doc/html/boost/signalN.html

   1 <html>
   2 <head>
   3 <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
   4 <title>Class template signalN</title>
   5 <link rel="stylesheet" href="../../../doc/src/boostbook.css" type="text/css">
   6 <meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
   7 <link rel="home" href="../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset">
   8 <link rel="up" href="../signals/reference.html#header.boost.signal_hpp" title="Header &lt;boost/signal.hpp&gt;">
   9 <link rel="prev" href="../signals/reference.html" title="Reference">
  10 <link rel="next" href="signal.html" title="Class template signal">
  11 </head>
  12 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
  13 <table cellpadding="2" width="100%"><tr>
  14 <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../boost.png"></td>
  15 <td align="center"><a href="../../../index.html">Home</a></td>
  16 <td align="center"><a href="../../../libs/libraries.htm">Libraries</a></td>
  17 <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
  18 <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
  19 <td align="center"><a href="../../../more/index.htm">More</a></td>
  20 </tr></table>
  21 <hr>
  22 <div class="spirit-nav">
  23 <a accesskey="p" href="../signals/reference.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../signals/reference.html#header.boost.signal_hpp"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="signal.html"><img src="../../../doc/src/images/next.png" alt="Next"></a>
  24 </div>
  25 <div class="refentry">
  26 <a name="boost.signalN"></a><div class="titlepage"></div>
  27 <div class="refnamediv">
  28 <h2><span class="refentrytitle">Class template signalN</span></h2>
  29 <p>boost::signalN &#8212; Set of safe multicast callback types.</p>
  30 </div>
  31 <h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
  32 <div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="../signals/reference.html#header.boost.signal_hpp" title="Header &lt;boost/signal.hpp&gt;">boost/signal.hpp</a>&gt;
  33
  34 </span><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> R<span class="special">,</span> <span class="keyword">typename</span> T1<span class="special">,</span> <span class="keyword">typename</span> T2<span class="special">,</span> <span class="special">...</span><span class="special">,</span> <span class="keyword">typename</span> TN<span class="special">,</span>
  35          <span class="keyword">typename</span> Combiner <span class="special">=</span> <a class="link" href="last_value.html" title="Class template last_value">last_value</a><span class="special">&lt;</span><span class="identifier">R</span><span class="special">&gt;</span><span class="special">,</span> <span class="keyword">typename</span> Group <span class="special">=</span> <span class="keyword">int</span><span class="special">,</span>
  36          <span class="keyword">typename</span> GroupCompare <span class="special">=</span> std::less<span class="special">&lt;</span><span class="identifier">Group</span><span class="special">&gt;</span><span class="special">,</span>
  37          <span class="keyword">typename</span> SlotFunction <span class="special">=</span> <a class="link" href="functionN.html" title="Class template functionN">functionN</a><span class="special">&lt;</span><span class="identifier">R</span><span class="special">,</span> <span class="identifier">T1</span><span class="special">,</span> <span class="identifier">T2</span><span class="special">,</span> <span class="special">...</span><span class="special">,</span> <span class="identifier">TN</span><span class="special">&gt;</span> <span class="special">&gt;</span>
  38 <span class="keyword">class</span> <a class="link" href="signalN.html" title="Class template signalN">signalN</a> <span class="special">:</span> <span class="keyword">public</span> <a class="link" href="signals/trackable.html" title="Class trackable">signals::trackable</a>,
  39                 <span class="keyword">private</span> noncopyable   <span class="comment">// Exposition only</span>
  40 <span class="special">{</span>
  41 <span class="keyword">public</span><span class="special">:</span>
  42   <span class="comment">// types</span>
  43   <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">Combiner</span><span class="special">::</span><span class="identifier">result_type</span> <a name="boost.signalN.result_type"></a><span class="identifier">result_type</span><span class="special">;</span>
