features.
This document is meant to help you to find out what constitutes portable
-perl code, so that once you have made your decision to write portably,
+Perl code, so that once you have made your decision to write portably,
you know where the lines are drawn, and you can stay within them.
There is a tradeoff between taking full advantage of B<a> particular type
-of computer, and taking advantage of a full B<range> of them. Naturally,
-as you make your range bigger (and thus more diverse), the common denominators
-drop, and you are left with fewer areas of common ground in which
-you can operate to accomplish a particular task. Thus, when you begin
-attacking a problem, it is important to consider which part of the tradeoff
-curve you want to operate under. Specifically, whether it is important to
-you that the task that you are coding needs the full generality of being
-portable, or if it is sufficient to just get the job done. This is the
-hardest choice to be made. The rest is easy, because Perl provides lots
-of choices, whichever way you want to approach your problem.
-
-Looking at it another way, writing portable code is usually about willfully
-limiting your available choices. Naturally, it takes discipline to do that.
+of computer, and taking advantage of a full B<range> of them. Naturally,
+as you make your range bigger (and thus more diverse), the common
+denominators drop, and you are left with fewer areas of common ground in
+which you can operate to accomplish a particular task. Thus, when you
+begin attacking a problem, it is important to consider which part of the
+tradeoff curve you want to operate under. Specifically, whether it is
+important to you that the task that you are coding needs the full
+generality of being portable, or if it is sufficient to just get the job
+done. This is the hardest choice to be made. The rest is easy, because
+Perl provides lots of choices, whichever way you want to approach your
+problem.
+
+Looking at it another way, writing portable code is usually about
+willfully limiting your available choices. Naturally, it takes discipline
+to do that.
Be aware of two important points:
often the case with systems programming (whether for Unix, Windows,
S<Mac OS>, VMS, etc.), consider writing platform-specific code.
-When the code will run on only two or three operating systems, then you may
-only need to consider the differences of those particular systems. The
-important thing is to decide where the code will run, and to be deliberate
-in your decision.
+When the code will run on only two or three operating systems, then you
+may only need to consider the differences of those particular systems.
+The important thing is to decide where the code will run, and to be
+deliberate in your decision.
+
+The material below is separated into three main sections: main issues of
+portability (L<"ISSUES">, platform-specific issues (L<"PLATFORMS">, and
+builtin perl functions that behave differently on various ports
+(L<"FUNCTION IMPLEMENTATIONS">.
This information should not be considered complete; it includes possibly
transient information about idiosyncrasies of some of the ports, almost
(E<lt>IMG SRC="yellow_sign.gif" ALT="Under Construction"E<gt>).
+
+
=head1 ISSUES
=head2 Newlines
with arbitrary values quite safely.
A common misconception in socket programming is that C<\n> eq C<\012>
-everywhere. When using protocols, such as common Internet protocols,
+everywhere. When using protocols such as common Internet protocols,
C<\012> and C<\015> are called for specifically, and the values of
the logical C<\n> and C<\r> (carriage return) are not reliable.
which translates those characters, along with all other
characters in text streams, from EBCDIC to ASCII.]
-However, C<\015\012> (or C<\cM\cJ>, or C<\x0D\x0A>) can be tedious and
-unsightly, as well as confusing to those maintaining the code. As such,
-the C<Socket> module supplies the Right Thing for those who want it.
+However, using C<\015\012> (or C<\cM\cJ>, or C<\x0D\x0A>) can be tedious
+and unsightly, as well as confusing to those maintaining the code. As
+such, the C<Socket> module supplies the Right Thing for those who want it.
use Socket qw(:DEFAULT :crlf);
print SOCKET "Hi there, client!$CRLF" # RIGHT
how that path is actually written, differs.
While they are similar, file path specifications differ between Unix,
-Windows, S<Mac OS>, OS/2, VMS, S<RISC OS> and probably others. Unix,
-for example, is one of the few OSes that has the idea of a root directory.
-S<Mac OS> uses C<:> as a path separator instead of C</>. VMS, Windows, and
-OS/2 can work similarly to Unix with C</> as path separator, or in their own
-idiosyncratic ways. C<RISC OS> perl can emulate Unix filenames with C</>
-as path separator, or go native and use C<.> for path separator and C<:>
-to signal filing systems and disc names.
