should* be caught before.
+
    
 
 
-
    [
-post Bellevue, Pete notes:
-]
    
+
    Proposed resolution:
    
+
    
+(a) In 27.7.1.2.3 [istream::extractors]/15 (N2134) change the sentence
+
    
 
+
    
+If the function inserts no characters, it calls
+setstate(failbit), which may throw ios_base::failure
+(27.4.4.3). If it inserted no characters because it caught an
+exception thrown while extracting characters from *this
+an exception was thrown while extracting a character from
+*this, the function sets failbit in error state,
+and failbit is on in exceptions() (27.4.4.3), then the
+caught exception is rethrown.
+
    
 
-
    
 
    
-Please remind people who are reviewing issues to check that the text
-modifications match the current draft. Issue 676, for example, adds two
-overloads for unordered_map::insert taking a hint. One takes a
-const_iterator and returns a const_iterator, and the other takes an
-iterator and returns an iterator. This was correct at the time the issue
-was written, but was changed in Toronto so there is only one hint
-overload, taking a const_iterator and returning an iterator.
+(b) In 27.7.2.6.3 [ostream.inserters]/8 (N2134) change the sentence:
 
    
+
+
    
 
    
-This issue is not ready. In addition to the relatively minor signature
-problem I mentioned earlier, it puts requirements in the wrong places.
-Instead of duplicating requirements throughout the template
-specifications, it should put them in the front matter that talks about
-requirements for unordered containers in general. This presentation
-problem is editorial, but I'm not willing to do the extensive rewrite
-that it requires. Please put it back into Open status.
+Gets characters from sb and inserts them in *this.
+Characters are read from sb and inserted until any of the
+following occurs:
 
    
+
      
+
    • end-of-file occurs on the input sequence;
      • 
+
    • inserting in the output sequence fails (in which case the character to be inserted is not extracted);
      • 
+
    • an exception occurs while getting a character from sb (in which
+case the exception is caught).
      • 
+
    
 
    
 
-
    Rationale:
    
-
    [
-San Francisco:
-]
    
-
 
-
    
-Solved by
-N2776.
-
    
 
+
    Rationale:
    
+This extractor is described as a formatted input function so the
+exception behavior is already specified. There is additional behavior
+described in this section that applies to the case in which failbit is
+set. This doesn't contradict the usual exception behavior for formatted
+input functions because that applies to the case in which badbit is set.
 
 
 
 
 
 
    
-
    683. regex_token_iterator summary error
    
-
    Section: 28.13.2 [re.tokiter] Status: NAD Editorial
- Submitter: Eric Niebler Opened: 2007-06-02  Last modified: 2009-03-09
    
-
    View all other issues in [re.tokiter].
    
+
    641. Editorial fix for 27.6.4 (N2134)
    
+
    Section: 27.7.4 [ext.manip] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2007-02-18  Last modified: 2007-07-02
    
+
    View all other issues in [ext.manip].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-28.13.2 [re.tokiter], p3 says:
-
    
-
    
-
    
-After it is constructed, the iterator finds and stores a value
-match_results<BidirectionalIterator> position and sets the
-internal count N to zero.
+The function f in para 4 (27.7.4 [ext.manip]) references an unknown strm
+in the following line:
 
    
-
    
 
-
    
-Should read:
-
    
+
    mg.get(Iter(str.rdbuf()), Iter(), intl, strm, err, mon);
+
    
 
-
    
+
+
    Proposed resolution:
    
 
    
-After it is constructed, the iterator finds and stores a value
-match_resultsregex_iterator<BidirectionalIterator, charT, traits>
-position and sets the internal count N to zero.
+Change 27.7.4 [ext.manip], p4:
 
    
-
    
+
+
    mg.get(Iter(str.rdbuf()), Iter(), intl, strm, err, mon);
+
    
 
 
    [
-John adds:
+Oxford:  Editorial.
 ]
    
 
 
-
    
-Yep, looks like a typo/administrative fix to me.
-
    
-
-
-
-
    Proposed resolution:
    
-
    
-
    
 
 
 
 
 
 
    
-
    684. Unclear which members of match_results should be used in comparison
    
-
    Section: 28.11 [re.results] Status: NAD Editorial
- Submitter: Nozomu Katoo Opened: 2007-05-27  Last modified: 2008-03-12
    
-
    View all other issues in [re.results].
    
+
    642. Invalidated fstream footnotes in N2134
    
+
    Section: 27.9.1.9 [ifstream.members], 27.9.1.13 [ofstream.members] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2007-02-20  Last modified: 2007-07-02
    
+
    View all other issues in [ifstream.members].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-In 28.5 [re.syn] of N2284, two template functions 
-are declared here: 
+The standard wording of N2134 has extended the 14882:2003(E)
+wording for the ifstream/ofstream/fstream open function to fix
+a long standing problem, see 409.
 
    
-
    // 28.10, class template match_results: 
-  <snip>
-// match_results comparisons 
-  template <class BidirectionalIterator, class Allocator> 
-    bool operator== (const match_results<BidirectionalIterator, Allocator>& m1, 
-                     const match_results<BidirectionalIterator, Allocator>& m2); 
-  template <class BidirectionalIterator, class Allocator> 
-    bool operator!= (const match_results<BidirectionalIterator, Allocator>& m1, 
-                     const match_results<BidirectionalIterator, Allocator>& m2); 
-
-// 28.10.6, match_results swap:
-
    
 
 
    
-But the details of these two bool operator functions (i.e., which members of
-match_results should be used in comparison) are not described in any
-following sections.
+Now it's properly written as
 
    
 
-
    [
-John adds:
-]
    
-
-
 
    
-That looks like a bug: operator== should return true only if
-the two objects refer to the same match - ie if one object was constructed as a
-copy of the other.
+"If that function does not return a null pointer calls clear(),
+otherwise
+calls setstate(failbit)[..]"
 
    
 
-
    [
-Kona (2007): Bill and Pete to add minor wording to that proposed in
-N2409.
-]
    
-
-
-
-
    Proposed resolution:
    
 
    
-Add a new section after 28.11.6 [re.results.swap], which reads:
+instead of the previous
 
    
+
+
    
+"If that function returns a null pointer, calls setstate(failbit)[..]
+
    
+
 
    
-28.10.7 match_results non-member functions.
+While the old footnotes saying
 
    
 
-
    
-
    template<class BidirectionalIterator, class Allocator> 
-  bool operator==(const match_results<BidirectionalIterator, Allocator>& m1, 
-                  const match_results<BidirectionalIterator, Allocator>& m2);
-
    
-
    
+
    
+"A successful open does not change the error state."
+
    
+
 
    
-Returns: true only if the two objects refer to the same match.
+where correct and important, they are invalid now for ifstream and
+ofstream (because clear *does* indeed modify the error state) and
+should be removed (Interestingly fstream itself never had these,
+although
+they where needed for that time).
 
    
-
    
-
    
 
-
    
-
    template<class BidirectionalIterator, class Allocator> 
-  bool operator!=(const match_results<BidirectionalIterator, Allocator>& m1, 
-                  const match_results<BidirectionalIterator, Allocator>& m2);
-
    
-
    
+
+
    Proposed resolution:
    
 
    
-Returns: !(m1 == m2).
+In 27.9.1.9 [ifstream.members], remove footnote:
 
    
-
    
-
    
 
-
    
-
    template<class BidirectionalIterator, class Allocator> 
-  void swap(match_results<BidirectionalIterator, Allocator>& m1, 
-            match_results<BidirectionalIterator, Allocator>& m2);
-
    
-
    
+
    
+334) A successful open does not change the error state.
+
    
+
 
    
-Returns: m1.swap(m2).
+In 27.9.1.13 [ofstream.members], remove footnote:
 
    
-
    
-
    
 
+
    
+335) A successful open does not change the error state.
+
    
 
-
    [
-Bellevue:  Proposed wording now in WP.
-]
    
 
 
 
 
 
 
    
-
    686. Unique_ptr and shared_ptr fail to specify non-convertibility to int for unspecified-bool-type
    
-
    Section: 20.8.12.2.4 [unique.ptr.single.observers], 20.8.13.2.5 [util.smartptr.shared.obs] Status: NAD
- Submitter: Beman Dawes Opened: 2007-06-14  Last modified: 2008-02-27
    
+
    644. Possible typos in 'function' description
    
+
    Section: 20.7.16.2 [func.wrap.func] Status: NAD
+ Submitter: Bo Persson Opened: 2007-02-25  Last modified: 2009-07-13
    
+
    View all other issues in [func.wrap.func].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-The standard library uses the operator unspecified-bool-type() const idiom in
-five places. In three of those places (20.7.16.2.3 [func.wrap.func.cap], function capacity 
-for example) the returned value is constrained to disallow
-unintended conversions to int. The standardese is
+20.7.16.2 [func.wrap.func]
 
    
-
    
-The return type shall not be convertible to int.
-
    
 
    
-This constraint is omitted for unique_ptr and shared_ptr. It should be added for those.
+The note in paragraph 2 refers to 'undefined void operators', while the
+section declares a pair of operators returning bool.
 
    
 
 
    [
-Bellevue:
+Post-Sophia Antipolis:
 ]
    
 
 
 
    
-Close as NAD. Accepting paper
-N2435
-makes it irrelevant.
+Changed from Pending WP to Open.  This issue was voted to WP at the same time the operators were
+changed from private to deleted.  The two issues stepped on each other.  What do we want the return
+type of these deleted functions to be?
 
    
 
+
    [
+2009-05-02 Daniel adds:
+]
    
 
 
-
    Proposed resolution:
    
+
    
 
    
-To the Returns paragraph for operator unspecified-bool-type()
-const
-of 20.8.12.2.4 [unique.ptr.single.observers] paragraph 11 and
-20.8.13.2.5 [util.smartptr.shared.obs] paragraph 16, add the sentence:
+I suggest harmonizing this issue with similar classes. E.g. in
+20.8.10.3 [util.smartptr.weak] bool return values for
 
    
-
    
-The return type shall not be convertible to int.
-
    
+
    template <class Y> bool operator<(weak_ptr<Y> const&) const = delete;
+template <class Y> bool operator<=(weak_ptr<Y> const&) const = delete;
+template <class Y> bool operator>(weak_ptr<Y> const&) const = delete;
+template <class Y> bool operator>=(weak_ptr<Y> const&) const = delete;
+
    
 
+
    
+are used and basically all newer provided deleted copy assignment operators
+of type X use the canonical return type X& instead of void. Since the note
+mentioned in the issue description has now already been changed to
+
    
+
    
+deleted overloads close possible hole in the type system
+
    
+
    
+it seems to be of even lesser need to perform the change. Therefore
+I recommend declaring the issue as NAD.
+
    
+
    
 
 
    [
-Kona (2007): Uncertain if nullptr will address this issue.
+Batavia (2009-05):
 ]
    
 
-
-
-
-
-
    
-
    690. abs(long long) should return long long
    
-
    Section: 26.8 [c.math] Status: NAD Editorial
- Submitter: Niels Dekker Opened: 2007-06-10  Last modified: 2007-07-25
    
-
    View all other issues in [c.math].
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
-
    
-Quoting the latest draft (n2135), 26.8 [c.math]: 
-
    
-
 
    
 
    
-The added signatures are:
+We agree with Daniel's recommendation.
 
    
-
    long abs(long); // labs()
-long abs(long long); // llabs()
-
    
-
    
 
    
-Shouldn't abs(long long) have long long as return type?
+Move to NAD.
 
    
+
    
 
 
 
    Proposed resolution:
    
 
    
-Change 26.8 [c.math]: 
+Change 20.7.16.2 [func.wrap.func]
 
    
-
    long long abs(long long); // llabs()
+
+
    ...
+private:
+   // 20.7.16.2 [func.wrap.func], undefined operators:
+   template<class Function2> bool void operator==(const function<Function2>&);
+   template<class Function2> bool void operator!=(const function<Function2>&);
+};
 
    
 
+
    
+Change 20.7.16.2 [func.wrap.func]
+
    
 
-
    Rationale:
    
-Had already been fixed in the WP by the time the LWG reviewed this.
+
    template<class Function2> bool void operator==(const function<Function2>&);
+template<class Function2> bool void operator!=(const function<Function2>&);
+
    
 
 
 
 
 
 
    
-
    697. New <system_error> header leads to name clashes
    
-
    Section: 19.5 [syserr] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2007-06-24  Last modified: 2008-01-06
    
-
    View all other issues in [syserr].
    
+
    645. Missing members in match_results
    
+
    Section: 28.10 [re.results] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2007-02-26  Last modified: 2008-03-12
    
+
    View all other issues in [re.results].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-The most recent state of 
-N2241
-as well as the current draft
-N2284
-(section 19.5 [syserr], p.2) proposes a
-new
-enumeration type posix_errno immediatly in the namespace std. One of
-the enumerators has the name invalid_argument, or fully qualified:
-std::invalid_argument. This name clashes with the exception type
-std::invalid_argument, see 19.2 [std.exceptions]/p.3. This clash makes
-e.g. the following snippet invalid:
+According to the description given in 28.10 [re.results]/2 the class template
+match_results "shall satisfy the requirements of a Sequence, [..],
+except that only operations defined for const-qualified Sequences
+are supported".
+Comparing the provided operations from 28.10 [re.results]/3 with the
+sequence/container tables 80 and 81 one recognizes the following
+missing operations:
 
    
 
-
    #include <system_error>
-#include <stdexcept>
+
    
+1) The members
+
    
 
-void foo() { throw std::invalid_argument("Don't call us - we call you!"); }
+
    const_iterator rbegin() const;
+const_iterator rend() const;
 
    
 
 
    
-I propose that this enumeration type (and probably the remaining parts
-of
-<system_error> as well) should be moved into one additional inner
-namespace, e.g. sys or system to reduce foreseeable future clashes
-due
-to the great number of members that std::posix_errno already contains
-(Btw.: Why has the already proposed std::sys sub-namespace from
-N2066
-been rejected?). A further clash candidate seems to be
-std::protocol_error
-(a reasonable name for an exception related to a std network library,
-I guess).
-
    
-
-
    
-Another possible resolution would rely on the proposed strongly typed
-enums,
-as described in N2213.
-But maybe the forbidden implicit conversion to integral types would
-make
-these enumerators less attractive in this special case?
+should exists because 23.1/10 demands these for containers
+(all sequences are containers) which support bidirectional
+iterators. Aren't these supported by match_result? This is not
+explicitely expressed, but it's somewhat implied by two arguments:
 
    
-
-
-
    Proposed resolution:
    
 
    
-Fixed by issue 7 of N2422.
+(a) Several typedefs delegate to
+iterator_traits<BidirectionalIterator>.
 
    
-
-
-
-
-
-
-
    
-
    704. MoveAssignable requirement for container value type overly strict
    
-
    Section: 23.2 [container.requirements] Status: NAD Editorial
- Submitter: Howard Hinnant Opened: 2007-05-20  Last modified: 2008-09-26
    
-
    View other active issues in [container.requirements].
    
-
    View all other issues in [container.requirements].
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
 
    
-The move-related changes inadvertently overwrote the intent of 276.
-Issue 276 removed the requirement of CopyAssignable from
-most of the member functions of node-based containers.  But the move-related changes
-unnecessarily introduced the MoveAssignable requirement for those members which used to
-require CopyAssignable.
+(b) The existence of const_reference operator[](size_type n) const
+implies even random-access iteration.
+I also suggest, that match_result should explicitly mention,
+which minimum iterator category is supported and if this does
+not include random-access the existence of operator[] is
+somewhat questionable.
 
    
-
 
    
-We also discussed (c++std-lib-18722) the possibility of dropping MoveAssignable
-from some of the sequence requirements.  Additionally the in-place construction
-work may further reduce requirements.  For purposes of an easy reference, here are the
-minimum sequence requirements as I currently understand them.  Those items in requirements
-table in the working draft which do not appear below have been purposefully omitted for
-brevity as they do not have any requirements of this nature.  Some items which do not
-have any requirements of this nature are included below just to confirm that they were
-not omitted by mistake.
+2) The new "convenience" members
 
    
-
-
-
-
-
-
-
-
-
    Container Requirements
    X u(a)value_type must be CopyConstructible
    X u(rv)array and containers with a propagate_never allocator require value_type to be MoveConstructible
    a = uSequences require value_type to be CopyConstructible and CopyAssignable.
-                               Associative containers require value_type to be CopyConstructible.
    a = rvarray requires value_type to be MoveAssignable.
-                                Sequences and Associative containers with propagate_never and propagate_on_copy_construction allocators require value_type to be MoveConstructible.
    swap(a,u)array and containers with propagate_never and
-                  propagate_on_copy_construction allocators require value_type to be Swappable.
    
-
+
    const_iterator cbegin() const;
+const_iterator cend() const;
+const_iterator crbegin() const;
+const_iterator crend() const;
+
    
 
    
+should be added according to tables 80/81.
 
    
 
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
    Sequence Requirements
    X(n)value_type must be DefaultConstructible
    X(n, t)value_type must be CopyConstructible
    X(i, j)If the iterators return an lvalue the value_type must be CopyConstructible.
-                                 If the iterators return an rvalue the value_type must be MoveConstructible.
    a.insert(p, t)The value_type must be CopyConstructible.
-                                        The sequences vector and deque also require the value_type to be CopyAssignable.
    a.insert(p, rv)The value_type must be MoveConstructible.
-                                        The sequences vector and deque also require the value_type to be MoveAssignable.
    a.insert(p, n, t)The value_type must be CopyConstructible.
-                                        The sequences vector and deque also require the value_type to be CopyAssignable.
    a.insert(p, i, j)If the iterators return an lvalue the value_type must be CopyConstructible.
-                                        The sequences vector and deque also require the value_type to be CopyAssignable when the iterators return an lvalue.
-                                        If the iterators return an rvalue the value_type must be MoveConstructible.
-                                        The sequences vector and deque also require the value_type to be MoveAssignable when the iterators return an rvalue.
    a.erase(p)The sequences vector and deque require the value_type to be MoveAssignable.
    a.erase(q1, q2)The sequences vector and deque require the value_type to be MoveAssignable.
    a.clear()
    a.assign(i, j)If the iterators return an lvalue the value_type must be CopyConstructible and CopyAssignable.
-                                        If the iterators return an rvalue the value_type must be MoveConstructible and MoveAssignable.
    a.assign(n, t)The value_type must be CopyConstructible and CopyAssignable.
    a.resize(n)The value_type must be DefaultConstructible.
-                                     The sequence vector also requires the value_type to be MoveConstructible.
    a.resize(n, t)The value_type must be CopyConstructible.
    
 
+
    Proposed resolution:
    
 
    
+Add the following members to the match_results synopsis after end() in 28.10 [re.results]
+para 3:
 
    
 
-
-
-
-
-
-
-
-
-
-
-
-
-
    Optional Sequence Requirements
    a.front()
    a.back()
    a.push_front(t)The value_type must be CopyConstructible.
    a.push_front(rv)The value_type must be MoveConstructible.
    a.push_back(t)The value_type must be CopyConstructible.
    a.push_back(rv)The value_type must be MoveConstructible.
    a.pop_front()
    a.pop_back()
    a[n]
    a.at[n]
    
+
    const_iterator cbegin() const; 
+const_iterator cend() const;
+
    
 
 
    
+In section 28.10.3 [re.results.acc] change:
 
    
 
-
-
-
-
-
-
-
-
-
-
-
    Associative Container Requirements
    X(i, j)If the iterators return an lvalue the value_type must be CopyConstructible.
-                                 If the iterators return an rvalue the value_type must be MoveConstructible.
    a_uniq.insert(t)The value_type must be CopyConstructible.
    a_uniq.insert(rv)The key_type and the mapped_type (if it exists) must be MoveConstructible.
    a_eq.insert(t)The value_type must be CopyConstructible.
    a_eq.insert(rv)The key_type and the mapped_type (if it exists) must be MoveConstructible.
    a.insert(p, t)The value_type must be CopyConstructible.
    a.insert(p, rv)The key_type and the mapped_type (if it exists) must be MoveConstructible.
    a.insert(i, j)If the iterators return an lvalue the value_type must be CopyConstructible.
-                                        If the iterators return an rvalue the key_type and the mapped_type (if it exists) must be MoveConstructible..
    
-
+
    
+
    const_iterator begin() const;
+const_iterator cbegin() const;
+
    
+
    
 
    
+-7- Returns: A starting iterator that enumerates over all the sub-expressions stored in *this.
 
    
+
    
 
-
-
-
-
-
-
-
-
-
-
-
    Unordered Associative Container Requirements
    X(i, j, n, hf, eq)If the iterators return an lvalue the value_type must be CopyConstructible.
-                                 If the iterators return an rvalue the value_type must be MoveConstructible.
    a_uniq.insert(t)The value_type must be CopyConstructible.
    a_uniq.insert(rv)The key_type and the mapped_type (if it exists) must be MoveConstructible.
    a_eq.insert(t)The value_type must be CopyConstructible.
    a_eq.insert(rv)The key_type and the mapped_type (if it exists) must be MoveConstructible.
    a.insert(p, t)The value_type must be CopyConstructible.
    a.insert(p, rv)The key_type and the mapped_type (if it exists) must be MoveConstructible.
    a.insert(i, j)If the iterators return an lvalue the value_type must be CopyConstructible.
-                                        If the iterators return an rvalue the key_type and the mapped_type (if it exists) must be MoveConstructible..
    
-
+
    const_iterator end() const;
+const_iterator cend() const;
+
    
+
    
 
    
+-8- Returns: A terminating iterator that enumerates over all the sub-expressions stored in *this.
 
    
+
    
+
    
 
-
-
-
-
-
    Miscellaneous Requirements
    map[lvalue-key]The key_type must be CopyConstructible.
-                                         The mapped_type must be DefaultConstructible and MoveConstructible.
    map[rvalue-key]The key_type must be MoveConstructible.
-                                         The mapped_type must be DefaultConstructible and MoveConstructible.
    
-
-
    [
-Kona (2007): Howard and Alan to update requirements table in issue with emplace signatures.
-]
    
 
 
 
    [
-Bellevue: This should be handled as part of the concepts work.
+Kona (2007): Voted to adopt proposed wording in
+N2409
+except removing the entry in the table container requirements.  Moved to Review.
 ]
    
 
 
-
-
-
    Proposed resolution:
    
-
-
-
-
    Rationale:
    
 
    [
-post San Francisco:
+Bellevue:  Proposed wording now in the WP.
 ]
    
 
 
-
    
-Solved by
-N2776.
-
    
-
-
-
 
 
 
 
    
-
    707. null pointer constant for exception_ptr
    
-
    Section: 18.8.5 [propagation] Status: NAD
- Submitter: Jens Maurer Opened: 2007-07-20  Last modified: 2008-02-25
    
-
    View other active issues in [propagation].
    
-
    View all other issues in [propagation].
    
-
    View all issues with NAD status.
    
+
    647. Inconsistent regex_search params
    
+
    Section: 28.11.3 [re.alg.search] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2007-02-26  Last modified: 2007-07-26
    
+
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
-
-
    
-From the Toronto Core wiki:
-
    
-
 
    
-What do you mean by "null pointer constant"? How do you guarantee that
-exception_ptr() == 1 doesn't work?  Do you even want to prevent that?
-What's the semantics?  What about void *p = 0; exception_ptr() == p?
-Maybe disallow those in the interface, but how do you do that with
-portable C++? Could specify just "make it work".
+28.11.3 [re.alg.search]/5 declares
 
    
 
-
    
-Peter's response:
-
    
+
    template <class iterator, class charT, class traits>
+bool regex_search(iterator first, iterator last,
+                  const basic_regex<charT, traits>& e,
+                  regex_constants::match_flag_type flags =
+                      regex_constants::match_default);
+
    
 
 
    
-null pointer constant as defined in 4.10 [conv.ptr]. Intent is "just make it
-work", can be implemented as assignment operator taking a unique pointer
-to member, as in the unspecified bool type idiom.
+where it's not explained, which iterator category
+the parameter iterator belongs to. This is inconsistent
+to the preceding declaration in the synopsis section
+28.4 [re.syn], which says:
 
    
 
-
    [
-Bellevue:
-]
    
+
    template <class BidirectionalIterator, class charT, class traits>
+bool regex_search(BidirectionalIterator first, BidirectionalIterator last,
+                  const basic_regex<charT, traits>& e,
+                  regex_constants::match_flag_type flags =
+                      regex_constants::match_default);
+
    
 
 
-
    
-
    
-Original implementation was possible using the "unspecified-null-pointer" idiom, similar to unspecified-bool.
-
    
+
    Proposed resolution:
    
 
    
-Even simpler now with nullptr_t.
+In 28.11.3 [re.alg.search]/5 replace all three occurences of param "iterator" with
+"BidirectionalIterator"
 
    
+
+
    template <class iterator BidirectionalIterator, class charT, class traits>
+  bool regex_search(iterator BidirectionalIterator first, iterator BidirectionalIterator last, 
+                    const basic_regex<charT, traits>& e, 
+                    regex_constants::match_flag_type flags = 
+                      regex_constants::match_default);
+
    
 
    
-NAD Rationale : null pointer constant is a perfectly defined term, and
-while API is clearly implementable there is no need to spell out
-implementation details.
+-6- Effects: Behaves "as if" by constructing an object what of
+type match_results<iterator
+BidirectionalIterator> and then returning the result
+of regex_search(first, last, what, e, flags).
 
    
 
    
 
 
-
-
    Proposed resolution:
    
-
    
-
    
+
    Rationale:
    
+Applied to working paper while issue was still in New status.
 
 
 
 
 
 
    
-
    717. Incomplete valarray::operator[] specification in [valarray.access]
    
-
    Section: 26.6.2.3 [valarray.access] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2007-08-27  Last modified: 2008-09-22
    
-
    View all other issues in [valarray.access].
    
+
    648. regex_iterator c'tor needs clarification/editorial fix
    
+
    Section: 28.12.1.1 [re.regiter.cnstr] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2007-03-03  Last modified: 2007-07-02
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-Since the return type of valarray's operator[] const overload has been
-changed to const T& as described in 389 several paragraphs of
-the section 26.6.2.3 [valarray.access] are now
-incompletely
-specified, because many requirements and guarantees should now also
-apply to the const overload. Most notably, the address and reference
-guarantees should be extended to the const overload case.
-
    
-
-
-
    Proposed resolution:
    
-
    
-Change 26.6.2.3 [valarray.access]:
+In 28.12.1.1 [re.regiter.cnstr]/2 the effects paragraph starts with:
 
    
 
 
    
 
    
--1- When applied to a constant array, the subscript operator returns a
-reference to the corresponding element of the array. When applied to a
-non-constant array, tThe subscript operator returns a
-reference to the corresponding element of the array.
-
    
+Effects: Initializes begin and end to point to the beginning and the
+end of the target sequence, sets pregex to &re, sets flags to f,[..]
+
    
 
 
    
--3- The expression &a[i+j] == &a[i] + j evaluates as true for all size_t i
-and size_t j such that i+j is less 
-than the length of the non-constant array a.
+There are two issues with this description:
 
    
 
-
    
--4- Likewise, the expression &a[i] != &b[j] evaluates
-as true for any two non-constant arrays a and
-b and for any size_t i and size_t j such that
-i is less than the length of a and j is less
-than the length of b. This property indicates an absence of
-aliasing and may be used to advantage by optimizing
-compilers.281)
-
    
+
      
+
    1. 
+The meaning of very first part of this quote is unclear, because
+there is no target sequence provided, instead there are given two
+parameters a and b, both of type BidirectionalIterator. The mentioned
+part does not explain what a and b represent.
+
      2. 
+
    2. 
+There does not exist any parameter f, but instead a parameter
+m in the constructor declaration, so this is actually an editorial
+fix.
+
      3. 
+
    
 
+
+
    Proposed resolution:
    
 
    
--5- The reference returned by the subscript operator for an non-constant array is guaranteed to be valid until
-the member function resize(size_t, T) (26.5.2.7) is called for that array or until the lifetime 
-of that array ends, whichever happens first.
+In 28.12.1.1 [re.regiter.cnstr]/2 change the above quoted part by
 
    
 
-
    
-
+
    
+Effects: Initializes begin and end to point to
+the beginning and the end of the target sequence designated by the
+iterator range [a, b), sets pregex to
+&re, sets flags to f
+m, then calls regex_search(begin, end, match,
+*pregex, flags). If this call returns false the
+constructor sets *this to the end-of-sequence iterator.
+
    
 
 
 
 
 
 
    
-
    724. DefaultConstructible is not defined
    
-
    Section: X [utility.arg.requirements] Status: NAD Editorial
- Submitter: Pablo Halpern Opened: 2007-09-12  Last modified: 2008-09-23
    
-
    View all other issues in [utility.arg.requirements].
    
+
    649. Several typos in regex_token_iterator constructors
    
+
    Section: 28.12.2.1 [re.tokiter.cnstr] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2007-03-03  Last modified: 2007-07-02
    
+
    View all other issues in [re.tokiter.cnstr].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-The DefaultConstructible requirement is referenced in
-several places in the August 2007 working draft
-N2369,
-but is not defined anywhere.
-
    
-
-
    [
-Bellevue:
-]
    
-
-
-
    
-
    
-Walking into the default/value-initialization mess...
-
    
-
    
-Why two lines? Because we need both expressions to be valid.
-
    
-
    
-AJM not sure what the phrase "default constructed" means. This is
-unfortunate, as the phrase is already used 24 times in the library!
+In 28.12.2.1 [re.tokiter.cnstr]/1+2 both the constructor declaration
+and the following text shows some obvious typos:
 
    
 
    
-Example: const int would not accept first line, but will accept the second.
-
    
-
    
-This is an issue that must be solved by concepts, but we might need to solve it independantly first.
+1) The third constructor form is written as
 
    
+
    template <std::size_t N>
+  regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b, 
+                       const regex_type& re, 
+                       const int (&submatches)[R], 
+                       regex_constants::match_flag_type m = 
+                         regex_constants::match_default);
+
    
+
 
    
-It seems that the requirements are the syntax in the proposed first
-column is valid, but not clear what semantics we need.
+where the dimensions of submatches are specified by an
+unknown value R, which should be N.
 
    
 
    
-A table where there is no post-condition seems odd, but appears to sum up our position best.
+2) Paragraph 2 of the same section says in its last sentence:
 
    
+
+
    
+The third constructor initializes the member subs to hold a
+copy of the sequence of integer values pointed to by the iterator range
+[&submatches, &submatches + R).
+
    
+
 
    
-At a minimum an object is declared and is destuctible.
+where again R must be replaced by N.
 
    
+
 
    
-Move to open, as no-one happy to produce wording on the fly.
+3) Paragraph 3 of the same section says in its first sentence:
 
    
-
    
 
+
    
+Each constructor then sets N to 0, and
+position to position_iterator(a, b, re, f).
+
    
 
-
    Proposed resolution:
    
 
    
-In section X [utility.arg.requirements], before table 33, add the
-following table:
+where a non-existing parameter "f" is mentioned, which must be
+replaced
+by the parameter "m".
 
    
 
-
    Table 33: DefaultConstructible requirements
    
 
-
    
-
-
- 
-  
-  
- 
- 
-  
-  
- 
-
    
-  
    expression
    
-      		
-  
    post-condition
    
-  
    
-  
    T
-  t;
    
-  T()
    
-      		
-  
    T
-  is default constructed.
    
-  
    
-
-
    
-
-
-
-
    Rationale:
    
-
    [
-San Francisco:
-]
    
-
-
    
-We believe concepts will solve this problem
-(N2774).
-
    
-
-
-
-
-
-
    
-
    725. Optional sequence container requirements column label
    
-
    Section: 23.2.3 [sequence.reqmts] Status: NAD Editorial
- Submitter: David Abrahams Opened: 2007-09-16  Last modified: 2008-09-22
    
-
    View other active issues in [sequence.reqmts].
    
-
    View all other issues in [sequence.reqmts].
    
-
    View all issues with NAD Editorial status.
    
-
    Discussion:
    
+
    Proposed resolution:
    
 
    
-Table 90: (Optional sequence container operations) states the
-"assertion note pre/post-condition" of operator[] to be
+Change 28.12.2.1 [re.tokiter.cnstr]/1:
 
    
-
-
    *(a.begin() + n)
+
    template <std::size_t N>
+  regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b, 
+                       const regex_type& re, 
+                       const int (&submatches)[R N], 
+                       regex_constants::match_flag_type m = 
+                         regex_constants::match_default);
 
    
 
 
    
-Surely that's meant to be "operational semantics?"
+Change 28.12.2.1 [re.tokiter.cnstr]/2:
 
    
 
+
    
+Effects: The first constructor initializes the member
+subs to hold the single value submatch. The second
+constructor initializes the member subs to hold a copy of the
+argument submatches. The third constructor initializes the
+member subs to hold a copy of the sequence of integer values
+pointed to by the iterator range [&submatches, &submatches +
+R N).
+
    
 
+
    
+Change 28.12.2.1 [re.tokiter.cnstr]/3:
+
    
 
-
    Proposed resolution:
    
-
    
-
-
-
-
-
-
    Table 90: Optional sequence container operations
    expression return type assertion/note
    pre/post-condition
     operational semantics    		 container
    
-
    
+
    
+Each constructor then sets N to 0, and
+position to position_iterator(a, b, re, f
+m). If position is not an end-of-sequence
+iterator the constructor sets result to the address of the
+current match. Otherwise if any of the values stored in subs is
+equal to -1 the constructor sets *this to a suffix
+iterator that points to the range [a, b), otherwise the
+constructor sets *this to an end-of-sequence iterator.
+
    
 
 
 
@@ -13007,401 +14320,521 @@ Surely that's meant to be "operational semantics?"
 
 
 
    
-
    729. Problem in [rand.req.eng]/3
    
-
    Section: X [rand.req.eng] Status: NAD
- Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
    
-
    View all other issues in [rand.req.eng].
    
+
    653. Library reserved names
    
+
    Section: 1.2 [intro.refs] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2007-03-08  Last modified: 2008-02-25
    
+
    View all other issues in [intro.refs].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-The 3rd table row in X [rand.req.eng]/3 requires random number engines to accept any 
-arithmetic type as a seed, which is then casted to the engine's result_type and subsequently 
-used for seeding the state of the engine. The requirement stated as "Creates an engine with 
-initial state determined by static_cast<X::result_type>(s)" forces random number engines 
-to either use a seeding method that completely depends on the result_type (see the discussion 
-of seeding for the mersenne_twister_engine in point T2 above) or at least to throw away "bits 
-of randomness" in the seed value if the result_type is smaller than the seed type. This seems 
-to be inappropriate for many modern random number generators, in particular F2-linear or 
-cryptographic ones, which operate on an internal bit array that in principle is independent of the 
-type of numbers returned.
 
    
-
+
    
 
    
-Posible resolution: I propose to change the wording to a version similar to "Creates an 
-engine with initial state determined by static_cast<UintType>(s), where UintType is an 
-implementation specific unsigned integer type."
+1.2 [intro.refs] Normative references
 
    
 
 
    
-Additionally, the definition of s in X [rand.req.eng]/1 c) could be restricted to unsigned integer types.
+The following standards contain provisions which, through reference in
+this text, constitute provisions of this Interna- tional Standard. At
+the time of publication, the editions indicated were valid. All
+standards are subject to revision, and parties to agreements based on
+this International Standard are encouraged to investigate the
+possibility of applying the most recent editions of the standards
+indicated below. Members of IEC and ISO maintain registers of currently
+valid International Standards.
 
    
 
+
      
+
    • Ecma International, ECMAScript Language Specification, Standard
+Ecma-262, third edition, 1999.
      • 
+
    • ISO/IEC 2382 (all parts), Information technology - Vocabulary
      • 
+
    • ISO/IEC 9899:1990, Programming languages - C
      • 
+
    • ISO/IEC 9899/Amd.1:1995, Programming languages - C, AMENDMENT 1: C
+Integrity
      • 
+
    • ISO/IEC 9899:1999, Programming languages - C
      • 
+
    • ISO/IEC 9899:1999/Cor.1:2001 Programming languages - C
      • 
+
    • ISO/IEC 9899:1999/Cor.2:2004 Programming languages - C
      • 
+
    • ISO/IEC 9945:2003, Information Technology-Portable Operating System
+Interface (POSIX)
      • 
+
    • ISO/IEC 10646-1:1993 Information technology - Universal Multiple-Octet
+Coded Character Set (UCS) - Part 1: Architecture and Basic Multilingual
+Plane
      • 
+
    
+
    
+
 
    
-Similarly, the type of the seed in X [rand.req.adapt]/3 e) could be left unspecified.
+I'm not sure how many of those reserve naming patterns that might affect
+us, but I am equally sure I don't own a copy of any of these to check!
 
    
-
 
    
-See N2424
-for further discussion.
+The point is to list the reserved naming patterns, rather than the
+individual names themselves - although we may want to list C keywords
+that are valid identifiers in C++ but likely to cause trouble in shared
+headers (e.g. restrict)
 
    
 
 
    [
-Stephan Tolksdorf adds pre-Bellevue:
+Kona (2007): Recommend NAD.  No one has identified a specific defect, just the possibility of one.
 ]
    
 
 
-
    
-
    
-In reply to the discussion in
-N2424
-regarding this issue:
-
    
-
    
-The descriptions of all engines and engine adaptors given in sections
-26.5.3 [rand.eng] and 26.5.4 [rand.adapt] already specify the concrete
-types of the integer arguments for seeding. Hence, relaxing the general
-requirement in X [rand.req.eng] would not affect portability and
-reproducibility of the standard library. Furthermore, it is not clear to
-me what exactly the guarantee "with initial state determined by
-static_cast<X::result_type>(s)" is useful for. On the other hand,
-relaxing the requirement would allow developers to implement  other
-random number engines that do not have to cast all arithmetic seed
-arguments to their result_types.
-
    
-
    
-
 
    [
-Bellevue:
+Post-Kona: Alisdair request Open. A good example of the problem was a
+discussion of the system error proposal, where it was pointed out an all-caps
+identifier starting with a capital E conflicted with reserved macro names for
+both Posix and C.  I had absolutely no idea of this rule, and suspect I was
+not the only one in the room.
    
+
    
+Resolution will require someone with access to all the listed documents to
+research their respective name reservation rules, or people with access to
+specific documents add their rules to this issue until the list is complete.
 ]
    
 
 
-
    
-Propose close NAD for the reasons given in N2424.
-
    
+
    [
+Bellevue: Wording is aleady present in various standards, and no-one has come forward with wording.
+Suggest a formal paper rather than a defect report is the correct way to proceed.
+]
    
 
 
 
 
 
    Proposed resolution:
    
-
    
-See N2424
-for further discussion.
-
    
 
-
    [
-Stephan Tolksdorf adds pre-Bellevue:
-]
    
 
 
-
    
+
+
+
    
+
    656. Typo in subtract_with_carry_engine declaration
    
+
    Section: 26.5.1 [rand.synopsis] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2007-03-08  Last modified: 2007-07-02
    
+
    View all other issues in [rand.synopsis].
    
+
    View all issues with NAD Editorial status.
    
+
    Discussion:
    
 
    
-Change row 3 of table 105 "Random number engine requirements" in X [rand.req.eng]/3
+26.5.1 [rand.synopsis] the header <random> synopsis
+contains an unreasonable closing curly brace inside the
+subtract_with_carry_engine declaration.
 
    
 
-
    
-Creates an engine with initial state determined by
-static_cast<X::result_type>(s)
-
    
 
+
    Proposed resolution:
    
 
    
-Similarly, change X [rand.req.adapt]/3 e)
+Change the current declaration in 26.5.1 [rand.synopsis]
 
    
 
-
    
-When X::X is invoked with an X::result_type value s
-of arithmetic type (3.9.1), ...
-
    
+
    template <class UIntType, size_t w}, size_t s, size_t r>
+class subtract_with_carry_engine;
+
    
 
-
    
 
+
    [
+Pete: Recommends editorial.
+]
    
 
 
 
 
 
 
    
-
    730. Comment on [rand.req.adapt]/3 e)
    
-
    Section: X [rand.req.adapt] Status: NAD
- Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
    
+
    657. unclear requirement about header inclusion
    
+
    Section: 17.6.2.2 [using.headers] Status: NAD
+ Submitter: Gennaro Prota Opened: 2007-03-14  Last modified: 2007-10-10
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
 
    
-If an engine adaptor is invoked with an argument of type seed_seq, then all base 
-engines are specified to be seeded with this seed_seq. As seed_seq's randomization method is 
-qualified as constant, this procedure will ef fectively initialize all base engines with the same seed 
-(though the resulting state might still dif fer to a certain degree if the engines are of different types). 
-It is not clear whether this mode of operation is in general appropriate, hence -- as far as the 
-stated requirements are of general nature and not just specific to the engine adaptors provided by 
-the library -- it might be better to leave the behaviour unspecified, since the current definition of 
-seed_seq does not allow for a generally satisfying specification.
+17.6.2.2 [using.headers] states:
 
    
 
-
    
-Posssible resolution: [As above]
-
    
+
    
+A translation unit shall include a header only outside of any
+external declaration or definition, [...]
+
    
 
 
    
-See N2424
-for further discussion.
+I see three problems with this requirement:
 
    
 
-
    [
-Bellevue:
-]
    
-
-
-
    
-Close NAD for the reasons given in N2424.
-
    
-
-
-
-
    Proposed resolution:
    
-
    
-See N2424
-for the proposed resolution.
+
      
+
    1. The C++ standard doesn't define what an "external declaration" or
+an "external definition" are (incidentally the C99 standard does, and
+has a sentence very similar to the above regarding header inclusion).
+
      
+I think the intent is that the #include directive shall lexically
+appear outside *any* declaration; instead, when the issue was pointed
+out on comp.std.c++ at least one poster interpreted "external
+declaration" as "declaration of an identifier with external linkage".
+If this were the correct interpretation, then the two inclusions below
+would be legal:
 
      
+
        // at global scope
+  static void f()
+  {
+# include <cstddef>
+  }
 
-
-
-
-
-
      
-
      731. proposal for a customizable seed_seq
      
-
      Section: 26.5.7.1 [rand.util.seedseq] Status: NAD
- Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
      
-
      View all other issues in [rand.util.seedseq].
      
-
      View all issues with NAD status.
      
-
      Discussion:
      
-
      
-The proper way to seed random number engines seems to be the most frequently 
-discussed issue of the 26.5 [rand] proposal. While the new seed_seq approach is already rather 
-general and probably sufficient for most situations, it is unlikely to be optimal in every case (one 
-problem was pointed out in point T5 above). In some situations it might, for instance, be better to 
-seed the state with a cryptographic generator. 
-
      
+  static void g()
+  {
+# include <stddef.h>
+  }
+
      
 
      
-In my opinion this is a pretty strong argument for extending the standard with a simple facility to 
-customize the seeding procedure. This could, for example, be done with the following minimal 
-changes:
-
      
+(note that while the first example is unlikely to compile correctly,
+the second one may well do)
+
      2. 
 
-
      
-Possible resolution:
+
    2. as the sentence stands, violations will require a diagnostic; is
+this the intent? It was pointed out on comp.std.c++ (by several
+posters) that at least one way to ensure a diagnostic exists:
 
      
+
      
+   [If there is an actual file for each header,] one simple way
+   to implement this would be to insert a reserved identifier
+   such as __begin_header  at the start of each standard header.
+   This reserved identifier would be ignored for all other
+   purposes, except that, at the appropriate point in phase 7, if
+   it is found inside an external definition, a diagnostic is
+   generated. There's many other similar ways to achieve the same
+   effect.
+   
      
+
                                       --James Kuyper, on comp.std.c++
+
      3. 
 
-
        
-
      1. 
-Turn the interface specification of 26.5.7.1 [rand.util.seedseq]/2 into a "SeedSeq" requirement, where the 
-exact behaviour of the constructors and the randomize method are left unspecified and where the
-const qualification for randomize is removed. Classes implementing this interface are additionally 
-required to specialize the traits class in c).
-
        2. 
-
      2. 
-Provide the class seed_seq as a default implementation of the SeedSeq interface.
-
        3. 
-
      3. 
-
        
-Supplement the seed_seq with a traits class
+
      4. is the term "header" meant to be limited to standard headers?
+Clause 17 is all about the library, but still the general question is
+interesting and affects one of the points in the explicit namespaces
+proposal (n1691):
 
        
-
        template <typename T> 
-struct is_seed_seq { static const bool value = false; }
-
        
-
        and the specialization
        
-
        template <> 
-struct is_seed_seq<seed_seq> { static const bool value = true; }
+
        
+    Those seeking to conveniently enable argument-dependent
+    lookups for all operators within an explicit namespace
+    could easily create a header file that does so:
+
            namespace mymath::
+    {
+        #include "using_ops.hpp"
+    }
 
        
-
        which users can supplement with further specializations.
        
-
        5. 
-
      5. 
-Change X [rand.req.eng]/1 d) to "q is an lvalue of a type that fulfils the SeedSeq requirements", and 
-modify the constructors and seed methods in 26.5.3 [rand.eng] appropriately (the actual implementation 
-could be done using the SFINAE technique).
 
        6. 
 
      
 
-
      [
-Bellevue:
-]
      
-
-
-
      
-See N2424. Close NAD but note that "conceptizing" the library may cause
-this problem to be solved by that route.
-
      
-
 
 
      Proposed resolution:
      
 
      
-See N2424
-for the proposed resolution.
 
      
 
 
+
      Rationale:
      
+We believe that the existing language does not cause any real confusion
+and any new formulation of the rules that we could come up with are
+unlikely to be better than what's already in the standard.
+
+
 
 
 
 
      
-
      732. Defect in [rand.dist.samp.genpdf]
      
-
      Section: X [rand.dist.samp.genpdf] Status: NAD Editorial
- Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2009-03-09
      
-
      View all other issues in [rand.dist.samp.genpdf].
      
+
      658. Two unspecified function comparators in [function.objects]
      
+
      Section: 20.7 [function.objects] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2007-03-19  Last modified: 2007-08-05
      
+
      View all other issues in [function.objects].
      
 
      View all issues with NAD Editorial status.
      
-
      Duplicate of: 795
      
 
      Discussion:
      
 
      
-X [rand.dist.samp.genpdf] describes the interface for a distribution template that is 
-meant to simulate random numbers from any general distribution given only the density and the 
-support of the distribution. I'm not aware of any general purpose algorithm that would be capable 
-of correctly and efficiently implementing the described functionality. From what I know, this is 
-essentially an unsolved research problem. Existing algorithms either require more knowledge 
-about the distribution and the problem domain or work only under very limited circumstances. 
-Even the state of the art special purpose library UNU.RAN does not solve the problem in full 
-generality, and in any case, testing and customer support for such a library feature would be a 
-nightmare.
-
      
-
-
      
-Possible resolution: For these reasons, I propose to delete section X [rand.dist.samp.genpdf].
+The header <functional> synopsis in 20.7 [function.objects]
+contains the following two free comparison operator templates
+for the function class template
 
      
 
-
      [
-Bellevue:
-]
      
-
+
      template<class Function1, class Function2>
+void operator==(const function<Function1>&, const function<Function2>&);
+template<class Function1, class Function2>
+void operator!=(const function<Function1>&, const function<Function2>&);
+
      
 
-
      
-
      
-Disagreement persists.
-
      
-
      
-Objection to this issue is that this function takes a general functor.
-The general approach would be to normalize this function, integrate it,
-and take the inverse of the integral, which is not possible in general.
-An example function is sin(1+n*x) -- for any spatial frequency that the
-implementor chooses, there is a value of n that renders that choice
-arbitrarily erroneous.
-
      
-
      
-Correction: The formula above should instead read 1+sin(n*x).
-
      
 
      
-Objector proposes the following possible compromise positions:
+which are nowhere described. I assume that they are relicts before the
+corresponding two private and undefined member templates in the function
+template (see 20.7.16.2 [func.wrap.func] and  [func.wrap.func.undef]) have been introduced. The original free
+function templates should be removed, because using an undefined entity
+would lead to an ODR violation of the user.
 
      
-
        
-
      • 
-rand.dist.samp.genpdf takes an number of points so that implementor need not guess.
-
        • 
-
      • replace rand.disk.samp.genpdf with an extension to either or both
-of the discrete functions to take arguments that take a functor and
-number of points in place of the list of probabilities. Reference
-issues 793 and 794.
-
        • 
-
      
-
      
-
 
 
 
      Proposed resolution:
      
 
      
-See N2813
-for the proposed resolution.
+Remove the above mentioned two function templates from
+the header <functional> synopsis (20.7 [function.objects])
 
      
 
+
      template<class Function1, class Function2>
+void operator==(const function<Function1>&, const function<Function2>&);
+template<class Function1, class Function2>
+void operator!=(const function<Function1>&, const function<Function2>&);
+
      
+
+
 
 
      Rationale:
      
-Addressed by
-N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
+Fixed by
+N2292
+Standard Library Applications for Deleted Functions.
 
 
 
 
 
 
      
-
      733. Comment on [rand.req.dist]/9
      
-
      Section: X [rand.req.dist] Status: NAD
- Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
      
+
      662. Inconsistent handling of incorrectly-placed thousands separators
      
+
      Section: 22.4.2.1.2 [facet.num.get.virtuals] Status: NAD
+ Submitter: Cosmin Truta Opened: 2007-04-05  Last modified: 2007-07-25
      
+
      View other active issues in [facet.num.get.virtuals].
      
+
      View all other issues in [facet.num.get.virtuals].
      
 
      View all issues with NAD status.
      
 
      Discussion:
      
 
      
-The requirement "P shall have a declaration of the form typedef X distribution_- 
-type" effectively makes the use of inheritance for implementing distributions very inconvenient, 
-because the child of a distribution class in general will not satisfy this requirement. In my opinion 
-the benefits of having a typedef in the parameter class pointing back to the distribution class are 
-not worth the hassle this requirement causes. [In my code base I never made use of the nested 
-typedef but on several occasions could have profited from being able to use simple inheritance for 
-the implementation of a distribution class.]
+From Section 22.4.2.1.2 [facet.num.get.virtuals], paragraphs 11 and 12, it is implied
+that the value read from a stream must be stored
+even if the placement of thousands separators does not conform to the
+grouping() specification from the numpunct facet.
+Since incorrectly-placed thousands separators are flagged as an extraction
+failure (by the means of failbit), we believe it is better not
+to store the value. A consistent strategy, in which any kind of extraction
+failure leaves the input item intact, is conceptually cleaner, is able to avoid
+corner-case traps, and is also more understandable from the programmer's point
+of view.
 
      
-
 
      
-Proposed resolution: I propose to drop this requirement.
+Here is a quote from "The C++ Programming Language (Special Edition)"
+by B. Stroustrup (Section D.4.2.3, pg. 897):
+
      
+
      
+"If a value of the desired type could not be read, failbit is set in r.
+[...] An input operator will use r to determine how to set the state of its
+stream. If no error was encountered, the value read is assigned through v;
+otherwise, v is left unchanged."
+
      
+
      
+This statement implies that rdstate() alone is sufficient to
+determine whether an extracted value is to be assigned to the input item
+val passed to do_get. However, this is in disagreement
+with the current C++ Standard. The above-mentioned assumption is true in all
+cases, except when there are mismatches in digit grouping. In the latter case,
+the parsed value is assigned to val, and, at the same time, err
+is assigned to ios_base::failbit (essentially "lying" about the
+success of the operation). Is this intentional? The current behavior raises
+both consistency and usability concerns.
+
      
+
      
+Although digit grouping is outside the scope of scanf (on which
+the virtual methods of num_get are based), handling of grouping
+should be consistent with the overall behavior of scanf. The specification of
+scanf makes a distinction between input failures and matching
+failures, and yet both kinds of failures have no effect on the input items
+passed to scanf. A mismatch in digit grouping logically falls in
+the category of matching failures, and it would be more consistent, and less
+surprising to the user, to leave the input item intact whenever a failure is
+being signaled.
+
      
+
      
+The extraction of bool is another example outside the scope of
+scanf, and yet consistent, even in the event of a successful
+extraction of a long but a failed conversion from
+long to bool.
+
      
+
      
+Inconsistency is further aggravated by the fact that, when failbit is set,
+subsequent extraction operations are no-ops until failbit is
+explicitly cleared. Assuming that there is no explicit handling of
+rdstate() (as in cin>>i>>j) it is
+counter-intuitive to be able to extract an integer with mismatched digit
+grouping, but to be unable to extract another, properly-formatted integer
+that immediately follows.
+
      
+
      
+Moreover, setting failbit, and selectively assigning a value to
+the input item, raises usability problems. Either the strategy of
+scanf (when there is no extracted value in case of failure), or
+the strategy of the strtol family (when there is always an
+extracted value, and there are well-defined defaults in case of a failure) are
+easy to understand and easy to use. On the other hand, if failbit
+alone cannot consistently make a difference between a failed extraction, and a
+successful but not-quite-correct extraction whose output happens to be the same
+as the previous value, the programmer must resort to implementation tricks.
+Consider the following example:
+
      
+
          int i = old_i;
+    cin >> i;
+    if (cin.fail())
+        // can the value of i be trusted?
+        // what does it mean if i == old_i?
+        // ...
+
      
+
      
+Last but not least, the current behvaior is not only confusing to the casual
+reader, but it has also been confusing to some book authors. Besides
+Stroustrup's book, other books (e.g. "Standard C++ IOStreams and Locales" by
+Langer and Kreft) are describing the same mistaken assumption. Although books
+are not to be used instead of the standard reference, the readers of these
+books, as well as the people who are generally familiar to scanf,
+are even more likely to misinterpret the standard, and expect the input items
+to remain intact when a failure occurs.
 
      
-
-
      [
-Bellevue:
-]
      
 
 
+
      Proposed resolution:
      
+
+
      
+Change 22.4.2.1.2 [facet.num.get.virtuals]:
+
      
+
 
      
-Close NAD for the reasons given in N2424. In practice it is not inconvenient to meet these requirements.
+
      
+Stage 3: The result of stage 2 processing can be one of
+
      
+
        
+
      • A sequence of chars has been accumulated in stage 2 that is converted (according to the rules of scanf) to a value of the type of val.  This value is stored in val and ios_base::goodbit is stored in err.
        • 
+
+
      • The sequence of chars accumulated in stage 2 would have caused scanf to report an input failure. ios_base::failbit is assigned to err.
        • 
+
      
+
      
+In the first case, Ddigit grouping is checked.  That is, the positions of discarded separators is examined for consistency with use_facet<numpunct<charT> >(loc).grouping().  If they are not consistent then ios_base::failbit is assigned to err.  Otherwise, the value that was converted in stage 2 is stored in val and ios_base::goodbit is stored in err.
+
      
 
      
 
 
+
      Rationale:
      
+post-Toronto: Changed from New to NAD at the request of the author.  The preferred solution of
+N2327
+makes this resolution obsolete.
+
+
+
+
+
+
      
+
      663. Complexity Requirements
      
+
      Section: 17.5.1.4 [structure.specifications] Status: NAD
+ Submitter: Thomas Plum Opened: 2007-04-16  Last modified: 2009-05-01
      
+
      View all other issues in [structure.specifications].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+17.5.1.4 [structure.specifications] para 5 says
+
      
+
+
      
+-5- Complexity requirements specified in the library
+clauses are upper bounds, and implementations that provide better
+complexity guarantees satisfy the requirements.
+
      
+
+
      
+The following
+objection has been raised:
+
      
+
+
      
+The library clauses suggest general
+guidelines regarding complexity, but we have been unable to discover
+any absolute hard-and-fast formulae for these requirements. Unless
+or until the Library group standardizes specific hard-and-fast
+formulae, we regard all the complexity requirements as subject to a
+"fudge factor" without any intrinsic upper bound.
+
      
+
+
      
+[Plum ref
+_23213Y31 etc]
+
      
+
 
 
      Proposed resolution:
      
 
      
-See N2424
-for the proposed resolution.
 
      
 
 
+
      Rationale:
      
+Kona (2007): No specific instances of underspecification have been
+identified, and big-O notation always involves constant factors.
+
+
 
 
 
 
      
-
      735. Unfortunate naming
      
-
      Section: 26.5.8.2.2 [rand.dist.bern.bin], 26.5.8.2.4 [rand.dist.bern.negbin] Status: NAD
- Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
      
+
      667. money_get's widened minus sign
      
+
      Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: NAD
+ Submitter: Thomas Plum Opened: 2007-04-16  Last modified: 2009-07-13
      
+
      View other active issues in [locale.money.get.virtuals].
      
+
      View all other issues in [locale.money.get.virtuals].
      
 
      View all issues with NAD status.
      
 
      Discussion:
      
 
      
-In my opinion the choice of name for the t parameter of the binomial_distribution
-is very unfortunate. In virtually every internet reference, book and software implementation 
-this parameter is called n instead, see for example Wikipedia, Mathworld, Evans et al. (1993) 
-Statistical Distributions, 2nd E., Wiley, p. 38, the R statistical computing language, p. 926, 
-Mathematica and Matlab.
+22.4.6.1.2 [locale.money.get.virtuals], para 1 says:
 
      
 
+
      
+The result is returned as an integral value
+stored in units or as a sequence of digits possibly preceded by a
+minus sign (as produced by ct.widen(c) where c is '-' or in the range
+from '0' through '9', inclusive) stored in digits.
+
      
+
 
      
-Similarly, the choice of k for the parameter of the negative binomial distributions is rather unusual. 
-The most common choice for the negative binomial distribution seems to be r instead.
+The following
+objection has been raised:
 
      
 
+
      
+Some implementations interpret this to mean that a facet derived from
+ctype<wchar_t> can provide its own member do_widen(char)
+which produces e.g. L'@' for the "widened" minus sign, and that the
+'@' symbol will appear in the resulting sequence of digits.  Other
+implementations have assumed that one or more places in the standard permit the
+implementation to "hard-wire" L'-' as the "widened" minus sign.  Are
+both interpretations permissible, or only  one?
+
      
+
 
      
-Choosing unusual names for the parameters causes confusion among users and makes the 
-interface unnecessarily inconvenient to use.
+[Plum ref _222612Y14]
 
      
 
 
      
-Possible resolution: For these reasons, I propose to change the name of the respective parameters
-to n and r.
+Furthermore: if ct.widen('9') produces L'X' (a non-digit), does a
+parse fail if a '9' appears in the subject string? [Plum ref _22263Y33]
 
      
 
 
      [
-Bellevue:
+Kona (2007): Bill and Dietmar to provide proposed wording.
+]
      
+
+
+
      [
+post Bellevue: Bill adds:
 ]
      
 
 
 
      
-In N2424. NAD It has been around for a while. It is hardly universal,
-there is prior art, and this would confuse people.
+The Standard is clear that the minus sign stored in digits is ct.widen('-').
+The subject string must contain characters c in the set [-0123456789]
+which are translated by ct.widen(c) calls before being stored in digits;
+the widened characters are not relevant to the parsing of the subject string.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with Bill's comment above,
+in line with the first of the interpretations offered in the issue.
+Move to NAD.
 
      
 
 
 
      Proposed resolution:
      
 
      
-See N2424
-for the proposed resolution.
 
      
 
 
@@ -13409,446 +14842,461 @@ for the proposed resolution.
 
 
 
      
-
      736. Comment on [rand.dist.samp.discrete]
      
-
      Section: 26.5.8.5.1 [rand.dist.samp.discrete] Status: NAD
- Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
      
-
      View all other issues in [rand.dist.samp.discrete].
      
+
      669. Equivalent postive and negative signs in money_get
      
+
      Section: 22.4.6.1.2 [locale.money.get.virtuals] Status: NAD
+ Submitter: Thomas Plum Opened: 2007-04-16  Last modified: 2009-07-13
      
+
      View other active issues in [locale.money.get.virtuals].
      
+
      View all other issues in [locale.money.get.virtuals].
      
 
      View all issues with NAD status.
      
 
      Discussion:
      
-
        
-
      1. 
-The specification for discrete_distribution requires the member probabilities()
-to return a vector of standardized probabilities, which forces the implementation every time to 
-divide each probability by the sum of all probabilities, as the sum will in practice almost never be 
-exactly 1.0. This is unnecessarily inef ficient as the implementation would otherwise not need to 
-compute the standardized probabilities at all and could instead work with the non-standardized 
-probabilities and the sum. If there was no standardization the user would just get back the 
-probabilities that were previously supplied to the distribution object, which to me seems to be the 
-more obvious solution.
-
        2. 
-
      2. 
-The behaviour of discrete_distribution is not specified in case the number of given
-probabilities is larger than the maximum number representable by the IntType.
-
        3. 
-
      
-
 
      
-Possible resolution: I propose to change the specification such that the non-standardized 
-probabilities need to be returned and that an additional requirement is included for the number 
-of probabilities to be smaller than the maximum of IntType.
+22.4.6.1.2 [locale.money.get.virtuals], para 3 sentence 4 says:
 
      
 
-
      [
-Stephan Tolksdorf adds pre-Bellevue:
-]
      
-
+
      
+If the first character of pos is equal to the first character of neg, 
+or if both strings are empty, the result is given a positive sign.
+
      
 
-
      
 
      
-In reply to the discussion in 
-N2424
-of this issue:
+One interpretation is that an input sequence must match either the
+positive pattern or the negative pattern, and then in either event it
+is interpreted as positive.  The following objections has been raised:
 
      
+
+
      
+The input can successfully match only a positive sign, so the negative
+pattern is an unsuccessful match.
+
      
+
 
      
-Rescaled floating-point parameter vectors can not be expected to compare
-equal because of the limited precision of floating-point numbers.
-My proposal would at least guarantee that a parameter
-vector (of type double) passed into the distribution would compare equal
-with the one returned by the probabilities() method. Furthermore, I do
-not understand why "the changed requirement would lead to a significant
-increase in the amount of state in the distribution object". A typical
-implementation's state would increase by exactly one number: the sum of
-all probabilities. The textual representation for serialization would
-not need to grow at all. Finally, the proposed replacement "0 < n <=
-numeric_limits<IntType>::max() + 1" makes the implementation
-unnecessarily complicated, "0 < n <= numeric_limits<IntType>::max()"
-would be better.
+[Plum ref _222612Y34, 222612Y51b]
 
      
-
      
 
 
      [
-Bellevue:
+Bill to provide proposed wording and interpretation of existing wording.
 ]
      
 
 
-
      
-
      
-In N2424. We agree with the observation and the proposed resolution to
-part b). We recommend the wording n > 0 be replaced with 0 < n
-numeric_limits::max() + 1. However, we disagree with part a), as it
-would interfere with the definition of parameters' equality. Further,
-the changed requirement would lead to a significant increase in the
-amount of state of the distribution object.
-
      
+
      [
+2009-05-17 See Howard's comments in related issue 668.
+]
      
+
 
+
      [
+Batavia (2009-05):
+]
      
+
+
      
 
      
-As it stands now, it is convenient, and the changes proposed make it
-much less so.
+This discussion applies equally to issue 668 (q.v.).
+Howard has added examples there,
+and recommends either NAD or a resolution that adds his (or similar) examples
+to the Working Paper.
 
      
-
 
      
-NAD. Part a the current behavior is desirable. Part b, any constructor
-can fail, but the rules under which it can fail do not need to be listed
-here.
+We recommend moving to NAD.
+Anyone who feels strongly about adding the examples
+is invited to submit corresponding wording.
+We further recommend issue 668 be handled identically.
 
      
 
      
 
 
 
      Proposed resolution:
      
 
      
-See N2424
-for the proposed resolution.
 
      
 
-
      [
-Stephan Tolksdorf adds pre-Bellevue:
-]
      
 
 
-
      
-
      
-In 26.5.8.5.1 [rand.dist.samp.discrete]:
-
      
 
-
      
-Proposed wording a):
-
      
 
-
      
+
      
+
      670. money_base::pattern and space
      
+
      Section: 22.4.6.3 [locale.moneypunct] Status: Dup
+ Submitter: Thomas Plum Opened: 2007-04-16  Last modified: 2008-09-22
      
+
      View all issues with Dup status.
      
+
      Duplicate of: 836
      
+
      Discussion:
      
 
      
-Changae in para. 2
+22.4.6.3 [locale.moneypunct], para 2 says:
 
      
 
-
      
-Constructs a discrete_distribution object with n=1 and p0 = w0 = 1
-
      
+
      
+The value space indicates that at least one space is required at 
+that position.
+
      
 
 
      
-and change in para. 5
+The following objection has been raised:
 
      
 
-
      
-Returns: A vector<double> whose size member returns n and whose
-operator[] member returns pk
-the weight wk as a double value
-when invoked with argument k for k = 0,
-..., n-1
-
      
-
-
      
+
      
+Whitespace is optional when matching space. (See 22.4.6.1.2 [locale.money.get.virtuals], para 2.)
+
      
 
 
      
-Proposed wording b):
+[Plum ref _22263Y22]
 
      
 
-
      
-
      
-Change in para. 3:
-
      
+
      [
+Kona (2007): Bill to provide proposed wording. We agree that C++03 is
+ambiguous, and that we want C++0X to say "space" means 0 or more
+whitespace characters on input.
+]
      
 
-
      
-If firstW == lastW, let the sequence w have length n = 1 and consist
-of the single value w0 = 1. Otherwise, [firstW,lastW) shall form a
-sequence w of length n > 0 
-such that 0 < n <= numeric_limits<IntType>::max(),
-and *firstW shall yield a value w0
-convertible to double. [Note: The values wk are commonly known
-as the weights . -- end note]
-
      
 
-
      
 
-
      
+
+
      Proposed resolution:
      
 
 
 
 
 
 
      
-
      737. Comment on [rand.dist.samp.pconst]
      
-
      Section: 26.5.8.5.2 [rand.dist.samp.pconst] Status: NAD
- Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
      
-
      View all other issues in [rand.dist.samp.pconst].
      
-
      View all issues with NAD status.
      
+
      683. regex_token_iterator summary error
      
+
      Section: 28.12.2 [re.tokiter] Status: NAD Editorial
+ Submitter: Eric Niebler Opened: 2007-06-02  Last modified: 2009-03-09
      
+
      View all other issues in [re.tokiter].
      
+
      View all issues with NAD Editorial status.
      
 
      Discussion:
      
-
        
-
      1. 
-The discussion in point T11 above regarding probabilities() similarly applies 
-to the method densities() of piecewise_constant_distribution.
-
        2. 
-
      2. 
 
        
-The design of the constructor
+28.12.2 [re.tokiter], p3 says:
 
        
-
        template <class InputIteratorB, class InputIteratorW> 
-piecewise_constant_distribution( InputIteratorB firstB, InputIteratorB lastB, 
-                                 InputIteratorW firstW);
-
        
+
        
 
        
-is unnecessarily unsafe, as there is no separate end-iterator given for the weights. I can't see 
-any performance or convenience reasons that would justify the risks inherent in such a function 
-interface, in particular the risk that input error might go unnoticed.
+After it is constructed, the iterator finds and stores a value
+match_results<BidirectionalIterator> position and sets the
+internal count N to zero.
 
        
-
        3. 
-
      
+
      
 
 
      
-Possible resolution: I propose to add an InputIteratorW lastW argument to the interface.
+Should read:
 
      
 
-
      [
-Stephan Tolksdorf adds pre-Bellevue:
-]
      
-
 
      
-In reply to the discussion in
-N2424
-I'd like to make the same comments as for 736.
+
      
+After it is constructed, the iterator finds and stores a value
+match_resultsregex_iterator<BidirectionalIterator, charT, traits>
+position and sets the internal count N to zero.
+
      
 
      
 
 
      [
-Bellevue:
+John adds:
 ]
      
 
 
-
      
-In N2424. There is already precedent elsewhere in the library. Follows existing convention. NAD.
-
      
+
      
+Yep, looks like a typo/administrative fix to me.
+
      
+
 
 
 
      Proposed resolution:
      
 
      
-See N2424
-for the proposed resolution.
 
      
 
-
      [
-Stephan Tolksdorf adds pre-Bellevue:
-]
      
 
 
-
      
-
      
-In 26.5.8.5.2 [rand.dist.samp.pconst]:
-
      
 
-
      
-Proposed wording a)
-
      
 
-
      
+
      
+
      684. Unclear which members of match_results should be used in comparison
      
+
      Section: 28.10 [re.results] Status: NAD Editorial
+ Submitter: Nozomu Katoo Opened: 2007-05-27  Last modified: 2008-03-12
      
+
      View all other issues in [re.results].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
 
      
-Change in para. 2
+In 28.4 [re.syn] of N2284, two template functions 
+are declared here: 
 
      
-
      
-Constructs a piecewise_constant_distribution object with n = 1, p0 = w0 = 1,
-b0 = 0, and b1 = 1
-
      
+
      // 28.10, class template match_results: 
+  <snip>
+// match_results comparisons 
+  template <class BidirectionalIterator, class Allocator> 
+    bool operator== (const match_results<BidirectionalIterator, Allocator>& m1, 
+                     const match_results<BidirectionalIterator, Allocator>& m2); 
+  template <class BidirectionalIterator, class Allocator> 
+    bool operator!= (const match_results<BidirectionalIterator, Allocator>& m1, 
+                     const match_results<BidirectionalIterator, Allocator>& m2); 
+
+// 28.10.6, match_results swap:
+
      
 
 
      
-and change in para. 5
+But the details of these two bool operator functions (i.e., which members of
+match_results should be used in comparison) are not described in any
+following sections.
 
      
 
-
      
-A vector<result_type> whose size member returns n and whose operator[]
-member returns pk
-the weight wk as a double value
-when invoked with argument k for k = 0, ..., n-1
-
      
+
      [
+John adds:
+]
      
 
-
      
 
+
      
+That looks like a bug: operator== should return true only if
+the two objects refer to the same match - ie if one object was constructed as a
+copy of the other.
+
      
+
+
      [
+Kona (2007): Bill and Pete to add minor wording to that proposed in
+N2409.
+]
      
+
+
+
+
      Proposed resolution:
      
 
      
-Proposed wording b)
+Add a new section after 28.10.6 [re.results.swap], which reads:
 
      
-
-
      
 
      
-Change both occurrences of
+28.10.7 match_results non-member functions.
 
      
 
 
      
-"piecewise_constant_distribution(InputIteratorB firstB, InputIteratorB lastB,
-                                 InputIteratorW firstW, InputIteratorW lastW)
+
      template<class BidirectionalIterator, class Allocator> 
+  bool operator==(const match_results<BidirectionalIterator, Allocator>& m1, 
+                  const match_results<BidirectionalIterator, Allocator>& m2);
+
      
+
      
+
      
+Returns: true only if the two objects refer to the same match.
+
      
+
      
 
      
 
+
      
+
      template<class BidirectionalIterator, class Allocator> 
+  bool operator!=(const match_results<BidirectionalIterator, Allocator>& m1, 
+                  const match_results<BidirectionalIterator, Allocator>& m2);
+
      
+
      
 
      
-and change in para. 3
+Returns: !(m1 == m2).
 
      
+
      
+
      
 
 
      
-the length of the sequence w starting from firstW shall be at least n,
-*firstW shall return a value w0 that is convertible to double, and any
-wk for k >= n shall be ignored by the distribution
-[firstW, lastW) shall form a sequence w of length n whose leading element
-w0 shall be convertible to double
+
      template<class BidirectionalIterator, class Allocator> 
+  void swap(match_results<BidirectionalIterator, Allocator>& m1, 
+            match_results<BidirectionalIterator, Allocator>& m2);
+
      
+
      
+
      
+Returns: m1.swap(m2).
+
      
 
      
-
 
      
 
 
-
      
-
+
      [
+Bellevue:  Proposed wording now in WP.
+]
      
 
 
 
 
 
 
      
-
      738. Editorial issue in [rand.adapt.disc]/3
      
-
      Section: 26.5.4.1 [rand.adapt.disc] Status: NAD Editorial
- Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-09-22
      
-
      View all issues with NAD Editorial status.
      
+
      686. Unique_ptr and shared_ptr fail to specify non-convertibility to int for unspecified-bool-type
      
+
      Section: 20.8.9.2.4 [unique.ptr.single.observers], 20.8.10.2.5 [util.smartptr.shared.obs] Status: NAD
+ Submitter: Beman Dawes Opened: 2007-06-14  Last modified: 2008-02-27
      
+
      View all issues with NAD status.
      
 
      Discussion:
      
 
      
-Since the template parameter p and r are of type size_t, the member n in the class 
-exposition should have type size_t, too.
+The standard library uses the operator unspecified-bool-type() const idiom in
+five places. In three of those places (20.7.16.2.3 [func.wrap.func.cap], function capacity 
+for example) the returned value is constrained to disallow
+unintended conversions to int. The standardese is
 
      
-
-
-
      Proposed resolution:
      
+
      
+The return type shall not be convertible to int.
+
      
 
      
-See N2424
-for the proposed resolution.
+This constraint is omitted for unique_ptr and shared_ptr. It should be added for those.
 
      
 
-
-
-
-
-
      
-
      739. Defect in [rand.util.canonical]/3
      
-
      Section: 26.5.7.2 [rand.util.canonical] Status: NAD
- Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
      
-
      View all other issues in [rand.util.canonical].
      
-
      View all issues with NAD status.
      
-
      Discussion:
      
-
      
-The complexity of generate_canonical is specified to be "exactly k=max(1, ceil(b/log2 
-R)) invocations of g". This terms involves a logarithm that is not rounded and hence can not (in 
-general) be computed at compile time. As this function template is performance critical, I propose 
-to replace ceil(b/log2 R) with ceil(b/floor(log2 R)).
-
      
-
-
      
-See N2424
-for further discussion.
-
      
-
-
      [
-Bellevue:
-]
      
+
      [
+Bellevue:
+]
      
 
 
 
      
-In N2424. Close NAD as described there.
+Close as NAD. Accepting paper
+N2435
+makes it irrelevant.
 
      
 
 
 
 
      Proposed resolution:
      
 
      
-See N2424
-for the proposed resolution.
+To the Returns paragraph for operator unspecified-bool-type()
+const
+of 20.8.9.2.4 [unique.ptr.single.observers] paragraph 11 and
+20.8.10.2.5 [util.smartptr.shared.obs] paragraph 16, add the sentence:
 
      
+
      
+The return type shall not be convertible to int.
+
      
+
+
+
      [
+Kona (2007): Uncertain if nullptr will address this issue.
+]
      
 
 
 
 
 
 
      
-
      741. Const-incorrect get_deleter function for shared_ptr
      
-
      Section: 20.8.13.2.11 [util.smartptr.getdeleter] Status: NAD
- Submitter: Daniel Krügler Opened: 2007-09-27  Last modified: 2008-02-27
      
-
      View all other issues in [util.smartptr.getdeleter].
      
-
      View all issues with NAD status.
      
+
      690. abs(long long) should return long long
      
+
      Section: 26.8 [c.math] Status: NAD Editorial
+ Submitter: Niels Dekker Opened: 2007-06-10  Last modified: 2007-07-25
      
+
      View all other issues in [c.math].
      
+
      View all issues with NAD Editorial status.
      
 
      Discussion:
      
 
      
-The following issue was raised by Alf P. Steinbach in c.l.c++.mod:
+Quoting the latest draft (n2135), 26.8 [c.math]: 
 
      
 
+
      
 
      
-According to the recent draft N2369, both the header memory synopsis
-of 20.8 [memory] and 20.8.13.2.11 [util.smartptr.getdeleter] declare:
+The added signatures are:
 
      
-
-
      template<class D, class T> D* get_deleter(shared_ptr<T> const& p);
+
      long abs(long); // labs()
+long abs(long long); // llabs()
 
      
+
      
+
      
+Shouldn't abs(long long) have long long as return type?
+
      
+
 
+
      Proposed resolution:
      
 
      
-This allows to retrieve the pointer to a mutable deleter of a const
-shared_ptr (if that owns one) and therefore contradicts the usual
-philosophy that associated functors are either read-only (e.g.
-key_comp or value_comp of std::map) or do at least reflect
-the mutability of the owner (as seen for the both overloads of
-unique_ptr::get_deleter).
-Even the next similar counter-part of get_deleter - the two
-overloads of function::target in the class template function
-synopsis 20.7.16.2 [func.wrap.func] or in 20.7.16.2.5 [func.wrap.func.targ] - do
-properly mirror the const-state of the owner.
+Change 26.8 [c.math]: 
 
      
+
      long long abs(long long); // llabs()
+
      
 
-Possible proposed resolutions:
 
+
      Rationale:
      
+Had already been fixed in the WP by the time the LWG reviewed this.
+
+
+
+
+
+
      
+
      697. New <system_error> header leads to name clashes
      
+
      Section: 19.5 [syserr] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2007-06-24  Last modified: 2008-01-06
      
+
      View all other issues in [syserr].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
 
      
-Replace the declarations of get_deleter in the header <memory>
-synopsis of 20.8 [memory] and in 20.8.13.2.11 [util.smartptr.getdeleter] by one of the
-following alternatives (A) or (B):
+The most recent state of 
+N2241
+as well as the current draft
+N2284
+(section 19.5 [syserr], p.2) proposes a
+new
+enumeration type posix_errno immediatly in the namespace std. One of
+the enumerators has the name invalid_argument, or fully qualified:
+std::invalid_argument. This name clashes with the exception type
+std::invalid_argument, see 19.2 [std.exceptions]/p.3. This clash makes
+e.g. the following snippet invalid:
 
      
 
-
        
-
      1. 
-Provide only the immutable variant. This would reflect the
-current praxis of container::get_allocator(), map::key_comp(), or
-map::value_comp.
+
        #include <system_error>
+#include <stdexcept>
 
-
        template<class D, class T> const D* get_deleter(shared_ptr<T> const& p);
+void foo() { throw std::invalid_argument("Don't call us - we call you!"); }
 
        
-
        2. 
-
      2. 
-Just remove the function.
-
        3. 
-
      
 
 
      
-Alberto Ganesh Barbati adds:
+I propose that this enumeration type (and probably the remaining parts
+of
+<system_error> as well) should be moved into one additional inner
+namespace, e.g. sys or system to reduce foreseeable future clashes
+due
+to the great number of members that std::posix_errno already contains
+(Btw.: Why has the already proposed std::sys sub-namespace from
+N2066
+been rejected?). A further clash candidate seems to be
+std::protocol_error
+(a reasonable name for an exception related to a std network library,
+I guess).
 
      
 
-
        
-
      1. 
 
        
-Replace it with two functions:
+Another possible resolution would rely on the proposed strongly typed
+enums,
+as described in N2213.
+But maybe the forbidden implicit conversion to integral types would
+make
+these enumerators less attractive in this special case?
 
        
-
        template <class D, class T> D get_deleter(shared_ptr<T> const&);
-template <class D, class T> bool has_deleter(shared_ptr<T> const&);
-
        
 
+
+
        Proposed resolution:
        
 
        
-The first one would throw if D is the wrong type, while the latter would
-never throw. This approach would reflect the current praxis of
-use_facet/has_facet, with the twist of returning the deleter by value as
-container::get_allocator() do.
+Fixed by issue 7 of N2422.
 
        
-
        2. 
-
      
 
+
+
+
+
+
+
      
+
      701. assoc laguerre poly's
      
+
      Section: TR1 5.2.1.1 [tr.num.sf.Lnm] Status: NAD
+ Submitter: Christopher Crawford Opened: 2007-06-30  Last modified: 2009-07-13
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
 
      
-Peter Dimov adds:
+I see that the definition the associated Laguerre
+polynomials TR1 5.2.1.1 [tr.num.sf.Lnm] has been corrected since
+N1687.
+However, the draft standard only specifies ranks of integer value m,
+while the associated Laguerre polynomials are actually valid for real
+values of m > -1.  In the case of non-integer values of m, the
+definition  Ln(m) = (1/n!)exx-m (d/dx)n (e-xxm+n)
+must be used, which also holds for integer values of m.  See
+Abramowitz & Stegun, 22.11.6 for the general case, and 22.5.16-17 for
+the integer case.  In fact fractional values are most commonly used in
+physics, for example to m = +/- 1/2 to describe the harmonic
+oscillator in 1 dimension, and 1/2, 3/2, 5/2, ... in 3
+dimensions.
 
      
-
-
      
 
      
-My favorite option is "not a defect". A, B and C break useful code.
+If I am correct, the calculation of the more general case is no
+more difficult, and is in fact the function implemented in the GNU
+Scientific Library.  I would urge you to consider upgrading the 
+standard, either adding extra functions for real m or switching the
+current ones to double.
 
      
-
      
 
 
      [
-Bellevue:
+Batavia (2009-05):
 ]
      
 
-
 
      
-Concern this is similar to confusing "pointer to const" with "a constant pointer".
+
      
+We understand the issue, and have opted not to extend as recommended.
+
      
+
      
+Move to NAD.
+
      
 
      
 
 
@@ -13861,71 +15309,66 @@ Concern this is similar to confusing "pointer to const" with "a constant pointer
 
 
 
      
-
      742. Enabling swap for proxy iterators
      
-
      Section: X [utility.arg.requirements] Status: NAD Editorial
- Submitter: Howard Hinnant Opened: 2007-10-10  Last modified: 2008-09-26
      
-
      View all other issues in [utility.arg.requirements].
      
-
      View all issues with NAD Editorial status.
      
+
      702. Restriction in associated Legendre functions
      
+
      Section: TR1 5.2.1.2 [tr.num.sf.Plm] Status: NAD
+ Submitter: Christopher Crawford Opened: 2007-06-30  Last modified: 2009-07-13
      
+
      View all issues with NAD status.
      
 
      Discussion:
      
 
      
-This issue was split from 672. 672 now just
-deals with changing the requirements of T in the Swappable
-requirement from CopyConstructible and CopyAssignable to
-MoveConstructible and MoveAssignable.
-
      
+One other small thing, in TR1 5.2.1.2 [tr.num.sf.Plm], the restriction should  be
+|x| <= 1, not x >= 0.
      
+
+
      [
+Batavia (2009-05):
+]
      
 
+
      
+
      
+The error has been corrected in the pending IS.
+
      
 
      
-This issue seeks to widen the Swappable requirement to support proxy iterators.  Here
-is example code:
+Move to NAD.
 
      
+
      
 
-
      namespace Mine {
 
-template <class T>
-struct proxy {...};
+
      Proposed resolution:
      
+
      
+
      
 
-template <class T>
-struct proxied_iterator
-{
-   typedef T value_type;
-   typedef proxy<T> reference;
-   reference operator*() const;
-   ...
-};
 
-struct A
-{
-   // heavy type, has an optimized swap, maybe isn't even copyable or movable, just swappable
-   void swap(A&);
-   ...
-};
 
-void swap(A&, A&);
-void swap(proxy<A>, A&);
-void swap(A&, proxy<A>);
-void swap(proxy<A>, proxy<A>);
 
-}  // Mine
 
-...
+
      
+
      707. null pointer constant for exception_ptr
      
+
      Section: 18.8.5 [propagation] Status: NAD
+ Submitter: Jens Maurer Opened: 2007-07-20  Last modified: 2008-02-25
      
+
      View other active issues in [propagation].
      
+
      View all other issues in [propagation].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
 
-Mine::proxied_iterator<Mine::A> i(...)
-Mine::A a;
-swap(*i1, a);
-
      
+
      
+From the Toronto Core wiki:
+
      
 
 
      
-The key point to note in the above code is that in the call to swap, *i1
-and a are different types (currently types can only be Swappable with the
-same type).  A secondary point is that to support proxies, one must be able to pass rvalues
-to swap.  But note that I am not stating that the general purpose std::swap
-should accept rvalues!  Only that overloaded swaps, as in the example above, be allowed
-to take rvalues.
+What do you mean by "null pointer constant"? How do you guarantee that
+exception_ptr() == 1 doesn't work?  Do you even want to prevent that?
+What's the semantics?  What about void *p = 0; exception_ptr() == p?
+Maybe disallow those in the interface, but how do you do that with
+portable C++? Could specify just "make it work".
+
      
+
+
      
+Peter's response:
 
      
 
 
      
-That is, no standard library code needs to change.  We simply need to have a more flexible
-definition of Swappable.
+null pointer constant as defined in 4.10 [conv.ptr]. Intent is "just make it
+work", can be implemented as assignment operator taking a unique pointer
+to member, as in the unspecified bool type idiom.
 
      
 
 
      [
@@ -13935,27 +15378,15 @@ Bellevue:
 
 
      
 
      
-While we believe Concepts work will define a swappable concept, we
-should still resolve this issue if possible to give guidance to the
-Concepts work.
-
      
-
      
-Would an ambiguous swap function in two namespaces found by ADL break
-this wording? Suggest that the phrase "valid expression" means such a
-pair of types would still not be swappable.
+Original implementation was possible using the "unspecified-null-pointer" idiom, similar to unspecified-bool.
 
      
 
      
-Motivation is proxy-iterators, but facility is considerably more
-general. Are we happy going so far?
+Even simpler now with nullptr_t.
 
      
 
      
-We think this wording is probably correct and probably an improvement on
-what's there in the WP. On the other hand, what's already there in the
-WP is awfully complicated. Why do we need the two bullet points? They're
-too implementation-centric. They don't add anything to the semantics of
-what swap() means, which is there in the post-condition. What's wrong
-with saying that types are swappable if you can call swap() and it
-satisfies the semantics of swapping?
+NAD Rationale : null pointer constant is a perfectly defined term, and
+while API is clearly implementable there is no need to spell out
+implementation details.
 
      
 
      
 
@@ -13963,109 +15394,76 @@ satisfies the semantics of swapping?
 
 
      Proposed resolution:
      
 
      
-Change X [utility.arg.requirements]:
 
      
 
-
      
 
+
+
+
+
      
+
      708. Locales need to be per thread and updated for POSIX changes
      
+
      Section: 22 [localization] Status: NAD Future
+ Submitter: Peter Dimov Opened: 2007-07-28  Last modified: 2009-07-16
      
+
      View all other issues in [localization].
      
+
      View all issues with NAD Future status.
      