  44   <span class="keyword">typedef</span> <span class="identifier">Combiner</span>                       <a name="boost.signalN.combiner_type"></a><span class="identifier">combiner_type</span><span class="special">;</span>
  45   <span class="keyword">typedef</span> <span class="identifier">Group</span>                          <a name="boost.signalN.group_type"></a><span class="identifier">group_type</span><span class="special">;</span>
  46   <span class="keyword">typedef</span> <span class="identifier">GroupCompare</span>                   <a name="boost.signalN.group_compare_type"></a><span class="identifier">group_compare_type</span><span class="special">;</span>
  47   <span class="keyword">typedef</span> <span class="identifier">SlotFunction</span>                   <a name="boost.signalN.slot_function_type"></a><span class="identifier">slot_function_type</span><span class="special">;</span>
  48   <span class="keyword">typedef</span> <a class="link" href="slot.html" title="Class template slot">slot</a><span class="special">&lt;</span><span class="identifier">SlotFunction</span><span class="special">&gt;</span>             <a name="boost.signalN.slot_type"></a><span class="identifier">slot_type</span><span class="special">;</span>
  49   <span class="keyword">typedef</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span>                    <a name="boost.signalN.slot_result_type"></a><span class="identifier">slot_result_type</span><span class="special">;</span>
  50   <span class="keyword">typedef</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span>                    <a name="boost.signalN.slot_call_iterator"></a><span class="identifier">slot_call_iterator</span><span class="special">;</span>
  51   <span class="keyword">typedef</span> <span class="identifier">T1</span>                             <a name="boost.signalN.argument_type"></a><span class="identifier">argument_type</span><span class="special">;</span>         <span class="comment">// If N == 1</span>
  52   <span class="keyword">typedef</span> <span class="identifier">T1</span>                             <a name="boost.signalN.first_argument_type"></a><span class="identifier">first_argument_type</span><span class="special">;</span>   <span class="comment">// If N == 2</span>
  53   <span class="keyword">typedef</span> <span class="identifier">T2</span>                             <a name="boost.signalN.second_argument_type"></a><span class="identifier">second_argument_type</span><span class="special">;</span>  <span class="comment">// If N == 2</span>
  54   <span class="keyword">typedef</span> <span class="identifier">T1</span>                             <a name="boost.signalN.arg1_type"></a><span class="identifier">arg1_type</span><span class="special">;</span>
  55   <span class="keyword">typedef</span> <span class="identifier">T2</span>                             <a name="boost.signalN.arg2_type"></a><span class="identifier">arg2_type</span><span class="special">;</span>
  56      .
  57      .
  58      .
  59   <span class="keyword">typedef</span> <span class="identifier">TN</span>                             <a name="boost.signalN.argN_type"></a><span class="identifier">argN_type</span><span class="special">;</span>
  60
  61   <span class="comment">// static constants</span>
  62   <span class="keyword">static</span> <span class="keyword">const</span> <span class="keyword">int</span> <span class="identifier">arity</span> = <span class="identifier">N</span><span class="special">;</span>
  63
  64   <span class="comment">// <a class="link" href="signalN.html#boost.signalNconstruct-copy-destruct">construct/copy/destruct</a></span>
  65   <a class="link" href="signalN.html#idp113907664-bb"><span class="identifier">signalN</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">combiner_type</span><span class="special">&amp;</span> <span class="special">=</span> <span class="identifier">combiner_type</span><span class="special">(</span><span class="special">)</span><span class="special">,</span>
  66           <span class="keyword">const</span> <span class="identifier">group_compare_type</span><span class="special">&amp;</span> <span class="special">=</span> <span class="identifier">group_compare_type</span><span class="special">(</span><span class="special">)</span><span class="special">)</span><span class="special">;</span>
  67   <a class="link" href="signalN.html#idp220493664-bb"><span class="special">~</span><span class="identifier">signalN</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span>
  68
  69   <span class="comment">// <a class="link" href="signalN.html#idp146239744-bb">connection management</a></span>