+Windows, S<Mac OS>, OS/2, VMS, S<RISC OS> and probably others. Unix, for
+example, is one of the few OSes that has the idea of a root directory.
+S<Mac OS> uses C<:> as a path separator instead of C</>. VMS, Windows,
+and OS/2 can work similarly to Unix with C</> as path separator, or in
+their own idiosyncratic ways. C<RISC OS> perl can emulate Unix filenames
+with C</> as path separator, or go native and use C<.> for path separator
+and C<:> to signal filing systems and disc names.
As with the newline problem above, there are modules that can help. The
C<File::Spec> modules provide methods to do the Right Thing on whatever
description of the file and its format in the code's documentation, and
make it easy for the user to override the default location of the file.
-Don't assume that a you can open a full pathname for input with
-C<open (FILE, $name)>, as some platforms can use characters such as C<E<lt>>
-which will perl C<open> will interpret and eat.
-
Do not have two files of the same name with different case, like
F<test.pl> and <Test.pl>, as many platforms have case-insensitive
filenames. Also, try not to have non-word characters (except for C<.>)
-in the names, and keep them to the 8.3 convention, for maximum portability.
+in the names, and keep them to the 8.3 convention, for maximum
+portability.
Likewise, if using C<AutoSplit>, try to keep the split functions to
8.3 naming and case-insensitive conventions; or, at the very least,
make it so the resulting files have a unique (case-insensitively)
first 8 characters.
+Don't assume C<E<lt>> won't be the first character of a filename. Always
+use C<E<gt>> explicitly to open a file for reading:
+
+ open(FILE, "<$existing_file") or die $!;
+
=head2 System Interaction
Don't C<unlink> or C<rename> an open file. Don't C<tie> to or C<open> a
file that is already tied to or opened; C<untie> or C<close> first.
+Don't open the same file more than once at a time for writing, as some
+operating systems put mandatory locks on such files.
+
Don't count on a specific environment variable existing in C<%ENV>.
-Don't even count on C<%ENV> entries being case-sensitive, or even
+Don't count on C<%ENV> entries being case-sensitive, or even
case-preserving.
-Don't count on signals in portable programs.
+Don't count on signals.
Don't count on filename globbing. Use C<opendir>, C<readdir>, and
C<closedir> instead.
=head2 Interprocess Communication (IPC)
In general, don't directly access the system in code that is meant to be
-portable. That means, no
: C<system>, C<exec>, C<fork>, C<pipe>, C<``>,
-C<qx//>, C<open> with a C<|>, or any of the other things that makes being
+portable. That means, no C<system>, C<exec>, C<fork>, C<pipe>, C<``>,
+C<qx//>, C<open> with a C<|>, nor any of the other things that makes being
a Unix perl hacker worth being.
Commands that launch external processes are generally supported on
(via C<Net::SMTP>) if a mail transfer agent is not available.
The rule of thumb for portable code is: Do it all in portable Perl, or
-use a module that may internally implement it with platform-specific code,
-but expose a common interface. By portable Perl, we mean code that
-avoids the constructs described in this document as being non-portable.
+use a module (that may internally implement it with platform-specific
+code, but expose a common interface).
=head2 External Subroutines (XS)
normally reasonable to make sure the XS code is portable, too.
There is a different kind of portability issue with writing XS
-code: availability of a C compiler on the end-user's system. C brings with
-it its own portability issues, and writing XS code will expose you to
+code: availability of a C compiler on the end-user's system. C brings
+with it its own portability issues, and writing XS code will expose you to
some of those. Writing purely in perl is a comparatively easier way to
achieve portability.
There is no one DBM module that is available on all platforms.
C<SDBM_File> and the others are generally available on all Unix and DOSish
-ports, but not in MacPerl, where C<NBDM_File> and C<DB_File> are available.
+ports, but not in MacPerl, where only C<NBDM_File> and C<DB_File> are
+available.
The good news is that at least some DBM module should be available, and
C<AnyDBM_File> will use whichever module it can find. Of course, then
=head2 Time and Date
-The system's notion of time of day and calendar date is controlled in widely
-different ways. Don't assume the timezone is stored in C<$ENV{TZ}>, and even
-if it is, don't assume that you can control the timezone through that
-variable.