+
      Discussion:
      
 
      
--1- The template definitions in the C++ Standard Library refer to various
-named requirements whose details are set out in tables 31-38. In these
-tables, T and V are is a types to be supplied by a C++ program
-instantiating a template; a, b, and c are
-values of type const T; s and t are modifiable
-lvalues of type T; u is a value of type (possibly
-const) T; and rv is a non-const
-rvalue of type T; w is a value of type T; and v is a value of type V.
+The POSIX "Extended API Set Part 4,"
 
      
-
-
-
-
-
-
-
-
      Table 37: Swappable requirements [swappable]
      expressionreturn typepost-condition
      swap(sw,tv)voidtw has the value originally
-held by uv, and
-uv has the value originally held
-by tw
      
+
      
+http://www.opengroup.org/sib/details.tpl?id=C065
+
      
 
      
-The Swappable requirement is met by satisfying one or more of the following conditions:
+introduces extensions to the C locale mechanism that
+allow multiple concurrent locales to be used in the same application
+by introducing a type locale_t that is very similar to
+std::locale, and a number of _l functions that make use of it.
+
      
+
      
+The global locale (set by setlocale) is now specified to be per-
+process. If a thread does not call uselocale, the global locale is
+in effect for that thread. It can install a per-thread locale by
+using uselocale.
+
      
+
      
+There is also a nice querylocale mechanism by which one can obtain
+the name (such as "de_DE") for a specific facet, even for combined
+locales, with no std::locale equivalent.
+
      
+
      
+std::locale should be harmonized with the new POSIX locale_t
+mechanism and provide equivalents for uselocale and querylocale.
 
      
-
        
-
      • 
-T is Swappable if T and V are
-the same type and  T satisfies the
-CopyConstructible
-MoveConstructible requirements (Table 34
-33) and the CopyAssignable
-MoveAssignable requirements (Table 36
-35);
-
        • 
-
      • 
-T is Swappable with V if a namespace scope function named
-swap exists in the same namespace as the definition of
-T or V, such that the expression
-swap(tw,u v) is valid and has the
-semantics described in this table.
-
        • 
-
      
-
      
-
      
 
+
      [
+Kona (2007): Bill and Nick to provide wording.
+]
      
 
 
-
      Rationale:
      
 
      [
-post San Francisco:
+San Francisco: Bill and Nick still intend to provide wording, but this
+is a part of the task to be addressed by the group that will look into
+issue 860.
 ]
      
 
 
-
      
-Solved by
-N2758.
-
      
-
-
-
-
-
-
-
      
-
      745. copy_exception API slices.
      
-
      Section: 18.8.5 [propagation] Status: NAD
- Submitter: Alisdair Meredith Opened: 2007-10-10  Last modified: 2008-02-25
      
-
      View other active issues in [propagation].
      
-
      View all other issues in [propagation].
      
-
      View all issues with NAD status.
      
-
      Discussion:
      
-
      
-It could be I did not understand the design rationale, but I thought
-copy_exception would produce an exception_ptr to the most-derived (dynamic)
-type of the passed exception.  Instead it slices, which appears to be less
-useful, and a likely source of FAQ questions in the future.
-
      
-
      
-(Peter Dimov suggests NAD)
-
      
-
 
      [
-Bellevue: 
+2009-07 Frankfurt:
 ]
      
 
 
 
      
 
      
-How could this be implemented in a way that the dynamic type is cloned?
+It's our intention to stay in sync with WG14. If WG14 makes a decision
+that requires a change in WG21 the issue will be reopened.
 
      
 
      
-The feature is designed to create an exception_ptr from an object whose
-static type is identical to the dynamic type and thus there is no
-slicing involved.
+Move to NAD Future.
 
      
 
      
 
 
+
 
      Proposed resolution:
      
 
      
 
      
@@ -14075,131 +15473,89 @@ slicing involved.
 
 
 
      
-
      748. The is_abstract type trait is defined by reference to 10.4.
      
-
      Section: 20.6.4.3 [meta.unary.prop] Status: NAD
- Submitter: Alisdair Meredith Opened: 2007-10-10  Last modified: 2009-05-01
      
-
      View other active issues in [meta.unary.prop].
      
-
      View all other issues in [meta.unary.prop].
      
-
      View all issues with NAD status.
      
+
      717. Incomplete valarray::operator[] specification in [valarray.access]
      
+
      Section: 26.6.2.3 [valarray.access] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2007-08-27  Last modified: 2008-09-22
      
+
      View all other issues in [valarray.access].
      
+
      View all issues with NAD Editorial status.
      
 
      Discussion:
      
 
      
-I am trying to decide is a pure virtual function is a necessary as well as
-sufficient requirement to be classified as abstract?
-
      
-
      
-For instance, is the following (non-polymorphic) type considered abstract?
-
      
-
      struct abstract {
-protected:
- abstract(){}
- abstract( abstract const & ) {}
- ~abstract() {}
-};
-
      
-
      
-(Suggested that this may be NAD, with an editorial fix-up from Pete on the
-core wording to make clear that abstract requires a pure virtual function)
+Since the return type of valarray's operator[] const overload has been
+changed to const T& as described in 389 several paragraphs of
+the section 26.6.2.3 [valarray.access] are now
+incompletely
+specified, because many requirements and guarantees should now also
+apply to the const overload. Most notably, the address and reference
+guarantees should be extended to the const overload case.
 
      
 
 
 
      Proposed resolution:
      
 
      
-Core has clarified that the definition abstract is adequate. Issue withdrawn by submitter. NAD.
-
      
-
-
-
-
-
-
      
-
      754. Ambiguous return clause for std::uninitialized_copy
      
-
      Section: 20.8.11.2 [uninitialized.copy] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2007-10-15  Last modified: 2008-07-02
      
-
      View all other issues in [uninitialized.copy].
      
-
      View all issues with NAD Editorial status.
      
-
      Discussion:
      
-
      
-14882-2003, [lib.uninitialized.copy] is currently written as follows:
+Change 26.6.2.3 [valarray.access]:
 
      
 
 
      
-
      template <class InputIterator, class ForwardIterator>
-  ForwardIterator uninitialized_copy(InputIterator first, InputIterator last,
-                                     ForwardIterator result);
-
      
-
      
 
      
--1- Effects:
+-1- When applied to a constant array, the subscript operator returns a
+reference to the corresponding element of the array. When applied to a
+non-constant array, tThe subscript operator returns a
+reference to the corresponding element of the array.
 
      
-
      for (; first != last; ++result, ++first)
-  new (static_cast<void*>(&*result))
-    typename iterator_traits<ForwardIterator>::value_type(*first);
-
      
+
 
      
--2- Returns: result
+-3- The expression &a[i+j] == &a[i] + j evaluates as true for all size_t i
+and size_t j such that i+j is less 
+than the length of the non-constant array a.
 
      
-
      
-
      
 
 
      
-similarily for N2369, and its corresponding section
-20.8.11.2 [uninitialized.copy].
+-4- Likewise, the expression &a[i] != &b[j] evaluates
+as true for any two non-constant arrays a and
+b and for any size_t i and size_t j such that
+i is less than the length of a and j is less
+than the length of b. This property indicates an absence of
+aliasing and may be used to advantage by optimizing
+compilers.281)
 
      
 
 
      
-It's not clear to me what the return clause is supposed to mean, I see
-two
-possible interpretations:
+-5- The reference returned by the subscript operator for an non-constant array is guaranteed to be valid until
+the member function resize(size_t, T) (26.5.2.7) is called for that array or until the lifetime 
+of that array ends, whichever happens first.
 
      
 
-
        
-
      1. 
-The notion of result is supposed to mean the value given by the
-function parameter result [Note to the issue editor: Please use italics for
-result].
-This seems somewhat implied by recognizing that both the function
-parameter
-and the name used in the clause do have the same italic font.
-
        2. 
-
      2. 
-The notion of "result" is supposed to mean the value of result
-after the
-preceding effects clause. This is in fact what all implementations I
-checked
-do (and which is probably it's intend, because it matches the
-specification of std::copy).
-
        3. 
-
      
+
      
 
-
      
-The problem is: I see nothing in the standard which grants that this
-interpretation
-is correct, specifically [lib.structure.specifications] or
-17.5.1.4 [structure.specifications]
-resp. do not clarify which "look-up" rules apply for names found in
-the elements
-of the detailed specifications - Do they relate to the corresponding
-synopsis or
-to the effects clause (or possibly other elements)? Fortunately most
-detailed
-descriptions are unambigious in this regard, e.g. this problem does
-not apply
-for std::copy.
-
      
 
 
 
-
      Proposed resolution:
      
+
+
+
      
+
      718. basic_string is not a sequence
      
+
      Section: 21.4 [basic.string] Status: NAD Editorial
+ Submitter: Bo Persson Opened: 2007-08-18  Last modified: 2009-07-16
      
+
      View all other issues in [basic.string].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
 
      
-Change the wording of the return clause to say (20.8.11.2 [uninitialized.copy]):
+Paragraph 21.4 [basic.string]/3 states:
 
      
 
 
      
 
      
--2- Returns: The value of result after effects have taken place.
+The class template basic_string conforms to the requirements for a 
+Sequence (23.1.1) and for a Reversible Container (23.1).
 
      
 
      
 
+
      
+First of all, 23.2.3 [sequence.reqmts] is no longer "Sequence" but "Sequence container". 
+Secondly, after the resent changes to containers (emplace, push_back, 
+const_iterator parameters to insert and erase), basic_string is not 
+even close to conform to the current requirements.
+
      
 
 
      [
 Bellevue:
@@ -14207,104 +15563,107 @@ Bellevue:
 
 
 
      
-Resolution: NAD editorial -- project editor to decide if change is
-worthwhile. Concern is that there are many other places this might
-occur.
+
        
+
      • emplace, for example, may not make sense for strings. Is also likely suboptimal
        • 
+
      • with concepts do we need to maintain string as sequence container?
        • 
+
      • One approach might be to say something like: string is a sequence except it doesn't have these functions
        • 
+
      
+
        
+
      • basic_string already has push_back
        • 
+
      • const_iterator parameters to insert and erase should be added to basic_string
        • 
+
      • this leaves emplace to handle -- we have the following options:
+
          
+
        • option 1: add it to string even though it's optional
          • 
+
        • option 2: make emplace optional to sequences (move from table 89 to 90)
          • 
+
        • option 3: say string not sequence (the proposal),
          • 
+
        • option 4: add an exception to basic string wording.
          • 
+
        
+
        • 
+
      
+General consensus is to suggest option 2.
 
      
 
+
      [
+2009-07 Frankfurt:
+]
      
 
 
+
      
+Move to NAD Editorial
+
      
 
-
      
-
      756. Container adaptors push
      
-
      Section: 23.3.5 [container.adaptors] Status: NAD Editorial
- Submitter: Paolo Carlini Opened: 2007-10-31  Last modified: 2008-06-18
      
-
      View all issues with NAD Editorial status.
      
-
      Discussion:
      
+
+
+
      Proposed resolution:
      
 
      
-After n2369 we have a single push_back overload in the sequence containers,
-of the "emplace" type. At variance with that, still in n2461, we have
-two separate overloads, the C++03 one + one taking an rvalue reference
-in the container adaptors. Therefore, simply from a consistency point of
-view, I was wondering whether the container adaptors should be aligned
-with the specifications of the sequence container themselves: thus have
-a single push along the lines:
+Remove this sentence, in recognition of the fact that basic_string is 
+not just a vector-light for literal types, but something quite 
+different, a string abstraction in its own right.
 
      
 
-
      template<typename... _Args>
-void
-push(_Args&&... __args)
-  { c.push_back(std::forward<_Args>(__args)...); }
-
      
 
-
      [
-Related to 767
-]
      
 
 
 
-
      Proposed resolution:
      
+
      
+
      721. wstring_convert inconsistensies
      
+
      Section: 22.3.3.2.2 [conversions.string] Status: NAD
+ Submitter: Bo Persson Opened: 2007-08-27  Last modified: 2009-07-16
      
+
      View all other issues in [conversions.string].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
 
      
-Change 23.3.5.1.1 [queue.defn]:
+Paragraph 3 says that the Codecvt template parameter shall meet the 
+requirements of std::codecvt, even though std::codecvt itself cannot 
+be used (because of a protected destructor).
 
      
 
-
      void push(const value_type& x) { c.push_back(x); }
-void push(value_type&& x) { c.push_back(std::move(x)); }
-template<class... Args> void push(Args&&... args) { c.push_back(std::forward<Args>(args)...); }
-
      
-
 
      
-Change 23.3.5.2 [priority.queue]:
+How are we going to explain this code to beginning programmers?
 
      
 
-
      void push(const value_type& x) { c.push_back(x); }
-void push(value_type&& x) { c.push_back(std::move(x)); }
-template<class... Args> void push(Args&&... args) { c.push_back(std::forward<Args>(args)...); }
+
      template<class I, class E, class S>
+struct codecvt : std::codecvt<I, E, S>
+{
+    ~codecvt()
+    { }
+};
+
+void main()
+{
+    std::wstring_convert<codecvt<wchar_t, char, std::mbstate_t> > compiles_ok;
+    
+    std::wstring_convert<std::codecvt<wchar_t, char, std::mbstate_t> >   not_ok;
+}
 
      
 
-
      
-Change 23.3.5.2.2 [priqueue.members]:
-
      
+
      [
+San Francisco:
+]
      
+
 
 
      
-
      void push(const value_type& x);
-
      
-
      
-
      
-Effects:
-
      
-
      c.push_back(x);
-push_heap(c.begin(), c.end(), comp);
-
      
+Bill will propose a resolution.
 
      
 
-
      template<class... Args> void push(value_type Args&&... x args);
-
      
+
      [
+2009-07 Frankfurt:
+]
      
+
+
 
      
 
      
-Effects:
+codecvt isn't intended for beginning programmers. This is a regrettable
+consequence of the original design of the facet.
+
      
+
      
+Move to NAD.
 
      
-
      c.push_back(std::moveforward<Args>(x args)...);
-push_heap(c.begin(), c.end(), comp);
-
      
-
      
 
      
 
+
+
      Proposed resolution:
      
 
      
-Change 23.3.5.3.1 [stack.defn]:
-
      
-
-
      void push(const value_type& x) { c.push_back(x); }
-void push(value_type&& x) { c.push_back(std::move(x)); }
-template<class... Args> void push(Args&&... args) { c.push_back(std::forward<Args>(args)...); }
-
      
-
-
-
-
      Rationale:
      
-
      
-Addressed by
-N2680 Proposed Wording for Placement Insert (Revision 1).
 
      
 
 
@@ -14312,145 +15671,178 @@ Addressed by
 
 
 
      
-
      757. Typo in the synopsis of vector
      
-
      Section: 23.3.6 [vector] Status: NAD Editorial
- Submitter: Paolo Carlini Opened: 2007-11-04  Last modified: 2008-07-02
      
-
      View all other issues in [vector].
      
+
      725. Optional sequence container requirements column label
      
+
      Section: 23.2.3 [sequence.reqmts] Status: NAD Editorial
+ Submitter: David Abrahams Opened: 2007-09-16  Last modified: 2008-09-22
      
+
      View all other issues in [sequence.reqmts].
      
 
      View all issues with NAD Editorial status.
      
 
      Discussion:
      
 
      
-In the synopsis 23.3.6 [vector], there is the signature:
-
      
-
-
      void insert(const_iterator position, size_type n, T&& x);
-
      
-
-
      
-instead of:
+Table 90: (Optional sequence container operations) states the
+"assertion note pre/post-condition" of operator[] to be
 
      
 
-
      iterator insert(const_iterator position, T&& x);
+
      *(a.begin() + n)
 
      
 
 
      
-23.3.6.4 [vector.modifiers] is fine.
+Surely that's meant to be "operational semantics?"
 
      
 
 
 
 
      Proposed resolution:
      
-
      
-Change the synopsis in 23.3.6 [vector]:
-
      
+
      
+
+
+
+
+
+
      Table 90: Optional sequence container operations
      expression return type assertion/note
      pre/post-condition
       operational semantics      		 container
      
+
      
 
-
      iterator insert(const_iterator position, const T& x); 
-iterator insert(const_iterator position, T&& x);
-void     insert(const_iterator position, size_type n, const T& x); 
-void     insert(const_iterator position, size_type n, T&& x);
-
      
 
 
 
 
 
 
      
-
      763. Renaming emplace() overloads
      
-
      Section: 23.2.4 [associative.reqmts] Status: NAD
- Submitter: Sylvain Pion Opened: 2007-12-04  Last modified: 2008-03-12
      
-
      View other active issues in [associative.reqmts].
      
-
      View all other issues in [associative.reqmts].
      
+
      729. Problem in [rand.req.eng]/3
      
+
      Section: X [rand.req.eng] Status: NAD
+ Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
      
+
      View all other issues in [rand.req.eng].
      
 
      View all issues with NAD status.
      
 
      Discussion:
      
 
      
-The associative containers provide 2 overloads of emplace():
+The 3rd table row in X [rand.req.eng]/3 requires random number engines to accept any 
+arithmetic type as a seed, which is then casted to the engine's result_type and subsequently 
+used for seeding the state of the engine. The requirement stated as "Creates an engine with 
+initial state determined by static_cast<X::result_type>(s)" forces random number engines 
+to either use a seeding method that completely depends on the result_type (see the discussion 
+of seeding for the mersenne_twister_engine in point T2 above) or at least to throw away "bits 
+of randomness" in the seed value if the result_type is smaller than the seed type. This seems 
+to be inappropriate for many modern random number generators, in particular F2-linear or 
+cryptographic ones, which operate on an internal bit array that in principle is independent of the 
+type of numbers returned.
 
      
 
-
      template <class... Args> pair<iterator, bool> emplace(Args&&... args);
-template <class... Args> iterator emplace(const_iterator position, Args&&... args);
-
      
+
      
+Posible resolution: I propose to change the wording to a version similar to "Creates an 
+engine with initial state determined by static_cast<UintType>(s), where UintType is an 
+implementation specific unsigned integer type."
+
      
 
 
      
-This is a problem if you mean the first overload while passing
-a const_iterator as first argument.
+Additionally, the definition of s in X [rand.req.eng]/1 c) could be restricted to unsigned integer types.
+
      
+
+
      
+Similarly, the type of the seed in X [rand.req.adapt]/3 e) could be left unspecified.
+
      
+
+
      
+See N2424
+for further discussion.
 
      
 
 
      [
-Related to 767
+Stephan Tolksdorf adds pre-Bellevue:
 ]
      
 
 
+
      
+
      
+In reply to the discussion in
+N2424
+regarding this issue:
+
      
+
      
+The descriptions of all engines and engine adaptors given in sections
+26.5.3 [rand.eng] and 26.5.4 [rand.adapt] already specify the concrete
+types of the integer arguments for seeding. Hence, relaxing the general
+requirement in X [rand.req.eng] would not affect portability and
+reproducibility of the standard library. Furthermore, it is not clear to
+me what exactly the guarantee "with initial state determined by
+static_cast<X::result_type>(s)" is useful for. On the other hand,
+relaxing the requirement would allow developers to implement  other
+random number engines that do not have to cast all arithmetic seed
+arguments to their result_types.
+
      
+
      
+
 
      [
 Bellevue:
 ]
      
 
 
 
      
+Propose close NAD for the reasons given in N2424.
 
      
+
+
+
+
+
      Proposed resolution:
      
 
      
-This can be disambiguated by passing "begin" as the first argument in
-the case when the non-default choice is desired. We believe that desire
-will be rare.
+See N2424
+for further discussion.
 
      
+
+
      [
+Stephan Tolksdorf adds pre-Bellevue:
+]
      
+
+
+
      
 
      
-Resolution: Change state to NAD.
+Change row 3 of table 105 "Random number engine requirements" in X [rand.req.eng]/3
 
      
 
+
      
+Creates an engine with initial state determined by
+static_cast<X::result_type>(s)
+
      
 
-
      Proposed resolution:
      
 
      
-Rename one of the two overloads.
-For example to emplace_here, hint_emplace...
+Similarly, change X [rand.req.adapt]/3 e)
 
      
 
+
      
+When X::X is invoked with an X::result_type value s
+of arithmetic type (3.9.1), ...
+
      
+
+
      
+
+
 
 
 
 
 
      
-
      764. equal_range on unordered containers should return a pair of local_iterators
      
-
      Section: 23.2.5 [unord.req] Status: NAD
- Submitter: Joe Gottman Opened: 2007-11-29  Last modified: 2008-03-12
      
-
      View other active issues in [unord.req].
      
-
      View all other issues in [unord.req].
      
+
      730. Comment on [rand.req.adapt]/3 e)
      
+
      Section: X [rand.req.adapt] Status: NAD
+ Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
      
 
      View all issues with NAD status.
      
 
      Discussion:
      
 
      
-    A major attribute of the unordered containers is that iterating 
-though them inside a bucket is very fast while iterating between buckets 
-can be much slower.  If an unordered container has a low load factor, 
-iterating between the last iterator in one bucket and the next iterator, 
-which is in another bucket, is O(bucket_count()) which may be much 
-larger than O(size()).
-
      
-
      
-    If b is an non-const unordered container of type B and k is an 
-object of it's key_type, then b.equal_range(k) currently returns 
-pair<B::iterator, B::iterator>. Consider the following code:
+If an engine adaptor is invoked with an argument of type seed_seq, then all base 
+engines are specified to be seeded with this seed_seq. As seed_seq's randomization method is 
+qualified as constant, this procedure will ef fectively initialize all base engines with the same seed 
+(though the resulting state might still dif fer to a certain degree if the engines are of different types). 
+It is not clear whether this mode of operation is in general appropriate, hence -- as far as the 
+stated requirements are of general nature and not just specific to the engine adaptors provided by 
+the library -- it might be better to leave the behaviour unspecified, since the current definition of 
+seed_seq does not allow for a generally satisfying specification.
 
      
 
-
      B::iterator lb, ub;
-tie(lb, ub) = b.equal_range(k);
-for (B::iterator it = lb; it != ub; ++it) {
-        // Do something with *it
-}
-
      
-
 
      
-If b.equal_range(k) returns a non-empty range (i.e. b contains at least 
-on element whose key is equivalent to k), then every iterator in the 
-half-open range [lb, ub) will be in the same bucket, but ub will likely 
-either be in a different bucket or be equal to b.end().  In either case, 
-iterating between ub - 1 and ub could take a much longer time than 
-iterating through the rest of the range.
+Posssible resolution: [As above]
 
      
+
 
      
-If instead of returning pair<iterator, iterator>, equal_range were to 
-return pair<local_iterator, local_iterator>, then ub (which, like lb, 
-would now be a local_iterator) could be guaranteed to always be in the 
-same bucket as lb. In the cases where currently ub is equal to b.end()
-or is in a different bucket, ub would be equal to b.end(b.bucket(key)). 
-  This would make iterating between lb and ub much faster, as every 
-iteration would be constant time.
+See N2424
+for further discussion.
 
      
 
 
      [
@@ -14459,105 +15851,119 @@ Bellevue:
 
 
 
      
-The proposed resolution breaks consistency with other container types
-for dubious benefit, and iterators are already constant time.
+Close NAD for the reasons given in N2424.
 
      
 
 
 
 
      Proposed resolution:
      
 
      
-Change the entry for equal_range in Table 93 (23.2.5 [unord.req]) as follows:
+See N2424
+for the proposed resolution.
 
      
-
-
-
-
-
-
-
-
-
-
-
-
      expression return type assertion/note pre/post-condition complexity
      b.equal_range(k)pair<local_iterator,local_iterator>; pair<const_local_iterator,const_local_iterator> for const b.Returns a range containing all elements with keys equivalent to k. Returns make_pair(b.end(b.bucket(key)),b.end(b.bucket(key))) if no such elements exist.Average case Θ(b.count(k)). Worst case Θ(b.size()). 
      
 
 
 
 
 
 
      
-
      767. Forwarding and backward compatibility
      
-
      Section: 23 [containers] Status: NAD Editorial
- Submitter: Sylvain Pion Opened: 2007-12-28  Last modified: 2008-06-18
      
-
      View other active issues in [containers].
      
-
      View all other issues in [containers].
      
-
      View all issues with NAD Editorial status.
      
+
      731. proposal for a customizable seed_seq
      
+
      Section: 26.5.7.1 [rand.util.seedseq] Status: NAD
+ Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
      
+
      View all other issues in [rand.util.seedseq].
      
+
      View all issues with NAD status.
      
 
      Discussion:
      
 
      
-Playing with g++'s C++0X mode, I noticed that the following
-code, which used to compile:
+The proper way to seed random number engines seems to be the most frequently 
+discussed issue of the 26.5 [rand] proposal. While the new seed_seq approach is already rather 
+general and probably sufficient for most situations, it is unlikely to be optimal in every case (one 
+problem was pointed out in point T5 above). In some situations it might, for instance, be better to 
+seed the state with a cryptographic generator. 
 
      
-
-
      #include <vector>
-
-int main()
-{
-    std::vector<char *> v;
-    v.push_back(0);
-}
-
      
-
 
      
-now fails with the following error message:
+In my opinion this is a pretty strong argument for extending the standard with a simple facility to 
+customize the seeding procedure. This could, for example, be done with the following minimal 
+changes:
 
      
 
-
      .../include/c++/4.3.0/ext/new_allocator.h: In member
-function 'void __gnu_cxx::new_allocator<_Tp>::construct(_Tp*,
-_Args&& ...) [with _Args = int, _Tp = char*]':
-.../include/c++/4.3.0/bits/stl_vector.h:707: instantiated from 'void
-std::vector<_Tp, _Alloc>::push_back(_Args&& ...) [with
-_Args = int, _Tp = char*, _Alloc = std::allocator<char*>]'
-test.cpp:6: instantiated from here
-.../include/c++/4.3.0/ext/new_allocator.h:114: error: invalid
-conversion from 'int' to 'char*'
-
      
-
 
      
-As far as I know, g++ follows the current draft here.
+Possible resolution:
 
      
-
      
-Does the committee really intend to break compatibility for such cases?
+
+
        
+
      1. 
+Turn the interface specification of 26.5.7.1 [rand.util.seedseq]/2 into a "SeedSeq" requirement, where the 
+exact behaviour of the constructors and the randomize method are left unspecified and where the
+const qualification for randomize is removed. Classes implementing this interface are additionally 
+required to specialize the traits class in c).
+
        2. 
+
      2. 
+Provide the class seed_seq as a default implementation of the SeedSeq interface.
+
        3. 
+
      3. 
+
        
+Supplement the seed_seq with a traits class
 
        
+
        template <typename T> 
+struct is_seed_seq { static const bool value = false; }
+
        
+
        and the specialization
        
+
        template <> 
+struct is_seed_seq<seed_seq> { static const bool value = true; }
+
        
+
        which users can supplement with further specializations.
        
+
        4. 
+
      4. 
+Change X [rand.req.eng]/1 d) to "q is an lvalue of a type that fulfils the SeedSeq requirements", and 
+modify the constructors and seed methods in 26.5.3 [rand.eng] appropriately (the actual implementation 
+could be done using the SFINAE technique).
+
        5. 
+
      
 
 
      [
-Sylvain adds: 
+Bellevue:
 ]
      
 
 
 
      
+See N2424. Close NAD but note that "conceptizing" the library may cause
+this problem to be solved by that route.
+
      
+
+
+
      Proposed resolution:
      
 
      
-I just noticed that std::pair has the same issue.
-The following now fails with GCC's -std=c++0x mode:
+See N2424
+for the proposed resolution.
 
      
 
-
      #include <utility>
 
-int main()
-{
-   std::pair<char *, char *> p (0,0);
-}
-
      
 
+
+
+
      
+
      732. Defect in [rand.dist.samp.genpdf]
      
+
      Section: X [rand.dist.samp.genpdf] Status: NAD Editorial
+ Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2009-03-09
      
+
      View all other issues in [rand.dist.samp.genpdf].
      
+
      View all issues with NAD Editorial status.
      
+
      Duplicate of: 795
      
+
      Discussion:
      
 
      
-I have not made any general audit for such problems elsewhere.
+X [rand.dist.samp.genpdf] describes the interface for a distribution template that is 
+meant to simulate random numbers from any general distribution given only the density and the 
+support of the distribution. I'm not aware of any general purpose algorithm that would be capable 
+of correctly and efficiently implementing the described functionality. From what I know, this is 
+essentially an unsolved research problem. Existing algorithms either require more knowledge 
+about the distribution and the problem domain or work only under very limited circumstances. 
+Even the state of the art special purpose library UNU.RAN does not solve the problem in full 
+generality, and in any case, testing and customer support for such a library feature would be a 
+nightmare.
 
      
-
      
-
-
      [
-Related to 756
-]
      
 
+
      
+Possible resolution: For these reasons, I propose to delete section X [rand.dist.samp.genpdf].
+
      
 
 
      [
 Bellevue:
@@ -14566,218 +15972,120 @@ Bellevue:
 
 
      
 
      
-Motivation is to handle the old-style int-zero-valued NULL pointers.
-Problem: this solution requires concepts in some cases, which some users
-will be slow to adopt. Some discussion of alternatives involving
-prohibiting variadic forms and additional library-implementation
-complexity.
+Disagreement persists.
 
      
 
      
-Discussion of "perfect world" solutions, the only such solution put
-forward being to retroactively prohibit use of the integer zero for a
-NULL pointer. This approach was deemed unacceptable given the large
-bodies of pre-existing code that do use integer zero for a NULL pointer.
+Objection to this issue is that this function takes a general functor.
+The general approach would be to normalize this function, integrate it,
+and take the inverse of the integral, which is not possible in general.
+An example function is sin(1+n*x) -- for any spatial frequency that the
+implementor chooses, there is a value of n that renders that choice
+arbitrarily erroneous.
 
      
 
      
-Another approach is to change the member names. Yet another approach is
-to forbid the extension in absence of concepts.
+Correction: The formula above should instead read 1+sin(n*x).
 
      
 
      
-Resolution: These issues (756, 767, 760, 763) will be subsumed into a
-paper to be produced by Alan Talbot in time for review at the 2008
-meeting in France. Once this paper is produced, these issues will be
-moved to NAD.
+Objector proposes the following possible compromise positions:
 
      
+
        
+
      • 
+rand.dist.samp.genpdf takes an number of points so that implementor need not guess.
+
        • 
+
      • replace rand.disk.samp.genpdf with an extension to either or both
+of the discrete functions to take arguments that take a functor and
+number of points in place of the list of probabilities. Reference
+issues 793 and 794.
+
        • 
+
      
 
      
 
 
 
 
      Proposed resolution:
      
 
      
-Add the following rows to Table 90 "Optional sequence container operations", 23.2.3 [sequence.reqmts]:
+See N2813
+for the proposed resolution.
 
      
 
-
      
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
 
-
-
-
-
-
-
+
      Rationale:
      
+Addressed by
+N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
 
-
-
-
-
-
-
 
-
      expression return type assertion/note
      pre-/post-condition      		 container
      
-a.push_front(t)
-
-void
-
-a.insert(a.begin(), t)
      
-Requires: T shall be CopyConstructible.
-      		
-list, deque
-
      
-a.push_front(rv)
-
-void
-
-a.insert(a.begin(), rv)
      
-Requires: T shall be MoveConstructible.
-      		
-list, deque
-
      
-a.push_back(t)
-
-void
-
-a.insert(a.end(), t)
      
-Requires: T shall be CopyConstructible.
-      		
-list, deque, vector, basic_string
-
      
-a.push_back(rv)
-
-void
-
-a.insert(a.end(), rv)
      
-Requires: T shall be MoveConstructible.
-      		
-list, deque, vector, basic_string
-
      
-
      
 
-
      
-Change the synopsis in 23.3.2 [deque]:
-
      
 
-
      void push_front(const T& x);
-void push_front(T&& x);
-void push_back(const T& x);
-void push_back(T&& x);
-template <class... Args> requires Constructible<T, Args&&...> void push_front(Args&&... args);
-template <class... Args> requires Constructible<T, Args&&...> void push_back(Args&&... args);
-
      
 
+
      
+
      733. Comment on [rand.req.dist]/9
      
+
      Section: X [rand.req.dist] Status: NAD
+ Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
 
      
-Change 23.3.2.3 [deque.modifiers]:
+The requirement "P shall have a declaration of the form typedef X distribution_- 
+type" effectively makes the use of inheritance for implementing distributions very inconvenient, 
+because the child of a distribution class in general will not satisfy this requirement. In my opinion 
+the benefits of having a typedef in the parameter class pointing back to the distribution class are 
+not worth the hassle this requirement causes. [In my code base I never made use of the nested 
+typedef but on several occasions could have profited from being able to use simple inheritance for 
+the implementation of a distribution class.]
 
      
 
-
      void push_front(const T& x);
-void push_front(T&& x);
-void push_back(const T& x);
-void push_back(T&& x);
-template <class... Args> requires Constructible<T, Args&&...> void push_front(Args&&... args);
-template <class... Args> requires Constructible<T, Args&&...> void push_back(Args&&... args);
-
      
-
 
      
-Change the synopsis in 23.3.4 [list]:
+Proposed resolution: I propose to drop this requirement.
 
      
 
-
      void push_front(const T& x);
-void push_front(T&& x);
-void push_back(const T& x);
-void push_back(T&& x);
-template <class... Args> requires Constructible<T, Args&&...> void push_front(Args&&... args);
-template <class... Args> requires Constructible<T, Args&&...> void push_back(Args&&... args);
-
      
+
      [
+Bellevue:
+]
      
 
-
      
-Change 23.3.4.3 [list.modifiers]:
-
      
 
-
      void push_front(const T& x);
-void push_front(T&& x);
-void push_back(const T& x);
-void push_back(T&& x);
-template <class... Args> requires Constructible<T, Args&&...> void push_front(Args&&... args);
-template <class... Args> requires Constructible<T, Args&&...> void push_back(Args&&... args);
-
      
+
      
+Close NAD for the reasons given in N2424. In practice it is not inconvenient to meet these requirements.
+
      
 
-
      
-Change the synopsis in 23.3.6 [vector]:
-
      
 
-
      void push_back(const T& x);
-void push_back(T&& x);
-template <class... Args> requires Constructible<T, Args&&...> void push_back(Args&&... args);
-
      
 
+
      Proposed resolution:
      
 
      
-Change 23.3.6.4 [vector.modifiers]:
+See N2424
+for the proposed resolution.
 
      
 
-
      void push_back(const T& x);
-void push_back(T&& x);
-template <class... Args> requires Constructible<T, Args&&...> void push_back(Args&&... args);
-
      
 
 
 
 
-
      Rationale:
      
+
      
+
      735. Unfortunate naming
      
+
      Section: 26.5.8.2.2 [rand.dist.bern.bin], 26.5.8.2.4 [rand.dist.bern.negbin] Status: NAD
+ Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
 
      
-Addressed by
-N2680 Proposed Wording for Placement Insert (Revision 1).
+In my opinion the choice of name for the t parameter of the binomial_distribution
+is very unfortunate. In virtually every internet reference, book and software implementation 
+this parameter is called n instead, see for example Wikipedia, Mathworld, Evans et al. (1993) 
+Statistical Distributions, 2nd E., Wiley, p. 38, the R statistical computing language, p. 926, 
+Mathematica and Matlab.
 
      
 
 
      
-If there is still an issue with pair, Howard should submit another issue.
+Similarly, the choice of k for the parameter of the negative binomial distributions is rather unusual. 
+The most common choice for the negative binomial distribution seems to be r instead.
 
      
 
+
      
+Choosing unusual names for the parameters causes confusion among users and makes the 
+interface unnecessarily inconvenient to use.
+
      
 
-
-
-
-
      
-
      773. issues with random
      
-
      Section: 26.5.8.1 [rand.dist.uni] Status: NAD
- Submitter: P.J. Plauger Opened: 2008-01-14  Last modified: 2008-02-27
      
-
      View all other issues in [rand.dist.uni].
      
-
      View all issues with NAD status.
      
-
      Discussion:
      
-
        
-
      1. 
-26.5.8.1.1 [rand.dist.uni.int] uniform_int constructor has changed the default
-max constructor parameter from 9 (in TR1) to max(). The value
-is arbitrary at best and shouldn't be lightly changed because
-it breaks backward compatibility.
-
        2. 
-
-
      2. 
-26.5.8.1.1 [rand.dist.uni.int] uniform_int has a parameter param that you can
-provide on construction or operator(), set, and get. But there
-is not even a hint of what this might be for.
-
        3. 
-
-
      3. 
-26.5.8.1.2 [rand.dist.uni.real] uniform_real. Same issue as #2.
-
        4. 
-
      
+
      
+Possible resolution: For these reasons, I propose to change the name of the respective parameters
+to n and r.
+
      
 
 
      [
 Bellevue:
@@ -14785,12 +16093,15 @@ Bellevue:
 
 
 
      
-NAD. Withdrawn.
+In N2424. NAD It has been around for a while. It is hardly universal,
+there is prior art, and this would confuse people.
 
      
 
 
 
      Proposed resolution:
      
 
      
+See N2424
+for the proposed resolution.
 
      
 
 
@@ -14798,38 +16109,62 @@ NAD. Withdrawn.
 
 
 
      
-
      784. unique_lock::release
      
-
      Section: 30.4.3.2.3 [thread.lock.unique.mod] Status: NAD
- Submitter: Constantine Sapuntzakis Opened: 2008-02-02  Last modified: 2008-02-27
      
+
      736. Comment on [rand.dist.samp.discrete]
      
+
      Section: 26.5.8.5.1 [rand.dist.samp.discrete] Status: NAD
+ Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
      
+
      View all other issues in [rand.dist.samp.discrete].
      
 
      View all issues with NAD status.
      
 
      Discussion:
      
-
      
-unique_lock::release will probably lead to many mistakes where people
-call release instead of unlock. I just coded such a mistake using the
-boost pre-1.35 threads library last week.
-
      
+
        
+
      1. 
+The specification for discrete_distribution requires the member probabilities()
+to return a vector of standardized probabilities, which forces the implementation every time to 
+divide each probability by the sum of all probabilities, as the sum will in practice almost never be 
+exactly 1.0. This is unnecessarily inef ficient as the implementation would otherwise not need to 
+compute the standardized probabilities at all and could instead work with the non-standardized 
+probabilities and the sum. If there was no standardization the user would just get back the 
+probabilities that were previously supplied to the distribution object, which to me seems to be the 
+more obvious solution.
+
        2. 
+
      2. 
+The behaviour of discrete_distribution is not specified in case the number of given
+probabilities is larger than the maximum number representable by the IntType.
+
        3. 
+
      
 
 
      
-In many threading libraries, a call with release in it unlocks the
-lock (e.g. ReleaseMutex in Win32, java.util.concurrent.Semaphore).
+Possible resolution: I propose to change the specification such that the non-standardized 
+probabilities need to be returned and that an additional requirement is included for the number 
+of probabilities to be smaller than the maximum of IntType.
 
      
 
-
      
-I don't call unique_lock::lock much at all, so I don't get to see the
-symmetry between ::lock and ::unlock. I usually use the constructor to
-lock the mutex. So I'm left to remember whether to call release or
-unlock during the few times I need to release the mutex before the scope
-ends. If I get it wrong, the compiler doesn't warn me.
-
      
+
      [
+Stephan Tolksdorf adds pre-Bellevue:
+]
      
+
 
+
      
 
      
-An alternative name for release may be disown.
+In reply to the discussion in 
+N2424
+of this issue:
 
      
-
 
      
-This might be a rare case where usability is hurt by consistency with
-the rest of the C++ standard (e.g. std::auto_ptr::release).
+Rescaled floating-point parameter vectors can not be expected to compare
+equal because of the limited precision of floating-point numbers.
+My proposal would at least guarantee that a parameter
+vector (of type double) passed into the distribution would compare equal
+with the one returned by the probabilities() method. Furthermore, I do
+not understand why "the changed requirement would lead to a significant
+increase in the amount of state in the distribution object". A typical
+implementation's state would increase by exactly one number: the sum of
+all probabilities. The textual representation for serialization would
+not need to grow at all. Finally, the proposed replacement "0 < n <=
+numeric_limits<IntType>::max() + 1" makes the implementation
+unnecessarily complicated, "0 < n <= numeric_limits<IntType>::max()"
+would be better.
 
      
+
      
 
 
      [
 Bellevue:
@@ -14837,178 +16172,139 @@ Bellevue:
 
 
 
      
-Change a name from release to disown. However prior art uses the release
-name. Compatibility with prior art is more important that any possible
-benefit such a change might make. We do not see the benefit for
-changing. NAD
-
      
+
      
+In N2424. We agree with the observation and the proposed resolution to
+part b). We recommend the wording n > 0 be replaced with 0 < n
+numeric_limits::max() + 1. However, we disagree with part a), as it
+would interfere with the definition of parameters' equality. Further,
+the changed requirement would lead to a significant increase in the
+amount of state of the distribution object.
+
      
 
+
      
+As it stands now, it is convenient, and the changes proposed make it
+much less so.
+
      
 
-
      Proposed resolution:
      
 
      
-Change the synopsis in 30.4.3.2 [thread.lock.unique]:
+NAD. Part a the current behavior is desirable. Part b, any constructor
+can fail, but the rules under which it can fail do not need to be listed
+here.
 
      
+
      
 
-
      template <class Mutex> 
-class unique_lock 
-{ 
-public:
-   ...
-   mutex_type* release disown();
-   ...
-};
-
      
 
+
      Proposed resolution:
      
 
      
-Change 30.4.3.2.3 [thread.lock.unique.mod]:
+See N2424
+for the proposed resolution.
 
      
 
-
      mutex_type *release disown();
-
      
-
+
      [
+Stephan Tolksdorf adds pre-Bellevue:
+]
      
 
 
+
      
+
      
+In 26.5.8.5.1 [rand.dist.samp.discrete]:
+
      
 
+
      
+Proposed wording a):
+
      
 
-
      
-
      786. Thread library timed waits, UTC and monotonic clocks
      
-
      Section: 20.9 [time] Status: NAD Editorial
- Submitter: Christopher Kohlhoff, Jeff Garland Opened: 2008-02-03  Last modified: 2008-09-30
      
-
      View all other issues in [time].
      
-
      View all issues with NAD Editorial status.
      
-
      Discussion:
      
+
      
 
      
-The draft C++0x thread library requires that the time points of type
-system_time and returned by get_system_time() represent Coordinated
-Universal Time (UTC) (section X [datetime.system]). This can lead to
-surprising behavior when a library user performs a duration-based wait,
-such as condition_variable::timed_wait(). A complete explanation of the
-problem may be found in the
-Rationale for the Monotonic Clock
-section in POSIX, but in summary:
+Changae in para. 2
 
      
 
-
        
-
      • 
-Operations such as condition_variable::timed_wait() (and its POSIX
-equivalent, pthread_cond_timedwait()) are specified using absolute times
-to address the problem of spurious wakeups.
-
        • 
+
        
+Constructs a discrete_distribution object with n=1 and p0 = w0 = 1
+
        
 
-
      • 
-The typical use of the timed wait operations is to perform a relative
-wait. This may be achieved by first calculating an absolute time as the
-sum of the current time and the desired duration. In fact, the C++0x
-thread library includes duration-based overloads of
-condition_variable::timed_wait() that behave as if by calling the
-corresponding absolute time overload with a time point value of
-get_system_time() + rel_time.
-
        • 
+
        
+and change in para. 5
+
        
 
-
      • 
-A UTC clock may be affected by changes to the system time, such as
-synchronization with an external source, leap seconds, or manual changes
-to the clock.
-
        • 
+
        
+Returns: A vector<double> whose size member returns n and whose
+operator[] member returns pk
+the weight wk as a double value
+when invoked with argument k for k = 0,
+..., n-1
+
        
 
-
      • 
-Should the clock change during a timed wait operation, the actual
-duration of the wait will not be the expected length. For example, a
-user may intend a timed wait of one second duration but, due to an
-adjustment of the system clock backwards by a minute, the wait instead
-takes 61 seconds.
-
        • 
-
      
+
      
 
 
      
-POSIX solves the problem by introducing a new monotonic clock, which is
-unaffected by changes to the system time. When a condition variable is
-initialized, the user may specify whether the monotonic clock is to be
-used. (It is worth noting that on POSIX systems it is not possible to
-use condition_variable::native_handle() to access this facility, since
-the desired clock type must be specified during construction of the
-condition variable object.)
+Proposed wording b):
 
      
 
+
      
 
      
-In the context of the C++0x thread library, there are added dimensions
-to the problem due to the need to support platforms other than POSIX:
+Change in para. 3:
 
      
 
-
        
-
      • 
-Some environments (such as embedded systems) do not have a UTC clock, but do have a monotonic clock.
-
        • 
+
        
+If firstW == lastW, let the sequence w have length n = 1 and consist
+of the single value w0 = 1. Otherwise, [firstW,lastW) shall form a
+sequence w of length n > 0 
+such that 0 < n <= numeric_limits<IntType>::max(),
+and *firstW shall yield a value w0
+convertible to double. [Note: The values wk are commonly known
+as the weights . -- end note]
+
        
 
-
      • 
-Some environments do not have a monotonic clock, but do have a UTC clock.
-
        • 
+
      
 
-
    3. 
-The Microsoft Windows API's synchronization functions use relative
-timeouts based on an implied monotonic clock. A program that switches
-from the Windows API to the C++0x thread library will now find itself
-susceptible to clock changes.
-
      4. 
-
+
      
 
-
      
-One possible minimal solution:
-
      
 
-
        
-
      • 
-Strike normative references to UTC and an epoch based on 1970-01-01.
-
        • 
 
-
      • 
-Make the semantics of system_time and get_system_time()
-implementation-defined (i.e standard library implementors may choose the
-appropriate underlying clock based on the capabilities of the target
-platform).
-
        • 
 
-
      • 
-Add a non-normative note encouraging use of a monotonic clock.
-
        • 
 
+
        
+
        737. Comment on [rand.dist.samp.pconst]
        
+
        Section: 26.5.8.5.2 [rand.dist.samp.pconst] Status: NAD
+ Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
        
+
        View all other issues in [rand.dist.samp.pconst].
        
+
        View all issues with NAD status.
        
+
        Discussion:
        
+
          
 
        1. 
-Remove system_time::seconds_since_epoch().
+The discussion in point T11 above regarding probabilities() similarly applies 
+to the method densities() of piecewise_constant_distribution.
 
          2. 
-
 
        2. 
-Change the constructor explicit system_time(time_t secs, nanoseconds ns
-= 0) to explicit system_time(nanoseconds ns).
+
          
+The design of the constructor
+
          
+
          template <class InputIteratorB, class InputIteratorW> 
+piecewise_constant_distribution( InputIteratorB firstB, InputIteratorB lastB, 
+                                 InputIteratorW firstW);
+
          
+
          
+is unnecessarily unsafe, as there is no separate end-iterator given for the weights. I can't see 
+any performance or convenience reasons that would justify the risks inherent in such a function 
+interface, in particular the risk that input error might go unnoticed.
+
          
 
          3. 
-
      
-
-
+
    
 
-
    Proposed resolution:
    
 
    
+Possible resolution: I propose to add an InputIteratorW lastW argument to the interface.
 
    
 
+
    [
+Stephan Tolksdorf adds pre-Bellevue:
+]
    
 
-
    Rationale:
    
-Addressed by
-N2661: A Foundation to Sleep On.
-
-
-
-
-
-
    
-
    790. xor_combine::seed not specified
    
-
    Section: X [rand.adapt.xor] Status: NAD
- Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2008-02-27
    
-
    View all other issues in [rand.adapt.xor].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
-
    
-xor_combine::seed(result_type) and seed(seed_seq&) don't say what
-happens to each of the sub-engine seeds. (Should probably do the same
-to both, unlike TR1.)
-
    
+
    
+In reply to the discussion in
+N2424
+I'd like to make the same comments as for 736.
+
    
 
 
    [
 Bellevue:
@@ -15016,82 +16312,82 @@ Bellevue:
 
 
 
    
-Overcome by the previous proposal. NAD mooted by resolution of 789.
+In N2424. There is already precedent elsewhere in the library. Follows existing convention. NAD.
 
    
 
 
-
 
    Proposed resolution:
    
-
-
-
-
-
-
    
-
    791. piecewise_constant_distribution::densities has wrong name
    
-
    Section: 26.5.8.5.2 [rand.dist.samp.pconst] Status: NAD
- Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2008-03-11
    
-
    View all other issues in [rand.dist.samp.pconst].
    
-
    View all issues with NAD status.
    
-
    Discussion:
    
 
    
-piecewise_constant_distribution::densities() should be probabilities(),
-just like discrete_distribution. (There's no real use for weights divided
-by areas.)
+See N2424
+for the proposed resolution.
 
    
 
 
    [
-Bellevue:
+Stephan Tolksdorf adds pre-Bellevue:
 ]
    
 
 
 
    
 
    
-Fermilab does not agree with this summary. As defined in the equation in
-26.4.8.5.2/4, the quantities are indeed probability densities not
-probabilities. Because we view this distribution as a parameterization
-of a *probability density function*, we prefer to work in terms of
-probability densities.
+In 26.5.8.5.2 [rand.dist.samp.pconst]:
 
    
 
 
    
-We don't think this should be changed.
+Proposed wording a)
 
    
 
+
    
 
    
-If there is a technical argument about why the implementation dealing
-with these values can't be as efficient as one dealing with
-probabilities, we might reconsider. We don't care about this one member
-function being somewhat more or less efficient; we care about the size
-of the distribution object and the speed of the calls to generate
-variates.
+Change in para. 2
 
    
+
    
+Constructs a piecewise_constant_distribution object with n = 1, p0 = w0 = 1,
+b0 = 0, and b1 = 1
 
    
 
+
    
+and change in para. 5
+
    
 
+
    
+A vector<result_type> whose size member returns n and whose operator[]
+member returns pk
+the weight wk as a double value
+when invoked with argument k for k = 0, ..., n-1
+
    
 
-
    Proposed resolution:
    
+
    
 
 
    
-Change synopsis in 26.5.8.5.2 [rand.dist.samp.pconst]:
+Proposed wording b)
 
    
 
-
    template <class RealType = double> 
-class piecewise_constant_distribution 
-{ 
-public:
-    ...
-    vector<double> densities probabilities() const;
-    ...
-};
-
    
+
    
+
    
+Change both occurrences of
+
    
+
+
    
+"piecewise_constant_distribution(InputIteratorB firstB, InputIteratorB lastB,
+                                 InputIteratorW firstW, InputIteratorW lastW)
+
    
 
 
    
-Change 26.5.8.5.2 [rand.dist.samp.pconst]/6:
+and change in para. 3
 
    
 
-
    vector<double> densities probabilities() const;
-
    
+
    
+the length of the sequence w starting from firstW shall be at least n,
+*firstW shall return a value w0 that is convertible to double, and any
+wk for k >= n shall be ignored by the distribution
+[firstW, lastW) shall form a sequence w of length n whose leading element
+w0 shall be convertible to double
+
    
+
+
    
+
+
+
    
 
 
 
@@ -15099,23 +16395,44 @@ Change 26.5.8.5.2 [rand.dist.samp.pconst]/6:
 
 
 
    
-
    793. discrete_distribution missing constructor
    
-
    Section: 26.5.8.5.1 [rand.dist.samp.discrete] Status: NAD Editorial
- Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2009-03-09
    
-
    View all other issues in [rand.dist.samp.discrete].
    
+
    738. Editorial issue in [rand.adapt.disc]/3
    
+
    Section: 26.5.4.1 [rand.adapt.disc] Status: NAD Editorial
+ Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-09-22
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
 
    
-discrete_distribution should have a constructor like:
+Since the template parameter p and r are of type size_t, the member n in the class 
+exposition should have type size_t, too.
 
    
 
-
    template<class _Fn>
-  discrete_distribution(result_type _Count, double _Low, double _High,
-                        _Fn& _Func);
-
    
 
+
    Proposed resolution:
    
 
    
-(Makes it easier to fill a histogram with function values over a range.)
+See N2424
+for the proposed resolution.
+
    
+
+
+
+
+
+
    
+
    739. Defect in [rand.util.canonical]/3
    
+
    Section: 26.5.7.2 [rand.util.canonical] Status: NAD
+ Submitter: Stephan Tolksdorf Opened: 2007-09-21  Last modified: 2008-02-27
    
+
    View all other issues in [rand.util.canonical].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
+
    
+The complexity of generate_canonical is specified to be "exactly k=max(1, ceil(b/log2 
+R)) invocations of g". This terms involves a logarithm that is not rounded and hence can not (in 
+general) be computed at compile time. As this function template is performance critical, I propose 
+to replace ceil(b/log2 R) with ceil(b/floor(log2 R)).
+
    
+
+
    
+See N2424
+for further discussion.
 
    
 
 
    [
@@ -15124,521 +16441,327 @@ Bellevue:
 
 
 
    
-How do you specify the function so that it does not return negative
-values? If you do it is a bad construction. This requirement is already
-there. Where in each bin does one evaluate the function? In the middle.
-Need to revisit tomorrow.
+In N2424. Close NAD as described there.
 
    
 
-
    [
-Sophia Antipolis:
-]
    
 
 
-
    
+
    Proposed resolution:
    
 
    
-Bill is not requesting this.
+See N2424
+for the proposed resolution.
 
    
+
+
+
+
+
+
    
+
    741. Const-incorrect get_deleter function for shared_ptr
    
+
    Section: 20.8.10.2.11 [util.smartptr.getdeleter] Status: NAD
+ Submitter: Daniel Krügler Opened: 2007-09-27  Last modified: 2008-02-27
    
+
    View all other issues in [util.smartptr.getdeleter].
    
+
    View all issues with NAD status.
    
+
    Discussion:
    
 
    
-Marc Paterno: _Fn cannot return negative values at the points where the
-function is sampled. It is sampled in the middle of each bin. _Fn cannot
-return 0 everywhere it is sampled.
+The following issue was raised by Alf P. Steinbach in c.l.c++.mod:
 
    
+
 
    
-Jens: lambda expressions are rvalues
+According to the recent draft N2369, both the header memory synopsis
+of 20.8 [memory] and 20.8.10.2.11 [util.smartptr.getdeleter] declare:
 
    
+
+
    template<class D, class T> D* get_deleter(shared_ptr<T> const& p);
+
    
+
 
    
-Add a library issue to provide an
-initializer_list<double> constructor for
-discrete_distribution.
-
    
-
    
-Marc Paterno: dislikes reference for _Fn parameter. Make it pass-by-value (to use lambda),
-use std::ref to wrap giant-state function objects.
-
    
-
    
-Daniel: See random_shuffle, pass-by-rvalue-reference.
-
    
-
    
-Daniel to draft wording.
-
    
-
    
-
-
    [
-Pre San Francisco, Daniel provided wording:
-]
    
-
-
-
    
-The here proposed changes of the WP refer to the current state of
-N2691.
-During the Sophia Antipolis meeting two different proposals came up
-regarding the functor argument type, either by value or by rvalue-reference.
-For consistence with existing conventions (state-free algorithms and the
-general_pdf_distribution c'tor signature) the author decided to propose a
-function argument that is provided by value. If severe concerns exists that
-stateful functions would be of dominant relevance, it should be possible to
-replace the two occurrences of Func by Func&& in this proposal as part
-of an editorial process.
-
    
-
-
-
-
    Proposed resolution:
    
-
-
    Non-concept version of the proposed resolution
    
-
-
      
-
    1. 
-
      
-In 26.5.8.5.1 [rand.dist.samp.discrete]/1, class discrete_distribution, just
-before the member declaration
+This allows to retrieve the pointer to a mutable deleter of a const
+shared_ptr (if that owns one) and therefore contradicts the usual
+philosophy that associated functors are either read-only (e.g.
+key_comp or value_comp of std::map) or do at least reflect
+the mutability of the owner (as seen for the both overloads of
+unique_ptr::get_deleter).
+Even the next similar counter-part of get_deleter - the two
+overloads of function::target in the class template function
+synopsis 20.7.16.2 [func.wrap.func] or in 20.7.16.2.5 [func.wrap.func.targ] - do
+properly mirror the const-state of the owner.
 
      
 
-
      explicit discrete_distribution(const param_type& parm);
-
      
+Possible proposed resolutions:
 
 
      
-insert:
+Replace the declarations of get_deleter in the header <memory>
+synopsis of 20.8 [memory] and in 20.8.10.2.11 [util.smartptr.getdeleter] by one of the
+following alternatives (A) or (B):
 
      
 
+
        
+
      1. 
+Provide only the immutable variant. This would reflect the
+current praxis of container::get_allocator(), map::key_comp(), or
+map::value_comp.
 
-
        template<typename Func>
-discrete_distribution(result_type nf, double xmin, double xmax, Func fw);
+
        template<class D, class T> const D* get_deleter(shared_ptr<T> const& p);
 
        
 
        2. 
-
 
      2. 
+Just remove the function.
+
        3. 
+
      
+
 
      
-Between p.4 and p.5 insert a series of new paragraphs as part of the
-new member description::
+Alberto Ganesh Barbati adds:
 
      
-
      template<typename Func>
-discrete_distribution(result_type nf, double xmin, double xmax, Func fw);
-
      
 
+
        
+
      1. 
 
        
-Complexity: Exactly nf invocations of fw.
+Replace it with two functions:
 
        
+
        template <class D, class T> D get_deleter(shared_ptr<T> const&);
+template <class D, class T> bool has_deleter(shared_ptr<T> const&);
+
        
+
 
        
-Requires:
+The first one would throw if D is the wrong type, while the latter would
+never throw. This approach would reflect the current praxis of
+use_facet/has_facet, with the twist of returning the deleter by value as
+container::get_allocator() do.
 
        
-
          
-
        1. 
-fw shall be callable with one argument of type double, and shall
-return values of a type convertible to double;
          2. 
-
-
        2. If nf > 0, the relation xmin < xmax shall hold, and for all sample values
-xk, fw(xk) shall return a weight value wk that is non-negative, non-NaN,
-and non-infinity;
          3. 
-
-
        3. The following relations shall hold: nf ≥ 0, and 0 < S = w0+. . .+wn-1.
          4. 
-
+
 
        
 
 
        
-Effects:
+Peter Dimov adds:
 
        
-
          
-
        1. If nf == 0, sets n = 1 and lets the sequence w have length n = 1 and
-   consist of the single value w0 = 1.
          2. 
 
-
        2. 
-
          Otherwise, sets n = nf, deltax = (xmax - xmin)/n and xcent = xmin +
-0.5 * deltax.
          
-
          For each k = 0, . . . ,n-1, calculates:
-  xk = xcent + k * deltax
-  wk = fw(xk)
-
          
-
          3. 
-
        3. 
-
          Constructs a discrete_distribution object with probabilities:
          
-
          pk = wk/S  for k = 0, . . . , n-1.
-
          
-
          4. 
-
        
+
        
+
        
+My favorite option is "not a defect". A, B and C break useful code.
+
        
 
        
-
        2. 
-
      
 
-
      Concept version of the proposed resolution
      
+
      [
+Bellevue:
+]
      
 
 
-
        
-
      1. 
-
        
-In 26.5.8.5.1 [rand.dist.samp.discrete]/1, class discrete_distribution, just
-before the member declaration
-
        
+
        
+Concern this is similar to confusing "pointer to const" with "a constant pointer".
+
        
 
-
        explicit discrete_distribution(const param_type& parm);
-
        
 
+
        Proposed resolution:
        
 
        
-insert:
 
        
 
 
-
        template<Callable<auto, double> Func>
- requires Convertible<Func::result_type, double>
-discrete_distribution(result_type nf, double xmin, double xmax, Func fw);
-
        
-
        2. 
 
-
      2. 
-
        
-Between p.4 and p.5 insert a series of new paragraphs as part of the
-new member description::
-
        
-
        template<Callable<auto, double> Func>
- requires Convertible<Func::result_type, double>
-discrete_distribution(result_type nf, double xmin, double xmax, Func fw);
-
        
 
+
+
        
+
        745. copy_exception API slices.
        
+
        Section: 18.8.5 [propagation] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2007-10-10  Last modified: 2008-02-25
        
+
        View other active issues in [propagation].
        
+
        View all other issues in [propagation].
        
+
        View all issues with NAD status.
        
+
        Discussion:
        
 
        
-Complexity: Exactly nf invocations of fw.
+It could be I did not understand the design rationale, but I thought
+copy_exception would produce an exception_ptr to the most-derived (dynamic)
+type of the passed exception.  Instead it slices, which appears to be less
+useful, and a likely source of FAQ questions in the future.
 
        
 
        
-Requires:
+(Peter Dimov suggests NAD)
 
        
-
          
-
        1. If nf > 0, the relation xmin < xmax shall hold, and for all sample values
-xk, fw(xk) shall return a weight value wk that is non-negative, non-NaN,
-and non-infinity;
          2. 
 
-
        2. The following relations shall hold: nf ≥ 0, and 0 < S = w0+. . .+wn-1.
          3. 
+
          [
+Bellevue: 
+]
          
 
-
        
 
+
        
 
        
-Effects:
+How could this be implemented in a way that the dynamic type is cloned?
+
        
+
        
+The feature is designed to create an exception_ptr from an object whose
+static type is identical to the dynamic type and thus there is no
+slicing involved.
 
        
-
          
-
        1. If nf == 0, sets n = 1 and lets the sequence w have length n = 1 and
-   consist of the single value w0 = 1.
          2. 
-
-
        2. 
-
          Otherwise, sets n = nf, deltax = (xmax - xmin)/n and xcent = xmin +
-0.5 * deltax.
          
-
          For each k = 0, . . . ,n-1, calculates:
-  xk = xcent + k * deltax
-  wk = fw(xk)
-
          
-
          3. 
-
        3. 
-
          Constructs a discrete_distribution object with probabilities:
          
-
          pk = wk/S  for k = 0, . . . , n-1.
-
          
-
          4. 
-
        
 
        
-
        3. 
-
      
 
 
-
-
      Rationale:
      
-Addressed by
-N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
+
      Proposed resolution:
      
+
      
+
      
 
 
 
 
 
 
      
-
      794. piecewise_constant_distribution missing constructor
      
-
      Section: 26.5.8.5.2 [rand.dist.samp.pconst] Status: NAD Editorial
- Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2009-03-09
      
-
      View all other issues in [rand.dist.samp.pconst].
      
-
      View all issues with NAD Editorial status.
      
+
      747. We have 3 separate type traits to identify classes supporting no-throw operations
      
+
      Section: 20.6.4.3 [meta.unary.prop] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2007-10-10  Last modified: 2009-07-16
      
+
      View other active issues in [meta.unary.prop].
      
+
      View all other issues in [meta.unary.prop].
      
+
      View all issues with NAD status.
      
 
      Discussion:
      
 
      
-piecewise_constant_distribution should have a constructor like:
+We have 3 separate type traits to identify classes supporting no-throw
+operations, which are very useful when trying to provide exception safety
+guarantees.  However, I'm not entirely clear on what the current wording
+requires of a conforming implementation.  To quote from
+has_nothrow_default_constructor:
+
      
+
      
+or T is a class type with a default constructor that is known not to throw
+any exceptions
+
      
+
      
+What level of magic do we expect to deduce if this is known?
+
      
+
      
+E.g.
 
      
 
-
      template<class _Fn>
-   piecewise_constant_distribution(size_t _Count,
-            _Ty _Low, _Ty _High, _Fn& _Func);
+
      struct test{
+ int x;
+ test() : x() {}
+};
 
      
-
 
      
-(Makes it easier to fill a histogram with function values over a range.
-The two (reference 793) make a sensible replacement for
-general_pdf_distribution.)
+Should I expect a conforming compiler to 
+ assert( has_nothrow_constructor<test>::value )
 
      
-
-
      [
-Sophia Antipolis:
-]
      
-
-
-
      
 
      
-Marc: uses variable width of bins and weight for each bin. This is not
-giving enough flexibility to control both variables.
+Is this a QoI issue?
 
      
 
      
-Add a library issue to provide an constructor taking an
-initializer_list<double> and _Fn for piecewise_constant_distribution.
+Should I expect to 'know' only if-and-only-if there is an inline definition
+available?
 
      
 
      
-Daniel to draft wording.
+Should I never expect that to be true, and insist that the user supplies an
+empty throw spec if they want to assert the no-throw guarantee?
 
      
-
      
-
-
      [
-Pre San Francisco, Daniel provided wording.
+
      
+It would be helpful to maybe have a footnote explaining what is required,
+but right now I don't know what to suggest putting in the footnote.
+
      
+
      
+(agreement since is that trivial ops and explicit no-throws are required.
+Open if QoI should be allowed to detect further)
+
      
+
+
      [
+Bellevue:
 ]
      
 
 
 
      
-The here proposed changes of the WP refer to the current state of
-N2691.
-For reasons explained in 793, the author decided to propose a function
-argument that is provided by value. The issue proposes a c'tor signature,
-that does not take advantage of the full flexibility of
-piecewise_constant_distribution,
-because it restricts on a constant bin width, but the use-case seems to
-be popular enough to justify it's introduction.
+This looks like a QoI issue.
+In the case of trivial and nothrow it is known. Static analysis of the program is definitely into QoI.
+Move to OPEN. Need to talk to Core about this.
 
      
 
+
      [
+2009-07 Frankfurt:
+]
      
 
 
-
      Proposed resolution:
      
-
-
      Non-concept version of the proposed resolution
      
-
-
        
-
      1. 
-
        
-In 26.5.8.5.2 [rand.dist.samp.pconst]/1, class piecewise_constant_distribution,
-just before the member declaration
-
        
-
-
        explicit piecewise_constant_distribution(const param_type& parm);
-
        
-
        
-insert:
-
        
-
        template<typename Func>
-piecewise_constant_distribution(size_t nf, RealType xmin, RealType xmax, Func fw);
-
        
-
        2. 
-
-
      2. 
-
        
-Between p.4 and p.5 insert a new sequence of paragraphs nominated
-below as [p5_1], [p5_2],
-[p5_3], and [p5_4] as part of the new member description:
-
        
-
-
        template<typename Func>
-piecewise_constant_distribution(size_t nf, RealType xmin, RealType xmax, Func fw);
-
        
 
        
 
        
-[p5_1] Complexity: Exactly nf invocations of fw.
-
        
-
        
-[p5_2] Requires:
-
        
-
          
-
        1. fw shall be callable with one argument of type RealType, and shall
-return values of a type convertible to double;
-
          2. 
-
        2. 
-For all sample values xk defined below, fw(xk) shall return a weight
-value wk that is non-negative, non-NaN, and non-infinity;
-
          3. 
-
        3. 
-The following relations shall hold: xmin < xmax, and
-0 < S = w0+. . .+wn-1.
-
          4. 
-
        
-
        
-[p5_3] Effects:
+This is QoI.
 
        
-
          
-
        1. 
-
          If nf == 0,
          
- 
            
- 
          1. 
-sets deltax = xmax - xmin, and
            2. 
-
          2.  lets the sequence w have length n = 1 and consist of the single
-    value w0 = 1, and
            3. 
-
          3.  lets the sequence b have length n+1 with b0 = xmin and 
-              b1 = xmax
-
            4. 
-
          
-
          2. 
-
        2. 
-
          Otherwise,
          
-
            
-
          1.  sets n = nf, deltax = (xmax - xmin)/n,
-                 xcent = xmin + 0.5 * deltax, and
-
            2. 
-
          2. lets the sequences w and b have length n and n+1, resp. and
            
-
            for each k = 0, . . . ,n-1, calculates:
-  dxk = k * deltax
-  bk = xmin + dxk
-  xk = xcent + dxk
-  wk = fw(xk),
-
             
-
             and
            
-
            3. 
-
          3.  sets bn = xmax
            4. 
-
          
-
          3. 
-
        3. 
 
          
-Constructs a piecewise_constant_distribution object with
-the above computed sequence b as the interval boundaries
-and with the probability densities:
+Move to NAD.
 
          
-
          ρk = wk/(S * deltax)  for k = 0, . . . , n-1.
-
           
-
          4. 
-
        
-
        
-[p5_4] [Note: In this context, the subintervals [bk, bk+1) are commonly
- known as the bins of a histogram. -- end note]
- 
        
 
        
-
        
-
        3. 
-
      
 
-
      Concept version of the proposed resolution
      
 
-
        
-
      1. 
+
        Proposed resolution:
        
 
        
-In 26.5.8.5.2 [rand.dist.samp.pconst]/1, class piecewise_constant_distribution,
-just before the member declaration
 
        
 
-
        explicit piecewise_constant_distribution(const param_type& parm);
-
        
-
        
-insert:
-
        
-
        template<Callable<auto, RealType> Func>
- requires Convertible<Func::result_type, double>
-piecewise_constant_distribution(size_t nf, RealType xmin, RealType xmax, Func fw);
-
        
-
        2. 
 
-
      2. 
-
        
-Between p.4 and p.5 insert a new sequence of paragraphs nominated
-below as [p5_1], [p5_2],
-[p5_3], and [p5_4] as part of the new member description:
-
        
 
-
        template<Callable<auto, RealType> Func>
- requires Convertible<Func::result_type, double>
-piecewise_constant_distribution(size_t nf, RealType xmin, RealType xmax, Func fw);
-
        
-
        
-
        
-[p5_1] Complexity: Exactly nf invocations of fw.
-
        
+
+
+
        
+
        748. The is_abstract type trait is defined by reference to 10.4.
        
+
        Section: 20.6.4.3 [meta.unary.prop] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2007-10-10  Last modified: 2009-05-01
        
+
        View other active issues in [meta.unary.prop].
        
+
        View all other issues in [meta.unary.prop].
        
+
        View all issues with NAD status.
        
+
        Discussion:
        
 
        
-[p5_2] Requires:
+I am trying to decide is a pure virtual function is a necessary as well as
+sufficient requirement to be classified as abstract?
 
        
-
          
-
        1. 
-For all sample values xk defined below, fw(xk) shall return a weight
-value wk that is non-negative, non-NaN, and non-infinity;
-
          2. 
-
        2. 
-The following relations shall hold: xmin < xmax, and
-0 < S = w0+. . .+wn-1.
-
          3. 
-
        
 
        
-[p5_3] Effects:
+For instance, is the following (non-polymorphic) type considered abstract?
 
        
-
          
-
        1. 
-
          If nf == 0,
          
- 
            
- 
          1. 
-sets deltax = xmax - xmin, and
            2. 
-
          2.  lets the sequence w have length n = 1 and consist of the single
-    value w0 = 1, and
            3. 
-
          3.  lets the sequence b have length n+1 with b0 = xmin and 
-              b1 = xmax
-
            4. 
-
          
-
          2. 
-
        2. 
-
          Otherwise,
          
-
            
-
          1.  sets n = nf, deltax = (xmax - xmin)/n,
-                 xcent = xmin + 0.5 * deltax, and
-
            2. 
-
          2. lets the sequences w and b have length n and n+1, resp. and
            
-
            for each k = 0, . . . ,n-1, calculates:
-  dxk = k * deltax
-  bk = xmin + dxk
-  xk = xcent + dxk
-  wk = fw(xk),
-
             
-
             and
            
-
            3. 
-
          3.  sets bn = xmax
            4. 
-
          
-
          3. 
-
        3. 
+
          struct abstract {
+protected:
+ abstract(){}
+ abstract( abstract const & ) {}
+ ~abstract() {}
+};
+
          
 
          
-Constructs a piecewise_constant_distribution object with
-the above computed sequence b as the interval boundaries
-and with the probability densities:
+(Suggested that this may be NAD, with an editorial fix-up from Pete on the
+core wording to make clear that abstract requires a pure virtual function)
 
          
-
          ρk = wk/(S * deltax)  for k = 0, . . . , n-1.
-
           
-
          4. 
-
        
-
        
-[p5_4] [Note: In this context, the subintervals [bk, bk+1) are commonly
- known as the bins of a histogram. -- end note]
- 
        
-
        
-
        
-
        3. 
-
      
 
 
-
-
      Rationale:
      
-Addressed by
-N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
+
      Proposed resolution:
      
+
      
+Core has clarified that the definition abstract is adequate. Issue withdrawn by submitter. NAD.
+
      
 
 
 
 
 
 
      
-
      795. general_pdf_distribution should be dropped
      
-
      Section: X [rand.dist.samp.genpdf] Status: Dup
- Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2008-03-11
      
-
      View all other issues in [rand.dist.samp.genpdf].
      
+
      750. The current definition for is_convertible requires that the type be
+implicitly convertible, so explicit constructors are ignored.
      
+
      Section: 20.6.5 [meta.rel] Status: Dup
+ Submitter: Alisdair Meredith Opened: 2007-10-10  Last modified: 2009-07-16
      
+
      View all other issues in [meta.rel].
      
 
      View all issues with Dup status.
      
-
      Duplicate of: 732
      
+
      Duplicate of: 719
      
 
      Discussion:
      
 
      
-general_pdf_distribution should be dropped. (It's a research topic in
-adaptive numerical integration.)
+With the pending arrival of explicit conversion functions though, I'm
+wondering if we want an additional trait, is_explictly_convertible?
 
      
 
 
      [
-Stephan Tolksdorf notes:
+Bellevue:
 ]
      
 
 
 
      
-This appears to be a duplicate of 732.
+Alisdair is considering preparing a paper listing a number of missing
+type traits, and feels that it might be useful to handle them all
+together rather than piecemeal. This would affect issue 719 and 750.
+These two issues should move to OPEN pending AM paper on type traits.
+
      
+
+
      [
+2009-07 Frankfurt:
+]
      
+
+
+
      
+Duplicate of 719 (for our purposes).
 
      
 
 
@@ -15650,473 +16773,512 @@ This appears to be a duplicate of 796. ranlux48_base returns wrong value
-
      Section: 26.5.5 [rand.predef] Status: NAD
- Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2008-02-27
      
-
      View all other issues in [rand.predef].
      
+
      751. change pass-by-reference members of vector<bool> to pass-by-value?
      
+
      Section: 23.3.7 [vector.bool] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2007-10-10  Last modified: 2009-07-16
      
+
      View all other issues in [vector.bool].
      
 
      View all issues with NAD status.
      
 
      Discussion:
      
 
      
-The 10,000th value returned by ranlux48_base is supposed to be
-61839128582725. We get 192113843633948. (Note that the underlying
-generator was changed in Kona.)
+A number of vector<bool> members take const bool& as arguments.
+Is there any chance we could change them to pass-by-value or would I 
+be wasting everyone's time if wrote up an issue?
 
      
 
 
      [
-Bellevue:
+post Bellevue:
 ]
      
 
 
 
      
-Submitter withdraws defect.
-
      
-
-
-
-
      Proposed resolution:
      
 
      
-Change 26.5.5 [rand.predef]/p5:
+As we understand it, the original requester (Martin Sebor) would like
+for implementations to be permitted to pass-by-value. Alisdair suggests
+that if this is to be resolved, it should be resolved more generally,
+e.g. in other containers as well.
+
      
+
      
+We note that this would break ABI. However, we also suspect that this
+might be covered under the "as-if" rule in section 1.9.
+
      
+
      
+Many in the group feel that for vector<bool>, this is a "don't care",
+and that at this point in the process it's not worth the bandwidth.
+
      
+
      
+Issue 679 -- which was in ready status pre-Bellevue and is
+now in the working paper -- is related to this, though not a duplicate.
+
      
+
      
+Moving to Open with a task for Alisdair to craft a informative note to
+be put whereever appropriate in the WP. This note would clarify places
+where pass-by-const-ref can be transformed to pass-by-value under the
+as-if rule.
 
      
-
-
      
-
      typedef subtract_with_carry_engine<uint_fast64_t, 48, 5, 12> 
-        ranlux48_base; 
-
      
-
      
-Required behavior: The 10000th consecutive invocation of a default-constructed
-object of type ranlux48_base shall produce the value
-61839128582725 192113843633948.
-
      
 
      
 
+
      [
+San Francisco:
+]
      
 
 
-
-
-
      
-
      797. ranlux48 returns wrong value
      
-
      Section: 26.5.5 [rand.predef] Status: NAD
- Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2008-02-27
      
-
      View all other issues in [rand.predef].
      
-
      View all issues with NAD status.
      
-
      Discussion:
      
+
      
 
      
-The 10,000th value returned by ranlux48 is supposed to be
-249142670248501. We get 88229545517833. (Note that this depends
-on ranlux48_base.)
+This is really a clause 17 issue, rather than something specific to vector<bool>.
+
      
+
      
+Move to Open. Alisdair to provide a resolution. Alternately, Howard can
+close this as NAD and then open a new issue to handle the general issue
+(rather than the vector<bool> one).
+
      
+
      
+Howard:  Haven't yet opened new issue.  Lacking wording for it.
 
      
+
      
+
 
      [
-Bellevue:
+2009-07 Frankfurt:
 ]
      
 
 
 
      
-Submitter withdraws defect.
+NAD.  Insufficient motivation to make any changes.
 
      
 
 
-
 
      Proposed resolution:
      
 
      
-Change 26.5.5 [rand.predef]/p6:
 
      
 
-
      
-
      typedef discard_block_engine<ranlux48_base, 389, 11> 
-        ranlux48
-
      
-
      
-Required behavior: The 10000th consecutive invocation of a default-constructed
-object of type ranlux48 shall produce the value
-249142670248501 88229545517833.
-
      
-
      
-
 
 
 
 
 
      
-
      799. [tr.rand.eng.mers] and [rand.eng.mers]
      
-
      Section: 26.5.3.2 [rand.eng.mers], TR1 5.1.4.2 [tr.rand.eng.mers] Status: NAD
- Submitter: Stephan Tolksdorf Opened: 2008-02-18  Last modified: 2008-03-11
      
-
      View all other issues in [rand.eng.mers].
      
-
      View all issues with NAD status.
      
+
      754. Ambiguous return clause for std::uninitialized_copy
      
+
      Section: 20.8.8.2 [uninitialized.copy] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2007-10-15  Last modified: 2008-07-02
      
+
      View all other issues in [uninitialized.copy].
      
+
      View all issues with NAD Editorial status.
      
 
      Discussion:
      
 
      
-TR1 5.1.4.2 [tr.rand.eng.mers](10) requires that operator== for the mersenne_twister
-returns true if and only if the states of two mersenne_twisters,
-consisting each of n integers between 0 and 2w - 1, are completely
-equal. This is a contradiction with TR1 5.1.1 [tr.rand.req](3) because the given
-definition of the state also includes the lower r bits of x(i-n), which
-will never be used to generate a random number. If two mersenne_twisters
-only differ in the lower bits of x(i-n) they will not compare equal,
-although they will produce an identical sequence of random numbers.
+14882-2003, [lib.uninitialized.copy] is currently written as follows:
 
      
 
+
      
+
      template <class InputIterator, class ForwardIterator>
+  ForwardIterator uninitialized_copy(InputIterator first, InputIterator last,
+                                     ForwardIterator result);
+
      
+
      
 
      
-26.5.3.2 [rand.eng.mers] in the latest C++ draft does not specify the behaviour
-of operator== but uses a similar definition of the state and, just like
-TR1 5.1.4.2 [tr.rand.eng.mers], requires the textual representation of a
-mersenne_twister_engine to consist of Xi-n to Xi-1, including the
-lower bits of Xi-n. This leads to two problems: First, the
-unsuspecting implementer is likely to erroneously compare the lower r
-bits of Xi-n in operator==. Second, if only the lower r bits differ,
-two mersenne_twister_engines will compare equal (if correctly
-implemented) but have different textual representations, which
-conceptually is a bit ugly.
+-1- Effects:
 
      
-
+
      for (; first != last; ++result, ++first)
+  new (static_cast<void*>(&*result))
+    typename iterator_traits<ForwardIterator>::value_type(*first);
+
      
 
      
-I propose that a paragraph or footnote is added to 26.5.3.2 [rand.eng.mers] which
-clarifies that the lower r bits of Xi-n are not to be compared in
-operator== and operator!=. It would only be consequent if furthermore
-the specification for the textual respresentation was changed to
-Xi-n bitand ((2w - 1) - (2r - 1)), Xi-(n-1), ...,  Xi-1 or
-something similar.
+-2- Returns: result
 
      
+
      
+
      
 
 
      
-These changes would likely have no practical effect, but would allow an
-implementation that does the right thing to be standard-conformant.
+similarily for N2369, and its corresponding section
+20.8.8.2 [uninitialized.copy].
 
      
 
-
      [
-Bellevue:
-]
      
-
-
-
      
-
      
-Fermi Lab has no objection to the proposed change. However it feels that
-more time is needed to check the details, which would suggest a change
-to REVIEW.
-
      
 
      
-Bill feels that this is NAD, not enough practical importance to abandon
-the simple definition of equality, and someone would have to do a lot
-more study to ensure that all cases are covered for a very small
-payback. The submitter admits that "These changes would likely have no
-practical effect,", and according to Plum's razor this means that it is
-not worth the effort!
+It's not clear to me what the return clause is supposed to mean, I see
+two
+possible interpretations:
 
      
+
+
        
+
      1. 
+The notion of result is supposed to mean the value given by the
+function parameter result [Note to the issue editor: Please use italics for
+result].
+This seems somewhat implied by recognizing that both the function
+parameter
+and the name used in the clause do have the same italic font.
+
        2. 
+
      2. 
+The notion of "result" is supposed to mean the value of result
+after the
+preceding effects clause. This is in fact what all implementations I
+checked
+do (and which is probably it's intend, because it matches the
+specification of std::copy).
+
        3. 
+
      
+
 
      
-Revisted: Agree that the fact that there is no practical difference means that no change can be justified.
+The problem is: I see nothing in the standard which grants that this
+interpretation
+is correct, specifically [lib.structure.specifications] or
+17.5.1.4 [structure.specifications]
+resp. do not clarify which "look-up" rules apply for names found in
+the elements
+of the detailed specifications - Do they relate to the corresponding
+synopsis or
+to the effects clause (or possibly other elements)? Fortunately most
+detailed
+descriptions are unambigious in this regard, e.g. this problem does
+not apply
+for std::copy.
 
      
-
      
+
 
 
 
      Proposed resolution:
      
 
      
-In 26.5.3.2 [rand.eng.mers]:
+Change the wording of the return clause to say (20.8.8.2 [uninitialized.copy]):
 
      
 
 
      
 
      
-Insert at the end of para 2.:
+-2- Returns: The value of result after effects have taken place.
 
      
-
-
      
-[Note: The lower r bits of Xi-n do not influence
-the state transition and hence should not be compared when comparing two
-mersenne_twister_engine objects. -- end note]
 
      
 
-
      
-In para 5. change:
-
      
+
+
      [
+Bellevue:
+]
      
+
 
 
      
-The textual representation of xi consists of the values of
-Xi-n bitand ((2w - 1) - (2r - 1)),  Xi-(n-1),
-..., Xi-1, in that order.
-
      
+Resolution: NAD editorial -- project editor to decide if change is
+worthwhile. Concern is that there are many other places this might
+occur.
 
      
 
 
 
 
-
 
      
-
      800. Issues in 26.4.7.1 [rand.util.seedseq](6)
      
-
      Section: 26.5.7.1 [rand.util.seedseq] Status: NAD Editorial
- Submitter: Stephan Tolksdorf Opened: 2008-02-18  Last modified: 2009-03-09
      
-
      View all other issues in [rand.util.seedseq].
      
+
      756. Container adaptors push
      
+
      Section: 23.3.5 [container.adaptors] Status: NAD Editorial
+ Submitter: Paolo Carlini Opened: 2007-10-31  Last modified: 2008-06-18
      
 
      View all issues with NAD Editorial status.
      
 
      Discussion:
      
 
      
-The for-loop in the algorithm specification has n iterations, where n is
-defined to be end - begin, i.e. the number of supplied w-bit quantities.
-Previous versions of this algorithm and the general logic behind it
-suggest that this is an oversight and that in the context of the
-for-loop n should be the number of full 32-bit quantities in b (rounded
-upwards). If w is 64, the current algorithm throws away half of all bits
-in b. If w is 16, the current algorithm sets half of all elements in v
-to 0.
-
      
-
-
      
-There are two more minor issues:
+After n2369 we have a single push_back overload in the sequence containers,
+of the "emplace" type. At variance with that, still in n2461, we have
+two separate overloads, the C++03 one + one taking an rvalue reference
+in the container adaptors. Therefore, simply from a consistency point of
+view, I was wondering whether the container adaptors should be aligned
+with the specifications of the sequence container themselves: thus have
+a single push along the lines:
 
      
 
-
        
-
      • 
-Strictly speaking end - begin is not defined since
-InputIterator is not required to be a random access iterator.
-
        • 
-
      • 
-Currently all integral types are allowed as input to the seed_seq
-constructor, including bool. IMHO allowing bools unnecessarily
-complicates the implementation without any real benefit to the user.
-I'd suggest to exclude bools as input.
-
        • 
-
      
+
      template<typename... _Args>
+void
+push(_Args&&... __args)
+  { c.push_back(std::forward<_Args>(__args)...); }
+
      
 
 
      [
-Bellevue:
+Related to 767
 ]
      
 
 
-
      
-Move to OPEN Bill will try to propose a resolution by the next meeting.
-
      
-
-
      [
-post Bellevue:  Bill provided wording.
-]
      
-
 
+
      Proposed resolution:
      
 
      
-This issue is made moot if 803 is accepted.
+Change 23.3.5.1.1 [queue.defn]:
 
      
 
-
-
-
      Proposed resolution:
      
+
      void push(const value_type& x) { c.push_back(x); }
+void push(value_type&& x) { c.push_back(std::move(x)); }
+template<class... Args> void push(Args&&... args) { c.push_back(std::forward<Args>(args)...); }
+
      
+
 
      
-Replace 26.5.7.1 [rand.util.seedseq] paragraph 6 with:
+Change 23.3.5.2 [priority.queue]:
+
      
+
+
      void push(const value_type& x) { c.push_back(x); }
+void push(value_type&& x) { c.push_back(std::move(x)); }
+template<class... Args> void push(Args&&... args) { c.push_back(std::forward<Args>(args)...); }
+
      
+
+
      
+Change 23.3.5.2.2 [priqueue.members]:
 
      
 
 
      
+
      void push(const value_type& x);
+
      
+
      
 
      
-Effects: Constructs a seed_seq object by effectively concatenating the
-low-order u bits of each of the elements of the supplied sequence [begin,
-end)
-in ascending order of significance to make a (possibly very large) unsigned
-binary number b having a total of n bits, and then carrying out the
-following
-algorithm:
+Effects:
 
      
+
      c.push_back(x);
+push_heap(c.begin(), c.end(), comp);
+
      
+
      
 
-
      for( v.clear(); n > 0; n -= 32 )
-   v.push_back(b mod 232), b /= 232;
+
      template<class... Args> void push(value_type Args&&... x args);
+
      
+
      
+
      
+Effects:
+
      
+
      c.push_back(std::moveforward<Args>(x args)...);
+push_heap(c.begin(), c.end(), comp);
 
      
 
      
+
      
+
+
      
+Change 23.3.5.3.1 [stack.defn]:
+
      
+
+
      void push(const value_type& x) { c.push_back(x); }
+void push(value_type&& x) { c.push_back(std::move(x)); }
+template<class... Args> void push(Args&&... args) { c.push_back(std::forward<Args>(args)...); }
+
      
+
 
 
 
      Rationale:
      
+
      
 Addressed by
-N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
+N2680 Proposed Wording for Placement Insert (Revision 1).
+
      
 
 
 
 
 
 
      
-
      802. knuth_b returns wrong value
      
-
      Section: 26.5.5 [rand.predef] Status: NAD
- Submitter: P.J. Plauger Opened: 2008-02-20  Last modified: 2008-03-17
      
-
      View all other issues in [rand.predef].
      