  70   <a class="link" href="signals/connection.html" title="Class connection">signals::connection</a>
  71   <a class="link" href="signalN.html#idp156506464-bb"><span class="identifier">connect</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">slot_type</span><span class="special">&amp;</span><span class="special">,</span> <span class="identifier">signals</span><span class="special">::</span><span class="identifier">connect_position</span> <span class="special">=</span> <span class="identifier">signals</span><span class="special">::</span><span class="identifier">at_back</span><span class="special">)</span><span class="special">;</span>
  72   <a class="link" href="signals/connection.html" title="Class connection">signals::connection</a>
  73   <a class="link" href="signalN.html#idp152667584-bb"><span class="identifier">connect</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">group_type</span><span class="special">&amp;</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">slot_type</span><span class="special">&amp;</span><span class="special">,</span>
  74           <span class="identifier">signals</span><span class="special">::</span><span class="identifier">connect_position</span> <span class="special">=</span> <span class="identifier">signals</span><span class="special">::</span><span class="identifier">at_back</span><span class="special">)</span><span class="special">;</span>
  75   <span class="keyword">void</span> <a class="link" href="signalN.html#idp106476320-bb"><span class="identifier">disconnect</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">group_type</span><span class="special">&amp;</span><span class="special">)</span><span class="special">;</span>
  76   <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Slot<span class="special">&gt;</span> <span class="keyword">void</span> <a class="link" href="signalN.html#idp105604496-bb"><span class="identifier">disconnect</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">Slot</span><span class="special">&amp;</span><span class="special">)</span><span class="special">;</span>
  77   <span class="keyword">void</span> <a class="link" href="signalN.html#idp73510928-bb"><span class="identifier">disconnect_all_slots</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span>
  78   <span class="keyword">bool</span> <a class="link" href="signalN.html#idp40245408-bb"><span class="identifier">empty</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
  79   <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <a class="link" href="signalN.html#idp40336976-bb"><span class="identifier">num_slots</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
  80
  81   <span class="comment">// <a class="link" href="signalN.html#idp94164336-bb">invocation</a></span>
  82   <span class="identifier">result_type</span> <a class="link" href="signalN.html#idp153544144-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="identifier">arg1_type</span><span class="special">,</span> <span class="identifier">arg2_type</span><span class="special">,</span> <span class="special">...</span><span class="special">,</span> <span class="identifier">argN_type</span><span class="special">)</span><span class="special">;</span>
  83   <span class="identifier">result_type</span> <a class="link" href="signalN.html#idp155242112-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="identifier">arg1_type</span><span class="special">,</span> <span class="identifier">arg2_type</span><span class="special">,</span> <span class="special">...</span><span class="special">,</span> <span class="identifier">argN_type</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
  84
  85   <span class="comment">// <a class="link" href="signalN.html#idp151149424-bb">combiner access</a></span>
  86   <span class="identifier">combiner_type</span><span class="special">&amp;</span> <a class="link" href="signalN.html#idp106449008-bb"><span class="identifier">combiner</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span>
  87   <span class="keyword">const</span> <span class="identifier">combiner_type</span><span class="special">&amp;</span> <a class="link" href="signalN.html#idp106449904-bb"><span class="identifier">combiner</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
  88 <span class="special">}</span><span class="special">;</span></pre></div>
  89 <div class="refsect1">
  90 <a name="idp425669792"></a><h2>Description</h2>
  91 <p>The class template <a class="link" href="signalN.html" title="Class template signalN">signalN</a> covers
  92          several related classes signal0, signal1, signal2, etc.,