+The system's notion of time of day and calendar date is controlled in
+widely different ways. Don't assume the timezone is stored in C<$ENV{TZ}>,
+and even if it is, don't assume that you can control the timezone through
+that variable.
Don't assume that the epoch starts at January 1, 1970, because that is
OS-specific. Better to store a date in an unambiguous representation.
=head2 System Resources
-If your code is destined for systems with severely constrained (or missing!)
-virtual memory systems then you want to be especially mindful of avoiding
-wasteful constructs such as:
+If your code is destined for systems with severely constrained (or
+missing!) virtual memory systems then you want to be I<especially> mindful
+of avoiding wasteful constructs such as:
# NOTE: this is no longer "bad" in perl5.005
for (0..10000000) {} # bad
@lines = <VERY_LARGE_FILE>; # bad
while (<FILE>) {$file .= $_} # sometimes bad
- $file = join '', <FILE>; # better
+ $file = join('', <FILE>); # better
The last two may appear unintuitive to most people. The first of those
two constructs repeatedly grows a string, while the second allocates a
large chunk of memory in one go. On some systems, the latter is more
efficient that the former.
+
=head2 Security
-Most multi-user platforms provide basic levels of security that is usually felt
-at the file-system level. Other platforms usually don't (unfortunately).
-Thus the notion of User-ID, or "home" directory, or even the state of
-being logged-in may be unrecognizable on many platforms. If you write
-programs that are security conscious, it is usually best to know what
-type of system you will be operating under, and write code explicitly
+Most multi-user platforms provide basic levels of security that is usually
+felt at the file-system level. Other platforms usually don't
+(unfortunately). Thus the notion of user id, or "home" directory, or even
+the state of being logged-in, may be unrecognizable on many platforms. If
+you write programs that are security conscious, it is usually best to know
+what type of system you will be operating under, and write code explicitly
for that platform (or class of platforms).
+
=head2 Style
For those times when it is necessary to have platform-specific code,
consider keeping the platform-specific code in one place, making porting
to other platforms easier. Use the C<Config> module and the special
-variable C<$^O> to differentiate platforms, as described in L<"PLATFORMS">.
+variable C<$^O> to differentiate platforms, as described in
+L<"PLATFORMS">.
-=head1 CPAN TESTERS
+=head1 CPAN Testers
-Module uploaded to CPAN are tested by a variety of volunteers on
-different platforms. These CPAN testers are notified by e-mail of each
+Modules uploaded to CPAN are tested by a variety of volunteers on
+different platforms. These CPAN testers are notified by mail of each
new upload, and reply to the list with PASS, FAIL, NA (not applicable to
-this platform), or ???? (unknown), along with any relevant notations.
+this platform), or UNKNOWN (unknown), along with any relevant notations.
The purpose of the testing is twofold: one, to help developers fix any
-problems in their code; two, to provide users with information about
-whether or not a given module works on a given platform.
+problems in their code that crop up because of lack of testing on other
+platforms; two, to provide users with information about whether or not
+a given module works on a given platform.
=over 4
e.g. most of the files in the F<hints/> directory in the source code kit).
On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>,
too) is determined by lowercasing and stripping punctuation from the first
-field of the string returned by typing
-
- % uname -a
-
-(or a similar command) at the shell prompt. Here, for example, are a few
-of the more popular Unix flavors:
+field of the string returned by typing C<uname -a> (or a similar command)
+at the shell prompt. Here, for example, are a few of the more popular
+Unix flavors:
uname $^O $Config{'archname'}
-------------------------------------------
probably better, as it is more consistent with popular usage, and avoids
the problem of remembering what to backwhack and what not to.
-The DOS FAT file system can only accommodate "8.3" style filenames. Under
+The DOS FAT filesystem can only accommodate "8.3" style filenames. Under
the "case insensitive, but case preserving" HPFS (OS/2) and NTFS (NT)
-file systems you may have to be careful about case returned with functions
+filesystems you may have to be careful about case returned with functions
like C<readdir> or used with functions like C<open> or C<opendir>.