-
      View all issues with NAD status.
      
+
      757. Typo in the synopsis of vector
      
+
      Section: 23.3.6 [vector] Status: NAD Editorial
+ Submitter: Paolo Carlini Opened: 2007-11-04  Last modified: 2008-07-02
      
+
      View other active issues in [vector].
      
+
      View all other issues in [vector].
      
+
      View all issues with NAD Editorial status.
      
 
      Discussion:
      
 
      
-The 10,000th value returned by knuth_b is supposed to be
-1112339016. We get 2126698284.
+In the synopsis 23.3.6 [vector], there is the signature:
 
      
 
+
      void insert(const_iterator position, size_type n, T&& x);
+
      
 
-
      Proposed resolution:
      
 
      
-Change 26.5.5 [rand.predef]/p8:
+instead of:
 
      
 
-
      
-
      typedef shuffle_order_engine<minstd_rand0, 256> 
-        knuth_b; 
-
      
-
      
-Required behavior: The 10000th consecutive invocation of a default-constructed
-object of type knuth_b shall produce the value
-1112339016 2126698284.
-
      
-
      
+
      iterator insert(const_iterator position, T&& x);
+
      
+
+
      
+23.3.6.4 [vector.modifiers] is fine.
+
      
 
 
-
      [
-Bellevue: Submitter withdraws defect. "We got the wrong value for entirely the right reasons". NAD.
-]
      
+
+
      Proposed resolution:
      
+
      
+Change the synopsis in 23.3.6 [vector]:
+
      
+
+
      iterator insert(const_iterator position, const T& x); 
+iterator insert(const_iterator position, T&& x);
+void     insert(const_iterator position, size_type n, const T& x); 
+void     insert(const_iterator position, size_type n, T&& x);
+
      
 
 
 
 
 
 
      
-
      803. Simplification of seed_seq::seq_seq
      
-
      Section: 26.5.7.1 [rand.util.seedseq] Status: NAD Editorial
- Submitter: Charles Karney Opened: 2008-02-22  Last modified: 2009-03-09
      
-
      View all other issues in [rand.util.seedseq].
      
-
      View all issues with NAD Editorial status.
      
+
      760. The emplace issue
      
+
      Section: 23.2 [container.requirements] Status: NAD Future
+ Submitter: Paolo Carlini Opened: 2007-11-11  Last modified: 2009-07-17
      
+
      View other active issues in [container.requirements].
      
+
      View all other issues in [container.requirements].
      
+
      View all issues with NAD Future status.
      
 
      Discussion:
      
 
      
-seed_seq(InputIterator begin, InputIterator end); constructs a seed_seq
-object repacking the bits of supplied sequence [begin, end) into a
-32-bit vector.
+In an emplace member function the function parameter pack may be bound
+to a priori unlimited number of objects: some or all of them can be
+elements of the container itself. Apparently, in order to conform to the
+blanket statement 23.2 [container.requirements]/11, the
+implementation must check all of them for that possibility. A possible
+solution can involve extending the exception in 23.2 [container.requirements]/12 also to the emplace member. As a
+side note, the push_back and push_front member
+functions are luckily not affected by this problem, can be efficiently
+implemented anyway
 
      
+
+
      [
+Related to 767
+]
      
+
+
+
      [
+Bellevue:
+]
      
+
+
+
      
 
      
-This repacking triggers several problems:
+The proposed addition (13) is partially redundant with the existing
+paragraph 12. Why was the qualifier "rvalues" added to paragraph 12? Why
+does it not cover subelements and pointers?
 
      
-
        
-
      1. 
-Distinctness of the output of seed_seq::generate required the
-introduction of the initial "if (w < 32) v.push_back(n);"  (Otherwise
-the unsigned short vectors [1, 0] and [1] generate the same sequence.)
-
        2. 
-
      2. 
-Portability demanded the introduction of the template parameter u.
-(Otherwise some sequences could not be obtained on computers where no
-integer types are exactly 32-bits wide.)
-
        3. 
-
      3. 
-The description and algorithm have become unduly complicated.
-
        4. 
-
      
 
      
-I propose simplifying this seed_seq constructor to be "32-bit only".
-Despite it's being simpler, there is NO loss of functionality (see
-below).
+Resolution: Alan Talbot to rework language, then set state to Review.
 
      
+
      
+
+
      [
+2009-07 Frankfurt
+]
      
+
+
+
      
 
      
-Here's how the description would read
+The problem is broader than emplace. The LWG doesn't
+feel that it knows how to write wording that prohibits all of the
+problematic use cases at this time.
 
      
-
      
 
      
-26.5.7.1 [rand.util.seedseq] Class seed_seq
+NAD Future.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Add after 23.2 [container.requirements]/12:
 
      
 
-
      
-
      template<class InputIterator>
-  seed_seq(InputIterator begin, InputIterator end);
-
      
 
      
 
      
-5 Requires: NO CHANGE
+-12- Objects passed to member functions of a container as rvalue
+references shall not be elements of that container. No diagnostic
+required.
 
      
 
      
-6 Effects: Constructs a seed_seq object by
+
+-13- Objects bound to the function parameter pack of the
+emplace member function shall not be elements or sub-objects of
+elements of the container. No diagnostic required.
+
 
      
-
      
-
      for (InputIterator s = begin; s != end; ++s)
-   v.push_back((*s) mod 2^32);
-
      
-
      
-
      
-
      
+
 
      
 
+
+
+
+
+
+
      
+
      763. Renaming emplace() overloads
      
+
      Section: 23.2.4 [associative.reqmts] Status: NAD
+ Submitter: Sylvain Pion Opened: 2007-12-04  Last modified: 2008-03-12
      
+
      View all other issues in [associative.reqmts].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
 
      
-Discussion:
+The associative containers provide 2 overloads of emplace():
 
      
+
+
      template <class... Args> pair<iterator, bool> emplace(Args&&... args);
+template <class... Args> iterator emplace(const_iterator position, Args&&... args);
+
      
+
 
      
-The chief virtues here are simplicity, portability, and generality.
+This is a problem if you mean the first overload while passing
+a const_iterator as first argument.
 
      
-
        
-
      • 
-Simplicity -- compare the above specification with the
-n2461 proposal.
-
        • 
-
      • 
-Portability -- with iterator_traits<InputIterator>::value_type =
-uint_least32_t the user is guaranteed to get the same behavior across
-platforms.
-
        • 
-
      • 
-Generality -- any behavior that the
-n2461
-proposal can achieve can be
-obtained with this simpler proposal (albeit with a shuffling of bits
-in the input sequence).
-
        • 
-
      
+
+
      [
+Related to 767
+]
      
+
+
+
      [
+Bellevue:
+]
      
+
+
+
      
+
      
 
      
-Arguments (and counter-arguments) against making this change (and
-retaining the
-n2461
-behavior) are:
+This can be disambiguated by passing "begin" as the first argument in
+the case when the non-default choice is desired. We believe that desire
+will be rare.
 
      
-
        
-
      • 
 
        
-The user can pass an array of unsigned char and seed_seq will nicely
- repack it.
+Resolution: Change state to NAD.
 
        
+
+
+
        Proposed resolution:
        
 
        
- Response: So what?  Consider the seed string "ABC".  The
- n2461
- proposal results in
+Rename one of the two overloads.
+For example to emplace_here, hint_emplace...
 
        
-
        v = { 0x3, 0x434241 };
-
        
-
        
-while the simplified proposal yields
-
        
-
        v = { 0x41, 0x42, 0x43 };
-
        
-
        
-The results produced by seed_seq::generate with the two inputs are
-different but nevertheless equivalently "mixed up" and this remains
-true even if the seed string is long.
-
        
-
        • 
-
      • 
-
        
-With long strings (e.g., with bit-length comparable to the number of
- bits in the state), v is longer (by a factor of 4) with the simplified
- proposal and seed_seq::generate will be slower.
-
        
-
        
-Response: It's unlikely that the efficiency of seed_seq::generate will
- be a big issue.  If it is, the user is free to repack the seed vector
- before constructing seed_seq.
-
        
-
        • 
-
      • 
+
+
+
+
+
+
        
+
        764. equal_range on unordered containers should return a pair of local_iterators
        
+
        Section: 23.2.5 [unord.req] Status: NAD
+ Submitter: Joe Gottman Opened: 2007-11-29  Last modified: 2008-03-12
        
+
        View other active issues in [unord.req].
        
+
        View all other issues in [unord.req].
        
+
        View all issues with NAD status.
        
+
        Discussion:
        
 
        
-A user can pass an array of 64-bit integers and all the bits will be
- used.
+    A major attribute of the unordered containers is that iterating 
+though them inside a bucket is very fast while iterating between buckets 
+can be much slower.  If an unordered container has a low load factor, 
+iterating between the last iterator in one bucket and the next iterator, 
+which is in another bucket, is O(bucket_count()) which may be much 
+larger than O(size()).
 
        
 
        
- Response: Indeed.  However, there are many instances in the 
- n2461
- where integers are silently coerced to a narrower width and this
- should just be a case of the user needing to read the documentation.
- The user can of course get equivalent behavior by repacking his seed
- into 32-bit pieces.  Furthermore, the unportability of the 
- n2461
- proposal with
+    If b is an non-const unordered container of type B and k is an 
+object of it's key_type, then b.equal_range(k) currently returns 
+pair<B::iterator, B::iterator>. Consider the following code:
 
        
-
        unsigned long s[] = {1, 2, 3, 4};
-seed_seq q(s, s+4);
+
+
        B::iterator lb, ub;
+tie(lb, ub) = b.equal_range(k);
+for (B::iterator it = lb; it != ub; ++it) {
+        // Do something with *it
+}
 
        
+
 
        
- which typically results in v = {1, 2, 3, 4} on 32-bit machines and in
-v = {1, 0, 2, 0, 3, 0, 4, 0} on 64-bit machines is a major pitfall for
- unsuspecting users.
+If b.equal_range(k) returns a non-empty range (i.e. b contains at least 
+on element whose key is equivalent to k), then every iterator in the 
+half-open range [lb, ub) will be in the same bucket, but ub will likely 
+either be in a different bucket or be equal to b.end().  In either case, 
+iterating between ub - 1 and ub could take a much longer time than 
+iterating through the rest of the range.
 
        
-
        • 
-
      
-
 
      
-Note: this proposal renders moot issues 782 and 800.
+If instead of returning pair<iterator, iterator>, equal_range were to 
+return pair<local_iterator, local_iterator>, then ub (which, like lb, 
+would now be a local_iterator) could be guaranteed to always be in the 
+same bucket as lb. In the cases where currently ub is equal to b.end()
+or is in a different bucket, ub would be equal to b.end(b.bucket(key)). 
+  This would make iterating between lb and ub much faster, as every 
+iteration would be constant time.
 
      
 
 
      [
@@ -16125,100 +17287,88 @@ Bellevue:
 
 
 
      
-Walter needs to ask Fermilab for guidance. Defer till tomorrow. Bill likes the proposed resolution.
+The proposed resolution breaks consistency with other container types
+for dubious benefit, and iterators are already constant time.
 
      
 
-
      [
-Sophia Antipolis:
-]
      
 
 
-
      
-
      
-Marc Paterno wants portable behavior between 32bit and 64bit machines;
-we've gone to significant trouble to support portability of engines and
-their values.
-
      
-
      
-Jens: the new algorithm looks perfectly portable
-
      
-
      
-Marc Paterno to review off-line.
-
      
-
      
-Modify the proposed resolution to read "Constructs a seed_seq object by the following algorithm ..."
-
      
-
      
-Disposition: move to review; unanimous consent.
-
      
+
      Proposed resolution:
      
 
      
-(moots 782 and 800)
+Change the entry for equal_range in Table 93 (23.2.5 [unord.req]) as follows:
 
      
-
      
+
+
+
+
+
+
+
+
+
+
+
+
      expression return type assertion/note pre/post-condition complexity
      b.equal_range(k)pair<local_iterator,local_iterator>; pair<const_local_iterator,const_local_iterator> for const b.Returns a range containing all elements with keys equivalent to k. Returns make_pair(b.end(b.bucket(key)),b.end(b.bucket(key))) if no such elements exist.Average case Θ(b.count(k)). Worst case Θ(b.size()). 
      
 
 
 
-
      Proposed resolution:
      
+
+
+
      
+
      767. Forwarding and backward compatibility
      
+
      Section: 23 [containers] Status: NAD Editorial
+ Submitter: Sylvain Pion Opened: 2007-12-28  Last modified: 2008-06-18
      
+
      View other active issues in [containers].
      
+
      View all other issues in [containers].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
 
      
-Change 26.5.7.1 [rand.util.seedseq]:
+Playing with g++'s C++0X mode, I noticed that the following
+code, which used to compile:
 
      
 
-
      
-
      template<class InputIterator, 
-  size_t u = numeric_limits<iterator_traits<InputIterator>::value_type>::digits>
-  seed_seq(InputIterator begin, InputIterator end);
-
      
-
      
+
      #include <vector>
+
+int main()
+{
+    std::vector<char *> v;
+    v.push_back(0);
+}
+
      
+
 
      
--5- Requires: InputIterator shall satisfy the requirements of an input iterator (24.1.1)
-such that iterator_traits<InputIterator>::value_type shall denote an integral type.
+now fails with the following error message:
 
      
+
+
      .../include/c++/4.3.0/ext/new_allocator.h: In member
+function 'void __gnu_cxx::new_allocator<_Tp>::construct(_Tp*,
+_Args&& ...) [with _Args = int, _Tp = char*]':
+.../include/c++/4.3.0/bits/stl_vector.h:707: instantiated from 'void
+std::vector<_Tp, _Alloc>::push_back(_Args&& ...) [with
+_Args = int, _Tp = char*, _Alloc = std::allocator<char*>]'
+test.cpp:6: instantiated from here
+.../include/c++/4.3.0/ext/new_allocator.h:114: error: invalid
+conversion from 'int' to 'char*'
+
      
+
 
      
--6- Constructs a seed_seq object by the following algorithm rearranging some or all of the bits of the supplied sequence
-[begin,end) of w-bit quantities into 32-bit units, as if by the following: 
+As far as I know, g++ follows the current draft here.
 
      
 
      
-First extract the rightmost u bits from each of the n = end
-- begin elements of the supplied sequence and concatenate all the
-extracted bits to initialize a single (possibly very large) unsigned
-binary number, b = ∑n-1i=0 (begin[i] 
-mod 2u) · 2w·i (in which the bits of each begin[i]
-are treated as denoting an unsigned quantity). Then carry out 
-the following algorithm:
+Does the committee really intend to break compatibility for such cases?
 
      
-
      
-v.clear(); 
-if ($w$ < 32) 
-  v.push_back($n$); 
-for( ; $n$ > 0; --$n$) 
-  v.push_back(b mod 232), b /= 232;
-
      
-
      
-
      
-for (InputIterator s = begin; s != end; ++s)
-   v.push_back((*s) mod 232);
-
      
-
      
-
      
-
      
-
-
-
      Rationale:
      
-Addressed by
-N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
-
 
+
      [
+Sylvain adds: 
+]
      
 
 
+
      
+
      
+I just noticed that std::pair has the same issue.
+The following now fails with GCC's -std=c++0x mode:
+
      
 
-
      
-
      811. pair of pointers no longer works with literal 0
      
-
      Section: 20.3.3 [pairs] Status: NAD Editorial
- Submitter: Doug Gregor Opened: 2008-03-14  Last modified: 2008-09-26
      
-
      View other active issues in [pairs].
      
-
      View all other issues in [pairs].
      
-
      View all issues with NAD Editorial status.
      
-
      Discussion:
      
 
      #include <utility>
 
 int main()
@@ -16228,45 +17378,43 @@ int main()
 
      
 
 
      
-I just got a bug report about that, because it's valid C++03, but not
-C++0x. The important realization, for me, is that the emplace
-proposal---which made push_back variadic, causing the push_back(0)
-issue---didn't cause this break in backward compatibility. The break
-actually happened when we added this pair constructor as part of adding
-rvalue references into the language, long before variadic templates or
-emplace came along:
+I have not made any general audit for such problems elsewhere.
 
      
+
      
 
-
      template<class U, class V> pair(U&& x, V&& y);
-
      
-
-
      
-Now, concepts will address this issue by constraining that pair
-constructor to only U's and V's that can properly construct "first" and
-"second", e.g. (from
-N2322):
-
      
+
      [
+Related to 756
+]
      
 
-
      template<class U , class V >
-requires Constructible<T1, U&&> && Constructible<T2, V&&>
-pair(U&& x , V&& y );
-
      
 
 
      [
-San Francisco:
+Bellevue:
 ]
      
 
 
 
      
 
      
-Suggested to resolve using pass-by-value for that case.
+Motivation is to handle the old-style int-zero-valued NULL pointers.
+Problem: this solution requires concepts in some cases, which some users
+will be slow to adopt. Some discussion of alternatives involving
+prohibiting variadic forms and additional library-implementation
+complexity.
+
      
+
      
+Discussion of "perfect world" solutions, the only such solution put
+forward being to retroactively prohibit use of the integer zero for a
+NULL pointer. This approach was deemed unacceptable given the large
+bodies of pre-existing code that do use integer zero for a NULL pointer.
 
      
 
      
-Side question: Should pair interoperate with tuples? Can construct a
-tuple of a pair, but not a pair from a two-element tuple.
+Another approach is to change the member names. Yet another approach is
+to forbid the extension in absence of concepts.
 
      
 
      
-Related to 885.
+Resolution: These issues (756, 767, 760, 763) will be subsumed into a
+paper to be produced by Alan Talbot in time for review at the 2008
+meeting in France. Once this paper is produced, these issues will be
+moved to NAD.
 
      
 
      
 
@@ -16274,121 +17422,201 @@ Related to 
 
-
-
      Rationale:
      
-
      [
-San Francisco:
-]
      
-
-
 
      
-Solved by
-N2770.
-
      
-
-
+
+
+
+
 
+
+
+
+
+
+
 
+
+
+
+
+
+
 
+
+
+
+
+
+
 
+
+
+
+
+
+
+
+
      expression return type assertion/note
      pre-/post-condition      		 container
      
+a.push_front(t)
+
+void
+
+a.insert(a.begin(), t)
      
+Requires: T shall be CopyConstructible.
+      		
+list, deque
+
      
+a.push_front(rv)
+
+void
+
+a.insert(a.begin(), rv)
      
+Requires: T shall be MoveConstructible.
+      		
+list, deque
+
      
+a.push_back(t)
+
+void
+
+a.insert(a.end(), t)
      
+Requires: T shall be CopyConstructible.
+      		
+list, deque, vector, basic_string
+
      
+a.push_back(rv)
+
+void
+
+a.insert(a.end(), rv)
      
+Requires: T shall be MoveConstructible.
+      		
+list, deque, vector, basic_string
+
      
+
      
 
-
      
-
      812. unsolicited multithreading considered harmful?
      
-
      Section: 25.5.1 [alg.sort] Status: NAD Editorial
- Submitter: Paul McKenney Opened: 2008-02-27  Last modified: 2008-09-17
      
-
      View all issues with NAD Editorial status.
      
-
      Discussion:
      
 
      
-Multi-threading is a good thing, but unsolicited multi-threading can
-potentially be harmful.  For example, sort() performance might be
-greatly increased via a multithreaded implementation.  However, such
-a multithreaded implementation could result in concurrent invocations
-of the user-supplied comparator.  This would in turn result in problems
-given a caching comparator that might be written for complex sort keys.
-Please note that this is not a theoretical issue, as multithreaded
-implementations of sort() already exist.
+Change the synopsis in 23.3.2 [deque]:
 
      
+
+
      void push_front(const T& x);
+void push_front(T&& x);
+void push_back(const T& x);
+void push_back(T&& x);
+template <class... Args> requires Constructible<T, Args&&...> void push_front(Args&&... args);
+template <class... Args> requires Constructible<T, Args&&...> void push_back(Args&&... args);
+
      
+
 
      
-Having a multithreaded sort() available is good, but it should not
-be the default for programs that are not explicitly multithreaded.
-Users should not be forced to deal with concurrency unless they have
-asked for it.
+Change 23.3.2.3 [deque.modifiers]:
 
      
 
-
      [
-This may be covered by
-N2410
-Thread-Safety in the Standard Library (Rev 1).
-]
      
+
      void push_front(const T& x);
+void push_front(T&& x);
+void push_back(const T& x);
+void push_back(T&& x);
+template <class... Args> requires Constructible<T, Args&&...> void push_front(Args&&... args);
+template <class... Args> requires Constructible<T, Args&&...> void push_back(Args&&... args);
+
      
 
+
      
+Change the synopsis in 23.3.4 [list]:
+
      
 
+
      void push_front(const T& x);
+void push_front(T&& x);
+void push_back(const T& x);
+void push_back(T&& x);
+template <class... Args> requires Constructible<T, Args&&...> void push_front(Args&&... args);
+template <class... Args> requires Constructible<T, Args&&...> void push_back(Args&&... args);
+
      
 
-
      Proposed resolution:
      
 
      
+Change 23.3.4.3 [list.modifiers]:
 
      
 
+
      void push_front(const T& x);
+void push_front(T&& x);
+void push_back(const T& x);
+void push_back(T&& x);
+template <class... Args> requires Constructible<T, Args&&...> void push_front(Args&&... args);
+template <class... Args> requires Constructible<T, Args&&...> void push_back(Args&&... args);
+
      
 
-
      Rationale:
      
-This is already covered by 17.6.5.6/20 in N2723.
+
      
+Change the synopsis in 23.3.6 [vector]:
+
      
 
+
      void push_back(const T& x);
+void push_back(T&& x);
+template <class... Args> requires Constructible<T, Args&&...> void push_back(Args&&... args);
+
      
 
+
      
+Change 23.3.6.4 [vector.modifiers]:
+
      
 
+
      void push_back(const T& x);
+void push_back(T&& x);
+template <class... Args> requires Constructible<T, Args&&...> void push_back(Args&&... args);
+
      
 
 
-
      
-
      826. Equivalent of %'d, or rather, lack thereof?
      
-
      Section: 22.4.2.2 [locale.nm.put] Status: NAD
- Submitter: Peter Dimov Opened: 2008-04-07  Last modified: 2008-06-18
      
-
      View all issues with NAD status.
      
-
      Discussion:
      
+
+
+
      Rationale:
      
 
      
-In the spirit of printf vs iostream...
+Addressed by
+N2680 Proposed Wording for Placement Insert (Revision 1).
 
      
 
 
      
-POSIX printf says that %'d should insert grouping characters (and the
-implication is that in the absence of ' no grouping characters are
-inserted). The num_put facet, on the other hand, seems to always insert
-grouping characters. Can this be considered a defect worth fixing for
-C++0x? Maybe ios_base needs an additional flag?
+If there is still an issue with pair, Howard should submit another issue.
 
      
 
-
      [
-Pablo Halpern:
-]
      
 
 
-
      
-I'm not sure it constitutes a defect, but I would be in favor of adding
-another flag (and corresponding manipulator).
-
      
 
-
      [
-Martin Sebor:
-]
      
 
+
      
+
      773. issues with random
      
+
      Section: 26.5.8.1 [rand.dist.uni] Status: NAD
+ Submitter: P.J. Plauger Opened: 2008-01-14  Last modified: 2008-02-27
      
+
      View all other issues in [rand.dist.uni].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
        
+
      1. 
+26.5.8.1.1 [rand.dist.uni.int] uniform_int constructor has changed the default
+max constructor parameter from 9 (in TR1) to max(). The value
+is arbitrary at best and shouldn't be lightly changed because
+it breaks backward compatibility.
+
        2. 
 
-
        
-I don't know if it qualifies as a defect but I agree that there
-should be an easy way to control whether the thousands separator
-should or shouldn't be inserted. A new flag would be in line with
-the current design of iostreams (like boolalpha, showpos, or
-showbase).
-
        
+
      2. 
+26.5.8.1.1 [rand.dist.uni.int] uniform_int has a parameter param that you can
+provide on construction or operator(), set, and get. But there
+is not even a hint of what this might be for.
+
        3. 
+
+
      3. 
+26.5.8.1.2 [rand.dist.uni.real] uniform_real. Same issue as #2.
+
        4. 
+
      
 
 
      [
-Sophia Antipolis:
+Bellevue:
 ]
      
 
 
 
      
-This is not a part of C99. LWG suggests submitting a paper may be appropriate.
+NAD. Withdrawn.
 
      
 
 
-
 
      Proposed resolution:
      
 
      
 
      
@@ -16398,1737 +17626,10340 @@ This is not a part of C99. LWG suggests submitting a paper may be appropriate.
 
 
 
      
-
      831. wrong type for not_eof()
      
-
      Section: 21.2.3 [char.traits.specializations] Status: NAD Editorial
- Submitter: Dietmar Kühl Opened: 2008-04-23  Last modified: 2008-06-19
      
-
      View all other issues in [char.traits.specializations].
      
-
      View all issues with NAD Editorial status.
      
+
      784. unique_lock::release
      
+
      Section: 30.4.3.2.3 [thread.lock.unique.mod] Status: NAD
+ Submitter: Constantine Sapuntzakis Opened: 2008-02-02  Last modified: 2008-02-27
      
+
      View all issues with NAD status.
      
 
      Discussion:
      
 
      
-  In Table 56 (Traits requirements) the not_eof() member function
-  is using an argument of type e which denotes an object of
-  type X::int_type. However, the specializations in
-  21.2.3 [char.traits.specializations] all use char_type.
-  This would effectively mean that the argument type actually can't
-  represent EOF in the first place. I'm pretty sure that the type used
-  to be int_type which is quite obviously the only sensible
-  argument.
+unique_lock::release will probably lead to many mistakes where people
+call release instead of unlock. I just coded such a mistake using the
+boost pre-1.35 threads library last week.
 
      
+
 
      
-  This issue is close to being editorial. I suspect that the proposal
-  changing this section to include the specializations for char16_t
-  and char32_t accidentally used the wrong type.
+In many threading libraries, a call with release in it unlocks the
+lock (e.g. ReleaseMutex in Win32, java.util.concurrent.Semaphore).
 
      
 
-
-
      Proposed resolution:
      
 
      
-  In 21.2.3.1 [char.traits.specializations.char],
-  21.2.3.2 [char.traits.specializations.char16_t],
-  21.2.3.3 [char.traits.specializations.char32_t], and
-   [char.traits.specializations.wchar_t] correct the
-  argument type from char_type to int_type.
+I don't call unique_lock::lock much at all, so I don't get to see the
+symmetry between ::lock and ::unlock. I usually use the constructor to
+lock the mutex. So I'm left to remember whether to call release or
+unlock during the few times I need to release the mutex before the scope
+ends. If I get it wrong, the compiler doesn't warn me.
 
      
 
+
      
+An alternative name for release may be disown.
+
      
 
-
      Rationale:
      
-Already fixed in WP.
-
-
+
      
+This might be a rare case where usability is hurt by consistency with
+the rest of the C++ standard (e.g. std::auto_ptr::release).
+
      
 
+
      [
+Bellevue:
+]
      
 
 
-
      
-
      832. Applying constexpr to System error support
      
-
      Section: 19.5 [syserr] Status: NAD
- Submitter: Beman Dawes Opened: 2008-05-14  Last modified: 2008-09-17
      
-
      View all other issues in [syserr].
      
-
      View all issues with NAD status.
      
-
      Discussion:
      
-
      
-Initialization of objects of class error_code
-(19.5.2 [syserr.errcode]) and class
-error_condition (19.5.3 [syserr.errcondition]) can be made simpler and more reliable by use of
-the new constexpr feature 
-[N2349]
-of C++0x. Less code will need to be
-generated for both library implementations and user programs when
-manipulating constant objects of these types. 
-
      
+
      
+Change a name from release to disown. However prior art uses the release
+name. Compatibility with prior art is more important that any possible
+benefit such a change might make. We do not see the benefit for
+changing. NAD
+
      
 
-
      
-This was not proposed originally because the constant expressions
-proposal was moving into the standard at about the same time as the
-Diagnostics Enhancements proposal 
-[N2241],
-and it wasn't desirable to
-make the later depend on the former. There were also technical concerns
-as to how constexpr would apply to references. Those concerns are now
-resolved; constexpr can't be used for references, and that fact is
-reflected in the proposed resolution.
-
      
 
+
      Proposed resolution:
      
 
      
-Thanks to Jens Maurer, Gabriel Dos Reis, and Bjarne Stroustrup for clarification of constexpr requirements.
+Change the synopsis in 30.4.3.2 [thread.lock.unique]:
 
      
 
+
      template <class Mutex> 
+class unique_lock 
+{ 
+public:
+   ...
+   mutex_type* release disown();
+   ...
+};
+
      
+
 
      
-LWG issue 804 is related in that it raises the question of whether the
-exposition only member cat_ of class error_code (19.5.2 [syserr.errcode]) and class
-error_condition (19.5.3 [syserr.errcondition]) should be presented as a reference or pointer.
-While in the context of 804 that is arguably an editorial question,
-presenting it as a pointer becomes more or less required with this
-proposal, given constexpr does not play well with references. The
-proposed resolution thus changes the private member to a pointer, which
-also brings it in sync with real implementations.
+Change 30.4.3.2.3 [thread.lock.unique.mod]:
 
      
 
-
      [
-Sophia Antipolis:
-]
      
+
      mutex_type *release disown();
+
      
 
 
-
      
-On going question of extern pointer vs. inline functions for interface.
-
      
 
-
      [
-Pre-San Francisco:
-]
      
 
 
-
      
-
      
-Beman Dawes reports that this proposal is unimplementable, and thus NAD.
-
      
+
      
+
      785. Random Number Requirements in TR1
      
+
      Section: TR1 5.1.4.5 [tr.rand.eng.disc], TR1 5.1.4.6 [tr.rand.eng.xor] Status: NAD
+ Submitter: John Maddock Opened: 2008-01-15  Last modified: 2009-07-13
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
 
      
-Implementation would require constexpr objects of classes derived
-from class error_category, which has virtual functions, and that is
-not allowed by the core language. This was determined when trying to
-implement the proposal using a constexpr enabled compiler provided
-by Gabriel Dos Reis, and subsequently verified in discussions with
-Gabriel and Jens Maurer.
+Table 16 of TR1 requires that all Pseudo Random Number generators have a
 
      
 
-
      
-
+
      seed(integer-type s)
+
      
 
-
      Proposed resolution:
      
 
      
-The proposed wording assumes the LWG 805 proposed wording has been
-applied to the WP, resulting in the former posix_category being renamed
-generic_category. If 805 has not been applied, the names in this
-proposal must be adjusted accordingly.
+member function that is equivalent to:
 
      
 
+
      mygen = Generator(s)
+
      
+
 
      
-Change 19.5.1.1 [syserr.errcat.overview] Class
-error_category overview error_category synopsis  as
-indicated:
+But the generators xor_combine and discard_block have no such seed member, only the
 
      
 
-
      const error_category& get_generic_category();
-const error_category& get_system_category();
-
-static extern const error_category&* const generic_category = get_generic_category();
-static extern const error_category&* const native_category system_category = get_system_category();
+
      template <class Gen>
+seed(Gen&);
 
      
 
 
      
-Change 19.5.1.5 [syserr.errcat.objects] Error category objects as indicated:
+member, which will not accept an integer literal as an argument: something that appears to violate the intent of Table 16.
 
      
 
-
      
-
      extern const error_category&* const get_generic_category();
-
      
 
      
-Returns: A reference generic_category shall point
-to an a statically initialized object of a type derived from
-class error_category.
+So... is this a bug in TR1?
 
      
 
-
      
-Remarks: The object's default_error_condition and equivalent virtual
-functions shall behave as specified for the class error_category. The
-object's name virtual function shall return a pointer to the string
-"GENERIC".
+
      This is a real issue BTW, since the Boost implementation does adhere
+to the requirements of Table 16, while at least one commercial
+implementation does not and follows a strict adherence to sections
+5.1.4.5 and 5.1.4.6 instead.
 
      
 
-
      extern const error_category&* const get_system_category();
-
      
-
-
      
-Returns: A reference system_category shall point
-to an a statically
-initialized object of a type derived from class error_category.
-
      
+
      [
+Jens adds:
+]
      
 
-
      
-Remarks:  The object's equivalent virtual functions shall behave as
-specified for class error_category. The object's name virtual function
-shall return a pointer to the string "system". The object's
-default_error_condition virtual function shall behave as follows:
-
      
 
-
      
-If the argument ev corresponds to a POSIX errno value posv, the function
-shall return error_condition(posv, generic_category). Otherwise, the
-function shall return error_condition(ev, system_category). What
-constitutes correspondence for any given operating system is
-unspecified. [Note: The number of potential system error codes is large
-and unbounded, and some may not correspond to any POSIX errno value.
-Thus implementations are given latitude in determining correspondence.
--- end note]
-
      
+
      
+Both engines do have the necessary
+constructor, therefore the omission of the seed() member
+functions appears to be an oversight.
 
      
 
-
      
-Change 19.5.2.2 [syserr.errcode.overview] Class error_code overview as indicated:
-
      
-
-
      class error_code {
-public:
-  ...;
-  constexpr error_code(int val, const error_category&* cat);
-  ...
-  void assign(int val, const error_category&* cat);
-  ...
-  const error_category&* category() const;
-  ...
-private:
-  int val_;                    // exposition only
-  const error_category&* cat_; // exposition only
-
      
+
      [
+Post Summit Daniel adds:
+]
      
 
-
      
-Change 19.5.2.3 [syserr.errcode.constructors] Class error_code constructors as indicated:
-
      
 
 
      
-
      constexpr error_code(int val, const error_category&* cat);
-
      
-
      
-Effects: Constructs an object of type error_code.
-
      
-
      
-Postconditions: val_ == val and cat_ == cat.
-
      
-
      
-Throws: Nothing.
-
      
+Recommend NAD: xor_combine does no longer exist and discard_block[_engine]
+has now the required seed overload accepting a result_type, which shall be an
+unsigned integral type.
 
      
 
-
      
-Change 19.5.2.4 [syserr.errcode.modifiers] Class error_code modifiers  as indicated:
-
      
+
      [
+Batavia (2009-05):
+]
      
 
 
      
-
      void assign(int val, const error_category&* cat);
-
      
-
      
-Postconditions: val_ == val and cat_ == cat.
-
      
-
      
-Throws: Nothing.
-
      
+Move to NAD as recommended.
 
      
 
+
+
      Proposed resolution:
      
 
      
-Change 19.5.2.5 [syserr.errcode.observers] Class error_code observers  as indicated:
+NAD Recommended.
 
      
 
-
      
-
      const error_category&* category() const;
-
      
 
+
+
+
+
      
+
      786. Thread library timed waits, UTC and monotonic clocks
      
+
      Section: 20.9 [time] Status: NAD Editorial
+ Submitter: Christopher Kohlhoff, Jeff Garland Opened: 2008-02-03  Last modified: 2008-09-30
      
+
      View all other issues in [time].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
 
      
-Returns: cat_.
+The draft C++0x thread library requires that the time points of type
+system_time and returned by get_system_time() represent Coordinated
+Universal Time (UTC) (section  [datetime.system]). This can lead to
+surprising behavior when a library user performs a duration-based wait,
+such as condition_variable::timed_wait(). A complete explanation of the
+problem may be found in the
+Rationale for the Monotonic Clock
+section in POSIX, but in summary:
 
      
+
+
        
+
      • 
+Operations such as condition_variable::timed_wait() (and its POSIX
+equivalent, pthread_cond_timedwait()) are specified using absolute times
+to address the problem of spurious wakeups.
+
        • 
+
+
      • 
+The typical use of the timed wait operations is to perform a relative
+wait. This may be achieved by first calculating an absolute time as the
+sum of the current time and the desired duration. In fact, the C++0x
+thread library includes duration-based overloads of
+condition_variable::timed_wait() that behave as if by calling the
+corresponding absolute time overload with a time point value of
+get_system_time() + rel_time.
+
        • 
+
+
      • 
+A UTC clock may be affected by changes to the system time, such as
+synchronization with an external source, leap seconds, or manual changes
+to the clock.
+
        • 
+
+
      • 
+Should the clock change during a timed wait operation, the actual
+duration of the wait will not be the expected length. For example, a
+user may intend a timed wait of one second duration but, due to an
+adjustment of the system clock backwards by a minute, the wait instead
+takes 61 seconds.
+
        • 
+
      
+
 
      
-Throws: Nothing.
+POSIX solves the problem by introducing a new monotonic clock, which is
+unaffected by changes to the system time. When a condition variable is
+initialized, the user may specify whether the monotonic clock is to be
+used. (It is worth noting that on POSIX systems it is not possible to
+use condition_variable::native_handle() to access this facility, since
+the desired clock type must be specified during construction of the
+condition variable object.)
 
      
-
      
 
 
      
-Change 19.5.3.2 [syserr.errcondition.overview] Class error_condition overview   as indicated:
+In the context of the C++0x thread library, there are added dimensions
+to the problem due to the need to support platforms other than POSIX:
 
      
 
-
      
-
      class error_condition {
-public:
-  ...;
-  constexpr error_condition(int val, const error_category&* cat);
-  ...
-  void assign(int val, const error_category&* cat);
-  ...
-  const error_category&* category() const;
-  ...
-private:
-  int val_;                    // exposition only
-  const error_category&* cat_; // exposition only
-
      
-
      
+
        
+
      • 
+Some environments (such as embedded systems) do not have a UTC clock, but do have a monotonic clock.
+
        • 
 
-
        
-Change 19.5.3.3 [syserr.errcondition.constructors] Class error_condition constructors as indicated:
-
        
+
      • 
+Some environments do not have a monotonic clock, but do have a UTC clock.
+
        • 
 
-
        
-
        constexpr error_condition(int val, const error_category&* cat);
-
        
-
        
-Effects: Constructs an object of type error_condition.
-
        
-
        
-Postconditions: val_ == val and cat_ == cat.
-
        
-
        
-Throws: Nothing.
-
        
-
        
+
      • 
+The Microsoft Windows API's synchronization functions use relative
+timeouts based on an implied monotonic clock. A program that switches
+from the Windows API to the C++0x thread library will now find itself
+susceptible to clock changes.
+
        • 
+
      
 
 
      
-Change 19.5.3.4 [syserr.errcondition.modifiers] Class error_condition modifiers as indicated:
+One possible minimal solution:
 
      
 
-
      
-
      void assign(int val, const error_category&* cat);
-
      
-
      
-Postconditions: val_ == val and cat_ == cat.
-
      
-
      
-Throws: Nothing.
-
      
-
      
+
        
+
      • 
+Strike normative references to UTC and an epoch based on 1970-01-01.
+
        • 
 
-
        
-Change 19.5.3.5 [syserr.errcondition.observers] Class error_condition observers as indicated:
-
        
+
      • 
+Make the semantics of system_time and get_system_time()
+implementation-defined (i.e standard library implementors may choose the
+appropriate underlying clock based on the capabilities of the target
+platform).
+
        • 
 
-
        
-
        const error_category&* category() const;
-
        
-
        
-Returns: cat_.
-
        
-
        
-Throws: Nothing.
-
        
-
        
+
      • 
+Add a non-normative note encouraging use of a monotonic clock.
+
        • 
 
-
        
-Throughout 19.5 [syserr] System error support, change "category()."  to "category()->".
-Appears approximately six times.
-
        
+
      • 
+Remove system_time::seconds_since_epoch().
+
        • 
 
-
        
-[Partially Editorial] In 19.5.4 [syserr.compare] Comparison operators,
-paragraphs 2 and 4, change "category.equivalent("  to
-"category()->equivalent(".
-
        
+
      • 
+Change the constructor explicit system_time(time_t secs, nanoseconds ns
+= 0) to explicit system_time(nanoseconds ns).
+
        • 
+
      
 
-
      
-Change 19.5.5.1 [syserr.syserr.overview] Class system_error overview as indicated:
-
      
 
-
      public:
-  system_error(error_code ec, const string& what_arg);
-  system_error(error_code ec);
-  system_error(int ev, const error_category&* ecat,
-      const string& what_arg);
-  system_error(int ev, const error_category&* ecat);
-
      
 
+
      Proposed resolution:
      
 
      
-Change 19.5.5.2 [syserr.syserr.members] Class system_error members as indicated:
 
      
 
-
      
-
      system_error(int ev, const error_category&* ecat, const string& what_arg);
-
      
-
      
-
      
-Effects: Constructs an object of class system_error.
-
      
-
      
-Postconditions: code() == error_code(ev, ecat) and
-strcmp(runtime_error::what(), what_arg.c_str()) == 0.
-
      
-
      
 
-
      system_error(int ev, const error_category&* ecat);
-
      
-
      
-
      
-Effects: Constructs an object of class system_error.
-
      
-
      
-Postconditions: code() == error_code(ev, ecat) and
-strcmp(runtime_error::what(), "") == 0.
-
      
-
      
-
      
+
      Rationale:
      
+Addressed by
+N2661: A Foundation to Sleep On.
 
 
 
-
      Rationale:
      
+
+
+
      
+
      790. xor_combine::seed not specified
      
+
      Section: X [rand.adapt.xor] Status: NAD
+ Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2008-02-27
      
+
      View all other issues in [rand.adapt.xor].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+xor_combine::seed(result_type) and seed(seed_seq&) don't say what
+happens to each of the sub-engine seeds. (Should probably do the same
+to both, unlike TR1.)
+
      
+
 
      [
-San Francisco:
+Bellevue:
 ]
      
 
 
 
      
-NAD because Beman said so.
+Overcome by the previous proposal. NAD mooted by resolution of 789.
 
      
 
 
 
+
      Proposed resolution:
      
+
+
+
 
 
 
      
-
      840. pair default template argument
      
-
      Section: 20.3.3 [pairs] Status: NAD
- Submitter: Thorsten Ottosen Opened: 2008-05-23  Last modified: 2008-06-18
      
-
      View other active issues in [pairs].
      
-
      View all other issues in [pairs].
      
+
      791. piecewise_constant_distribution::densities has wrong name
      
+
      Section: 26.5.8.5.2 [rand.dist.samp.pconst] Status: NAD
+ Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2008-03-11
      
+
      View all other issues in [rand.dist.samp.pconst].
      
 
      View all issues with NAD status.
      
 
      Discussion:
      
 
      
-I have one issue with std::pair. Well, it might just be a very annoying
-historical accident, but why is there no default template argument for
-the second template argument? This is so annoying when the type in
-question is looong and hard to write (type deduction with auto won't
-help those cases where we use it as a return or argument type).
+piecewise_constant_distribution::densities() should be probabilities(),
+just like discrete_distribution. (There's no real use for weights divided
+by areas.)
+
      
+
+
      [
+Bellevue:
+]
      
+
+
+
      
+
      
+Fermilab does not agree with this summary. As defined in the equation in
+26.4.8.5.2/4, the quantities are indeed probability densities not
+probabilities. Because we view this distribution as a parameterization
+of a *probability density function*, we prefer to work in terms of
+probability densities.
+
      
+
+
      
+We don't think this should be changed.
+
      
+
+
      
+If there is a technical argument about why the implementation dealing
+with these values can't be as efficient as one dealing with
+probabilities, we might reconsider. We don't care about this one member
+function being somewhat more or less efficient; we care about the size
+of the distribution object and the speed of the calls to generate
+variates.
 
      
+
      
+
 
 
 
      Proposed resolution:
      
+
 
      
-Change the synopsis in 20.3 [utility] to read:
+Change synopsis in 26.5.8.5.2 [rand.dist.samp.pconst]:
 
      
 
-
      template <class T1, class T2 = T1> struct pair;
+
      template <class RealType = double> 
+class piecewise_constant_distribution 
+{ 
+public:
+    ...
+    vector<double> densities probabilities() const;
+    ...
+};
 
      
 
 
      
-Change 20.3.3 [pairs] to read:
+Change 26.5.8.5.2 [rand.dist.samp.pconst]/6:
 
      
 
-
      namespace std {
- template <class T1, class T2 = T1>
- struct pair {
-   typedef T1 first_type;
-   typedef T2 second_type;
-   ...
+
      vector<double> densities probabilities() const;
 
      
 
 
-
      Rationale:
      
-std::pair is a heterogeneous container.
-
 
 
 
 
 
      
-
      841. cstdint.syn inconsistent with C99
      
-
      Section: 18.4.1 [cstdint.syn] Status: NAD Editorial
- Submitter: Martin Sebor Opened: 2008-05-17  Last modified: 2008-09-17
      
-
      View all other issues in [cstdint.syn].
      
+
      793. discrete_distribution missing constructor
      
+
      Section: 26.5.8.5.1 [rand.dist.samp.discrete] Status: NAD Editorial
+ Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2009-03-09
      
+
      View all other issues in [rand.dist.samp.discrete].
      
 
      View all issues with NAD Editorial status.
      
 
      Discussion:
      
-   
      
+
      
+discrete_distribution should have a constructor like:
+
      
 
-In specifying the names of macros and types defined in
-header <stdint.h>, C99 makes use of the
-symbol N to accommodate unusual platforms with
-word sizes that aren't powers of two. C99
-permits N to take on any positive integer value
-(including, for example, 24).
+
      template<class _Fn>
+  discrete_distribution(result_type _Count, double _Low, double _High,
+                        _Fn& _Func);
+
      
 
-   
      
-   
      
+
      
+(Makes it easier to fill a histogram with function values over a range.)
+
      
 
-In  cstdint.syn Header <cstdint>
+
      [
+Bellevue:
+]
      
+
+
+
      
+How do you specify the function so that it does not return negative
+values? If you do it is a bad construction. This requirement is already
+there. Where in each bin does one evaluate the function? In the middle.
+Need to revisit tomorrow.
+
      
+
+
      [
+Sophia Antipolis:
+]
      
+
+
+
      
+
      
+Bill is not requesting this.
+
      
+
      
+Marc Paterno: _Fn cannot return negative values at the points where the
+function is sampled. It is sampled in the middle of each bin. _Fn cannot
+return 0 everywhere it is sampled.
+
      
+
      
+Jens: lambda expressions are rvalues
+
      
+
      
+Add a library issue to provide an
+initializer_list<double> constructor for
+discrete_distribution.
+
      
+
      
+Marc Paterno: dislikes reference for _Fn parameter. Make it pass-by-value (to use lambda),
+use std::ref to wrap giant-state function objects.
+
      
+
      
+Daniel: See random_shuffle, pass-by-rvalue-reference.
+
      
+
      
+Daniel to draft wording.
+
      
+
      
+
+
      [
+Pre San Francisco, Daniel provided wording:
+]
      
+
+
+
      
+The here proposed changes of the WP refer to the current state of
+N2691.
+During the Sophia Antipolis meeting two different proposals came up
+regarding the functor argument type, either by value or by rvalue-reference.
+For consistence with existing conventions (state-free algorithms and the
+general_pdf_distribution c'tor signature) the author decided to propose a
+function argument that is provided by value. If severe concerns exists that
+stateful functions would be of dominant relevance, it should be possible to
+replace the two occurrences of Func by Func&& in this proposal as part
+of an editorial process.
+
      
+
+
+
+
      Proposed resolution:
      
+
+
      Non-concept version of the proposed resolution
      
+
+
        
+
      1. 
+
        
+In 26.5.8.5.1 [rand.dist.samp.discrete]/1, class discrete_distribution, just
+before the member declaration
+
        
+
+
        explicit discrete_distribution(const param_type& parm);
+
        
+
+
        
+insert:
+
        
+
+
+
        template<typename Func>
+discrete_distribution(result_type nf, double xmin, double xmax, Func fw);
+
        
+
        2. 
+
+
      2. 
+
        
+Between p.4 and p.5 insert a series of new paragraphs as part of the
+new member description::
+
        
+
        template<typename Func>
+discrete_distribution(result_type nf, double xmin, double xmax, Func fw);
+
        
+
+
        
+Complexity: Exactly nf invocations of fw.
+
        
+
        
+Requires:
+
        
+
          
+
        1. 
+fw shall be callable with one argument of type double, and shall
+return values of a type convertible to double;
          2. 
+
+
        2. If nf > 0, the relation xmin < xmax shall hold, and for all sample values
+xk, fw(xk) shall return a weight value wk that is non-negative, non-NaN,
+and non-infinity;
          3. 
+
+
        3. The following relations shall hold: nf ≥ 0, and 0 < S = w0+. . .+wn-1.
          4. 
+
+
        
+
+
        
+Effects:
+
        
+
          
+
        1. If nf == 0, sets n = 1 and lets the sequence w have length n = 1 and
+   consist of the single value w0 = 1.
          2. 
+
+
        2. 
+
          Otherwise, sets n = nf, deltax = (xmax - xmin)/n and xcent = xmin +
+0.5 * deltax.
          
+
          For each k = 0, . . . ,n-1, calculates:
+  xk = xcent + k * deltax
+  wk = fw(xk)
+
          
+
          3. 
+
        3. 
+
          Constructs a discrete_distribution object with probabilities:
          
+
          pk = wk/S  for k = 0, . . . , n-1.
+
          
+
          4. 
+
        
+
        
+
        3. 
+
      
+
+
      Concept version of the proposed resolution
      
+
+
+
        
+
      1. 
+
        
+In 26.5.8.5.1 [rand.dist.samp.discrete]/1, class discrete_distribution, just
+before the member declaration
+
        
+
+
        explicit discrete_distribution(const param_type& parm);
+
        
+
+
        
+insert:
+
        
+
+
+
        template<Callable<auto, double> Func>
+ requires Convertible<Func::result_type, double>
+discrete_distribution(result_type nf, double xmin, double xmax, Func fw);
+
        
+
        2. 
+
+
      2. 
+
        
+Between p.4 and p.5 insert a series of new paragraphs as part of the
+new member description::
+
        
+
        template<Callable<auto, double> Func>
+ requires Convertible<Func::result_type, double>
+discrete_distribution(result_type nf, double xmin, double xmax, Func fw);
+
        
+
+
        
+Complexity: Exactly nf invocations of fw.
+
        
+
        
+Requires:
+
        
+
          
+
        1. If nf > 0, the relation xmin < xmax shall hold, and for all sample values
+xk, fw(xk) shall return a weight value wk that is non-negative, non-NaN,
+and non-infinity;
          2. 
+
+
        2. The following relations shall hold: nf ≥ 0, and 0 < S = w0+. . .+wn-1.
          3. 
+
+
        
+
+
        
+Effects:
+
        
+
          
+
        1. If nf == 0, sets n = 1 and lets the sequence w have length n = 1 and
+   consist of the single value w0 = 1.
          2. 
+
+
        2. 
+
          Otherwise, sets n = nf, deltax = (xmax - xmin)/n and xcent = xmin +
+0.5 * deltax.
          
+
          For each k = 0, . . . ,n-1, calculates:
+  xk = xcent + k * deltax
+  wk = fw(xk)
+
          
+
          3. 
+
        3. 
+
          Constructs a discrete_distribution object with probabilities:
          
+
          pk = wk/S  for k = 0, . . . , n-1.
+
          
+
          4. 
+
        
+
        
+
        3. 
+
      
+
+
+
+
      Rationale:
      
+Addressed by
+N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
+
+
+
+
+
+
      
+
      794. piecewise_constant_distribution missing constructor
      
+
      Section: 26.5.8.5.2 [rand.dist.samp.pconst] Status: NAD Editorial
+ Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2009-03-09
      
+
      View all other issues in [rand.dist.samp.pconst].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+piecewise_constant_distribution should have a constructor like:
+
      
+
+
      template<class _Fn>
+   piecewise_constant_distribution(size_t _Count,
+            _Ty _Low, _Ty _High, _Fn& _Func);
+
      
+
+
      
+(Makes it easier to fill a histogram with function values over a range.
+The two (reference 793) make a sensible replacement for
+general_pdf_distribution.)
+
      
+
+
      [
+Sophia Antipolis:
+]
      
+
+
+
      
+
      
+Marc: uses variable width of bins and weight for each bin. This is not
+giving enough flexibility to control both variables.
+
      
+
      
+Add a library issue to provide an constructor taking an
+initializer_list<double> and _Fn for piecewise_constant_distribution.
+
      
+
      
+Daniel to draft wording.
+
      
+
      
+
+
      [
+Pre San Francisco, Daniel provided wording.
+]
      
+
+
+
      
+The here proposed changes of the WP refer to the current state of
+N2691.
+For reasons explained in 793, the author decided to propose a function
+argument that is provided by value. The issue proposes a c'tor signature,
+that does not take advantage of the full flexibility of
+piecewise_constant_distribution,
+because it restricts on a constant bin width, but the use-case seems to
+be popular enough to justify it's introduction.
+
      
+
+
+
+
      Proposed resolution:
      
+
+
      Non-concept version of the proposed resolution
      
+
+
        
+
      1. 
+
        
+In 26.5.8.5.2 [rand.dist.samp.pconst]/1, class piecewise_constant_distribution,
+just before the member declaration
+
        
+
+
        explicit piecewise_constant_distribution(const param_type& parm);
+
        
+
        
+insert:
+
        
+
        template<typename Func>
+piecewise_constant_distribution(size_t nf, RealType xmin, RealType xmax, Func fw);
+
        
+
        2. 
+
+
      2. 
+
        
+Between p.4 and p.5 insert a new sequence of paragraphs nominated
+below as [p5_1], [p5_2],
+[p5_3], and [p5_4] as part of the new member description:
+
        
+
+
        template<typename Func>
+piecewise_constant_distribution(size_t nf, RealType xmin, RealType xmax, Func fw);
+
        
+
        
+
        
+[p5_1] Complexity: Exactly nf invocations of fw.
+
        
+
        
+[p5_2] Requires:
+
        
+
          
+
        1. fw shall be callable with one argument of type RealType, and shall
+return values of a type convertible to double;
+
          2. 
+
        2. 
+For all sample values xk defined below, fw(xk) shall return a weight
+value wk that is non-negative, non-NaN, and non-infinity;
+
          3. 
+
        3. 
+The following relations shall hold: xmin < xmax, and
+0 < S = w0+. . .+wn-1.
+
          4. 
+
        
+
        
+[p5_3] Effects:
+
        
+
          
+
        1. 
+
          If nf == 0,
          
+ 
            
+ 
          1. 
+sets deltax = xmax - xmin, and
            2. 
+
          2.  lets the sequence w have length n = 1 and consist of the single
+    value w0 = 1, and
            3. 
+
          3.  lets the sequence b have length n+1 with b0 = xmin and 
+              b1 = xmax
+
            4. 
+
          
+
          2. 
+
        2. 
+
          Otherwise,
          
+
            
+
          1.  sets n = nf, deltax = (xmax - xmin)/n,
+                 xcent = xmin + 0.5 * deltax, and
+
            2. 
+
          2. lets the sequences w and b have length n and n+1, resp. and
            
+
            for each k = 0, . . . ,n-1, calculates:
+  dxk = k * deltax
+  bk = xmin + dxk
+  xk = xcent + dxk
+  wk = fw(xk),
+
             
+
             and
            
+
            3. 
+
          3.  sets bn = xmax
            4. 
+
          
+
          3. 
+
        3. 
+
          
+Constructs a piecewise_constant_distribution object with
+the above computed sequence b as the interval boundaries
+and with the probability densities:
+
          
+
          ρk = wk/(S * deltax)  for k = 0, . . . , n-1.
+
           
+
          4. 
+
        
+
        
+[p5_4] [Note: In this context, the subintervals [bk, bk+1) are commonly
+ known as the bins of a histogram. -- end note]
+ 
        
+
        
+
        
+
        3. 
+
      
+
+
      Concept version of the proposed resolution
      
+
+
        
+
      1. 
+
        
+In 26.5.8.5.2 [rand.dist.samp.pconst]/1, class piecewise_constant_distribution,
+just before the member declaration
+
        
+
+
        explicit piecewise_constant_distribution(const param_type& parm);
+
        
+
        
+insert:
+
        
+
        template<Callable<auto, RealType> Func>
+ requires Convertible<Func::result_type, double>
+piecewise_constant_distribution(size_t nf, RealType xmin, RealType xmax, Func fw);
+
        
+
        2. 
+
+
      2. 
+
        
+Between p.4 and p.5 insert a new sequence of paragraphs nominated
+below as [p5_1], [p5_2],
+[p5_3], and [p5_4] as part of the new member description:
+
        
+
+
        template<Callable<auto, RealType> Func>
+ requires Convertible<Func::result_type, double>
+piecewise_constant_distribution(size_t nf, RealType xmin, RealType xmax, Func fw);
+
        
+
        
+
        
+[p5_1] Complexity: Exactly nf invocations of fw.
+
        
+
        
+[p5_2] Requires:
+
        
+
          
+
        1. 
+For all sample values xk defined below, fw(xk) shall return a weight
+value wk that is non-negative, non-NaN, and non-infinity;
+
          2. 
+
        2. 
+The following relations shall hold: xmin < xmax, and
+0 < S = w0+. . .+wn-1.
+
          3. 
+
        
+
        
+[p5_3] Effects:
+
        
+
          
+
        1. 
+
          If nf == 0,
          
+ 
            
+ 
          1. 
+sets deltax = xmax - xmin, and
            2. 
+
          2.  lets the sequence w have length n = 1 and consist of the single
+    value w0 = 1, and
            3. 
+
          3.  lets the sequence b have length n+1 with b0 = xmin and 
+              b1 = xmax
+
            4. 
+
          
+
          2. 
+
        2. 
+
          Otherwise,
          
+
            
+
          1.  sets n = nf, deltax = (xmax - xmin)/n,
+                 xcent = xmin + 0.5 * deltax, and
+
            2. 
+
          2. lets the sequences w and b have length n and n+1, resp. and
            
+
            for each k = 0, . . . ,n-1, calculates:
+  dxk = k * deltax
+  bk = xmin + dxk
+  xk = xcent + dxk
+  wk = fw(xk),
+
             
+
             and
            
+
            3. 
+
          3.  sets bn = xmax
            4. 
+
          
+
          3. 
+
        3. 
+
          
+Constructs a piecewise_constant_distribution object with
+the above computed sequence b as the interval boundaries
+and with the probability densities:
+
          
+
          ρk = wk/(S * deltax)  for k = 0, . . . , n-1.
+
           
+
          4. 
+
        
+
        
+[p5_4] [Note: In this context, the subintervals [bk, bk+1) are commonly
+ known as the bins of a histogram. -- end note]
+ 
        
+
        
+
        
+
        3. 
+
      
+
+
+
+
      Rationale:
      
+Addressed by
+N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
+
+
+
+
+
+
      
+
      795. general_pdf_distribution should be dropped
      
+
      Section: X [rand.dist.samp.genpdf] Status: Dup
+ Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2008-03-11
      
+
      View all other issues in [rand.dist.samp.genpdf].
      
+
      View all issues with Dup status.
      
+
      Duplicate of: 732
      
+
      Discussion:
      
+
      
+general_pdf_distribution should be dropped. (It's a research topic in
+adaptive numerical integration.)
+
      
+
+
      [
+Stephan Tolksdorf notes:
+]
      
+
+
+
      
+This appears to be a duplicate of 732.
+
      
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
+
      
+
      796. ranlux48_base returns wrong value
      
+
      Section: 26.5.5 [rand.predef] Status: NAD
+ Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2008-02-27
      
+
      View all other issues in [rand.predef].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+The 10,000th value returned by ranlux48_base is supposed to be
+61839128582725. We get 192113843633948. (Note that the underlying
+generator was changed in Kona.)
+
      
+
+
      [
+Bellevue:
+]
      
+
+
+
      
+Submitter withdraws defect.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change 26.5.5 [rand.predef]/p5:
+
      
+
+
      
+
      typedef subtract_with_carry_engine<uint_fast64_t, 48, 5, 12> 
+        ranlux48_base; 
+
      
+
      
+Required behavior: The 10000th consecutive invocation of a default-constructed
+object of type ranlux48_base shall produce the value
+61839128582725 192113843633948.
+
      
+
      
+
+
+
+
+
+
      
+
      797. ranlux48 returns wrong value
      
+
      Section: 26.5.5 [rand.predef] Status: NAD
+ Submitter: P.J. Plauger Opened: 2008-02-09  Last modified: 2008-02-27
      
+
      View all other issues in [rand.predef].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+The 10,000th value returned by ranlux48 is supposed to be
+249142670248501. We get 88229545517833. (Note that this depends
+on ranlux48_base.)
+
      
+
      [
+Bellevue:
+]
      
+
+
+
      
+Submitter withdraws defect.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change 26.5.5 [rand.predef]/p6:
+
      
+
+
      
+
      typedef discard_block_engine<ranlux48_base, 389, 11> 
+        ranlux48
+
      
+
      
+Required behavior: The 10000th consecutive invocation of a default-constructed
+object of type ranlux48 shall produce the value
+249142670248501 88229545517833.
+
      
+
      
+
+
+
+
+
+
      
+
      799. [tr.rand.eng.mers] and [rand.eng.mers]
      
+
      Section: 26.5.3.2 [rand.eng.mers], TR1 5.1.4.2 [tr.rand.eng.mers] Status: NAD
+ Submitter: Stephan Tolksdorf Opened: 2008-02-18  Last modified: 2008-03-11
      
+
      View all other issues in [rand.eng.mers].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+TR1 5.1.4.2 [tr.rand.eng.mers](10) requires that operator== for the mersenne_twister
+returns true if and only if the states of two mersenne_twisters,
+consisting each of n integers between 0 and 2w - 1, are completely
+equal. This is a contradiction with TR1 5.1.1 [tr.rand.req](3) because the given
+definition of the state also includes the lower r bits of x(i-n), which
+will never be used to generate a random number. If two mersenne_twisters
+only differ in the lower bits of x(i-n) they will not compare equal,
+although they will produce an identical sequence of random numbers.
+
      
+
+
      
+26.5.3.2 [rand.eng.mers] in the latest C++ draft does not specify the behaviour
+of operator== but uses a similar definition of the state and, just like
+TR1 5.1.4.2 [tr.rand.eng.mers], requires the textual representation of a
+mersenne_twister_engine to consist of Xi-n to Xi-1, including the
+lower bits of Xi-n. This leads to two problems: First, the
+unsuspecting implementer is likely to erroneously compare the lower r
+bits of Xi-n in operator==. Second, if only the lower r bits differ,
+two mersenne_twister_engines will compare equal (if correctly
+implemented) but have different textual representations, which
+conceptually is a bit ugly.
+
      
+
+
      
+I propose that a paragraph or footnote is added to 26.5.3.2 [rand.eng.mers] which
+clarifies that the lower r bits of Xi-n are not to be compared in
+operator== and operator!=. It would only be consequent if furthermore
+the specification for the textual respresentation was changed to
+Xi-n bitand ((2w - 1) - (2r - 1)), Xi-(n-1), ...,  Xi-1 or
+something similar.
+
      
+
+
      
+These changes would likely have no practical effect, but would allow an
+implementation that does the right thing to be standard-conformant.
+
      
+
+
      [
+Bellevue:
+]
      
+
+
+
      
+
      
+Fermi Lab has no objection to the proposed change. However it feels that
+more time is needed to check the details, which would suggest a change
+to REVIEW.
+
      
+
      
+Bill feels that this is NAD, not enough practical importance to abandon
+the simple definition of equality, and someone would have to do a lot
+more study to ensure that all cases are covered for a very small
+payback. The submitter admits that "These changes would likely have no
+practical effect,", and according to Plum's razor this means that it is
+not worth the effort!
+
      
+
      
+Revisted: Agree that the fact that there is no practical difference means that no change can be justified.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+In 26.5.3.2 [rand.eng.mers]:
+
      
+
+
      
+
      
+Insert at the end of para 2.:
+
      
+
+
      
+[Note: The lower r bits of Xi-n do not influence
+the state transition and hence should not be compared when comparing two
+mersenne_twister_engine objects. -- end note]
+
      
+
+
      
+In para 5. change:
+
      
+
+
      
+The textual representation of xi consists of the values of
+Xi-n bitand ((2w - 1) - (2r - 1)),  Xi-(n-1),
+..., Xi-1, in that order.
+
      
+
      
+
+
+
+
+
+
      
+
      800. Issues in 26.4.7.1 [rand.util.seedseq](6)
      
+
      Section: 26.5.7.1 [rand.util.seedseq] Status: NAD Editorial
+ Submitter: Stephan Tolksdorf Opened: 2008-02-18  Last modified: 2009-03-09
      
+
      View all other issues in [rand.util.seedseq].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+The for-loop in the algorithm specification has n iterations, where n is
+defined to be end - begin, i.e. the number of supplied w-bit quantities.
+Previous versions of this algorithm and the general logic behind it
+suggest that this is an oversight and that in the context of the
+for-loop n should be the number of full 32-bit quantities in b (rounded
+upwards). If w is 64, the current algorithm throws away half of all bits
+in b. If w is 16, the current algorithm sets half of all elements in v
+to 0.
+
      
+
+
      
+There are two more minor issues:
+
      
+
+
        
+
      • 
+Strictly speaking end - begin is not defined since
+InputIterator is not required to be a random access iterator.
+
        • 
+
      • 
+Currently all integral types are allowed as input to the seed_seq
+constructor, including bool. IMHO allowing bools unnecessarily
+complicates the implementation without any real benefit to the user.
+I'd suggest to exclude bools as input.
+
        • 
+
      
+
+
      [
+Bellevue:
+]
      
+
+
+
      
+Move to OPEN Bill will try to propose a resolution by the next meeting.
+
      
+
+
      [
+post Bellevue:  Bill provided wording.
+]
      
+
+
+
      
+This issue is made moot if 803 is accepted.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Replace 26.5.7.1 [rand.util.seedseq] paragraph 6 with:
+
      
+
+
      
+
      
+Effects: Constructs a seed_seq object by effectively concatenating the
+low-order u bits of each of the elements of the supplied sequence [begin,
+end)
+in ascending order of significance to make a (possibly very large) unsigned
+binary number b having a total of n bits, and then carrying out the
+following
+algorithm:
+
      
+
+
      for( v.clear(); n > 0; n -= 32 )
+   v.push_back(b mod 232), b /= 232;
+
      
+
      
+
+
+
      Rationale:
      
+Addressed by
+N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
+
+
+
+
+
+
      
+
      802. knuth_b returns wrong value
      
+
      Section: 26.5.5 [rand.predef] Status: NAD
+ Submitter: P.J. Plauger Opened: 2008-02-20  Last modified: 2008-03-17
      
+
      View all other issues in [rand.predef].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+The 10,000th value returned by knuth_b is supposed to be
+1112339016. We get 2126698284.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 26.5.5 [rand.predef]/p8:
+
      
+
+
      
+
      typedef shuffle_order_engine<minstd_rand0, 256> 
+        knuth_b; 
+
      
+
      
+Required behavior: The 10000th consecutive invocation of a default-constructed
+object of type knuth_b shall produce the value
+1112339016 2126698284.
+
      
+
      
+
+
+
      [
+Bellevue: Submitter withdraws defect. "We got the wrong value for entirely the right reasons". NAD.
+]
      
+
+
+
+
+
+
      
+
      803. Simplification of seed_seq::seq_seq
      
+
      Section: 26.5.7.1 [rand.util.seedseq] Status: NAD Editorial
+ Submitter: Charles Karney Opened: 2008-02-22  Last modified: 2009-03-09
      
+
      View all other issues in [rand.util.seedseq].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+seed_seq(InputIterator begin, InputIterator end); constructs a seed_seq
+object repacking the bits of supplied sequence [begin, end) into a
+32-bit vector.
+
      
+
      
+This repacking triggers several problems:
+
      
+
        
+
      1. 
+Distinctness of the output of seed_seq::generate required the
+introduction of the initial "if (w < 32) v.push_back(n);"  (Otherwise
+the unsigned short vectors [1, 0] and [1] generate the same sequence.)
+
        2. 
+
      2. 
+Portability demanded the introduction of the template parameter u.
+(Otherwise some sequences could not be obtained on computers where no
+integer types are exactly 32-bits wide.)
+
        3. 
+
      3. 
+The description and algorithm have become unduly complicated.
+
        4. 
+
      
+
      
+I propose simplifying this seed_seq constructor to be "32-bit only".
+Despite it's being simpler, there is NO loss of functionality (see
+below).
+
      
+
      
+Here's how the description would read
+
      
+
      
+
      
+26.5.7.1 [rand.util.seedseq] Class seed_seq
+
      
+
+
      
+
      template<class InputIterator>
+  seed_seq(InputIterator begin, InputIterator end);
+
      
+
      
+
      
+5 Requires: NO CHANGE
+
      
+
      
+6 Effects: Constructs a seed_seq object by
+
      
+
      
+
      for (InputIterator s = begin; s != end; ++s)
+   v.push_back((*s) mod 2^32);
+
      
+
      
+
      
+
      
+
      
+
+
      
+Discussion:
+
      
+
      
+The chief virtues here are simplicity, portability, and generality.
+
      
+
        
+
      • 
+Simplicity -- compare the above specification with the
+n2461 proposal.
+
        • 
+
      • 
+Portability -- with iterator_traits<InputIterator>::value_type =
+uint_least32_t the user is guaranteed to get the same behavior across
+platforms.
+
        • 
+
      • 
+Generality -- any behavior that the
+n2461
+proposal can achieve can be
+obtained with this simpler proposal (albeit with a shuffling of bits
+in the input sequence).
+
        • 
+
      
+
      
+Arguments (and counter-arguments) against making this change (and
+retaining the
+n2461
+behavior) are:
+
      
+
        
+
      • 
+
        
+The user can pass an array of unsigned char and seed_seq will nicely
+ repack it.
+
        
+
        
+ Response: So what?  Consider the seed string "ABC".  The
+ n2461
+ proposal results in
+
        
+
        v = { 0x3, 0x434241 };
+
        
+
        
+while the simplified proposal yields
+
        
+
        v = { 0x41, 0x42, 0x43 };
+
        
+
        
+The results produced by seed_seq::generate with the two inputs are
+different but nevertheless equivalently "mixed up" and this remains
+true even if the seed string is long.
+
        
+
        • 
+
      • 
+
        
+With long strings (e.g., with bit-length comparable to the number of
+ bits in the state), v is longer (by a factor of 4) with the simplified
+ proposal and seed_seq::generate will be slower.
+
        
+
        
+Response: It's unlikely that the efficiency of seed_seq::generate will
+ be a big issue.  If it is, the user is free to repack the seed vector
+ before constructing seed_seq.
+
        
+
        • 
+
      • 
+
        
+A user can pass an array of 64-bit integers and all the bits will be
+ used.
+
        
+
        
+ Response: Indeed.  However, there are many instances in the 
+ n2461
+ where integers are silently coerced to a narrower width and this
+ should just be a case of the user needing to read the documentation.
+ The user can of course get equivalent behavior by repacking his seed
+ into 32-bit pieces.  Furthermore, the unportability of the 
+ n2461
+ proposal with
+
        
+
        unsigned long s[] = {1, 2, 3, 4};
+seed_seq q(s, s+4);
+
        
+
        
+ which typically results in v = {1, 2, 3, 4} on 32-bit machines and in
+v = {1, 0, 2, 0, 3, 0, 4, 0} on 64-bit machines is a major pitfall for
+ unsuspecting users.
+
        
+
        • 
+
      
+
+
      
+Note: this proposal renders moot issues 782 and 800.
+
      
+
+
      [
+Bellevue:
+]
      
+
+
+
      
+Walter needs to ask Fermilab for guidance. Defer till tomorrow. Bill likes the proposed resolution.
+
      
+
+
      [
+Sophia Antipolis:
+]
      
+
+
+
      
+
      
+Marc Paterno wants portable behavior between 32bit and 64bit machines;
+we've gone to significant trouble to support portability of engines and
+their values.
+
      
+
      
+Jens: the new algorithm looks perfectly portable
+
      
+
      
+Marc Paterno to review off-line.
+
      
+
      
+Modify the proposed resolution to read "Constructs a seed_seq object by the following algorithm ..."
+
      
+
      
+Disposition: move to review; unanimous consent.
+
      
+
      
+(moots 782 and 800)
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change 26.5.7.1 [rand.util.seedseq]:
+
      
+
+
      
+
      template<class InputIterator, 
+  size_t u = numeric_limits<iterator_traits<InputIterator>::value_type>::digits>
+  seed_seq(InputIterator begin, InputIterator end);
+
      
+
      
+
      
+-5- Requires: InputIterator shall satisfy the requirements of an input iterator (24.1.1)
+such that iterator_traits<InputIterator>::value_type shall denote an integral type.
+
      
+
      
+-6- Constructs a seed_seq object by the following algorithm rearranging some or all of the bits of the supplied sequence
+[begin,end) of w-bit quantities into 32-bit units, as if by the following: 
+
      
+
      
+First extract the rightmost u bits from each of the n = end
+- begin elements of the supplied sequence and concatenate all the
+extracted bits to initialize a single (possibly very large) unsigned
+binary number, b = ∑n-1i=0 (begin[i] 
+mod 2u) · 2w·i (in which the bits of each begin[i]
+are treated as denoting an unsigned quantity). Then carry out 
+the following algorithm:
+
      
+
      
+v.clear(); 
+if ($w$ < 32) 
+  v.push_back($n$); 
+for( ; $n$ > 0; --$n$) 
+  v.push_back(b mod 232), b /= 232;
+
      
+
      
+
      
+for (InputIterator s = begin; s != end; ++s)
+   v.push_back((*s) mod 232);
+
      
+
      
+
      
+
      
+
+
+
      Rationale:
      
+Addressed by
+N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
+
+
+
+
+
+
      
+
      812. unsolicited multithreading considered harmful?
      
+
      Section: 25.5.1 [alg.sort] Status: NAD Editorial
+ Submitter: Paul McKenney Opened: 2008-02-27  Last modified: 2008-09-17
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+Multi-threading is a good thing, but unsolicited multi-threading can
+potentially be harmful.  For example, sort() performance might be
+greatly increased via a multithreaded implementation.  However, such
+a multithreaded implementation could result in concurrent invocations
+of the user-supplied comparator.  This would in turn result in problems
+given a caching comparator that might be written for complex sort keys.
+Please note that this is not a theoretical issue, as multithreaded
+implementations of sort() already exist.
+
      
+
      
+Having a multithreaded sort() available is good, but it should not
+be the default for programs that are not explicitly multithreaded.
+Users should not be forced to deal with concurrency unless they have
+asked for it.
+
      
+
+
      [
+This may be covered by
+N2410
+Thread-Safety in the Standard Library (Rev 1).
+]
      
+
+
+
+
      Proposed resolution:
      
+
      
+
      
+
+
+
      Rationale:
      
+This is already covered by 17.6.5.6/20 in N2723.
+
+
+
+
+
+
      
+
      825. Missing rvalues reference stream insert/extract operators?
      
+
      Section: 19.5.2.2 [syserr.errcode.overview], 20.8.10.2.8
+[util.smartptr.shared.io], 22.4.8 [facets.examples], 20.3.6.3
+[bitset.operators], 26.4.6 [complex.ops], 27.6 [stream.buffers], 28.9
+[re.submatch] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2008-04-10  Last modified: 2009-07-13
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+Should the following use rvalues references to stream in insert/extract
+operators?
+
      
+
+
        
+
      • 19.5.2.2 [syserr.errcode.overview]
        • 
+
      • 20.8.10.2.8 [util.smartptr.shared.io]
        • 
+
      • 22.4.8 [facets.examples]
        • 
+
      • 20.3.6.3 [bitset.operators]
        • 
+
      • 26.4.6 [complex.ops]
        • 
+
      • Doubled signatures in 27.6 [stream.buffers] for character inserters
+(ref 27.7.2.6.4 [ostream.inserters.character])
++ definition 27.7.2.6.4 [ostream.inserters.character]
        • 
+
      • 28.9 [re.submatch]
        • 
+
      
+
+
      [
+Sophia Antipolis
+]
      
+
+
+
      
+Agree with the idea in the issue, Alisdair to provide wording.
+
      
+
+
      [
+Daniel adds 2009-02-14:
+]
      
+
+
+
      
+The proposal given in the paper
+N2831
+apparently resolves this issue.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+The cited paper is an earlier version of
+N2844,
+which changed the rvalue reference binding rules.
+That paper includes generic templates
+operator<< and operator>>
+that adapt rvalue streams.
+
      
+
      
+We therefore agree with Daniel's observation.
+Move to NAD Editorial.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+
      
+
+
+
+
+
+
      
+
      826. Equivalent of %'d, or rather, lack thereof?
      
+
      Section: 22.4.2.2 [locale.nm.put] Status: NAD
+ Submitter: Peter Dimov Opened: 2008-04-07  Last modified: 2008-06-18
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+In the spirit of printf vs iostream...
+
      
+
+
      
+POSIX printf says that %'d should insert grouping characters (and the
+implication is that in the absence of ' no grouping characters are
+inserted). The num_put facet, on the other hand, seems to always insert
+grouping characters. Can this be considered a defect worth fixing for
+C++0x? Maybe ios_base needs an additional flag?
+
      
+
+
      [
+Pablo Halpern:
+]
      
+
+
+
      
+I'm not sure it constitutes a defect, but I would be in favor of adding
+another flag (and corresponding manipulator).
+
      
+
+
      [
+Martin Sebor:
+]
      
+
+
+
      
+I don't know if it qualifies as a defect but I agree that there
+should be an easy way to control whether the thousands separator
+should or shouldn't be inserted. A new flag would be in line with
+the current design of iostreams (like boolalpha, showpos, or
+showbase).
+
      
+
+
      [
+Sophia Antipolis:
+]
      
+
+
+
      
+This is not a part of C99. LWG suggests submitting a paper may be appropriate.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+
      
+
+
+
+
+
+
      
+
      830. Incomplete list of char_traits specializations
      
+
      Section: 21.2 [char.traits] Status: NAD Editorial
+ Submitter: Dietmar Kühl Opened: 2008-04-23  Last modified: 2009-07-13
      
+
      View all other issues in [char.traits].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+  Paragraph 4 of 21.2 [char.traits] mentions that this
+  section specifies two specializations (char_traits<char>
+  and (char_traits<wchar_t>). However, there are actually
+  four specializations provided, i.e. in addition to the two above also
+  char_traits<char16_t> and char_traits<char32_t>).
+  I guess this was just an oversight and there is nothing wrong with just
+  fixing this.
+
      
+
+
      [
+Alisdair adds:
+]
      
+
+
      
+char_traits< char16/32_t >
+should also be added to <ios_fwd> in 27.3 [iostream.forward], and all the specializations
+taking a char_traits parameter in that header.
+
      
+
+
      [
+Sophia Antipolis:
+]
      
+
+
+
      
+
      
+Idea of the issue is ok.
+
      
+
      
+Alisdair to provide wording, once that wording arrives, move to review.
+
      
+
+
      
+
+
      [
+2009-05-04 Alisdair adds:
+]
      
+
+
+
      
+
      
+The main point of the issue was resolved editorially in
+N2723,
+so we are
+close to NAD Editorial.
+However, exploring the issue we found a second tweak was necessary for
+<iosfwd> and that is still outstanding, so here are the words I am long
+overdue delivering:
+
      
+
+
      [
+Howard:  I've put Alisdair's words into the proposed wording section and
+moved the issue to Review.
+]
      
+
+
+
      
+
+
      [
+Original proposed wording.
+]
      
+
+
+
      
+
+
      
+  Replace paragraph 4 of 21.2 [char.traits] by:
+
      
+
      
+
      
+  This subclause specifies a struct template, char_traits<charT>,
+  and four explicit specializations of it, char_traits<char>,
+  char_traits<char16_t>, char_traits<char32_t>, and
+  char_traits<wchar_t>, all of which appear in the header
+  <string> and satisfy the requirements below.
+
      
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree.  Move to NAD Editorial.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change Forward declarations 27.3 [iostream.forward]:
+
      
+
+
      
+
      
+Header <iosfwd> synopsis
+
      
+
      namespace std {
+   template<class charT> class char_traits;
+   template<> class char_traits<char>;
+   template<> class char_traits<char16_t>;
+   template<> class char_traits<char32_t>;
+   template<> class char_traits<wchar_t>;
+...
+}
+
      
+
      
+
+
+
+
+
+
      
+
      831. wrong type for not_eof()
      
+
      Section: 21.2.3 [char.traits.specializations] Status: NAD Editorial
+ Submitter: Dietmar Kühl Opened: 2008-04-23  Last modified: 2008-06-19
      
+
      View all other issues in [char.traits.specializations].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+  In Table 56 (Traits requirements) the not_eof() member function
+  is using an argument of type e which denotes an object of
+  type X::int_type. However, the specializations in
+  21.2.3 [char.traits.specializations] all use char_type.
+  This would effectively mean that the argument type actually can't
+  represent EOF in the first place. I'm pretty sure that the type used
+  to be int_type which is quite obviously the only sensible
+  argument.
+
      
+
      
+  This issue is close to being editorial. I suspect that the proposal
+  changing this section to include the specializations for char16_t
+  and char32_t accidentally used the wrong type.
+
      
+
+
+
      Proposed resolution:
      
+
      
+  In 21.2.3.1 [char.traits.specializations.char],
+  21.2.3.2 [char.traits.specializations.char16_t],
+  21.2.3.3 [char.traits.specializations.char32_t], and
+   [char.traits.specializations.wchar_t] correct the
+  argument type from char_type to int_type.
+
      
+
+
+
      Rationale:
      
+Already fixed in WP.
+
+
+
+
+
+
      
+
      832. Applying constexpr to System error support
      
+
      Section: 19.5 [syserr] Status: NAD
+ Submitter: Beman Dawes Opened: 2008-05-14  Last modified: 2008-09-17
      
+
      View all other issues in [syserr].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+Initialization of objects of class error_code
+(19.5.2 [syserr.errcode]) and class
+error_condition (19.5.3 [syserr.errcondition]) can be made simpler and more reliable by use of
+the new constexpr feature 
+[N2349]
+of C++0x. Less code will need to be
+generated for both library implementations and user programs when
+manipulating constant objects of these types. 
+
      
+
+
      
+This was not proposed originally because the constant expressions
+proposal was moving into the standard at about the same time as the
+Diagnostics Enhancements proposal 
+[N2241],
+and it wasn't desirable to
+make the later depend on the former. There were also technical concerns
+as to how constexpr would apply to references. Those concerns are now
+resolved; constexpr can't be used for references, and that fact is
+reflected in the proposed resolution.
+
      
+
+
      
+Thanks to Jens Maurer, Gabriel Dos Reis, and Bjarne Stroustrup for clarification of constexpr requirements.
+
      
+
+
      
+LWG issue 804 is related in that it raises the question of whether the
+exposition only member cat_ of class error_code (19.5.2 [syserr.errcode]) and class
+error_condition (19.5.3 [syserr.errcondition]) should be presented as a reference or pointer.
+While in the context of 804 that is arguably an editorial question,
+presenting it as a pointer becomes more or less required with this
+proposal, given constexpr does not play well with references. The
+proposed resolution thus changes the private member to a pointer, which
+also brings it in sync with real implementations.
+
      
+
+
      [
+Sophia Antipolis:
+]
      
+
+
+
      
+On going question of extern pointer vs. inline functions for interface.
+
      
+
+
      [
+Pre-San Francisco:
+]
      
+
+
+
      
+
      
+Beman Dawes reports that this proposal is unimplementable, and thus NAD.
+
      
+
      
+Implementation would require constexpr objects of classes derived
+from class error_category, which has virtual functions, and that is
+not allowed by the core language. This was determined when trying to
+implement the proposal using a constexpr enabled compiler provided
+by Gabriel Dos Reis, and subsequently verified in discussions with
+Gabriel and Jens Maurer.
+
      
+
+
      
+
+
+
      Proposed resolution:
      
+
      
+The proposed wording assumes the LWG 805 proposed wording has been
+applied to the WP, resulting in the former posix_category being renamed
+generic_category. If 805 has not been applied, the names in this
+proposal must be adjusted accordingly.
+
      
+
+
      
+Change 19.5.1.1 [syserr.errcat.overview] Class
+error_category overview error_category synopsis  as
+indicated:
+
      
+
+
      const error_category& get_generic_category();
+const error_category& get_system_category();
+
+static extern const error_category&* const generic_category = get_generic_category();
+static extern const error_category&* const native_category system_category = get_system_category();
+
      
+
+
      
+Change 19.5.1.5 [syserr.errcat.objects] Error category objects as indicated:
+
      
+
+
      
+
      extern const error_category&* const get_generic_category();
+
      
+
      
+Returns: A reference generic_category shall point
+to an a statically initialized object of a type derived from
+class error_category.
+
      
+
+
      
+Remarks: The object's default_error_condition and equivalent virtual
+functions shall behave as specified for the class error_category. The
+object's name virtual function shall return a pointer to the string
+"GENERIC".
+
      
+
+
      extern const error_category&* const get_system_category();
+
      
+
+
      
+Returns: A reference system_category shall point
+to an a statically
+initialized object of a type derived from class error_category.
+
      
+
+
      
+Remarks:  The object's equivalent virtual functions shall behave as
+specified for class error_category. The object's name virtual function
+shall return a pointer to the string "system". The object's
+default_error_condition virtual function shall behave as follows:
+
      
+
+
      
+If the argument ev corresponds to a POSIX errno value posv, the function
+shall return error_condition(posv, generic_category). Otherwise, the
+function shall return error_condition(ev, system_category). What
+constitutes correspondence for any given operating system is
+unspecified. [Note: The number of potential system error codes is large
+and unbounded, and some may not correspond to any POSIX errno value.
+Thus implementations are given latitude in determining correspondence.
+-- end note]
+
      
+
      
+
+
      
+Change 19.5.2.2 [syserr.errcode.overview] Class error_code overview as indicated:
+
      
+
+
      class error_code {
+public:
+  ...;
+  constexpr error_code(int val, const error_category&* cat);
+  ...
+  void assign(int val, const error_category&* cat);
+  ...
+  const error_category&* category() const;
+  ...
+private:
+  int val_;                    // exposition only
+  const error_category&* cat_; // exposition only
+
      
+
+
      
+Change 19.5.2.3 [syserr.errcode.constructors] Class error_code constructors as indicated:
+
      
+
+
      
+
      constexpr error_code(int val, const error_category&* cat);
+
      
+
      
+Effects: Constructs an object of type error_code.
+
      
+
      
+Postconditions: val_ == val and cat_ == cat.
+
      
+
      
+Throws: Nothing.
+
      
+
      
+
+
      
+Change 19.5.2.4 [syserr.errcode.modifiers] Class error_code modifiers  as indicated:
+
      
+
+
      
+
      void assign(int val, const error_category&* cat);
+
      
+
      
+Postconditions: val_ == val and cat_ == cat.
+
      
+
      
+Throws: Nothing.
+
      
+
      
+
+
      
+Change 19.5.2.5 [syserr.errcode.observers] Class error_code observers  as indicated:
+
      
+
+
      
+
      const error_category&* category() const;
+
      
+
+
      
+Returns: cat_.
+
      
+
      
+Throws: Nothing.
+
      
+
      
+
+
      
+Change 19.5.3.2 [syserr.errcondition.overview] Class error_condition overview   as indicated:
+
      
+
+
      
+
      class error_condition {
+public:
+  ...;
+  constexpr error_condition(int val, const error_category&* cat);
+  ...
+  void assign(int val, const error_category&* cat);
+  ...
+  const error_category&* category() const;
+  ...
+private:
+  int val_;                    // exposition only
+  const error_category&* cat_; // exposition only
+
      
+
      
+
+
      
+Change 19.5.3.3 [syserr.errcondition.constructors] Class error_condition constructors as indicated:
+
      
+
+
      
+
      constexpr error_condition(int val, const error_category&* cat);
+
      
+
      
+Effects: Constructs an object of type error_condition.
+
      
+
      
+Postconditions: val_ == val and cat_ == cat.
+
      
+
      
+Throws: Nothing.
+
      
+
      
+
+
      
+Change 19.5.3.4 [syserr.errcondition.modifiers] Class error_condition modifiers as indicated:
+
      
+
+
      
+
      void assign(int val, const error_category&* cat);
+
      
+
      
+Postconditions: val_ == val and cat_ == cat.
+
      
+
      
+Throws: Nothing.
+
      
+
      
+
+
      
+Change 19.5.3.5 [syserr.errcondition.observers] Class error_condition observers as indicated:
+
      
+
+
      
+
      const error_category&* category() const;
+
      
+
      
+Returns: cat_.
+
      
+
      
+Throws: Nothing.
+
      
+
      
+
+
      
+Throughout 19.5 [syserr] System error support, change "category()."  to "category()->".
+Appears approximately six times.
+
      
+
+
      
+[Partially Editorial] In 19.5.4 [syserr.compare] Comparison operators,
+paragraphs 2 and 4, change "category.equivalent("  to
+"category()->equivalent(".
+
      
+
+
      
+Change 19.5.5.1 [syserr.syserr.overview] Class system_error overview as indicated:
+
      
+
+
      public:
+  system_error(error_code ec, const string& what_arg);
+  system_error(error_code ec);
+  system_error(int ev, const error_category&* ecat,
+      const string& what_arg);
+  system_error(int ev, const error_category&* ecat);
+
      
+
+
      
+Change 19.5.5.2 [syserr.syserr.members] Class system_error members as indicated:
+
      
+
+
      
+
      system_error(int ev, const error_category&* ecat, const string& what_arg);
+
      
+
      
+
      
+Effects: Constructs an object of class system_error.
+
      
+
      
+Postconditions: code() == error_code(ev, ecat) and
+strcmp(runtime_error::what(), what_arg.c_str()) == 0.
+
      
+
      
+
+
      system_error(int ev, const error_category&* ecat);
+
      
+
      
+
      
+Effects: Constructs an object of class system_error.
+
      
+
      
+Postconditions: code() == error_code(ev, ecat) and
+strcmp(runtime_error::what(), "") == 0.
+
      
+
      
+
      
+
+
+
+
      Rationale:
      
+
      [
+San Francisco:
+]
      
+
+
+
      
+NAD because Beman said so.
+
      
+
+
+
+
+
+
      
+
      833. Freestanding implementations header list needs review for C++0x
      
+
      Section: 17.6.1.3 [compliance] Status: NAD
+ Submitter: Beman Dawes Opened: 2008-05-14  Last modified: 2009-07-16
      
+
      View all other issues in [compliance].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+Once the C++0x standard library is feature complete, the LWG needs to
+review 17.6.1.3 [compliance] Freestanding implementations header list to
+ensure it reflects LWG consensus.
+
      
+
+
      [
+San Francisco:
+]
      
+
+
+
      
+
      
+This is a placeholder defect to remind us to review the table once we've
+stopped adding headers to the library.
+
      
+
      
+Three new headers that need to be added to the list:
+
      
+
      <initializer_list> <concept> <iterator_concepts>
+
      
+
      
+<iterator_concepts>, in particular, has lots of stuff
+that isn't needed, so maybe the stuff that is needed should be broken
+out into a separate header.
+
      
+
      
+Robert: What about reference_closure? It's currently in
+<functional>.
+
      
+
      
+
+
      [
+Post Summit Daniel adds:
+]
      
+
+
+
      
+
        
+
      1. 
+The comment regarding reference_closure seems moot since it was just
+recently decided to remove that.
+
        2. 
+
      2. 
+A reference to proposal
+N2814
+("Fixing freestanding") should be added. This
+paper e.g. proposes to add only <initializer_list> to the include list
+of freestanding.
+
        3. 
+
      
+
      
+
+
      [
+2009-07 Frankfurt:
+]
      
+
+
+
      
+
      
+Addressed by paper
+N2814.
+
      
+
      
+Move to NAD.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      837. 
+   basic_ios::copyfmt() overly loosely specified
+ 
      
+
      Section: 27.5.4.2 [basic.ios.members] Status: NAD Editorial
+ Submitter: Martin Sebor Opened: 2008-05-17  Last modified: 2009-07-13
      
+
      View other active issues in [basic.ios.members].
      
