libs/core/doc/html/boost/reference_wrapper.html

   1 <html>
   2 <head>
   3 <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
   4 <title>Class template reference_wrapper</title>
   5 <link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css">
   6 <meta name="generator" content="DocBook XSL Stylesheets V1.79.1">
   7 <link rel="home" href="../index.html" title="Chapter&#160;1.&#160;Boost.Core">
   8 <link rel="up" href="../core/ref.html#header.boost.core.ref_hpp" title="Header &lt;boost/core/ref.hpp&gt;">
   9 <link rel="prev" href="is_reference_wrapper.html" title="Struct template is_reference_wrapper">
  10 <link rel="next" href="unwrap_reference.html" title="Struct template unwrap_reference">
  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="is_reference_wrapper.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../core/ref.html#header.boost.core.ref_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="unwrap_reference.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
  24 </div>
  25 <div class="refentry">
  26 <a name="boost.reference_wrapper"></a><div class="titlepage"></div>
  27 <div class="refnamediv">
  28 <h2><span class="refentrytitle">Class template reference_wrapper</span></h2>
  29 <p>boost::reference_wrapper &#8212; Contains a reference to an object of type <code class="computeroutput">T</code>. </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="../core/ref.html#header.boost.core.ref_hpp" title="Header &lt;boost/core/ref.hpp&gt;">boost/core/ref.hpp</a>&gt;
  33
  34 </span><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> T<span class="special">&gt;</span>
  35 <span class="keyword">class</span> <a class="link" href="reference_wrapper.html" title="Class template reference_wrapper">reference_wrapper</a> <span class="special">{</span>
  36 <span class="keyword">public</span><span class="special">:</span>
  37   <span class="comment">// <a class="link" href="reference_wrapper.html#boost.reference_wrappertypes">types</a></span>
  38   <span class="keyword">typedef</span> <span class="identifier">T</span> <a class="link" href="reference_wrapper.html#boost.reference_wrapper.type"><span class="identifier">type</span></a><span class="special">;</span>
  39
  40   <span class="comment">// <a class="link" href="reference_wrapper.html#boost.reference_wrapperconstruct-copy-destruct">construct/copy/destruct</a></span>
  41   <span class="keyword">explicit</span> <a class="link" href="reference_wrapper.html#idm45818739695344-bb"><span class="identifier">reference_wrapper</span></a><span class="special">(</span><span class="identifier">T</span> <span class="special">&amp;</span><span class="special">)</span><span class="special">;</span>
  42   <a class="link" href="reference_wrapper.html#idm45818739691824-bb"><span class="identifier">reference_wrapper</span></a><span class="special">(</span><span class="identifier">T</span> <span class="special">&amp;&amp;</span><span class="special">)</span> <span class="special">=</span> <span class="keyword">delete</span><span class="special">;</span>
  43
  44   <span class="comment">// <a class="link" href="reference_wrapper.html#idm45818732268720-bb">public member functions</a></span>
  45   <a class="link" href="reference_wrapper.html#idm45818732268160-bb"><span class="keyword">operator</span> <span class="identifier">T</span> <span class="special">&amp;</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
  46   <span class="identifier">T</span> <span class="special">&amp;</span> <a class="link" href="reference_wrapper.html#idm45818732265600-bb"><span class="identifier">get</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
  47   <span class="identifier">T</span> <span class="special">*</span> <a class="link" href="reference_wrapper.html#idm45818739698032-bb"><span class="identifier">get_pointer</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
  48 <span class="special">}</span><span class="special">;</span></pre></div>
  49 <div class="refsect1">
  50 <a name="idm46687073625248"></a><h2>Description</h2>
  51 <p><code class="computeroutput"><a class="link" href="reference_wrapper.html" title="Class template reference_wrapper">reference_wrapper</a></code> is primarily used to "feed" references to function templates (algorithms) that take their parameter by value. It provides an implicit conversion to <code class="computeroutput">T&amp;</code>, which usually allows the function templates to work on references unmodified. </p>
  52 <div class="refsect2">
  53 <a name="idm46687073622656"></a><h3>
  54 <a name="boost.reference_wrappertypes"></a><code class="computeroutput">reference_wrapper</code>
  55         public
  56        types</h3>
  57 <div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
  58 <p>