  93          where the number suffix describes the number of function
  94          parameters the signal and its connected slots will
  95          take. Instead of enumerating all classes, a single pattern
  96          <a class="link" href="signalN.html" title="Class template signalN">signalN</a> will be described, where N
  97          represents the number of function parameters.</p>
  98 <div class="refsect2">
  99 <a name="idp425672736"></a><h3>
 100 <a name="boost.signalNconstruct-copy-destruct"></a><code class="computeroutput">signalN</code>
 101         public
 102        construct/copy/destruct</h3>
 103 <div class="orderedlist"><ol class="orderedlist" type="1">
 104 <li class="listitem">
 105 <pre class="literallayout"><a name="idp113907664-bb"></a><span class="identifier">signalN</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">combiner_type</span><span class="special">&amp;</span> combiner <span class="special">=</span> <span class="identifier">combiner_type</span><span class="special">(</span><span class="special">)</span><span class="special">,</span>
 106         <span class="keyword">const</span> <span class="identifier">group_compare_type</span><span class="special">&amp;</span> compare <span class="special">=</span> <span class="identifier">group_compare_type</span><span class="special">(</span><span class="special">)</span><span class="special">)</span><span class="special">;</span></pre>
 107 <div class="variablelist"><table border="0" class="variablelist compact">
 108 <colgroup>
 109 <col align="left" valign="top">
 110 <col>
 111 </colgroup>
 112 <tbody>
 113 <tr>
 114 <td><p><span class="term">Effects:</span></p></td>
 115 <td>Initializes the signal to contain no slots, copies the given combiner into internal storage, and stores the given group comparison function object to compare groups.</td>
 116 </tr>
 117 <tr>
 118 <td><p><span class="term">Postconditions:</span></p></td>
 119 <td><code class="computeroutput">this-&gt;<a class="link" href="signalN.html#idp40245408-bb">empty</a>()</code></td>
 120 </tr>
 121 </tbody>
 122 </table></div>
 123 </li>
 124 <li class="listitem">
 125 <pre class="literallayout"><a name="idp220493664-bb"></a><span class="special">~</span><span class="identifier">signalN</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre>
 126 <div class="variablelist"><table border="0" class="variablelist compact">
 127 <colgroup>
 128 <col align="left" valign="top">
 129 <col>
 130 </colgroup>
 131 <tbody><tr>
 132 <td><p><span class="term">Effects:</span></p></td>
 133 <td>Disconnects all slots connected to <code class="computeroutput">*this</code>.</td>
 134 </tr></tbody>
 135 </table></div>
 136 </li>
 137 </ol></div>
 138 </div>
 139 <div class="refsect2">
 140 <a name="idp425697440"></a><h3>
 141 <a name="idp146239744-bb"></a><code class="computeroutput">signalN</code> connection management</h3>
 142 <div class="orderedlist"><ol class="orderedlist" type="1">
 143 <li class="listitem">
 144 <pre class="literallayout"><a name="idp146240304-bb"></a><a class="link" href="signals/connection.html" title="Class connection">signals::connection</a>
 145 <a name="idp156506464-bb"></a><span class="identifier">connect</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">slot_type</span><span class="special">&amp;</span> slot<span class="special">,</span>
 146         <span class="identifier">signals</span><span class="special">::</span><span class="identifier">connect_position</span> at <span class="special">=</span> <span class="identifier">signals</span><span class="special">::</span><span class="identifier">at_back</span><span class="special">)</span><span class="special">;</span>
 147 <a class="link" href="signals/connection.html" title="Class connection">signals::connection</a>
 148 <a name="idp152667584-bb"></a><span class="identifier">connect</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">group_type</span><span class="special">&amp;</span> group<span class="special">,</span> <span class="keyword">const</span> <span class="identifier">slot_type</span><span class="special">&amp;</span> slot<span class="special">,</span>
 149         <span class="identifier">signals</span><span class="special">::</span><span class="identifier">connect_position</span> at <span class="special">=</span> <span class="identifier">signals</span><span class="special">::</span><span class="identifier">at_back</span><span class="special">)</span><span class="special">;</span></pre>
 150 <div class="variablelist"><table border="0" class="variablelist compact">
 151 <colgroup>
 152 <col align="left" valign="top">
 153 <col>