+
      View all other issues in [basic.ios.members].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+   
      
+
+The basic_ios::copyfmt() member function is specified in 27.5.4.2 [basic.ios.members] to have the following effects:
+
+   
      
+   
      
+
+Effects: If (this == &rhs) does
+nothing. Otherwise assigns to the member objects of *this
+the corresponding member objects of rhs, except that
+
+     
        
+       
      • 
+
+rdstate() and rdbuf() are left unchanged;
+
+       
        • 
+       
      • 
+
+exceptions() is altered last by
+calling exceptions(rhs.except)
+
+       
        • 
+       
      • 
+
+the contents of arrays pointed at by pword
+and iword are copied not the pointers themselves
+
+       
        • 
+     
      
+   
      
+   
      
+
+Since the rest of the text doesn't specify what the member objects
+of basic_ios are this seems a little too loose.
+
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to NAD Editorial.
+
      
+
+
+
      Proposed resolution:
      
+
      
+
+I propose to tighten things up by adding a Postcondition clause
+to the function like so:
+
+   
      
+   
      
+     Postconditions:
+
+     
+       
+         
+           
+         
+         
+           
+           
+         
+       
+       
+         
+           
+           
+         
+          
+           
+           
+         
+          
+           
+           
+         
+          
+           
+           
+         
+          
+           
+           
+         
+          
+           
+           
+         
+          
+           
+           
+         
+          
+           
+           
+         
+          
+           
+           
+         
+       
+     
      copyfmt() postconditions
      ElementValue
      rdbuf()unchanged
      tie()rhs.tie()
      rdstate()unchanged
      exceptions()rhs.exceptions()
      flags()rhs.flags()
      width()rhs.width()
      precision()rhs.precision()
      fill()rhs.fill()
      getloc()rhs.getloc()
      
+   
      
+   
      
+
+The format of the table follows Table 117 (as
+of N2588): basic_ios::init()
+effects.
+
+   
      
+   
      
+
+The intent of the new table is not to impose any new requirements or
+change existing ones, just to be more explicit about what I believe is
+already there.
+
+   
      
+ 
+
+
+
+
      
+
      839. Maps and sets missing splice operation
      
+
      Section: 23.4 [associative], 23.5 [unord] Status: NAD Future
+ Submitter: Alan Talbot Opened: 2008-05-18  Last modified: 2009-07-16
      
+
      View all other issues in [associative].
      
+
      View all issues with NAD Future status.
      
+
      Discussion:
      
+
      
+Splice is a very useful feature of list. This functionality is also very
+useful for any other node based container, and I frequently wish it were
+available for maps and sets. It seems like an omission that these
+containers lack this capability. Although the complexity for a splice is
+the same as for an insert, the actual time can be much less since the
+objects need not be reallocated and copied. When the element objects are
+heavy and the compare operations are fast (say a map<int, huge_thingy>)
+this can be a big win.
+
      
+
+
      
+Suggested resolution:
+
      
+
+
      
+Add the following signatures to map, set, multimap, multiset, and the unordered associative containers:
+
      
+
       
+void splice(list<T,Allocator>&& x);
+void splice(list<T,Allocator>&& x, const_iterator i);
+void splice(list<T,Allocator>&& x, const_iterator first, const_iterator last);
+
      
+
+
      
+Hint versions of these are also useful to the extent hint is useful.
+(I'm looking for guidance about whether hints are in fact useful.)
+
      
+ 
+
       
+void splice(const_iterator position, list<T,Allocator>&& x);
+void splice(const_iterator position, list<T,Allocator>&& x, const_iterator i);
+void splice(const_iterator position, list<T,Allocator>&& x, const_iterator first, const_iterator last);
+
      
+
+
      [
+Sophia Antipolis:
+]
      
+
+
+
      
+
      
+Don't try to splice "list" into the other containers, it should be container-type.
+
      
+
      
+forward_list already has splice_after.
+
      
+
      
+Would "splice" make sense for an unordered_map?
+
      
+
      
+Jens, Robert: "splice" is not the right term, it implies maintaining ordering in lists.
+
      
+
      
+Howard: adopt?
+
      
+
      
+Jens: absorb?
+
      
+
      
+Alan: subsume?
+
      
+
      
+Robert: recycle?
+
      
+
      
+Howard: transfer? (but no direction)
+
      
+
      
+Jens: transfer_from. No.
+
      
+
      
+Alisdair: Can we give a nothrow guarantee? If your compare() and hash() doesn't throw, yes.
+
      
+
      
+Daniel: For unordered_map, we can't guarantee nothrow.
+
      
+
      
+
+
      [
+San Francisco:
+]
      
+
+
+
      
+
      
+Martin: this would possibly outlaw an implementation technique that is
+currently in use; caching nodes in containers.
+
      
+
      
+Alan: if you cache in the allocator, rather than the individual
+container, this proposal doesn't interfere with that.
+
      
+
      
+Martin: I'm not opposed to this, but I'd like to see an implementation
+that demonstrates that it works.
+
      
+
      
+
+
      [
+2009-07 Frankfurt:
+]
      
+
+
+
      
+NAD Future.
+
      
+
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      840. pair default template argument
      
+
      Section: 20.3.3 [pairs] Status: NAD
+ Submitter: Thorsten Ottosen Opened: 2008-05-23  Last modified: 2008-06-18
      
+
      View other active issues in [pairs].
      
+
      View all other issues in [pairs].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+I have one issue with std::pair. Well, it might just be a very annoying
+historical accident, but why is there no default template argument for
+the second template argument? This is so annoying when the type in
+question is looong and hard to write (type deduction with auto won't
+help those cases where we use it as a return or argument type).
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change the synopsis in 20.3 [utility] to read:
+
      
+
+
      template <class T1, class T2 = T1> struct pair;
+
      
+
+
      
+Change 20.3.3 [pairs] to read:
+
      
+
+
      namespace std {
+ template <class T1, class T2 = T1>
+ struct pair {
+   typedef T1 first_type;
+   typedef T2 second_type;
+   ...
+
      
+
+
+
      Rationale:
      
+std::pair is a heterogeneous container.
+
+
+
+
+
+
      
+
      841. cstdint.syn inconsistent with C99
      
+
      Section: 18.4.1 [cstdint.syn] Status: NAD Editorial
+ Submitter: Martin Sebor Opened: 2008-05-17  Last modified: 2008-09-17
      
+
      View all other issues in [cstdint.syn].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+   
      
+
+In specifying the names of macros and types defined in
+header <stdint.h>, C99 makes use of the
+symbol N to accommodate unusual platforms with
+word sizes that aren't powers of two. C99
+permits N to take on any positive integer value
+(including, for example, 24).
+
+   
      
+   
      
+
+In  cstdint.syn Header <cstdint>
 synopsis, C++ on the other hand, fixes the value
 of N to 8, 16, 32, and 64, and specifies only
 types with these exact widths. 
 
-   
      
-   
      
-   
      
+   
      
+   
      
+   
      
+
+In addition, paragraph 1 of the same section makes use of a rather
+informal shorthand notation to specify sets of macros. When
+interpreted strictly, the notation specifies macros such
+as INT_8_MIN that are not intended to be specified.
+
+   
      
+
+Finally, the section is missing the usual table of symbols defined
+in that header, making it inconsistent with the rest of the
+specification.
+
+   
      
+ 
+ 
      Proposed resolution:
      
+   
      
+
+I propose to use the same approach in the C++ spec as C99 uses, that
+is, to specify the header synopsis in terms of "exposition only" types
+that make use of the symbol N to denote one or
+more of a theoretically unbounded set of widths.
+
+   
      
+   
      
+
+Further, I propose to add a new table to section listing the symbols
+defined in the header using a more formal notation that avoids
+introducing inconsistencies.
+
+   
      
+   
      
+
+To this effect, in  cstdint.syn
+Header <cstdint> synopsis, replace both the
+synopsis and paragraph 1 with the following text:
+
+   
      
+   
      
+     
      
+       
        
+         
      1. 
+
+In the names defined in the <cstdint> header, the
+symbol N represents a positive decimal integer
+with no leading zeros (e.g., 8 or 24, but not 0, 04, or 048). With the
+exception of exact-width types, macros and types for values
+of N in the set of 8, 16, 32, and 64 are
+required. Exact-width types, and any macros and types for values
+of N other than 8, 16, 32, and 64 are
+optional. However, if an implementation provides integer types with
+widths of 8, 16, 32, or 64 bits, the corresponding exact-width types
+and macros are required.
+
+         
        2. 
+       
      
+     
+     
      namespace std {
+
+   // required types
+
+   // Fastest minimum-width integer types
+   typedef signed integer type   int_fast8_t;
+   typedef signed integer type   int_fast16_t;
+   typedef signed integer type   int_fast32_t;
+   typedef signed integer type   int_fast64_t;
+
+   typedef unsigned integer type uint_fast8_t;
+   typedef unsigned integer type uint_fast16_t;
+   typedef unsigned integer type uint_fast32_t;
+   typedef unsigned integer type uint_fast64_t;
+
+   // Minimum-width integer types
+   typedef signed integer type   int_least8_t;
+   typedef signed integer type   int_least16_t;
+   typedef signed integer type   int_least32_t;
+   typedef signed integer type   int_least64_t;
+
+   typedef unsigned integer type uint_least8_t;
+   typedef unsigned integer type uint_least16_t;
+   typedef unsigned integer type uint_least32_t;
+   typedef unsigned integer type uint_least64_t;
+
+   // Greatest-width integer types
+   typedef signed integer type   intmax_t;
+   typedef unsigned integer type uintmax_t;
+
+   // optionally defined types
+
+   // Exact-width integer types
+   typedef signed integer type   intN_t;
+   typedef unsigned integer type uintN_t;
+
+   // Fastest minimum-width integer types for values
+   // of N other than 8, 16, 32, and 64
+   typedef signed integer type   uint_fastN_t;
+   typedef unsigned integer type uint_fastN_t;
+
+   // Minimum-width integer types for values
+   // of N other than 8, 16, 32, and 64
+   typedef signed integer type   uint_leastN_t;
+   typedef unsigned integer type uint_leastN_t;
+
+   // Integer types capable of holding object pointers
+   typedef signed integer type   intptr_t;
+   typedef signed integer type   intptr_t;
+
+}
      
+   
      
+   
      
+
+[Note to editor: Remove all of the existing paragraph 1 from  cstdint.syn.]
+
+   
      
+   
      
+     Table ??: Header <cstdint> synopsis
+     
+       
+         
+           
+           
+         
+       
+       
+         
+           
+           
+           
+           
+         
+         
+           
+           
+           
+         
+         
+           
+           
+           
+         
+         
+           
+           
+           
+         
+         
+           
+           
+           
+         
+         
+           
+           
+           
+         
+         
+           
+           
+           
+         
+         
+           
+           
+         
+         
+         
+           
+           
+           
+         
+         
+           
+           
+           
+         
+         
+           
+           
+           
+         
+         
+           
+           
+           
+           
+         
+         
+           
+           
+           
+         
+         
+           
+           
+           
+         
+         
+           
+           
+           
+         
+         
+           
+           
+           
+         
+       
+     
      TypeName(s)
      Macros:INTN_MININTN_MAXUINTN_MAX
      INT_FASTN_MININT_FASTN_MAXUINT_FASTN_MAX
      INT_LEASTN_MININT_LEASTN_MAXUINT_LEASTN_MAX
      INTPTR_MININTPTR_MAXUINTPTR_MAX
      INTMAX_MININTMAX_MAXUINTMAX_MAX
      PTRDIFF_MINPTRDIFF_MAXPTRDIFF_MAX
      SIG_ATOMIC_MINSIG_ATOMIC_MAXSIZE_MAX
      WCHAR_MINWCHAR_MAX
      WINT_MINWINT_MAX
      INTN_C()UINTN_C()
      INTMAX_C()UINTMAX_C()
      Types:intN_tuintN_t
      int_fastN_tuint_fastN_t
      int_leastN_tuint_leastN_t
      intptr_tuintptr_t
      intmax_tuintmax_t
      
+   
      
+ 
+
+
+
+
+
      
+
      849. missing type traits to compute root class and derived class of types in a class hierachy
      
+
      Section: 20.6.7 [meta.trans.other] Status: NAD
+ Submitter: Thorsten Ottosen Opened: 2008-06-05  Last modified: 2008-09-16
      
+
      View other active issues in [meta.trans.other].
      
+
      View all other issues in [meta.trans.other].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+The type traits library contains various traits to dealt with
+polymorphic types, e.g. std::has_virtual_destructor, std::is_polymorphic
+and std::is_base_of. However, there is no way to compute the unique
+public base class of a type  if such  one exists.  Such a trait could be
+very useful if one needs to instantiate a specialization made for the
+root class whenever a derived class is passed as parameter. For example,
+imagine that you wanted to specialize std::hash for a class
+hierarchy---instead of specializing each class, you could specialize the
+std::hash<root_class> and provide a partial specialization that worked
+for all derived classes.
+
      
+
+
      
+This ability---to specify operations in terms of their equivalent in the
+root class---can be done with e.g. normal functions, but there is,
+AFAIK, no way to do it for class templates. Being able to access
+compile-time information about the type-hierachy can be very powerful,
+and I therefore also suggest traits that computes the directly derived
+class whenever that is possible.
+
      
+
+
      
+If the computation can not be done, the traits should fall back on an
+identity transformation. I expect this gives the best overall usability.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Add the following to the synopsis in 20.6.2 [meta.type.synop] under "other transformations":
+
      
+
+
      template< class T > struct direct_base_class;
+template< class T > struct direct_derived_class;
+template< class T > struct root_base_class;
+
      
+
+
      
+Add three new entries to table 51 (20.6.7 [meta.trans.other]) with the following content
+
      
+
+
      
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
      TemplateConditionComments
      template< class T > struct direct_base_class;T shall be a complete type.The member typedef type shall equal the accessible unambiguous direct base class of T.
+If no such type exists, the member typedef type shall equal T.
      template< class T > struct direct_derived_class;T shall be a complete type.The member typedef type shall equal the unambiguous type which has T
+as an accessible unambiguous direct base class. If no such type exists, the member typedef
+type shall equal T.
      template< class T > struct root_base_class;T shall be a complete type.The member typedef type shall equal the accessible unambiguous most indirect base class of
+T. If no such type exists, the member typedef type shall equal T.
      
+
      
+
+
+
+
      Rationale:
      
+2008-9-16 San Francisco:  Issue pulled by author prior to being reviewed by the LWG.
+
+
+
+
+
+
      
+
      855. capacity() and reserve() for deque?
      
+
      Section: 23.3.2.2 [deque.capacity] Status: NAD
+ Submitter: Hervé Brönnimann Opened: 2008-06-11  Last modified: 2008-09-22
      
+
      View all other issues in [deque.capacity].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+The main point is that capacity can be viewed as a mechanism to  
+guarantee the validity of iterators when only push_back/pop_back
+operations are used.  For vector, this goes with reallocation.  For  
+deque, this is a bit more subtle:  capacity() of a deque may shrink,  
+whereas that of vector doesn't.   In a circular buffer impl. of the  
+map, as Howard did, there is very similar notion of capacity: as long  
+as size() is less than B * (total size of the map - 2), it is  
+guaranteed that no iterator is invalidated after any number of  
+push_front/back and pop_front/back operations.  But this does not  
+hold for other implementations.
+
      
+
      
+Still, I believe, capacity() can be defined by size() +  how many  
+push_front/back minus pop_front/back that can be performed before  
+terators are invalidated.  In a classical impl., capacity() = size()
++  the min distance to either "physical" end of the deque (i.e.,  
+counting the empty space in the last block plus all the blocks until  
+the end of the map of block pointers).  In Howard's circular buffer  
+impl., capacity() = B * (total size of the map - 2) still works with  
+this definition, even though the guarantee could be made stronger.
+
      
+
      
+A simple picture of a deque:
+
      
+
      A-----|----|-----|---F+|++++|++B--|-----|-----Z
+
      
+
      
+(A,Z mark the beginning/end, | the block boundaries, F=front, B=back,  
+and - are uninitialized, + are initialized)
+In that picture:  capacity = size() + min(dist(A,F),dist(B,Z)) = min 
+(dist(A,B),dist(F,Z)).
+
      
+
      
+Reserve(n) can grow the map of pointers and add possibly a number of  
+empty blocks to it, in order to guarantee that the next n-size()
+push_back/push_front operations will not invalidate iterators, and  
+also will not allocate (i.e. cannot throw).  The second guarantee is  
+not essential and can be left as a QoI.  I know well enough existing  
+implementations of deque (sgi/stl, roguewave, stlport, and  
+dinkumware) to know that either can be implemented with no change to  
+the existing class layout and code, and only a few modifications if  
+blocks are pre-allocated (instead of always allocating a new block,  
+check if the next entry in the map of block pointers is not zero).
+
      
+
      
+Due to the difference with vector, wording is crucial.  Here's a  
+proposed wording to make things concrete;  I tried to be reasonably  
+careful but please double-check me:
+
      
+
+
      [
+San Francisco:
+]
      
+
+
+
      
+
      
+Hans: should the Returns clause for capacity read "1 Returns: A lower
+bound..." rather than "1 Returns: An upper bound..."
+
      
+
      
+Howard: maybe what's needed is capacity_front and capacity_back. In
+fact, I think I implemented a deque that had these members as
+implementation details.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
+
      
+Add new signatures to synopsis in 23.3.2 [deque]:
+
      
+
+
      size_type capacity() const;
+bool reserve(size_type n);
+
      
+
+
      
+Add new signatures to 23.3.2.2 [deque.capacity]:
+
      
+
+
      
+
      size_type capacity() const;
+
      
+
      
+
      
+1 Returns: An upper bound on n + max(n_f - m_f, n_b - m_b)  such  
+that, for any sequence of n_f push_front, m_f pop_front, n_b  
+push_back, and m_b pop_back operations, interleaved in any order,  
+starting with the current deque of size n, the deque does not  
+invalidate any of its iterators except to the erased elements.
+
      
+
      
+2 Remarks:  Unlike a vector's capacity, the capacity of a deque can  
+decrease after a sequence of insertions at both ends, even if none of  
+the operations caused the deque to invalidate any of its iterators  
+except to the erased elements.
+
      
+
      
+
      
+
+
      
+
      bool reserve(size_type n);
+
      
+
      
+
      
+2 Effects: A directive that informs a deque of a planned sequence of  
+push_front, pop_front, push_back, and pop_back operations, so that it  
+can manage iterator invalidation accordingly. After reserve(),  
+capacity() is greater or equal to the argument of reserve if this  
+operation returns true; and equal to the previous value of capacity()
+otherwise.  If an exception is thrown, there are no effects.
+
      
+
      
+3 Returns: true if iterators are invalidated as a result of this  
+operation, and false otherwise.
+
      
+
      
+4 Complexity: It does not change the size of the sequence and takes  
+at most linear time in n.
+
      
+
      
+5 Throws: length_error if n > max_size().
+
      
+
      
+6 Remarks: It is guaranteed that no invalidation takes place during a  
+sequence of insert or erase operations at either end that happens  
+after a call to reserve() except to the erased elements, until the  
+time when an insertion would make max(n_f-m_f, n_b-m_b) larger than  
+capacity(), where n_f is the number of push_front, m_f of pop_front,  
+n_b of push_back, and m_b of pop_back operations since the call to  
+reserve().
+
      
+
      
+7        An implementation is free to pre-allocate buffers so as to  
+offer the additional guarantee that no exception will be thrown  
+during such a sequence other than by the element constructors.
+
      
+
      
+
      
+
+
      
+And 23.3.2.3 [deque.modifiers] para 1, can be enhanced:
+
      
+
+
      
+1 Effects: An insertion in the middle of the deque invalidates all the iterators and references to elements of the
+deque. An insertion at either end of the deque invalidates all the iterators to the deque,
+unless provisions have been made with reserve,
+but has no effect on the validity of references to elements of the deque.
+
      
+
+
+
      Rationale:
      
+Complication outweighs the benefit.
+
+
+
+
+
+
      
+
      862. Impossible complexity for 'includes'
      
+
      Section: 25.5.5.1 [includes] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2008-07-02  Last modified: 2009-07-13
      
+
      View all other issues in [includes].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+In 25.5.5.1 [includes] the complexity is "at most -1 comparisons" if passed
+two empty ranges.  I don't know how to perform a negative number of
+comparisions!
+
      
+
+
      
+This same issue also applies to:
+
      
+
+
        
+
      • set_union
        • 
+
      • set_intersection
        • 
+
      • set_difference
        • 
+
      • set_symmetric_difference
        • 
+
      • merge
        • 
+
      
+
+
      [
+2009-03-30 Beman adds:
+]
      
+
+
+
      
+Suggest NAD. The complexity of empty ranges is -1 in other places in the
+standard. See 25.5.4 [alg.merge] merge and
+inplace_merge, and forward_list merge, for example.
+The time and effort to find and fix all places in the standard where
+empty range[s] result in negative complexity isn't worth the very
+limited benefit.
+
      
+
+
      [
+2009-05-09 Alisdair adds:
+]
      
+
+
+
      
+
      
+I'm not happy with NAD if we can find a simple solution.
+
      
+
      
+How about adding a rider somewhere in clause 17 suggesting that complexities
+that specify a negative number of operations are treated as specifying zero
+operations?  That should generically solve the issue without looking for
+further cases.
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+Pete to provide "straightforward" wording.
+Move to NAD Editorial.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Recommend NAD.
+
      
+
+
+
+
+
+
      
+
      863. What is the state of a stream after close() succeeds
      
+
      Section: 27.9.1 [fstreams] Status: NAD
+ Submitter: Steve Clamage Opened: 2008-07-08  Last modified: 2009-07-13
      
+
      View all other issues in [fstreams].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+Suppose writing to an [o]fstream fails and you later close the stream.
+The overflow() function is called to flush the buffer (if it exists).
+Then the file is unconditionally closed, as if by calling flcose.
+
      
+
      
+If either overflow or fclose fails, close() reports failure, and clearly
+the stream should be in a failed or bad state.
+
      
+
      
+Suppose the buffer is empty or non-existent (so that overflow() does not
+fail), and fclose succeeds. The close() function reports success, but
+what is the state of the stream?
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+Tom's impression is that the issue is about the failbit, etc.
+
      
+
      
+Bill responds that the stream is now closed,
+and any status bits remain unchanged.
+
      
+
      
+See the description of close() in 27.9.1.17 [fstream.members].
+
      
+
      
+We prefer not to add wording to say that nothing changes.
+Move to NAD.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+
      
+
+
+
+
+
+
      
+
      864. Defect in atomic wording
      
+
      Section: 29.6 [atomics.types.operations] Status: NAD Editorial
+ Submitter: Anthony Williams Opened: 2008-07-10  Last modified: 2008-09-17
      
+
      View other active issues in [atomics.types.operations].
      
+
      View all other issues in [atomics.types.operations].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+There's an error in 29.6 [atomics.types.operations]/p9:
+
      
+
+
      
+
      C atomic_load(const volatile A * object);
+C atomic_load_explicit(const volatile A * object, memory_order);
+C A ::load(memory_order order = memory_order_seq_cst) const volatile;
+
      
+
      
+
      
+Requires: The order argument shall not be memory_order_acquire nor
+memory_order_acq_rel.
+
      
+
      
+
      
+
+
      
+I believe that this should state
+
      
+
      
+shall not be memory_order_release.
+
      
+
+
      
+There's also an error in 29.6 [atomics.types.operations]/p17:
+
      
+
+
      
+... When only one memory_order argument is supplied, the value of success
+is order, and
+the value of failure is order except that a value of
+memory_order_acq_rel shall be replaced by the value
+memory_order_require ...
+
      
+
      
+I believe this should state
+
      
+
      
+shall be replaced by the value memory_order_acquire ...
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 29.6 [atomics.types.operations]/p9:
+
      
+
+
      
+
      C atomic_load(const volatile A * object);
+C atomic_load_explicit(const volatile A * object, memory_order);
+C A ::load(memory_order order = memory_order_seq_cst) const volatile;
+
      
+
      
+
      
+Requires: The order argument shall not be memory_order_acquire
+memory_order_release nor memory_order_acq_rel.
+
      
+
      
+
      
+
+
      
+Change 29.6 [atomics.types.operations]/p17:
+
      
+
+
      
+... When only one memory_order argument is supplied, the value of success
+is order, and
+the value of failure is order except that a value of
+memory_order_acq_rel shall be replaced by the value
+memory_order_require memory_order_acquire ...
+
      
+
+
+
+
      Rationale:
      
+Already fixed by the time the LWG processed it.
+
+
+
+
+
+
      
+
      867. Valarray and value-initialization
      
+
      Section: 26.6.2.1 [valarray.cons] Status: NAD Editorial
+ Submitter: Alberto Ganesh Barbati Opened: 2008-07-20  Last modified: 2009-07-13
      
+
      View all other issues in [valarray.cons].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+From 26.6.2.1 [valarray.cons], paragraph 2:
+
      
+
+
      explicit  valarray(size_t);
+
      
+
      
+The array created by this constructor has a length equal to the value of the argument. The elements
+of the array are constructed using the default constructor for the instantiating type T.
+
      
+
      
+
+
      
+The problem is that the most obvious Ts for valarray are float
+and double, they don't have a default constructor. I guess the intent is to value-initialize
+the elements, so I suggest replacing:
+
      
+
+
      
+The elements of the array are constructed using the default constructor for the instantiating type T.
+
      
+
      
+with
+
      
+
      
+The elements of the array are value-initialized.
+
      
+
+
      
+There is another reference to the default constructor of T in the non-normative note in paragraph 9.
+That reference should also be replaced. (The normative wording in paragraph 8 refers to T()
+and so it doesn't need changes).
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to NAD Editorial.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 26.6.2.1 [valarray.cons], paragraph 2:
+
      
+
+
      
+
      explicit  valarray(size_t);
+
      
+
      
+The array created by this constructor has a length equal to the value of the argument. The elements
+of the array are constructed using the default constructor for the instantiating type T
+value-initialized (8.5 [dcl.init]).
+
      
+
      
+
+
      
+Change 26.6.2.7 [valarray.members], paragraph 9:
+
      
+
+
      
+[Example: If the argument has the value -2, the first two elements of the result will be constructed using the 
+default constructor
+value-initialized (8.5 [dcl.init]);
+the third element of the result will be assigned the value of the first element of the argument; etc. -- end example]
+
      
+
+
+
+
+
+
+
      
+
      873. signed integral type and unsigned integral type are not clearly defined
      
+
      Section: 3.9.1 [basic.fundamental] Status: NAD Editorial
+ Submitter: Travis Vitek Opened: 2008-06-30  Last modified: 2009-07-17
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+    
      
+      Neither the term "signed integral type" nor the term "unsigned
+      integral type" is defined in the core language section of the
+      standard, therefore the library section should avoid its use.  The
+      terms signed integer type and unsigned integer type are
+      indeed defined (in 3.9.1 [basic.fundamental]), thus the usages should be
+      replaced accordingly.
+    
      
+
+    
      
+      Note that the key issue here is that "signed" + "integral type" !=
+      "signed integral type".
+      
+      The types bool, char, char16_t,
+      char32_t and wchar_t are all listed as
+      integral types, but are neither of signed integer type or
+      unsigned integer type. According to 3.9 [basic.types] p7, a synonym for
+      integral type is integer type.
+      
+      Given this, one may choose to assume that an integral type that
+      can represent values less than zero is a signed integral type.
+      Unfortunately this can cause ambiguities.
+      
+      As an example, if T is unsigned char, the
+      expression make_signed<T>::type, is supposed to
+      name a signed integral type. There are potentially two types that
+      satisfy this requirement, namely signed char and
+      char (assuming CHAR_MIN < 0).
+    
      
+
+
      [
+San Francisco:
+]
      
+
+
+
      
+Plum, Sebor to review.
+
      
+
+
      [
+Post Summit Daniel adds:
+]
      
+
+
+
      
+The proposed resolution needs to be "conceptualized". Currently we have
+in 14.10.4 [concept.support] only concept IntegralType
+for all "integral types", thus indeed the current Container
+concept and Iterator concepts are sufficiently satisfied with "integral
+types". If the changes are applied, we might ask core for concept
+BilateralIntegerType and add proper restrictions to the library
+concepts.
+
      
+
+  
+
+  
      Proposed resolution:
      
+    
      
+      I propose to use the terms "signed integer type" and "unsigned integer
+      type" in place of "signed integral type" and "unsigned integral type"
+      to eliminate such ambiguities.
+    
      
+    
+    
      
+      The proposed change makes it absolutely clear that the difference
+      between two pointers cannot be char or wchar_t,
+      but could be any of the signed integer types.
+      5.7 [expr.add] paragraph 6...
+    
      
+    
      
+      
      
+        
        
+          
      1. 
+            When two pointers to elements of the same array object are
+            subtracted, the result is the difference of the subscripts of
+            the two array elements. The type of the result is an
+            implementation-defined signed integral
+            typesigned integer type; this type shall be the
+            same type that is defined as std::ptrdiff_t in the
+            <cstdint> header (18.1)...
+          
        2. 
+        
      
+      
+    
      
+
+    
      
+      The proposed change makes it clear that X::size_type and
+      X::difference_type cannot be char or
+      wchar_t, but could be one of the signed or unsigned integer
+      types as appropriate.
+      X [allocator.requirements] table 40...
+    
      
+    
      
+      Table 40: Allocator requirements
+      
+        
+          
+            
+            
+            
+          
+        
+        
+          
+            
+            
+            
+          
+          
+            
+            
+            
+          
+        
+      
      expressionreturn typeassertion/note/pre/post-condition
      X::size_type
+              unsigned integral type
+              unsigned integer type
+            a type that can represent the size of the largest object in
+            the allocation model.
      X::difference_type
+              signed integral type
+              signed integer type
+            a type that can represent the difference between any two
+            pointers in the allocation model.
      
+    
      
+
+    
      
+      The proposed change makes it clear that make_signed<T>::type
+      must be one of the signed integer types as defined in 3.9.1. Ditto for
+      make_unsigned<T>type and unsigned integer types.
+      20.6.6.3 [meta.trans.sign] table 48...
+    
      
+    
      
+      Table 48: Sign modifications
+      
+        
+          
+            
+            
+          
+        
+        
+          
+            
+            
+          
+          
+            
+            
+          
+        
+      
      TemplateComments
      
+              template <class T> struct make_signed;
+            
+              If T names a (possibly cv-qualified) signed
+              integral typesigned integer type (3.9.1) then
+              the member typedef type shall name the type
+              T; otherwise, if T names a (possibly
+              cv-qualified) unsigned integral typeunsigned
+              integer type then type shall name the
+              corresponding signed integral typesigned
+              integer type, with the same cv-qualifiers as
+              T; otherwise, type shall name the
+              signed integral typesigned integer type
+              with the smallest rank (4.13) for which sizeof(T) ==
+              sizeof(type), with the same cv-qualifiers as
+              T.
+
+              Requires: T shall be a (possibly
+              cv-qualified) integral type or enumeration but not a
+              bool type.
+            
      
+              template <class T> struct make_unsigned;
+            
+              If T names a (possibly cv-qualified)
+              unsigned integral typeunsigned integer
+              type (3.9.1) then the member typedef type
+              shall name the type T; otherwise, if
+              T names a (possibly cv-qualified) signed
+              integral typesigned integer type then
+              type shall name the corresponding unsigned
+              integral typeunsigned integer type, with the
+              same cv-qualifiers as T; otherwise,
+              type shall name the unsigned integral
+              typeunsigned integer type with the smallest
+              rank (4.13) for which sizeof(T) == sizeof(type),
+              with the same cv-qualifiers as T.
+
+              Requires: T shall be a (possibly
+              cv-qualified) integral type or enumeration but not a
+              bool type.
+            
      
+    
      
+
+
+    
      
+      Note: I believe that the basefield values should probably be
+      prefixed with ios_base:: as they are in 22.4.2.2.2 [facet.num.put.virtuals]
+
+      The listed virtuals are all overloaded on signed and unsigned integer
+      types, the new wording just maintains consistency.
+
+      22.4.2.1.2 [facet.num.get.virtuals] table 78...
+    
      
+    
      
+      Table 78: Integer Conversions
+      
+        
+          
+            
+            
+          
+        
+        
+          
+            
+            
+          
+          
+            
+            
+          
+          
+            
+            
+          
+          
+            
+            
+          
+          
+            
+            
+          
+        
+      
      Statestdio equivalent
      basefield == oct%o
      basefield == hex%X
      basefield == 0%i
      signed integral typesigned integer
+            type%d
      unsigned integral typeunsigned integer
+            type%u
      
+    
      
+
+    
+    
+    
      
+      Rationale is same as above.
+      22.4.2.2.2 [facet.num.put.virtuals] table 80...
+    
      
+    
      
+      Table 80: Integer Conversions
+      
+        
+          
+            
+            
+          
+        
+        
+          
+            
+            
+          
+          
+            
+            
+          
+          
+            
+            
+          
+          
+            
+            
+          
+          
+            
+            
+          
+          
+            
+            
+          
+        
+      
      Statestdio equivalent
      basefield == ios_base::oct%o
      (basefield == ios_base::hex) &&
+            !uppercase%x
      (basefield == ios_base::hex)%X
      basefield == 0%i
      for a signed integral typesigned integer
+            type%d
      for a unsigned integral typeunsigned integer
+            type%u
      
+    
      
+
+    
+    
      
+      23.2 [container.requirements] table 80...
+    
      
+    
      
+      Table 89: Container requirements
+      
+        
+          
+            
+            
+            
+            
+            
+          
+        
+        
+          
+            
+            
+            
+            
+            
+          
+          
+            
+            
+            
+            
+            
+          
+        
+      
      expressionreturn typeoperational semanticsassertion/note/pre/post-conditioncomplexity
      X::difference_typesigned integral typesigned integer type is identical to the difference type of X::iterator
+            and X::const_iteratorcompile time
      X::size_typeunsigned integral typeunsigned integer type size_type can represent any non-negative value of
+            difference_typecompile time
      
+    
      
+
+    
      
+      24.2 [iterator.concepts] paragraph 1...
+    
      
+    
      
+      Iterators are a generalization of pointers that allow a C++ program to
+      work with different data structures (containers) in a uniform manner.
+      To be able to construct template algorithms that work correctly and
+      efficiently on different types of data structures, the library
+      formalizes not just the interfaces but also the semantics and
+      complexity assumptions of iterators. All input iterators
+      i support the expression *i, resulting in a
+      value of some class, enumeration, or built-in type T,
+      called the value type of the iterator. All output iterators
+      support the expression *i = o where o is a
+      value of some type that is in the set of types that are
+      writable to the particular iterator type of i. All
+      iterators i for which the expression (*i).m
+      is well-defined, support the expression i->m with the
+      same semantics as (*i).m. For every iterator type
+      X for which equality is defined, there is a corresponding
+      signed integral type signed integer type called
+      the difference type of the iterator.
+    
      
+    
+    
      
+      I'm a little unsure of this change. Previously this paragraph would
+      allow instantiations of linear_congruential_engine on
+      char, wchar_t, bool, and other types. The
+      new wording prohibits this.
+      26.5.3.1 [rand.eng.lcong] paragraph 2...
+    
      
+    
      
+      The template parameter UIntType shall denote an
+      unsigned integral typeunsigned integer type
+      large enough to store values as large as m - 1. If the
+      template parameter m is 0, the modulus m
+      used throughout this section 26.4.3.1 is
+      numeric_limits<result_type>::max() plus 1.  [Note:
+      The result need not be representable as a value of type
+      result_type. --end note] Otherwise, the following
+      relations shall hold: a < m and c <
+      m.
+    
      
+    
+    
      
+      Same rationale as the previous change.
+      X [rand.adapt.xor] paragraph 6...
+    
      
+    
      
+      Both Engine1::result_type and
+      Engine2::result_type shall denote (possibly different)
+      unsigned integral typesunsigned integer types.
+      The member result_type shall denote either the type
+      Engine1::result_type or the type Engine2::result_type,
+      whichever provides the most storage according to clause 3.9.1.
+    
      
+    
+    
      
+      26.5.7.1 [rand.util.seedseq] paragraph 7...
+    
      
+    
      
+      Requires:RandomAccessIterator shall meet the
+      requirements of a random access iterator (24.1.5) such that
+      iterator_traits<RandomAccessIterator>::value_type
+      shall denote an unsigned integral typeunsigned integer
+      type capable of accomodating 32-bit quantities.  
+    
      
+
+    
      
+      By making this change, integral types that happen to have a signed
+      representation, but are not signed integer types, would no longer be
+      required to use a two's complement representation. This may go against
+      the original intent, and should be reviewed.
+      29.6 [atomics.types.operations] paragraph 24...
+    
      
+    
      
+      Remark: For signed integral typessigned integer
+      types, arithmetic is defined using two's complement
+      representation. There are no undefined results. For address types, the
+      result may be an undefined address, but the operations otherwise have
+      no undefined behavior.
+    
      
+    
+  
+
+
+
+
+
      
+
      874. Missing initializer_list constructor for discrete_distribution
      
+
      Section: 26.5.8.5.1 [rand.dist.samp.discrete] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2008-08-22  Last modified: 2009-03-09
      
+
      View all other issues in [rand.dist.samp.discrete].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+During the Sophia Antipolis meeting it was decided to separate from 793 a
+subrequest that adds initializer list support to
+discrete_distribution, specifically,
+the issue proposed to add a c'tor taking a initializer_list<double>.
+
      
+
+
+
+
      Proposed resolution:
      
+
        
+
      1. 
+
        
+In 26.5.8.5.1 [rand.dist.samp.discrete]/1, class discrete_distribution,
+just before the member declaration
+
        
+
+
        explicit discrete_distribution(const param_type& parm);
+
        
+
+
        
+insert
+
        
+
+
        discrete_distribution(initializer_list<double> wl);
+
        
+
        2. 
+
+
      2. 
+
        
+Between p.4 and p.5 of the same section insert a new
+paragraph as part of the new member description:
+
        
+
+
        discrete_distribution(initializer_list<double> wl);
+
        
+
+
        
+Effects: Same as discrete_distribution(wl.begin(), wl.end()).
+
        
+
        
+
        3. 
+
      
+
+
+
      Rationale:
      
+Addressed by
+N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
+
+
+
+
+
+
      
+
      875. Missing initializer_list constructor for piecewise_constant_distribution
      
+
      Section: 26.5.8.5.2 [rand.dist.samp.pconst] Status: NAD Editorial
+ Submitter: Daniel Krügler Opened: 2008-08-22  Last modified: 2009-03-09
      
+
      View all other issues in [rand.dist.samp.pconst].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+During the Sophia Antipolis meeting it was decided to separate from
+794 a subrequest that adds initializer list support to
+piecewise_constant_distribution, specifically, the issue proposed
+to add a c'tor taking a initializer_list<double> and a Callable to evaluate
+weight values. For consistency with the remainder of this class and
+the remainder of the initializer_list-aware library the author decided to
+change the list argument type to the template parameter RealType
+instead. For the reasoning to use Func instead of Func&& as c'tor
+function argument see issue 793.
+
      
+
+
+
      Proposed resolution:
      
+
      Non-concept version of the proposed resolution
      
+
+
        
+
      1. 
+
        
+In 26.5.8.5.2 [rand.dist.samp.pconst]/1, class piecewise_constant_distribution,
+just before the member declaration
+
        
+
+
        explicit piecewise_constant_distribution(const param_type& parm);
+
        
+
+
        
+insert
+
        
+
+
        template<typename Func>
+piecewise_constant_distribution(initializer_list<RealType> bl, Func fw);
+
        
+
        2. 
+
+
      2. 
+
        
+Between p.4 and p.5 of the same section insert a series of
+new paragraphs nominated below as [p5_1], [p5_2], and [p5_3]
+as part of the new member description:
+
        
+
+
        template<typename Func>
+piecewise_constant_distribution(initializer_list<RealType> bl, Func fw);
+
        
+
+
        
+
+
        
+[p5_1] Complexity: Exactly nf = max(bl.size(), 1) - 1 invocations of fw.
+
        
+
+
        
+[p5_2] Requires:
+
        
+
+
          
+
        1. 
+fw shall be callable with one argument of type RealType, and shall
+   return values of a type convertible to double;
+
          2. 
+
        2. 
+The relation 0 < S = w0+. . .+wn-1 shall hold. 
+For all sampled values xk defined below, fw(xk) shall return a weight
+   value wk that is non-negative, non-NaN, and non-infinity;
+
          3. 
+
        3. 
+If nf > 0 let bk = *(bl.begin() + k), k = 0, . . . , bl.size()-1 and the
+following relations shall hold for k = 0, . . . , nf-1: bk < bk+1.
+
          4. 
+
        
+
+
        
+[p5_3] Effects:
+
        
+
+
          
+
        1. 
+
          If nf == 0,
          
+
            
+
          1. 
+lets the sequence w have length n = 1 and consist of the single
+     value w0 = 1, and
+
            2. 
+
          2. 
+lets the sequence b have length n+1 with b0 = 0 and b1 = 1.
+
            3. 
+
          
+
          2. 
+
+
        2. 
+
          Otherwise,
          
+
            
+
          1. 
+sets n = nf, and [bl.begin(), bl.end()) shall form the sequence b of
+length n+1, and
+
            2. 
+
          2. 
+
            lets the sequences w have length n and for each k = 0, . . . ,n-1,
+     calculates:
            
+
            xk = 0.5*(bk+1 + bk)
+wk = fw(xk)
+
            
+
            3. 
+
          
+
          3. 
+
+
        3. 
+
          
+Constructs a piecewise_constant_distribution object with
+the above computed sequence b as the interval boundaries
+and with the probability densities:
+
          
+
          ρk = wk/(S * (bk+1 - bk)) for k = 0, . . . , n-1.
+
          
+
+
          4. 
+
        
+
+
        
+
        
+
        3. 
+
      
+
+
      Concept version of the proposed resolution
      
+
+
        
+
      1. 
+
        
+In 26.5.8.5.2 [rand.dist.samp.pconst]/1, class piecewise_constant_distribution,
+just before the member declaration
+
        
+
+
        explicit piecewise_constant_distribution(const param_type& parm);
+
        
+
+
        
+insert
+
        
+
+
        template<Callable<auto, RealType> Func>
+ requires Convertible<Func::result_type, double>
+piecewise_constant_distribution(initializer_list<RealType> bl, Func fw);
+
        
+
        2. 
+
+
      2. 
+
        
+Between p.4 and p.5 of the same section insert a series of
+new paragraphs nominated below as [p5_1], [p5_2], and [p5_3]
+as part of the new member description:
+
        
+
+
        template<Callable<auto, RealType> Func>
+ requires Convertible<Func::result_type, double>
+piecewise_constant_distribution(initializer_list<RealType> bl, Func fw);
+
        
+
+
        
+
+
        
+[p5_1] Complexity: Exactly nf = max(bl.size(), 1) - 1 invocations of fw.
+
        
+
+
        
+[p5_2] Requires:
+
        
+
+
          
+
        1. 
+The relation 0 < S = w0+. . .+wn-1 shall hold. 
+For all sampled values xk defined below, fw(xk) shall return a weight
+   value wk that is non-negative, non-NaN, and non-infinity;
+
          2. 
+
        2. 
+If nf > 0 let bk = *(bl.begin() + k), k = 0, . . . , bl.size()-1 and the
+following relations shall hold for k = 0, . . . , nf-1: bk < bk+1.
+
          3. 
+
        
+
+
        
+[p5_3] Effects:
+
        
+
+
          
+
        1. 
+
          If nf == 0,
          
+
            
+
          1. 
+lets the sequence w have length n = 1 and consist of the single
+     value w0 = 1, and
+
            2. 
+
          2. 
+lets the sequence b have length n+1 with b0 = 0 and b1 = 1.
+
            3. 
+
          
+
          2. 
+
+
        2. 
+
          Otherwise,
          
+
            
+
          1. 
+sets n = nf, and [bl.begin(), bl.end()) shall form the sequence b of
+length n+1, and
+
            2. 
+
          2. 
+
            lets the sequences w have length n and for each k = 0, . . . ,n-1,
+     calculates:
            
+
            xk = 0.5*(bk+1 + bk)
+wk = fw(xk)
+
            
+
            3. 
+
          
+
          3. 
+
+
        3. 
+
          
+Constructs a piecewise_constant_distribution object with
+the above computed sequence b as the interval boundaries
+and with the probability densities:
+
          
+
          ρk = wk/(S * (bk+1 - bk)) for k = 0, . . . , n-1.
+
          
+
+
          4. 
+
        
+
+
        
+
        
+
        3. 
+
      
+
+
+
+
      Rationale:
      
+Addressed by
+N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
+
+
+
+
+
+
      
+
      877. to throw() or to Throw: Nothing.
      
+
      Section: 17 [library] Status: NAD Future
+ Submitter: Martin Sebor Opened: 2008-08-23  Last modified: 2009-07-17
      
+
      View other active issues in [library].
      
+
      View all other issues in [library].
      
+
      View all issues with NAD Future status.
      
+
      Discussion:
      
+       
      
+
+Recent changes to
+the working
+draft have introduced a gratuitous inconsistency with the C++ 2003
+version of the specification with respect to exception guarantees
+provided by standard functions. While the C++ 2003 standard
+consistenly uses the empty exception specification, throw(),
+to declare functions that are guaranteed not to throw exceptions, the
+current working draft contains a number of "Throws: Nothing."
+clause to specify essentially the same requirement. The difference
+between the two approaches is that the former specifies the behavior
+of programs that violate the requirement (std::unexpected()
+is called) while the latter leaves the behavior undefined.
+
+       
      
+       
      
+
+A survey of the working draft reveals that there are a total of 209
+occurrences of throw() in the library portion of the spec,
+the majority in clause 18, a couple (literally) in 19, a handful in
+20, a bunch in 22, four in 24, one in 27, and about a dozen in D.9.
+
+       
      
+       
      
+
+There are also 203 occurrences of "Throws: Nothing." scattered
+throughout the spec.
+
+       
      
+       
      
+
+While sometimes there are good reasons to use the "Throws:
+Nothing."  approach rather than making use of throw(), these
+reasons do not apply in most of the cases where this new clause has
+been introduced and the empty exception specification would be a
+better approach.
+
+       
      
+       
      
+
+First, functions declared with the empty exception specification
+permit compilers to generate better code for calls to such
+functions. In some cases, the compiler might even be able to eliminate
+whole chunks of user-written code when instantiating a generic
+template on a type whose operations invoked from the template
+specialization are known not to throw. The prototypical example are
+the std::uninitialized_copy()
+and std::uninitialized_fill() algorithms where the
+entire catch(...) block can be optimized away.
+
+       
      
+       
      
+
+For example, given the following definition of
+the std::uninitialized_copy function template and a
+user-defined type SomeType:
+
+       
      
+       
      
+           
      template <class InputIterator, class ForwardIterator>
+ForwardIterator
+uninitialized_copy (InputIterator first, InputIterator last, ForwardIterator res)
+{
+   typedef iterator_traits<ForwardIterator>::value_type ValueType;
+
+   ForwardIterator start = res;
+
+   try {
+       for (; first != last; ++first, ++res)
+           ::new (&*res) ValueType (*first);
+   }
+   catch (...) {
+       for (; start != res; --start)
+           (&*start)->~ValueType ();
+       throw;
+   }
+   return res;
+}
+
+struct SomeType {
+   SomeType (const SomeType&) throw ();
+}
      
+       
      
+       
      
+
+compilers are able to emit the following efficient specialization
+of std::uninitialized_copy<const SomeType*, SomeType*>
+(note that the catch block has been optimized away):
+
+       
      
+       
      
+           
      template <> SomeType*
+uninitialized_copy (const SomeType *first, const SomeType *last, SomeType *res)
+{
+   for (; first != last; ++first, ++res)
+       ::new (res) SomeType (*first);
+
+   return res;
+}
      
+       
      
+       
      
+
+Another general example is default constructors which, when decorated
+with throw(), allow the compiler to eliminate the
+implicit try and catch blocks that it otherwise must
+emit around each the invocation of the constructor
+in new-expressions.
+
+       
      
+       
      
+
+For example, given the following definitions of
+class MayThrow and WontThrow and the two
+statements below:
+
+       
      
+       
      
+           
      struct MayThrow {
+   MayThrow ();
+};
+
+struct WontThrow {
+   WontThrow () throw ();
+};
+
+MayThrow  *a = new MayThrow [N];
+WontThrow *b = new WontThrow [N];
      
+
+       
      
+       
      
+
+the compiler generates the following code for the first statement:
+
+       
      
+       
      
+           
      MayThrow *a;
+{
+   MayThrow *first = operator new[] (N * sizeof (*a));
+   MayThrow *last  = first + N;
+   MayThrow *next  = first;
+   try {
+       for ( ; next != last; ++next)
+           new (next) MayThrow;
+   }
+   catch (...) {
+       for ( ; first != first; --next)
+           next->~MayThrow ();
+       operator delete[] (first);
+       throw;
+   }
+   a = first;
+}
      
+       
      
+       
      
+
+but it is can generate much more compact code for the second statement:
+
+       
      
+       
      
+           
      WontThrow *b    = operator new[] (N * sizeof (*b));
+WontThrow *last = b + N;
+for (WontThrow *next = b; next != last; ++next)
+   new (next) WontThrow;
+
      
+       
      
+       
      
+
+Second, in order for users to get the maximum benefit out of the new
+std::has_nothrow_xxx traits when using standard library types
+it will be important for implementations to decorate all non throwing
+copy constructors and assignment operators with throw(). Note
+that while an optimizer may be able to tell whether a function without
+an explicit exception specification can throw or not based on its
+definition, it can only do so when it can see the source code of the
+definition. When it can't it must assume that the function may
+throw. To prevent violating the One Definition Rule,
+the std::has_nothrow_xxx trait must return the most
+pessimistic guess across all translation units in the program, meaning
+that std::has_nothrow_xxx<T>::value must evaluate to
+false for any T whose xxx
+(where xxx is default or copy ctor, or assignment operator)
+is defined out-of-line.
+
+       
      
+       
      
+
+Counterarguments:
+
+       
      
+       
      
+
+During the discussion of this issue
+on c++std-lib@accu.org
+(starting with post c++std-lib-21950) the following arguments
+in favor of the "Throws: Nothing." style have been made.
+
+       
      
+       
      
+         
        
+           
      1. 
+
+Decorating functions that cannot throw with the empty exception
+specification can cause the compiler to generate suboptimal code for
+the implementation of the function when it calls other functions that
+aren't known to the compiler not to throw (i.e., that aren't decorated
+with throw() even if they don't actually throw). This is a
+common situation when the called function is a C or POSIX function.
+
+           
        2. 
+           
      2. 
+
+Alternate, proprietary mechanisms exist (such as
+GCC __attribute__((nothrow))
+or Visual
+C++ __declspec(nothrow))
+that let implementers mark up non-throwing functions, often without
+the penalty mentioned in (1) above. The C++ standard shouldn't
+preclude the use of these potentially more efficient mechanisms.
+
+           
        3. 
+           
      3. 
+
+There are functions, especially function templates, that invoke
+user-defined functions that may or may not be
+declared throw(). Declaring such functions with the empty
+exception specification will cause compilers to generate suboptimal
+code when the user-defined function isn't also declared not to throw.
+
+           
        4. 
+        
      
+       
+       
      
+
+The answer to point (1) above is that implementers can (and some have)
+declare functions with throw() to indicate to the compiler
+that calls to the function can safely be assumed not to throw in order
+to allow it to generate efficient code at the call site without also
+having to define the functions the same way and causing the compiler
+to generate suboptimal code for the function definition. That is, the
+function is declared with throw() in a header but it's
+defined without it in the source file. The throw()
+declaration is suppressed when compiling the definition to avoid
+compiler errors. This technique, while strictly speaking no permitted
+by the language, is safe and has been employed in practice. For
+example, the GNU C library takes this approach. Microsoft Visual C++
+takes a similar approach by simply assuming that no function with C
+language linkage can throw an exception unless it's explicitly
+declared to do so using the language extension throw(...).
+
+       
      
+       
      
+
+Our answer to point (2) above is that there is no existing practice
+where C++ Standard Library implementers have opted to make use of the
+proprietary mechanisms to declare functions that don't throw. The
+language provides a mechanism specifically designed for this
+purpose. Avoiding its use in the specification itself in favor of
+proprietary mechanisms defeats the purpose of the feature. In
+addition, making use of the empty exception specification
+inconsistently, in some areas of the standard, while conspicuously
+avoiding it and making use of the "Throws: Nothing." form in
+others is confusing to users.
+
+       
      
+       
      
+
+The answer to point (3) is simply to exercise caution when declaring
+functions and especially function templates with the empty exception
+specification. Functions that required not to throw but that may call
+back into user code are poor candidates for the empty exception
+specification and should instead be specified using "Throws:
+Nothing." clause.
+
+      
      
+
+
      [
+2009-07 Frankfurt
+]
      
+
+
+
      
+
      
+We need someone to do an extensive review.
+
      
+
      
+NAD Future.
+
      
+
      
+
+   
+   
      Proposed resolution:
      
+       
      
+
+We propose two possible solutions. Our recommendation is to adopt
+Option 1 below.
+
+       
      
+       
      
+
+Option 1:
+
+       
      
+       
      
+
+Except for functions or function templates that make calls back to
+user-defined functions that may not be declared throw()
+replace all occurrences of the "Throws: Nothing." clause with
+the empty exception specification. Functions that are required not to
+throw but that make calls back to user code should be specified to
+"Throw: Nothing."
+
+       
      
+       
      
+
+Option 2:
+
+       
      
+       
      
+
+For consistency, replace all occurrences of the empty exception
+specification with a "Throws: Nothing." clause.
+
+       
      
+   
+
+
+
+
      
+
      884. shared_ptr swap
      
+
      Section: 20.8.10.2.4 [util.smartptr.shared.mod] Status: NAD Editorial
+ Submitter: Jonathan Wakely Opened: 2008-09-15  Last modified: 2009-07-13
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      #include <memory>
+#include <cassert>
+
+struct A { };
+struct B : A { };
+
+int main()
+{
+    std::shared_ptr<A> pa(new A);
+    std::shared_ptr<B> pb(new B);
+    std::swap<A>(pa, pb);  // N.B. no argument deduction
+    assert( pa.get() == pb.get() );
+    return 0;
+}
+
      
+
+
      
+Is this behaviour correct (I believe it is) and if so, is it
+unavoidable, or not worth worrying about?
+
      
+
+
      
+This calls the lvalue/rvalue swap overload for shared_ptr:
+
      
+
+
      template<class T> void swap( shared_ptr<T> & a, shared_ptr<T> && b );
+
      
+
+
      
+silently converting the second argument from shared_ptr<B> to
+shared_ptr<A> and binding the rvalue ref to the produced temporary.
+
      
+
+
      
+This is not, in my opinion, a shared_ptr problem; it is a general issue
+with the rvalue swap overloads. Do we want to prevent this code from
+compiling? If so, how?
+
      
+
+
      
+Perhaps we should limit rvalue args to swap to those types that would
+benefit from the "swap trick".  Or, since we now have shrink_to_fit(), just
+eliminate the rvalue swap overloads altogether.  The original motivation
+was:
+
      
+
+
      vector<A> v = ...;
+...
+swap(v, vector<A>(v));
+
      
+
+N1690.
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to NAD Editorial.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Recommend NAD Editorial, fixed by
+N2844.
+
      
+
+
+
+
+
+
      
+
      892. Forward_list issues...
      
+
      Section: 23.3.3.5 [forwardlist.ops] Status: NAD Editorial
+ Submitter: Ed Smith-Rowland Opened: 2008-09-15  Last modified: 2009-03-09
      
+
      View other active issues in [forwardlist.ops].
      
+
      View all other issues in [forwardlist.ops].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+I was looking at the latest draft on forward_list.  Especially the splice methods.
+
      
+
      
+The first one splices a whole list after a given iterator in this.  The name is splice_after.
+I think in 23.3.3.5 [forwardlist.ops] paragraph 40
+change:
+
      
+
      
+Effect: Insert the contents of x before after position, ...
+
      
+
+
      
+A deeper issue involves the complexity.  forward_list has no size and we
+don't know when we've reached the end except to walk up to it.  To
+splice we would need to hook the end of the source list to the item
+after position in this list.  This would involve walking length of the
+source list until we got to the last dereference-able element in source.
+There's no way we could do this in O(1) unless we stored a bogus end in
+forward_list.
+
      
+
      
+OTOH, the last version of splice_after with iterator ranges we could do
+in O(1) because we know how to hook the end of the source range to ...
+
      
+
      
+Unless I'm misconceiving the whole thing.  Which is possible.  I'll look at it again.
+
      
+
      
+I'm pretty sure about the first part though.
+
      
+
+
      [
+San Francisco:
+]
      
+
+
+
      
+
      
+This issue is more complicated than it looks.
+
      
+
      
+paragraph 47: replace each (first, last) with (first, last]
+
      
+
      
+add a statement after paragraph 48 that complexity is O(1)
+
      
+
      
+remove the complexity statement from the first overload of splice_after
+
      
+
      
+We may have the same problems with other modifiers, like erase_after.
+Should it require that all iterators in the range (position, last] be
+dereferenceable?
+
      
+
      
+We do, however, like the proposed changes and consider them Editorial.
+Move to NAD Editorial, Pending. Howard to open a new issue to handle the
+problems with the complexity requirements.
+
      
+
      
+Opened 897.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+In 23.3.3.5 [forwardlist.ops] paragraph 40
+change:
+
      
+
      
+Effect: Insert the contents of x before after position, ...
+
      
+
+
+
+
+
+
      
+
      895. "Requires:" on std::string::at et al
      
+
      Section: 17.5.1.4 [structure.specifications] Status: Dup
+ Submitter: James Dennett Opened: 2008-09-16  Last modified: 2009-07-17
      
+
      View all other issues in [structure.specifications].
      
+
      View all issues with Dup status.
      
+
      Duplicate of: 625
      
+
      Discussion:
      
+
      
+Per discussion, we need an issue open to cover looking at "Requires"
+clauses which are not constraints on user code, such as that on
+std::basic_string::at.
+
      
+
+
      [
+2009-07 Frankfurt
+]
      
+
+
+
      
+ Alan to address in paper.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+
      
+
+
+
+
+
+
      
+
      901. insert iterators can move from lvalues
      
+
      Section: 24.7.5 [insert.iterator] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2008-09-24  Last modified: 2009-07-13
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      Addresses UK 282
      
+
+
      
+The requires clause on the const T & overloads in
+back_insert_iterator/front_insert_iterator/insert_iterator mean that the
+assignment operator will implicitly move from lvalues of a move-only type.
+
      
+
      
+Suggested resolutions are:
+
      
+
        
+
      1. 
+Add another overload with a negative constraint on copy-constructible
+and flag it "= delete".
+
        2. 
+
      2. 
+Drop the copy-constructible overload entirely and rely on perfect
+forwarding to catch move issues one level deeper.
+
        3. 
+
      3. 
+This is a fundamental problem in move-syntax that relies on the
+presence of two overloads, and we need to look more deeply into this
+area as a whole - do not solve this issue in isolation.
+
        4. 
+
      
+
+
      [
+Post Summit, Alisdair adds:
+]
      
+
+
+
      
+
      
+Both comment and issue have been resolved by the adoption of
+N2844
+(rvalue references safety fix) at the last meeting.
+
      
+
+
      
+Suggest resolve as NAD Editorial with a reference to the paper.
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree that this has been resolved in the latest Working Draft.
+Move to NAD.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Recommend NAD, addressed by N2844.
+
      
+
+
+
+
+
+
      
+
      902. Regular is the wrong concept to constrain numeric_limits
      
+
      Section: 18.3.1 [limits] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2008-09-24  Last modified: 2009-07-16
      
+
      View all other issues in [limits].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses FR 32 and DE 16
      
+
+
      
+numeric_limits has functions specifically designed to return NaNs, which
+break the model of Regular (via its axioms.)  While floating point types
+will be acceptible in many algorithms taking Regular values, it is not
+appopriate for this specific API and we need a less refined constraint.
+
      
+
+
      FR 32:
      
+
+
      
+The definition of numeric_limits<> as requiring a regular
+type is both conceptually wrong and operationally illogical. As we
+pointed before, this mistake needs to be corrected. For example, the
+template can be left unconstrained. In fact this reflects a much more
+general problem with concept_maps/axioms and their interpretations. It
+appears that the current text heavily leans toward experimental academic
+type theory.
+
      
+
+
      DE 16:
      
+
+
      
+The class template numeric_limits should not specify the Regular concept
+requirement for its template parameter, because it contains functions
+returning NaN values for floating-point types; these values violate the
+semantics of EqualityComparable.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Move to Open.  Alisdair and Gaby will work on a solution, along with the new
+treatment of axioms in clause 14.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+
      
+
+
+
+
+
+
      
+
      903. back_insert_iterator issue
      
+
      Section: 24.7.1 [back.insert.iterator] Status: NAD
+ Submitter: Dave Abrahams Opened: 2008-09-19  Last modified: 2009-07-16
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+I just noticed this; don't know how far the problem(?) extends or
+whether it's new or existing: back_insert_iterator's operator* is not
+const, so you can't dereference a const one.
+
      
+
+
      [
+Post Summit Daniel adds:
+]
      
+
+
+
      
+
      
+If done, this change should be applied for front_insert_iterator,
+insert_iterator, ostream_iterator, and ostreambuf_iterator as well.
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+Alisdair notes that these all are output iterators.
+Howard points out that ++*i
+would no longer work if we made this change.
+
      
+
      
+Move to NAD.
+
      
+
      
+
+
      [
+2009-05-25 Daniel adds:
+]
      
+
+
+
        
+
      1. 
+If 1009 is accepted, OutputIterator does no longer support post increment.
+
        2. 
+
      2. 
+To support backward compatibility a second overload of operator*
+can be added.
+Note that the HasDereference concept (and the HasDereference part of concept
+Iterator) was specifically refactored to cope with optional const
+qualification and
+to properly reflect the dual nature of built-in operator* as of
+13.5.8 [over.literal]/6.
+
        3. 
+
      
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      905. Mutex specification questions
      
+
      Section: 30.4.1.1 [thread.mutex.class] Status: Dup
+ Submitter: Herb Sutter Opened: 2008-09-18  Last modified: 2009-03-22
      
+
      View other active issues in [thread.mutex.class].
      
+
      View all other issues in [thread.mutex.class].
      
+
      View all issues with Dup status.
      
+
      Duplicate of: 893
      
+
      Discussion:
      
+
      
+A few questions on the current WP,
+N2723:
+
      
+
      
+30.4.1 [thread.mutex.requirements]/24 says an expression
+mut.unlock() "Throws: Nothing." I'm assuming that, per 17.6.3.11 [res.on.required], errors that violate the precondition "The
+calling thread shall own the mutex" opens the door for throwing an
+exception anyway, such as to report unbalanced unlock operations and
+unlocking from a thread that does not have ownership. Right?
+
      
+
      
+30.4.1.1 [thread.mutex.class]/3 (actually numbered paragraph "27"
+in the WP; this is just a typo I think) says
+
      
+
      
+
      
+The behavior of a program is undefined if:
+
      
+
        
+
      • it destroys a mutex object owned by any thread,
        • 
+
      • a thread that owns a mutex object calls lock() or try_lock() on that object, or
        • 
+
      • a thread terminates while owning a mutex object.
        • 
+
      
+
      
+
+
      
+As already discussed, I think the second bullet should be removed, and
+such a lock() or try_lock() should fail with an
+exception or returning false, respectively.
+
      
+
      
+A potential addition to the list would be
+
      
+
        
+
      • a thread unlocks a mutex it does not have ownership of.
        • 
+
      
+
      
+but without that the status quo text endorses the technique of the
+program logically transferring ownership of a mutex to another thread
+with correctness enforced by programming discipline. Was that intended?
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+
      
+Two resolutions: "not a defect" and "duplicate", as follows:
+
      
+
        
+
      • 
+30.4.1 [thread.mutex.requirements]/24: NAD. If the precondition
+fails the program has undefined behaviour and therefore an
+implementation may throw an exception already.
+
        • 
+
      • 
+30.4.1.1 [thread.mutex.class]/3 bullet 2: Already addressed by issue 893.
+
        • 
+
      • 
+30.4.1.1 [thread.mutex.class]/3 proposed addition: NAD. This is
+already covered by the mutex requirements, which have ownership as a
+Precondition.
+
        • 
+
      
+
      
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
+
      
+
      906. ObjectType is the wrong concept to constrain initializer_list
      
+
      Section: 18.9 [support.initlist] Status: NAD Concepts
+ Submitter: Daniel Krügler Opened: 2008-09-26  Last modified: 2009-07-16
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      
+The currently proposed constraint on initializer_list's element type
+E is that is has to meet ObjectType. This is an underspecification,
+because both core language and library part of initializer_list
+make clear, that it references an implicitly allocated array:
+
      
+
      
+8.5.4 [dcl.init.list]/4:
+
      
+
      
+When an initializer list is implicitly converted to a
+std::initializer_list<E>, the object passed is constructed as if the
+implementation allocated an array of N elements of type E, where
+N is the number of elements in the initializer list.[..]
+
      
+
+
      
+18.9 [support.initlist]/2.
+
      
+
+
      
+An object of type initializer_list<E> provides access to an array of
+objects of type const E.[..]
+
      
+
+
      
+Therefore, E needs to fulfill concept ValueType (thus excluding
+abstract class types). This stricter requirement should be added
+to prevent deep instantiation errors known from the bad old times,
+as shown in the following example:
+
      
+
+
      // Header A: (Should concept-check even in stand-alone modus)
+
+template <DefaultConstructible T>
+requires MoveConstructible<T>
+void generate_and_do_3(T a) {
+  std::initializer_list<T> list{T(), std::move(a), T()};
+  ...
+}
+
+void do_more();
+void do_more_or_less();
+
+template <DefaultConstructible T>
+requires MoveConstructible<T>
+void more_generate_3() {
+  do_more();
+  generate_and_do_3(T());
+}
+
+template <DefaultConstructible T>
+requires MoveConstructible<T>
+void something_and_generate_3() {
+  do_more_or_less();
+  more_generate_3();
+}
+
+// Test.cpp
+
+#include "A.h"
+
+class Abstract {
+public:
+  virtual ~Abstract();
+  virtual void foo() = 0; // abstract type
+  Abstract(Abstract&&){} // MoveConstructible
+  Abstract(){} // DefaultConstructible
+};
+
+int main() {
+  // The restricted template *accepts* the argument, but
+  // causes a deep instantiation error in the internal function
+  // generate_and_do_3:
+  something_and_generate_3<Abstract>();
+}
+
      
+
+
      
+The proposed stricter constraint does not minimize the aim to
+support more general containers for which ObjectType would be
+sufficient. If such an extended container (lets assume it's still a
+class template) provides a constructor that accepts an initializer_list
+only this constructor would need to be restricted on ValueType:
+
      
+
+
      template<ObjectType T>
+class ExtContainer {
+public:
+  requires ValueType<T>
+  ExtContainer(std::initializer_list<T>);
+  ...
+};
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+Move to Tentatively Ready.
+
      
+
+
      [
+2009-07 Frankfurt:
+]
      
+
+
+
      
+Need to look at again without concepts.
+
      
+
+
+
+
      Proposed resolution:
      
+
        
+
      1. 
+In 18.9 [support.initlist]/p.1 replace in "header <initializer_list> synopsis"
+the constraint "ObjectType" in the template parameter list by the
+constraint "ValueType".
+
        2. 
+
      
+
+
+
+
+
+
+
      
+
      912. Array swap needs to be conceptualized
      
+
      Section: 25.4.3 [alg.swap] Status: NAD Concepts
+ Submitter: Daniel Krügler Opened: 2008-10-01  Last modified: 2009-07-13
      
+
      View all other issues in [alg.swap].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      
+With the adaption of 809
+we have a new algorithm swap for C-arrays, which needs to be conceptualized.
+
      
+
+
      [
+Post Summit Daniel adds:
+]
      
+
+
+
      
+Recommend as NAD Editorial: The changes have already been applied to the WP
+N2800.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+Move to NAD; the changes have already been made.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Replace in 25.4.3 [alg.swap] before p. 3 until p. 4 by
+
      
+
+
      template <class ValueType T, size_t N>
+requires Swappable<T>
+void swap(T (&a)[N], T (&b)[N]);
+
      
+
      
+
      
+Requires: T shall be Swappable.
+
      
+
      
+Effects: swap_ranges(a, a + N, b);
+
      
+
      
+
      
+
+
+
+
+
+
+
      
+
      913. Superfluous requirements for replace algorithms
      
+
      Section: 25.4.5 [alg.replace] Status: NAD Concepts
+ Submitter: Daniel Krügler Opened: 2008-10-03  Last modified: 2009-07-14
      
+
      View all other issues in [alg.replace].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      
+(A) 25.4.5 [alg.replace]/1:
+
      
+
+
      
+Requires: The expression *first = new_value shall be valid.
+
      
+
+
      
+(B) 25.4.5 [alg.replace]/4:
+
      
+
+
      
+Requires: The results of the expressions *first and new_value shall
+be writable to the result output iterator.[..]
+
      
+
+
      
+Since conceptualization, the quoted content of these clauses is covered
+by the existing requirements
+
      
+
+
      
+(A) OutputIterator<Iter, const T&>
+
      
+
+
      
+and
+
      
+
+
      
+(B) OutputIterator<OutIter, InIter::reference> && OutputIterator<OutIter, const T&>
+
      
+
+
      
+resp, and thus should be removed.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+We agree with the proposed resolution.
+
      
+
      
+Move to Tentatively Ready.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
        
+
      1. 
+
        
+Remove 25.4.5 [alg.replace]/1.
+
        
+
        template<ForwardIterator Iter, class T> 
+  requires OutputIterator<Iter, Iter::reference> 
+        && OutputIterator<Iter, const T&> 
+        && HasEqualTo<Iter::value_type, T> 
+  void replace(Iter first, Iter last, 
+               const T& old_value, const T& new_value); 
+
+template<ForwardIterator Iter, Predicate<auto, Iter::value_type> Pred, class T> 
+  requires OutputIterator<Iter, Iter::reference> 
+        && OutputIterator<Iter, const T&> 
+        && CopyConstructible<Pred> 
+  void replace_if(Iter first, Iter last, 
+                  Pred pred, const T& new_value);
+
        
+
        
+1 Requires: The expression *first = new_value shall be valid.
+
        
+
        
+
        2. 
+
      2. 
+
        
+25.4.5 [alg.replace]/4: Remove the sentence "The results of the
+expressions *first and
+new_value shall be writable to the result output iterator.".
+
        
+
        template<InputIterator InIter, typename OutIter, class T> 
+  requires OutputIterator<OutIter, InIter::reference> 
+        && OutputIterator<OutIter, const T&> 
+        && HasEqualTo<InIter::value_type, T> 
+  OutIter replace_copy(InIter first, InIter last, 
+                       OutIter result, 
+                       const T& old_value, const T& new_value);
+
+template<InputIterator InIter, typename OutIter,
+         Predicate<auto, InIter::value_type> Pred, class T> 
+  requires OutputIterator<OutIter, InIter::reference> 
+        && OutputIterator<OutIter, const T&> 
+        && CopyConstructible<Pred> 
+  OutIter replace_copy_if(InIter first, InIter last, 
+                          OutIter result, 
+                          Pred pred, const T& new_value);
+
        
+
        
+4 Requires: The results of the expressions *first and
+new_value shall be writable to the result output
+iterator. The ranges [first,last) and [result,result +
+(last - first)) shall not overlap.
+
        
+
        
+
        3. 
+
      
+
+
+
+
+
+
      
+
      914. Superfluous requirement for unique
      
+
      Section: 25.4.9 [alg.unique] Status: NAD Concepts
+ Submitter: Daniel Krügler Opened: 2008-10-03  Last modified: 2009-07-14
      
+
      View all other issues in [alg.unique].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      
+25.4.9 [alg.unique]/2: "Requires: The comparison function shall be an
+equivalence relation."
+
      
+
+
      
+The essence of this is already covered by the given requirement
+
      
+
+
      EquivalenceRelation<auto, Iter::value_type> Pred
+
      
+
+
      
+and should thus be removed.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Remove 25.4.9 [alg.unique]/2
+
      
+
+
      template<ForwardIterator Iter>
+  requires OutputIterator<Iter, Iter::reference>
+        && EqualityComparable<Iter::value_type>
+  Iter unique(Iter first, Iter last);
+
+template<ForwardIterator Iter, EquivalenceRelation<auto, Iter::value_type> Pred>
+  requires OutputIterator<Iter, RvalueOf<Iter::reference>::type>
+        && CopyConstructible<Pred>
+  Iter unique(Iter first, Iter last,
+               Pred pred);
+
      
+
      
+
      
+1 Effects: ...
+
      
+
      
+2 Requires: The comparison function shall be an equivalence relation.
+
      
+
      
+
      
+
+
+
+
+
+
      
+
      918. Swap for tuple needs to be conceptualized
      
+
      Section: 20.5.2.6 [tuple.swap] Status: NAD Concepts
+ Submitter: Daniel Krügler Opened: 2008-10-04  Last modified: 2009-07-13
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      
+Issue 522 was accepted after tuple had been conceptualized,
+therefore this step needs to be completed.
+
      
+
+
      [
+Post Summit Daniel adds
+]
      
+
+
+
      
+This is now NAD Editorial (addressed by
+N2844)
+except for item 3 in the proposed wording.
+
      
+
+
      [
+2009-05-01 Daniel adds:
+]
      
+
+
+
      
+As of the recent WP
+(N2857),
+this issue is now completely covered by editorial
+changes (including the third bullet), therefore I unconditionally recommend
+NAD.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+We observed that all the proposed changes have already been applied to the
+Working Draft, rendering this issue moot.
+
      
+
      
+Move to NAD.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
        
+
      1. 
+
        
+In both 20.5.1 [tuple.general]/2 and 20.5.2.7 [tuple.special] change
+
        
+
+
        template <class Swappable... Types>
+void swap(tuple<Types...>& x, tuple<Types...>& y);
+
        
+
+
        2. 
+
+
      2. 
+
        
+In 20.5.2 [tuple.tuple], class tuple definition and in
+20.5.2.6 [tuple.swap], change
+
        
+
+
        requires Swappable<Types>...void swap(tuple&);
+
        
+
+
        3. 
+
+
      3. 
+
        
+In 20.5.2.6 [tuple.swap] remove the current requires-clause, which says:
+
        
+
+
        
+Requires: Each type in Types shall be Swappable
+
        
+
        4. 
+
+
      
+
+
+
+
+
+
+
      
+
      927. Dereferenceable  should be HasDereference
      
+
      Section: 20.8.2.2 [allocator.concepts] Status: NAD Concepts
+ Submitter: Pablo Halpern Opened: 2008-10-23  Last modified: 2009-07-13
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      
+20.8.2.2 [allocator.concepts] contains a reference to a concept named
+Dereferenceable. No such concept exists.
+
      
+
+
      [
+Daniel adds 2009-02-14:
+]
      
+
+
+
      
+The proposal given in the paper
+N2829
+would automatically resolve this issue.
+
      
+
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+This particular set of changes has already been made.
+There are two related changes later on (and possibly also an earlier Example);
+these can be handled editorially.
+
      
+
      
+Move to NAD Editorial.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change all uses of the concept Dereferenceable to
+HasDereference in 20.8.2.2 [allocator.concepts].
+
      
+
+
+
+
+
+
      
+
      928. Wrong concepts used for tuple's comparison operators
      
+
      Section: 20.5.2.5 [tuple.rel] Status: NAD Concepts
+ Submitter: Joe Gottman Opened: 2008-10-28  Last modified: 2009-07-13
      
+
      View all other issues in [tuple.rel].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      
+In the latest working draft for C++0x, tuple's operator== and operator<
+are declared as 
+
      
+
+
      template<class... TTypes, class... UTypes> 
+  requires EqualityComparable<TTypes, UTypes>... 
+  bool operator==(const tuple<TTypes...>& t, const tuple<UTypes...>& u);
+
      
+
+
      
+and
+
      
+
+
      template<class... TTypes, class... UTypes> 
+  requires LessThanComparable<TTypes, UTypes>... 
+  bool operator<(const tuple<TTypes...>& t, const tuple<UTypes...>& u);
+
      
+
+
      
+But the concepts EqualityComparable and LessThanComparable only take one 
+parameter, not two.  Also, even if LessThanComparable could take two 
+parameters, the definition of tuple::operator<() should also require 
+
      
+
+
      LessThanComparable<UTypes, TTypes>... // (note the order) 
+
      
+
+
      
+since the algorithm for tuple::operator< is the following (pseudo-code)
+
      
+
+
      for (size_t N = 0; N < sizeof...(TTypes); ++N) { 
+    if (get<N>(t) < get<N>(u) return true; 
+    else if ((get<N>(u) < get<N>(t)) return false; 
+} 
+
+return false; 
+
      
+
+
      
+Similar problems hold for tuples's other comparison operators.
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+Recommend Tentatively Ready.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+In 20.5.1 [tuple.general] and 20.5.2.5 [tuple.rel] change:
+
      
+
+
      template<class... TTypes, class... UTypes>
+  requires EqualityComparableHasEqualTo<TTypes, UTypes>...
+  bool operator==(const tuple<TTypes...>&, const tuple<UTypes...>&);
+
+template<class... TTypes, class... UTypes>
+  requires LessThanComparableHasLess<TTypes, UTypes>... && HasLess<UTypes, TTypes>...
+  bool operator<(const tuple<TTypes...>&, const tuple<UTypes...>&);
+
+template<class... TTypes, class... UTypes>
+  requires EqualityComparableHasEqualTo<TTypes, UTypes>...
+  bool operator!=(const tuple<TTypes...>&, const tuple<UTypes...>&);
+
+template<class... TTypes, class... UTypes>
+  requires LessThanComparableHasLess<UTTypes, TUTypes>... && HasLess<UTypes, TTypes>...
+  bool operator>(const tuple<TTypes...>&, const tuple<UTypes...>&);
+
+template<class... TTypes, class... UTypes>
+  requires LessThanComparableHasLess<UTTypes, TUTypes>... && HasLess<UTypes, TTypes>...
+  bool operator<=(const tuple<TTypes...>&, const tuple<UTypes...>&);
+
+template<class... TTypes, class... UTypes>
+  requires LessThanComparableHasLess<TTypes, UTypes>... && HasLess<UTypes, TTypes>...
+  bool operator>=(const tuple<TTypes...>&, const tuple<UTypes...>&);
+
      
+
+
+
+
+
+
      
+
      937. Atomics for standard typedef types
      
+
      Section: 29 [atomics] Status: NAD Editorial
+ Submitter: Clark Nelson Opened: 2008-12-05  Last modified: 2009-05-23
      
+
      View other active issues in [atomics].
      