DOS also treats several filenames as special, such as AUX, PRN, NUL, CON,
Any module requiring XS compilation is right out for most people, because
MacPerl is built using non-free (and non-cheap!) compilers. Some XS
modules that can work with MacPerl are built and distributed in binary
-form on CPAN. See I<MacPerl: Power and Ease> for more details.
+form on CPAN. See I<MacPerl: Power and Ease> and L<"CPAN Testers">
+for more details.
Directories are specified as:
limited to 31 characters, and may include any character except C<:>,
which is reserved as a path separator.
-Instead of C<flock>, see C<FSpSetFLock> and C<FSpRstFLock> in
-C<Mac::Files>.
+Instead of C<flock>, see C<FSpSetFLock> and C<FSpRstFLock> in the
+C<Mac::Files> module.
In the MacPerl application, you can't run a program from the command line;
programs that expect C<@ARGV> to be populated can be edited with something
perl myscript.plx some arguments
ToolServer is another app from Apple that provides access to MPW tools
-from MPW and the MacPerl app, which allows MacPerl program to use
+from MPW and the MacPerl app, which allows MacPerl programs to use
C<system>, backticks, and piped C<open>.
"S<Mac OS>" is the proper name for the operating system, but the value
$is_ppc = $MacPerl::Architecture eq 'MacPPC';
$is_68k = $MacPerl::Architecture eq 'Mac68K';
-S<Mac OS X>, to be based on NeXT's OpenStep OS, will be able to run MacPerl
-natively (in the Blue Box, and even in the Yellow Box, once some changes
-to the toolbox calls are made), but Unix perl will also run natively.
+S<Mac OS X>, to be based on NeXT's OpenStep OS, will be able to run
+MacPerl natively (in the Blue Box, and even in the Yellow Box, once some
+changes to the toolbox calls are made), but Unix perl will also run
+natively.
Also see:
=head2 VMS
Perl on VMS is discussed in F<vms/perlvms.pod> in the perl distribution.
-Note that perl on VMS can accept either VMS or Unix style file
+Note that perl on VMS can accept either VMS- or Unix-style file
specifications as in either of the following:
$ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
C<readdir> returns lowercased filenames, but specifying a file for
opening remains case insensitive. Files without extensions have a
trailing period on them, so doing a C<readdir> with a file named F<A.;5>
-will return F<a.> (though that file could be opened with C<open(FH, 'A')>.
+will return F<a.> (though that file could be opened with
+C<open(FH, 'A')>).
RMS had an eight level limit on directory depths from any rooted logical
(allowing 16 levels overall) prior to VMS 7.2. Hence
have to take this into account, but at least they can refer to the former
as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
-The C<VMS::Filespec> module, which gets installed as part
-of the build process on VMS, is a pure Perl module that can easily be
-installed on non-VMS platforms and can be helpful for conversions to
-and from RMS native formats.
+The C<VMS::Filespec> module, which gets installed as part of the build
+process on VMS, is a pure Perl module that can easily be installed on
+non-VMS platforms and can be helpful for conversions to and from RMS
+native formats.
What C<\n> represents depends on the type of file that is open. It could
be C<\015>, C<\012>, C<\015\012>, or nothing. Reading from a file
print "Hello from perl!\n";
On these platforms, bear in mind that the EBCDIC character set may have
-an effect on what happens with perl functions such as C<chr>, C<pack>,
-C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>; as well as
-bit-fiddling with ASCII constants using operators like C<^>, C<&> and
-C<|>; not to mention dealing with socket interfaces to ASCII computers
+an effect on what happens with some perl functions (such as C<chr>,
+C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
+well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
+and C<|>, not to mention dealing with socket interfaces to ASCII computers
(see L<"NEWLINES">).
Fortunately, most web servers for the mainframe will correctly translate
the C<\n> in the following statement to its ASCII equivalent (note that
-C<\r> is the same under both ASCII and EBCDIC):
+C<\r> is the same under both Unix and OS/390):
print "Content-type: text/html\r\n\r\n";
if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
Note that one thing you may not want to rely on is the EBCDIC encoding
-of punctuation characters since these may differ from code page to code page
-(and once your module or script is rumoured to work with EBCDIC, folks will
-want it to work with all EBCDIC character sets).