  59 <span class="keyword">typedef</span> <span class="identifier">T</span> <a name="boost.reference_wrapper.type"></a><span class="identifier">type</span><span class="special">;</span></p>
  60 <p>Type <code class="computeroutput">T</code>. </p>
  61 </li></ol></div>
  62 </div>
  63 <div class="refsect2">
  64 <a name="idm46687073616064"></a><h3>
  65 <a name="boost.reference_wrapperconstruct-copy-destruct"></a><code class="computeroutput">reference_wrapper</code>
  66         public
  67        construct/copy/destruct</h3>
  68 <div class="orderedlist"><ol class="orderedlist" type="1">
  69 <li class="listitem">
  70 <pre class="literallayout"><span class="keyword">explicit</span> <a name="idm45818739695344-bb"></a><span class="identifier">reference_wrapper</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&amp;</span> t<span class="special">)</span><span class="special">;</span></pre>
  71 <p>Constructs a <code class="computeroutput"><code class="computeroutput"><a class="link" href="reference_wrapper.html" title="Class template reference_wrapper">reference_wrapper</a></code></code> object that stores a reference to <code class="computeroutput">t</code>.</p>
  72 <p>Does not throw. </p>
  73 <p>
  74
  75 </p>
  76 </li>
  77 <li class="listitem">
  78 <pre class="literallayout"><a name="idm45818739691824-bb"></a><span class="identifier">reference_wrapper</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&amp;&amp;</span> t<span class="special">)</span> <span class="special">=</span> <span class="keyword">delete</span><span class="special">;</span></pre>
  79 <p>Construction from a temporary object is disabled. </p>
  80 <p>
  81
  82 </p>
  83 </li>
  84 </ol></div>
  85 </div>
  86 <div class="refsect2">
  87 <a name="idm46687073598192"></a><h3>
  88 <a name="idm45818732268720-bb"></a><code class="computeroutput">reference_wrapper</code> public member functions</h3>
  89 <div class="orderedlist"><ol class="orderedlist" type="1">
  90 <li class="listitem">
  91 <pre class="literallayout"><a name="idm45818732268160-bb"></a><span class="keyword">operator</span> <span class="identifier">T</span> <span class="special">&amp;</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
  92 <p>
  93 </p>
  94 <p>Does not throw. </p>
  95 <p>
  96
  97 </p>
  98 <div class="variablelist"><table border="0" class="variablelist compact">
  99 <colgroup>
 100 <col align="left" valign="top">
 101 <col>
 102 </colgroup>
 103 <tbody><tr>
 104 <td><p><span class="term">Returns:</span></p></td>
 105 <td><p>The stored reference. </p></td>
 106 </tr></tbody>
 107 </table></div>
 108 </li>
 109 <li class="listitem">
 110 <pre class="literallayout"><span class="identifier">T</span> <span class="special">&amp;</span> <a name="idm45818732265600-bb"></a><span class="identifier">get</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
 111 <p>
 112 </p>
 113 <p>Does not throw. </p>
 114 <p>
 115
 116 </p>
 117 <div class="variablelist"><table border="0" class="variablelist compact">
 118 <colgroup>
 119 <col align="left" valign="top">
 120 <col>
 121 </colgroup>
 122 <tbody><tr>
 123 <td><p><span class="term">Returns:</span></p></td>
 124 <td><p>The stored reference. </p></td>
 125 </tr></tbody>
 126 </table></div>
 127 </li>
 128 <li class="listitem">
 129 <pre class="literallayout"><span class="identifier">T</span> <span class="special">*</span> <a name="idm45818739698032-bb"></a><span class="identifier">get_pointer</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
 130 <p>
 131 </p>
 132 <p>Does not throw. </p>
 133 <p>
 134
 135 </p>
 136 <div class="variablelist"><table border="0" class="variablelist compact">
 137 <colgroup>
 138 <col align="left" valign="top">
 139 <col>
 140 </colgroup>
 141 <tbody><tr>
 142 <td><p><span class="term">Returns:</span></p></td>
 143 <td><p>A pointer to the object referenced by the stored reference. </p></td>
 144 </tr></tbody>
 145 </table></div>
 146 </li>
 147 </ol></div>
 148 </div>
 149 </div>
 150 </div>
 151 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 152 <td align="left"></td>
 153 <td align="right"><div class="copyright-footer">Copyright &#169; 2014 Peter Dimov<br>Copyright &#169; 2014 Glen Fernandes<br>Copyright &#169; 2014 Andrey Semashev<p>
 154         Distributed under the <a href="http://boost.org/LICENSE_1_0.txt" target="_top">Boost
 155         Software License, Version 1.0</a>.
 156       </p>
 157 </div></td>
 158 </tr></table>
 159 <hr>
 160 <div class="spirit-nav">
 161 <a accesskey="p" href="is_reference_wrapper.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../core/ref.html#header.boost.core.ref_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="unwrap_reference.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
 162 </div>
 163 </body>
 164 </html>