+
      View all other issues in [atomics].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
+
      Addresses US 89
      
+
+
      
+
      
+The types in the table "Atomics for standard typedef types" should be
+typedefs, not classes. These semantics are necessary for compatibility
+with C.
+
      
+
+
      
+Change the classes to typedefs.
+
      
+
      
+
+
      
+N2427
+specified different requirements for atomic analogs of fundamental
+integer types (such as atomic_int) and for atomic analogs of <cstdint>
+typedefs (such as atomic_size_t). Specifically, atomic_int et al. were
+specified to be distinct classes, whereas atomic_size_t et al. were
+specified to be typedefs. Unfortunately, in applying
+N2427
+to the WD, that distinction was erased, and the atomic analog of every <cstdint>
+typedef is required to be a distinct class.
+
      
+
+
      
+It shouldn't be required that the atomic analog of every <cstdint>
+typedef be a typedef for some fundamental integer type. After all,
+<cstdint> is supposed to provide standard names for extended integer
+types. So there was a problem in
+N2427,
+which certainly could have been
+interpreted to require that. But the status quo in the WD is even worse,
+because it's unambiguously wrong.
+
      
+
+
      
+What is needed are words to require the existence of a bunch of type
+names, without specifying whether they are class names or typedef names.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+
      
+Change status to NAD, editorial. See US 89 comment notes above.
+
      
+
      
+Direct the editor to turn the types into typedefs as proposed in the
+comment. Paper approved by committee used typedefs, this appears to have
+been introduced as an editorial change. Rationale: for compatibility
+with C.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+
      
+
+
+
+
+
+
      
+
      941. Ref-qualifiers for assignment operators
      
+
      Section: 17 [library] Status: NAD
+ Submitter: Niels Dekker Opened: 2008-12-18  Last modified: 2009-07-17
      
+
      View other active issues in [library].
      
+
      View all other issues in [library].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+The assignment and equality operators = and == are easily confused, just
+because of their visual similarity, and in this case a simple typo can cause
+a serious bug. When the left side of an operator= is an rvalue, it's
+highly unlikely that the assignment was intended by the programmer:
+
      
+
      if ( func() = value )  // Typical typo: == intended!
+
      
+
      
+Built-in types don't support assignment to an rvalue, but unfortunately,
+a lot of types provided by the Standard Library do.
+
      
+
      
+Fortunately the language now offers a syntax to prevent a certain member
+function from having an rvalue as *this: by adding a ref-qualifier (&)
+to the member function declaration.  Assignment operators are explicitly
+mentioned as a use case of ref-qualifiers, in "Extending Move Semantics
+To *this (Revision 1)",
+N1821 by Daveed
+Vandevoorde and Bronek Kozicki
+
      
+
      
+Hereby I would like to propose adding ref-qualifiers to all appropriate
+assignment operators in the library.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+Move to Open.
+We recommend this be deferred until after the next Committee Draft.
+
      
+
+
      [
+Frankfurt 2009-07:
+]
      
+
+
+
      
+
      
+The LWG declined to move forward with
+N2819.
+
      
+
      
+Moved to NAD.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+A proposed resolution is provided by the paper on this subject,
+N2819,
+Ref-qualifiers for assignment operators of the Standard Library
+
      
+
+
+
+
+
+
      
+
      942. Atomics synopsis typo
      
+
      Section: 29 [atomics] Status: Dup
+ Submitter: Holger Grund Opened: 2008-12-19  Last modified: 2009-03-22
      
+
      View other active issues in [atomics].
      
+
      View all other issues in [atomics].
      
+
      View all issues with Dup status.
      
+
      Duplicate of: 880
      
+
      Discussion:
      
+
+
+
+
      
+I'm looking at 29 [atomics] and can't really make sense of a couple of things.
+
      
+
      
+Firstly, there appears to be a typo in the <cstdatomic> synopsis:
+
      
+
+
      
+
      
+The atomic_exchange overload taking an atomic_address
+is missing the second parameter:
+
      
+
+
      void* atomic_exchange(volatile atomic_address*);
+
      
+
+
      
+should be
+
      
+
+
      void* atomic_exchange(volatile atomic_address*, void*);
+
      
+
+
      
+Note, that this is not covered by 880 "Missing atomic exchange parameter",
+which only talks about the atomic_bool.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change the synopsis in 29 [atomics]/2:
+
      
+
+
      void* atomic_exchange(volatile atomic_address*, void*);
+
      
+
+
+
+
+
+
+
      
+
      945. system_clock::rep not specified
      
+
      Section: 20.9.5.1 [time.clock.system] Status: NAD Editorial
+ Submitter: Pete Becker Opened: 2008-12-19  Last modified: 2009-07-13
      
+
      View all other issues in [time.clock.system].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+In 20.9.5.1 [time.clock.system], the declaration of system_clock::rep says "see
+below", but there is nothing below that describes it.
+
      
+
+
      [
+Howard adds:
+]
      
+
+
+
      
+
      
+This note refers to:
+
      
+
+
      
+-2- system_clock::duration::min() < system_clock::duration::zero() shall be true.
+
      
+
+
      
+I.e. this is standardeze for "system_clock::rep is signed".
+Perhaps an editorial note along the lines of:
+
      
+
+
      
+-2- system_clock::duration::min() < system_clock::duration::zero()
+shall be true. [Note: system_clock::rep shall be signed. -- end note].
+
      
+
+
      
+?
+
      
+
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the direction of the proposed resolution.
+Move to NAD Editorial.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Add a note to 20.9.5.1 [time.clock.system], p2:
+
      
+
      
+-2- system_clock::duration::min() < system_clock::duration::zero()
+shall be true. [Note: system_clock::rep shall be signed. -- end note].
+
      
+
+
+
+
+
+
      
+
      946. duration_cast improperly specified
      
+
      Section: 20.9.3.7 [time.duration.cast] Status: NAD
+ Submitter: Pete Becker Opened: 2008-12-20  Last modified: 2009-07-13
      
+
      View all other issues in [time.duration.cast].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+20.9.3.7 [time.duration.cast]/3:
+
+
      
+.... All intermediate computations shall be
+carried out in the widest possible representation... .
+
      
+
+
      
+So ignoring
+floating-point types for the moment, all this arithmetic has to be done
+using the implementation's largest integral type, even if both arguments
+use int for their representation. This seems excessive. And it's not at
+all clear what this means if we don't ignore floating-point types.
+
      
+
+
      
+This issue is related to 952.
+
      
+
+
      [
+Howard adds:
+]
      
+
+
+
      
+
      
+The intent of this remark is that intermediate computations are carried out
+using:
+
      
+
+
      common_type<typename ToDuration::rep, Rep, intmax_t>::type
+
      
+
+
      
+The Remark was intended to be clarifying prose supporting the rather algorithmic description
+of the previous paragraph.  I'm open to suggestions.  Perhaps the entire paragraph
+3 (Remarks) would be better dropped?
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+We view this as a specific case of issue 952,
+and should be resolved when that issue is resolved.
+
      
+
      
+Move to NAD.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+
      
+
+
+
+
+
+
      
+
      952. Various threading bugs #2
      
+
      Section: 20.9.3.7 [time.duration.cast] Status: NAD Editorial
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-07-13
      
+
      View all other issues in [time.duration.cast].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+20.9.3.7 [time.duration.cast] specifies an implementation and imposes
+requirements in text (and the implementation doesn't satisfy all of the
+text requirements). Pick one.
+
      
+
+
      
+This issue is related to 946.
+
      
+
+
      [
+2009-05-10 Howard adds:
+]
      
+
+
+
      
+
      
+The Remarks paragraph is an English re-statement of the preceeding
+Returns clause.  It was meant to be clarifying and motivating, not
+confusing.  I'm not aware with how the Remarks contradicts the Returns clause
+but I'm ok with simply removing the Remarks.
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+Pete suggests that this could be resolved
+by rephrasing the Remarks to Notes.
+
      
+
      
+Move to NAD Editorial.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+
      
+
+
+
+
+
+
      
+
      969. What happened to Library Issue 475?
      
+
      Section: 25.3.4 [alg.foreach] Status: NAD Editorial
+ Submitter: Stephan T. Lavavej Opened: 2009-01-12  Last modified: 2009-07-13
      
+
      View all other issues in [alg.foreach].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+Library Issue 475 has CD1 status, but the non-normative note in
+N2723
+was removed in
+N2798
+(25.3.4 [alg.foreach] in both drafts).
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+Move to NAD Editorial.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Restore the non-normative note. It might need to be expressed in terms of concepts.
+
      
+
+
+
+
+
+
      
+
      972. The term "Assignable" undefined but still in use
      
+
      Section: 17 [library] Status: NAD Editorial
+ Submitter: Niels Dekker Opened: 2009-01-07  Last modified: 2009-07-13
      
+
      View other active issues in [library].
      
+
      View all other issues in [library].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+Previous versions of the Draft had a table, defining the Assignable 
+requirement.  For example 
+N2134
+Table 79, "Assignable requirements". But I guess the term "Assignable" 
+is outdated by now, because the current Committee Draft provides 
+MoveAssignable, CopyAssignable, and TriviallyCopyAssignable concepts 
+instead. And as far as I can see, it no longer has a definition of 
+Assignable. (Please correct me if I'm wrong.) Still the word 
+"Assignable" is used in eight places in the Draft, 
+N2800.
+
      
+
+
      
+Are all of those instances of "Assignable" to be replaced by "CopyAssignable"? 
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+Move to NAD Editorial.
+
      
+
+
+
      Proposed resolution:
      
+
+
      
+Change Exception Propagation 18.8.5 [propagation]:
+
      
+
      
+exception_ptr shall be DefaultConstructible, CopyConstructible,
+CopyAssignable and EqualityComparable.
+
      
+
+
      
+Change Class template reference_wrapper 20.7.5 [refwrap]:
+
      
+
      
+reference_wrapper<T> is a CopyConstructible and CopyAssignable wrapper around a reference to an object of type T.
+
      
+
      
+Change Placeholders 20.7.12.1.4 [func.bind.place]:
+
      
+
      
+It is implementation defined whether placeholder types are CopyAssignable. CopyAssignable placeholders' copy assignment operators shall not throw exceptions.
+
      
+
      
+Change Class template shared_ptr 20.8.10.2 [util.smartptr.shared]:
+
      
+
      
+Specializations of shared_ptr shall be CopyConstructible, CopyAssignable, and LessThanComparable...
+
      
+
      
+Change Class template weak_ptr 20.8.10.3 [util.smartptr.weak]:
+
      
+
      
+Specializations of weak_ptr shall be CopyConstructible, CopyAssignable, and LessThanComparable...
+
      
+
      
+Change traits typedefs 21.2.2 [char.traits.typedefs] (note: including deletion of reference to 23.1!):
+
      
+
      
+Requires: state_type shall meet the requirements of CopyAssignable (23.1), CopyConstructible (20.1.8), and DefaultConstructible types.
+
      
+
      
+Change Class seed_seq 26.5.7.1 [rand.util.seedseq] (note again: including deletion of reference to 23.1!):
+
      
+
      
+In addition to the requirements set forth below, instances of
+seed_seq shall meet the requirements of CopyConstructible (20.1.8) and of CopyAssignable (23.1).
+
      
+
+
      
+Note: The proposed resolution of this issue does not deal with the
+instance of the term "Assignable" in D.9.1 [auto.ptr], as this is dealt
+with more specifically by LWG 973, "auto_ptr characteristics", submitted
+by Maarten Hilferink.
+
      
+
+
+
+
+
+
+
      
+
      973. auto_ptr characteristics
      
+
      Section: D.9.1 [auto.ptr] Status: NAD Editorial
+ Submitter: Maarten Hilferink Opened: 2009-01-21  Last modified: 2009-07-13
      
+
      View all other issues in [auto.ptr].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+I think that the Note of D.9.1 [auto.ptr], paragraph 3 needs a rewrite 
+since "Assignable" is no longer defined as a concept. 
+The relationship of auto_ptr with the new CopyAssignable, MoveAssignable,
+ and MoveConstructible concepts should be clarified.
+Furthermore, since the use of auto_ptr is depreciated anyway,
+ we can also omit a description of its intended use.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the intent of the proposed resolution.
+Move to NAD Editorial.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change D.9.1 [auto.ptr], paragraph 3:
+
      
+
+
      
+The auto_ptr provides a semantics of strict ownership. An
+auto_ptr owns the ob ject it holds a pointer to. Copying an
+auto_ptr copies the pointer and transfers ownership to the
+destination. If more than one auto_ptr owns the same ob ject at
+the same time the behavior of the program is undefined. [Note:
+The uses of auto_ptr include providing temporary
+exception-safety for dynamically allocated memory, passing ownership of
+dynamically allocated memory to a function, and returning dynamically
+allocated memory from a function.
+auto_ptr does not meet the
+CopyConstructible and Assignable requirements for
+standard library container elements and thus instantiating a standard
+library container with an auto_ptr results in undefined
+behavior.
+
+Instances of auto_ptr shall
+meet the MoveConstructible and MoveAssignable
+requirements, but do not meet the CopyConstructible and
+CopyAssignable requirements.
+-- end note]
+
      
+
+
+
+
+
+
      
+
      979. Bad example
      
+
      Section: 24.5.2 [move.iterators] Status: NAD Editorial
+ Submitter: Howard Hinnant Opened: 2009-02-03  Last modified: 2009-07-13
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
      
+24.5.2 [move.iterators] has an incorrect example:
+
      
+
+
      
+
      
+-2- [Example:
+
      
+
+
      set<string> s; 
+// populate the set s 
+vector<string> v1(s.begin(), s.end());          // copies strings into v1 
+vector<string> v2(make_move_iterator(s.begin()), 
+                  make_move_iterator(s.end())); // moves strings into v2
+
      
+
+
      
+-- end example]
+
      
+
      
+
+
      
+One can not move from a set because the iterators return const
+references.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution. Move to NAD Editorial.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change 24.5.2 [move.iterators]/2:
+
      
+
+
      
+
      
+-2- [Example:
+
      
+
+
      setlist<string> s; 
+// populate the setlist s 
+vector<string> v1(s.begin(), s.end());          // copies strings into v1 
+vector<string> v2(make_move_iterator(s.begin()), 
+                  make_move_iterator(s.end())); // moves strings into v2
+
      
+
+
      
+-- end example]
+
      
+
      
+
+
+
+
+
+
      
+
      980. mutex lock() missing error conditions
      
+
      Section: 30.4.1 [thread.mutex.requirements] Status: NAD
+ Submitter: Ion Gaztañaga Opened: 2009-02-07  Last modified: 2009-03-22
      
+
      View other active issues in [thread.mutex.requirements].
      
+
      View all other issues in [thread.mutex.requirements].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+POSIX 2008 adds two return values for pthread_mutex_xxxlock():
+EOWNERDEAD (owner_dead) and ENOTRECOVERABLE
+(state_not_recoverable). In the first case the mutex is locked,
+in the second case the mutex is not locked.
+
      
+
+
      
+Throwing an exception in the first case can be incompatible with the use
+of Locks, since the Lock::owns_lock() will be false when the lock is
+being destroyed.
+
      
+
+
      
+Consider:
+
      
+
+
      //Suppose mutex.lock() throws "owner_dead"
+unique_lock ul(&mutex);
+//mutex left locked if "owner_dead" is thrown
+
      
+
+
      
+Throwing an exception with owner_dead might be also undesirable if
+robust-mutex support is added to C++ and the user has the equivalent of
+pthread_mutex_consistent() to notify the user has fixed the corrupted
+data and the mutex state should be marked consistent.
+
      
+
+
        
+
      1. 
+For state_not_recoverable add it to the list of Error conditions:
+
        2. 
+
      2. 
+For owner_dead, no proposed resolution.
+
        3. 
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Not a defect. Handling these error conditions is an implementation
+detail and must be handled below the C++ interface.
+
      
+
+
+
+
      Proposed resolution:
      
+
+
      
+Add to 30.4.1 [thread.mutex.requirements], p12:
+
      
+
+
      
+
      
+-12- Error conditions:
+
      
+
+
        
+
      • 
+operation_not_permitted -- if the thread does not have the necessary permission to change 
+the state of the mutex.
+
        • 
+
      • 
+resource_deadlock_would_occur -- if the current thread already owns the mutex and is able 
+to detect it.
+
        • 
+
      • 
+device_or_resource_busy --  if the mutex is already locked and blocking is not possible.
+
        • 
+
      • 
+state_not_recoverable -- if the state protected by the mutex is not recoverable.
+
        • 
+
      
+
      
+
+
+
+
+
+
      
+
      988. Reflexivity meaningless?
      
+
      Section: 20.2.6 [concept.comparison] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2009-02-24  Last modified: 2009-07-16
      
+
      View all other issues in [concept.comparison].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+20.2.6 [concept.comparison] p2:
+
      
+
      
+Due to the subtle meaning of == inside axioms, the Reflexivity axiom does
+not do anything as written. It merely states that a value is substitutable
+with itself, rather than asserting a property of the == operator.
+
      
+
+
+Original proposed resolution:
+
+
+
      
+Change the definition of Reflexivity in 20.2.6 [concept.comparison]:
+
      
+
+
      axiom Reflexivity(T a) { (a == a) == true; }
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+
      
+Alisdair: I was wrong.
+
      
+
      
+Recommend NAD.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+NAD.
+
      
+
+
+
+
+
+
      
+
      989. late_check and library
      
+
      Section: 17 [library] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-02-24  Last modified: 2009-07-16
      
+
      View other active issues in [library].
      
+
      View all other issues in [library].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      
+The example in 6.9p2 shows how late_check blocks inhibit concept_map lookup
+inside a constrained context, and so inhibit concept map adaption by users
+to meet template requirements.
+
      
+
      
+Do we need some text in clause 17 prohibitting use of late_check in library
+template definitions unless otherwise documented?
+
      
+
+
      [
+Doug adds:
+]
      
+
+
+
      
+We need something like this, but it should be a more general statement
+about implementations respecting the concept maps provided by the
+user. Use of late_check is one way in which implementations can
+subvert the concept maps provided by the user, but there are other
+ways as well ("pattern-based" overloading, tricks with "auto" concept
+maps and defaulted associated type arguments).
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+Move to Open, pending proposed wording from Alisdair and/or Doug for further review.
+
      
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      992. Response to UK 169
      
+
      Section: 17.6.1.1 [contents] Status: NAD
+ Submitter: P.J. Plauger Opened: 2009-03-03  Last modified: 2009-07-22
      
+
      View all other issues in [contents].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      Addresses UK 169
      
+
      
+This phrasing contradicts later freedom to implement the C standard
+library portions in the global namespace as well as std. (17.6.2.3p4)
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+The proposed wording seems to go too far.
+Move back to Open.
+
      
+
+
      [
+2009-07 Frankfurt:
+]
      
+
+
+
      
+
      
+Howard to add NB reference to the description of this issue.
+
      
+
      
+Move to NAD. This comment is informative and not normative by the use of
+the word "are" instead of the word "shall."
+
      
+
      
+A note linking to Annex D would help clarify the intention, here.
+
      
+
      
+Robert to Open a separate issue proposing that the standard C headers be
+undeprecated, for the purpose of clarifying the standard.
+
      
+
      
+
+
      [
+2009-07-22 Bill modified the proposed wording with a clarifying footnote.
+]
      
+
+
+
+
+
      Proposed resolution:
      
+
      
+Add a footnote to 17.6.1.1 [contents], p2:
+
      
+
+
      
+
      
+-2- All library entities except macros, operator new and operator
+delete are defined within the namespace std or namespaces
+nested within namespace std*.
+
      
+
+
      
+*The C standard library headers D.5 [depr.c.headers] also define
+names within the global namespace, while the C++ headers for
+C library facilities 17.6.1.2 [headers] may also define names within
+the global namespace.
+
      
+
      
+
+
+
+
+
+
+
      
+
      995. Operational Semantics Unclear
      
+
      Section: 17.5.1.3 [structure.requirements] Status: NAD
+ Submitter: David Abrahams Opened: 2009-03-06  Last modified: 2009-07-13
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
      
+As a practical matter there's disagreement on the meaning of operational
+semantics.  If the text in 17.5.1.3 [structure.requirements]p4 isn't
+clear, it should be clarified.  However, it's not clear whether the
+disagreement is merely due to people not being aware of the text.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+Agree with the recommended NAD resolution.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Recommend NAD.  The text in 17.5.1.3 [structure.requirements] is
+perfectly clear.
+
      
+
+
+
+
+
+
      
+
      1000. adjacent_find is over-constrained
      
+
      Section: 25.3.8 [alg.adjacent.find] Status: NAD Concepts
+ Submitter: Chris Jefferson Opened: 2009-03-09  Last modified: 2009-07-15
      
+
      View all other issues in [alg.adjacent.find].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      
+Addresses UK 296
+
      
+
+
      
+adjacent_find in C++03 allows an arbitrary predicate, but in C++0x
+EqualityComparable/EquivalenceRelation is required. This forbids a
+number of use cases, including:
+
      
+
      
+
+
+
+
+
+
+
+
+
+
      
+adjacent_find(begin, end, less<double>)
+
+Find the first
+place where a range is not ordered in decreasing order - in use to check
+for sorted ranges.
+
      
+adjacent_find(begin, end, DistanceBiggerThan(6) ) )
+
+Find the first
+place in a range where values differ by more than a given value - in use
+to check an algorithm which produces points in space does not generate
+points too far apart.
+
      
+
      
+
+
      
+A number of books use predicate which are not equivalence relations in
+examples, including "Thinking in C++" and "C++ Primer".
+
      
+
+
      
+Adding the requirement that the predicate is an EquivalenceRelation
+does not appear to open up any possibility for a more optimised algorithm.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change the definition of adjacent_find in the synopsis of 25 [algorithms]
+and 25.3.8 [alg.adjacent.find] to:
+
      
+
+
      template<ForwardIterator Iter> 
+  requires EqualityComparableHasEqualTo<Iter::value_type, Iter::value_type>
+  Iter adjacent_find(Iter first, Iter last);
+
+template<ForwardIterator Iter, EquivalenceRelationPredicate<auto, Iter::value_type, Iter::value_type> Pred> 
+  requires CopyConstructible<Pred> 
+  Iter adjacent_find(Iter first, Iter last, Pred pred);
+
      
+
+
+
+
+
+
      
+
      1001. Pointers, concepts and headers
      
+
      Section: 17 [library] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-10  Last modified: 2009-07-18
      
+
      View other active issues in [library].
      
+
      View all other issues in [library].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses UK 78
      
+
+
      
+Related to 1063.
+
      
+
+
      
+This is effectively an extension of LWG issue 343.
+
      
+
      
+We know there is an increasing trend (encouraged by conformance testers and
+some users) that each library header should supply no more than required to
+satisfy the synopsis in the standard.  This is typically achieved by
+breaking larger headers into smaller subsets, and judicious use of forward
+declarations.
+
      
+
      
+If we apply this policy to C++0x (per
+N2800)
+it will be very surprising for
+people using library algorithms over ranges defined by pointers that they
+must #include <iterator_concepts> for their code to compile again.  That is
+because pointers do not satisfy any of the iterator concepts without the
+concept_map supplied in this header.
+
      
+
      
+Therefore, I suggest we should require all library headers that make use of
+iterator concepts are specifically required to #include <iterator_concepts>.
+
      
+
      
+At a minimum, the list of headers would be: (assuming all are constrained by
+concepts)
+
      
+
      algorithm
+array
+deque
+forward_list
+initializer_list
+iterator
+locale
+list
+map
+memory          // if 1029 is adopted
+memory_concepts
+numeric
+random
+regex
+set
+string
+tuple
+unordered_map
+unordered_set
+utility
+vector
+
      
+
+
      [
+Ganesh adds:
+]
      
+
+
+
      
+
      
+The same problems exists for <memory_concepts> and
+<container_concepts>.
+
      
+
      
+In order to compile <vector> you just need the
+definitions of the concepts in <memory_concepts>, the
+concept maps defined there are not necessary. Yet, from the user point
+of view, if the concept map template for AllocatableElement are
+not in scope, <vector> is pretty useless. Same for
+<tuple> and ConstructibleWithAllocator.
+
      
+
      
+Similarly, <queue> is not very useful if the concept map
+template for QueueLikeContainer is not in scope, although the
+definition of concept alone is theoretically sufficient.
+
      
+
      
+There's a pattern here: if a concept has concept maps "attached", they
+should never be separated.
+
      
+
      
+
+
      [
+Beman provided the proposed resolution for the May 2009 mailing. He 
+comments:
+]
      
+
+
+
      
+
+
      Initially I tried to specify exactly what header should include what other 
+headers. This was verbose, error prone, hard to maintain, and appeared to add 
+little value compared to just stating the general rule.
      
+
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+Pete believes the proposed wording overconstrains implementers.
+Instead of specifying the mechanism,
+he prefers a solution that spells out what needs to be declared,
+rather than how those declarations are to be provided,
+e.g.,
+
      
+
      
+A C++ header shall provide the names
+that are required to be defined in that header.
+
      
+
      
+Bill suggests approaching the wording from a programmer's perspective.
+We may want to consider promising that certain widely-used headers
+(e.g., the concept headers) are included when needed by other headers.
+He feels, however, there is nothing broken now,
+although we may want to consider "something nicer."
+
      
+
      
+Move to Open status.
+
      
+
+
      
+
+
      [
+2009-06-16 Beman updated the proposed resolution:
+]
      
+
+
+
      
+  
        
+    
      • The mechanism is no longer specified, as requested in Batavia.
        • 
+    
      • The footnote has been removed since it specified mechanism and also did 
+    not reflect existing practice.
        • 
+    
      • A sentence was added that makes it clear that the existing practice is 
+    permitted.
        • 
+  
      
+
      
+
+
      [
+2009-07-15 Beman updated the proposed resolution:
+]
      
+
+
+
      [
+2009-07-17 Beman updated the proposed resolution based on feedback from the LWG in Frankfurt:
+]
      
+
+
+
      
+
        
+
      • Strike two pieces of text considered unnecessary.
        • 
+
      • Change "definitions" to "declarations and definitions" in two places.
        • 
+
      • Wording tightened slightly.
        • 
+
      
+
      
+
+
      [
+2009-07 Frankfurt:
+]
      
+
+
+
      
+
      
+Revised Proposed Resolution:
+
      
+
      
+A C++ header may include other C++ headers. A C++ header shall provide
+the declarations and definitions that appear in its synopsis (3.2
+[basic.def.odr]). A C++ header shown in its synopsis as including other
+C++ headers shall provide the declarations and definitions that appear
+in the synopses of those other headers.
+
      
+
      
+Alisdair: Does this address the BSI comment?
+
      
+
      
+Beman: There were several overlapping comments. I tried to handle them
+all with one resolution.
+
      
+
      
+Alisdair: I'd prefer to see this closed as NAD and have this resolution
+be the subject of some other, new issue.
+
      
+
      
+Move to NAD Concepts. Howard to open a new issue (1178) in Ready state with the
+Proposed Resolution above. Beman will write up a discussion for the new
+issue.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
      Change 17.6.4.2 [res.on.headers], Headers, paragraph 1, as indicated:
      
+
+
      
+
+
      
+A C++ header may include other C++
+headers.[footnote] A C++ header shall provide
+the declarations and definitions that appear in its synopsis
+(3.2 [basic.def.odr]). A C++ header shown in its synopsis as including 
+other C++ headers shall provide the same declarations and definitions as
+if those other headers were included.
+
      
+
+  
      [footnote] C++ headers must include a C++ header that contains 
+  any needed definition (3.2).
      
+
      
+
+
+
+
+
+
+
      
+
      1002. Response to UK 170
      
+
      Section: 17.6.1.2 [headers] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
      
+
      View all other issues in [headers].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
+
      Addresses UK 170
      
+
+
      
+One of goals of C++0x is to make language easier to teach and for
+'incidental' programmers. The fine-grained headers of the C++ library
+are valuable in large scale systems for managing dependencies and
+optimising build times, but overcomplicated for simple development and
+tutorials. Add additional headers to support the whole library through a
+single include statement.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We do not all agree that this is an issue,
+but we agree that if it needs solving this is the right way to do it.
+Move to Tentatively Ready.
+
      
+
+
      [
+2009-07-06 Beman notes:
+]
      
+
+
+
      
+
      
+This issue
+adds a header <std>.
+
      
+
      
+There is a paper to be looked at,
+N2905
+Aggregation headers, that adds
+a header <std-all> that is the same thing except it excludes
+deprecated headers.
+N2905
+also proposes a second aggregation header.
+
      
+
      
+Seems like this issue should be held in abeyance until the LWG has had
+a chance to look at N2905.
+
      
+
      
+
+
      [
+2009-07-06 Howard:  I've pulled this issue back to Review.
+]
      
+
+
+
      [
+2009-07 Frankfurt
+]
      
+
+
+
      
+No consensus for change.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Insert a new paragraph in 17.6.1.2 [headers] between p4 and p5
+
      
+
      
+An additional header <std> shall have the effect of
+supplying the entire standard library.  [Note: for example, it
+might be implemented as a file with an #include statement for each of the
+headers listed in tables 13 and 14. -- end note]
+
      
+
+
+
+
+
+
      
+
      1003. Response to JP 23
      
+
      Section: 17.6.1.3 [compliance] Status: NAD
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-18
      
+
      View all other issues in [compliance].
      
+
      View all issues with NAD status.
      
+
      Discussion:
      
+
+
      Addresses JP 23
      
+
+
      
+There is a freestanding implementation including
+<type_traits>, <array>,
+<ratio>, lately added to Table 13, C++ library headers.
+Programmers think them useful and hope that these headers are also added
+to Table 15, C++ headers for freestanding implementations, that shows
+the set of headers which a freestanding implementation shall include at
+least.
+
      
+
+
      Original proposed resolution
      
+
+
      
+Add <type_traits>, <array>,
+<ratio> to Table 15.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+
      
+ The <array> header has far too many dependencies to require for a
+free-standing implementation.
+
      
+
      
+The <ratio> header would be useful, has no dependencies, but is not
+strictly necessary.
+
      
+
      
+The <type_traits> header is fundamentally a core language facility with a
+library interface, so should be supported.
+
      
+
+
      
+(it is anticipated the resolution will come via an update to paper
+N2814)
+(see also LWG 833)
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+Leave in Review status pending a paper on freestanding implementations
+by Martin Tasker.
+
      
+
+
      [
+2009-07 Frankfurt:
+]
      
+
+
+
      
+
      
+Move this to NAD.
+
      
+
      
+We considered all of the listed headers, and found a compelling case
+only for the inclusion of <type_traits> in the list of headers required
+of a freestanding implementation.
+
      
+
      
+See Martin Tasker's paper 
+Fixing Freestanding
+which provides the wording to include <type_traits> into freestanding
+implementations.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Add <type_traits> to Table 15.
+
      
+
+
+
+
+
+
+
      
+
      1005. numeric_limits partial specializations not concept enabled
      
+
      Section: 18.3.1.1 [numeric.limits] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses JP 26
      
+
+
      
+numeric_limits [partial specializations] does not use concept.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Alisdair will provide a soltion as part of treatment of axioms and LWG 902.
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+Alisdair recommends NAD as the partial specializations are already
+constrained by requirements on the primary template.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+The Working Draft does not in general repeat a primary template's constraints
+in any specializations.
+Move to NAD.
+
      
+
+
      [
+2009-05-25 Howard adds:
+]
      
+
+
+
      
+A c++std-lib thread starting at c++std-lib-23880 has cast doubt that NAD is the
+correct resolution of this issue.  Indeed the discussion also casts doubt that
+the current proposed wording is the correct resolution as well.  Personally I'm
+inclined to reset the status to Open.  However I'm reverting the status to 
+that which it had prior to the Batavia recommendation.  I'm setting back to Review.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 18.3.1.1 [numeric.limits]:
+
      
+
+
      template<class Regular T> class numeric_limits<const T>;
+template<class Regular T> class numeric_limits<volatile T>;
+template<class Regular T> class numeric_limits<const volatile T>;
+
      
+
+
+
+
+
+
+
      
+
      1007. throw_with_nested not concept enabled
      
+
      Section: 18.8.6 [except.nested] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
      
+
      View other active issues in [except.nested].
      
+
      View all other issues in [except.nested].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses JP 29
      
+
+
      
+throw_with_nested does not use concept.
+
      
+
+
      [
+Summit:
+]
      
+
+ 
+
      
+Agreed.
+
      
+
+
+
+
      Proposed resolution:
      
+
+
      
+Alisdair initially proposed wording in
+N2619.
+
      
+
      
+We are awaiting an updated paper based on feedback from the San Francisco
+review.
+
      
+
+
+
+
+
+
      
+
      1010. operator-= should use default in concept
      
+
      Section: 24.2.6 [random.access.iterators] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-16
      
+
      View other active issues in [random.access.iterators].
      
+
      View all other issues in [random.access.iterators].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses UK 263
      
+
+
      
+This requirement on operator-= would be better expressed as a default
+implementation in the concept, with a matching axiom.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+The proposed resolution should also remove
+paragraph 5 and the declaration that precedes it.
+Further, we should provide an axiom
+that captures the desired semantics.
+This may be a broader policy to be applied.
+Move to Open.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 24.2.6 [random.access.iterators]:
+
      
+
+
      concept RandomAccessIterator<typename X> : BidirectionalIterator<X>, LessThanComparable<X> {
+  ...
+  X& operator-=(X& x, difference_type n) { return x += -n; }
+  ...
+}
+
      
+
+
+
+
+
+
+
      
+
      1013. Response to UK 305
      
+
      Section: 25.5.7 [alg.min.max] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-16
      
+
      View all other issues in [alg.min.max].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
+
      Addresses UK 305
      
+
+
      
+The negative requirement on IsSameType is a hold-over from an earlier
+draught with a variadic template form of min/max algorith. It is no
+longer necessary.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
      [
+2009-07 Frankfurt
+]
      
+
+
+
      
+We believe this is NAD, but this needs to be reviewed against the
+post-remove-concepts draft.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change 25 [algorithms]:
+
      
+
+
      template<class T, StrictWeakOrder<auto, T> Compare>
+  requires !SameType<T, Compare> && CopyConstructible<Compare>
+  const T& min(const T& a, const T& b, Compare comp);
+...
+template<class T, StrictWeakOrder<auto, T> Compare>
+  requires !SameType<T, Compare> && CopyConstructible<Compare>
+  const T& max(const T& a, const T& b, Compare comp);
+...
+template<class T, StrictWeakOrder<auto, T> Compare>
+  requires !SameType<T, Compare> && CopyConstructible<Compare>
+  pair<const T&, const T&> minmax(const T& a, const T& b, Compare comp);
+
      
+
+
      
+Change 25.5.7 [alg.min.max], p1, p9 and p17:
+
      
+
+
      template<class T, StrictWeakOrder<auto, T> Compare>
+  requires !SameType<T, Compare> && CopyConstructible<Compare>
+  const T& min(const T& a, const T& b, Compare comp);
+...
+template<class T, StrictWeakOrder<auto, T> Compare>
+  requires !SameType<T, Compare> && CopyConstructible<Compare>
+  const T& max(const T& a, const T& b, Compare comp);
+...
+template<class T, StrictWeakOrder<auto, T> Compare>
+  requires !SameType<T, Compare> && CopyConstructible<Compare>
+  pair<const T&, const T&> minmax(const T& a, const T& b, Compare comp);
+
      
+
+
+
+
+
+
+
      
+
      1015. Response to UK 199
      
+
      Section: 20.2.1 [concept.transform] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
      
+
      View all other issues in [concept.transform].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses UK 199
      
+
+
      
+The requirement that programs do not supply concept_maps should
+probably be users do not supply their own concept_map
+specializations. The program will almost certainly supply
+concept_maps - the standard itself supplies a specialization
+for RvalueOf references. Note that the term program is
+defined in 3.5 [basic.link]p1 and makes no account of the
+standard library being treated differently to user written code.
+
      
+
+
      [
+2009-05-09 Alisdair adds:
+]
      
+
+
+
      
+
      
+The same problem is present in the words added for the
+LvalueReference/RvalueReference concepts last meeting.
+
      
+
      
+With three subsections requiring the same constraint, I'm wondering if there
+is a better way to organise this section.
+Possible 20.2.1 -> 20.2.3 belong in the fundamental concepts clause in
+14.10.4 [concept.support]?  While they can be implemented purely as a
+library feature without additional compiler support, they are pretty
+fundamental and we want the same restriction on user-concept maps as is
+mandated there.
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the issue,
+but believe the wording needs further improvement.
+We want to investigate current definitions for nomenclature such as
+"user" and "program."
+Move to Open pending the recommended investigation.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 20.2.1 [concept.transform] p2:
+
      
+
+
      
+-2- A program user shall not provide concept maps for
+any concept in 20.1.1.
+
      
+
+
      
+Change 20.2.2 [concept.true] p2:
+
      
+
+
      
+-2- Requires: a program user shall not
+provide a concept map for the True concept.
+
      
+
+
      
+Change 20.2.3 [concept.classify] p2:
+
      
+
+
      
+-2- Requires: a programuser shall not provide concept
+maps for any concept in this section.
+
      
+
+
+
+
+
+
+
      
+
      1016. Response to JP 33
      
+
      Section: 20.2.6 [concept.comparison] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
      
+
      View all other issues in [concept.comparison].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses JP 33
      
+
+
      
+LessThanComparable and EqualityComparable don't correspond to NaN. 
+
      
+
+
      Original proposed resolution:
      
+
+
      
+Apply concept_map to these concepts at FloatingPointType.
+
      
+
+
      [
+Post Summit, Alisdair adds:
+]
      
+
+
+
      
+
      
+I don't understand the proposed resolution - there is no such thing as a
+'negative' concept_map, and these concepts are auto concepts that match
+float/double etc. Also not clear how we are supposed to match values to
+concepts.
+
      
+
      
+Recommend NAD and treat as a subset of issue 902.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Recommend NAD.
+
      
+
+
+
+
+
+
      
+
      1017. Response to US 66
      
+
      Section: 20.2.11 [concept.regular] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses US 66
      
+
+
      
+Application of the Regular concept to floating-point types appears to be
+controversial (see long discussion on std-lib reflector). 
+
      
+
+
      Original proposed resolution:
      
+
+
      
+State that the Regular concept does not apply to floating-point types. 
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+
      
+Recommend that we handle the same as JP 33 / 1016.
+
      
+
      
+
+
      [
+Post Summit, Alisdair adds:
+]
      
+
+
+
      
+
      
+Recommend Open, and review after resolution of 902 and revised axiom
+feature.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      1018. Response to US 70
      
+
      Section: 20.6 [meta] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
      
+
      View other active issues in [meta].
      
+
      View all other issues in [meta].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses US 70
      
+
+
      
+Specifications now expressed via narrative text are more accurately and
+clearly expressed via executable code.
+
      
+
      
+Wherever concepts are available that directly match this section's type
+traits, express the traits in terms of the concepts instead of via
+narrative text. Where the type traits do not quite match the
+corresponding concepts, bring the two into alignment so as to avoid two
+nearly-identical notions.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+
      
+We think that this is a good idea, but it requires a lot of work. If someone
+submits a paper proposing specific changes, we would be happy to review it
+at the next meeting.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      1022. Response to UK 212
      
+
      Section: 20.8.10.7 [util.dynamic.safety] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
      
+
      View all other issues in [util.dynamic.safety].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
+
      Addresses UK 212
      
+
+
      
+The pointer-safety API is nothing to do with smart pointers, so does not
+belong in 20.8.10 [util.smartptr]. In fact it is a set of language
+support features are really belongs in clause 18 [language.support], with the contents declared in a header that
+deals with language-support of memory management.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Agree in principle, but not with the proposed resolution. We believe it
+belongs either a subsection of either 20 [utilities] or 20.8 [memory]
+as part of the general reorganization of 20 [utilities]. The
+declaration should stay in
+<memory>.
+
      
+
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      1023. Response to DE 22
      
+
      Section: 20.7.16.2 [func.wrap.func] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-13
      
+
      View all other issues in [func.wrap.func].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
+
      Addresses DE 22
      
+
+
      Related to issue 1114.
      
+
+
      
+The conditions for deriving from std::unary_function and
+std::binary_function are unclear: The condition would also be satisfied if
+ArgTypes were std::vector<T1>, because it (arguably)
+"contains" T1.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Agree. std::reference_wrapper has the same structure, and we
+suggest that std::function be presented in the same way as
+std::reference_wrapper.
+
      
+
+
      [
+2009-05-09 Alisdair adds:
+]
      
+
+
+
      
+Phrasing should be "publicly and
+unambiguously derived from" and probably back in reference_wrapper too.  Updated
+wording supplied.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed wording.
+Move to NAD Editorial.
+
      
+
+
+
      Proposed resolution:
      
+
      
+(no changes to <functional> synopsis required)
+
      
+
+
      
+Change synopsis in Class template function 20.7.16.2 [func.wrap.func]:
+
      
+
+
      template<Returnable R, CopyConstructible... ArgTypes> 
+class function<R(ArgTypes...)> 
+  : public unary_function<T1, R>      // iff sizeof...(ArgTypes) == 1 and see below
+                                      // ArgTypes contains T1
+  : public binary_function<T1, T2, R> // iff sizeof...(ArgTypes) == 2 and see below
+                                      // ArgTypes contains T1 and T2
+{
+   ...
+
      
+
+
      
+Add new p1/p2 before 20.7.16.2.1 [func.wrap.func.con]:
+
      
+
+
      
+
      
+The template instantiation function<R(T1)> shall be publicly and
+unambiguously derived from 
+std::unary_function<T1,R> if and only if the template type parameter
+is a function type taking one argument of type T1 and returning R.
+
      
+
+
      
+The template instantiation function<R(T1,T2)> shall be publicly and
+unambiguously derived from 
+std::binary_function<T1,T2,R> if and only if the template type
+parameter is a function type taking two arguments of type T1 and T2 and
+returning R.
+
      
+
+
      explicit function();
+
      
+
      
+
+
+
+
+
+
+
      
+
      1024. Response to JP 39
      
+
      Section: 20.7.16.2 [func.wrap.func] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-16
      
+
      View all other issues in [func.wrap.func].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses JP 39
      
+
+
      
+There are no requires corresponding to F of std::function.
+
      
+
+
      [
+2009-05-01 Daniel adds:
+]
      
+
+
+
      
+1070 removes the second constructor.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+If issue 1070 is accepted,
+the changes to the second constructor
+in this issue are moot.
+
      
+
+
      [
+2009-07 Frankfurt:
+]
      
+
+
+
      
+Constructors have no definition.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Correct as follows in 20.7.16.2 [func.wrap.func] (class definition)
+
      
+
+
       template<class F, Allocator Alloc>
+   requires ConstructibleWithAllocator<F, Alloc>
+     && call=Callable<F, ArgTypes...>
+     && Convertible<call::result_type, R>
+   function(allocator_arg_t, const Alloc&, F);
+ template<class F, Allocator Alloc>
+   requires ConstructibleWithAllocator<F,Alloc>
+     && call=Callable<F, ArgTypes...>
+     && Convertible<call::result_type, R>
+   function(allocator_arg_t, const Alloc&, F&&);
+
      
+
+
+
+
+
+
+
      
+
      1025. Response to UK 208
      
+
      Section: 20.7.17 [unord.hash] Status: NAD Future
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
      
+
      View other active issues in [unord.hash].
      
+
      View all other issues in [unord.hash].
      
+
      View all issues with NAD Future status.
      
+
      Discussion:
      
+
+
      Addresses UK 208
      
+
+
      
+std::hash should be implemented for much more of the standard
+library. In particular for pair, tuple and all the
+standard containers.
+
      
+
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      1026. Response to UK 209
      
+
      Section: 20.8 [memory] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
      
+
      View all other issues in [memory].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses UK 209
      
+
+
      
+Smart pointers cannot be used in constrained templates.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+We look forward to a paper on this topic. We recommend no action until a
+paper is available. We understand that a paper is forthcoming.
+
      
+
+
      [
+Peter Dimov adds:
+]
      
+
+
+
      
+shared_ptr<T> and weak_ptr<T> support all
+types T for which T* is valid. In other words, a
+possible (partial) resolution is to change class T to
+PointeeType T for shared_ptr, weak_ptr and
+possibly enable_shared_from_this.
+
      
+
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      1027. Response to UK 213
      
+
      Section: 20.8.4 [default.allocator] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-15
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses UK 213
      
+
+
      
+std::allocator should be constrained to simplify its use on constrained
+contexts. This library component models allocation from free store via the
+new operator so choose constraints to 
+match. The Allocator concept allows for a wider variety of allocators that
+users may choose to supply if their allocation model does not require
+operator new, without impacting the 
+requirements of this template. 
+
      
+
+
      
+Suggested direction:
+
      
+
      
+The primary allocator template should be constrained to require
+ObjectType<T> and FreeStoreAllocatable<T>.
+Further operations to be constrained as required.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Agree as stated. A future paper will address additional related issues.
+
      
+
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      1028. Response to UK 214
      
+
      Section: 20.8.6 [storage.iterator] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-16
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses UK 214
      
+
+
      
+raw_storage_iterator needs constraining as an iterator adaptor to be safely
+used in constrained templates 
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+We look forward to a paper on this topic. We recommend no action until a
+paper is available.
+
      
+
+
      [
+Post Summit Alisdair provided wording and rationale.
+]
      
+
+
+
+
+
      Proposed resolution:
      
+
      
+20.8 [memory] p2
+
      
+
      
+Update the synopsis for <memory>
+
      
+
      // 20.7.8, raw storage iterator:
+template <class ForwardIterator OutputIterator, class ObjectType T> 
+  requires OutputIterator< OutIter, T >
+    class raw_storage_iterator;
+
+template <ForwardIterator OutIter, ObjectType T> 
+  requires OutputIterator< OutIter, T >
+  concept_map Iterator<raw_storage_iterator< OutIter, T > > { }
+
      
+
+
+
      
+20.8.6 [storage.iterator] p1
+
      
+
      
+Replace class template definition with:
+
      
+
      namespace std { 
+  template <class ForwardIterator OutputIterator, class ObjectType T> 
+    requires OutputIterator< OutIter, T >
+  class raw_storage_iterator 
+    : public iterator<output_iterator_tag,void,void,void,void> { 
+  public: 
+    explicit raw_storage_iterator(OutputIterator x); 
+
+    raw_storage_iterator<OutputIterator,T>& operator*(); 
+    raw_storage_iterator<OutputIterator,T>& operator=(const T& element); 
+    raw_storage_iterator<OutputIterator,T>& operator++(); 
+    raw_storage_iterator<OutputIterator,T> operator++(int); 
+  }; 
+
+  template <ForwardIterator OutIter, ObjectType T> 
+    requires OutputIterator< OutIter, T >
+    concept_map Iterator<raw_storage_iterator< OutIter, T > > { }
+}
+
      
+
+
+
      Rationale:
      
+
      
+raw_storage_iterator has to adapt a ForwardIterator,
+rather than just an InputIterator for two reasons:
+
      
+
+
        
+
      1. 
+The initial iterator passed by value is expected to remain valid,
+pointing to the initialized region of memory.
+
        2. 
+
      2. 
+to avoid breaking the declaration of post-increment operator which would
+require some kind of proxy formulation to support generalised InputIterators.
+
        3. 
+
      
+
+
+
+
+
+
+
      
+
      1029. Response to UK 210
      
+
      Section: 20.8.8 [specialized.algorithms] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-16
      
+
      View all other issues in [specialized.algorithms].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses UK 210
      
+
+
      Related to 582
      
+
+
      
+Specialized algorithms for memory managenment need requirements to be
+easily usable in constrained templates.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+We look forward to a paper on this topic. We recommend no action until a
+paper is available.
+
      
+
+
      [
+Post Summit Alisdair provided wording.
+]
      
+
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+
      
+Daniel adds:
+
      
+
+
      
+
        
+
      1. 
+I suggest Size should require IntegralLike and not UnsignedIntegralLike,
+because otherwise simple int-literals could not be provided as arguments
+and it would conflict with other algorithms that only require IntegralLike.
+
        2. 
+
      2. 
+
        
+The current for-loop-test relies on evaluation in boolean context which is
+not provided by ArithmeticLike and it's refinements. I propose to change the
+corresponding for-loop-headers to:
+
        
+
          
+
        1. 
+for uninitialized_copy_n: for ( ; n > Size(0); ++result, ++first, --n) {
+
          2. 
+
        2. 
+for uninitialized_fill_n: for (; n > Size(0); ++first, --n) {
+
          3. 
+
        
+
        3. 
+
      
+
      
+
+
      
+Alisdair adds:
+
      
+
      
+For the record I agree with Daniel's suggestion.
+
      
+
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+20.8 [memory] p2
+
      
+
      
+Update the synopsis for <memory>
+
      
+
      template <class InputIterator InIter,
+         class ForwardIterator OutputIterator<auto, InIter::reference> OutIter> 
+   requires ForwardIterator<OutIter>
+   ForwardIterator OutIter
+   uninitialized_copy(InputIterator InIter first, InputIterator InIter last, 
+                      ForwardIterator OutIter result);
+
+template <class InputIterator InIter,
+          class IntegralLike Size,
+          class ForwardIterator OutputIterator<auto, InIter::reference> OutIter> 
+  requires ForwardIterator<OutIter>
+  ForwardIterator OutIter
+  uninitialized_copy_n(InputIterator InIter first, Size n, 
+                       ForwardIterator OutIter result);
+
+template <class ForwardIterator Iter, class ObjectType T>
+  requires Constructible< Iter::value_type, const T& >
+  void uninitialized_fill(ForwardIterator Iter first, ForwardIterator Iter last, 
+                          const T& x);
+
+template <class ForwardIterator Iter, class IntegralLike Size, class ObjectType T> 
+  requires Constructible< Iter::value_type, const T& >
+  void
+  uninitialized_fill_n(ForwardIterator Iter first, Size n, const T& x);
+
      
+
+
      
+Update as follows:
+
      
+
+
      
+uninitialized_copy 20.8.8.2 [uninitialized.copy]
+
      
+
+
      template <class InputIterator InIter,
+         class ForwardIterator OutputIterator<auto, InIter::reference> OutIter> 
+   requires ForwardIterator<OutIter>
+   ForwardIterator OutIter
+   uninitialized_copy(InputIterator InIter first, InputIterator InIter last, 
+                      ForwardIterator OutIter result);
+
      
+
+
      
+
      
+-1- Effects:
+
      
+
      for (; first != last; ++result, ++first)  {
+   new (static_cast<void*>(&*result))
+       typename iterator_traits<ForwardIterator> OutIter::value_type(*first);
+}
+
      
+
+
      
+-2- Returns: result
+
      
+
+
      
+
+
      template <class InputIterator InIter,
+          class IntegralLike Size,
+          class ForwardIterator OutputIterator<auto, InIter::reference> OutIter> 
+  requires ForwardIterator<OutIter>
+  ForwardIterator OutIter
+  uninitialized_copy_n(InputIterator InIter first, Size n, 
+                       ForwardIterator OutIter result);
+
      
+
+
      
+
      
+-3- Effects:
+
      
+
      for ( ; n > Size(0); ++result, ++first, --n) {
+   new (static_cast<void*>(&*result))
+       typename iterator_traits<ForwardIterator> OutIter::value_type(*first);
+}
+
      
+
      
+-4- Returns: result
+
      
+
      
+
+
      
+
+
+
      
+uninitialized_fill 20.8.8.3 [uninitialized.fill]
+
      
+
+
      template <class ForwardIterator Iter, class ObjectType T>
+  requires Constructible< Iter::value_type, const T& >
+  void uninitialized_fill(ForwardIterator Iter first, ForwardIterator Iter last, 
+                          const T& x);
+
      
+
+
      
+
      
+-1- Effects:
+
      
+
      for (; first != last; ++first) {
+   new ( static_cast<void*>( &*first) ) 
+       typename iterator_traits<ForwardIterator> Iter::value_type(x);
+}
+
      
+
      
+
      
+
+
+
      
+uninitialized_fill_n 20.8.8.4 [uninitialized.fill.n]
+
      
+
+
      template <class ForwardIterator Iter, class IntegralLike Size, class ObjectType T> 
+  requires Constructible< Iter::value_type, const T& >
+  void
+  uninitialized_fill_n(ForwardIterator Iter first, Size n, const T& x);
+
      
+
+
      
+
      
+-1- Effects:
+
      
+
      for (; n-- > Size(0); ++first, --n) {
+   new ( static_cast<void*>( &*first) ) 
+       typename iterator_traits<ForwardIterator> Iter::value_type(x);
+}
+
      
+
      
+
      
+
+
+
+
+
+
+
      
+
      1032. Response to JP 45
      
+
      Section: 20.9 [time] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-16
      
+
      View all other issues in [time].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses JP 45
      
+
+
      
+Rep, Period, Clock and Duration
+don't correspond to concept.
+
      
+
      template <class Rep, class Period = ratio<1>> class duration; 
+template <class Clock, class Duration = typename Clock::duration> class time_point; 
+
      
+
      
+Make concept for Rep, Period, Clock and Duration.
+Fix 20.9 [time] and wait_until
+and wait_for's template parameter at 30 [thread]. 
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+We agree that this section needs concepts. We look forward to a paper on
+this topic. We recommend no action until a paper is available.
+
      
+
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      1036. Response to UK 231
      
+
      Section: 23.2.3 [sequence.reqmts] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-15
      
+
      View all other issues in [sequence.reqmts].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses UK 231
      
+
+
      
+p9-p11 are redundant now that Concepts define what it means to be an
+Iterator and guide overload resolution accordingly. 
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Agree with issue and change to 23.2.3 [sequence.reqmts]. The
+changes required to 21 [strings] will be part of the general
+concept support for that clause.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Strike 23.2.3 [sequence.reqmts]p9-11. Make sure std::basic_string
+has constraints similar to
+std::vector to meet this old guarantee. 
+
      
+
+
+
+
+
+
      
+
      1057. RandomNumberEngineAdaptor
      
+
      Section: 26.5 [rand] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-15
      
+
      View all other issues in [rand].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      
+The RandomNumberEngineAdaptor concept breaks precedent in the
+way the library has been specified by grouping requirements into a
+concept that is never actually used in the library.
+
      
+
      
+This is undoubtedly a very helpful device for documentation, but we are not
+comfortable with the precedent - especially as we have rejected national
+body comments on the same grounds.
+
      
+
      
+Suggest either removing the concept, or providing an algorithm/type that
+requires this concept in their definition (such as a factory function to
+create new engines).
+
      
+
      
+The preference is to create a single new algorithm and retain the value of
+the existing documentation.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+Walter points out that it is unlikely that any algorithm would ever
+require this concept, but that the concept nonetheless is useful as
+documentation, and (via concept maps) as a means of checking specific adapters.
+
      
+
      
+Alisdair disagrees as to the concept's value as documentation.
+
      
+
      
+Marc points out that the RandomNumberDistribution
+is also a concept not used elsewhere in the Standard.
+
      
+
      
+Pete agrees that a policy of not inventing concepts
+that aren't used in the Standard is a good starting point,
+but should not be used as a criterion for rejecting a concept.
+
      
+
      
+Move to Open.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      1058. New container issue
      
+
      Section: 23.2.3 [sequence.reqmts] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-13
      
+
      View all other issues in [sequence.reqmts].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
+
      
+Sequence containers 23.2.3 [sequence.reqmts]:
+
      
+
+
      
+The return value of new calls added to table 83 are not specified.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+We agree with the proposed resolution.
+
      
+
      
+Move to NAD Editorial.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+Add after p6 23.2.3 [sequence.reqmts]:
+
      
+
+
      
+
      
+-6- ...
+
      
+
      
+The iterator returned from a.insert(p,rv) points to the copy of rv
+inserted into a.
+
      
+
      
+The iterator returned from a.emplace(p, args) points to the new
+element constructed from args inserted into a.
+
      
+
      
+
+
+
+
+
+
      
+
      1059. Usage of no longer existing FunctionType concept
      
+
      Section: 20.7.16.2 [func.wrap.func] Status: NAD Concepts
+ Submitter: Daniel Krügler Opened: 2009-03-13  Last modified: 2009-07-16
      
+
      View all other issues in [func.wrap.func].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      
+Due to a deliberate core language decision, the earlier called
+"foundation" concept std::FunctionType had been removed in
+N2773
+shortly
+before the first "conceptualized" version of the WP
+(N2798)
+had been
+prepared. This caused a break of the library, which already used this
+concept in the adapted definition of std::function
+(20.7 [function.objects]/2, header <functional> synopsis and
+20.7.16.2 [func.wrap.func]).
+
      
+
      
+A simple fix would be to either (a) make std::function's primary template
+unconstrained or to (b) add constraints based on existing (support) concepts.
+A more advanced fix would (c) introduce a new library concept.
+
      
+
      
+The big disadvantage of (a) is, that users can define templates which
+cause compiler errors during instantiation time because of under-constrainedness
+and would thus violate the basic advantage of constrained
+code.
+
      
+
      
+For (b), the ideal constraints for std::function's template parameter would
+be one which excludes everything else but the single provided partial
+specialization that matches every "free function" type (i.e. any function
+type w/o cv-qualifier-seq and w/o ref-qualifier).
+Expressing such a type as as single requirement would be written as
+
      
+
      template<typename T>
+requires ReferentType<T> // Eliminate cv void and function types with cv-qual-seq
+                         //   or ref-qual (depending on core issue #749)
+      && PointeeType<T>  // Eliminate reference types
+      && !ObjectType<T>  // Eliminate object types
+
      
+
      
+Just for completeness approach (c), which would make sense, if the
+library has more reasons to constrain for free function types:
+
      
+
      auto concept FreeFunctionType<typename T>
+  : ReferentType<T>, PointeeType<T>, MemberPointeeType<T>
+{
+  requires !ObjectType<T>;
+}
+
      
+
      
+I mention that approach because I expect that free function types belong
+to the most natural type categories for every days coders. Potential
+candidates in the library are addressof and class template packaged_task.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+Alisdair would prefer to have a core-supported FunctionType concept
+in order that any future changes be automatically correct
+without need for a library solution to catch up;
+he points to type traits as a precedent.
+Further, he believes that a published concept can't in the future
+be changed.
+
      
+
      
+Bill feels this category of entity would change sufficiently slowly
+that he would be willing to take the risk.
+
      
+
      
+Of the discussed solutions, we tend toward option (c).
+We like the idea of having a complete taxonomy of native types,
+and perhaps erred in trimming the set.
+
      
+
      
+We would like to have this issue reviewed by Core and would like
+their feedback.  Move to Open.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
        
+
      1. 
+
        
+Change in 20.7 [function.objects]/2, Header <functional> synopsis:
+
        
+
        // 20.6.16 polymorphic function wrappers:
+class bad_function_call;
+template<FunctionTypeReferentType F>
+requires PointeeType<F> && !ObjectType<F>
+class function; // undefined
+
        
+
        2. 
+
      2. 
+
        
+Change in 20.7.16.2 [func.wrap.func]:
+
        
+
        namespace std {
+template<FunctionTypeReferentType F>
+requires PointeeType<F> && !ObjectType<F>
+class function; // undefined
+
        
+
        3. 
+
      
+
+
+
+
+
+
      
+
      1060. Embedded nulls in NTBS
      
+
      Section: 17.5.2.1.4.1 [byte.strings] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-03-13  Last modified: 2009-07-13
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
+
      
+Definition of null-terminated sequences allow for embedded nulls. This is
+surprising, and probably not supportable with the intended use cases.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the issue, but believe this can be handled editorially.
+Move to NAD Editorial.
+
      
+
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      1061. Bad indexing for tuple access to pair (Editorial?)
      
+
      Section: 20.3.4 [pair.astuple] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-03-13  Last modified: 2009-07-13
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
+
+
      
+The definition of get implies that get must return the second element if
+given a negative integer.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+Move to NAD Editorial.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+20.3.4 [pair.astuple] p5:
+
      
+
+
      template<int size_t I, class T1, class T2> 
+  requires True<(I < 2)> 
+  const P& get(const pair<T1, T2>&);
+
      
+
      
+
+
+
+
+
+
+
      
+
      1063. 03 iterator compatibilty
      
+
      Section: D.10.4 [iterator.backward] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-15  Last modified: 2009-07-16
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      
+Which header must a user #include to obtain the library-supplied
+concept_maps declared in this paragraph?
+
      
+
+
      
+This is important information, as existing user code will break if this
+header is not included, and we should make a point of mandating this header
+is #include-d by library headers likely to make use of it, notably
+<algorithm>.  See issue 1001 for more details.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the direction of the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
      [
+2009-07 Frankfurt
+]
      
+
+
+
      
+We believe this is NAD Concepts, but this needs to be reviewed against the
+post-remove-concepts draft.
+
      
+
+
+
      Proposed resolution:
      
+
      Change D.10 [depr.lib.iterator.primitives], Iterator primitives, as
+indicated:
      
+
+
      
+  
      To simplify the use of iterators and provide backward compatibility with
+  previous C++ Standard Libraries,
+  the library provides several classes and functions. Unless otherwise
+  specified, these classes and functions shall be defined in header <iterator>.
      
+
      
+
      Change D.10.4 [iterator.backward], Iterator backward compatibility, as
+indicated:
      
+
      
+  
      The library provides concept maps that allow iterators specified with
+  iterator_traits to interoperate with
+  algorithms that require iterator concepts. These concept maps shall be
+  defined in the same header that defines the iterator. [Example:
      
+
      
+
+
+
+
+
+
      
+
      1067. simplified wording for inner_product
      
+
      Section: 26.7 [numeric.ops] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-17  Last modified: 2009-07-14
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      
+One of the motivating examples for introducing requirements-aliases was to
+simplify the wording of the inner_product requirements.  As the paper
+adopting the feature and constrained wording for the library went through in
+the same meeting, it was not possible to make the change at the time.  The
+simpler form should be adopted now though.  Similarly, most the other
+numerical algorithms can benefit from a minor cleanup.
+
      
+
      
+Note that in each case, the second more generalised form of the algorithm
+does not benefit, as there are already named constraints supplied by the
+template type parameters.
+
      
+
+
      [
+2009-05-02 Daniel adds:
+]
      
+
+
+
      
+
      
+one part of the suggested resolution suggests the removal of the
+MoveConstructible<T> requirement from
+inner_product. According to 26.7.2 [inner.product]
+
      
+
+
      
+Computes its result by initializing the accumulator acc with the
+initial value init
+
      
+
+
      
+this step requires at least MoveConstructible.
+
      
+
+
      
+Therefore I strongly suggest to take this removal back (Note also
+that the corresponding overload with a functor argument still has
+the same MoveConstructible<T> requirement).
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+We agree with the proposed resolution as amended by Daniel's suggestion
+to restore MoveConstructible,
+reflected in the updated proposed resolution below.
+
      
+
      
+Move to Tentatively Ready.
+
      
+
      
+
 
-In addition, paragraph 1 of the same section makes use of a rather
-informal shorthand notation to specify sets of macros. When
-interpreted strictly, the notation specifies macros such
-as INT_8_MIN that are not intended to be specified.
+
      Proposed resolution:
      
+
      
+Change in 26.7 [numeric.ops] and  [accumulate]:
+
      
 
-   
      
+
      template <InputIterator Iter, MoveConstructible T>
+ requires add = HasPlus<T, Iter::reference>
+       && HasAssign<T, HasPlus<T, Iter::reference> add::result_type>
+ T accumulate(Iter first, Iter last, T init);
+
      
 
-Finally, the section is missing the usual table of symbols defined
-in that header, making it inconsistent with the rest of the
-specification.
+
      
+Change in 26.7 [numeric.ops] and 26.7.2 [inner.product]:
+
      
 
-   
      
- 
- 
      Proposed resolution:
      
-   
      
+
      template <InputIterator Iter1, InputIterator Iter2, MoveConstructible T>
+  requires mult = HasMultiply<Iter1::reference, Iter2::reference>
+        && add = HasPlus<T, HasMultiply<Iter1::reference, Iter2::reference> mult::result_type>
+        && HasAssign< 
+             T,
+             HasPlus<T,
+                     HasMultiply<Iter1::reference, Iter2::reference>::result_type> add::result_type>
+  T inner_product(Iter1 first1, Iter1 last1, Iter2 first2, T init);
+
      
 
-I propose to use the same approach in the C++ spec as C99 uses, that
-is, to specify the header synopsis in terms of "exposition only" types
-that make use of the symbol N to denote one or
-more of a theoretically unbounded set of widths.
+
      
+Change in 26.7 [numeric.ops] and 26.7.3 [partial.sum]:
+
      
 
-   
      
-   
      
+
      template <InputIterator InIter, OutputIterator<auto, const InIter::value_type&> OutIter>
+  requires add = HasPlus<InIter::value_type, InIter::reference>
+        && HasAssign<InIter::value_type,
+                     HasPlus<InIter::value_type, InIter::reference> add::result_type>
+        && Constructible<InIter::value_type, InIter::reference>
+  OutIter partial_sum(InIter first, InIter last, OutIter result);
+
      
 
-Further, I propose to add a new table to section listing the symbols
-defined in the header using a more formal notation that avoids
-introducing inconsistencies.
+
      
+Change in 26.7 [numeric.ops] and 26.7.4 [adjacent.difference]:
+
      
 
-   
      
-   
      
+
      template <InputIterator InIter, OutputIterator<auto, const InIter::value_type&> OutIter>
+  requires sub = HasMinus<InIter::value_type, InIter::value_type>
+        && Constructible<InIter::value_type, InIter::reference>
+        && OutputIterator<OutIter, HasMinus<InIter::value_type, InIter::value_type> sub::result_type>
+        && MoveAssignable<InIter::value_type>
+  OutIter adjacent_difference(InIter first, InIter last, OutIter result);
+
      
 
-To this effect, in  cstdint.syn
-Header <cstdint> synopsis, replace both the
-synopsis and paragraph 1 with the following text:
 
-   
      
-   
      
-     
      
-       
        
-         
      1. 
 
-In the names defined in the <cstdint> header, the
-symbol N represents a positive decimal integer
-with no leading zeros (e.g., 8 or 24, but not 0, 04, or 048). With the
-exception of exact-width types, macros and types for values
-of N in the set of 8, 16, 32, and 64 are
-required. Exact-width types, and any macros and types for values
-of N other than 8, 16, 32, and 64 are
-optional. However, if an implementation provides integer types with
-widths of 8, 16, 32, or 64 bits, the corresponding exact-width types
-and macros are required.
 
-         
        2. 
-       
      
-     
-     
      namespace std {
 
-   // required types
 
-   // Fastest minimum-width integer types
-   typedef signed integer type   int_fast8_t;
-   typedef signed integer type   int_fast16_t;
-   typedef signed integer type   int_fast32_t;
-   typedef signed integer type   int_fast64_t;
+
      
+
      1072. Is std::hash a constrained template or not?
      
+
      Section: 20.7.17 [unord.hash] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-19  Last modified: 2009-07-16
      
+
      View other active issues in [unord.hash].
      
+
      View all other issues in [unord.hash].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
 
-   typedef unsigned integer type uint_fast8_t;
-   typedef unsigned integer type uint_fast16_t;
-   typedef unsigned integer type uint_fast32_t;
-   typedef unsigned integer type uint_fast64_t;
+
      
+Is std::hash a constrained template or not?
+
      
+
      
+According to Class template hash 20.7.17 [unord.hash], the definition is:
+
      
 
-   // Minimum-width integer types
-   typedef signed integer type   int_least8_t;
-   typedef signed integer type   int_least16_t;
-   typedef signed integer type   int_least32_t;
-   typedef signed integer type   int_least64_t;
+
      template <class T>
+struct hash : public std::unary_function<T, std::size_t> {
+  std::size_t operator()(T val) const;
+};
+
      
 
-   typedef unsigned integer type uint_least8_t;
-   typedef unsigned integer type uint_least16_t;
-   typedef unsigned integer type uint_least32_t;
-   typedef unsigned integer type uint_least64_t;
+
      
+And so unconstrained.
+
      
+
      
+According to the <functional> synopsis in p2 Function objects
+20.7 [function.objects] the template is declared as:
+
      
 
-   // Greatest-width integer types
-   typedef signed integer type   intmax_t;
-   typedef unsigned integer type uintmax_t;
+
      template <ReferentType T> struct hash;
+
      
 
-   // optionally defined types
+
      
+which would make hash a constrained template.
+
      
 
-   // Exact-width integer types
-   typedef signed integer type   intN_t;
-   typedef unsigned integer type uintN_t;
+
      [
+2009-03-22 Daniel provided wording.
+]
      
 
-   // Fastest minimum-width integer types for values
-   // of N other than 8, 16, 32, and 64
-   typedef signed integer type   uint_fastN_t;
-   typedef unsigned integer type uint_fastN_t;
 
-   // Minimum-width integer types for values
-   // of N other than 8, 16, 32, and 64
-   typedef signed integer type   uint_leastN_t;
-   typedef unsigned integer type uint_leastN_t;
+
      [
+Batavia (2009-05):
+]
      
 
-   // Integer types capable of holding object pointers
-   typedef signed integer type   intptr_t;
-   typedef signed integer type   intptr_t;
+
      
+
      
+Alisdair is not certain that Daniel's proposed resolution is sufficient,
+and recommends we leave the hash template unconstrained for now.
+
      
+
      
+Recommend that the Project Editor make the constrained declaration consistent
+with the definition in order to make the Working Paper internally consistent,
+and that the issue then be revisited.
+
      
+
      
+Move to Open.
+
      
+
      
 
-}
      
-   
      
-   
      
 
-[Note to editor: Remove all of the existing paragraph 1 from  cstdint.syn.]
+
      Proposed resolution:
      
+
+
      
+[To the editor: This resolution is merge-compatible to the
+resolution of 1078]
+
      
+
+
        
+
      1. 
+
        
+In 20.7 [function.objects]/2, header <functional> synopsis, change as indicated:
+
        
+
+
        // 20.6.17, hash function base template:
+template <ReferentType T> struct hash; // undefined
+
        
+
        2. 
+
      2. 
+
        
+In 20.7.17 [unord.hash]/1 change as indicated:
+
        
+
        namespace std {
+ template <class T>
+ struct hash : public std::unary_function<T, std::size_t> {
+ std::size_t operator()(T val) const;
+ };
+ template <ReferentType T> struct hash; // undefined
+}
+
        
+
        3. 
+
      3. 
+
        
+In 20.7.17 [unord.hash]/2 change as indicated:
+
        
+
+
        
+-2-  For all library-provided specializations, the template
+instantiation hash<T>
+  shall provide a public operator() with return type std::size_t to
+satisfy the concept
+  requirement Callable<const hash<T>, const T&>. If T is an object
+type or reference to
+  object, hash<T> shall be publicly derived from
+std::unary_function<T, std::size_t>.
+   The return value of operator() is unspecified, except that
+equal arguments
+  shall yield the same result. operator() shall not throw exceptions.
+
        
+
        4. 
+
      4. 
+
        
+In 18.7 [support.rtti]/1, header <typeinfo> synopsis change as indicated:
+
        
+
        namespace std {
+  class type_info;
+  class type_index;
+  template <classReferentType T> struct hash;
+
        
+
        5. 
+
      
 
-   
      
-   
      
-     Table ??: Header <cstdint> synopsis
-     
-       
-         
-           
-           
-         
-       
-       
-         
-           
-           
-           
-           
-         
-         
-           
-           
-           
-         
-         
-           
-           
-           
-         
-         
-           
-           
-           
-         
-         
-           
-           
-           
-         
-         
-           
-           
-           
-         
-         
-           
-           
-           
-         
-         
-           
-           
-         
-         
-         
-           
-           
-           
-         
-         
-           
-           
-           
-         
-         
-           
-           
-           
-         
-         
-           
-           
-           
-           
-         
-         
-           
-           
-           
-         
-         
-           
-           
-           
-         
-         
-           
-           
-           
-         
-         
-           
-           
-           
-         
-       
-     
      TypeName(s)
      Macros:INTN_MININTN_MAXUINTN_MAX
      INT_FASTN_MININT_FASTN_MAXUINT_FASTN_MAX
      INT_LEASTN_MININT_LEASTN_MAXUINT_LEASTN_MAX
      INTPTR_MININTPTR_MAXUINTPTR_MAX
      INTMAX_MININTMAX_MAXUINTMAX_MAX
      PTRDIFF_MINPTRDIFF_MAXPTRDIFF_MAX
      SIG_ATOMIC_MINSIG_ATOMIC_MAXSIZE_MAX
      WCHAR_MINWCHAR_MAX
      WINT_MINWINT_MAX
      INTN_C()UINTN_C()
      INTMAX_C()UINTMAX_C()
      Types:intN_tuintN_t
      int_fastN_tuint_fastN_t
      int_leastN_tuint_leastN_t
      intptr_tuintptr_t
      intmax_tuintmax_t
      
-   
      
- 
 
 
 
 
 
      
-
      849. missing type traits to compute root class and derived class of types in a class hierachy
      
-
      Section: 20.6.7 [meta.trans.other] Status: NAD
- Submitter: Thorsten Ottosen Opened: 2008-06-05  Last modified: 2008-09-16
      
-
      View other active issues in [meta.trans.other].
      
-
      View all other issues in [meta.trans.other].
      
-
      View all issues with NAD status.
      
+
      1074. concept map broken by N2840
      
+
      Section: 20.8.3 [allocator.element.concepts] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-03-19  Last modified: 2009-07-13
      
+
      View all issues with NAD Concepts status.
      
 
      Discussion:
      
-
      
-The type traits library contains various traits to dealt with
-polymorphic types, e.g. std::has_virtual_destructor, std::is_polymorphic
-and std::is_base_of. However, there is no way to compute the unique
-public base class of a type  if such  one exists.  Such a trait could be
-very useful if one needs to instantiate a specialization made for the
-root class whenever a derived class is passed as parameter. For example,
-imagine that you wanted to specialize std::hash for a class
-hierarchy---instead of specializing each class, you could specialize the
-std::hash<root_class> and provide a partial specialization that worked
-for all derived classes.
-
      
 
 
      
-This ability---to specify operations in terms of their equivalent in the
-root class---can be done with e.g. normal functions, but there is,
-AFAIK, no way to do it for class templates. Being able to access
-compile-time information about the type-hierachy can be very powerful,
-and I therefore also suggest traits that computes the directly derived
-class whenever that is possible.
+p7 Allocator-related element concepts 20.8.3 [allocator.element.concepts]
 
      
 
 
      
-If the computation can not be done, the traits should fall back on an
-identity transformation. I expect this gives the best overall usability.
+The changes to the AllocatableElement concept mean this concept_map
+specialization no longer matches the original concept:
 
      
 
+
      template <Allocator Alloc, class T, class ... Args>
+  requires HasConstructor<T, Args...>
+    concept_map AllocatableElement<Alloc, T, Args&&...> {
+      void construct_element(Alloc& a, T* t, Args&&... args) {
+        Alloc::rebind<T>(a).construct(t, forward(args)...);
+      }
+    }
+
      
 
-
      Proposed resolution:
      
-
      
-Add the following to the synopsis in 20.6.2 [meta.type.synop] under "other transformations":
-
      
+
      [
+2009-03-23 Pablo adds:
+]
      
 
-
      template< class T > struct direct_base_class;
-template< class T > struct direct_derived_class;
-template< class T > struct root_base_class;
-
      
 
+
      
+Actually, this is incorrect,
+N2840
+says. "In section 
+20.8.3 [allocator.element.concepts] paragraph 8, modify the definition of the
+AllocatableElement concept and eliminate the related concept map:" but
+then neglects to include the red-lined text of the concept map that was
+to be eliminated. Pete also missed this, but I caught it he asked me to
+review his edits.  Pete's updated WP removes the concept map entirely,
+which was the original intent.  The issue is, therefore, moot.  Note, as
+per my presentation of
+N2840
+in summit, construct() no longer has a
+default implementation.  This regrettable fact was deemed (by David
+Abrahams, Doug, and myself) to be preferable to the complexity of
+providing a default implementation that would not under-constrain a more
+restrictive allocator (like the scoped allocators).
+
      
+
+
      [
+2009-05-01 Daniel adds:
+]
      
+
+
      
 
      
-Add three new entries to table 51 (20.6.7 [meta.trans.other]) with the following content
+it seems to me that #1074 should be resolved as a NAD, because the
+current WP has already removed the previous AllocatableElement concept map.
+It introduced auto concept AllocatableElement instead, but as of
+20.8.3 [allocator.element.concepts]/7 this guy contains now
 
      
+
      requires FreeStoreAllocatable<T>;
+void Alloc::construct(T*, Args&&...);
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
 
 
      
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
      TemplateConditionComments
      template< class T > struct direct_base_class;T shall be a complete type.The member typedef type shall equal the accessible unambiguous direct base class of T.
-If no such type exists, the member typedef type shall equal T.
      template< class T > struct direct_derived_class;T shall be a complete type.The member typedef type shall equal the unambiguous type which has T
-as an accessible unambiguous direct base class. If no such type exists, the member typedef
-type shall equal T.
      template< class T > struct root_base_class;T shall be a complete type.The member typedef type shall equal the accessible unambiguous most indirect base class of
-T. If no such type exists, the member typedef type shall equal T.
      
+
      
+The affected code is no longer part of the Working Draft.
+
      
+
      
+Move to NAD.
+
      
 
      
 
 
+
      Proposed resolution:
      
+
      
+Change 20.8.3 [allocator.element.concepts]:
+
      
+
+
      template <Allocator Alloc, class T, class ... Args>
+  requires HasConstructor<T, Args...>
+    concept_map AllocatableElement<Alloc, T, Args&&...> {
+      void construct_element(Alloc& a, T* t, Args&&... args) {
+        Alloc::rebind<T>(a).construct(t, forward(args)...);
+      }
+    }
+
      
 
-
      Rationale:
      
-2008-9-16 San Francisco:  Issue pulled by author prior to being reviewed by the LWG.
 
 
 
 
 
 
      
-
      855. capacity() and reserve() for deque?
      
-
      Section: 23.3.2.2 [deque.capacity] Status: NAD
- Submitter: Hervé Brönnimann Opened: 2008-06-11  Last modified: 2008-09-22
      
-
      View all other issues in [deque.capacity].
      
-
      View all issues with NAD status.
      
+
      1077. Nonesense tuple declarations
      
+
      Section: 20.5.2 [tuple.tuple] Status: NAD Editorial
+ Submitter: Pete Becker Opened: 2009-03-20  Last modified: 2009-07-13
      
+
      View all other issues in [tuple.tuple].
      
+
      View all issues with NAD Editorial status.
      
 
      Discussion:
      
 
      
-The main point is that capacity can be viewed as a mechanism to  
-guarantee the validity of iterators when only push_back/pop_back
-operations are used.  For vector, this goes with reallocation.  For  
-deque, this is a bit more subtle:  capacity() of a deque may shrink,  
-whereas that of vector doesn't.   In a circular buffer impl. of the  
-map, as Howard did, there is very similar notion of capacity: as long  
-as size() is less than B * (total size of the map - 2), it is  
-guaranteed that no iterator is invalidated after any number of  
-push_front/back and pop_front/back operations.  But this does not  
-hold for other implementations.
+Class template tuple 20.5.2 [tuple.tuple]:
 
      
+
+
      template <class... UTypes>
+  requires Constructible<Types, const UTypes&>...
+template <class... UTypes>
+  requires Constructible<Types, RvalueOf<UTypes>::type>...
+
      
+
 
      
-Still, I believe, capacity() can be defined by size() +  how many  
-push_front/back minus pop_front/back that can be performed before  
-terators are invalidated.  In a classical impl., capacity() = size()
-+  the min distance to either "physical" end of the deque (i.e.,  
-counting the empty space in the last block plus all the blocks until  
-the end of the map of block pointers).  In Howard's circular buffer  
-impl., capacity() = B * (total size of the map - 2) still works with  
-this definition, even though the guarantee could be made stronger.
+Somebody needs to look at this and say what it should be.
 
      
+
+
      [
+2009-03-21 Daniel provided wording.
+]
      
+
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+The resolution looks correct; move to NAD Editorial.
+
      
+
+
+
      Proposed resolution:
      
 
      
-A simple picture of a deque:
+In 20.5.2 [tuple.tuple], class tuple, change as indicated:
 
      
-
      A-----|----|-----|---F+|++++|++B--|-----|-----Z
+
+
      template <class... UTypes>
+  requires Constructible<Types, const UTypes&>...
+  tuple(const pair<UTypes...>&);
+template <class... UTypes>
+  requires Constructible<Types, RvalueOf<UTypes>::type>...
+  tuple(pair<UTypes...>&&);
 
      
+
 
      
-(A,Z mark the beginning/end, | the block boundaries, F=front, B=back,  
-and - are uninitialized, + are initialized)
-In that picture:  capacity = size() + min(dist(A,F),dist(B,Z)) = min 
-(dist(A,B),dist(F,Z)).
+[NB.: The corresponding prototypes do already exist in 20.5.2.1 [tuple.cnstr]/7+8]
 
      
+
+
+
+
+
+
      
+
      1078. DE-17: Remove class type_index
      
+
      Section: 18.7.2 [type.index] Status: NAD Concepts
+ Submitter: Doug Gregor Opened: 2009-03-20  Last modified: 2009-07-16
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
+
      Addresses DE 17
      
+
 
      
-Reserve(n) can grow the map of pointers and add possibly a number of  
-empty blocks to it, in order to guarantee that the next n-size()
-push_back/push_front operations will not invalidate iterators, and  
-also will not allocate (i.e. cannot throw).  The second guarantee is  
-not essential and can be left as a QoI.  I know well enough existing  
-implementations of deque (sgi/stl, roguewave, stlport, and  
-dinkumware) to know that either can be implemented with no change to  
-the existing class layout and code, and only a few modifications if  
-blocks are pre-allocated (instead of always allocating a new block,  
-check if the next entry in the map of block pointers is not zero).
+DE-17: 
 
      
 
      
-Due to the difference with vector, wording is crucial.  Here's a  
-proposed wording to make things concrete;  I tried to be reasonably  
-careful but please double-check me:
+The class type_index should be removed; it provides no additional
+functionality beyond providing appropriate concept maps.
 
      
 
 
      [
-San Francisco:
+2009-03-31 Peter adds:
 ]
      
 
 
 
      
 
      
-Hans: should the Returns clause for capacity read "1 Returns: A lower
-bound..." rather than "1 Returns: An upper bound..."
+It is not true, in principle, that std::type_index provides no  utility
+compared to bare std::type_info*.
 
      
 
      
-Howard: maybe what's needed is capacity_front and capacity_back. In
-fact, I think I implemented a deque that had these members as
-implementation details.
+std::type_index can avoid the lifetime issues with type_info when  the
+DLL that has produced the type_info object is unloaded. A raw
+type_info* does not, and cannot, provide any protection in this  case.
+A type_index can (if the implementor so chooses) because it  can wrap a
+smart (counted or even cloning) pointer to the type_info  data that is
+needed for name() and before() to work.
 
      
 
      
 
 
 
 
      Proposed resolution:
      
+
      Modify the header <typeinfo> synopsis in 
+  18.7 [support.rtti]p1 as follows:
      
 
-
      
-Add new signatures to synopsis in 23.3.2 [deque]:
-
      
-
-
      size_type capacity() const;
-bool reserve(size_type n);
+
      namespace std { 
+  class type_info; 
+  class type_index;
+  template <class T> struct hash;
+  template<> struct hash<type_indexconst type_info *> : public std::unary_function<type_indexconst type_info *, size_t> {
+    size_t operator()(type_indexconst type_info * indext) const;
+  };
+  concept_map LessThanComparable<const type_info *> see below
+  class bad_cast; 
+  class bad_typeid;
+}
 
      
 
+
      Add the following new subsection
      
+
      
 
      
-Add new signatures to 23.3.2.2 [deque.capacity]:
-
      
+18.7.1.1 Template specialization hash<const type_info *>
+[type.info.hash]
      
 
-
      
-
      size_type capacity() const;
+
      size_t operator()(const type_info *x) const;
 
      
-
      
+
        
+
      1. Returns: x->hash_code()
        2. 
+
      
+
      
+
+ 
      Add the following new subsection
      
+ 
      
+
      18.7.1.2 type_info concept map [type.info.concepts]
      
+
+
+
      concept_map LessThanComparable<const type_info *> {
+  bool operator<(const type_info *x, const type_info *y) { return x->before(*y); }
+  bool operator<=(const type_info *x, const type_info *y) { return !y->before(*x); }
+  bool operator>(const type_info *x, const type_info *y) { return y->before(*x); }
+  bool operator>=(const type_info *x, const type_info *y) { return !x->before(*y); }
+}
+
      
+
        
+  
      1. Note: provides a well-defined ordering among
+  type_info const pointers, which makes such pointers
+  usable in associative containers (23.4).
        2. 
+
      
+
      
+
+
      Remove section 18.7.2 [type.index]
      
+
+
+
+
+
+
      
+
      1080. Concept ArithmeticLike should provide explicit boolean  conversion
      
+
      Section: 20.2.13 [concept.arithmetic] Status: NAD Concepts
+ Submitter: Daniel Krügler Opened: 2009-03-21  Last modified: 2009-07-15
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
 
      
-1 Returns: An upper bound on n + max(n_f - m_f, n_b - m_b)  such  
-that, for any sequence of n_f push_front, m_f pop_front, n_b  
-push_back, and m_b pop_back operations, interleaved in any order,  
-starting with the current deque of size n, the deque does not  
-invalidate any of its iterators except to the erased elements.
+Astonishingly, the current concept ArithmeticLike as specified in
+20.2.13 [concept.arithmetic] does not provide explicit conversion
+to bool although this is a common property of arithmetic types
+(4.12 [conv.bool]). Recent proposals that introduced such types
+(integers of arbitrary precision,
+n2143,
+decimals
+n2732
+indirectly
+via conversion to long long) also took care of such a feature.
 