+of punctuation characters since these may differ from code page to code
+page (and once your module or script is rumoured to work with EBCDIC,
+folks will want it to work with all EBCDIC character sets).
Also see:
general usage issues for all EBCDIC Perls. Send a message body of
"subscribe perl-mvs" to majordomo@perl.org.
-=item AS/400 Perl information at C<http://as400.rochester.ibm.com>
+=item AS/400 Perl information at C<http://as400.rochester.ibm.com/>
=back
=head2 Acorn RISC OS
-As Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like Unix
-and Unix filename emulation is turned on by default, it is quite likely that
-most simple scripts will work "out of the box". The native filing system is
-modular, and individual filing systems are free to be case sensitive or
-insensitive, usually case preserving. Some native filing systems have name
-length limits which file and directory names are silently truncated to fit -
-scripts should be aware that the standard disc filing system currently has
-a name length limit of B<10> characters, with up to 77 items in a directory,
-but other filing systems may not impose such limitations.
+As Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
+Unix and Unix filename emulation is turned on by default, it is quite
+likely that most simple scripts will work "out of the box". The native
+filing system is modular, and individual filing systems are free to be
+case-sensitive or insensitive, and are usually case-preserving. Some
+native filing systems have name length limits which file and directory
+names are silently truncated to fit - scripts should be aware that the
+standard disc filing system currently has a name length limit of B<10>
+characters, with up to 77 items in a directory, but other filing systems
+may not impose such limitations.
Native filenames are of the form
The default filename translation is roughly C<tr|/.|./|;>
Note that C<"ADFS::HardDisc.$.File" ne 'ADFS::HardDisc.$.File'> and that
-the second stage of $ interpolation in regular expressions will fall foul
-of the C<$.> if scripts are not careful.
-
-Logical paths specified by system variables containing comma separated
-search lists are also allowed, hence C<System:Modules> is a valid filename,
-and the filesystem will prefix C<Modules> with each section of C<System$Path>
-until a name is made that points to an object on disc. Writing to a new
-file C<System:Modules> would only be allowed if C<System$Path> contains a
-single item list. The filesystem will also expand system variables in
-filenames if enclosed in angle brackets, so C<E<lt>System$DirE<gt>.Modules>
-would look for the file S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious
-implication of this is that B<fully qualified filenames can start with C<E<lt>E<gt>>>
-and should be protected when C<open> is used for input.
+the second stage of C<$> interpolation in regular expressions will fall
+foul of the C<$.> if scripts are not careful.
+
+Logical paths specified by system variables containing comma-separated
+search lists are also allowed, hence C<System:Modules> is a valid
+filename, and the filesystem will prefix C<Modules> with each section of
+C<System$Path> until a name is made that points to an object on disc.
+Writing to a new file C<System:Modules> would only be allowed if
+C<System$Path> contains a single item list. The filesystem will also
+expand system variables in filenames if enclosed in angle brackets, so
+C<E<lt>System$DirE<gt>.Modules> would look for the file
+S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
+that B<fully qualified filenames can start with C<E<lt>E<gt>> and should
+be protected when C<open> is used for input.
Because C<.> was in use as a directory separator and filenames could not
be assumed to be unique after 10 characters, Acorn implemented the C
11charname_.c c.11charname (assuming filesystem truncates at 10)
The Unix emulation library's translation of filenames to native assumes
-that this sort of translation is required, and allows a user defined list of
-known suffixes which it will transpose in this fashion. This may appear
-transparent, but consider that with these rules C<foo/bar/baz.h> and
-C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
-C<glob> cannot and do not attempt to emulate the reverse mapping. Other '.'s
-in filenames are translated to '/'.
-
-S<RISC OS> has "image files", files that behave as directories. For
-example with suitable software this allows the contents of a zip file to
-be treated as a directory at command line (and therefore script) level,
-with full read-write random access. At present the perl port treats images
-as directories: C<-d> returns true, C<-f> false, and C<unlink> checks to
-ensure that recognised images are empty before deleting them. In theory
-images should never trouble a script, but in practice they may do so if
-the software to deal with an image file is loaded and registered while the
-script is running, as suddenly "files" that it had cached information on
-metamorphose into directories.