 154 </colgroup>
 155 <tbody>
 156 <tr>
 157 <td><p><span class="term">Effects:</span></p></td>
 158 <td>Connects the signal this to the incoming
 159           slot. If the slot is inactive, i.e., any of the trackable
 160           objects bound by the slot call have been destroyed, then the
 161           call to connect is a no-op. If the second version of
 162           <code class="computeroutput">connect</code> is invoked, the
 163           slot is associated with the given group. The <code class="computeroutput">at</code>
 164           parameter specifies where the slot should be connected:
 165           <code class="computeroutput">at_front</code> indicates that the slot will be
 166           connected at the front of the list or group of slots and
 167           <code class="computeroutput">at_back</code> indicates that the slot will be
 168           connected at the back of the list or group of
 169           slots.</td>
 170 </tr>
 171 <tr>
 172 <td><p><span class="term">Returns:</span></p></td>
 173 <td>A
 174           <code class="computeroutput"><a class="link" href="signals/connection.html" title="Class connection">signals::connection</a></code>
 175           object that references the newly-created connection between
 176           the signal and the slot; if the slot is inactive, returns a
 177           disconnected connection.</td>
 178 </tr>
 179 <tr>
 180 <td><p><span class="term">Throws:</span></p></td>
 181 <td>This routine meets the strong exception guarantee,
 182           where any exception thrown will cause the slot to not be
 183           connected to the signal.</td>
 184 </tr>
 185 <tr>
 186 <td><p><span class="term">Complexity:</span></p></td>
 187 <td>Constant time when connecting a slot
 188           without a group name or logarithmic in the number of groups
 189           when connecting to a particular
 190           group.</td>
 191 </tr>
 192 <tr>
 193 <td><p><span class="term">Notes:</span></p></td>
 194 <td>It is unspecified whether connecting a slot while the
 195           signal is calling will result in the slot being called
 196           immediately.</td>
 197 </tr>
 198 </tbody>
 199 </table></div>
 200 </li>
 201 <li class="listitem">
 202 <pre class="literallayout"><a name="idp211498240-bb"></a><span class="keyword">void</span> <a name="idp106476320-bb"></a><span class="identifier">disconnect</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">group_type</span><span class="special">&amp;</span> group<span class="special">)</span><span class="special">;</span>
 203 <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Slot<span class="special">&gt;</span> <span class="keyword">void</span> <a name="idp105604496-bb"></a><span class="identifier">disconnect</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">Slot</span><span class="special">&amp;</span> slot<span class="special">)</span><span class="special">;</span></pre>
 204 <div class="variablelist"><table border="0" class="variablelist compact">
 205 <colgroup>
 206 <col align="left" valign="top">
 207 <col>
 208 </colgroup>
 209 <tbody>
 210 <tr>
 211 <td><p><span class="term">Effects:</span></p></td>
 212 <td>If the parameter is (convertible to) a
 213           group name, any slots in the given group are
 214           disconnected. Otherwise, any slots equal to the given slot
 215           are disconnected.</td>
 216 </tr>
 217 <tr>
 218 <td><p><span class="term">Throws:</span></p></td>
 219 <td>Will not throw unless a user destructor or
 220           equality operator <code class="computeroutput">==</code> throws. If either throws,
 221           not all slots may be disconnected.</td>
 222 </tr>
 223 <tr>
 224 <td><p><span class="term">Complexity:</span></p></td>
 225 <td>If a group is given, O(lg g) + k where
 226           g is the number of groups in the signal and k is the
 227           number of slots in the group. Otherwise, linear in the
 228           number of slots connected to the
 229           signal.</td>
 230 </tr>
 231 </tbody>
 232 </table></div>
 233 </li>
 234 <li class="listitem">
 235 <pre class="literallayout"><span class="keyword">void</span> <a name="idp73510928-bb"></a><span class="identifier">disconnect_all_slots</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre>
 236 <div class="variablelist"><table border="0" class="variablelist compact">
 237 <colgroup>
 238 <col align="left" valign="top">
 239 <col>
 240 </colgroup>
 241 <tbody>
 242 <tr>
 243 <td><p><span class="term">Effects:</span></p></td>
 244 <td>Disconnects all slots connected to the signal.</td>
 245 </tr>
 246 <tr>