      
 
      
-2 Remarks:  Unlike a vector's capacity, the capacity of a deque can  
-decrease after a sequence of insertions at both ends, even if none of  
-the operations caused the deque to invalidate any of its iterators  
-except to the erased elements.
+Adding such an explicit conversion associated function would also
+partly solve a currently invalid effects clause in library, which bases
+on this property, 24.2.6 [random.access.iterators]/2:
 
      
-
      
-
      
+
      { difference_type m = n;
+ if (m >= 0) while (m--) ++r;
+ else while (m++) --r;
+ return r; }
+
      
 
-
      
-
      bool reserve(size_type n);
-
      
-
      
 
      
-2 Effects: A directive that informs a deque of a planned sequence of  
-push_front, pop_front, push_back, and pop_back operations, so that it  
-can manage iterator invalidation accordingly. After reserve(),  
-capacity() is greater or equal to the argument of reserve if this  
-operation returns true; and equal to the previous value of capacity()
-otherwise.  If an exception is thrown, there are no effects.
+Both while-loops take advantage of a contextual conversion to bool
+(Another problem is that the >= comparison uses the no
+longer supported existing implicit conversion from int to IntegralLike).
 
      
+
+Original proposed resolution:
+
        
+
      1. 
 
        
-3 Returns: true if iterators are invalidated as a result of this  
-operation, and false otherwise.
+In 20.2.13 [concept.arithmetic], add to the list of less refined
+concepts one further concept:
 
        
+
+
        concept ArithmeticLike<typename T>
+  : Regular<T>, LessThanComparable<T>, HasUnaryPlus<T>, HasNegate<T>,
+    HasPlus<T, T>, HasMinus<T, T>, HasMultiply<T, T>, HasDivide<T, T>,
+    HasPreincrement<T>, HasPostincrement<T>, HasPredecrement<T>,
+    HasPostdecrement<T>,
+    HasPlusAssign<T, const T&>, HasMinusAssign<T, const T&>,
+    HasMultiplyAssign<T, const T&>,
+    HasDivideAssign<T, const T&>, ExplicitlyConvertible<T, bool> {
+
        
+
        2. 
+
      2. 
 
        
-4 Complexity: It does not change the size of the sequence and takes  
-at most linear time in n.
+In 24.2.6 [random.access.iterators]/2 change the current effects clause
+as indicated [The proposed insertion fixes the problem that the previous
+implicit construction from integrals has been changed to an explicit
+constructor]:
 
        
+
        { difference_type m = n;
+ if (m >= difference_type(0)) while (m--) ++r;
+ else while (m++) --r;
+ return r; }
+
        
+
        3. 
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
 
      
-5 Throws: length_error if n > max_size().
+We agree that arithmetic types ought be convertible to bool,
+and we therefore agree with the proposed resolution's paragraph 1.
 
      
 
      
-6 Remarks: It is guaranteed that no invalidation takes place during a  
-sequence of insert or erase operations at either end that happens  
-after a call to reserve() except to the erased elements, until the  
-time when an insertion would make max(n_f-m_f, n_b-m_b) larger than  
-capacity(), where n_f is the number of push_front, m_f of pop_front,  
-n_b of push_back, and m_b of pop_back operations since the call to  
-reserve().
+We do not agree that the cited effects clause is invalid,
+as it expresses intent rather than specific code.
 
      
 
      
-7        An implementation is free to pre-allocate buffers so as to  
-offer the additional guarantee that no exception will be thrown  
-during such a sequence other than by the element constructors.
+Move to Review, pending input from concepts experts.
 
      
 
      
-
      
 
-
      
-And 23.3.2.3 [deque.modifiers] para 1, can be enhanced:
-
      
 
-
      
-1 Effects: An insertion in the middle of the deque invalidates all the iterators and references to elements of the
-deque. An insertion at either end of the deque invalidates all the iterators to the deque,
-unless provisions have been made with reserve,
-but has no effect on the validity of references to elements of the deque.
-
      
 
+
      Proposed resolution:
      
+
      
+In 20.2.13 [concept.arithmetic], add to the list of less refined
+concepts one further concept:
+
      
 
-
      Rationale:
      
-Complication outweighs the benefit.
+
      concept ArithmeticLike<typename T>
+  : Regular<T>, LessThanComparable<T>, HasUnaryPlus<T>, HasNegate<T>,
+    HasPlus<T, T>, HasMinus<T, T>, HasMultiply<T, T>, HasDivide<T, T>,
+    HasPreincrement<T>, HasPostincrement<T>, HasPredecrement<T>,
+    HasPostdecrement<T>,
+    HasPlusAssign<T, const T&>, HasMinusAssign<T, const T&>,
+    HasMultiplyAssign<T, const T&>,
+    HasDivideAssign<T, const T&>, ExplicitlyConvertible<T, bool> {
+
      
 
 
 
 
 
 
      
-
      864. Defect in atomic wording
      
-
      Section: 29.6 [atomics.types.operations] Status: NAD Editorial
- Submitter: Anthony Williams Opened: 2008-07-10  Last modified: 2008-09-17
      
-
      View all other issues in [atomics.types.operations].
      
-
      View all issues with NAD Editorial status.
      
+
      1081. Response to UK 216
      
+
      Section: 21 [strings] Status: NAD Concepts
+ Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-07-15
      
+
      View all other issues in [strings].
      
+
      View all issues with NAD Concepts status.
      
 
      Discussion:
      
-
      
-There's an error in 29.6 [atomics.types.operations]/p9:
-
      
+
      Addresses UK 216, JP 46, JP 48
      
 
-
      
-
      C atomic_load(const volatile A * object);
-C atomic_load_explicit(const volatile A * object, memory_order);
-C A ::load(memory_order order = memory_order_seq_cst) const volatile;
-
      
-
      
 
      
-Requires: The order argument shall not be memory_order_acquire nor
-memory_order_acq_rel.
+All the containers use concepts for their iterator usage, exect for
+basic_string. This needs fixing.
 
      
-
      
-
      
 
 
      
-I believe that this should state
+Use concepts for iterator template parameters throughout the chapter.
 
      
-
      
-shall not be memory_order_release.
-
      
 
-
      
-There's also an error in 29.6 [atomics.types.operations]/p17:
-
      
+
      [
+Summit:
+]
      
 
 
      
-... When only one memory_order argument is supplied, the value of success
-is order, and
-the value of failure is order except that a value of
-memory_order_acq_rel shall be replaced by the value
-memory_order_require ...
+NB comments to be handled by Dave Abrahams and Howard Hinnant with
+advice from PJP: UK216 (which duplicates) JP46, JP48. JP46 supplies
+extensive proposed wording; start there.
 
      
+
+
+
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      1082. Response to JP 49
      
+
      Section: 22 [localization] Status: NAD Concepts
+ Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-07-15
      
+
      View all other issues in [localization].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      Addresses JP 49
      
+
 
      
-I believe this should state
+codecvt does not use concept. For example, create CodeConvert
+concept and change as follows.
 
      
+
+
      template<CodeConvert Codecvt, class Elem = wchar_t>
+  class wstring_convert {
+
      
+
+
      [
+Summit:
+]
      
+
 
      
-shall be replaced by the value memory_order_acquire ...
+To be handled by Howard Hinnant, Dave Abrahams, Martin Sebor, PJ Plauger.
 
      
 
 
 
      Proposed resolution:
      
+
+
+
+
+
+
      
+
      1083. Response to JP 52, 53
      
+
      Section: 22 [localization] Status: NAD Concepts
+ Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-07-15
      
+
      View all other issues in [localization].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      Addresses JP 52, JP 53
      
+
 
      
-Change 29.6 [atomics.types.operations]/p9:
+InputIterator does not use concept.
 
      
 
-
      
-
      C atomic_load(const volatile A * object);
-C atomic_load_explicit(const volatile A * object, memory_order);
-C A ::load(memory_order order = memory_order_seq_cst) const volatile;
-
      
-
      
 
      
-Requires: The order argument shall not be memory_order_acquire
-memory_order_release nor memory_order_acq_rel.
+OutputIterator does not use concept.
 
      
-
      
-
      
 
 
      
-Change 29.6 [atomics.types.operations]/p17:
+Comments include proposed wording.
 
      
 
+
      [
+Summit:
+]
      
+
 
      
-... When only one memory_order argument is supplied, the value of success
-is order, and
-the value of failure is order except that a value of
-memory_order_acq_rel shall be replaced by the value
-memory_order_require memory_order_acquire ...
+To be handled by Howard Hinnant, Dave Abrahams, Martin Sebor, PJ Plauger.
 
      
 
 
-
-
      Rationale:
      
-Already fixed by the time the LWG processed it.
+
      Proposed resolution:
      
 
 
 
 
 
 
      
-
      870. Do unordered containers not support function pointers for predicate/hasher?
      
-
      Section: 23.2.5 [unord.req] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2008-08-17  Last modified: 2008-09-22
      
-
      View other active issues in [unord.req].
      
-
      View all other issues in [unord.req].
      
-
      View all issues with NAD Editorial status.
      
+
      1084. Response to UK 250
      
+
      Section: 24.2.4 [forward.iterators] Status: NAD Concepts
+ Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-07-16
      
+
      View all other issues in [forward.iterators].
      
+
      View all issues with NAD Concepts status.
      
 
      Discussion:
      
+
      Addresses UK 250
      
+
 
      
-Good ol' associative containers allow both function pointers and
-function objects as feasible
-comparators, as described in 23.2.4 [associative.reqmts]/2:
+A default implementation should be supplied for the post-increment
+operator to simplify implementation of iterators by users.
 
      
 
-
      
-Each associative container is parameterized on Key and an ordering
-relation Compare that
-induces a strict weak ordering (25.3) on elements of Key. [..]. The
-object of type Compare is
-called the comparison object of a container. This comparison object
-may be a pointer to
-function or an object of a type with an appropriate function call operator.[..]
-
      
-
 
      
-The corresponding wording for unordered containers is not so clear,
-but I read it to disallow
-function pointers for the hasher and I miss a clear statement for the
-equality predicate, see
-23.2.5 [unord.req]/3+4+5:
+Copy the Effects clause into the concept description as the default
+implementation. Assumes a default value for postincrement_result
 
      
 
+
      [
+Summit:
+]
      
+
 
      
-
      
-Each unordered associative container is parameterized by Key, by a
-function object Hash that
-acts as a hash function for values of type Key, and by a binary
-predicate Pred that induces an
-equivalence relation on values of type Key.[..]
-
      
-
      
-A hash function is a function object that takes a single argument of
-type Key and returns a
-value of type std::size_t.
-
      
-
      
-Two values k1 and k2 of type Key are considered equal if the
-container's equality function object
-returns true when passed those values.[..]
-
      
+Howard will open an issue.
 
      
 
-
      
-and table 97 says in the column "assertion...post-condition" for the
-expression X::hasher:
-
      
+
      [
+2009-06-07 Daniel adds:
+]
      
+
 
 
      
-Hash shall be a unary function object type such that the expression
-hf(k) has type std::size_t.
+This issue cannot currently be resolved as suggested, because
+that would render auto-detection of the return type
+postincrement_result invalid, see 14.10.2.2 [concept.map.assoc]/4+5. The
+best fix would be to add a default type to that associated type, but
+unfortunately any default type will prevent auto-deduction of types of
+associated functions as quoted above. A corresponding core issue
+is in preparation.
 
      
 
-
      
-Note that 20.7 [function.objects]/1 defines as "Function objects are
-objects with an operator() defined.[..]"
-
      
-
      
-Does this restriction exist by design or is it an oversight? If an
-oversight, I suggest that to apply
-the following
-
      
-
 
 
      Proposed resolution:
      
-
      
-In 23.2.5 [unord.req]/3, just after the second sentence which is written as
-
      
+
      [
+This wording assumes the acceptance of UK 251 / 1009.  Both
+wordings change the same paragraphs.
+]
      
 
-
      
-Additionally, unordered_map and unordered_multimap associate an
-arbitrary mapped type T with the Key.
-
      
 
 
      
-add one further sentence:
+Change 24.2.4 [forward.iterators]:
 
      
 
 
      
-Both Hash and Pred may be pointers to function or objects of a type
-with an appropriate function call operator.
-
      
+
      concept ForwardIterator<typename X> : InputIterator<X>, Regular<X> { 
+
+  MoveConstructible postincrement_result;
+  requires HasDereference<postincrement_result>
+        && Convertible<HasDereference<postincrement_result>::result_type, const value_type&>;
+
+  postincrement_result operator++(X& r, int); {
+     X tmp = r;
+     ++r;
+     return tmp;
+  }
+
+  axiom MultiPass(X a, X b) { 
+    if (a == b) *a == *b; 
+    if (a == b) ++a == ++b; 
+  } 
+}
+
      
+
+
+
+
+
+
+
      
+
      1085. Response to UK 258
      
+
      Section: 24.2.5 [bidirectional.iterators] Status: NAD Concepts
+ Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-07-16
      
+
      View all other issues in [bidirectional.iterators].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      Addresses UK 258
      
 
 
      
-[Note1: Since the detailed requirements for Pred and Hash are given in
-p.4 and p.5, it an alternative resolution
-would be to insert a new paragraph just after p.5, which contains the
-above proposed sentence]
+A default implementation should be supplied for the post-decrement
+operator to simplify implementation of iterators by users.
 
      
+
 
      
-[Note2: I do not propose a change of above quoted element in table 97,
-because the mis-usage of the
-notion of "function object" seems already present in the standard at
-several places, even if it includes
-function pointers, see e.g. 25 [algorithms]/7. The important point is
-that in those places a statement is
-given that the actually used symbol, like "Predicate" applies for
-function pointers as well]
+Copy the Effects clause into the concept description as the default
+implementation. Assumes a default value for postincrement_result
 
      
 
+
      [
+Summit:
+]
      
+
+
      
+Howard will open an issue.
+
      
 
-
      Rationale:
      
 
      [
-San Francisco:
+2009-06-07 Daniel adds:
 ]
      
 
 
 
      
-This is fixed by
-N2776.
+This issue cannot currently be resolved as suggested, because
+that would render auto-detection of the return type
+postdecrement_result invalid, see 1084.
 
      
 
 
+
      Proposed resolution:
      
+
+
      
+Change 24.2.5 [bidirectional.iterators]:
+
      
+
+
      
+
      concept BidirectionalIterator<typename X> : ForwardIterator<X> { 
+  MoveConstructible postdecrement_result; 
+  requires HasDereference<postdecrement_result> 
+        && Convertible<HasDereference<postdecrement_result>::result_type, const value_type&> 
+        && Convertible<postdecrement_result, const X&>; 
+  X& operator--(X&); 
+  postdecrement_result operator--(X& r, int); {
+     X tmp = r;
+     --r;
+     return tmp;
+  }
+}
+
      
+
+
 
 
 
 
 
      
-
      871. Iota's requirements on T are too strong
      
-
      Section: 26.7.5 [numeric.iota] Status: NAD
- Submitter: Daniel Krügler Opened: 2008-08-20  Last modified: 2008-09-23
      
-
      View all issues with NAD status.
      
+
      1086. Response to UK 284
      
+
      Section: 24.6 [stream.iterators] Status: NAD Concepts
+ Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-07-15
      
+
      View all issues with NAD Concepts status.
      
 
      Discussion:
      
+
      Addresses UK 284
      
+
 
      
-According to the recent WP
-N2691,
-26.7.5 [numeric.iota]/1, the requires clause
-of std::iota says:
+The stream iterators need constraining with concepts/requrires clauses.
 
      
 
+
      [
+Summit:
+]
      
+
 
      
-T shall meet the requirements of CopyConstructible and Assignable types, and
-shall be convertible to ForwardIterator's value type.[..]
+We agree. To be handled by Howard, Martin and PJ.
 
      
 
-
      
-Neither CopyConstructible nor Assignable is needed, instead MoveConstructible
-seems to be the correct choice. I guess the current wording resulted as an
-artifact from comparing it with similar numerical algorithms like accumulate.
-
      
 
-
      
-Note: If this function will be conceptualized, the here proposed
-MoveConstructible
-requirement can be removed, because this is an implied requirement of
-function arguments, see
-N2710/[temp.req.impl]/3, last bullet.
-
      
+
      Proposed resolution:
      
 
 
 
-
      Proposed resolution:
      
 
-
      
-Change the first sentence of 26.7.5 [numeric.iota]/1:
-
      
 
-
      
-Requires: T shall meet the requirements of
-CopyConstructible and Assignable types,
-
-be MoveConstructible (Table 34)
-
-and shall be
-convertible to ForwardIterator's value type. [..]
-
      
+
      
+
      1087. Response to UK 301
      
+
      Section: 25.4.5 [alg.replace] Status: NAD Concepts
+ Submitter: Howard Hinnant Opened: 2009-03-22  Last modified: 2009-07-15
      
+
      View all other issues in [alg.replace].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      Addresses UK 301
      
 
+
      
+replace and replace_if have the requirement: OutputIterator<Iter,
+Iter::reference> Which implies they need to copy some values in the
+range the algorithm is iterating over. This is not however the case, the
+only thing that happens is const T&s might be copied over existing
+elements (hence the OutputIterator<Iter, const T&>.
+
      
 
+
      
+Remove OutputIterator<Iter, Iter::reference> from replace
+and replace_if.
+
      
 
-
      Rationale:
      
 
      [
-post San Francisco:
+Summit:
 ]
      
 
-
 
      
-Issue pulled by author prior to review.
+We agree. To be handled by Howard.
 
      
 
 
+
      Proposed resolution:
      
+
      
+Change in 25.2 [algorithms.syn] and 25.4.5 [alg.replace]:
+
      
+
+
      template<ForwardIterator Iter, class T> 
+  requires OutputIterator<Iter, Iter::reference> 
+        && OutputIterator<Iter, const T&> 
+        && HasEqualTo<Iter::value_type, T> 
+  void replace(Iter first, Iter last, 
+               const T& old_value, const T& new_value); 
+
+template<ForwardIterator Iter, Predicate<auto, Iter::value_type> Pred, class T> 
+  requires OutputIterator<Iter, Iter::reference> 
+        && OutputIterator<Iter, const T&> 
+        && CopyConstructible<Pred> 
+  void replace_if(Iter first, Iter last,
+                  Pred pred, const T& new_value);
+
      
+
 
 
 
 
 
      
-
      872. move_iterator::operator[] has wrong return type
      
-
      Section: 24.5.3.2.12 [move.iter.op.index] Status: NAD Editorial
- Submitter: Doug Gregor Opened: 2008-08-21  Last modified: 2008-09-22
      
-
      View all issues with NAD Editorial status.
      
+
      1092. Class template integral_constant should be a  constrained template
      
+
      Section: 20.6.3 [meta.help] Status: NAD Concepts
+ Submitter: Daniel Krügler Opened: 2009-03-22  Last modified: 2009-07-15
      
+
      View all other issues in [meta.help].
      
+
      View all issues with NAD Concepts status.
      
 
      Discussion:
      
 
      
-move_iterator's operator[] is declared as:
+A first step to change the type traits predicates to constrained templates is to
+constrain their common base template integral_constant. This can be done,
+without enforcing depending classes to be constrained as well, but not
+vice versa
+without brute force late_check usages. The following proposed resolution depends
+on the resolution of LWG issue 1019.
 
      
 
-
      reference operator[](difference_type n) const;
-
      
+
      [
+Batavia (2009-05):
+]
      
 
-
      
-This has the same problem that reverse_iterator's operator[] used to
-have: if the underlying iterator's operator[] returns a proxy, the
-implicit conversion to value_type&& could end up referencing a temporary
-that has already been destroyed. This is essentially the same issue that
-we dealt with for reverse_iterator in DR 386.
-
      
+
      
+Move to Open, pending a paper that looks at constraints
+for the entirety of the type traits
+and their relationship to the foundation concepts.
+We recommend this be deferred
+until after the next Committee Draft is issued.
+
      
 
 
 
      Proposed resolution:
      
+
        
+
      1. 
 
        
-In 24.5.3.1 [move.iterator] and 24.5.3.2.12 [move.iter.op.index], change the declaration of
-move_iterator's operator[] to:
+In 20.6.2 [meta.type.synop], Header <type_traits>
+synopsis change as indicated:
 
        
-
-
        reference unspecified operator[](difference_type n) const;
+
        namespace std {
+// 20.5.3, helper class:
+template <classIntegralConstantExpressionType T, T v> struct integral_constant;
+
        
+
        2. 
+
      2. 
+
        
+In 20.6.3 [meta.help] change as indicated:
+
        
+
        template <classIntegralConstantExpressionType T, T v>
+struct integral_constant {
+  static constexpr T value = v;
+  typedef T value_type;
+  typedef integral_constant<T,v> type;
+  constexpr operator value_type() { return value; }
+};
 
        
+
        3. 
+
      
 
 
 
-
      Rationale:
      
+
+
+
      
+
      1096. unconstrained rvalue ref parameters
      
+
      Section: 17 [library] Status: NAD Concepts
+ Submitter: David Abrahams Opened: 2009-03-21  Last modified: 2009-07-16
      
+
      View other active issues in [library].
      
+
      View all other issues in [library].
      
+
      View all issues with NAD Concepts status.
      
+
      Discussion:
      
+
      
+TODO: Look at all cases of unconstrained rvalue ref parameters and check
+that concept req'ts work when T deduced as reference.
+
      
+
+
      
+ We found some instances where that was not done correctly and we figure
+   the possibility of deducing T to be an lvalue reference was probably
+   overlooked elsewhere.
+
      
+
 
      [
-San Francisco:
+Batavia (2009-05):
 ]
      
 
-
 
      
-NAD Editorial, see
-N2777.
+Move to Open, pending proposed wording from Dave for further review.
 
      
 
 
+
      Proposed resolution:
      
+
      
+
      
+
+
+
 
 
 
      
-
      874. Missing initializer_list constructor for discrete_distribution
      
-
      Section: 26.5.8.5.1 [rand.dist.samp.discrete] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2008-08-22  Last modified: 2009-03-09
      
-
      View all other issues in [rand.dist.samp.discrete].
      
+
      1101. unique requirements
      
+
      Section: 25.4.9 [alg.unique] Status: NAD Editorial
+ Submitter: Howard Hinnant Opened: 2009-04-25  Last modified: 2009-07-13
      
+
      View all other issues in [alg.unique].
      
 
      View all issues with NAD Editorial status.
      
 
      Discussion:
      
-
      
-During the Sophia Antipolis meeting it was decided to separate from 793 a
-subrequest that adds initializer list support to
-discrete_distribution, specifically,
-the issue proposed to add a c'tor taking a initializer_list<double>.
+
      
+From Message c++std-core-14160 Howard wrote:
 
      
 
+
      
+It was the intent of the rvalue reference proposal for unique to only require MoveAssignable:
+N1860.
+
      
 
+
      
+And Pete replied:
+
      
+
+
      
+That was overridden by the subsequent changes made for concepts in
+N2573,
+which reimposed the C++03 requirements.
+
      
 
-
      Proposed resolution:
      
-
        
-
      1. 
 
        
-In 26.5.8.5.1 [rand.dist.samp.discrete]/1, class discrete_distribution,
-just before the member declaration
+My impression is that this overwrite was a simple (unintentional) mistake.
+Wording below to correct it.
 
        
 
-
        explicit discrete_distribution(const param_type& parm);
-
        
+
        [
+Batavia (2009-05):
+]
        
 
+
        
 
        
-insert
+Howard notes this issue resolves a discrepancy between the synopsis
+and the description.
+
        
+
        
+Move to NAD Editorial.
 
        
+
        
 
-
        discrete_distribution(initializer_list<double> wl);
-
        
-
        2. 
 
-
      2. 
+
        Proposed resolution:
        
 
        
-Between p.4 and p.5 of the same section insert a new
-paragraph as part of the new member description:
+Change 25.4.9 [alg.unique]:
 
        
 
-
        discrete_distribution(initializer_list<double> wl);
-
        
+
        template<ForwardIterator Iter> 
+  requires OutputIterator<Iter, RvalueOf<Iter::reference>::type> 
+        && EqualityComparable<Iter::value_type> 
+  Iter unique(Iter first, Iter last); 
 
-
        
-Effects: Same as discrete_distribution(wl.begin(), wl.end()).
-
        
-
        
-
        3. 
-
      
+template<ForwardIterator Iter, EquivalenceRelation<auto, Iter::value_type> Pred> 
+  requires OutputIterator<Iter, RvalueOf<Iter::reference>::type> 
+        && CopyConstructible<Pred> 
+  Iter unique(Iter first, Iter last, Pred pred);
+
      
 
+
      
+Note that the synopsis in 25.2 [algorithms.syn] is already correct.
+
      
 
-
      Rationale:
      
-Addressed by
-N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
 
 
 
 
 
 
      
-
      875. Missing initializer_list constructor for piecewise_constant_distribution
      
-
      Section: 26.5.8.5.2 [rand.dist.samp.pconst] Status: NAD Editorial
- Submitter: Daniel Krügler Opened: 2008-08-22  Last modified: 2009-03-09
      
-
      View all other issues in [rand.dist.samp.pconst].
      
-
      View all issues with NAD Editorial status.
      
+
      1105. Shouldn't Range be an auto concept
      
+
      Section: 24.2.8 [iterator.concepts.range] Status: NAD Concepts
+ Submitter: David Abrahams Opened: 2009-04-23  Last modified: 2009-07-15
      
+
      View all issues with NAD Concepts status.
      
 
      Discussion:
      
-
      
-During the Sophia Antipolis meeting it was decided to separate from
-794 a subrequest that adds initializer list support to
-piecewise_constant_distribution, specifically, the issue proposed
-to add a c'tor taking a initializer_list<double> and a Callable to evaluate
-weight values. For consistency with the remainder of this class and
-the remainder of the initializer_list-aware library the author decided to
-change the list argument type to the template parameter RealType
-instead. For the reasoning to use Func instead of Func&& as c'tor
-function argument see issue 793.
-
      
 
+
      [
+2009-04-26 Herb adds:
+]
      
 
-
      Proposed resolution:
      
-
      Non-concept version of the proposed resolution
      
 
-
        
-
      1. 
+
        
 
        
-In 26.5.8.5.2 [rand.dist.samp.pconst]/1, class piecewise_constant_distribution,
-just before the member declaration
+Here's a common example: We have many ISV customers who have built lots of
+in-house STL-like containers. Imagine that, for the past ten years, the user
+has been happily using his XYZCorpContainer<T> that has begin() and end()
+and an iterator typedef, and indeed satisfies nearly all of Container,
+though maybe not quite all just like valarray. The user upgrades to a
+range-enabled version of a library, and now lib_algo( xyz.begin(), xyz.end());
+no longer works -- compiler error.
 
        
+
        
+Even though XYZCorpContainer matches the pre-conceptized version of the
+algorithm, and has been working for years, it appears the user has to write
+at least this:
+
        
+
        template<class T> concept_map Range<XYZCorpContainer<T>> {};
 
-
        explicit piecewise_constant_distribution(const param_type& parm);
+template<class T> concept_map Range<const XYZCorpContainer<T>> {};
 
        
-
 
        
-insert
+Is that correct?
+
        
+
        
+But he may actually have to write this as we do for initializer list:
 
        
+
        template<class T>
+concept_map Range<XYZCorpContainer<T>> {
+   typedef T* iterator;
+   iterator begin(XYZCorpContainer<T> c) { return c.begin(); }
+   iterator end(XYZCorpContainer<T> c) { return c.end(); }
+};
 
-
        template<typename Func>
-piecewise_constant_distribution(initializer_list<RealType> bl, Func fw);
+template<class T>
+concept_map Range<const XYZCorpContainer<T>> {
+   typedef T* iterator;
+   iterator begin(XYZCorpContainer<T> c) { return c.begin(); }
+   iterator end(XYZCorpContainer<T> c) { return c.end(); }
+};
 
        
-
        2. 
 
-
      2. 
-
        
-Between p.4 and p.5 of the same section insert a series of
-new paragraphs nominated below as [p5_1], [p5_2], and [p5_3]
-as part of the new member description:
-
        
+
      
 
-
      template<typename Func>
-piecewise_constant_distribution(initializer_list<RealType> bl, Func fw);
-
      
+
      [
+2009-04-28 Alisdair adds:
+]
      
 
-
      
 
+
      
 
      
-[p5_1] Complexity: Exactly nf = max(bl.size(), 1) - 1 invocations of fw.
+I recommend NAD, although remain concerned about header organisation.
 
      
-
 
      
-[p5_2] Requires:
+A user container will satisfy the MemberContainer concept, which IS auto.
+There is a concept_map for all MemberContainers to Container, and then a
+further concept_map for all Container to Range, so the stated problem is not
+actually true.  User defined containers will automatically match the Range
+concept without explicitly declaring a concept_map.
+
      
+
      
+The problem is that they should now provide an additional two headers,
+<iterator_concepts> and <container_concepts>.
+ The only difference from
+making Range an auto concept would be this reduces to a single header,
+<iterator_concepts>.
+
      
+
      
+I am strongly in favour of any resolution that tackles the issue of
+explicitly requiring concept headers to make these concept maps available.
 
      
+
      
 
-
        
-
      1. 
-fw shall be callable with one argument of type RealType, and shall
-   return values of a type convertible to double;
-
        2. 
-
      2. 
-The relation 0 < S = w0+. . .+wn-1 shall hold. 
-For all sampled values xk defined below, fw(xk) shall return a weight
-   value wk that is non-negative, non-NaN, and non-infinity;
-
        3. 
-
      3. 
-If nf > 0 let bk = *(bl.begin() + k), k = 0, . . . , bl.size()-1 and the
-following relations shall hold for k = 0, . . . , nf-1: bk < bk+1.
-
        4. 
-
      
+
      [
+Batavia (2009-05):
+]
      
 
+
      
 
      
-[p5_3] Effects:
+We observe there is a recent paper by Bjarne that overlaps this issue.
+
      
+
      
+Alisdair continues to recommend NAD.
+
      
+
      
+Move to Open, and recommend the issue be deferred until after the next
+Committee Draft is issued.
 
      
+
      
 
-
        
-
      1. 
-
        If nf == 0,
        
-
          
-
        1. 
-lets the sequence w have length n = 1 and consist of the single
-     value w0 = 1, and
-
          2. 
-
        2. 
-lets the sequence b have length n+1 with b0 = 0 and b1 = 1.
-
          3. 
-
        
-
        2. 
 
-
      2. 
-
        Otherwise,
        
-
          
-
        1. 
-sets n = nf, and [bl.begin(), bl.end()) shall form the sequence b of
-length n+1, and
-
          2. 
-
        2. 
-
          lets the sequences w have length n and for each k = 0, . . . ,n-1,
-     calculates:
          
-
          xk = 0.5*(bk+1 + bk)
-wk = fw(xk)
-
          
-
          3. 
-
        
-
        3. 
+
        Proposed resolution:
        
 
-
      3. 
-
        
-Constructs a piecewise_constant_distribution object with
-the above computed sequence b as the interval boundaries
-and with the probability densities:
-
        
-
        ρk = wk/(S * (bk+1 - bk)) for k = 0, . . . , n-1.
-
        
 
-
        4. 
-
      
 
-
      
-
      
-
      2. 
-
    
 
-
    Concept version of the proposed resolution
    
 
-
      
-
    1. 
+
      
+
      1107. constructor shared_future(unique_future) by value?
      
+
      Section: 30.6.6 [future.shared_future] Status: NAD Editorial
+ Submitter: Thomas J. Gritzan Opened: 2009-04-03  Last modified: 2009-07-13
      
+
      View other active issues in [future.shared_future].
      
+
      View all other issues in [future.shared_future].
      
+
      View all issues with NAD Editorial status.
      
+
      Discussion:
      
 
      
-In 26.5.8.5.2 [rand.dist.samp.pconst]/1, class piecewise_constant_distribution,
-just before the member declaration
+In the shared_future class definition in 30.6.6 [future.shared_future]
+the move constructor 
+that constructs a shared_future from an unique_future receives the 
+parameter by value. In paragraph 3, the same constructor receives it as 
+const value. 
 
      
 
-
      explicit piecewise_constant_distribution(const param_type& parm);
-
      
-
 
      
-insert
+I think that is a mistake and the constructor should take a r-value 
+reference: 
 
      
 
-
      template<Callable<auto, RealType> Func>
- requires Convertible<Func::result_type, double>
-piecewise_constant_distribution(initializer_list<RealType> bl, Func fw);
+
      shared_future(unique_future<R>&& rhs);
 
      
-
      2. 
 
-
    2. 
+
      [
+Batavia (2009-05):
+]
      
+
+
      
 
      
-Between p.4 and p.5 of the same section insert a series of
-new paragraphs nominated below as [p5_1], [p5_2], and [p5_3]
-as part of the new member description:
+We agree with the proposed resolution.
+
      
+
      
+Move to Tentatively Ready.
 
      
+
      
+
+
      [
+2009-07-05 Daniel notes:
+]
      
 
-
      template<Callable<auto, RealType> Func>
- requires Convertible<Func::result_type, double>
-piecewise_constant_distribution(initializer_list<RealType> bl, Func fw);
-
      
 
 
      
+The proposed change has already been incorported into the current working draft
+N2914.
+
      
 
-
      
-[p5_1] Complexity: Exactly nf = max(bl.size(), 1) - 1 invocations of fw.
-
      
 
+
      Proposed resolution:
      
 
      
-[p5_2] Requires:
+Change the synopsis in 30.6.6 [future.shared_future]:
 
      
 
-
        
-
      1. 
-The relation 0 < S = w0+. . .+wn-1 shall hold. 
-For all sampled values xk defined below, fw(xk) shall return a weight
-   value wk that is non-negative, non-NaN, and non-infinity;
-
        2. 
-
      2. 
-If nf > 0 let bk = *(bl.begin() + k), k = 0, . . . , bl.size()-1 and the
-following relations shall hold for k = 0, . . . , nf-1: bk < bk+1.
-
        3. 
-
      
+
      shared_future(unique_future<R>&& rhs);
+
      
 
 
      
-[p5_3] Effects:
+Change the definition of the constructor in 30.6.6 [future.shared_future]:
 
      
 
-
        
-
      1. 
-
        If nf == 0,
        
-
          
-
        1. 
-lets the sequence w have length n = 1 and consist of the single
-     value w0 = 1, and
-
          2. 
-
        2. 
-lets the sequence b have length n+1 with b0 = 0 and b1 = 1.
-
          3. 
-
        
-
        2. 
-
-
      2. 
-
        Otherwise,
        
-
          
-
        1. 
-sets n = nf, and [bl.begin(), bl.end()) shall form the sequence b of
-length n+1, and
-
          2. 
-
        2. 
-
          lets the sequences w have length n and for each k = 0, . . . ,n-1,
-     calculates:
          
-
          xk = 0.5*(bk+1 + bk)
-wk = fw(xk)
+
          shared_future(const unique_future<R>&& rhs);
 
          
-
          3. 
-
        
-
        3. 
 
-
      3. 
+
+
+
+
+
+
        
+
        1109. std::includes should require CopyConstructible predicate
        
+
        Section: 25.5.5.1 [includes] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-04-28  Last modified: 2009-07-13
        
+
        View all other issues in [includes].
        
+
        View all issues with NAD Concepts status.
        
+
        Discussion:
        
 
        
-Constructs a piecewise_constant_distribution object with
-the above computed sequence b as the interval boundaries
-and with the probability densities:
+All the set operation algorithms require a CopyConstructible predicate, with
+the exception of std::includes.  This looks like a typo as much as anything,
+given the general library requirement that predicates are copy
+constructible, and wording style of other set-like operations.
 
        
-
        ρk = wk/(S * (bk+1 - bk)) for k = 0, . . . , n-1.
-
        
 
-
        4. 
-
      
+
      [
+Batavia (2009-05):
+]
      
 
+
      
+We agree with the proposed resolution.
+Move to NAD Editorial.
 
      
-
      
-
      3. 
-
    
 
 
+
    Proposed resolution:
    
+
    
+Change 25.2 [algorithms.syn] and 25.5.5.1 [includes]:
+
    
 
-
    Rationale:
    
-Addressed by
-N2836 "Wording Tweaks for Concept-enabled Random Number Generation in C++0X".
+
    template<InputIterator Iter1, InputIterator Iter2,
+         typename CopyConstructible Compare>
+  requires Predicate<Compare, Iter1::value_type, Iter2::value_type>
+        && Predicate<Compare, Iter2::value_type, Iter1::value_type>
+  bool includes(Iter1 first1, Iter1 last1,
+                Iter2 first2, Iter2 last2,
+                Compare comp);
+
    
 
 
 
 
 
 
    
-
    892. Forward_list issues...
    
-
    Section: 23.3.3.5 [forwardlist.ops] Status: NAD Editorial
- Submitter: Ed Smith-Rowland Opened: 2008-09-15  Last modified: 2009-03-09
    
-
    View other active issues in [forwardlist.ops].
    
-
    View all other issues in [forwardlist.ops].
    
-
    View all issues with NAD Editorial status.
    
+
    1111. associative containers underconstrained
    
+
    Section: 23.4 [associative] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-04-29  Last modified: 2009-07-16
    
+
    View all other issues in [associative].
    
+
    View all issues with NAD Concepts status.
    
 
    Discussion:
    
 
    
-I was looking at the latest draft on forward_list.  Especially the splice methods.
+According to table 87 (n2857) the expression X::key_equal for an unordered
+container shall return a value of type Pred, where Pred is an equivalence
+relation.
 
    
+
 
    
-The first one splices a whole list after a given iterator in this.  The name is splice_after.
-I think in 23.3.3.5 [forwardlist.ops] paragraph 40
-change:
+However, all 4 containers constrain Pred to be merely a Predicate,
+and not EquivalenceRelation.
 
    
+
+
    [
+Batavia (2009-05):
+]
    
+
 
    
-Effect: Insert the contents of x before after position, ...
+
    
+We agree with the proposed resolution.
+
    
+
    
+Move to Review.
+
    
 
    
 
+
+
    Proposed resolution:
    
 
    
-A deeper issue involves the complexity.  forward_list has no size and we
-don't know when we've reached the end except to walk up to it.  To
-splice we would need to hook the end of the source list to the item
-after position in this list.  This would involve walking length of the
-source list until we got to the last dereference-able element in source.
-There's no way we could do this in O(1) unless we stored a bogus end in
-forward_list.
+For ordered containers, replace 
 
    
+
    Predicate<auto, Key, Key> Compare = less<Key>
+
    
 
    
-OTOH, the last version of splice_after with iterator ranges we could do
-in O(1) because we know how to hook the end of the source range to ...
+with 
 
    
+
    StrictWeakOrder<auto, Key, Key> Compare = less<Key>
+
    
+
 
    
-Unless I'm misconceiving the whole thing.  Which is possible.  I'll look at it again.
+For unordered containers, replace 
 
    
+
    Predicate<auto, Key, Key> Compare = less<Key>
+
    
 
    
-I'm pretty sure about the first part though.
+with 
+
    
+
    EquivalenceRelation<auto, Key, Key> Compare = less<Key>
+
    
+
    
+As in the following declarations:
 
    
-
-
    [
-San Francisco:
-]
    
-
 
 
    
 
    
-This issue is more complicated than it looks.
+Associative containers 23.4 [associative]
 
    
 
    
-paragraph 47: replace each (first, last) with (first, last]
+ 1 Headers <map> and <set>:
 
    
 
    
-add a statement after paragraph 48 that complexity is O(1)
+   Header <map> synopsis
 
    
+
       namespace std {
+     template <ValueType Key, ValueType T,
+               PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
+               Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
+       requires NothrowDestructible<Key> && NothrowDestructible<T>
+             && CopyConstructible<Compare>
+             && AllocatableElement<Alloc, Compare, const Compare&>
+             && AllocatableElement<Alloc, Compare, Compare&&>
+     class map;
+
+     ...
+
+     template <ValueType Key, ValueType T,
+               PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
+               Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
+       requires NothrowDestructible<Key> && NothrowDestructible<T>
+             && CopyConstructible<Compare>
+             && AllocatableElement<Alloc, Compare, const Compare&>
+             && AllocatableElement<Alloc, Compare, Compare&&>
+     class multimap;
+
+     ...
+
+   }
+
    
+
 
    
-remove the complexity statement from the first overload of splice_after
+   Header <set> synopsis
 
    
+
       namespace std {
+     template <ValueType Key, PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
+               Allocator Alloc = allocator<Key> >
+       requires NothrowDestructible<Key> && CopyConstructible<Compare>
+             && AllocatableElement<Alloc, Compare, const Compare&>
+             && AllocatableElement<Alloc, Compare, Compare&&>
+     class set;
+
+     ...
+
+     template <ValueType Key, PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
+               Allocator Alloc = allocator<Key> >
+       requires NothrowDestructible<Key> && CopyConstructible<Compare>
+             && AllocatableElement<Alloc, Compare, const Compare&>
+             && AllocatableElement<Alloc, Compare, Compare&&>
+     class multiset;
+
+     ...
+
+   }
+
    
+
 
    
-We may have the same problems with other modifiers, like erase_after.
-Should it require that all iterators in the range (position, last] be
-dereferenceable?
+ 23.4.1p2 Class template map [map]
 
    
+
     namespace std {
+   template <ValueType Key, ValueType T,
+             PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
+             Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
+     requires NothrowDestructible<Key> && NothrowDestructible<T>
+           && CopyConstructible<Compare>
+           && AllocatableElement<Alloc, Compare, const Compare&>
+           && AllocatableElement<Alloc, Compare, Compare&&>
+   class map {
+     ...
+   };
+ }
+
    
+
+
 
    
-We do, however, like the proposed changes and consider them Editorial.
-Move to NAD Editorial, Pending. Howard to open a new issue to handle the
-problems with the complexity requirements.
+ 23.4.2p2 Class template multimap [multimap]
 
    
+
     namespace std {
+   template <ValueType Key, ValueType T,
+             PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
+             Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
+     requires NothrowDestructible<Key> && NothrowDestructible<T>
+           && CopyConstructible<Compare>
+           && AllocatableElement<Alloc, Compare, const Compare&>
+           && AllocatableElement<Alloc, Compare, Compare&&>
+   class multimap {
+     ...
+   };
+ }
+
    
+
+
 
    
-Opened 897.
+ 23.4.3p2 Class template set [set]
 
    
-
    
+
     namespace std {
+   template <ValueType Key, PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
+             Allocator Alloc = allocator<Key> >
+     requires NothrowDestructible<Key> && CopyConstructible<Compare>
+           && AllocatableElement<Alloc, Compare, const Compare&>
+           && AllocatableElement<Alloc, Compare, Compare&&>
+   class set {
+     ...
+   };
+ }
+
    
 
 
-
    Proposed resolution:
    
 
    
-In 23.3.3.5 [forwardlist.ops] paragraph 40
-change:
+ 23.4.4p2 Class template multiset [multiset]
 
    
-
    
-Effect: Insert the contents of x before after position, ...
+
     namespace std {
+   template <ValueType Key, PredicateStrictWeakOrder<auto, Key, Key> Compare = less<Key>,
+             Allocator Alloc = allocator<Key> >
+     requires NothrowDestructible<Key> && CopyConstructible<Compare>
+           && AllocatableElement<Alloc, Compare, const Compare&>
+           && AllocatableElement<Alloc, Compare, Compare&&>
+   class multiset {
+     ...
+   };
+ }
+
    
+
+
    
+ 23.5 Unordered associative containers [unord]
+
    
+
    
+ 1 Headers <unordered_map> and <unordered_set>:
+
    
+
    
+ Header <unordered_map> synopsis
+
    
+
     namespace std {
+   // 23.5.1, class template unordered_map:
+   template <ValueType Key,
+             ValueType T,
+             Callable<auto, const Key&> Hash = hash<Key>,
+             PredicateEquivalenceRelation<auto, Key, Key> Pred = equal_to<Key>,
+             Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
+     requires NothrowDestructible<Key> && NothrowDestructible<T>
+           && SameType<Hash::result_type, size_t>
+           && CopyConstructible<Hash> && CopyConstructible<Pred>
+           && AllocatableElement<Alloc, Pred, const Pred&>
+           && AllocatableElement<Alloc, Pred, Pred&&>
+           && AllocatableElement<Alloc, Hash, const Hash&>
+           && AllocatableElement<Alloc, Hash, Hash&&>
+     class unordered_map;
+
+   // 23.5.2, class template unordered_multimap:
+   template <ValueType Key,
+             ValueType T,
+             Callable<auto, const Key&> Hash = hash<Key>,
+             PredicateEquivalenceRelation<auto, Key, Key> Pred = equal_to<Key>,
+             Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
+     requires NothrowDestructible<Key> && NothrowDestructible<T>
+           && SameType<Hash::result_type, size_t>
+           && CopyConstructible<Hash> && CopyConstructible<Pred>
+           && AllocatableElement<Alloc, Pred, const Pred&>
+           && AllocatableElement<Alloc, Pred, Pred&&>
+           && AllocatableElement<Alloc, Hash, const Hash&>
+           && AllocatableElement<Alloc, Hash, Hash&&>
+     class unordered_multimap;
+
+   ...
+ }
+
    
+
+
    
+ Header <unordered_set> synopsis
+
    
+
     namespace std {
+   // 23.5.3, class template unordered_set:
+   template <ValueType Value,
+             Callable<auto, const Value&> Hash = hash<Value>,
+             PredicateEquivalenceRelation<auto, Value, Value> class Pred = equal_to<Value>,
+             Allocator Alloc = allocator<Value> >
+     requires NothrowDestructible<Value>
+           && SameType<Hash::result_type, size_t>
+           && CopyConstructible<Hash> && CopyConstructible<Pred>
+           && AllocatableElement<Alloc, Pred, const Pred&>
+           && AllocatableElement<Alloc, Pred, Pred&&>
+           && AllocatableElement<Alloc, Hash, const Hash&>
+           && AllocatableElement<Alloc, Hash, Hash&&>
+     class unordered_set;
+
+   // 23.5.4, class template unordered_multiset:
+   template <ValueType Value,
+             Callable<auto, const Value&> Hash = hash<Value>,
+             PredicateEquivalenceRelation<auto, Value, Value> class Pred = equal_to<Value>,
+             Allocator Alloc = allocator<Value> >
+     requires NothrowDestructible<Value>
+           && SameType<Hash::result_type, size_t>
+           && CopyConstructible<Hash> && CopyConstructible<Pred>
+           && AllocatableElement<Alloc, Pred, const Pred&>
+           && AllocatableElement<Alloc, Pred, Pred&&>
+           && AllocatableElement<Alloc, Hash, const Hash&>
+           && AllocatableElement<Alloc, Hash, Hash&&>
+     class unordered_multiset;
+
+   ...
+ }
+
    
+
+
    
+ 23.5.1p3 Class template unordered_map [unord.map]
+
    
+
     namespace std {
+   template <ValueType Key,
+             ValueType T,
+             Callable<auto, const Key&> Hash = hash<Key>,
+             PredicateEquivalenceRelation<auto, Key, Key> Pred = equal_to<Key>,
+             Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
+     requires NothrowDestructible<Key> && NothrowDestructible<T>
+           && SameType<Hash::result_type, size_t>
+           && CopyConstructible<Hash> && CopyConstructible<Pred>
+           && AllocatableElement<Alloc, Pred, const Pred&>
+           && AllocatableElement<Alloc, Pred, Pred&&>
+           && AllocatableElement<Alloc, Hash, const Hash&>
+           && AllocatableElement<Alloc, Hash, Hash&&>
+   class unordered_map
+   {
+     ...
+   };
+ }
+
    
+
+
    
+ 23.5.2p3 Class template unordered_multimap [unord.multimap]
+
    
+
     namespace std {
+   template <ValueType Key,
+             ValueType T,
+             Callable<auto, const Key&> Hash = hash<Key>,
+             PredicateEquivalenceRelation<auto, Key, Key> Pred = equal_to<Key>,
+             Allocator Alloc = allocator<pair&lt;<b>const Key, T> > >
+     requires NothrowDestructible<Key> && NothrowDestructible<T>
+           && SameType<Hash::result_type, size_t>
+           && CopyConstructible<Hash> && CopyConstructible<Pred>
+           && AllocatableElement<Alloc, Pred, const Pred&>
+           && AllocatableElement<Alloc, Pred, Pred&&>
+           && AllocatableElement<Alloc, Hash, const Hash&>
+           && AllocatableElement<Alloc, Hash, Hash&&>
+   class unordered_multimap
+   {
+     ...
+   };
+ }
+
    
+
+
    
+ 23.5.3p3 Class template unordered_set [unord.set]
+
    
+
     namespace std {
+   template <ValueType Value,
+             Callable<auto, const Value&> Hash = hash<Value>,
+             PredicateEquivalenceRelation<auto, Value, Value> class Pred = equal_to<Value>,
+             Allocator Alloc = allocator<Value> >
+     requires NothrowDestructible<Value>
+           && SameType<Hash::result_type, size_t>
+           && CopyConstructible<Hash> && CopyConstructible<Pred>
+           && AllocatableElement<Alloc, Pred, const Pred&>
+           && AllocatableElement<Alloc, Pred, Pred&&>
+           && AllocatableElement<Alloc, Hash, const Hash&>
+           && AllocatableElement<Alloc, Hash, Hash&&>
+   class unordered_set
+   {
+     ...
+   };
+ }
+
    
+
    
+ 23.5.4p3 Class template unordered_multiset [unord.multiset]
+
    
+
     namespace std {
+   template <ValueType Value,
+             Callable<auto, const Value&> Hash = hash<Value>,
+             PredicateEquivalenceRelation<auto, Value, Value> class Pred = equal_to<Value>,
+             Allocator Alloc = allocator<Value> >
+     requires NothrowDestructible<Value>
+           && SameType<Hash::result_type, size_t>
+           && CopyConstructible<Hash> && CopyConstructible<Pred>
+           && AllocatableElement<Alloc, Pred, const Pred&>
+           && AllocatableElement<Alloc, Pred, Pred&&>
+           && AllocatableElement<Alloc, Hash, const Hash&>
+           && AllocatableElement<Alloc, Hash, Hash&&>
+   class unordered_multiset
+   {
+     ...
+   };
+ }
+
    
+
 
    
 
 
 
 
 
+
 
    
-
    905. Mutex specification questions
    
-
    Section: 30.4.1.1 [thread.mutex.class] Status: Dup
- Submitter: Herb Sutter Opened: 2008-09-18  Last modified: 2009-03-22
    
-
    View other active issues in [thread.mutex.class].
    
-
    View all other issues in [thread.mutex.class].
    
-
    View all issues with Dup status.
    
-
    Duplicate of: 893
    
+
    1124.  Invalid definition of concept RvalueOf
    
+
    Section: 20.2.1 [concept.transform] Status: NAD Concepts
+ Submitter: Daniel Krügler Opened: 2009-05-28  Last modified: 2009-07-15
    
+
    View all other issues in [concept.transform].
    
+
    View all issues with NAD Concepts status.
    
 
    Discussion:
    
 
    
-A few questions on the current WP,
-N2723:
+A recent news group
+article
+points to several defects in the
+specification of reference-related concepts.
 
    
 
    
-30.4.1 [thread.mutex.requirements]/24 says an expression
-mut.unlock() "Throws: Nothing." I'm assuming that, per 17.6.3.11 [res.on.required], errors that violate the precondition "The
-calling thread shall own the mutex" opens the door for throwing an
-exception anyway, such as to report unbalanced unlock operations and
-unlocking from a thread that does not have ownership. Right?
+One problem of the concept RvalueOf as currently defined in
+20.2.1 [concept.transform]:
 
    
+
+
    concept RvalueOf<typename T> {
+ typename type = T&&;
+ requires ExplicitlyConvertible<T&,type> && Convertible<T&&,type>;
+}
+
+template<typename T> concept_map RvalueOf<T&> {
+ typedef T&& type;
+}
+
    
+
 
    
-30.4.1.1 [thread.mutex.class]/3 (actually numbered paragraph "27"
-in the WP; this is just a typo I think) says
+is that if T is an lvalue-reference, the requirement
+Convertible<T&&,type> isn't satisfied for
+lvalue-references, because after reference-collapsing in the concept
+definition we have Convertible<T&,type> in this case,
+which isn't satisfied in the concept map template and also is not the
+right constraint either. I think that the reporter is right that
+SameType requirements should do the job and that we also should
+use the new RvalueReference concept to specify a best matching
+type requirement.
 
    
-
    
+
+
+
    Proposed resolution:
    
 
    
-The behavior of a program is undefined if:
+In 20.2.1 [concept.transform] before p. 4 change as indicated:
 
    
-
      
-
    • it destroys a mutex object owned by any thread,
      • 
-
    • a thread that owns a mutex object calls lock() or try_lock() on that object, or
      • 
-
    • a thread terminates while owning a mutex object.
      • 
-
    
-
    
 
+
    auto concept RvalueOf<typename T> {
+  typenameRvalueReference type = T&&;
+  requires ExplicitlyConvertible<T&, type> && Convertible<T&&, type>SameType<T&, type&>;
+}
+
    
+
+
+
+
+
+
    
+
    1127. rvalue references and iterator traits
    
+
    Section: D.10.1 [iterator.traits] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-05-28  Last modified: 2009-07-15
    
+
    View all other issues in [iterator.traits].
    
+
    View all issues with NAD Concepts status.
    
+
    Discussion:
    
 
    
-As already discussed, I think the second bullet should be removed, and
-such a lock() or try_lock() should fail with an
-exception or returning false, respectively.
+The deprecated support for iterator_traits and legacy (unconstrained)
+iterators features the (exposition only) concept:
 
    
+
+
    concept IsReference<typename T> { } // exposition only
+template<typename T> concept_map IsReference<T&> { }
+
    
 
    
-A potential addition to the list would be
+Now this looks exactly like the LvalueReference concept recently added to
+clause 20, so I wonder if we should use that instead?
+Then I consider the lack of rvalue-reference support, which means that
+move_iterator would always flag as merely supporting the input_iterator_tag
+category.  This suggests we retain the exposition concept, but add a second
+concept_map to support rvalue references.
 
    
-
      
-
    • a thread unlocks a mutex it does not have ownership of.
      • 
-
    
 
    
-but without that the status quo text endorses the technique of the
-program logically transferring ownership of a mutex to another thread
-with correctness enforced by programming discipline. Was that intended?
+I would suggest adding the extra concept_map is the right way forward, but
+still wonder if the two exposition-only concepts in this clause might be
+worth promoting to clause 20.  That question might better be answered with a
+fuller investigation of type_trait/concept unification though.
 
    
 
-
    [
-Summit:
-]
    
 
+
    Proposed resolution:
    
+
    
+In Iterator traits D.10.1 [iterator.traits] para 4 add:
+
    
 
-
    
+
    concept IsReference<typename T> { } // exposition only
+template<typename T> concept_map IsReference<T&> { }
+template<typename T> concept_map IsReference<T&&> { }
+
    
+
+
+
+
+
+
+
    
+
    1128. Missing definition of iterator_traits<T*>
    
+
    Section: 24.3 [iterator.syn] Status: NAD Concepts
+ Submitter: Alisdair Meredith Opened: 2009-05-28  Last modified: 2009-07-16
    
+
    View all issues with NAD Concepts status.
    
+
    Discussion:
    
 
    
-Two resolutions: "not a defect" and "duplicate", as follows:
+The <iterator> header synopsis declares a partial specialization of
+iterator_traits to support pointers, 24.3 [iterator.syn].  The implication
+is that specialization will be described in D10, yet it did not follow the
+rest of the deprecated material into this clause.
 
    
-
      
-
    • 
-30.4.1 [thread.mutex.requirements]/24: NAD. If the precondition
-fails the program has undefined behaviour and therefore an
-implementation may throw an exception already.
-
      • 
+
      
+However, this is not as bad as it first seems!
+There are partial specializations of iterator_traits for types that satisfy
+the various Iterator concepts, and there are concept_maps for pointers to
+explicitly support the RandomAccessIterator concept, so the required
+template will be present - just not in the manner advertised.
+
      
+
      
+I can see two obvious solutions:
+
      
+
+
        
 
      1. 
-30.4.1.1 [thread.mutex.class]/3 bullet 2: Already addressed by issue 893.
+Restore the iterator_traits<T*> partial specialization in D.10
 
        2. 
 
      2. 
-30.4.1.1 [thread.mutex.class]/3 proposed addition: NAD. This is
-already covered by the mutex requirements, which have ownership as a
-Precondition.
+Remove the declaration of iterator_traits<T*> from 24.3 synopsis
 
        3. 
-
    
-
    
+
+
    
+I recommend option (ii) in the wording below
+
    
+
    
+Option (ii) could be extended to strike all the declarations of deprecated
+material from the synopsis, as it is effectively duplicating D.10 anyway.
+This is the approach taken for deprecated library components in the 98/03
+standards.  This is probably a matter best left to the Editor though.
+
    
+
+
+
    Proposed resolution:
    
+
    
+In 24.3 [iterator.syn] strike:
+
    
+
+
    template<class T> struct iterator_traits<T*>;
+
    
+
+
+
+
+
+
+
    
+
    1139. Thread support library not concept enabled
    
+
    Section: 30 [thread] Status: NAD Concepts
+ Submitter: LWG Opened: 2009-06-15  Last modified: 2009-07-15
    
+
    View all other issues in [thread].
    
+
    View all issues with NAD Concepts status.
    
+
    Discussion:
    
+
+
    Addresses US 93, JP 79, UK 333, JP 81
    
+
+
    
+The thread chapter is not concept enabled.
+
    
+
 
 
 
    Proposed resolution:
    
@@ -18137,133 +27968,156 @@ Precondition.
 
 
 
-
 
    
-
    937. Atomics for standard typedef types
    
-
    Section: 29 [atomics] Status: NAD Editorial
- Submitter: Clark Nelson Opened: 2008-12-05  Last modified: 2009-05-23
    
-
    View other active issues in [atomics].
    
-
    View all other issues in [atomics].
    
-
    View all issues with NAD Editorial status.
    
+
    1140. Numerics library not concept enabled
    
+
    Section: 26 [numerics] Status: NAD Concepts
+ Submitter: LWG Opened: 2009-06-15  Last modified: 2009-07-15
    
+
    View all other issues in [numerics].
    
+
    View all issues with NAD Concepts status.
    
 
    Discussion:
    
 
-
    Addresses US 89
    
+
    Addresses US 84
    
 
-
    
 
    
-The types in the table "Atomics for standard typedef types" should be
-typedefs, not classes. These semantics are necessary for compatibility
-with C.
+The numerics chapter is not concept enabled.
 
    
 
 
    
-Change the classes to typedefs.
+The portion of this comment dealing with random numbers was resolved by
+N2836,
+which was accepted in Summit.
 
    
-
    
 
-
    
-N2427
-specified different requirements for atomic analogs of fundamental
-integer types (such as atomic_int) and for atomic analogs of <cstdint>
-typedefs (such as atomic_size_t). Specifically, atomic_int et al. were
-specified to be distinct classes, whereas atomic_size_t et al. were
-specified to be typedefs. Unfortunately, in applying
-N2427
-to the WD, that distinction was erased, and the atomic analog of every <cstdint>
-typedef is required to be a distinct class.
-
    
 
-
    
-It shouldn't be required that the atomic analog of every <cstdint>
-typedef be a typedef for some fundamental integer type. After all,
-<cstdint> is supposed to provide standard names for extended integer
-types. So there was a problem in
-N2427,
-which certainly could have been
-interpreted to require that. But the status quo in the WD is even worse,
-because it's unambiguously wrong.
-
    
 
-
    
-What is needed are words to require the existence of a bunch of type
-names, without specifying whether they are class names or typedef names.
-
    
+
    Proposed resolution:
    
 
-
    [
-Summit:
-]
    
 
 
-
    
-
    
-Change status to NAD, editorial. See US 89 comment notes above.
-
    
+
+
+
    
+
    1141. Input/Output library not concept enabled
    
+
    Section: 27 [input.output] Status: NAD Concepts
+ Submitter: LWG Opened: 2009-06-15  Last modified: 2009-07-15
    
+
    View all other issues in [input.output].
    
+
    View all issues with NAD Concepts status.
    
+
    Discussion:
    
+
+
    Addresses US 85, JP 67, JP 68, JP 69, JP 72, UK 308
    
+
 
    
-Direct the editor to turn the types into typedefs as proposed in the
-comment. Paper approved by committee used typedefs, this appears to have
-been introduced as an editorial change. Rationale: for compatibility
-with C.
+The input/output chapter is not concept enabled.
 
    
-
    
+
 
 
 
    Proposed resolution:
    
+
+
+
+
+
+
    
+
    1142. Regular expressions library not concept enabled
    
+
    Section: 28 [re] Status: NAD Concepts
+ Submitter: LWG Opened: 2009-06-15  Last modified: 2009-07-15
    
+
    View all other issues in [re].
    
+
    View all issues with NAD Concepts status.
    
+
    Discussion:
    
+
+
    Addresses US 86, UK 309, UK 310
    
+
 
    
+The regular expressions chapter is not concept enabled.
 
    
 
 
 
+
    Proposed resolution:
    
+
+
+
 
 
 
    
-
    942. Atomics synopsis typo
    
-
    Section: 29 [atomics] Status: Dup
- Submitter: Holger Grund Opened: 2008-12-19  Last modified: 2009-03-22
    
+
    1143. Atomic operations library not concept enabled
    
+
    Section: 29 [atomics] Status: NAD Concepts
+ Submitter: LWG Opened: 2009-06-15  Last modified: 2009-07-15
    
 
    View other active issues in [atomics].
    
 
    View all other issues in [atomics].
    
-
    View all issues with Dup status.
    
-
    Duplicate of: 880
    
+
    View all issues with NAD Concepts status.
    
 
    Discussion:
    
 
+
    Addresses US 87, UK 311
    
 
+
    
+The atomics chapter is not concept enabled.
+
    
 
 
    
-I'm looking at 29 [atomics] and can't really make sense of a couple of things.
+Needs to also consider issues 923 and 924.
 
    
+
+
+
+
    Proposed resolution:
    
+
+
+
+
+
+
    
+
    1149. Reformulating NonemptyRange axiom
    
+
    Section: 26.5.2.2 [rand.concept.urng] Status: NAD Concepts
+ Submitter: Walter Brown Opened: 2009-06-25  Last modified: 2009-07-15
    
+
    View all issues with NAD Concepts status.
    
+
    Discussion:
    
 
    
-Firstly, there appears to be a typo in the <cstdatomic> synopsis:
+In 26.5.2.2 [rand.concept.urng], we have the following:
 
    
+
    concept UniformRandomNumberGenerator<typename G> : Callable<G> {
+  ...
+  axiom NonemptyRange(G& g) {
+    G::min() < G::max();
+  }
+  ...
+}
+
    
 
-
    
 
    
-The atomic_exchange overload taking an atomic_address
-is missing the second parameter:
+Since the parameter G is in scope throughout the concept, there is no
+need for the axiom to be further parameterized, and so the axiom can be
+slightly simplified as:
 
    
 
-
    void* atomic_exchange(volatile atomic_address*);
+
    axiom NonemptyRange()  {
+  G::min() < G::max();
+}
 
    
 
 
    
-should be
+We can further reformulate so as to avoid any axiom machinery as:
 
    
 
-
    void* atomic_exchange(volatile atomic_address*, void*);
+
    requires True< G::min() < G::max() >;
 
    
 
 
    
-Note, that this is not covered by 880 "Missing atomic exchange parameter",
-which only talks about the atomic_bool.
+This is not only a simpler statement of the same requirement, but also
+forces the requirement to be checked.
 
    
-
    
-
 
 
 
    Proposed resolution:
    
 
    
-Change the synopsis in 29 [atomics]/2:
+In 26.5.2.2 [rand.concept.urng], replace the NonemptyRange axiom by:
 
    
 
-
    void* atomic_exchange(volatile atomic_address*, void*);
+
    axiom NonemptyRange(G& g) { 
+   G::min() < G::max(); 
+}
+requires True< G::min() < G::max() >;
 
    
 
 
@@ -18272,156 +28126,190 @@ Change the synopsis in 29 [atomics]/2:
 
 
 
    
-
    980. mutex lock() missing error conditions
    
-
    Section: 30.4.1 [thread.mutex.requirements] Status: NAD
- Submitter: Ion Gaztañaga Opened: 2009-02-07  Last modified: 2009-03-22
    
-
    View other active issues in [thread.mutex.requirements].
    
-
    View all other issues in [thread.mutex.requirements].
    
+
    1164. promise::swap should pass by rvalue reference
    
+
    Section: 30.6.4 [futures.promise] Status: NAD
+ Submitter: LWG Opened: 2009-06-28  Last modified: 2009-07-17
    
+
    View other active issues in [futures.promise].
    
+
    View all other issues in [futures.promise].
    
 
    View all issues with NAD status.
    
 
    Discussion:
    
-
    
-POSIX 2008 adds two return values for pthread_mutex_xxxlock():
-EOWNERDEAD (owner_dead) and ENOTRECOVERABLE
-(state_not_recoverable). In the first case the mutex is locked,
-in the second case the mutex is not locked.
-
    
-
-
    
-Throwing an exception in the first case can be incompatible with the use
-of Locks, since the Lock::owns_lock() will be false when the lock is
-being destroyed.
-
    
 
-
    
-Consider:
-
    
+
    Addresses UK 341
    
 
-
    //Suppose mutex.lock() throws "owner_dead"
-unique_lock ul(&mutex);
-//mutex left locked if "owner_dead" is thrown
-
    
+
    Description
    
+
    promise::swap accepts its parameter by lvalue reference. This is
+inconsistent with other types that provide a swap member function,
+where those swap functions accept an rvalue reference
    
 
-
    
-Throwing an exception with owner_dead might be also undesirable if
-robust-mutex support is added to C++ and the user has the equivalent of
-pthread_mutex_consistent() to notify the user has fixed the corrupted
-data and the mutex state should be marked consistent.
-
    
+
    Suggestion
    
+
    Change promise::swap to take an rvalue reference.
    
 
-
      
-
    1. 
-For state_not_recoverable add it to the list of Error conditions:
-
      2. 
-
    2. 
-For owner_dead, no proposed resolution.
-
      3. 
-
    
+
    Notes
    
+
    Create an issue. Detlef will look into it. Probably ready as it.
      
 
 
    [
-Summit:
+2009-07 Frankfurt
 ]
    
 
 
 
    
-Not a defect. Handling these error conditions is an implementation
-detail and must be handled below the C++ interface.
+NAD, by virtue of the changed rvalue rules and swap signatures from Summit.
 
    
 
 
 
 
    Proposed resolution:
    
 
+
+
+
+
+
    
+
    1167. pair<T,U> doesn't model LessThanComparable in unconstrained code even if
+      T and U do.
    
+
    Section: 20.3.3 [pairs] Status: NAD Concepts
+ Submitter: Dave Abrahams Opened: 2009-07-01  Last modified: 2009-07-16
    
+
    View other active issues in [pairs].
    
+
    View all other issues in [pairs].
    
+
    View all issues with NAD Concepts status.
    
+
    Discussion:
    
 
    
-Add to 30.4.1 [thread.mutex.requirements], p12:
+LessThanComparable requires (and provides default
+             implementations for) <=,>, and >=.  However, the defaults
+             don't take effect in unconstrained code.
 
    
-
-
    
 
    
--12- Error conditions:
+Still, it's a problem to have types acting one way in
+constrained code and another in unconstrained code, except in cases of
+syntax adaptation.  It's also inconsistent with the containers, which
+supply all those operators.
+
    
+
    
+Totally Unbiased
+Suggested Resolution:
+
    
+
    
+accept the exported concept maps proposal and
+                    change the way this stuff is handled to use an
+                    explicit exported concept map rather than nested
+                    function templates
+
    
+
    
+e.g., remove from the body of std::list
+
    
+
    template <LessThanComparable T, class Allocator> 
+bool operator< (const list<T,Allocator>& x, const list<T,Allocator>& y); 
+template <LessThanComparable T, class Allocator> 
+bool operator> (const list<T,Allocator>& x, const list<T,Allocator>& y); 
+template <LessThanComparable T, class Allocator> 
+bool operator>=(const list<T,Allocator>& x, const list<T,Allocator>& y); 
+template <LessThanComparable T, class Allocator> 
+bool operator<=(const list<T,Allocator>& x, const list<T,Allocator>& y); 
+
    
+
    
+and add this concept_map afterwards:
+
    
+
    template <LessThanComparable T, class Allocator> 
+export concept_map LessThanComparable<list<T,Allocator> >
+{
+    bool operator<(const list<T,Allocator>& x, const list<T,Allocator>& y);
+}
+
    
+
    
+do similarly for std::pair.  While you're at it, do the same for
+operator== and != everywhere, and seek out other such opportunities.
+
    
+
    
+Alternative Resolution: keep the ugly, complex specification and add the
+                       missing operators to std::pair.
 
    
 
-
      
-
    • 
-operation_not_permitted -- if the thread does not have the necessary permission to change 
-the state of the mutex.
-
      • 
-
    • 
-resource_deadlock_would_occur -- if the current thread already owns the mutex and is able 
-to detect it.
-
      • 
-
    • 
-device_or_resource_busy --  if the mutex is already locked and blocking is not possible.
-
      • 
-
    • 
-state_not_recoverable -- if the state protected by the mutex is not recoverable.
-
      • 
-
    
-
    
+
+
    Proposed resolution:
    
 
 
 
 
 
 
    
-
    1022. Response to UK 212
    
-
    Section: 20.8.13.7 [util.dynamic.safety] Status: NAD Editorial
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
    
-
    View all other issues in [util.dynamic.safety].
    
+
    1168. Odd wording for bitset equality operators
    
+
    Section: 20.3.6.2 [bitset.members] Status: NAD Editorial
+ Submitter: Alisdair Meredith Opened: 2009-07-02  Last modified: 2009-07-27
    
+
    View all other issues in [bitset.members].
    
 
    View all issues with NAD Editorial status.
    
 
    Discussion:
    
+
    
+The following wording seems a little unusual to me:
+
    
+
    
+p42/43 20.3.6.2 [bitset.members]
+
    
 
-
    Addresses UK 212
    
+
    
+
    bool operator==(const bitset<N>& rhs) const;
+
    
+
    
+-42- Returns: A nonzero value if the value of each bit in
+*this equals the value of the corresponding bit in
+rhs.
+
    
+
    bool operator!=(const bitset<N>& rhs) const;
+
    
+
    
+-43- Returns: A nonzero value if !(*this == rhs).
+
    
+
    
 
 
    
-The pointer-safety API is nothing to do with smart pointers, so does not
-belong in 20.8.13 [util.smartptr]. In fact it is a set of language
-support features are really belongs in clause 18 [language.support], with the contents declared in a header that
-deals with language-support of memory management.
+"A nonzero value" may be well defined as equivalent to the literal 'true'
+for Booleans, but the wording is clumsy.  I suggest replacing "A nonzero value"
+with the literal 'true' (in appropriate font) in each case.
 
    
 
 
    [
-Summit:
+2009-07-24 Alisdair recommends NAD Editorial.
 ]
    
 
 
-
    Agree in principle, but not with the proposed resolution.
-We believe it
-belongs either a subsection of either 20 [utilities] or 20.8 [memory]
-as part of the general reorganization of 20 [utilities]. The
-declaration should stay in
-<memory>.
-
    
-
-
-
-
    Proposed resolution:
    
+
    [
+2009-07-27 Pete adds:
+]
    
 
 
+
    
+It's obviously editorial. There's no need for further discussion.
+
    
 
+
    [
+2009-07-27 Howard sets to NAD Editorial.
+]
    
 
 
-
    
-
    1025. Response to UK 208
    
-
    Section: 20.7.17 [unord.hash] Status: NAD Future
- Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-03-12
    
-
    View other active issues in [unord.hash].
    
-
    View all other issues in [unord.hash].
    
-
    Discussion:
    
 
-
    Addresses UK 208
    
 
+
    Proposed resolution:
    
 
    
-std::hash should be implemented for much more of the standard
-library. In particular for pair, tuple and all the
-standard containers.
+Change 20.3.6.2 [bitset.members] p42-43:
 
    
 
+
    
+
    bool operator==(const bitset<N>& rhs) const;
+
    
+
    
+-42- Returns: A nonzero value true if the value of each bit in
+*this equals the value of the corresponding bit in
+rhs.
+
    
+
    bool operator!=(const bitset<N>& rhs) const;
+
    
+
    
+-43- Returns: A nonzero value true if !(*this == rhs).
+
    
+
    
 
 
-
    Proposed resolution:
    
-
 
 
 
 
-
+
\ No newline at end of file
diff --git a/libstdc++-v3/doc/html/ext/lwg-defects.html b/libstdc++-v3/doc/html/ext/lwg-defects.html
index 5dedc13..17eb1ec 100644
--- a/libstdc++-v3/doc/html/ext/lwg-defects.html
+++ b/libstdc++-v3/doc/html/ext/lwg-defects.html
@@ -14,11 +14,11 @@ del {background-color:#FFA0A0}
 
-
+
-
+
@@ -29,7 +29,7 @@ del {background-color:#FFA0A0}
 
    
 
    
 Doc. no.N2895=09-0085N2941=09-0131
 
    
 
    
 Date:2009-06-212009-08-02
 
    
 
    
 Project:Howard Hinnant <howard.hinnant@gmail.com>
 
    
 
    
-
    C++ Standard Library Defect Report List (Revision R65)
    
+
    C++ Standard Library Defect Report List (Revision R66)
    
 
   
    Reference ISO/IEC IS 14882:2003(E)
    
   
    Also see:
    
@@ -51,6 +51,58 @@ del {background-color:#FFA0A0}
 
 
    Revision History
    
 
 
    • 
@@ -90,9 +142,9 @@ del {background-color:#FFA0A0}
 
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      • 
+
    • Added the following New issues: 862, 863, 864, 865, 866, 867, 868, 869.
      • 
 
    • Changed the following issues from Pending NAD Editorial to NAD Editorial: 393, 557, 592, 754, 757.
      • 
-
    • Changed the following issues from Pending WP to Open: 644.
      • 
+
    • Changed the following issues from Pending WP to Open: 644.
      • 
 
    • Changed the following issues from WP to Ready: 387, 629.
      • 
 
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  • 708 issues total, up by 12.
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-
    • Added the following New issues: 697, 698, 699, 700, 701, 702, 703, 704, 705, 706, 707, 708.
      • 
+
    • Added the following New issues: 697, 698, 699, 700, 701, 702, 703, 704, 705, 706, 707, 708.
      • 
 
    • Changed the following issues from New to NAD: 583, 584, 662.
      • 
 
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      • 
 
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      • 
 
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      • 
 
    • Changed the following issues from Pending NAD Editorial to NAD Editorial: 553, 571, 591, 633, 636, 641, 642, 648, 649, 656.
      • 
-
    • Changed the following issues from New to Open: 579, 631, 680.
      • 
+
    • Changed the following issues from New to Open: 579, 631, 680.
      • 
 
    • Changed the following issues from Pending WP to Open: 258.
      • 
-
    • Changed the following issues from Ready to Pending WP: 644.
      • 
+
    • Changed the following issues from Ready to Pending WP: 644.
      • 
 
    • Changed the following issues from New to Ready: 577, 660.
      • 
 
    • Changed the following issues from Open to Ready: 488.
      • 
 
    • Changed the following issues from Open to Review: 518.
      • 
@@ -411,7 +463,7 @@ del {background-color:#FFA0A0}
 
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@@ -489,10 +541,10 @@ del {background-color:#FFA0A0}
 
  • Moved issues 520, 521, 530, 535, 537, 538, 540, 541 to WP.
    • 
 
  • Moved issues 504, 512, 516, 544, 549, 554, 555, 558 to NAD.
    • 
 
  • Moved issue 569 to Dup.
    • 
-
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    • 
+
  • Moved issues 518, 523, 524, 542, 556, 557, 559, 597, 606 to Open.
    • 
 
  • Moved issues 543, 545, 549, 549, 598 - 603, 605 to Ready.
    • 
 
  • Moved issues 531, 551, 604 to Review.
    • 
-
  • Added new issues 593, 594, 595, 596, 597, 598, 599, 600, 601, 602, 603, 604, 605, 606, 607, 608, 609.
    • 
+
  • Added new issues 593, 594, 595, 596, 597, 598, 599, 600, 601, 602, 603, 604, 605, 606, 607, 608, 609.
    • 
 
 
 
@@ -505,7 +557,7 @@ del {background-color:#FFA0A0}
 
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  • 587 issues total, up by 13.
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  • 535 issues total.
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@@ -574,7 +626,7 @@ del {background-color:#FFA0A0}
 2005-10-14 post-Mont Tremblant mailing.
 Added new issues 526-528.
 Moved issues 280, 461, 464, 465, 467, 468, 474, 496 from Ready to WP as per the vote from Mont Tremblant.
-Moved issues 247, 294, 342, 362, 369, 371, 376, 384, 475, 478, 495, 497 from Review to Ready.
+Moved issues 247, 294, 342, 362, 369, 371, 376, 384, 475, 478, 495, 497 from Review to Ready.
 Moved issues 498, 504, 506, 509, 510, 511, 512, 513, 514 from New to Open.
 Moved issues 505, 507, 508, 519 from New to Ready.
 Moved issue 500 from New to NAD.
@@ -583,11 +635,11 @@ Moved issue 504-522.
-Added new issues 523-523
+Added new issues 523-523
 
 
  • R37: 
 2005-06 mid-term mailing.
-Added new issues 498-503.
+Added new issues 498-503.
 
    • 
 
  • R36: 
 2005-04 post-Lillehammer mailing. All issues in "ready" status except
@@ -644,7 +696,7 @@ at the meeting.)  Made progress on issues 226 involve wording.
 
    • 
 
  • R23: 
-Pre-Santa Cruz mailing.  Added new issues 367-382.
+Pre-Santa Cruz mailing.  Added new issues 367-382.
 Moved issues in the TC to TC status.
 
    • 
 
  • R22: 
@@ -698,7 +750,7 @@ Changed status of issues
 to Ready.
 
 Closed issues 
-111 277 279 287
+111 277 279 287
 289 293 302 313
 314
 as NAD.
@@ -761,7 +813,7 @@ of issue 83,
 86, 91, 92,
-109. Added issues 190 to
+109. Added issues 190 to
 195. (99-0033/D1209, 14 Oct 99)
 
    • 
 
  • R9: 
@@ -777,10 +829,10 @@ in Dublin. (99-0016/N1193, 21 Apr 99)
 pre-Dublin updated: Added issues 130, 131,
 132, 133, 134,
 135, 136, 137,
-138, 139 (31 Mar 99)
+138, 139 (31 Mar 99)
 
    • 
 
  • R6: 
-pre-Dublin mailing. Added issues 127, 128,
+pre-Dublin mailing. Added issues 127, 128,
 and 129.  (99-0007/N1194, 22 Feb 99)
 
    • 
 
  • R5: 
@@ -790,7 +842,7 @@ for making list public. (30 Dec 98)
 
    • 
 
  • R4: 
 post-Santa Cruz II updated: Issues 110,
-111, 112, 113 added, several
+111, 112, 113 added, several
 issues corrected. (22 Oct 98)
 
    • 
 
  • R3: 
@@ -1383,7 +1435,6 @@ constructor, but there is no matching constructor. 
    
 
    16. Bad ctype_byname<char> decl
    
 
    Section: 22.4.1.4 [locale.codecvt] Status: TC1
  Submitter: Nathan Myers Opened: 1998-08-06  Last modified: 2008-09-26
    
-
    View other active issues in [locale.codecvt].
    
 
    View all other issues in [locale.codecvt].
    
 
    View all issues with TC1 status.
    
 
    Discussion:
    
@@ -1519,7 +1570,6 @@ another get member for bool&, copied from the entry in
 
    19. "Noconv" definition too vague
    
 
    Section: 22.4.1.4 [locale.codecvt] Status: TC1
  Submitter: Nathan Myers Opened: 1998-08-06  Last modified: 2008-09-26
    
-
    View other active issues in [locale.codecvt].
    
 
    View all other issues in [locale.codecvt].
    
 
    View all issues with TC1 status.
    
 
    Duplicate of: 10
    
@@ -1843,7 +1893,6 @@ is assigned to err.
 
    24. "do_convert" doesn't exist
    
 
    Section: 22.4.1.4 [locale.codecvt] Status: TC1
  Submitter: Nathan Myers Opened: 1998-08-06  Last modified: 2008-09-26
    
-
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    Duplicate of: 72
    
@@ -2144,7 +2193,6 @@ the argument value.
    
 
    33. Codecvt<> mentions from_type
    
 
    Section: 22.4.1.4 [locale.codecvt] Status: TC1
  Submitter: Nathan Myers Opened: 1998-08-06  Last modified: 2008-09-26
    
-
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    Duplicate of: 43
    
@@ -2176,6 +2224,7 @@ in the table for the case of _error_ with 
    
 
    34. True/falsename() not in ctype<>
    
 
    Section: 22.4.2.2.2 [facet.num.put.virtuals] Status: TC1
  Submitter: Nathan Myers Opened: 1998-08-06  Last modified: 2008-09-26
    
+
    View other active issues in [facet.num.put.virtuals].
    
 
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    Discussion:
    
@@ -2425,7 +2474,6 @@ setstate(badbit).]
    
 
    42. String ctors specify wrong default allocator
    
 
    Section: 21.4 [basic.string] Status: TC1
  Submitter: Nathan Myers Opened: 1998-08-06  Last modified: 2008-09-26
    
-
    View other active issues in [basic.string].
    
 
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    Discussion:
    
@@ -2514,7 +2562,6 @@ reflects the LWG consensus.
 
    44. Iostreams use operator== on int_type values
    
 
    Section: 27 [input.output] Status: CD1
  Submitter: Nathan Myers Opened: 1998-08-06  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -3127,7 +3174,6 @@ explicitly. 
    
 
    55. Invalid stream position is undefined
    
 
    Section: 27 [input.output] Status: TC1
  Submitter: Matt Austern Opened: 1998-06-26  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -3811,6 +3857,7 @@ item from:
    
 
    69. Must elements of a vector be contiguous?
    
 
    Section: 23.3.6 [vector] Status: TC1
  Submitter: Andrew Koenig Opened: 1998-07-29  Last modified: 2008-09-26
    
+
    View other active issues in [vector].
    
 
    View all other issues in [vector].
    
 
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    Discussion:
    
@@ -3907,7 +3954,6 @@ the declaration of member do_monthname as follows:
    
 
    74. Garbled text for codecvt::do_max_length
    
 
    Section: 22.4.1.4 [locale.codecvt] Status: TC1
  Submitter: Matt Austern Opened: 1998-09-08  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -3936,7 +3982,6 @@ following:
    
 
    Section: 22.4.1.4 [locale.codecvt] Status: TC1
  Submitter:  Matt
 Austern Opened: 1998-09-18  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -3985,7 +4030,6 @@ change the stateT argument type on both member
 
    76. Can a codecvt facet always convert one internal character at a time?
    
 
    Section: 22.4.1.4 [locale.codecvt] Status: CD1
  Submitter: Matt Austern Opened: 1998-09-25  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -4170,7 +4214,6 @@ class complex. This redundancy should be removed.
    
 
    83. String::npos vs. string::max_size()
    
 
    Section: 21.4 [basic.string] Status: TC1
  Submitter: Nico Josuttis Opened: 1998-09-29  Last modified: 2008-09-26
    
-
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    Duplicate of: 89
    
@@ -4204,7 +4247,6 @@ described in this clause...") add a new paragraph:
    
 
    86. String constructors don't describe exceptions
    
 
    Section: 21.4.1 [string.require] Status: TC1
  Submitter: Nico Josuttis Opened: 1998-09-29  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -4348,6 +4390,7 @@ functions do get characters from a streambuf.
    
 
    92. Incomplete Algorithm Requirements
    
 
    Section: 25 [algorithms] Status: CD1
  Submitter: Nico Josuttis Opened: 1998-09-29  Last modified: 2008-09-26
    
+
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    Discussion:
    
@@ -4511,7 +4554,6 @@ for *r++ from T to "convertible to T".
    
 
    103. set::iterator is required to be modifiable, but this allows modification of keys
    
 
    Section: 23.2.4 [associative.reqmts] Status: CD1
  Submitter: AFNOR Opened: 1998-10-07  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -4664,7 +4706,6 @@ Remove the comment which says "// remainder implementation defined" from:
 
    108. Lifetime of exception::what() return unspecified
    
 
    Section: 18.7.1 [type.info] Status: TC1
  Submitter: AFNOR Opened: 1998-10-07  Last modified: 2008-09-26
    
-
    View all other issues in [type.info].
    
 
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    Discussion:
    
 
    In 18.6.1, paragraphs 8-9, the lifetime of the return value of
@@ -5535,7 +5576,6 @@ latter appears to be correct. 
    
 
    127. auto_ptr<> conversion issues
    
 
    Section: D.9.1 [auto.ptr] Status: TC1
  Submitter: Greg Colvin Opened: 1999-02-17  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -5648,7 +5688,6 @@ stream state in case of failure.
    
 
    130. Return type of container::erase(iterator) differs for associative containers
    
 
    Section: 23.2.4 [associative.reqmts], 23.2.3 [sequence.reqmts] Status: CD1
  Submitter: Andrew Koenig Opened: 1999-03-02  Last modified: 2009-05-01
    
-
    View other active issues in [associative.reqmts].
    