-
-As implied above the environment accessed through C<%ENV> is global, and the
-convention is that program specific environment variables are of the form
-C<Program$Name>. Each filing system maintains a current directory, and
-the current filing system's current directory is the B<global> current
-directory. Consequently sociable scripts don't change the current directory
-but rely on full pathnames, and scripts (and Makefiles) cannot assume that
-they can spawn a child process which can change the current directory
-without affecting its parent (and everyone else for that matter).
-
-As native operating system filehandles are global and currently are allocated
-down from 255, with 0 being a reserved value the Unix emulation library
-emulates Unix filehandles. Consequently you can't rely on passing C<STDIN>
-C<STDOUT> or C<STDERR> to your children. Run time libraries perform
-command line processing to emulate Unix shell style C<>> redirection, but
-the core operating system is written in assembler and has its own private,
-obscure and somewhat broken convention. All this is further complicated by
-the desire of users to express filenames of the form C<E<lt>Foo$DirE<gt>.Bar> on
-the command line unquoted. (Oh yes, it's run time libraries interpreting the
-quoting convention.) Hence C<``> command output capture has to perform
-a guessing game as to how the command is going to interpret the command line
-so that it can bodge it correctly to capture output. It assumes that a
-string C<E<lt>[^E<lt>E<gt>]+\$[^E<lt>E<gt>]E<gt>> is a reference to an environment
-variable, whereas anything else involving C<E<lt>> or C<E<gt>> is redirection,
-and generally manages to be 99% right. Despite all this the problem remains
-that scripts cannot rely on any Unix tools being available, or that any tools
-found have Unix-like command line arguments.
-
-Extensions and XS are in theory buildable by anyone using free tools. In
-practice many don't as the Acorn platform is used to binary distribution.
-MakeMaker does itself run, but no make currently copes with MakeMaker's
-makefiles! Even if (when) this is fixed os that the lack of a Unix-like
-shell can cause problems with makefile rules, especially lines of the form
-C<cd sdbm && make all> and anything using quoting.
+that this sort of translation is required, and allows a user defined list
+of known suffixes which it will transpose in this fashion. This may
+appear transparent, but consider that with these rules C<foo/bar/baz.h>
+and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
+C<glob> cannot and do not attempt to emulate the reverse mapping. Other
+C<.>s in filenames are translated to C</>.
+
+As implied above the environment accessed through C<%ENV> is global, and
+the convention is that program specific environment variables are of the
+form C<Program$Name>. Each filing system maintains a current directory,
+and the current filing system's current directory is the B<global> current
+directory. Consequently, sociable scripts don't change the current
+directory but rely on full pathnames, and scripts (and Makefiles) cannot
+assume that they can spawn a child process which can change the current
+directory without affecting its parent (and everyone else for that
+matter).
+
+As native operating system filehandles are global and currently are
+allocated down from 255, with 0 being a reserved value the Unix emulation
+library emulates Unix filehandles. Consequently, you can't rely on
+passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
+
+The desire of users to express filenames of the form
+C<E<lt>Foo$DirE<gt>.Bar> on the command line unquoted causes problems,
+too: C<``> command output capture has to perform a guessing game. It
+assumes that a string C<E<lt>[^E<lt>E<gt>]+\$[^E<lt>E<gt>]E<gt>> is a
+reference to an environment variable, whereas anything else involving
+C<E<lt>> or C<E<gt>> is redirection, and generally manages to be 99%
+right. Of course, the problem remains that scripts cannot rely on any
+Unix tools being available, or that any tools found have Unix-like command
+line arguments.
+
+Extensions and XS are, in theory, buildable by anyone using free tools.
+In practice, many don't, as users of the Acorn platform are used to binary
+distribution. MakeMaker does run, but no available make currently copes
+with MakeMaker's makefiles; even if/when this is fixed, the lack of a
+Unix-like shell can cause problems with makefile rules, especially lines
+of the form C<cd sdbm && make all>, and anything using quoting.
"S<RISC OS>" is the proper name for the operating system, but the value
in C<$^O> is "riscos" (because we don't like shouting).