 247 <td><p><span class="term">Postconditions:</span></p></td>
 248 <td>
 249 <code class="computeroutput">this-&gt;<a class="link" href="signalN.html#idp40245408-bb">empty</a>()</code>.</td>
 250 </tr>
 251 <tr>
 252 <td><p><span class="term">Throws:</span></p></td>
 253 <td>If disconnecting a slot causes an exception to be
 254           thrown, not all slots may be disconnected.</td>
 255 </tr>
 256 <tr>
 257 <td><p><span class="term">Complexity:</span></p></td>
 258 <td>Linear in the number of slots known to the
 259           signal.</td>
 260 </tr>
 261 <tr>
 262 <td><p><span class="term">Notes:</span></p></td>
 263 <td>May be called at any time within the lifetime of the
 264           signal, including during calls to the signal's slots.</td>
 265 </tr>
 266 </tbody>
 267 </table></div>
 268 </li>
 269 <li class="listitem">
 270 <pre class="literallayout"><span class="keyword">bool</span> <a name="idp40245408-bb"></a><span class="identifier">empty</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
 271 <div class="variablelist"><table border="0" class="variablelist compact">
 272 <colgroup>
 273 <col align="left" valign="top">
 274 <col>
 275 </colgroup>
 276 <tbody>
 277 <tr>
 278 <td><p><span class="term">Returns:</span></p></td>
 279 <td>
 280 <code class="computeroutput">true</code> if no slots
 281           are connected to the signal, and
 282           <code class="computeroutput">false</code> otherwise.</td>
 283 </tr>
 284 <tr>
 285 <td><p><span class="term">Throws:</span></p></td>
 286 <td>Will not throw.</td>
 287 </tr>
 288 <tr>
 289 <td><p><span class="term">Complexity:</span></p></td>
 290 <td>Linear in the number of slots known to the
 291           signal.</td>
 292 </tr>
 293 <tr>
 294 <td><p><span class="term">Rationale:</span></p></td>
 295 <td>Slots can disconnect at any point in time,
 296           including while those same slots are being invoked. It is
 297           therefore possible that the implementation must search
 298           through a list of disconnected slots to determine if any
 299           slots are still connected.</td>
 300 </tr>
 301 </tbody>
 302 </table></div>
 303 </li>
 304 <li class="listitem">
 305 <pre class="literallayout"><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <a name="idp40336976-bb"></a><span class="identifier">num_slots</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
 306 <div class="variablelist"><table border="0" class="variablelist compact">
 307 <colgroup>
 308 <col align="left" valign="top">
 309 <col>
 310 </colgroup>
 311 <tbody>
 312 <tr>
 313 <td><p><span class="term">Returns:</span></p></td>
 314 <td>The number of slots connected to the signal</td>
 315 </tr>
 316 <tr>
 317 <td><p><span class="term">Throws:</span></p></td>
 318 <td>Will not throw.</td>
 319 </tr>
 320 <tr>
 321 <td><p><span class="term">Complexity:</span></p></td>
 322 <td>Linear in the number of slots known to the
 323           signal.</td>
 324 </tr>
 325 <tr>
 326 <td><p><span class="term">Rationale:</span></p></td>
 327 <td>Slots can disconnect at any point in time,
 328           including while those same slots are being invoked. It is
 329           therefore possible that the implementation must search
 330           through a list of disconnected slots to determine how many
 331           slots are still connected.</td>
 332 </tr>
 333 </tbody>
 334 </table></div>
 335 </li>
 336 </ol></div>
 337 </div>
 338 <div class="refsect2">
 339 <a name="idp425784816"></a><h3>
 340 <a name="idp94164336-bb"></a><code class="computeroutput">signalN</code> invocation</h3>
 341 <div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
 342 <pre class="literallayout"><a name="idp94164896-bb"></a><span class="identifier">result_type</span> <a name="idp153544144-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="identifier">arg1_type</span> a1<span class="special">,</span> <span class="identifier">arg2_type</span> a2<span class="special">,</span> <span class="special">...</span><span class="special">,</span> <span class="identifier">argN_type</span> aN<span class="special">)</span><span class="special">;</span>
 343 <span class="identifier">result_type</span> <a name="idp155242112-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="identifier">arg1_type</span> a1<span class="special">,</span> <span class="identifier">arg2_type</span> a2<span class="special">,</span> <span class="special">...</span><span class="special">,</span> <span class="identifier">argN_type</span> aN<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
 344 <div class="variablelist"><table border="0" class="variablelist compact">