 
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    Duplicate of: 451
    
@@ -5940,7 +5979,6 @@ in the standard.
    
 
    139. Optional sequence operation table description unclear
    
 
    Section: 23.2.3 [sequence.reqmts] Status: TC1
  Submitter: Andrew Koenig Opened: 1999-03-30  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -6305,7 +6343,6 @@ that for some iterator j in the range [first2, last2) ...
    
 
    151. Can't currently clear() empty container
    
 
    Section: 23.2.3 [sequence.reqmts] Status: TC1
  Submitter: Ed Brey Opened: 1999-06-21  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -7195,7 +7232,6 @@ separate issue.  (Issue 180. Container member iterator arguments constness has unintended consequences
 
    Section: 21.4 [basic.string] Status: CD1
  Submitter: Dave Abrahams Opened: 1999-07-01  Last modified: 2008-09-26
    
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    Discussion:
    
@@ -8243,7 +8279,7 @@ reformulated yet again to reflect this reality.]
    
 assumes its underlying iterator has persistent pointers and
 references.  Andy Koenig pointed out that it is possible to rewrite
 reverse_iterator so that it no longer makes such an assupmption.
-However, this issue is related to issue 299.  If we
+However, this issue is related to issue 299.  If we
 decide it is intentional that p[n] may return by value
 instead of reference when p is a Random Access Iterator,
 other changes in reverse_iterator will be necessary.]
    
@@ -8435,7 +8471,6 @@ which do not.
 
    202. unique() effects unclear when predicate not an equivalence relation
    
 
    Section: 25.4.9 [alg.unique] Status: CD1
  Submitter: Andrew Koenig Opened: 2000-01-13  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -8910,7 +8945,6 @@ iterators.  Null pointers are singular.
 
    209. basic_string declarations inconsistent
    
 
    Section: 21.4 [basic.string] Status: TC1
  Submitter: Igor Stauder Opened: 2000-02-11  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -8953,6 +8987,7 @@ change.
 
    210. distance first and last confused
    
 
    Section: 25 [algorithms] Status: TC1
  Submitter: Lisa Lippincott Opened: 2000-02-15  Last modified: 2008-09-26
    
+
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    Discussion:
    
@@ -9022,7 +9057,6 @@ is.setstate(ios::failbit) which may throw ios_base::failure
 
    212. Empty range behavior unclear for several algorithms
    
 
    Section: 25.5.7 [alg.min.max] Status: TC1
  Submitter: Nico Josuttis Opened: 2000-02-26  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -9245,7 +9279,6 @@ deliberately, with full knowledge of that limitation.
    
 
    222. Are throw clauses necessary if a throw is already implied by the effects clause?
    
 
    Section: 17.5.1.4 [structure.specifications] Status: TC1
  Submitter: Judy Ward Opened: 2000-03-17  Last modified: 2008-09-26
    
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    Discussion:
    
@@ -9324,7 +9357,6 @@ footnote.
    
 
    224. clear() complexity for associative containers refers to undefined N
    
 
    Section: 23.2.4 [associative.reqmts] Status: TC1
  Submitter: Ed Brey Opened: 2000-03-23  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -9728,7 +9760,6 @@ resolution is the one proposed by Howard.]
    
 
    228. Incorrect specification of "..._byname" facets
    
 
    Section: 22.4 [locale.categories] Status: CD1
  Submitter: Dietmar Kühl Opened: 2000-04-20  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -9863,7 +9894,7 @@ this case only those members are defined to be virtual which are
 defined to be virtual in 'ctype<cT>'.)
    
 
 
    [Post-Tokyo: Dietmar Kühl submitted this issue at the request of
-the LWG to solve the underlying problems raised by issue 138.]
    
+the LWG to solve the underlying problems raised by issue 138.]
    
 
 
 
    [Copenhagen: proposed resolution was revised slightly, to remove
@@ -9879,7 +9910,6 @@ three last virtual functions from messages_byname.]
    
 
    229. Unqualified references of other library entities
    
 
    Section: 17.6.1.1 [contents] Status: CD1
  Submitter: Steve Clamage Opened: 2000-04-19  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -10017,6 +10047,7 @@ Copy Constructible property.
    
 
    231. Precision in iostream?
    
 
    Section: 22.4.2.2.2 [facet.num.put.virtuals] Status: CD1
  Submitter: James Kanze, Stephen Clamage Opened: 2000-04-25  Last modified: 2008-09-26
    
+
    View other active issues in [facet.num.put.virtuals].
    
 
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    Discussion:
    
@@ -10153,7 +10184,6 @@ rationale.]
    
 
    233. Insertion hints in associative containers
    
 
    Section: 23.2.4 [associative.reqmts] Status: CD1
  Submitter: Andrew Koenig Opened: 2000-04-30  Last modified: 2008-09-26
    
-
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    Duplicate of: 192, 246
    
@@ -10303,7 +10333,7 @@ logarithmic in general, but amortized constant if t is inserted right <
 
 
    
 
    234. Typos in allocator definition
    
-
    Section: 20.8.6.1 [allocator.members] Status: CD1
+
    Section: 20.8.4.1 [allocator.members] Status: CD1
  Submitter: Dietmar Kühl Opened: 2000-04-24  Last modified: 2008-09-26
    
 
    View all other issues in [allocator.members].
    
 
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@@ -10412,7 +10442,6 @@ in the standard.
    
 
    239. Complexity of unique() and/or unique_copy incorrect
    
 
    Section: 25.4.9 [alg.unique] Status: CD1
  Submitter: Angelika Langer Opened: 2000-05-15  Last modified: 2008-09-26
    
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    Discussion:
    
@@ -10518,7 +10547,6 @@ bound.  The LWG preferred an exact count.]
    
 
    241. Does unique_copy() require CopyConstructible and Assignable?
    
 
    Section: 25.4.9 [alg.unique] Status: CD1
  Submitter: Angelika Langer Opened: 2000-05-15  Last modified: 2008-09-26
    
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    Discussion:
    
@@ -11089,7 +11117,6 @@ issue is stylistic rather than a matter of correctness.
    
 
    253. valarray helper functions are almost entirely useless
    
 
    Section: 26.6.2.1 [valarray.cons], 26.6.2.2 [valarray.assign] Status: CD1
  Submitter: Robert Klarer Opened: 2000-07-31  Last modified: 2008-09-26
    
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    Discussion:
    
@@ -11962,7 +11989,6 @@ to:
 
    263. Severe restriction on basic_string reference counting
    
 
    Section: 21.4 [basic.string] Status: CD1
  Submitter: Kevlin Henney Opened: 2000-09-04  Last modified: 2008-09-26
    
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    Discussion:
    
@@ -12044,7 +12070,6 @@ Change the following sentence in 21.3 paragraph 5 from
 
    264. Associative container insert(i, j) complexity requirements are not feasible.
    
 
    Section: 23.2.4 [associative.reqmts] Status: CD1
  Submitter: John Potter Opened: 2000-09-07  Last modified: 2008-09-26
    
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    Duplicate of: 102
    
@@ -12541,7 +12566,6 @@ Add parentheses like so: rdstate()==(state|ios_base::badbit).
 
    273. Missing ios_base qualification on members of a dependent class
    
 
    Section: 27 [input.output] Status: CD1
  Submitter: Martin Sebor Opened: 2000-11-02  Last modified: 2008-09-26
    
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    Discussion:
    
@@ -12999,7 +13023,6 @@ this solution is safe and correct.
 
    281. std::min() and max() requirements overly restrictive
    
 
    Section: 25.5.7 [alg.min.max] Status: CD1
  Submitter: Martin Sebor Opened: 2000-12-02  Last modified: 2008-09-26
    
-
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    Duplicate of: 486
    
@@ -13031,6 +13054,7 @@ is unnecessary.
 
    282. What types does numpunct grouping refer to?
    
 
    Section: 22.4.2.2.2 [facet.num.put.virtuals] Status: CD1
  Submitter: Howard Hinnant Opened: 2000-12-05  Last modified: 2008-09-26
    
+
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    Discussion:
    
@@ -13089,7 +13113,6 @@ Howard, Bill, Pete, Benjamin, Nathan, Dietmar, Boris, and Martin.]
    
 
    283. std::replace() requirement incorrect/insufficient
    
 
    Section: 25.4.5 [alg.replace] Status: CD1
  Submitter: Martin Sebor Opened: 2000-12-15  Last modified: 2008-09-26
    
-
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    Duplicate of: 483
    
@@ -13842,7 +13865,6 @@ list" is excessively vague.]
    
 
    301. basic_string template ctor effects clause omits allocator argument
    
 
    Section: 21.4.1 [string.require] Status: CD1
  Submitter: Martin Sebor Opened: 2001-01-27  Last modified: 2008-09-26
    
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    Discussion:
    
@@ -14438,7 +14460,6 @@ and it was deliberately not adopted.  Nevertheless, the LWG believes
 
    308. Table 82 mentions unrelated headers
    
 
    Section: 27 [input.output] Status: CD1
  Submitter: Martin Sebor Opened: 2001-03-15  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -14663,7 +14684,6 @@ Change the "range" from (last - first) to [first, last).
 
    316. Vague text in Table 69
    
 
    Section: 23.2.4 [associative.reqmts] Status: CD1
  Submitter: Martin Sebor Opened: 2001-05-04  Last modified: 2008-09-26
    
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    Discussion:
    
@@ -14696,7 +14716,6 @@ takes place...
 
    317. Instantiation vs. specialization of facets
    
 
    Section: 22 [localization] Status: CD1
  Submitter: Martin Sebor Opened: 2001-05-04  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -15686,7 +15705,6 @@ library (though a deprecated one).
    
 
    337. replace_copy_if's template parameter should be InputIterator
    
 
    Section: 25.4.5 [alg.replace] Status: CD1
  Submitter: Detlef Vollmann Opened: 2001-09-07  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -15711,7 +15729,6 @@ parameter name conveys real normative meaning.
 
    338.  is whitespace allowed between `-' and a digit?
    
 
    Section: 22.4 [locale.categories] Status: CD1
  Submitter: Martin Sebor Opened: 2001-09-17  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -16270,7 +16287,6 @@ be considered NAD.
    
 
    354. Associative container lower/upper bound requirements
    
 
    Section: 23.2.4 [associative.reqmts] Status: CD1
  Submitter: Hans Aberg Opened: 2001-12-17  Last modified: 2008-09-26
    
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    Discussion:
    
@@ -16337,7 +16353,6 @@ key greater than k, or a.end() if such an element is not found.
 
    355. Operational semantics for a.back()
    
 
    Section: 23.2.3 [sequence.reqmts] Status: CD1
  Submitter: Yaroslav Mironov Opened: 2002-01-23  Last modified: 2008-09-26
    
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    Discussion:
    
@@ -16764,7 +16779,6 @@ for each class derived from basic_streambuf in this clause
 
    365. Lack of const-qualification in clause 27
    
 
    Section: 27 [input.output] Status: CD1
  Submitter: Walter Brown, Marc Paterno Opened: 2002-05-10  Last modified: 2008-09-26
    
-
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    Discussion:
    
@@ -17349,8 +17363,8 @@ with that discussion.
 I have checked this newsgroup, as well as attempted a search of the
 Active/Defect/Closed Issues List on the site for the words "s is
 derefer" so I believe this has not been proposed before.  Furthermore,
-the "Lists by Index" mentions only DR 299 on section
-24.1.4, and DR 299 is not related to this issue.
+the "Lists by Index" mentions only DR 299 on section
+24.1.4, and DR 299 is not related to this issue.
 
    
 
 
    
@@ -17490,7 +17504,7 @@ which is the same as iterator_traits<Iterator>::reference.
   to Iterator's value type.  The return type specified for
   reverse_iterator's operator[] would thus appear to be impossible.
    
 
-
    With the resolution of issue 299, the type of
+
    With the resolution of issue 299, the type of
   a[n] will continue to be required (for random access
   iterators) to be convertible to the value type, and also a[n] =
   t will be a valid expression.  Implementations of
@@ -17979,13 +17993,13 @@ The proposed wording neglects the 3 newer to_string overloads.
 
 
    
 
    400. redundant type cast in lib.allocator.members
    
-
    Section: 20.8.6.1 [allocator.members] Status: CD1
+
    Section: 20.8.4.1 [allocator.members] Status: CD1
  Submitter: Markus Mauhart Opened: 2003-02-27  Last modified: 2008-09-26
    
 
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    Discussion:
    
 
    
-20.8.6.1 [allocator.members] allocator members, contains
+20.8.4.1 [allocator.members] allocator members, contains
 the following 3 lines:
 
    
 
@@ -18097,7 +18111,7 @@ issue to Ready status to be voted into the WP at Kona.
 
 
    
 
    402. wrong new expression in [some_]allocator::construct
    
-
    Section: X [allocator.requirements], 20.8.6.1 [allocator.members] Status: CD1
+
    Section: X [allocator.requirements], 20.8.4.1 [allocator.members] Status: CD1
  Submitter: Markus Mauhart Opened: 2003-02-27  Last modified: 2008-09-26
    
 
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@@ -18105,13 +18119,13 @@ issue to Ready status to be voted into the WP at Kona.
 
    Discussion:
    
 
    
 This applies to the new expression that is contained in both par12 of
-20.8.6.1 [allocator.members] and in par2 (table 32) of  [default.con.req].
+20.8.4.1 [allocator.members] and in par2 (table 32) of  [default.con.req].
 I think this new expression is wrong, involving unintended side
 effects.
 
    
 
 
-
    20.8.6.1 [allocator.members]  contains the following 3 lines:
    
+
    20.8.4.1 [allocator.members]  contains the following 3 lines:
    
 
 
      11 Returns: the largest value N for which the call allocate(N,0) might succeed.
      void construct(pointer p, const_reference val);
@@ -18968,7 +18982,7 @@ use the right wording.]
    
 
 
    
 
    425. return value of std::get_temporary_buffer
    
-
    Section: 20.8.9 [temporary.buffer] Status: CD1
+
    Section: 20.8.7 [temporary.buffer] Status: CD1
  Submitter: Martin Sebor Opened: 2003-09-18  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -19553,7 +19567,6 @@ text.]
    
 
    438. Ambiguity in the "do the right thing" clause
    
 
    Section: 23.2.3 [sequence.reqmts] Status: CD1
  Submitter: Howard Hinnant Opened: 2003-10-20  Last modified: 2009-05-01
    
-
    View other active issues in [sequence.reqmts].
    
 
    View all other issues in [sequence.reqmts].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -19917,7 +19930,6 @@ In section 27.5.3.1 [fpos.members], change the declaration of
 
    442. sentry::operator bool() inconsistent signature
    
 
    Section: 27.7.2.4 [ostream::sentry] Status: CD1
  Submitter: Vincent Leloup Opened: 2003-11-18  Last modified: 2008-09-26
    
-
    View other active issues in [ostream::sentry].
    
 
    View all other issues in [ostream::sentry].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -20659,6 +20671,7 @@ An implementation may also accept additional implementation-defined formats.
 
    464. Suggestion for new member functions in standard containers
    
 
    Section: 23.3.6 [vector], 23.4.1 [map] Status: CD1
  Submitter: Thorsten Ottosen Opened: 2004-05-12  Last modified: 2008-09-26
    
+
    View other active issues in [vector].
    
 
    View all other issues in [vector].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -20910,6 +20923,7 @@ the value need not be valid.
 
    469. vector<bool> ill-formed relational operators
    
 
    Section: 23.3.6 [vector] Status: CD1
  Submitter: Martin Sebor Opened: 2004-06-28  Last modified: 2009-05-01
    
+
    View other active issues in [vector].
    
 
    View all other issues in [vector].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -20961,7 +20975,6 @@ I propose to strike the Footnote.
 
    475. May the function object passed to for_each modify the elements of the iterated sequence?
    
 
    Section: 25.3.4 [alg.foreach] Status: CD1
  Submitter: Stephan T. Lavavej, Jaakko Jarvi Opened: 2004-07-09  Last modified: 2008-09-26
    
-
    View other active issues in [alg.foreach].
    
 
    View all other issues in [alg.foreach].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -21202,7 +21215,6 @@ Toronto: moved to Ready.
 
    495. Clause 22 template parameter requirements
    
 
    Section: 22 [localization] Status: CD1
  Submitter: Beman Dawes Opened: 2005-01-10  Last modified: 2008-09-26
    
-
    View other active issues in [localization].
    
 
    View all other issues in [localization].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -21279,6 +21291,7 @@ requirements of charT (described in 21 [strings]).
 
    496. Illegal use of "T" in vector<bool>
    
 
    Section: 23.3.6 [vector] Status: CD1
  Submitter: richard@ex-parrot.com Opened: 2005-02-10  Last modified: 2008-09-26
    
+
    View other active issues in [vector].
    
 
    View all other issues in [vector].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -21407,7 +21420,6 @@ Berlin:  Voted to WP.  N1932 adopts the proposed resolution:  see Table 5 row 1.
 
    507. Missing requirement for variate_generator::operator()
    
 
    Section: 26.5 [rand], TR1 5.1.3 [tr.rand.var] Status: CD1
  Submitter: Walter Brown Opened: 2005-07-03  Last modified: 2008-09-26
    
-
    View other active issues in [rand].
    
 
    View all other issues in [rand].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -21854,7 +21866,6 @@ template <class... Types>
 
    524. regex named character classes and case-insensitivity don't mix
    
 
    Section: 28 [re] Status: CD1
  Submitter: Eric Niebler Opened: 2005-07-01  Last modified: 2008-09-26
    
-
    View other active issues in [re].
    
 
    View all other issues in [re].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -22025,7 +22036,6 @@ in the BoundArgs... pack expansion throws an exception.
 
    530. Must elements of a string be contiguous?
    
 
    Section: 21.4 [basic.string] Status: CD1
  Submitter: Matt Austern Opened: 2005-11-15  Last modified: 2008-09-26
    
-
    View other active issues in [basic.string].
    
 
    View all other issues in [basic.string].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -22153,7 +22163,7 @@ writing to out of bounds memory when n == 0.  Martin provided fix.
 
 
    
 
    533. typo in 2.2.3.10/1
    
-
    Section: 20.8.13.2.11 [util.smartptr.getdeleter], TR1 2.2.3.10 [tr.util.smartptr.getdeleter] Status: CD1
+
    Section: 20.8.10.2.11 [util.smartptr.getdeleter], TR1 2.2.3.10 [tr.util.smartptr.getdeleter] Status: CD1
  Submitter: Paolo Carlini Opened: 2005-11-09  Last modified: 2009-05-01
    
 
    View all other issues in [util.smartptr.getdeleter].
    
 
    View all issues with CD1 status.
    
@@ -22186,7 +22196,6 @@ If *this p owns a deleter d...
 
    534. Missing basic_string members
    
 
    Section: 21.4 [basic.string] Status: CD1
  Submitter: Alisdair Meredith Opened: 2005-11-16  Last modified: 2008-09-26
    
-
    View other active issues in [basic.string].
    
 
    View all other issues in [basic.string].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -22422,7 +22431,6 @@ After 27.6.2.4p3 change:
 
    538. 241 again: Does unique_copy() require CopyConstructible and Assignable?
    
 
    Section: 25.4.9 [alg.unique] Status: CD1
  Submitter: Howard Hinnant Opened: 2006-02-09  Last modified: 2008-09-26
    
-
    View other active issues in [alg.unique].
    
 
    View all other issues in [alg.unique].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -22479,7 +22487,7 @@ Otherwise CopyConstructible is not required.
 
 
    
 
    540. shared_ptr<void>::operator*()
    
-
    Section: 20.8.13.2.5 [util.smartptr.shared.obs], TR1 2.2.3.5 [tr.util.smartptr.shared.obs] Status: CD1
+
    Section: 20.8.10.2.5 [util.smartptr.shared.obs], TR1 2.2.3.5 [tr.util.smartptr.shared.obs] Status: CD1
  Submitter: Martin Sebor Opened: 2005-10-15  Last modified: 2008-09-26
    
 
    View all other issues in [util.smartptr.shared.obs].
    
 
    View all issues with CD1 status.
    
@@ -22537,7 +22545,7 @@ definition) of the function shall be well-formed.
 
 
    
 
    541. shared_ptr template assignment and void
    
-
    Section: 20.8.13.2 [util.smartptr.shared], TR1 2.2.3 [tr.util.smartptr.shared] Status: CD1
+
    Section: 20.8.10.2 [util.smartptr.shared], TR1 2.2.3 [tr.util.smartptr.shared] Status: CD1
  Submitter: Martin Sebor Opened: 2005-10-16  Last modified: 2008-09-26
    
 
    View other active issues in [util.smartptr.shared].
    
 
    View all other issues in [util.smartptr.shared].
    
@@ -22618,7 +22626,7 @@ public:
 
 
    
 
    542. shared_ptr observers
    
-
    Section: 20.8.13.2.5 [util.smartptr.shared.obs], TR1 2.2.3.5 [tr.util.smartptr.shared.obs] Status: CD1
+
    Section: 20.8.10.2.5 [util.smartptr.shared.obs], TR1 2.2.3.5 [tr.util.smartptr.shared.obs] Status: CD1
  Submitter: Martin Sebor Opened: 2005-10-18  Last modified: 2008-09-26
    
 
    View all other issues in [util.smartptr.shared.obs].
    
 
    View all issues with CD1 status.
    
@@ -22658,7 +22666,7 @@ capture the intent.
 
 
    Proposed resolution:
    
 
    
-Change 20.8.13.2.5 [util.smartptr.shared.obs] p12:
+Change 20.8.10.2.5 [util.smartptr.shared.obs] p12:
 
    
 
    
 [Note: use_count() is not necessarily efficient. Use only for
@@ -22666,7 +22674,7 @@ debugging and testing purposes, not for production code. --end note
 
    
 
 
    
-Change 20.8.13.3.5 [util.smartptr.weak.obs] p3:
+Change 20.8.10.3.5 [util.smartptr.weak.obs] p3:
 
    
 
    
 [Note: use_count() is not necessarily efficient. Use only for
@@ -22755,7 +22763,7 @@ lengths, and strides, as explained in the previous section.
 
 
    
 
    545. When is a deleter deleted?
    
-
    Section: 20.8.13.2.11 [util.smartptr.getdeleter], TR1 2.2.3.2 [tr.util.smartptr.shared.dest] Status: CD1
+
    Section: 20.8.10.2.11 [util.smartptr.getdeleter], TR1 2.2.3.2 [tr.util.smartptr.shared.dest] Status: CD1
  Submitter: Matt Austern Opened: 2006-01-10  Last modified: 2008-09-26
    
 
    View all other issues in [util.smartptr.getdeleter].
    
 
    View all issues with CD1 status.
    
@@ -22773,7 +22781,7 @@ instances). We should say which it is.
 
 
    Proposed resolution:
    
 
    
-Add after the first sentence of 20.8.13.2.11 [util.smartptr.getdeleter]/1:
+Add after the first sentence of 20.8.10.2.11 [util.smartptr.getdeleter]/1:
 
    
 
    
 
    
@@ -23619,7 +23627,7 @@ Disposition: Review
 
 
    
 
    575. the specification of ~shared_ptr is MT-unfriendly, makes implementation assumptions
    
-
    Section: 20.8.13.2.2 [util.smartptr.shared.dest], TR1 2.2.3.2 [tr.util.smartptr.shared.dest] Status: CD1
+
    Section: 20.8.10.2.2 [util.smartptr.shared.dest], TR1 2.2.3.2 [tr.util.smartptr.shared.dest] Status: CD1
  Submitter: Peter Dimov Opened: 2006-04-23  Last modified: 2008-09-26
    
 
    View all other issues in [util.smartptr.shared.dest].
    
 
    View all issues with CD1 status.
    
@@ -23801,7 +23809,7 @@ conditions hold: !(value < *j) or comp(value, *j)
 
 
    
 
    578. purpose of hint to allocator::allocate()
    
-
    Section: 20.8.6.1 [allocator.members] Status: CD1
+
    Section: 20.8.4.1 [allocator.members] Status: CD1
  Submitter: Martin Sebor Opened: 2006-05-17  Last modified: 2008-09-26
    
 
    View all other issues in [allocator.members].
    
 
    View all issues with CD1 status.
    
@@ -24403,7 +24411,6 @@ Kona (2007) Added proposed wording and moved to Review.
 
    598. Decimal: Conversion to integral should truncate, not round.
    
 
    Section: TRDecimal 3.2 [trdec.types.types] Status: TRDec
  Submitter: Daniel Krugler Opened: 2006-05-28  Last modified: 2007-04-21
    
-
    View other active issues in [trdec.types.types].
    
 
    View all other issues in [trdec.types.types].
    
 
    View all issues with TRDec status.
    
 
    Discussion:
    
@@ -25497,7 +25504,6 @@ undefined behavior if replacing the setjmp and longjmp by
 
    620. valid uses of empty valarrays
    
 
    Section: 26.6.2.1 [valarray.cons] Status: CD1
  Submitter: Martin Sebor Opened: 2007-01-20  Last modified: 2008-09-26
    
-
    View other active issues in [valarray.cons].
    
 
    View all other issues in [valarray.cons].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -25747,7 +25753,7 @@ errors.
         
    
 
 
    [
-See 397 and 418 for related issues.
+See 397 and 418 for related issues.
 ]
    
 
 
@@ -25988,13 +25994,13 @@ These operators allow the results of a generalized subscripting operation to be
 
 
    
 
    628. Inconsistent definition of basic_regex constructor
    
-
    Section: 28.9 [re.regex] Status: CD1
+
    Section: 28.8 [re.regex] Status: CD1
  Submitter: Bo Persson Opened: 2007-01-23  Last modified: 2008-09-26
    
 
    View all other issues in [re.regex].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-Section 28.9 [re.regex] lists a constructor
+Section 28.8 [re.regex] lists a constructor
 
    
 
 
    template<class InputIterator>
@@ -26003,14 +26009,14 @@ basic_regex(InputIterator first, InputIterator last,
 
    
 
 
    
-However, in section 28.9.2 [re.regex.construct], this constructor takes a 
+However, in section 28.8.2 [re.regex.construct], this constructor takes a 
 pair of ForwardIterator.
 
    
 
 
 
    Proposed resolution:
    
 
    
-Change 28.9.2 [re.regex.construct]:
+Change 28.8.2 [re.regex.construct]:
 
    
 
 
    template <class ForwardIterator InputIterator>
@@ -26119,7 +26125,7 @@ will extract unambiguously.]
 
 
    
 
    634. allocator.address() doesn't work for types overloading operator&
    
-
    Section: 20.8.6.1 [allocator.members] Status: CD1
+
    Section: 20.8.4.1 [allocator.members] Status: CD1
  Submitter: Howard Hinnant Opened: 2007-02-07  Last modified: 2008-09-26
    
 
    View all other issues in [allocator.members].
    
 
    View all issues with CD1 status.
    
@@ -26127,7 +26133,7 @@ will extract unambiguously.]
 
    Discussion:
    
 
 
    
-20.8.6.1 [allocator.members] says:
+20.8.4.1 [allocator.members] says:
 
    
 
    
 
    pointer address(reference x) const;
    
@@ -26139,7 +26145,7 @@ will extract unambiguously.]
 
    
 
 
    
-20.8.6.1 [allocator.members] defines CopyConstructible which currently not
+20.8.4.1 [allocator.members] defines CopyConstructible which currently not
 only defines the semantics of copy construction, but also restricts what an overloaded
 operator& may do.  I believe proposals are in the works (such as concepts
 and rvalue reference) to decouple these two requirements.  Indeed it is not evident
@@ -26170,7 +26176,7 @@ is expected to make use of allocator::address mandatory for containers.
 
 
    Proposed resolution:
    
 
    
-Change 20.8.6.1 [allocator.members]:
+Change 20.8.4.1 [allocator.members]:
 
    
 
 
    
@@ -26423,21 +26429,21 @@ A local variable punct is initialized via
 
 
    
 
    646. const incorrect match_result members
    
-
    Section: 28.11.4 [re.results.form] Status: CD1
+
    Section: 28.10.4 [re.results.form] Status: CD1
  Submitter: Daniel Krügler Opened: 2007-02-26  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-28.11.4 [re.results.form] (root and para 3) in N2134 defines the two function template
+28.10.4 [re.results.form] (root and para 3) in N2134 defines the two function template
 members format as non-const functions, although they are declared
-as const in 28.11 [re.results]/3.
+as const in 28.10 [re.results]/3.
 
    
 
 
 
    Proposed resolution:
    
 
    
 Add the missing const specifier to both format overloads described
-in section 28.11.4 [re.results.form].
+in section 28.10.4 [re.results.form].
 
    
 
 
@@ -26446,24 +26452,24 @@ in section 28.11.4 [re.results.form].
 
 
    
 
    650. regex_token_iterator and const correctness
    
-
    Section: 28.13.2 [re.tokiter] Status: CD1
+
    Section: 28.12.2 [re.tokiter] Status: CD1
  Submitter: Daniel Krügler Opened: 2007-03-05  Last modified: 2008-09-26
    
 
    View all other issues in [re.tokiter].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-Both the class definition of regex_token_iterator (28.13.2
-[re.tokiter]/6) and the latter member specifications (28.13.2.2
+Both the class definition of regex_token_iterator (28.12.2
+[re.tokiter]/6) and the latter member specifications (28.12.2.2
 [re.tokiter.comp]/1+2) declare both comparison operators as
 non-const functions. Furtheron, both dereference operators are
-unexpectedly also declared as non-const in 28.13.2 [re.tokiter]/6
-as well as in (28.13.2.3 [re.tokiter.deref]/1+2).
+unexpectedly also declared as non-const in 28.12.2 [re.tokiter]/6
+as well as in (28.12.2.3 [re.tokiter.deref]/1+2).
 
    
 
 
 
    Proposed resolution:
    
 
    
-1) In (28.13.2 [re.tokiter]/6) change the current declarations
+1) In (28.12.2 [re.tokiter]/6) change the current declarations
 
    
 
 
    bool operator==(const regex_token_iterator&) const;
@@ -26473,7 +26479,7 @@ const value_type* operator->() const;
 
    
 
 
    
-2) In 28.13.2.2 [re.tokiter.comp] change the following declarations
+2) In 28.12.2.2 [re.tokiter.comp] change the following declarations
 
    
 
 
    bool operator==(const regex_token_iterator& right) const;
@@ -26481,7 +26487,7 @@ bool operator!=(const regex_token_iterator& right) const;
 
    
 
 
    
-3) In 28.13.2.3 [re.tokiter.deref] change the following declarations
+3) In 28.12.2.3 [re.tokiter.deref] change the following declarations
 
    
 
 
    const value_type& operator*() const;
@@ -26501,17 +26507,17 @@ The LWG voted to accelerate this issue to Ready status to be voted into the WP a
 
 
    
 
    651. Missing preconditions for regex_token_iterator c'tors
    
-
    Section: 28.13.2.1 [re.tokiter.cnstr] Status: CD1
+
    Section: 28.12.2.1 [re.tokiter.cnstr] Status: CD1
  Submitter: Daniel Krügler Opened: 2007-03-05  Last modified: 2008-09-26
    
 
    View all other issues in [re.tokiter.cnstr].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-The text provided in 28.13.2.1 [re.tokiter.cnstr]/2+3 describes
+The text provided in 28.12.2.1 [re.tokiter.cnstr]/2+3 describes
 the effects of the three non-default constructors of class
 template regex_token_iterator but is does not clarify which values
 are legal values for submatch/submatches. This becomes
-an issue, if one takes 28.13.2 [re.tokiter]/9 into account, which explains
+an issue, if one takes 28.12.2 [re.tokiter]/9 into account, which explains
 the notion of a "current match" by saying:
 
    
 
@@ -26530,7 +26536,7 @@ are legal arguments or not - it seems they are not.
 
    Proposed resolution:
    
 
    
 Add the following precondition paragraph just before the current
-28.13.2.1 [re.tokiter.cnstr]/2:
+28.12.2.1 [re.tokiter.cnstr]/2:
 
    
 
 
    
@@ -26550,22 +26556,22 @@ The LWG voted to accelerate this issue to Ready status to be voted into the WP a
 
 
    
 
    652. regex_iterator and const correctness
    
-
    Section: 28.13.1 [re.regiter] Status: CD1
+
    Section: 28.12.1 [re.regiter] Status: CD1
  Submitter: Daniel Krügler Opened: 2007-03-05  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
-
    Both the class definition of regex_iterator (28.13.1 [re.regiter]/1)
-and the latter member specification (28.13.1.2 [re.regiter.comp]/1+2)
+
    Both the class definition of regex_iterator (28.12.1 [re.regiter]/1)
+and the latter member specification (28.12.1.2 [re.regiter.comp]/1+2)
 declare both comparison operators as
 non-const functions. Furtheron, both dereference operators are
-unexpectedly also declared as non-const in 28.13.1 [re.regiter]/1
-as well as in (28.13.1.3 [re.regiter.deref]/1+2).
+unexpectedly also declared as non-const in 28.12.1 [re.regiter]/1
+as well as in (28.12.1.3 [re.regiter.deref]/1+2).
 
    
 
 
 
    Proposed resolution:
    
 
    
-1) In (28.13.1 [re.regiter]/1) change the current declarations
+1) In (28.12.1 [re.regiter]/1) change the current declarations
 
    
 
 
    bool operator==(const regex_iterator&) const;
@@ -26575,7 +26581,7 @@ const value_type* operator->() const;
 
    
 
 
    
-2) In 28.13.1.3 [re.regiter.deref] change the following declarations
+2) In 28.12.1.3 [re.regiter.deref] change the following declarations
 
    
 
 
    const value_type& operator*() const;
@@ -26583,7 +26589,7 @@ const value_type* operator->() const;
 
    
 
 
    
-3) In 28.13.1.2 [re.regiter.comp] change the following declarations
+3) In 28.12.1.2 [re.regiter.comp] change the following declarations
 
    
 
 
    bool operator==(const regex_iterator& right) const;
@@ -27084,6 +27090,7 @@ four characters long, usually three letters and a space.
 
    672. Swappable requirements need updating
    
 
    Section: X [utility.arg.requirements] Status: CD1
  Submitter: Howard Hinnant Opened: 2007-05-04  Last modified: 2008-09-26
    
+
    View other active issues in [utility.arg.requirements].
    
 
    View all other issues in [utility.arg.requirements].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -27226,7 +27233,7 @@ Kona (2007): We like the change to the Swappable requirements to use
 move semantics. The issue relating to the support of proxies is
 separable from the one relating to move semantics, and it's bigger than
 just swap. We'd like to address only the move semantics changes under
-this issue, and open a separated issue (742) to handle proxies. Also, there
+this issue, and open a separated issue (742) to handle proxies. Also, there
 may be a third issue, in that the current definition of Swappable does
 not permit rvalues to be operands to a swap operation, and Howard's
 proposed resolution would allow the right-most operand to be an rvalue,
@@ -27241,7 +27248,7 @@ swap to be rvalues).
 
 
    
 
    673. unique_ptr update
    
-
    Section: 20.8.12 [unique.ptr] Status: CD1
+
    Section: 20.8.9 [unique.ptr] Status: CD1
  Submitter: Howard Hinnant Opened: 2007-05-04  Last modified: 2008-09-26
    
 
    View all other issues in [unique.ptr].
    
 
    View all issues with CD1 status.
    
@@ -27363,7 +27370,7 @@ the proposed resolutions below.
 
  • 
 
 
    
-Change 20.8.12.2 [unique.ptr.single]:
+Change 20.8.9.2 [unique.ptr.single]:
 
    
 
 
    template <class T, class D = default_delete<T>> class unique_ptr {
@@ -27374,7 +27381,7 @@ Change 20.8.12.2 [unique.ptr.single]:
 
    
 
 
    
-Change 20.8.12.2.4 [unique.ptr.single.observers]:
+Change 20.8.9.2.4 [unique.ptr.single.observers]:
 
    
 
 
    T& typename add_lvalue_reference<T>::type operator*() const;
@@ -27384,7 +27391,7 @@ Change 20.8.12.2.4 [unique.ptr.single.observers]:
 
 
  • 
 
    
-Change 20.8.12.2 [unique.ptr.single]:
+Change 20.8.9.2 [unique.ptr.single]:
 
    
 
 
    template <class T, class D = default_delete<T>> class unique_ptr {
@@ -27416,7 +27423,7 @@ and CopyAssignable.
 
    
 
 
    
-Change 20.8.12.2.1 [unique.ptr.single.ctor]:
+Change 20.8.9.2.1 [unique.ptr.single.ctor]:
 
    
 
 
    unique_ptr(T* pointer p);
@@ -27456,7 +27463,7 @@ internally stored deleter which was constructed from
 
    
 
 
    
-Change 20.8.12.2.3 [unique.ptr.single.asgn]:
+Change 20.8.9.2.3 [unique.ptr.single.asgn]:
 
    
 
 
    
@@ -27469,7 +27476,7 @@ convertible to T* pointer.
 
    
 
 
    
-Change 20.8.12.2.4 [unique.ptr.single.observers]:
+Change 20.8.9.2.4 [unique.ptr.single.observers]:
 
    
 
 
    
@@ -27479,7 +27486,7 @@ Change 20.8.12.2.4 [unique.ptr.single.observers]:
 
    
 
 
    
-Change 20.8.12.2.5 [unique.ptr.single.modifiers]:
+Change 20.8.9.2.5 [unique.ptr.single.modifiers]:
 
    
 
 
    
@@ -27489,7 +27496,7 @@ Change 20.8.12.2.5 [unique.ptr.single.modifiers]:
 
    
 
 
    
-Change 20.8.12.3 [unique.ptr.runtime]:
+Change 20.8.9.3 [unique.ptr.runtime]:
 
    
 
 
    template <class T, class D> class unique_ptr<T[], D> {
@@ -27509,7 +27516,7 @@ public:
 
    
 
 
    
-Change 20.8.12.3.1 [unique.ptr.runtime.ctor]:
+Change 20.8.9.3.1 [unique.ptr.runtime.ctor]:
 
    
 
 
    
@@ -27528,7 +27535,7 @@ these members. -- end note]
 
    
 
 
    
-Change 20.8.12.3.3 [unique.ptr.runtime.modifiers]:
+Change 20.8.9.3.3 [unique.ptr.runtime.modifiers]:
 
    
 
 
    
@@ -27548,7 +27555,7 @@ templated overload. -- end note]
 
  • 
 
 
    
-Change 20.8.12.2.1 [unique.ptr.single.ctor]:
+Change 20.8.9.2.1 [unique.ptr.single.ctor]:
 
    
 
 
    
@@ -27582,7 +27589,7 @@ required).
 
 
    
 
    674. shared_ptr interface changes for consistency with N1856
    
-
    Section: 20.8.13.2 [util.smartptr.shared] Status: CD1
+
    Section: 20.8.10.2 [util.smartptr.shared] Status: CD1
  Submitter: Peter Dimov Opened: 2007-05-05  Last modified: 2008-09-26
    
 
    View other active issues in [util.smartptr.shared].
    
 
    View all other issues in [util.smartptr.shared].
    
@@ -27598,7 +27605,7 @@ and to interoperate with unique_ptr as it does with auto_ptr.
 
    Proposed resolution:
    
 
 
    
-Change 20.8.13.2 [util.smartptr.shared] as follows:
+Change 20.8.10.2 [util.smartptr.shared] as follows:
 
    
 
 
    
@@ -27612,7 +27619,7 @@ template<class Y, class D> shared_ptr& operator=(unique_ptr<Y,D>
 
    
 
 
    
-Change 20.8.13.2.1 [util.smartptr.shared.const] as follows:
+Change 20.8.10.2.1 [util.smartptr.shared.const] as follows:
 
    
 
 
    
@@ -27620,7 +27627,7 @@ Change 20.8.13.2.1 [util.smartptr.shared.const] as follows:
 
    
 
 
    
-Add to 20.8.13.2.1 [util.smartptr.shared.const]:
+Add to 20.8.10.2.1 [util.smartptr.shared.const]:
 
    
 
 
    
@@ -27641,7 +27648,7 @@ Add to 20.8.13.2.1 [util.smartptr.shared.const]:
 
    
 
 
    
-Change 20.8.13.2.3 [util.smartptr.shared.assign] as follows:
+Change 20.8.10.2.3 [util.smartptr.shared.assign] as follows:
 
    
 
 
    
@@ -27649,7 +27656,7 @@ Change 20.8.13.2.3 [util.smartptr.shared.assign] as follows:
 
    
 
 
    
-Add to 20.8.13.2.3 [util.smartptr.shared.assign]:
+Add to 20.8.10.2.3 [util.smartptr.shared.assign]:
 
    
 
 
    
@@ -28085,14 +28092,14 @@ Change 23.3.6.2 [vector.capacity], p11:
 
 
    
 
    680. move_iterator operator-> return
    
-
    Section: 24.5.3.1 [move.iterator] Status: CD1
+
    Section: 24.5.2.1 [move.iterator] Status: CD1
  Submitter: Howard Hinnant Opened: 2007-06-11  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
 move_iterator's operator-> return type pointer
 does not consistently match the type which is returned in the description
-in 24.5.3.2.5 [move.iter.op.ref].
+in 24.5.2.2.5 [move.iter.op.ref].
 
    
 
 
    template <class Iterator>
@@ -28136,7 +28143,7 @@ finds a non-class type, the second solution avoids the issue of an overloaded
 
 
    Proposed resolution:
    
 
    
-Change the synopsis in 24.5.3.1 [move.iterator]:
+Change the synopsis in 24.5.2.1 [move.iterator]:
 
    
 
 
    typedef typename iterator_traits<Iterator>::pointer pointer;
@@ -28149,12 +28156,13 @@ Change the synopsis in 24.5.3.1 [move.iterator]:
 
 
    
 
    681. Operator functions impossible to compare are defined in [re.submatch.op]
    
-
    Section: 28.10.2 [re.submatch.op] Status: CD1
+
    Section: 28.9.2 [re.submatch.op] Status: CD1
  Submitter: Nozomu Katoo Opened: 2007-05-27  Last modified: 2009-05-01
    
+
    View all other issues in [re.submatch.op].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-In 28.10.2 [re.submatch.op] of N2284, 
+In 28.9.2 [re.submatch.op] of N2284, 
 operator functions numbered 31-42 seem impossible to compare. E.g.: 
 
    
 
@@ -28197,13 +28205,13 @@ The LWG voted to accelerate this issue to Ready status to be voted into the WP a
 
 
    
 
    682. basic_regex ctor takes InputIterator or ForwardIterator?
    
-
    Section: 28.9.2 [re.regex.construct] Status: CD1
+
    Section: 28.8.2 [re.regex.construct] Status: CD1
  Submitter: Eric Niebler Opened: 2007-06-03  Last modified: 2009-05-01
    
 
    View all other issues in [re.regex.construct].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
 
    
-Looking at N2284, 28.9 [re.regex], p3 basic_regex class template synopsis shows this 
+Looking at N2284, 28.8 [re.regex], p3 basic_regex class template synopsis shows this 
 constructor: 
 
    
 
    template <class InputIterator>
@@ -28212,7 +28220,7 @@ constructor:
 
    
 
 
    
-In 28.9.2 [re.regex.construct], p15, the constructor appears with this signature: 
+In 28.8.2 [re.regex.construct], p15, the constructor appears with this signature: 
 
    
 
 
    template <class ForwardIterator>
@@ -28259,7 +28267,7 @@ The LWG voted to accelerate this issue to Ready status to be voted into the WP a
 
 
    
 
    685. reverse_iterator/move_iterator difference has invalid signatures
    
-
    Section: 24.5.1.2.19 [reverse.iter.opdiff], 24.5.3.2.14 [move.iter.nonmember] Status: CD1
+
    Section: 24.5.1.2.19 [reverse.iter.opdiff], 24.5.2.2.14 [move.iter.nonmember] Status: CD1
  Submitter: Bo Persson Opened: 2007-06-10  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -28291,7 +28299,7 @@ implementation choose one of them? Which one?
 
    
 
    
 The same problem now also appears in operator-() for move_iterator
-24.5.3.2.14 [move.iter.nonmember]. 
+24.5.2.2.14 [move.iter.nonmember]. 
 
    
 
 
@@ -28327,7 +28335,7 @@ Change 24.5.1.2.19 [reverse.iter.opdiff]:
 
 
 
    
-Change the synopsis in 24.5.3.1 [move.iterator]:
+Change the synopsis in 24.5.2.1 [move.iterator]:
 
    
 
 
    
@@ -28339,7 +28347,7 @@ Change the synopsis in 24.5.3.1 [move.iterator]:
 
    
 
 
    
-Change 24.5.3.2.14 [move.iter.nonmember]:
+Change 24.5.2.2.14 [move.iter.nonmember]:
 
    
 
 
    
@@ -28368,7 +28376,7 @@ goes in.
 
 
    
 
    687. shared_ptr conversion constructor not constrained
    
-
    Section: 20.8.13.2.1 [util.smartptr.shared.const], 20.8.13.3.1 [util.smartptr.weak.const] Status: CD1
+
    Section: 20.8.10.2.1 [util.smartptr.shared.const], 20.8.10.3.1 [util.smartptr.weak.const] Status: CD1
  Submitter: Peter Dimov Opened: 2007-05-10  Last modified: 2009-02-02
    
 
    View other active issues in [util.smartptr.shared.const].
    
 
    View all other issues in [util.smartptr.shared.const].
    
@@ -28398,7 +28406,7 @@ overload resolution when the pointer types are compatible.
 
 
    Proposed resolution:
    
 
    
-In 20.8.13.2.1 [util.smartptr.shared.const], change:
+In 20.8.10.2.1 [util.smartptr.shared.const], change:
 
    
 
 
    
@@ -28409,7 +28417,7 @@ to T*.
 
    
 
 
    
-In 20.8.13.3.1 [util.smartptr.weak.const], change:
+In 20.8.10.3.1 [util.smartptr.weak.const], change:
 
    
 
 
    
@@ -28434,6 +28442,145 @@ overload resolution unless Y* shall be
 
 
 
    
+
    688. reference_wrapper, cref unsafe, allow binding to rvalues
    
+
    Section: 20.7.5.1 [refwrap.const] Status: WP
+ Submitter: Peter Dimov Opened: 2007-05-10  Last modified: 2009-07-18
    
+
    View all other issues in [refwrap.const].
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+
    
+A reference_wrapper can be constructed from an rvalue, either by using
+the constructor, or via cref (and ref in some corner cases). This leads
+to a dangling reference being stored into the reference_wrapper object.
+Now that we have a mechanism to detect an rvalue, we can fix them to
+disallow this source of undefined behavior.
+
    
+
+
    
+Also please see the thread starting at c++std-lib-17398 for some good discussion on this subject.
+
    
+
+
    [
+2009-05-09 Alisdair adds:
+]
    
+
+
+
    
+
    
+Now that ref/cref are constained that T must be an ObjectType, I do not
+believe there is any risk of binding ref to a temporary (which would rely on
+deducing T to be an rvalue reference type)
+
    
+
    
+However, the problem for cref remains, so I recommend retaining that deleted
+overload.
+
    
+
    
+
+
    [
+2009-05-10 Howard adds:
+]
    
+
+
+
    
+
    
+Without:
+
    
+
+
    template <class T> void ref(const T&& t) = delete;
+
    
+
    
+I believe this program will compile:
+
    
+
+
    #include <functional>
+
+struct A {};
+
+const A source() {return A();}
+
+int main()
+{
+   std::reference_wrapper<const A> r = std::ref(source());
+}
+
    
+
    
+I.e. in:
+
    
+
    template <ObjectType T> reference_wrapper<T> ref(T& t);
+
    
+
+
    
+this:
+
    
+
+
    ref(source())
+
    
+
    
+deduces T as const A, and so:
+
    
+
+
    ref(const A& t)
+
    
+
+
    
+will bind to a temporary (tested with a pre-concepts rvalue-ref enabled compiler).
+
    
+
    
+Therefore I think we still need the ref-protection.  I respectfully disagree with Alisdair's
+comment and am in favor of the proposed wording as it stands.  Also, CWG 606
+(noted below) has now been "favorably" resolved.
+
    
+
+
    
+
+
    [
+Batavia (2009-05):
+]
    
+
+
    
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
    
+
+
+
    Proposed resolution:
    
+
    
+In 20.7 [function.objects], add the following two signatures to the synopsis:
+
    
+
+
    template <class T> void ref(const T&& t) = delete;
+template <class T> void cref(const T&& t) = delete;
+
    
+
+
+
+
    [
+N2292
+addresses the first part of the resolution but not the second.
+]
    
+
+
+
    [
+Bellevue:  Doug noticed problems with the current wording.
+]
    
+
+
+
    [
+post Bellevue:  Howard and Peter provided revised wording.
+]
    
+
+
+
    [
+This resolution depends on a "favorable" resolution of CWG 606:  that is,
+the "special deduction rule" is disabled with the const T&& pattern.
+]
    
+
+
+
+
+
+
    
 
    689. reference_wrapper constructor overly constrained
    
 
    Section: 20.7.5.1 [refwrap.const] Status: CD1
  Submitter: Peter Dimov Opened: 2007-05-10  Last modified: 2008-09-26
    
@@ -28948,7 +29095,6 @@ To 19.5.5.2 [syserr.syserr.members] Class system_error members add:
 
    699. N2111 changes min/max
    
 
    Section: 26.5 [rand] Status: CD1
  Submitter: P.J. Plauger Opened: 2007-07-01  Last modified: 2008-09-26
    
-
    View other active issues in [rand].
    
 
    View all other issues in [rand].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -28988,6 +29134,7 @@ The LWG voted to accelerate this issue to Ready status to be voted into the WP a
 
    700. N1856 defines struct identity
    
 
    Section: 20.3.2 [forward] Status: CD1
  Submitter: P.J. Plauger Opened: 2007-07-01  Last modified: 2008-09-26
    
+
    View other active issues in [forward].
    
 
    View all other issues in [forward].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -29225,7 +29372,7 @@ Moved from Pending NAD Editorial to Review.  The proposed wording appears to be
 
 
    
 
    710. Missing postconditions
    
-
    Section: 20.8.13.2 [util.smartptr.shared] Status: CD1
+
    Section: 20.8.10.2 [util.smartptr.shared] Status: CD1
  Submitter: Peter Dimov Opened: 2007-08-24  Last modified: 2008-09-26
    
 
    View other active issues in [util.smartptr.shared].
    
 
    View all other issues in [util.smartptr.shared].
    
@@ -29259,7 +29406,7 @@ editor should consider rewording "If w is the return value...", e. g. as
 
 
    Proposed resolution:
    
 
    
-Add to 20.8.13.2.1 [util.smartptr.shared.const]:
+Add to 20.8.10.2.1 [util.smartptr.shared.const]:
 
    
 
 
    
@@ -29275,7 +29422,7 @@ shall be empty. r.get() == 0.
 
    
 
 
    
-Add to 20.8.13.2.10 [util.smartptr.shared.cast]:
+Add to 20.8.10.2.10 [util.smartptr.shared.cast]:
 
    
 
 
    
@@ -29318,7 +29465,7 @@ the aliasing constructor as follows:
 
    
 
 
    
-Change 20.8.13.2.10 [util.smartptr.shared.cast]:
+Change 20.8.10.2.10 [util.smartptr.shared.cast]:
 
    
 
 
    
@@ -29500,7 +29647,6 @@ template<class ForwardIterator, class Size, class T,
 
    715. minmax_element complexity is too lax
    
 
    Section: 25.5.7 [alg.min.max] Status: CD1
  Submitter: Matt Austern Opened: 2007-08-30  Last modified: 2008-09-26
    
-
    View other active issues in [alg.min.max].
    
 
    View all other issues in [alg.min.max].
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -29974,7 +30120,7 @@ straw poll unanimous move to Ready.
 
 
    Proposed resolution:
    
 
    
-Change the synopsis under 20.8.12 [unique.ptr] p2:
+Change the synopsis under 20.8.9 [unique.ptr] p2:
 
    
 
 
    ...
@@ -29989,7 +30135,7 @@ template<class T, class D> class unique_ptr<T[], D>;
 
    
 
 
    
-Remove the entire section 20.8.12.1.3 [unique.ptr.dltr.dflt2] default_delete<T[N]>.
+Remove the entire section  [unique.ptr.dltr.dflt2] default_delete<T[N]>.
 
    
 
 
    
@@ -30005,7 +30151,7 @@ and its subsections:  [unique.ptr.compiletime.dtor],  [unique.ptr.compiletime.ob
 
 
    
 
    743. rvalue swap for shared_ptr
    
-
    Section: 20.8.13.2.9 [util.smartptr.shared.spec] Status: CD1
+
    Section: 20.8.10.2.9 [util.smartptr.shared.spec] Status: CD1
  Submitter: Howard Hinnant Opened: 2007-10-10  Last modified: 2008-09-26
    
 
    View all issues with CD1 status.
    
 
    Discussion:
    
@@ -30047,7 +30193,7 @@ Adopt issue as written.
 
 
    Proposed resolution:
    
 
    
-Change the synopsis in 20.8.13.2 [util.smartptr.shared]:
+Change the synopsis in 20.8.10.2 [util.smartptr.shared]:
 
    
 
 
    void swap(shared_ptr&& r);
@@ -30058,14 +30204,14 @@ template<class T> void swap(shared_ptr<T>& a, shared_ptr<T>
 
    
 
 
    
-Change 20.8.13.2.4 [util.smartptr.shared.mod]:
+Change 20.8.10.2.4 [util.smartptr.shared.mod]:
 
    
 
 
    void swap(shared_ptr&& r);
 
    
 
 
    
-Change 20.8.13.2.9 [util.smartptr.shared.spec]:
+Change 20.8.10.2.9 [util.smartptr.shared.spec]:
 
    
 
 
    template<class T> void swap(shared_ptr<T>& a, shared_ptr<T>& b);
@@ -30340,6 +30486,7 @@ requirements on allocator types.
 
    753. Move constructor in draft
    
 
    Section: X [utility.arg.requirements] Status: WP
  Submitter: Yechezkel Mett Opened: 2007-10-14  Last modified: 2009-03-09
    
+
    View other active issues in [utility.arg.requirements].
    
 
    View all other issues in [utility.arg.requirements].
    
 
    View all issues with WP status.
    
 
    Discussion:
    
@@ -30557,7 +30704,7 @@ allow latitude for implementation-specific optimizations.
 
 
    
 
    758. shared_ptr and nullptr
    
-
    Section: 20.8.13.2 [util.smartptr.shared] Status: WP
+
    Section: 20.8.10.2 [util.smartptr.shared] Status: WP
  Submitter: Joe Gottman Opened: 2007-10-31  Last modified: 2009-03-09
    
 
    View other active issues in [util.smartptr.shared].
    
 
    View all other issues in [util.smartptr.shared].
    
@@ -30656,7 +30803,7 @@ The following wording changes are less intrusive:
 
    
 
 
    
-In 20.8.13.2.1 [util.smartptr.shared.const], add:
+In 20.8.10.2.1 [util.smartptr.shared.const], add:
 
    
 
 
    shared_ptr(nullptr_t);
@@ -30735,7 +30882,7 @@ Disposition: move to review. The review should check the wording in the then-cur
 
 
    Proposed resolution:
    
 
    
-In 20.8.13.2 [util.smartptr.shared] p4, add to the definition/synopsis
+In 20.8.10.2 [util.smartptr.shared] p4, add to the definition/synopsis
 of shared_ptr:
 
    
 
@@ -30752,7 +30899,7 @@ template<class Y, class D, class A> shared_ptr(Y* p, D d, A a);
 
    
 
 
    
-In 20.8.13.2.1 [util.smartptr.shared.const] add:
+In 20.8.10.2.1 [util.smartptr.shared.const] add:
 
    
 
 
    template<class D> shared_ptr(nullptr_t p, D d);
@@ -30768,11 +30915,11 @@ template<class Y, class D, class A> shared_ptr(Y* p, D d, A a);
 
    
 
 
    
-(reusing the following paragraphs 20.8.13.2.1 [util.smartptr.shared.const]/9-13 that speak of p.)
+(reusing the following paragraphs 20.8.10.2.1 [util.smartptr.shared.const]/9-13 that speak of p.)
 
    
 
 
    
-In 20.8.13.2.1 [util.smartptr.shared.const]/10,  change
+In 20.8.10.2.1 [util.smartptr.shared.const]/10,  change
 
    
 
 
    
@@ -30906,7 +31053,7 @@ Bellevue:  Editorial note: the "(unique)" differs from map.
 
 
    
 
    762. std::unique_ptr requires complete type?
    
-
    Section: 20.8.12 [unique.ptr] Status: CD1
+
    Section: 20.8.9 [unique.ptr] Status: CD1
  Submitter: Daniel Krügler Opened: 2007-11-30  Last modified: 2008-09-26
    
 
    View all other issues in [unique.ptr].
    
 
    View all issues with CD1 status.
    
@@ -30952,7 +31099,7 @@ The specialization unique_ptr<T[]> has some more restrictive cons
 type-completeness on T than unique_ptr<T>. The following proposed wordings
 try to cope with that. If the committee sees less usefulness on relaxed
 constraints on unique_ptr<T[]>, the alternative would be to stop this relaxation
-e.g. by adding one further bullet to 20.8.12.3 [unique.ptr.runtime]/1:
+e.g. by adding one further bullet to 20.8.9.3 [unique.ptr.runtime]/1:
 "T shall be a complete type, if used as template argument of
 unique_ptr<T[], D>
 
    
@@ -30971,7 +31118,7 @@ current specification of unique_ptr.
 
      
 
    1. 
 
      
-In 20.8.12 [unique.ptr]/2 add as the last sentence to the existing para:
+In 20.8.9 [unique.ptr]/2 add as the last sentence to the existing para:
 
      
 
 
      
@@ -30990,7 +31137,7 @@ function. -- end note ]
 
 
    2. 
 
      
-20.8.12.2.1 [unique.ptr.single.ctor]/1: No changes necessary.
+20.8.9.2.1 [unique.ptr.single.ctor]/1: No changes necessary.
 
      
 
 
      
@@ -31004,7 +31151,7 @@ The current wording says just this.
 
 
    3. 
 
      
-In 20.8.12.2.1 [unique.ptr.single.ctor]/5 change the requires clause to say:
+In 20.8.9.2.1 [unique.ptr.single.ctor]/5 change the requires clause to say:
 
      
 
 
      
@@ -31041,7 +31188,7 @@ again requires Completeness of Y, if !SameType<X, Y>
 
 
    4. 
 
      
-Merge 20.8.12.2.1 [unique.ptr.single.ctor]/12+13 thereby removing the sentence
+Merge 20.8.9.2.1 [unique.ptr.single.ctor]/12+13 thereby removing the sentence
 of 12, but transferring the "requires" to 13:
 
      
 
@@ -31060,10 +31207,10 @@ pointer and the D deleter are well-formed and well-defined.
 
      5. 
 
 
    5. 
-20.8.12.2.1 [unique.ptr.single.ctor]/17: No changes necessary.
+20.8.9.2.1 [unique.ptr.single.ctor]/17: No changes necessary.
 
      6. 
 
    6. 
-
      20.8.12.2.1 [unique.ptr.single.ctor]/21:
      
+
      20.8.9.2.1 [unique.ptr.single.ctor]/21:
      
 
 
      
 Requires: If D is not a reference type, construction of
@@ -31086,7 +31233,7 @@ e.g. "U shall be a complete type."
 
 
    7. 
 
      
-20.8.12.2.2 [unique.ptr.single.dtor]: Just before p1 add a new paragraph:
+20.8.9.2.2 [unique.ptr.single.dtor]: Just before p1 add a new paragraph:
 
      
 
      
 
      
@@ -31105,7 +31252,7 @@ type-completeness of T is delegated to this expression.
 
 
    8. 
 
      
-20.8.12.2.3 [unique.ptr.single.asgn]/1: No changes necessary, except the
+20.8.9.2.3 [unique.ptr.single.asgn]/1: No changes necessary, except the
 current editorial issue, that "must shall" has to be changed to
 "shall", but this change is not a special part of this resolution.
 
      
@@ -31119,7 +31266,7 @@ further requirements on the requirements of the effects clause
 
 
    9. 
 
      
-20.8.12.2.3 [unique.ptr.single.asgn]/6:
+20.8.9.2.3 [unique.ptr.single.asgn]/6:
 
      
 
 
      
@@ -31140,7 +31287,7 @@ is true, see (6)+(8).
 
 
    10. 
 
      
-20.8.12.2.3 [unique.ptr.single.asgn]/11: No changes necessary.
+20.8.9.2.3 [unique.ptr.single.asgn]/11: No changes necessary.
 
      
 
      [
 N.B.: Delegation to requirements of effects clause is sufficient.
@@ -31149,7 +31296,7 @@ N.B.: Delegation to requirements of effects clause is sufficient.
 
      11. 
 
 
    11. 
-20.8.12.2.4 [unique.ptr.single.observers]/1+4+7+9+11:
+20.8.9.2.4 [unique.ptr.single.observers]/1+4+7+9+11:
 
      12. 
 
 
      
@@ -31160,12 +31307,12 @@ N.B.: Delegation to requirements of effects clause is sufficient.
 
      
 
 
    12. 
-20.8.12.2.5 [unique.ptr.single.modifiers]/1: No changes necessary.
+20.8.9.2.5 [unique.ptr.single.modifiers]/1: No changes necessary.
 
      13. 
 
 
    13. 
 
      
-20.8.12.2.5 [unique.ptr.single.modifiers]/4: Just before p. 4 add a new paragraph:
+20.8.9.2.5 [unique.ptr.single.modifiers]/4: Just before p. 4 add a new paragraph:
 
      
 
      
 Requires: The expression get_deleter()(get()) shall be well-formed,
@@ -31174,12 +31321,12 @@ shall have well-defined behavior, and shall not throw exceptions.
 
      14. 
 
 
    14. 
-20.8.12.2.5 [unique.ptr.single.modifiers]/7: No changes necessary.
+20.8.9.2.5 [unique.ptr.single.modifiers]/7: No changes necessary.
 
      15. 
 
 
    15. 
 
      
-20.8.12.3 [unique.ptr.runtime]: Add one additional bullet on paragraph 1:
+20.8.9.3 [unique.ptr.runtime]: Add one additional bullet on paragraph 1:
 
      
 
 
      
@@ -31210,6 +31357,156 @@ post Bellevue: Daniel provided revised wording.
 
 
 
      
+
      765. more on iterator validity
      
+
      Section: 24.2 [iterator.concepts] Status: WP
+ Submitter: Martin Sebor Opened: 2007-12-14  Last modified: 2009-07-18
      
+
      View other active issues in [iterator.concepts].
      
+
      View all other issues in [iterator.concepts].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+       
      
+
+Issue 278
+defines the meaning of the term "invalid iterator" as one that may be
+singular.
+
+       
      
+       
      
+
+Consider the following code:
+
+       
      
+       
         std::deque<int> x, y;
+   std::deque<int>::iterator i = x.end(), j = y.end();
+   x.swap(y);
+       
      
+       
      
+
+Given that swap() is required not to invalidate iterators
+and using the definition above, what should be the expected result of
+comparing i and j to x.end()
+and y.end(), respectively, after the swap()?
+
+       
      
+       
      
+
+I.e., is the expression below required to evaluate
+to true?
+
+       
      
+       
         i == y.end() && j == x.end()
+       
      
+       
      
+
+(There are at least two implementations where the expression
+returns false.)
+
+       
      
+       
      
+
+More generally, is the definition introduced in issue 278 meant to
+make any guarantees about whether iterators actually point to the same
+elements or be associated with the same containers after a
+non-invalidating operation as they did before?
+
+       
      
+       
      
+
+Here's a motivating example intended to demonstrate the importance of
+the question:
+
+       
      
+       
         Container x, y ({ 1, 2});   // pseudocode to initialize y with { 1, 2 }
+   Container::iterator i = y.begin() + 1;
+   Container::iterator j = y.end();
+   std::swap(x, y);
+   std::find(i, j, 3);
+       
      
+       
      
+
+swap() guarantees that i and j
+continue to be valid. Unless the spec says that even though they are
+valid they may no longer denote a valid range the code above must be
+well-defined. Expert opinions on this differ as does the behavior of
+popular implementations for some standard Containers.
+
+       
      
+
      [
+San Francisco:
+]
      
+
+
+
      
+
      Pablo: add a note to the last bullet of paragraph 11 of 23.1.1
+clarifying that the end() iterator doesn't refer to an element and that
+it can therefore be invalidated.
+
      
+
      
+Proposed wording:
+
      
+
      
+[Note: The end() iterator does not refer to any element and can
+therefore be invalidated. -- end note]
+
      
+
      
+Howard will add this proposed wording to the issue and then move it to Review.
+
      
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+
      
+Lawrence: suggestion: "Note: The end() iterator does not refer to any element"
+
      
+
      
+Walter: "Note: The end() iterator can nevertheless be invalidated,
+because it does not refer to any element."
+
      
+
      
+Nick: "The end() iterator does not refer to any element. It is therefore
+subject to being invalidated."
+
      
+
      
+Consensus: go with Nick
+
      
+
      
+With that update, Recommend Tentatively Ready.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Add to 23.2.1 [container.requirements.general], p11:
+
      
+
+
      
+
      
+Unless otherwise specified (see 23.1.4.1, 23.1.5.1, 23.2.2.3, and
+23.2.6.4) all container types defined in this Clause meet the following
+additional requirements:
+
      
+
        
+
      • ...
        • 
+
      • 
+no swap() function invalidates any references, pointers, or
+iterators referring to the elements of the containers being swapped.
+[Note: The end() iterator does not refer to any element. It is therefore
+subject to being invalidated. -- end note]
+
        • 
+
      
+
      
+
+
+
+
+
+
      
 
      766. Inconsistent exception guarantees between ordered and unordered associative containers
      
 
      Section: 23.2 [container.requirements], 23.2.5.1 [unord.req.except] Status: CD1
  Submitter: Ion Gaztañaga Opened: 2007-12-22  Last modified: 2008-09-26
      
@@ -31499,7 +31796,6 @@ Change the synopsis in 29.5.3 [atomics.types.generic]:
 
      769. std::function should use nullptr_t instead of "unspecified-null-pointer-type"
      
 
      Section: 20.7.16.2 [func.wrap.func] Status: CD1
  Submitter: Daniel Krügler Opened: 2008-01-10  Last modified: 2008-09-26
      
-
      View other active issues in [func.wrap.func].
      
 
      View all other issues in [func.wrap.func].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
@@ -32084,6 +32380,7 @@ Set state to Review given substitution of "fill" for "assign".
 
      777. Atomics Library Issue
      
 
      Section: 29.6 [atomics.types.operations] Status: CD1
  Submitter: Lawrence Crowl Opened: 2008-01-21  Last modified: 2008-09-26
      
+
      View other active issues in [atomics.types.operations].
      
 
      View all other issues in [atomics.types.operations].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
@@ -32839,7 +33136,7 @@ Part B: Technically correct, save for typo. Rendered moot by the concept proposa
 (N2620) NAD (editorial).
 
      
 
      
-Part C: We agree; this is consistent with the resolution of issue 721.
+Part C: We agree; this is consistent with the resolution of issue 721.
 
      
 
      
 Howard: please ping Beman, asking him to clear away parts A and B from
@@ -33335,9 +33632,8 @@ intuitive. There are no uses of errc in the current C++ standard.
 
 
      
 
      806. unique_ptr::reset effects incorrect, too permissive
      
-
      Section: 20.8.12.2.5 [unique.ptr.single.modifiers] Status: CD1
+
      Section: 20.8.9.2.5 [unique.ptr.single.modifiers] Status: CD1
  Submitter: Peter Dimov Opened: 2008-03-13  Last modified: 2008-09-26
      
-
      View other active issues in [unique.ptr.single.modifiers].
      
 
      View all other issues in [unique.ptr.single.modifiers].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
@@ -33389,7 +33685,7 @@ scenario, as it definitely doesn't when p and q are separate.
 
      Proposed resolution:
      
 
 
      
-Change 20.8.12.2.5 [unique.ptr.single.modifiers]:
+Change 20.8.9.2.5 [unique.ptr.single.modifiers]:
 
      
 
 
      
@@ -33401,7 +33697,7 @@ Change 20.8.12.2.5 [unique.ptr.single.modifiers]:
 
      
 
 
      
-Change 20.8.12.3.3 [unique.ptr.runtime.modifiers]:
+Change 20.8.9.3.3 [unique.ptr.runtime.modifiers]:
 
      
 
 
      
@@ -33454,6 +33750,7 @@ or assignment of one of the types in Types throws an exception.
 
      808. [forward] incorrect redundant specification
      
 
      Section: 20.3.2 [forward] Status: CD1
  Submitter: Jens Maurer Opened: 2008-03-13  Last modified: 2008-09-26
      
+
      View other active issues in [forward].
      
 
      View all other issues in [forward].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
@@ -33623,15 +33920,125 @@ Add the following to 25.4.3 [alg.swap]:
 
 
 
      
+
      810. Missing traits dependencies in operational semantics of extended manipulators
      
+
      Section: 27.7.4 [ext.manip] Status: WP
+ Submitter: Daniel Krügler Opened: 2008-03-01  Last modified: 2009-07-18
      
+
      View all other issues in [ext.manip].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+The recent draft (as well as the original proposal n2072) uses an
+operational semantic
+for get_money ([ext.manip]/4) and put_money ([ext.manip]/6), which uses
+
      
+
+
      istreambuf_iterator<charT>
+
      
+
+
      
+and
+
      
+
+
      ostreambuf_iterator<charT>
+
      
+
+
      
+resp, instead of the iterator instances, with explicitly provided
+traits argument (The operational semantic defined by f is also traits
+dependent). This is an obvious oversight because both *stream_buf
+c'tors expect a basic_streambuf<charT,traits> as argument.
+
      
+
      
+The same problem occurs within the get_time and put_time semantic 
+where additional to the problem we
+have an editorial issue in get_time (streambuf_iterator instead of
+istreambuf_iterator).
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+This appears to be an issue of presentation.
+
      
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+In 27.7.4 [ext.manip]/4 within function f replace the first line
+
      
+
+
      template <class charT, class traits, class moneyT> 
+void f(basic_ios<charT, traits>& str, moneyT& mon, bool intl) { 
+   typedef istreambuf_iterator<charT, traits> Iter;
+   ...
+
      
+
+
      
+In 27.7.4 [ext.manip]/5 remove the first template charT parameter:
+
      
+
+
      template <class charT, class moneyT> unspecified put_money(const moneyT& mon, bool intl = false);
+
      
+
+
      
+In 27.7.4 [ext.manip]/6 within function f replace the first line
+
      
+
+
      template <class charT, class traits, class moneyT> 
+void f(basic_ios<charT, traits>& str, const moneyT& mon, bool intl) { 
+  typedef ostreambuf_iterator<charT, traits> Iter;
+  ...
+
      
+
+
      
+In 27.7.4 [ext.manip]/8 within function f replace the first line
+
      
+
+
      template <class charT, class traits> 
+void f(basic_ios<charT, traits>& str, struct tm *tmb, const charT *fmt) { 
+  typedef istreambuf_iterator<charT, traits> Iter;
+  ...
+
      
+
+
      
+In 27.7.4 [ext.manip]/10 within function f replace the first line
+
      
+
+
      template <class charT, class traits> 
+void f(basic_ios<charT, traits>& str, const struct tm *tmb, const charT *fmt) { 
+  typedef ostreambuf_iterator<charT, traits> Iter;
+  ...
+
      
+
+
      
+In 27.7 [iostream.format], Header <iomanip> synopsis change:
+
      
+
+
      template <class charT, class moneyT> T8 put_money(const moneyT& mon, bool intl = false);
+
      
+
+
+
+
+
+
      
 
      813. "empty" undefined for shared_ptr
      
-
      Section: 20.8.13.2 [util.smartptr.shared] Status: CD1
+
      Section: 20.8.10.2 [util.smartptr.shared] Status: CD1
  Submitter: Matt Austern Opened: 2008-02-26  Last modified: 2008-09-26
      
 
      View other active issues in [util.smartptr.shared].
      
 
      View all other issues in [util.smartptr.shared].
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
 
      
-Several places in 20.8.13.2 [util.smartptr.shared] refer to an "empty" shared_ptr.
+Several places in 20.8.10.2 [util.smartptr.shared] refer to an "empty" shared_ptr.
 However, that term is nowhere defined. The closest thing we have to a
 definition is that the default constructor creates an empty shared_ptr
 and that a copy of a default-constructed shared_ptr is empty. Are any
@@ -33753,7 +34160,7 @@ Alisdair's wording is fine.
 
 
      Proposed resolution:
      
 
      
-Append the following sentance to 20.8.13.2 [util.smartptr.shared]
+Append the following sentance to 20.8.10.2 [util.smartptr.shared]
 
      
 
      
 The shared_ptr class template stores a pointer, usually obtained
@@ -33769,6 +34176,66 @@ a pointer is said to be empty.
 
 
 
      
+
      814. vector<bool>::swap(reference, reference) not defined
      
+
      Section: 23.3.7 [vector.bool] Status: WP
+ Submitter: Alisdair Meredith Opened: 2008-03-17  Last modified: 2009-07-18
      
+
      View all other issues in [vector.bool].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+vector<bool>::swap(reference, reference) has no definition.
+
      
+
+
      [
+San Francisco:
+]
      
+
+
+
      
+Move to Open. Alisdair to provide a resolution.
+
      
+
+
      [
+Post Summit Daniel provided wording.
+]
      
+
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Just after 23.3.7 [vector.bool]/5 add the following prototype and description:
+
      
+
+
      
+
      
+static void swap(reference x, reference y);
+
      
+
      
+
      
+-6- Effects: Exchanges the contents of x and y as-if by:
+
      
+
      
+bool b = x;
+x = y;
+y = b;
+
      
+
      
+
      
+
+
+
+
+
+
      
 
      818. wording for memory ordering
      
 
      Section: 29.3 [atomics.order] Status: CD1
  Submitter: Jens Maurer Opened: 2008-03-22  Last modified: 2008-09-26
      
@@ -34124,7 +34591,7 @@ Pete will make the required editorial tweaks to rectify this.
 
 
      
 
      821. Minor cleanup : unique_ptr
      
-
      Section: 20.8.12.3.3 [unique.ptr.runtime.modifiers] Status: WP
+
      Section: 20.8.9.3.3 [unique.ptr.runtime.modifiers] Status: WP
  Submitter: Alisdair Meredith Opened: 2008-03-30  Last modified: 2009-03-09
      
 
      View all issues with WP status.
      
 
      Discussion:
      
@@ -34153,7 +34620,7 @@ to be a stronger match than the deleted overload. Words...
 
 
      Proposed resolution:
      
 
      
-Add to class template definition in 20.8.12.3 [unique.ptr.runtime]
+Add to class template definition in 20.8.9.3 [unique.ptr.runtime]
 
      
 
 
      
@@ -34167,7 +34634,7 @@ void swap(unique_ptr&& u);
 
      
 
 
      
-Update 20.8.12.3.3 [unique.ptr.runtime.modifiers]
+Update 20.8.9.3.3 [unique.ptr.runtime.modifiers]
 
      
 
 
      
@@ -34197,75 +34664,6 @@ Note this wording incorporates resolutions for 823. identity<void> seems broken
-
      Section: 20.3.2 [forward] Status: CD1
- Submitter: Walter Brown Opened: 2008-04-09  Last modified: 2008-09-26
      
-
      View all other issues in [forward].
      
-
      View all issues with CD1 status.
      
-
      Discussion:
      
-
      
-N2588 seems to have added an operator() member function to the
-identity<> helper in 20.3.2 [forward].  I believe this change makes it no
-longer possible to instantiate identity<void>, as it would require
-forming a reference-to-void type as this operator()'s parameter type.
-
      
-
-
      
-Suggested resolution:  Specialize identity<void> so as not to require
-the member function's presence.
-
      
-
-
      [
-Sophia Antipolis:
-]
      
-
-
-
      
-
      
-Jens: suggests to add a requires clause to avoid specializing on void.
-
      
-
      
-Alisdair: also consider cv-qualified void.
-
      
-
      
-Alberto provided proposed wording.
-
      
-
      
-
-
-
      Proposed resolution:
      
-
      
-Change definition of identity in 20.3.2 [forward], paragraph 2, to:
-
      
-
-
      template <class T>  struct identity {
-    typedef T type;
-
-    requires ReferentType<T>
-      const T& operator()(const T& x) const;
-  };
-
      
-
      ...
      
-
        requires ReferentType<T>
-    const T& operator()(const T& x) const;
-
      
-
-
-
      Rationale:
      
-
      
-The point here is to able to write T& given T and ReferentType is
-precisely the concept that guarantees so, according to N2677
-(Foundational concepts). Because of this, it seems preferable than an
-explicit check for cv void using SameType/remove_cv as it was suggested
-in Sophia. In particular, Daniel remarked that there may be types other
-than cv void which aren't referent types (int[], perhaps?).
-
      
-
-
-
-
-
-
      
 
      824. rvalue ref issue with basic_string inserter
      
 
      Section: 21.4.8.9 [string.io] Status: CD1
  Submitter: Alisdair Meredith Opened: 2008-04-10  Last modified: 2008-09-26
      
@@ -34495,7 +34893,7 @@ Move 20.3.6 [template.bitset] to clause 20.
 
 
      
 
      843.  Reference Closure
      
-
      Section: 20.7.18.1 [func.referenceclosure.cons] Status: CD1
+
      Section: X [func.referenceclosure.cons] Status: CD1
  Submitter: Lawrence Crowl Opened: 2008-06-02  Last modified: 2008-09-26
      
 
      View all issues with CD1 status.
      
 
      Discussion:
      
@@ -34534,7 +34932,7 @@ to the implementation.
 
 
      Proposed resolution:
      
 
      
-In 20.7.18 [func.referenceclosure] Class template reference_closure,
+In  [func.referenceclosure] Class template reference_closure,
 replace the =delete in the copy assignment operator in the synopsis
 with =default.
 
      
@@ -34548,7 +34946,7 @@ with =default.
 
    
 
 
    
-In 20.7.18.1 [func.referenceclosure.cons] Construct, copy, destroy,
+In X [func.referenceclosure.cons] Construct, copy, destroy,
 add the member function description
 
    
 
@@ -34983,6 +35381,122 @@ Change the synopsis in 23.5.1 [unord.map], 23.5.2 [unord.multimap], and 23.5.4 [
 
 
 
    
+
    853. to_string needs updating with zero and one
    
+
    Section: 20.3.6 [template.bitset] Status: WP
+ Submitter: Howard Hinnant Opened: 2008-06-18  Last modified: 2009-07-18
    
+
    View other active issues in [template.bitset].
    
+
    View all other issues in [template.bitset].
    
+
    View all issues with WP status.
    
+
    Discussion:
    
+
    
+Issue 396 adds defaulted arguments to the to_string member, but neglects to update
+the three newer to_string overloads.
+
    
+
+
    [
+post San Francisco:
+]
    
+
+
+
    
+Daniel found problems with the wording and provided fixes.  Moved from Ready
+to Review.
+
    
+
+
    [
+Post Summit:
+]
    
+
+
+
    
+
    
+Alisdair: suggest to not repeat the default arguments in B, C, D
+(definition of to_string members)
+
    
+
    
+Walter: This is not really a definition.
+
    
+
    
+Consensus: Add note to the editor: Please apply editor's judgement
+whether default arguments should be repeated for B, C, D changes.
+
    
+
    
+Recommend Tentatively Ready.
+
    
+
    
+
+
    [
+2009-05-09:  See alternative solution in issue 1113.
+]
    
+
+
+
+
+
    Proposed resolution:
    
+
      
+
    1. 
+
      replace in 20.3.6 [template.bitset]/1 (class bitset)
+
      
+
      template <class charT, class traits>
+  basic_string<charT, traits, allocator<charT> >
+  to_string(charT zero = charT('0'), charT one = charT('1')) const;
+template <class charT>
+  basic_string<charT, char_traits<charT>, allocator<charT> >
+  to_string(charT zero = charT('0'), charT one = charT('1')) const;
+basic_string<char, char_traits<char>, allocator<char> >
+  to_string(char zero = '0', char one = '1') const;
+
      
+
      2. 
+
    2. 
+
      
+replace in 20.3.6.2 [bitset.members]/37
+
      
+
      template <class charT, class traits>
+  basic_string<charT, traits, allocator<charT> >
+  to_string(charT zero = charT('0'), charT one = charT('1')) const;
+
      
+
      
+37 Returns: to_string<charT, traits, allocator<charT> >(zero, one).
+
      
+
      
+
      3. 
+
    3. 
+
      
+replace in 20.3.6.2 [bitset.members]/38
+
      
+
+
      template <class charT>
+  basic_string<charT, char_traits<charT>, allocator<charT> >
+  to_string(charT zero = charT('0'), charT one = charT('1')) const;
+
      
+
      
+38 Returns: to_string<charT, char_traits<charT>, allocator<charT> >(zero, one).
+
      
+
      
+
      4. 
+
+
    4. 
+
      
+replace in 20.3.6.2 [bitset.members]/39
+
      
+
+
      basic_string<char, char_traits<char>, allocator<char> >
+  to_string(char zero = '0', char one = '1') const;
+
      
+
      
+39 Returns: to_string<char, char_traits<char>, allocator<char> >(zero, one).
+
      
+
      
+
      5. 
+
+
    
+
+
+
+
+
+
+
    
 
    856. Removal of aligned_union
    
 
    Section: 20.6.7 [meta.trans.other] Status: CD1
  Submitter: Jens Maurer Opened: 2008-06-12  Last modified: 2008-09-26
    
@@ -35022,7 +35536,7 @@ struct aligned_union;
 
 
    
 
    858. Wording for Minimal Support for Garbage Collection
    
-
    Section: 20.8.13.7 [util.dynamic.safety] Status: CD1
+
    Section: 20.8.10.7 [util.dynamic.safety] Status: CD1
  Submitter: Pete Becker  Opened: 2008-06-21  Last modified: 2008-09-26
    
 
    View all other issues in [util.dynamic.safety].
    
 
    View all issues with CD1 status.
    
@@ -35073,7 +35587,7 @@ to clarify the intent.
 
 
    Proposed resolution:
    
 
    
-In 20.8.13.7 [util.dynamic.safety]
+In 20.8.10.7 [util.dynamic.safety]
 (N2670,
 Minimal Support for Garbage Collection)
 
    
@@ -35144,20 +35658,20 @@ note    ]
 
 
    
 
    866. Qualification of placement new-expressions
    
-
    Section: 20.8.11 [specialized.algorithms], 20.8.13.2.6 [util.smartptr.shared.create] Status: WP
+
    Section: 20.8.8 [specialized.algorithms], 20.8.10.2.6 [util.smartptr.shared.create] Status: WP
  Submitter: Alberto Ganesh Barbati Opened: 2008-07-14  Last modified: 2009-03-09
    
 
    View all other issues in [specialized.algorithms].
    
 
    View all issues with WP status.
    
 
    Discussion:
    
 
    
 LWG issue 402 replaced "new" with "::new" in the placement
-new-expression in 20.8.6.1 [allocator.members]. I believe the rationale
+new-expression in 20.8.4.1 [allocator.members]. I believe the rationale
 given in 402 applies also to the following other contexts:
 
    
 
      
 
    • 
 
      
-in 20.8.11 [specialized.algorithms], all four algorithms unitialized_copy,
+in 20.8.8 [specialized.algorithms], all four algorithms unitialized_copy,
 unitialized_copy_n, unitialized_fill and unitialized_fill_n use
 the unqualified placement new-expression in some variation of the form:
 
      
@@ -35166,7 +35680,7 @@ the unqualified placement new-expression in some variation of the form:
 
      • 
 
    • 
 
      
-in 20.8.13.2.6 [util.smartptr.shared.create] there is a reference to the unqualified placement new-expression:
+in 20.8.10.2.6 [util.smartptr.shared.create] there is a reference to the unqualified placement new-expression:
 
      
 
      new  (pv)  T(std::forward<Args>(args)...),
 
      
@@ -35215,16 +35729,16 @@ Replace "new" with "::new" in:
 
      
 
        
 
      • 
-20.8.11.2 [uninitialized.copy], paragraphs 1 and 3
+20.8.8.2 [uninitialized.copy], paragraphs 1 and 3
 
        • 
 
      • 
-20.8.11.3 [uninitialized.fill]  paragraph 1
+20.8.8.3 [uninitialized.fill]  paragraph 1
 
        • 
 
      • 
-20.8.11.4 [uninitialized.fill.n] paragraph 1
+20.8.8.4 [uninitialized.fill.n] paragraph 1
 
        • 
 
      • 
-20.8.13.2.6 [util.smartptr.shared.create] once in paragraph 1 and twice in paragraph 2.
+20.8.10.2.6 [util.smartptr.shared.create] once in paragraph 1 and twice in paragraph 2.
 
        • 
 
      
 
@@ -35234,6 +35748,169 @@ Replace "new" with "::new" in:
 
 
 
      
+
      869. Bucket (local) iterators and iterating past end
      
+
      Section: 23.2.5 [unord.req] Status: WP
+ Submitter: Sohail Somani Opened: 2008-07-22  Last modified: 2009-07-18
      
+
      View other active issues in [unord.req].
      