Perl has been ported to a variety of platforms that do not fit into any of
the above categories. Some, such as AmigaOS, BeOS, QNX, and Plan 9, have
-been well integrated into the standard Perl source code kit. You may need
+been well-integrated into the standard Perl source code kit. You may need
to see the F<ports/> directory on CPAN for information, and possibly
-binaries, for the likes of: aos, atari, lynxos, HP-MPE/iX, riscos,
-Tandem Guardian, vos, I<etc.> (yes we know that some of these OSes may fall
-under the Unix category but we are not a standards body.)
+binaries, for the likes of: aos, atari, lynxos, riscos, Tandem Guardian,
+vos, I<etc.> (yes we know that some of these OSes may fall under the Unix
+category, but we are not a standards body.)
See also:
=item Novell Netware
-A free Perl 5 based PERL.NLM for Novell Netware is available from
+A free perl5-based PERL.NLM for Novell Netware is available from
C<http://www.novell.com/>
=back
doubt, consult the platform-specific README files in the Perl source
distribution, and other documentation resources for a given port.
-Be aware, moreover, that even among Unix-ish systems there are variations,
-and not all functions listed here are necessarily available, though
-most usually are.
+Be aware, moreover, that even among Unix-ish systems there are variations.
For many functions, you can also query C<%Config>, exported by default
from C<Config.pm>. For example, to check if the platform has the C<lstat>
-call, check C<$Config{'d_lstat'}>. See L<Config> for a full description
-of available variables.
+call, check C<$Config{'d_lstat'}>. See L<Config.pm> for a full
+description of available variables.
=head2 Alphabetical Listing of Perl Functions
(VMS)
C<-T> and C<-B> are implemented, but might misclassify Mac text files
-with foreign characters; this is the case will all platforms, but
-affects S<Mac OS> a lot. (S<Mac OS>)
+with foreign characters; this is the case will all platforms, but may
+affect S<Mac OS> often. (S<Mac OS>)
C<-x> (or C<-X>) determine if a file ends in one of the executable
suffixes. C<-S> is meaningless. (Win32)
Globbing built-in, but only C<*> and C<?> metacharacters are supported.
(S<Mac OS>)
-Features depend on external perlglob.exe or perlglob.bat. May be overridden
-with something like File::DosGlob, which is recommended. (Win32)
+Features depend on external perlglob.exe or perlglob.bat. May be
+overridden with something like File::DosGlob, which is recommended.
+(Win32)
Globbing built-in, but only C<*> and C<?> metacharacters are supported.
-Globbing relies on operating system calls, which may return filenames in
-any order. As most filesystems are case insensitive even "sorted"
-filenames will not be in case sensitive order. (S<RISC OS>)
+Globbing relies on operating system calls, which may return filenames
+in any order. As most filesystems are case-insensitive, even "sorted"
+filenames will not be in case-sensitive order. (S<RISC OS>)
=item ioctl FILEHANDLE,FUNCTION,SCALAR
=item kill LIST
-Not implemented, hence not useful for taint checking. (S<Mac OS>, S<RISC OS>)
+Not implemented, hence not useful for taint checking. (S<Mac OS>,
+S<RISC OS>)
-Available only for process handles returned by the C<system(1, ...)> method of
-spawning a process. (Win32)
+Available only for process handles returned by the C<system(1, ...)>
+method of spawning a process. (Win32)
=item link OLDFILE,NEWFILE
=item sysopen FILEHANDLE,FILENAME,MODE,PERMS
The traditional "0", "1", and "2" MODEs are implemented with different
-numeric values on some systems. The flags exported by C<Fcntl> should work
-everywhere though. (S<Mac OS>, OS/390)
+numeric values on some systems. The flags exported by C<Fcntl> should
+work everywhere though. (S<Mac OS>, OS/390)
=item system LIST
=over 4
+=item 1.33, 06 August 1998
+
+Integrate more minor changes.
+
=item 1.32, 05 August 1998
Integrate more minor changes.
=head1 VERSION
-Version 1.32, last modified 05 August 1998.
+Version 1.33, last modified 06 August 1998.
+
projects / platform / upstream / perl.git / commitdiff