 345 <colgroup>
 346 <col align="left" valign="top">
 347 <col>
 348 </colgroup>
 349 <tbody>
 350 <tr>
 351 <td><p><span class="term">Effects:</span></p></td>
 352 <td>Invokes the combiner with a
 353           <code class="computeroutput">slot_call_iterator</code> range
 354           [first, last) corresponding to the sequence of calls to the
 355           slots connected to signal
 356           <code class="computeroutput">*this</code>. Dereferencing an
 357           iterator in this range causes a slot call with the given set
 358           of parameters <code class="computeroutput">(a1, a2, ...,
 359           aN)</code>, the result of which is returned from
 360           the iterator dereference operation.</td>
 361 </tr>
 362 <tr>
 363 <td><p><span class="term">Returns:</span></p></td>
 364 <td>The result returned by the combiner.</td>
 365 </tr>
 366 <tr>
 367 <td><p><span class="term">Throws:</span></p></td>
 368 <td>If an exception is thrown by a slot call, or if the
 369           combiner does not dereference any slot past some given slot,
 370           all slots after that slot in the internal list of connected
 371           slots will not be invoked.</td>
 372 </tr>
 373 <tr>
 374 <td><p><span class="term">Notes:</span></p></td>
 375 <td>
 376 <p class="simpara">Only the slots associated with iterators that are
 377           actually dereferenced will be invoked. Multiple dereferences
 378           of the same iterator will not result in multiple slot
 379           invocations, because the return value of the slot will be
 380           cached.</p>
 381 <p class="simpara">The <code class="computeroutput">const</code> version of
 382           the function call operator will invoke the combiner as
 383           <code class="computeroutput">const</code>, whereas the
 384           non-<code class="computeroutput">const</code> version will
 385           invoke the combiner as
 386           non-<code class="computeroutput">const</code>.</p>
 387 <p class="simpara">Calling the function call operator may invoke undefined
 388           behavior if no slots are connected to the signal, depending
 389           on the combiner used. The default combiner is well-defined
 390           for zero slots when the return type is void but is undefined
 391           when the return type is any other type (because there is no
 392           way to synthesize a return value).</p>
 393 </td>
 394 </tr>
 395 </tbody>
 396 </table></div>
 397 </li></ol></div>
 398 </div>
 399 <div class="refsect2">
 400 <a name="idp425817920"></a><h3>
 401 <a name="idp151149424-bb"></a><code class="computeroutput">signalN</code> combiner access</h3>
 402 <div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
 403 <pre class="literallayout"><a name="idp105174864-bb"></a><span class="identifier">combiner_type</span><span class="special">&amp;</span> <a name="idp106449008-bb"></a><span class="identifier">combiner</span><span class="special">(</span><span class="special">)</span><span class="special">;</span>
 404 <span class="keyword">const</span> <span class="identifier">combiner_type</span><span class="special">&amp;</span> <a name="idp106449904-bb"></a><span class="identifier">combiner</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
 405 <div class="variablelist"><table border="0" class="variablelist compact">
 406 <colgroup>
 407 <col align="left" valign="top">
 408 <col>
 409 </colgroup>
 410 <tbody>
 411 <tr>
 412 <td><p><span class="term">Returns:</span></p></td>
 413 <td>A reference to the stored combiner.</td>
 414 </tr>
 415 <tr>
 416 <td><p><span class="term">Throws:</span></p></td>
 417 <td>Will not throw.</td>
 418 </tr>
 419 </tbody>
 420 </table></div>
 421 </li></ol></div>
 422 </div>
 423 </div>
 424 </div>
 425 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 426 <td align="left"></td>
 427 <td align="right"><div class="copyright-footer">Copyright &#169; 2001-2004 Douglas Gregor<p>Use, modification and distribution is subject to the Boost
 428     Software License, Version 1.0. (See accompanying file
 429     <code class="filename">LICENSE_1_0.txt</code> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)</p>
 430 </div></td>
 431 </tr></table>
 432 <hr>
 433 <div class="spirit-nav">
 434 <a accesskey="p" href="../signals/reference.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../signals/reference.html#header.boost.signal_hpp"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="signal.html"><img src="../../../doc/src/images/next.png" alt="Next"></a>
 435 </div>
 436 </body>
 437 </html>