+
      View all other issues in [unord.req].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+Is there any language in the current draft specifying the behaviour of the following snippet?
+
      
+
+
      unordered_set<int> s;
+unordered_set<int>::local_iterator it = s.end(0);
+
+// Iterate past end - the unspecified part
+it++;
+
      
+
+
      
+I don't think there is anything about s.end(n) being considered an
+iterator for the past-the-end value though (I think) it should be.
+
      
+
+
      [
+San Francisco:
+]
      
+
+
+
      
+We believe that this is not a substantive change, but the proposed
+change to the wording is clearer than what we have now.
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+Recommend Tentatively Ready.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change Table 97 "Unordered associative container requirements" in 23.2.5 [unord.req]:
+
      
+
+
      
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
      Table 97: Unordered associative container requirements
      expressionreturn typeassertion/note pre/post-conditioncomplexity
      b.begin(n)local_iterator
      const_local_iterator for const b.      		Pre: n shall be in the range [0,b.bucket_count()). Note: [b.begin(n), b.end(n)) is a
+valid range containing all of the elements in the nth bucket.
+b.begin(n) returns an iterator referring to the first element in the bucket.
+If the bucket is empty, then b.begin(n) == b.end(n).Constant
      b.end(n)local_iterator
      const_local_iterator for const b.      		Pre: n shall be in the range [0, b.bucket_count()).
+b.end(n) returns an iterator which is the past-the-end value for the bucket.Constant
      
+
      
+
+
+
+
+
+
+
      
+
      878. forward_list preconditions
      
+
      Section: 23.3.3 [forwardlist] Status: WP
+ Submitter: Martin Sebor Opened: 2008-08-23  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+       
      
+
+forward_list member functions that take
+a forward_list::iterator (denoted position in the
+function signatures) argument have the following precondition:
+
+       
      
+       
      
+
+Requires: position is dereferenceable or equal
+to before_begin().
+
+       
      
+       
      
+
+I believe what's actually intended is this:
+
+       
      
+       
      
+
+Requires: position is in the range
+[before_begin(), end()).
+
+       
      
+       
      
+
+That is, when it's dereferenceable, position must point
+into *this, not just any forward_list object.
+
+       
      
+
+
      [
+San Francisco:
+]
      
+
+
+
      
+Robert suggested alternate proposed wording which had large support.
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+
      
+Walter: "position is before_begin() or a dereferenceable": add "is" after the "or"
+
      
+
      
+With that minor update, Recommend Tentatively Ready.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+       
      
+
+Change the Requires clauses
+ [forwardlist] , p21, p24, p26, p29, and,
+23.3.3.5 [forwardlist.ops], p39, p43, p47
+as follows:
+
+       
      
+       
      
+
+Requires: position is before_begin() or is a
+dereferenceable
+iterator in the range [begin(), end())
+or equal to before_begin(). ...
+
+       
      
+   
+
+
+
+
      
 
      882. duration non-member arithmetic requirements
      
 
      Section: 20.9.3.5 [time.duration.nonmember] Status: CD1
  Submitter: Howard Hinnant Opened: 2008-09-08  Last modified: 2008-09-26
      
@@ -35436,6 +36113,364 @@ be an instantiation of duration. Diagnostic required.
 
 
 
      
+
      888. this_thread::yield too strong
      
+
      Section: 30.3.2 [thread.thread.this] Status: WP
+ Submitter: Lawrence Crowl Opened: 2008-09-15  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+I never thought I'd say this, but this_thread::yield seems to be too
+strong in specification.  The issue is that some systems distinguish
+between yielding to another thread in the same process and yielding
+to another process.  Given that the C++ standard only talks about
+a single program, one can infer that the specification allows yielding
+only to another thread within the same program.  Posix has no
+facility for that behavior.  Can you please file an issue to weaken
+the wording.  Perhaps "Offers the operating system the opportunity
+to reschedule."
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+Recommend move to Tentatively Ready.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change 30.3.2 [thread.thread.this]/3:
+
      
+
+
      
+
      void this_thread::yield();
+
      
+
      
+Effects: Offers the operating system implementation
+the opportunity to reschedule.
+another thread.
+
      
+
      
+
+
+
+
+
+
      
+
      890. Improving <system_error> initialization
      
+
      Section: 19.5.1 [syserr.errcat] Status: WP
+ Submitter: Beman Dawes Opened: 2008-09-14  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+The static const error_category objects generic_category and
+system_category in header <system_error> are currently declared:
+
      
+
+
      const error_category& get_generic_category();
+const error_category& get_system_category();
+
+static const error_category& generic_category = get_generic_category();
+static const error_category& system_category = get_system_category();
+
      
+
+
      
+This formulation has several problems:
+
      
+
+
        
+
      • 
+Implementation details are exposed, since initialization is specified in
+the interface. This over-constrains implementations without offsetting
+user benefits. The form of initialization specified may be less than
+maximally efficient on some platforms.
+
        • 
+
      • 
+Use of the objects is more expensive in terms of number of machine level
+instructions. See Implementation experience below.
+
        • 
+
      • 
+Depending on the compiler, some cost may be incurred by each translation unit
+that includes the header, even if the objects are not used. This is a
+common scenario in user code, since the header is included by other
+standard library headers. It should be mentioned that at least one
+compilers is able to optimize this cost away, however.
+
        • 
+
      
+
+
      
+IO streams uses a somewhat different formulation for iostream_category, but 
+still suffer much the same problems.
+
      
+
+
      
+The original plan was to eliminate these problems by applying the C++0x
+constexpr feature. See LWG issue 832. However, that approach turned out
+to be unimplementable, since it would require a constexpr object of a
+class with virtual functions, and that is not allowed by the core
+language.
+
      
+
+
      
+The proposed resolution was developed as an alternative. It mitigates the above 
+problems by removing initialization from the visible interface, allowing 
+implementations flexibility.
+
      
+
+
      
+Implementation experience:
+
      
+
+
      
+Prototype implementations of the current WP interface and proposed
+resolution interface were tested with recent Codegear, GCC, Intel, and Microsoft 
+compilers on Windows. The code generated by the Microsoft compiler was studied 
+at length; the WP and proposal versions generated very similar code. For both versions 
+the compiler did make use of static
+initialization; apparently the compiler applied an implicit constexpr
+where useful, even in cases where constexpr would not be permitted by
+the language!
+
      
+
+
      
+Acknowledgements:
+
      
+
+
      
+Martin Sebor, Chris Kohlhoff, and John Lakos provided useful ideas and comments on initialization issues.
+
      
+
+
      [
+San Francisco:
+]
      
+
+
+
      
+
      
+Martin: prefers not to create more file-scope static objects, and would
+like to see get_* functions instead.
+
      
+
      
+
+
+
      [Pre-Summit:]
      
+
+
      
+
+
+
      
+Beman: The proposed resolution has been reworked to remove the file-scope 
+static objects, per Martin's suggestions. The get_ prefix has been 
+eliminated from the function names as no longer necessary and to conform with 
+standard library naming practice.
+
      
+
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+Agreement that this is wise and essential, text provided works and has
+been implemented. Seems to be widespread consensus. Move to Tentative Ready.
+
      
+
+
+
+
      Proposed resolution:
      
+
+
      Change 17.6.4.12 [value.error.codes] Value of error codes as indicated:
      
+
      
+ 
      Certain functions in the C++ standard library report errors via a 
+ std::error_code (19.4.2.2) object. That object's category() member shall 
+ return a reference to std::system_category() for errors originating from the 
+ operating system, or a reference to an implementation-defined error_category 
+ object for errors originating elsewhere. The implementation shall define the 
+ possible values of value() for each of these error categories. [Example: For 
+ operating systems that are based on POSIX, implementations are encouraged to 
+ define the std::system_category() values as identical to the POSIX errno values, 
+ with additional values as defined by the operating system's documentation. 
+ Implementations for operating systems that are not based on POSIX are 
+ encouraged to define values identical to the operating system's values. For 
+ errors that do not originate from the operating system, the implementation may 
+ provide enums for the associated values --end example]
      
+
      
+
+
      
+Change 19.5.1.1 [syserr.errcat.overview] Class error_category overview
+error_category synopsis as indicated:
+
      
+
+
      
+
      const error_category& get_generic_category();
+const error_category& get_system_category();
+
+static storage-class-specifier const error_category& generic_category = get_generic_category();
+static storage-class-specifier const error_category& system_category = get_system_category();
+
      
+
      
+
+
      
+Change 19.5.1.5 [syserr.errcat.objects] Error category objects as indicated:
+
      
+
+
      
+
      const error_category& get_generic_category();
+
      
+
+
      
+
+
      
+Returns: A reference to an object of a type derived from class error_category.
+
      
+
+
      
+Remarks: The object's default_error_condition and equivalent virtual
+functions shall behave as specified for the class error_category. The
+object's name virtual function shall return a pointer to the string
+"GENERIC".
+
      
+
      
+
+
      const error_category& get_system_category();
+
      
+
+
      
+
      
+Returns: A reference to an object of a type derived from class error_category.
+
      
+
+
      
+Remarks: The object's equivalent virtual functions shall behave as
+specified for class error_category. The object's name virtual function
+shall return a pointer to the string "system". The object's
+default_error_condition virtual function shall behave as follows:
+
      
+
      
+If the argument ev corresponds to a POSIX errno value posv, the function
+shall return error_condition(posv, generic_category()). Otherwise, the
+function shall return error_condition(ev, system_category()). What
+constitutes correspondence for any given operating system is
+unspecified. [Note: The number of potential system error codes is large
+and unbounded, and some may not correspond to any POSIX errno value.
+Thus implementations are given latitude in determining correspondence.
+-- end note]
+
      
+
      
+
+
      
+
+
      Change 19.5.2.3 [syserr.errcode.constructors] Class error_code constructors 
+as indicated:
      
+
      
+ 
      error_code();
      
+ 
      
+ 
      Effects: Constructs an object of type error_code.
      
+ 
      Postconditions: val_ == 0 and cat_ == &system_category().
      
+ 
      
+
      
+
      Change 19.5.2.4 [syserr.errcode.modifiers] Class error_code modifiers as 
+indicated:
      
+
      
+ 
      void clear();
      
+ 
      
+ 
      Postconditions: value() == 0 and category() == 
+ system_category().
      
+ 
      
+
      
+
      Change 19.5.2.6 [syserr.errcode.nonmembers] Class error_code non-member 
+functions as indicated:
      
+
      
+ 
      error_code make_error_code(errc e);
      
+ 
      
+ 
      Returns: error_code(static_cast<int>(e), generic_category()).
      
+ 
      
+
      
+
      Change 19.5.3.3 [syserr.errcondition.constructors] Class error_condition 
+constructors as indicated:
      
+
      
+ 
      error_condition();
      
+ 
      
+ 
      Effects: Constructs an object of type error_condition.
      
+ 
      Postconditions: val_ == 0 and cat_ == &generic_category().
      
+ 
      
+
      
+
      Change 19.5.3.4 [syserr.errcondition.modifiers] Class error_condition 
+modifiers as indicated:
      
+
      
+ 
      void clear();
      
+ 
      
+ 
      Postconditions: value() == 0 and category() == 
+ generic_category().
      
+ 
      
+
      
+
      Change 19.5.3.6 [syserr.errcondition.nonmembers] Class error_condition 
+non-member functions as indicated:
      
+
      
+ 
      error_condition make_error_condition(errc e);
      
+ 
      
+ 
      Returns: error_condition(static_cast<int>(e), generic_category()).
      
+ 
      
+
      
+ 
      Change 27.5 [iostreams.base] Iostreams base classes, Header <ios> 
+ synopsis as indicated:
      
+
      
+ 
      concept_map ErrorCodeEnum<io_errc> { };
+error_code make_error_code(io_errc e);
+error_condition make_error_condition(io_errc e);
+storage-class-specifier const error_category& iostream_category();
      
+
      
+
      Change 27.5.2.1.1 [ios::failure] Class ios_base::failure, paragraph 2 as 
+indicated:
      
+
      
+
      When throwing ios_base::failure exceptions, implementations should provide 
+values of ec that identify the specific reason for the failure. [ Note: Errors 
+arising from the operating system would typically be reported as 
+system_category() errors with an error value of the 
+error number reported by the operating system. Errors arising from within the 
+stream library would typically be reported as error_code(io_errc::stream, 
+iostream_category()). --end note ]
      
+
      
+
      Change 27.5.5.5 [error.reporting] Error reporting as indicated:
      
+
      
+ 
      error_code make_error_code(io_errc e);
      
+ 
      
+ 
      Returns: error_code(static_cast<int>(e), iostream_category()).
      
+ 
      
+ 
      error_condition make_error_condition(io_errc e);
      
+ 
      
+ 
      Returns: error_condition(static_cast<int>(e), 
+ iostream_category()).
      
+ 
      
+ 
      storage-class-specifier const error_category& iostream_category();
      
+ 
      
+ 
      The implementation shall initialize iostream_category. Its storage-class-specifier 
+ may be static or extern. It is unspecified whether initialization is static 
+ or dynamic (3.6.2). If initialization is dynamic, it shall occur before 
+ completion of the dynamic initialization of the first translation unit 
+ dynamically initialized that includes header <system_error>.
      
+
      
+Returns: A reference to an object of a type derived from class error_category.
+
      
+
      Remarks: The object's default_error_condition and equivalent virtual functions shall 
+behave as specified for the class error_category. The object's name virtual 
+function shall return a pointer to the string "iostream".
      
+ 
      
+
      
+
+
+
+
+
+
+
+
      
 
      894. longjmp and destructors
      
 
      Section: 18.10 [support.runtime] Status: WP
  Submitter: Lawrence Crowl, Alisdair Meredith Opened: 2008-09-17  Last modified: 2009-03-09
      
@@ -35467,4 +36502,3499 @@ any automatic objects.
 
 
 
+
      
+
      898. Small contradiction in n2723 to forward to committee
      
+
      Section: 23.3.3.5 [forwardlist.ops] Status: WP
+ Submitter: Arch Robison Opened: 2008-09-08  Last modified: 2009-07-18
      
+
      View other active issues in [forwardlist.ops].
      
+
      View all other issues in [forwardlist.ops].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+I ran across a small contradiction in working draft n2723. 
+
      
+
      
+
      
+23.3.3 [forwardlist]p2: A forward_list satisfies all of the
+requirements of a container (table 90), except that the size() member
+function is not provided.
+
      
+
      
+23.3.3.5 [forwardlist.ops]p57: Complexity: At most size() + x.size() - 1
+comparisons.
+
      
+
      
+
      
+Presumably 23.3.3.5 [forwardlist.ops]p57 needs to be rephrased to not use
+size(), or note that it is used there only for sake of notational convenience. 
+
      
+
+
      [
+2009-03-29 Beman provided proposed wording.
+]
      
+
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+We agree with the proposed resolution.
+
      
+
      
+Move to Tentatively Ready.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      Change 23.3.3.5 [forwardlist.ops],
+forward_list operations, paragraph 19, merge complexity as indicated:
+
      
+
      Complexity: At most size() + x.size()
+distance(begin(), end()) + distance(x.begin(), x.end()) - 1
+comparisons.
+
      
+
+
+
+
+
+
      
+
      899. Adjusting shared_ptr for nullptr_t
      
+
      Section: 20.8.10.2.2 [util.smartptr.shared.dest] Status: WP
+ Submitter: Peter Dimov Opened: 2008-09-18  Last modified: 2009-07-18
      
+
      View all other issues in [util.smartptr.shared.dest].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+James Dennett, message c++std-lib-22442:
+
      
+
      
+The wording below addresses one case of this, but opening an
+issue to address the need to sanity check uses of the term "pointer"
+in 20.8.10.2 [util.smartptr.shared] would be a good thing.
+
      
+
      
+There's one more reference, in ~shared_ptr; we can apply your suggested change to it, too. That is:
+
      
+
      
+Change 20.8.10.2.2 [util.smartptr.shared.dest]/1 second bullet from:
+
      
+
      
+Otherwise, if *this owns a pointer p and a deleter d, d(p) is called.
+
      
+
      
+to:
+
      
+
      
+Otherwise, if *this owns an object p and a deleter d, d(p) is called.
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+Recommend Review.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+Peter Dimov notes the analogous change has already been made
+to "the new nullptr_t taking constructors
+in 20.8.10.2.1 [util.smartptr.shared.const] p9-13."
+
      
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 20.8.10.2.2 [util.smartptr.shared.dest]/1 second bullet:
+
      
+
      
+
        
+
      • ...
        • 
+
      • 
+Otherwise, if *this owns a pointer
+an object p and a
+deleter d, d(p) is called.
+
        • 
+
      
+
      
+
+
+
+
+
+
      
+
      904. result_of argument types
      
+
      Section: 20.7.4 [func.ret] Status: WP
+ Submitter: Jonathan Wakely Opened: 2008-09-10  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+The WP and TR1 have the same text regarding the argument types of a
+result_of expression:
+
      
+
      
+The values ti are lvalues when the corresponding type Ti is a
+reference type, and rvalues otherwise.
+
      
+
      
+I read this to mean that this compiles:
+
      
+
      typedef int (*func)(int&);
+result_of<func(int&&)>::type i = 0;
+
      
+
      
+even though this doesn't:
+
      
+
      int f(int&);
+f( std::move(0) );
+
      
+
      
+Should the text be updated to say "when Ti is an lvalue-reference
+type" or am I missing something?
+
      
+
      
+I later came up with this self-contained example which won't compile,
+but I think it should:
+
      
+
      struct X {
+  void operator()(int&);
+  int operator()(int&&);
+} x;
+
+std::result_of< X(int&&) >::type i = x(std::move(0));
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+Recommend Tentatively Ready.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change 20.7.4 [func.ret], p1:
+
      
+
+
      
+... The values ti are lvalues 
+when the corresponding type Ti is an lvalue-reference type,
+and rvalues otherwise. 
+
      
+
+
+
+
+
+
      
+
      907. Bitset's immutable element retrieval is inconsistently defined
      
+
      Section: 20.3.6.2 [bitset.members] Status: WP
+ Submitter: Daniel Krügler Opened: 2008-09-26  Last modified: 2009-07-18
      
+
      View all other issues in [bitset.members].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+The current standard 14882::2003(E) as well as the current draft
+N2723
+have in common a contradiction of the operational semantics
+of member function test 20.3.6.2 [bitset.members]/56-58 and the immutable
+member operator[] overload 20.3.6.2 [bitset.members]/64-66 (all references
+are defined in terms of
+N2723):
+
      
+
+
        
+
      1. bool test(size_t pos) const;
+
        
+
        
+
        
+Requires: pos is valid
+
        
+
        
+Throws: out_of_range if pos does not correspond
+to a valid bit position.
+
        
+
        
+Returns: true if the bit at position pos in *this
+has the value one.
+
        
+
        
+
        2. 
+
      2. constexpr bool operator[](size_t pos) const;
+
        
+
        
+
        
+Requires: pos shall be valid.
+
        
+
        
+Throws: nothing.
+
        
+
        
+Returns: test(pos).
+
        
+
        
+
        3. 
+
      
+
+
      
+Three interpretations:
+
      
+
+
        
+
      1. 
+The operator[] overload is indeed allowed to throw an exception
+(via test(), if pos corresponds to an invalid bit position) which does
+not leave the call frame. In this case this function cannot be a
+constexpr function, because test() is not, due to
+5.19 [expr.const]/2, last bullet.
+
        2. 
+
      2. 
+The intend was not to throw an exception in test in case of an
+invalid bit position. There is only little evidence for this interpretation.
+
        3. 
+
      3. 
+The intend was that operator[] should not throw any exception,
+but that test has the contract to do so, if the provided bit position
+is invalid.
+
        4. 
+
      
+
+
      
+The problem became worse, because issue 720
+recently voted into WP argued that member test logically must be
+a constexpr function, because it was used to define the semantics
+of another constexpr function (the operator[] overload).
+
      
+
+
      
+Three alternatives are proposed, corresponding to the three bullets
+(A), (B), and (C), the author suggests to follow proposal (C).
+
      
+
+
+Proposed alternatives:
+
+
+
        
+
      1. 
+
        
+Remove the constexpr specifier in front of operator[] overload and
+undo that of member test (assuming 720 is accepted) in both the
+class declaration 20.3.6 [template.bitset]/1 and in the member description
+before 20.3.6.2 [bitset.members]/56 and before /64 to read:
+
        
+
        constexpr bool test(size_t pos) const;
+..
+constexpr bool operator[](size_t pos) const;
+
        
+
+
        
+Change the throws clause of p. 65 to read:
+
        
+
+
        
+Throws: nothing
+out_of_range if pos does not correspond to a valid bit
+position.
+
        
+
        2. 
+
      2. 
+
        
+Replace the throws clause p. 57 to read:
+
        
+
+
        
+Throws: out_of_range if pos does not correspond to a valid bit
+position nothing.
+
        
+
        3. 
+
      3. 
+
        
+Undo the addition of the constexpr specifier to the test member
+function in both class declaration 20.3.6 [template.bitset]/1 and in the
+member description before 20.3.6.2 [bitset.members]/56, assuming that 720
+was applied.
+
        
+
+
        constexpr bool test(size_t pos) const;
+
        
+
+
        
+Change the returns clause p. 66 to read:
+
        
+
+
        
+Returns: test(pos) true if the bit at position pos in *this
+has the value one, otherwise false.
+
        
+
        4. 
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+
      
+Lawrence: proposed resolutions A, B, C are mutually exclusive.
+
      
+
      
+Recommend Review with option C.
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
+
        
+
      1. 
+
        
+Undo the addition of the constexpr specifier to the test member
+function in both class declaration 20.3.6 [template.bitset]/1 and in the
+member description before 20.3.6.2 [bitset.members]/56, assuming that 720
+was applied.
+
        
+
+
        constexpr bool test(size_t pos) const;
+
        
+
+
        
+Change the returns clause p. 66 to read:
+
        
+
+
        
+Returns: test(pos) true if the bit at position pos in *this
+has the value one, otherwise false.
+
        
+
        2. 
+
      
+
+
+
+
+
+
+
      
+
      909. regex_token_iterator should use initializer_list
      
+
      Section: 28.12.2 [re.tokiter] Status: WP
+ Submitter: Daniel Krügler Opened: 2008-09-26  Last modified: 2009-07-18
      
+
      View all other issues in [re.tokiter].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses UK 319
      
+
      
+Construction of a regex_token_iterator (28.12.2 [re.tokiter]/6+) usually
+requires the provision of a sequence of integer values, which
+can currently be done via a std::vector<int> or
+a C array of int. Since the introduction of initializer_list in the
+standard it seems much more reasonable to provide a
+corresponding constructor that accepts an initializer_list<int>
+instead. This could be done as a pure addition or one could
+even consider replacement. The author suggests the
+replacement strategy (A), but provides an alternative additive
+proposal (B) as a fall-back, because of the handiness of this
+range type:
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We strongly recommend alternative B of the proposed resolution
+in order that existing code not be broken.
+With that understanding, move to Tentatively Ready.
+
      
+
+
      Original proposed wording:
      
+
+
        
+

      1. 
+
          
+
        1. 
+
          
+In 28.12.2 [re.tokiter]/6 and the list 28.12.2.1 [re.tokiter.cnstr]/10-11 change the
+constructor declaration:
+
          
+
+
          template <std::size_t N>
+regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
+                     const regex_type& re,
+                     const int (&submatches)[N] initializer_list<int> submatches,
+                     regex_constants::match_flag_type m =
+                       regex_constants::match_default);
+
          
+
          2. 
+
+
        2. 
+
          
+In 28.12.2.1 [re.tokiter.cnstr]/12 change the last sentence
+
          
+
+
          
+The third constructor initializes the member subs to hold
+a copy of the sequence of integer values pointed to by the
+iterator range [&submatches.begin(),
+&submatches.end() + N).
+
          
+
          3. 
+
        
+
        2. 
+
+

      2. 
+
          
+
        1. 
+
          
+In 28.12.2 [re.tokiter]/6 and the list 28.12.2.1 [re.tokiter.cnstr]/10-11 insert the
+following constructor declaration between the already existing ones
+accepting a std::vector and a C array of int, resp.:
+
          
+
+
          regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
+                     const regex_type& re,
+                     initializer_list<int> submatches,
+                     regex_constants::match_flag_type m =
+                       regex_constants::match_default);
+
          
+
          2. 
+
        2. 
+
          
+In 28.12.2.1 [re.tokiter.cnstr]/12 change the last sentence
+
          
+
+
          
+The third and fourth constructor initializes the member subs
+to hold a copy of the sequence of integer values pointed to
+by the iterator range [&submatches,&submatches + N)
+and [submatches.begin(),submatches.end()), respectively.
+
          
+
          3. 
+
        
+
        3. 
+
+
      
+
+
+
+
      Proposed resolution:
      
+
+
        
+
+

      1. 
+
          
+
        1. 
+
          
+In 28.12.2 [re.tokiter]/6 and the list 28.12.2.1 [re.tokiter.cnstr]/10-11 insert the
+following constructor declaration between the already existing ones
+accepting a std::vector and a C array of int, resp.:
+
          
+
+
          regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
+                     const regex_type& re,
+                     initializer_list<int> submatches,
+                     regex_constants::match_flag_type m =
+                       regex_constants::match_default);
+
          
+
          2. 
+
        2. 
+
          
+In 28.12.2.1 [re.tokiter.cnstr]/12 change the last sentence
+
          
+
+
          
+The third and fourth constructor initializes the member subs
+to hold a copy of the sequence of integer values pointed to
+by the iterator range [&submatches,&submatches + N)
+and [submatches.begin(),submatches.end()), respectively.
+
          
+
          3. 
+
        
+
        2. 
+
+
      
+
+
+
+
+
+
+
      
+
      922. [func.bind.place] Number of placeholders
      
+
      Section: B [implimits] Status: WP
+ Submitter: Sohail Somani Opened: 2008-10-11  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      Addresses DE 24
      
+
+
      
+With respect to the section 20.7.12.1.4 [func.bind.place]:
+
      
+
      
+TR1 dropped some suggested implementation quantities for the number of
+placeholders. The purpose of this defect is to put these back for C++0x.
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+
      
+see DE 24
+
      
+
      
+Recommend applying the proposed resolution from DE 24, with that
+Tentatively Ready.
+
      
+
      
+
+Original proposed resolution:
+
+
      
+Add 20.7.12.1.4 [func.bind.place]/2:
+
      
+
+
      
+While the exact number of placeholders (_M) is implementation defined,
+this number shall be at least 10.
+
      
+
+
+
+
      Proposed resolution:
      
+
+
      
+Add to B [implimits]:
+
      
+
+
        
+
      • 
+Number of placeholders (20.7.12.1.4 [func.bind.place]) [10].
+
        • 
+
      
+
+
+
+
+
+
+
      
+
      925. shared_ptr's explicit conversion from unique_ptr
      
+
      Section: 20.8.10.2.1 [util.smartptr.shared.const] Status: WP
+ Submitter: Rodolfo Lima Opened: 2008-10-12  Last modified: 2009-07-18
      
+
      View other active issues in [util.smartptr.shared.const].
      
+
      View all other issues in [util.smartptr.shared.const].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+The current working draft
+(N2798),
+section 20.8.10.2.1 [util.smartptr.shared.const] declares
+shared_ptr's constructor that takes a rvalue reference to unique_ptr and
+auto_ptr as being explicit, affecting several valid smart pointer use
+cases that would take advantage of this conversion being implicit, for
+example:
+
      
+
+
      class A;
+std::unique_ptr<A> create();
+void process(std::shared_ptr<A> obj);
+
+int main()
+{
+   process(create());                  // use case #1
+   std::unique_ptr<A> uobj = create();
+   process(std::move(uobj));           // use case #2
+   return 0;
+}
+
      
+
+
      
+If unique_ptr to shared_ptr conversions are explicit, the above lines
+should be written:
+
      
+
+
      process(std::shared_ptr<A>(create()));        // use case #1
+process(std::shared_ptr<A>(std::move(uobj))); // use case #2
+
      
+
+
      
+The extra cast required doesn't seems to give any benefits to the user,
+nor protects him of any unintended conversions, this being the raison
+d'etre of explicit constructors.
+
      
+
+
      
+It seems that this constructor was made explicit to mimic the conversion
+from auto_ptr in pre-rvalue reference days, which accepts both lvalue and
+rvalue references. Although this decision was valid back then, C++0x
+allows the user to express in a clear and non verbose manner when he wants
+move semantics to be employed, be it implicitly (use case 1) or explicitly
+(use case 2).
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+Howard and Alisdair like the motivating use cases
+and the proposed resolution.
+
      
+
      
+Move to Tentatively Ready.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+In both 20.8.10.2 [util.smartptr.shared] paragraph 1 and 
+20.8.10.2.1 [util.smartptr.shared.const] change:
+
      
+
+
      template <class Y> explicit shared_ptr(auto_ptr<Y> &&r);
+template <class Y, class D> explicit shared_ptr(unique_ptr<Y, D> &&r);
+
      
+
+
+
+
+
+
+
      
+
      931. type trait extent<T, I>
      
+
      Section: 20.6.4.3 [meta.unary.prop] Status: WP
+ Submitter: Yechezkel Mett Opened: 2008-11-04  Last modified: 2009-07-18
      
+
      View other active issues in [meta.unary.prop].
      
+
      View all other issues in [meta.unary.prop].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+The draft (N2798) says in 20.6.4.3 [meta.unary.prop] Table 44: 
+
      
+
      
+
+
+
+
+
+
+
+
      Table 44 -- Type property queries
      TemplateValue
      
+template <class T, unsigned I = 0> struct extent;
+
+If T is not an array type (8.3.4), or if it has rank less than
+I, or if I is 0
+and T has type "array of unknown bound of U", then 0; otherwise, the
+size of the I'th dimension of T
+
      
+
      
+
+
      
+Firstly it isn't clear from the wording if I is 0-based or 1-based 
+("the I'th dimension" sort of implies 1-based). From the following 
+example it is clear that the intent is 0-based, in which case it 
+should say "or if it has rank less than or equal to I".
+
      
+
      
+Sanity check:
+
      
+
      
+The example says assert((extent<int[2], 1>::value) == 0);
+
      
+
      
+Here the rank is 1 and I is 1, but the desired result is 0.
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+
      
+Do not use "size" or "value", use "bound". Also, move the
+cross-reference to 8.3.4 to just after "bound".
+
      
+
      
+Recommend Tentatively Ready.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+In Table 44 of 20.6.4.3 [meta.unary.prop], third row, column "Value",
+change the cell content:
+
      
+
+
      
+
+
+
+
+
+
+
+
      Table 44 -- Type property queries
      TemplateValue
      
+template <class T, unsigned I = 0> struct extent;
+
+If T is not an array type (8.3.4), or if it has rank less than
+ or equal to I, or if I is 0
+and T has type "array of unknown bound of U", then 0; otherwise, the
+size bound (8.3.4) of the I'th dimension of T,
+where indexing of I is zero-based.
+
      
+
      
+
+
      [
+Wording supplied by Daniel.
+]
      
+
+
+
+
+
+
+
+
      
+
      938. default_delete<T[]>::operator() should only accept T*
      
+
      Section: 20.8.9.1.2 [unique.ptr.dltr.dflt1] Status: WP
+ Submitter: Howard Hinnant Opened: 2008-12-07  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+Consider:
+
      
+
+
      derived* p = new derived[3];
+std::default_delete<base[]> d;
+d(p);  // should fail
+
      
+
+
      
+Currently the marked line is a run time failure.  We can make it a compile
+time failure by "poisoning" op(U*).
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+Recommend Review.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Add to 20.8.9.1.2 [unique.ptr.dltr.dflt1]:
+
      
+
+
      namespace std {
+  template <class T> struct default_delete<T[]> {
+    void operator()(T*) const;
+  template <class U> void operator()(U*) const = delete;
+};
+}
+
      
+
+
+
+
+
+
      
+
      943. ssize_t undefined
      
+
      Section: 29.5.2 [atomics.types.address] Status: WP
+ Submitter: Holger Grund Opened: 2008-12-19  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+There is a row in "Table 122 - Atomics for standard typedef types"
+in 29.5.1 [atomics.types.integral] with atomic_ssize_t
+and ssize_t. Unless, I'm missing something ssize_t
+is not defined by the standard.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Move to review. Proposed resolution: Remove the typedef. Note: ssize_t
+is a POSIX type.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Remove the row containing ssize_t from Table 119
+"Atomics for standard typedef types" in 29.5.2 [atomics.types.address].
+
      
+
+
+
+
+
+
      
+
      948. ratio arithmetic tweak
      
+
      Section: 20.4.2 [ratio.arithmetic] Status: WP
+ Submitter: Howard Hinnant Opened: 2008-12-26  Last modified: 2009-07-18
      
+
      View all other issues in [ratio.arithmetic].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+N2800,
+20.4.2 [ratio.arithmetic] lacks a paragraph from the proposal
+N2661:
+
      
+
+
      
+
      ratio arithmetic [ratio.arithmetic]
      
+
+
      
+... If the implementation is unable to form the indicated ratio due to
+overflow, a diagnostic shall be issued.
+
      
+
      
+
+
      
+The lack of a diagnostic on compile-time overflow is a significant lack of
+functionality.  This paragraph could be put back into the WP simply editorially.
+However in forming this issue I realized that we can do better than that.  This
+paragraph should also allow alternative formulations which go to extra lengths
+to avoid overflow when possible.  I.e. we should not mandate overflow when the
+implementation can avoid it.
+
      
+
+
      
+For example:
+
      
+
+
      
+
      template <class R1, class R2> struct ratio_multiply {
+  typedef see below} type; 
+
      
+
+
      
+The nested typedef type shall be a synonym for ratio<T1, T2> where
+T1 has the value R1::num * R2::num and T2 has the
+value R1::den * R2::den.
+
      
+
+
      
+
+
      
+Consider the case where intmax_t is a 64 bit 2's complement signed integer,
+and we have:
+
      
+
+
      typedef std::ratio<0x7FFFFFFFFFFFFFFF, 0x7FFFFFFFFFFFFFF0> R1;
+typedef std::ratio<8, 7> R2;
+typedef std::ratio_multiply<R1, R2>::type RT;
+
      
+
+
      
+According to the present formulation the implementaiton will multiply
+0x7FFFFFFFFFFFFFFF * 8 which will result in an overflow and subsequently
+require a diagnostic.
+
      
+
+
      
+However if the implementation is first allowed to divde 0x7FFFFFFFFFFFFFFF
+by 7 obtaining 0x1249249249249249 / 1 and divide
+8 by 0x7FFFFFFFFFFFFFF0 obtaining 1 / 0x0FFFFFFFFFFFFFFE,
+then the exact result can then be computed without overflow:
+
      
+
+
      [0x7FFFFFFFFFFFFFFF/0x7FFFFFFFFFFFFFF0] * [8/7] = [0x1249249249249249/0x0FFFFFFFFFFFFFFE]
+
      
+
+
      
+Example implmentation which accomplishes this:
+
      
+
+
      template <class R1, class R2>
+struct ratio_multiply
+{
+private:
+    typedef ratio<R1::num, R2::den> _R3;
+    typedef ratio<R2::num, R1::den> _R4;
+public:
+    typedef ratio<__ll_mul<_R3::num, _R4::num>::value,
+                  __ll_mul<_R3::den, _R4::den>::value> type;
+};
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+Recommend Tentatively Ready.
+
      
+
+
+
+
+
      Proposed resolution:
      
+
      
+Add a paragraph prior to p1 in 20.4.2 [ratio.arithmetic]:
+
      
+
+
      
+Implementations may use other algorithms to compute the indicated ratios to avoid overflow. 
+If overflow occurs, a diagnostic shall be issued.
+
      
+
+
+
+
+
+
      
+
      949. owner_less
      
+
      Section: 20.8.10.4 [util.smartptr.ownerless] Status: WP
+ Submitter: Thomas Plum Opened: 2008-12-30  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+20.8.10.4 [util.smartptr.ownerless] (class template owner_less) says that 
+operator()(x,y) shall return x.before(y).
+
      
+
      
+However, shared_ptr and weak_ptr have an owner_before() but not a
+before(), and there's no base class to provide a missing before().
+
      
+
      
+Being that the class is named  owner_less , I'm guessing that
+"before()" should be "owner_before()", right?
+
      
+
+
      [
+Herve adds:
+]
      
+
+
+
      
+Agreed with the typo, it should be "shall return x.owner_before(y)".
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+Recommend Tentatively Ready.
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change 20.8.10.4 [util.smartptr.ownerless] p2:
+
      
+
+
      
+-2- operator()(x,y) shall return
+x.owner_before(y). [Note: ...
+
      
+
+
+
+
+
+
      
+
      965. Various threading bugs #15
      
+
      Section: 30.5.1 [thread.condition.condvar] Status: WP
+ Submitter: Pete Becker Opened: 2009-01-07  Last modified: 2009-07-18
      
+
      View other active issues in [thread.condition.condvar].
      
+
      View all other issues in [thread.condition.condvar].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+30.5.1 [thread.condition.condvar]: the constructor for
+condition_variable throws an exception with error code
+device_or_resource_busy "if attempting to initialize a
+previously-initialized but as of yet undestroyed condition_variable."
+How can this occur?
+
      
+
+
      [
+Summit:
+]
      
+
+
      
+
      
+Move to review. Proposed resolution: strike the device_or_resource_busy
+error condition from the constructor of condition_variable.
+
      
+
        
+
      • 
+This is a POSIX error that cannot occur in this interface because the
+C++ interface does not separate declaration from initialization.
+
        • 
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 30.5.1 [thread.condition.condvar] p3:
+
      
+
+
      
+
        
+
      • ...
        • 
+
      • 
+device_or_resource_busy -- if attempting to initialize a
+previously-initialized but as of yet undestroyed
+condition_variable.
+
        • 
+
      
+
      
+
+
+
+
+
+
      
+
      970. addressof overload unneeded
      
+
      Section: 20.8.8.1 [object.addressof] Status: WP
+ Submitter: Howard Hinnant Opened: 2009-01-16  Last modified: 2009-07-18
      
+
      View all other issues in [object.addressof].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+20.8.8.1 [object.addressof] specifies:
+
      
+
+
      template <ObjectType T> T* addressof(T& r);
+template <ObjectType T> T* addressof(T&& r);
+
      
+
+
      
+The two signatures are ambiguous when the argument is an lvalue.  The
+second signature seems not useful:  what does it mean to take the
+address of an rvalue?
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+Recommend Review.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 20.8.8.1 [object.addressof]:
+
      
+
+
      template <ObjectType T> T* addressof(T& r);
+template <ObjectType T> T* addressof(T&& r);
+
      
+
+
+
+
+
+
+
      
+
      975. is_convertible cannot be instantiated for  non-convertible types
      
+
      Section: 20.6.5 [meta.rel] Status: WP
+ Submitter: Daniel Krügler Opened: 2009-01-25  Last modified: 2009-07-18
      
+
      View all other issues in [meta.rel].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+Addresses UK 206
+
+
      
+Related to 1114.
+
      
+
+
      
+The current specification of std::is_convertible (reference is draft
+N2798)
+is basically defined by 20.6.5 [meta.rel]/4:
+
      
+
+
      
+
      
+In order to instantiate the template is_convertible<From,
+To>, the following code shall be well formed:
+
      
+
+
      template <class T>
+  typename add_rvalue_reference<T>::type create();
+
+To test() {
+  return create<From>();
+}
+
      
+
+
      
+[Note: This requirement gives well defined results for reference
+types, void types, array types, and function types. --end note]
+
      
+
      
+
+
      
+The first sentence can be interpreted, that e.g. the expression
+
      
+
+
      std::is_convertible<double, int*>::value
+
      
+
+
      
+is ill-formed because std::is_convertible<double, int*> could not be
+instantiated, or in more general terms: The wording requires that
+std::is_convertible<X, Y> cannot be instantiated for otherwise valid
+argument types X and Y if X is not convertible to Y.
+
      
+
+
      
+This semantic is both unpractical and in contradiction to what the last type
+traits paper
+N2255
+proposed:
+
      
+
+
      
+
      
+If the following test function is well formed code b
+is true, else it is false.
+
      
+
+
      template <class T>
+  typename add_rvalue_reference<T>::type create();
+
+To test() {
+  return create<From>();
+}
+
      
+
+
      
+[Note: This definition gives well defined results for reference
+types, void types, array types, and function types. --end note]
+
      
+
      
+
+
      [
+Post Summit:
+]
      
+
+
+
      
+
      
+Jens: Checking that code is well-formed and then returning true/false
+sounds like speculative compilation. John Spicer would really dislike
+this. Please find another wording suggesting speculative compilation.
+
      
+
      
+Recommend Open.
+
      
+
      
+
+
      [
+Post Summit, Howard adds:
+]
      
+
+
+
      
+
      
+John finds the following wording clearer:
+
      
+
      
+
+
+
+
+
+
+
+
+
+
+
      TemplateConditionComments
      template <class From, class To>
      struct is_convertible;      		see belowFrom and To shall be complete types, arrays of unknown bound,
+or (possibly cv-qualified) void types.
      
+
+
      
+Given the following function prototype:
+
      
+
+
      template <class T>
+  typename add_rvalue_reference<T>::type create();
+
      
+
+
      
+is_convertible<From, To>::value shall be true if the
+return expression in the following code would be well-formed, including
+any implicit conversions to the return type of the function, else
+is_convertible<From, To>::value shall be false.
+
      
+
+
      To test() {
+  return create<From>();
+}
+
      
+
+
      
+
+
      
+
+Original proposed wording:
+
+
      
+In 20.6.5 [meta.rel]/4 change:
+
      
+
+
      
+In order to instantiate the template is_convertible<From, To>, the
+following code shall be well formed If the following code
+is well formed is_convertible<From, To>::value is true, otherwise
+false:[..]
+
      
+
+
      Revision 2
      
+
+
      
+
+
      
+In 20.6.5 [meta.rel] change:
+
      
+
+
      
+
+
+
+
+
+
+
+
+
+
+
+
      TemplateConditionComments
      .........
      template <class From, class To>
      struct is_convertible;      		
+The code set out below shall be well formed.
+see belowFrom and To shall be complete types, arrays of unknown bound,
+or (possibly cv-qualified) void types.
      
+
+
      
+-4- In order to instantiate the template is_convertible<From, To>, the
+following code shall be well formed:
+Given the following function prototype:
+
      
+
+
      template <class T> 
+  typename add_rvalue_reference<T>::type create();
+
      
+
+
      
+is_convertible<From, To>::value inherits either directly or
+indirectly from true_type if the
+return expression in the following code would be well-formed, including
+any implicit conversions to the return type of the function, else
+is_convertible<From, To>::value inherits either directly or
+indirectly from false_type.
+
      
+
+
      To test() { 
+  return create<From>(); 
+}
+
      
+
+
      
+[Note: This requirement gives well defined results for reference types,
+void types, array types, and function types. -- end note]
+
      
+
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
+
      
+In 20.6.5 [meta.rel] change:
+
      
+
+
      
+
+
+
+
+
+
+
+
+
+
+
+
      TemplateConditionComments
      .........
      template <class From, class To>
      struct is_convertible;      		
+The code set out below shall be well formed.
+see belowFrom and To shall be complete types, arrays of unknown bound,
+or (possibly cv-qualified) void types.
      
+
+
      
+-4- In order to instantiate the template is_convertible<From, To>, the
+following code shall be well formed:
+Given the following function prototype:
+
      
+
+
      template <class T> 
+  typename add_rvalue_reference<T>::type create();
+
      
+
+
      
+the predicate condition for a template specialization
+is_convertible<From, To> shall be satisfied, if and only
+if the return expression in the following code would be well-formed,
+including any implicit conversions to the return type of the
+function.
+
      
+
+
      To test() { 
+  return create<From>(); 
+}
+
      
+
+
      
+[Note: This requirement gives well defined results for reference types,
+void types, array types, and function types. — end note]
+
      
+
+
      
+
+
+
+
+
+
      
+
      981. Unordered container requirements should add  initializer_list support
      
+
      Section: 23.2.5 [unord.req] Status: WP
+ Submitter: Daniel Krügler Opened: 2009-02-08  Last modified: 2009-07-18
      
+
      View other active issues in [unord.req].
      
+
      View all other issues in [unord.req].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+Refering to
+N2800
+all container requirements tables (including those for
+associative containers) provide useful member function overloads
+accepting std::initializer_list as argument, the only exception is
+Table 87. There seems to be no reason for not providing them, because 23.5 [unord]
+is already initializer_list-aware. For the sake of 
+library interface consistency and user-expectations corresponding 
+overloads should be added to the table requirements of unordered 
+containers as well.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+We agree with the proposed resolution.
+
      
+
      
+Move to Tentatively Ready.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
+
      
+In 23.2.5 [unord.req]/9 insert:
+
      
+
+
      
+... [q1, q2) is a valid range in a, il
+designates an object of type initializer_list<value_type>, t is a value of type
+X::value_type, ...
+
      
+
+
      
+In 23.2.5 [unord.req], Table 87 insert:
+
      
+
+
      
+
+
+
+
+
+
+
+
+
+ 
+ 
+
+
+
+
+
+
+
+
+
+ 
+ 
+
+
+
+
+
+
+
+
+
+ 
+ 
+
+
+
      Table 87 - Unordered associative container requirements (in addition to container)
      Expression Return type Assertion/note
      pre-/post-condition      		 Complexity
      X(i, j)
      X a(i, j)      		 X ... ...
      X(il) XSame as X(il.begin(), il.end()).Same as X(il.begin(), il.end()).
      ... ... ... ...
      a = b X ... ...
      a = il X&a = X(il); return *this;Same as a = X(il).
      ... ... ... ...
      a.insert(i, j) void ... ...
      a.insert(il) voidSame as a.insert(il.begin(), il.end()).Same as a.insert(il.begin(), il.end()).
      
+
      
+
+
+
+
+
+
+
      
+
      982. Wrong complexity for initializer_list assignment in  Table 85
      
+
      Section: 23.2.4 [associative.reqmts] Status: WP
+ Submitter: Daniel Krügler Opened: 2009-02-08  Last modified: 2009-07-18
      
+
      View all other issues in [associative.reqmts].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+According to
+N2800,
+the associative container requirements table 85 says
+    that assigning an initializer_list to such a container is of
+    constant complexity, which is obviously wrong.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+We agree with the proposed resolution.
+
      
+
      
+Move to Tentatively Ready.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
+
      
+In 23.2.4 [associative.reqmts], Table 85 change:
+
      
+
+
      
+
+
+
+
+
+
+ 
+
+
+
      Table 85 - Associative container requirements (in addition to container)
      Expression Return type Assertion/note
      pre-/post-condition      		 Complexity
      a = il X& a = X(il);
      return *this;      		constantSame as a = X(il).
      
+
      
+
+
+
+
+
+
+
      
+
      984. Does <cinttypes> have macro guards?
      
+
      Section: 27.9.2 [c.files] Status: WP
+ Submitter: Howard Hinnant Opened: 2009-02-12  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+The C standard says about <inttypes.h>:
+
      
+
+
      
+C++ implementations should define these macros only when __STDC_FORMAT_MACROSis defined 
+before <inttypes.h> is included.
+
      
+
+
      
+The C standard has a similar note about <stdint.h>.  For <cstdint>
+we adopted a "thanks but no thanks" policy and documented that fact in
+18.4.1 [cstdint.syn]:
+
      
+
+
      
+... [Note: The macros defined by <stdint> are
+provided unconditionally. In particular, the symbols
+__STDC_LIMIT_MACROS and __STDC_CONSTANT_MACROS
+(mentioned in C99 footnotes 219, 220, and 222) play no role in C++.
+-- end note]
+
      
+
+
      
+I recommend we put a similar note in 27.9.2 [c.files] regarding <cinttypes>.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Add to 27.9.2 [c.files]:
+
      
+
+
      
+Table 112 describes header <cinttypes>.
+
+[Note: The macros defined by <cintypes> are
+provided unconditionally. In particular, the symbol
+__STDC_FORMAT_MACROS
+(mentioned in C99 footnote 182) plays no role in C++.
+-- end note]
+
+
      
+
+
+
+
+
+
      
+
      986. Generic try_lock contradiction
      
+
      Section: 30.4.4 [thread.lock.algorithm] Status: WP
+ Submitter: Chris Fairles Opened: 2009-02-14  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+In 30.4.4 [thread.lock.algorithm], the generic try_lock effects (p2) say that a failed
+try_lock is when it either returns false or throws an exception. In
+the event a call to try_lock does fail, by either returning false or
+throwing an exception, it states that unlock shall be called for all
+prior arguments. Then the returns clause (p3) goes on to state
+in a note that after returning, either all locks are locked or none
+will be. So what happens if multiple locks fail on try_lock?
+
      
+
+
      
+Example:
+
      
+
+
      #include <mutex>
+
+int main() {
+ std::mutex m0, m1, m2;
+ std::unique_lock<std::mutex> l0(m0, std::defer_lock);
+ std::unique_lock<std::mutex> l1(m1); //throws on try_lock
+ std::unique_lock<std::mutex> l2(m2); //throws on try_lock
+
+ int result = std::try_lock(l0, l1, l2);
+
+ assert( !l0.owns_lock() );
+ assert( l1.owns_lock() ); //??
+ assert( l2.owns_lock() ); //??
+}
+
      
+
+
      
+The first lock's try_lock succeeded but, being a prior argument to a
+lock whose try_lock failed, it gets unlocked as per the effects clause
+of 30.4.4 [thread.lock.algorithm]. However, 2 locks remain locked in this case but the return
+clause states that either all arguments shall be locked or none will
+be. This seems to be a contradiction unless the intent is for
+implementations to make an effort to unlock not only prior arguments,
+but the one that failed and those that come after as well. Shouldn't
+the note only apply to the arguments that were successfully locked?
+
      
+
+
      
+Further discussion and possible resolutions in c++std-lib-23049.
+
      
+
+
      [
+Summit:
+]
      
+
+
      
+Move to review. Agree with proposed resolution.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
+
      
+Change 30.4.4 [thread.lock.algorithm], p2:
+
      
+
+
      
+-2- Effects: Calls try_lock() for each argument in order
+beginning with the first until all arguments have been processed or a
+call to try_lock() fails, either by returning false or by throwing an
+exception. If a call to try_lock() fails, unlock() shall be called for
+all prior arguments and there shall be no further calls to try_lock().
+
      
+
+
      
+Delete the note from 30.4.4 [thread.lock.algorithm], p3
+
      
+
+
      
+-3- Returns: -1 if all calls to try_lock() returned true,
+otherwise a 0-based index value that indicates 
+the argument for which try_lock() returned false. [Note:
+On return, either all arguments will be 
+locked or none will be locked. -- end note]
+
      
+
+
+
+
+
+
      
+
      990. monotonic_clock::is_monotonic must be true
      
+
      Section: 20.9.5.2 [time.clock.monotonic] Status: WP
+ Submitter: Howard Hinnant Opened: 2009-03-09  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+There is some confusion over what the value of monotonic_clock::is_monotonic
+when monotonic_clock is a  synonym for system_clock.  The
+intent is that if monotonic_clock exists, then monotonic_clock::is_monotonic
+is true.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+We agree with the proposed resolution.
+
      
+
      
+Move to Tentatively Ready.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 20.9.5.2 [time.clock.monotonic], p1:
+
      
+
+
      
+-1- Objects of class monotonic_clock represent clocks for which
+values of time_point never decrease as physical time advances.
+monotonic_clock may be a synonym for system_clock
+if and only if system_clock::is_monotonic is
+true.
+
      
+
+
+
+
+
+
      
+
      991. Response to JP 50
      
+
      Section: 22.3.3.2.2 [conversions.string] Status: WP
+ Submitter: P.J. Plauger Opened: 2009-03-03  Last modified: 2009-07-18
      
+
      View all other issues in [conversions.string].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+Add custom allocator parameter to wstring_convert, since we cannot
+allocate memory for strings from a custom allocator.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 22.3.3.2.2 [conversions.string]:
+
      
+
+
      template<class Codecvt, class Elem = wchar_t,
+         class Wide_alloc = std::allocator<Elem>,
+         class Byte_alloc = std::allocator<char> > class wstring_convert {
+  public:
+    typedef std::basic_string<char, char_traits<char>, Byte_alloc> byte_string;
+    typedef std::basic_string<Elem, char_traits<Elem>, Wide_alloc> wide_string;
+     ...
+
      
+
+
      
+Change 22.3.3.2.2 [conversions.string], p3:
+
      
+
+
      
+-3- The class template describes an ob ject that controls conversions
+between wide string ob jects of class
+std::basic_string<Elem, char_traits<Elem>, Wide_alloc>
+and byte string objects of class
+std::basic_string<char, char_traits<char>, Byte_alloc>
+(also known as std::string).
+
      
+
+
+
+
+
+
+
      
+
      993. Response to UK 188
      
+
      Section: 18.5 [support.start.term] Status: WP
+ Submitter: P.J. Plauger Opened: 2009-03-03  Last modified: 2009-07-18
      
+
      View all other issues in [support.start.term].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+The function _Exit does not appear to be defined in this standard.
+Should it be added to the table of functions included-by-reference to
+the C standard?
+
      
+
+
      [
+2009-05-09 Alisdair fixed some minor issues in the wording.
+]
      
+
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Add to 18.5 [support.start.term] Table 20 (Header
+<cstdlib> synopsis) Functions:
+
      
+
+
      _Exit
+
      
+
+
      
+Add before the description of abort(void):
+
      
+
+
      void _Exit [[noreturn]] (int status)
+
      
+
+
      
+
      
+The function _Exit(int status) has additional behavior in this
+International Standard:
+
      
+
        
+
      • 
+The program is terminated without executing destructors for objects of
+automatic, thread, or static storage duration and without calling the
+functions passed to atexit() (3.6.3 [basic.start.term]).
+
        • 
+
      
+
      
+
      
+
+
+
+
+
+
+
      
+
      994. Response to UK 193
      
+
      Section: 18.6.2.2 [new.handler] Status: WP
+ Submitter: P.J. Plauger Opened: 2009-03-03  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+quick_exit has been added as a new valid way to terminate a program in a
+well defined way
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 18.6.2.2 [new.handler], p2:
+
      
+
+
      
+
      
+-2- Required behavior: ...
+
      
+
        
+
      • ...
        • 
+
      • 
+call either abort() or exit();
+terminate execution of the program without returning to the caller
+
        • 
+
      
+
      
+
+
+
+
+
+
+
+
      
+
      997. Response to UK 163
      
+
      Section: 17.5.1.4 [structure.specifications] Status: WP
+ Submitter: Thomas Plum Opened: 2009-03-03  Last modified: 2009-07-18
      
+
      View all other issues in [structure.specifications].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+Many functions are defined as "Effects: Equivalent to a...", which seems
+to also define the preconditions, effects, etc. But this is not made
+clear.
+
      
+
+
      
+After studying the occurrences of "Effects: Equivalent to", I agree with
+the diagnosis but disagree with the solution.  In 21.4.2 [string.cons]
+we find
+
      
+
+
      
+
      
+14 Effects: If InputIterator is an integral type, equivalent to
+basic_string(static_cast<size_type>(begin), static_cast<value_type>(end), a)
+
      
+
      
+15 Otherwise constructs a string from the values in the range [begin,
+end), as indicated in the Sequence Requirements table (see 23.1.3).
+
      
+
      
+
+
      
+This would be devishly difficult to re-write with an explicit
+"Equivalent to:" clause.  Instead, I propose the following, which will
+result in much less editorial re-work.
+
      
+
+
      [
+2009-05-09 Alisdair adds:
+]
      
+
+
+
      
+This issue is related to 492.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Add a new paragraph after 17.5.1.4 [structure.specifications], p3:
+
      
+
+
      
+
      
+-3- Descriptions of function semantics contain the following elements (as appropriate):154
+
      
+
+
        
+
      • 
+Requires: the preconditions for calling the function
+
        • 
+
      • 
+Effects: the actions performed by the function
+
        • 
+
      • 
+Postconditions: the observable results established by the function
+
        • 
+
      • 
+Returns: a description of the value(s) returned by the function
+
        • 
+
      • 
+Throws: any exceptions thrown by the function, and the conditions that would cause the exception
+
        • 
+
      • 
+Complexity: the time and/or space complexity of the function
+
        • 
+
      • 
+Remarks: additional semantic constraints on the function
+
        • 
+
      • 
+Error conditions: the error conditions for error codes reported by the function.
+
        • 
+
      • 
+Notes: non-normative comments about the function
+
        • 
+
      
+
+
      
+Whenever the Effects element specifies that the semantics of some
+function F are Equivalent to some code-sequence, then
+the various elements are interpreted as follows.  If F's
+semantics specifies a Requires element, then that requirement is
+logically imposed prior to the equivalent-to semantics.  Then,
+the semantics of the code-sequence are determined by the
+Requires, Effects, Postconditions, Returns,
+Throws, Complexity, Remarks, Error
+Conditions and Notes specified for the (one or more) function
+invocations contained in the code-sequence. The value returned from
+F is specified by F's Returns element, or
+if F has no Returns element, a non-void return from F is specified 
+by the Returns elements in code-sequence.  If
+F's semantics contains a Throws (or
+Postconditions, or Complexity) element, then that
+supersedes any occurrences of that element in the code-sequence.
+
      
+
      
+
+
+
+
+
+
+
      
+
      998. Smart pointer referencing its owner
      
+
      Section: 20.8.9.2.5 [unique.ptr.single.modifiers] Status: WP
+ Submitter: Pavel Minaev Opened: 2009-02-26  Last modified: 2009-07-18
      
+
      View all other issues in [unique.ptr.single.modifiers].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+Consider the following (simplified) implementation of 
+std::auto_ptr<T>::reset(): 
+
      
+
+
      void reset(T* newptr = 0) { 
+   if (this->ptr && this->ptr != newptr) { 
+     delete this->ptr; 
+   } 
+   this->ptr = newptr; 
+} 
+
      
+
+
      
+Now consider the following code which uses the above implementation: 
+
      
+
+
      struct foo { 
+   std::auto_ptr<foo> ap; 
+   foo() : ap(this) {} 
+   void reset() { ap.reset(); } 
+}; 
+int main() { 
+   (new foo)->reset(); 
+} 
+
      
+
+
      
+With the above implementation of auto_ptr, this results in U.B. at the 
+point of auto_ptr::reset(). If this isn't obvious yet, let me explain 
+how this goes step by step: 
+
      
+
+
        
+
      1. 
+foo::reset() entered 
+
        2. 
+
      2. 
+auto_ptr::reset() entered 
+
        3. 
+
      3. 
+auto_ptr::reset() tries to delete foo
+
        4. 
+
      4. 
+foo::~foo() entered, tries to destruct its members 
+
        5. 
+
      5. 
+auto_ptr::~auto_ptr() executed - auto_ptr is no longer a valid object! 
+
        6. 
+
      6. 
+foo::~foo() left 
+
        7. 
+
      7. 
+auto_ptr::reset() sets its "ptr" field to 0 <- U.B.! auto_ptr
+is not a valid object here already! 
+
        8. 
+
      
+
+
      [
+Thanks to Peter Dimov who recognized the connection to unique_ptr and
+brought this to the attention of the LWG, and helped with the solution.
+]
      
+
+
+
      [
+Howard adds:
+]
      
+
+
+
      
+To fix this behavior reset must be specified such that deleting the
+pointer is the last action to be taken within reset.
+
      
+
+
      [
+Alisdair adds:
+]
      
+
+
+
      
+
      
+The example providing the rationale for LWG 998 is poor, as it relies on
+broken semantics of having two object believing they are unique owners of a
+single resource.  It should not be surprising that UB results from such
+code, and I feel no need to go out of our way to support such behaviour.
+
      
+
      
+If an example is presented that does not imply multiple ownership of a
+unique resource, I would be much more ready to accept the proposed
+resolution.
+
      
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+Howard summarizes:
+
      
+
      
+This issue has to do with circular ownership,
+and affects auto_ptr, too (but we don't really care about that).
+It is intended to spell out the order in which operations must be performed
+so as to avoid the possibility
+of undefined behavior in the self-referential case.
+
      
+
      
+Howard points to message c++std-lib-23175 for another example,
+requested by Alisdair.
+
      
+
      
+We agree with the issue and with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
      
+
+
+
+
      Proposed resolution:
      
+
      
+Change 20.8.9.2.5 [unique.ptr.single.modifiers], p5 (Effects clause for reset), and p6:
+
      
+
+
      
+
      
+-5- Effects: If get() == nullptr there are no effects. Otherwise get_deleter()(get()).
+Assigns p to the stored pointer, and then if the old value of the pointer is not
+equal to nullptr, calls get_deleter()(the old value of the pointer).
+[Note: The order of these operations is significant because the call to get_deleter()
+may destroy *this. -- end note]
+
      
+
+
      
+-6- Postconditions: get() == p.
+[Note: The postcondition does not hold if the call to
+get_deleter() destroys *this since this->get() is no longer a valid
+expression. -- end note]
+
      
+
      
+
+
+
+
+
+
      
+
      1006. operator delete in garbage collected implementation
      
+
      Section: 18.6.1 [new.delete] Status: WP
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-18
      
+
      View all other issues in [new.delete].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses UK 190
      
+
+
      
+It is not entirely clear how the current specification acts in the
+presence of a garbage collected implementation.
+
      
+
+
      [
+Summit:
+]
      
+
+ 
+
      
+Agreed.
+
      
+
+
      [
+2009-05-09 Alisdair adds:
+]
      
+
+
+
      
+Proposed wording is too strict for implementations that do not support
+garbage collection.  Updated wording supplied.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We recommend advancing this to Tentatively Ready
+with the understanding that it will not be moved for adoption
+unless and until the proposed resolution to Core issue #853 is adopted.
+
      
+
+
+
      Proposed resolution:
      
+
+
      
+(Editorial note: This wording ties into the proposed
+resolution for Core #853)
+
      
+
+
      
+Add paragraphs to 18.6.1.1 [new.delete.single]:
+
      
+
+
      void operator delete(void* ptr) throw();
+void operator delete(void* ptr, const std::nothrow_t&) throw();
+
      
+
+
      [
+The second signature deletion above is editorial.
+]
      
+
+
+
      
+
      
+Requires: If an implementation has strict pointer safety
+(3.7.4.3 [basic.stc.dynamic.safety]) then ptr shall
+be a safely-derived pointer.
+
      
+
+
      -10- ...
      
+
      
+
+
      void operator delete(void* ptr, const std::nothrow_t&) throw();
+
      
+
+
      
+
      
+Requires: If an implementation has strict pointer safety
+(3.7.4.3 [basic.stc.dynamic.safety]) then ptr shall
+be a safely-derived pointer.
+
      
+
+
      -15- ...
      
+
      
+
+
      
+
+
      
+Add paragraphs to 18.6.1.2 [new.delete.array]:
+
      
+
+
      void operator delete[](void* ptr) throw();
+void operator delete[](void* ptr, const std::nothrow_t&) throw();
+
      
+
+
      [
+The second signature deletion above is editorial.
+]
      
+
+
+
      
+
      
+Requires: If an implementation has strict pointer safety
+(3.7.4.3 [basic.stc.dynamic.safety]) then ptr shall
+be a safely-derived pointer.
+
      
+
+
      -9- ...
      
+
      
+
+
      void operator delete[](void* ptr, const std::nothrow_t&) throw();
+
      
+
+
      
+
      
+Requires: If an implementation has strict pointer safety
+(3.7.4.3 [basic.stc.dynamic.safety]) then ptr shall
+be a safely-derived pointer.
+
      
+
+
      -13- ...
      
+
      
+
+
      
+
+
+
      
+Add paragraphs to 18.6.1.3 [new.delete.placement]:
+
      
+
+
      void operator delete(void* ptr, void*) throw();
+
      
+
+
      
+
      
+Requires: If an implementation has strict pointer safety
+(3.7.4.3 [basic.stc.dynamic.safety]) then ptr shall
+be a safely-derived pointer.
+
      
+
+
      -7- ...
      
+
      
+
+
      void operator delete[](void* ptr, void*) throw();
+
      
+
+
      
+
      
+Requires: If an implementation has strict pointer safety
+(3.7.4.3 [basic.stc.dynamic.safety]) then ptr shall
+be a safely-derived pointer.
+
      
+
+
      -9- ...
      
+
      
+
+
      
+
+
+
+
+
+
+
      
+
      1014. Response to UK 317 and JP 74
      
+
      Section: 28.8.2 [re.regex.construct] Status: WP
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-18
      
+
      View all other issues in [re.regex.construct].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses UK 317 and JP 74
      
+
+
      
+UK 317:
+
      
+
+
      
+basic_string has both a constructor and an assignment operator that
+accepts an initializer list, basic_regex should have the same.
+
      
+
+
      
+JP 74:
+
      
+
+
      
+basic_regx & operator= (initializer_list<T>); is not defined.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+UK 317 asks for both assignment and constructor,
+but the requested constructor is already present in the current Working Paper.
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 28.8 [re.regex]:
+
      
+
+
      template <class charT,
+          class traits = regex_traits<charT> >
+class basic_regex {
+  ...
+  basic_regex& operator=(const charT* ptr);
+  basic_regex& operator=(initializer_list<charT> il);
+  template <class ST, class SA>
+    basic_regex& operator=(const basic_string<charT, ST, SA>& p);
+  ...
+};
+
      
+
+
      
+Add in  28.8.2 [re.regex.construct]:
+
      
+
+
      
+
      
+-20- ...
+
      
+
      basic_regex& operator=(initializer_list<charT> il);
+
      
+
      
+-21- Effects: returns assign(il.begin(), il.end());
+
      
+
      
+
+
+
+
+
+
+
      
+
      1021. Response to UK 211
      
+
      Section: 20.8.9.2.3 [unique.ptr.single.asgn] Status: WP
+ Submitter: Alisdair Meredith Opened: 2009-03-11  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses UK 211
      
+
+
      
+The nullptr_t type was introduced to resolve the null pointer literal
+problem. It should be used for the assignemnt operator, as with the
+constructor and elsewhere through the library.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change the synopsis in 20.8.9.2 [unique.ptr.single]:
+
      
+
+
      unique_ptr& operator=(unspecified-pointer-type nullptr_t);
+
      
+
+
      
+Change 20.8.9.2.3 [unique.ptr.single.asgn]:
+
      
+
+
      unique_ptr& operator=(unspecified-pointer-type nullptr_t);
+
      
+
      
+Assigns from the literal 0 or NULL. [Note: The
+unspecified-pointer-type is often implemented as a pointer to a
+private data member, avoiding many of the implicit conversion pitfalls.
+-- end note]
+
      
+
      
+
+
+
+
+
+
      
+
      1037. Response to UK 232
      
+
      Section: 23.2.3 [sequence.reqmts] Status: WP
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
      
+
      View all other issues in [sequence.reqmts].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses UK 232
      
+
+
      
+match_results may follow the requirements but is not listed a general
+purpose library container.
+
      
+
+
      
+Remove reference to match_results against a[n] operation.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Agree. operator[] is defined elsewhere.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+In 23.2.3 [sequence.reqmts] Table 84, remove reference to
+match_results in the row describing the a[n] operation.
+
      
+
+
+
+
+
+
      
+
      1038. Response to UK 233
      
+
      Section: 23.2.3 [sequence.reqmts] Status: WP
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
      
+
      View all other issues in [sequence.reqmts].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses UK 233
      
+
+
      
+Table 84 is missing references to several new container types.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Agree.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+In 23.2.3 [sequence.reqmts] Table 84, Add reference to listed
+containers to the following rows:
+
      
+
+
      
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
      Table 84 -- Optional sequence container operations
      ExpressionReturn typeOperational semanticsContainer
      a.front()......vector, list, deque, basic_string, array, forward_list
      a.back()......vector, list, deque, basic_string, array
      a.emplace_front(args)......list, deque, forward_list
      a.push_front(t)......list, deque, forward_list
      a.push_front(rv)......list, deque, forward_list
      a.pop_front()......list, deque, forward_list
      a[n]......vector, deque, basic_string, array
      a.at(n)......vector, deque, basic_string, array
      
+
      
+
+
+
+
+
+
      
+
      1039. Response to UK 234
      
+
      Section: 23.2.3 [sequence.reqmts] Status: WP
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
      
+
      View all other issues in [sequence.reqmts].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses UK 234
      
+
+
      
+The reference to iterator in semantics for back should
+also allow for const_iterator when called on a const-qualified
+container. This would be ugly to specify in the 03 standard, but is
+quite easy with the addition of auto in this new standard.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Agree.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+In 23.2.3 [sequence.reqmts] Table 84, replace iterator with auto in semantics for back:
+
      
+
+
      
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
      Table 84 -- Optional sequence container operations
      ExpressionReturn typeOperational semanticsContainer
      a.back()reference; const_reference for constant a{ iterator auto tmp = a.end();
      --tmp;
      return *tmp; }      		vector, list, deque, basic_string
      
+
      
+
+
+
+
+
+
      
+
      1040. Response to UK 238
      
+
      Section: 23.2.4 [associative.reqmts] Status: WP
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
      
+
      View all other issues in [associative.reqmts].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses UK 238
      
+
+
      
+Leaving it unspecified whether or not iterator and const_iterator are the
+same type is dangerous, as user code may or may not violate the One
+Definition Rule by providing overloads for 
+both types. It is probably too late to specify a single behaviour, but
+implementors should document what to expect. Observing that problems can be
+avoided by users restricting themselves to using const_iterator, add a note to that effect. 
+
      
+
      
+Suggest Change 'unspecified' to 'implementation defined'.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Agree with issue. Agree with adding the note but not with changing the
+normative text. We believe the note provides sufficient guidance.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+In 23.2.4 [associative.reqmts] p6, add:
+
      
+
+
      
+-6- iterator of an associative container meets the requirements
+of the BidirectionalIterator concept. For associative
+containers where the value type is the same as the key type, both
+iterator and const_iterator are constant iterators. It
+is unspecified whether or not iterator and
+const_iterator are the same type.
+[Note: iterator and const_iterator have identical semantics in
+this case, and iterator is convertible to const_iterator. Users can avoid
+violating the One Definition Rule by always using const_iterator
+in their function parameter lists -- end note]
+
      
+
+
+
+
+
+
      
+
      1044. Response to UK 325
      
+
      Section: 30.4 [thread.mutex] Status: WP
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses UK 325
      
+
+
      
+We believe constexpr literal values should be a more natural expression
+of empty tag types than extern objects as it should improve the
+compiler's ability to optimize the empty object away completely.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Move to review. The current specification is a "hack", and the proposed
+specification is a better "hack".
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change the synopsis in 30.4 [thread.mutex]:
+
      
+
+
      struct defer_lock_t {};
+struct try_to_lock_t {};
+struct adopt_lock_t {};
+
+extern constexpr defer_lock_t defer_lock {};
+extern constexpr try_to_lock_t try_to_lock {};
+extern constexpr adopt_lock_t adopt_lock {};
+
      
+
+
+
+
+
+
+
      
+
      1045. Response to UK 326
      
+
      Section: 30.4.3.2.1 [thread.lock.unique.cons] Status: WP
+ Submitter: Alisdair Meredith Opened: 2009-03-12  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      Addresses UK 326
      
+
+
      
+The precondition that the mutex is not owned by this thread offers
+introduces the risk of un-necessary undefined behaviour into the
+program. The only time it matters whether the current thread owns the
+mutex is in the lock operation, and that will happen subsequent to
+construction in this case. The lock operation has the identical
+pre-condition, so there is nothing gained by asserting that precondition
+earlier and denying the program the right to get into a valid state
+before calling lock.
+
      
+
+
      [
+Summit:
+]
      
+
+
+
      
+Agree, move to review.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Strike 30.4.3.2.1 [thread.lock.unique.cons] p7:
+
      
+
+
      unique_lock(mutex_type& m, defer_lock_t);
+
      
+
      
+-7- Precondition: If mutex_type is not a recursive mutex
+the calling thread does not own the mutex.
+
      
+
      
+
+
+
+
+
+
+
      
+
      1065. Response to UK 168
      
+
      Section: 17.6.1.1 [contents] Status: WP
+ Submitter: Howard Hinnant Opened: 2009-03-15  Last modified: 2009-07-18
      
+
      View all other issues in [contents].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      Addresses UK 168
      
+
      
+We should make it clear (either by note or normatively) that namespace
+std may contain inline namespaces, and that entities specified to be
+defined in std may in fact be defined in one of these inline namespaces.
+(If we're going to use them for versioning, eg when TR2 comes along,
+we're going to need that.)
+
      
+
+
      
+Replace "namespace std or namespaces nested within namespace std" with
+"namespace std or namespaces nested within namespace std or inline
+namespaces nested directly or indirectly within namespace std"
+
      
+
+
      [
+Summit:
+]
      
+
+
      
+adopt UK words (some have reservations whether it is correct)
+
      
+
+
      [
+2009-05-09 Alisdair improves the wording.
+]
      
+
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+Bill believes there is strictly speaking no need to say that
+because no portable test can detect the difference.
+However he agrees that it doesn't hurt to say this.
+
      
+
      
+Move to Tentatively Ready.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 17.6.1.1 [contents] p2:
+
      
+
+
      
+All library entities except macros, operator new and
+operator delete are defined within the namespace std or
+namespaces nested within namespace std.
+It is unspecified whether names declared in a specific namespace
+are declared directly in that namespace, or in an inline namespace inside
+that namespace. [Footnote: This gives implementers freedom to support
+multiple configurations of the library.]
+
      
+
+
+
+
+
+
      
+
      1066. Response to UK 189 and JP 27
      
+
      Section: 18 [language.support] Status: WP
+ Submitter: Howard Hinnant Opened: 2009-03-15  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      Addresses UK 189 and JP 27
      
+
      
+The addition of the [[noreturn]] attribute to the language will be an
+important aid for static analysis tools.
+
      
+
+
      
+The following functions should be declared in C++ with the
+[[noreturn]] attribute: abort exit
+quick_exit terminate unexpected
+rethrow_exception throw_with_nested.
+
      
+
+
      [
+Summit:
+]
      
+
+
      
+Agreed.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.
+Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 18.5 [support.start.term] p3:
+
      
+
+
      
+
      -2- ...
      
+
      void abort [[noreturn]] (void)
+
      
+
      -3- ...
      
+
      -6- ...
      
+
      void exit [[noreturn]] (int status)
+
      
+
      -7- ...
      
+
      -11- ...
      
+
      void quick_exit [[noreturn]] (int status)
+
      
+
      -12- ...
      
+
      
+
+
      
+Change the <exception> synopsis in 18.8 [support.exception]:
+
      
+
+
      void unexpected [[noreturn]] ();
+...
+void terminate [[noreturn]] ();
+...
+void rethrow_exception [[noreturn]] (exception_ptr p);
+...
+template <class T> void throw_with_nested [[noreturn]] (T&& t); // [[noreturn]]
+
      
+
+
      
+Change 18.8.2.4 [unexpected]:
+
      
+
+
      void unexpected [[noreturn]] ();
+
      
+
+
      
+Change 18.8.3.3 [terminate]:
+
      
+
+
      void terminate [[noreturn]] ();
+
      
+
+
      
+Change 18.8.5 [propagation]:
+
      
+
+
      void rethrow_exception [[noreturn]] (exception_ptr p);
+
      
+
+
      
+In the synopsis of 18.8.6 [except.nested] and the definition area change:
+
      
+
+
      template <class T> void throw_with_nested [[noreturn]] (T&& t); // [[noreturn]]
+
      
+
+
+
+
+
+
      
+
      1070. Ambiguous move overloads in function
      
+
      Section: 20.7.16.2 [func.wrap.func] Status: WP
+ Submitter: Howard Hinnant Opened: 2009-03-19  Last modified: 2009-07-18
      
+
      View all other issues in [func.wrap.func].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+The synopsis in 20.7.16.2 [func.wrap.func] says:
+
      
+
+
      template<Returnable R, CopyConstructible... ArgTypes> 
+class function<R(ArgTypes...)>
+{
+    ...
+    template<class F> 
+      requires CopyConstructible<F> && Callable<F, ArgTypes...> 
+            && Convertible<Callable<F, ArgTypes...>::result_type, R> 
+      function(F); 
+    template<class F> 
+      requires CopyConstructible<F> && Callable<F, ArgTypes...> 
+            && Convertible<Callable<F, ArgTypes...>::result_type, R> 
+      function(F&&);
+    ...
+    template<class F, Allocator Alloc> function(allocator_arg_t, const Alloc&, F); 
+    template<class F, Allocator Alloc> function(allocator_arg_t, const Alloc&, F&&);
+    ...
+    template<class F> 
+      requires CopyConstructible<F> && Callable<F, ArgTypes..> 
+            && Convertible<Callable<F, ArgTypes...>::result_type 
+      function& operator=(F); 
+    template<class F> 
+      requires CopyConstructible<F> && Callable<F, ArgTypes...> 
+            && Convertible<Callable<F, ArgTypes...>::result_type, R> 
+      function& operator=(F&&);
+    ...
+};
+
      
+
+
      
+Each of the 3 pairs above are ambiguous.  We need only one of each pair, and we
+could do it with either one.  If we choose the F&& version we
+need to bring decay into the definition to get the pass-by-value behavior.
+In the proposed wording I've gotten lazy and just used the pass-by-value signature.
+
      
+
+
      [
+2009-05-01 Daniel adds:
+]
      
+
+
+
      
+1024 modifies the second removed constructor.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+
      
+We briefly discussed whether we ought support moveable function objects,
+but decided that should be a separate issue if someone cares to propose it.
+
      
+
      
+Move to Tentatively Ready.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change the synopsis of 20.7.16.2 [func.wrap.func], and remove the associated definitions in
+20.7.16.2.1 [func.wrap.func.con]:
+
      
+
+
      template<Returnable R, CopyConstructible... ArgTypes> 
+class function<R(ArgTypes...)>
+{
+    ...
+    template<class F> 
+      requires CopyConstructible<F> && Callable<F, ArgTypes...> 
+            && Convertible<Callable<F, ArgTypes...>::result_type, R> 
+      function(F); 
+    template<class F> 
+      requires CopyConstructible<F> && Callable<F, ArgTypes...> 
+            && Convertible<Callable<F, ArgTypes...>::result_type, R> 
+      function(F&&);
+    ...
+    template<class F, Allocator Alloc> function(allocator_arg_t, const Alloc&, F); 
+    template<class F, Allocator Alloc> function(allocator_arg_t, const Alloc&, F&&);
+    ...
+    template<class F> 
+      requires CopyConstructible<F> && Callable<F, ArgTypes..> 
+            && Convertible<Callable<F, ArgTypes...>::result_type 
+      function& operator=(F); 
+    template<class F> 
+      requires CopyConstructible<F> && Callable<F, ArgTypes...> 
+            && Convertible<Callable<F, ArgTypes...>::result_type, R> 
+      function& operator=(F&&);
+    ...
+};
+
      
+
+
+
+
+
+
+
      
+
      1073. Declaration of allocator_arg should be constexpr
      
+
      Section: 20.8 [memory] Status: WP
+ Submitter: Alisdair Meredith Opened: 2009-03-19  Last modified: 2009-07-18
      
+
      View all other issues in [memory].
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
+
      
+Declaration of allocator_arg should be constexpr to ensure constant
+initialization.
+
      
+
+
      [
+Batavia (2009-05):
+]
      
+
+
      
+We agree with the proposed resolution.  Move to Tentatively Ready.
+
      
+
+
+
      Proposed resolution:
      
+
      
+Change 20.8 [memory] p2:
+
      
+
+
      // 20.8.1, allocator argument tag
+struct allocator_arg_t { };
+constexpr allocator_arg_t allocator_arg = allocator_arg_t();
+
      
+
+
+
+
+
+
+
      
+
      1103. system_error constructor postcondition overly strict
      
+
      Section: 19.5.5.2 [syserr.syserr.members] Status: WP
+ Submitter: Howard Hinnant Opened: 2009-04-25  Last modified: 2009-07-18
      
+
      View all issues with WP status.
      
+
      Discussion:
      
+
      
+19.5.5.2 [syserr.syserr.members] says:
+
      
+
+
      system_error(error_code ec, const string& what_arg);
+
      
+
      
+
      
+Effects: Constructs an object of class system_error.
+
      
+
      
+Postconditions: code() == ec and strcmp(runtime_error::what(), what_arg.c_str()) == 0.
+
      
+
      
+
      
+
+
      
+However the intent is for:
+
      
+
+
      std::system_error se(std::errc::not_a_directory, "In FooBar");
+...
+se.what();  // returns something along the lines of:
+            //   "In FooBar: Not a directory"
+
      
+
+
      
+The way the constructor postconditions are set up now, to achieve both
+conformance, and the desired intent in the what() string, the
+system_error constructor must store "In FooBar" in the base class,
+and then form the desired output each time what() is called.  Or
+alternatively, store "In FooBar" in the base class, and store the desired
+what() string in the derived system_error, and override
+what() to return the string in the derived part.
+
      
+
+
      
+Both of the above implementations seem suboptimal to me.  In one I'm computing
+a new string every time what() is called.  And since what()
+can't propagate exceptions, the client may get a different string on different
+calls.
+
      
+
+
      
+The second solution requires storing two strings instead of one.
+
      
+
+
      
+What I would like to be able to do is form the desired what() string
+once in the system_error constructor, and store that in the
+base class.  Now I'm:
+
      
+
+
        
+
      1. Computing the desired what() only once.
        2. 
+
      2. The base class what() definition is sufficient and nothrow.
        3. 
+
      3. I'm not storing multiple strings.
        4. 
+
      
+
+
      
+This is smaller code, smaller data, and faster.
+
      
+
+
      
+ios_base::failure has the same issue.
+
      
+
+
      [
+Comments about this change received favorable comments from the system_error
+designers.
+]
      
+
+
+
      [
+Batavia (2009-05):
+]
      
+
+
+
      
+
      
+We agree with the proposed resolution.
+
      
+
      
+Move to Tentatively Ready.
+
      
+
      
+
+
+
      Proposed resolution:
      
+
      
+In 19.5.5.2 [syserr.syserr.members], change the following constructor postconditions:
+
      
+
+
      
+
      system_error(error_code ec, const string& what_arg);
+
      
+
      
+-2- Postconditions: code() == ec
+and strcmp(runtime_error::what(), what_arg.c_str()) == 0
+string(what()).find(what_arg) != string::npos.
+
      
+
+
      system_error(error_code ec, const char* what_arg);
+
      
+
      
+-4- Postconditions: code() == ec
+and strcmp(runtime_error::what(), what_arg) == 0
+string(what()).find(what_arg) != string::npos.
+
      
+
+
      system_error(error_code ec);
+
      
+
      
+-6- Postconditions: code() == ec
+and strcmp(runtime_error::what(), "".
+
      
+
+
      system_error(int ev, const error_category& ecat, const string& what_arg);
+
      
+
      
+-8- Postconditions: code() == error_code(ev, ecat)
+and strcmp(runtime_error::what(), what_arg.c_str()) == 0
+string(what()).find(what_arg) != string::npos.
+
      
+
+
      system_error(int ev, const error_category& ecat, const char* what_arg);
+
      
+
      
+-10- Postconditions: code() == error_code(ev, ecat)
+and strcmp(runtime_error::what(), what_arg) == 0
+string(what()).find(what_arg) != string::npos.
+
      
+
+
      system_error(int ev, const error_category& ecat);
+
      
+
      
+-12- Postconditions: code() == error_code(ev, ecat)
+and strcmp(runtime_error::what(), "") == 0.
+
      
+
+
      
+
+
      
+In 19.5.5.2 [syserr.syserr.members], change the description of what():
+
      
+
+
      
+
      const char *what() const throw();
+
      
+
      
+
      
+-14- Returns: An NTBS incorporating runtime_error::what() and
+code().message() the arguments supplied in the constructor.
+
      
+
      
+[Note: One possible implementation would be:
+The return NTBS might take the form: what_arg + ": " + code().message()
+
      
+
      
+if (msg.empty()) { 
+  try { 
+    string tmp = runtime_error::what(); 
+    if (code()) { 
+      if (!tmp.empty()) 
+        tmp += ": "; 
+      tmp += code().message(); 
+    } 
+    swap(msg, tmp); 
+  } catch(...) { 
+    return runtime_error::what(); 
+  } 
+return msg.c_str();
+
      
+
      
+— end note]
+
      
+
      
+
      
+
+
      
+In 27.5.2.1.1 [ios::failure], change the synopsis:
+
      
+
+
      namespace std { 
+  class ios_base::failure : public system_error { 
+  public: 
+    explicit failure(const string& msg, const error_code& ec = io_errc::stream); 
+    explicit failure(const char* msg, const error_code& ec = io_errc::stream); 
+    virtual const char* what() const throw();
+  }; 
+}
+
      
+
+
      
+In 27.5.2.1.1 [ios::failure], change the description of the constructors:
+
      
+
+
      
+
+
      explicit failure(const string& msg, , const error_code& ec = io_errc::stream);
+
      
+
      
+
      
+-3- Effects: Constructs an object of class failure
+by constructing the base class with msg and ec.
+
      
+
      
+-4- Postcondition: code() == ec and strcmp(what(), msg.c_str()) == 0
+
      
+
      
+
+
      explicit failure(const char* msg, const error_code& ec = io_errc::stream);
+
      
+
      
+
      
+-5- Effects: Constructs an object of class failure
+by constructing the base class with msg and ec.
+
      
+
      
+-6- Postcondition: code() == ec and strcmp(what(), msg) == 0
+
      
+
      
+
+
      
+
+
      
+In 27.5.2.1.1 [ios::failure], remove what (the base class definition
+need not be repeated here).
+
      
+
+
      
+
      const char* what() const;
+
      
+
      
+-7- Returns: The message msg with which the exception was created.
+
      
+
+
      
+
+
+
+
+
+
 
\ No newline at end of file
diff --git a/libstdc++-v3/doc/xml/manual/intro.xml b/libstdc++-v3/doc/xml/manual/intro.xml
index 28b80c9..2fcdeb1 100644
--- a/libstdc++-v3/doc/xml/manual/intro.xml
+++ b/libstdc++-v3/doc/xml/manual/intro.xml
@@ -798,7 +798,7 @@ requirements of the license of GCC.
     In C++0x mode, remove the pow(complex<T>, int) signature.
     
 
-    853:
+    853:
         to_string needs updating with zero and one
     
     Update / add the signatures.
-- 
2.7.4