1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 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 1. Boost.Core"> 8<link rel="up" href="../core/ref.html#header.boost.core.ref_hpp" title="Header <boost/core/ref.hpp>"> 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 — 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: <<a class="link" href="../core/ref.html#header.boost.core.ref_hpp" title="Header <boost/core/ref.hpp>">boost/core/ref.hpp</a>> 33 34</span><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></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#idm45442566544128-bb"><span class="identifier">reference_wrapper</span></a><span class="special">(</span><span class="identifier">T</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 42 <a class="link" href="reference_wrapper.html#idm45442566540560-bb"><span class="identifier">reference_wrapper</span></a><span class="special">(</span><span class="identifier">T</span> <span class="special">&&</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#idm45442566552672-bb">public member functions</a></span> 45 <a class="link" href="reference_wrapper.html#idm45442566552112-bb"><span class="keyword">operator</span> <span class="identifier">T</span> <span class="special">&</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">&</span> <a class="link" href="reference_wrapper.html#idm45442566549552-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#idm45442566546816-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="idm45312826407648"></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&</code>, which usually allows the function templates to work on references unmodified. </p> 52<div class="refsect2"> 53<a name="idm45312826405056"></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="idm45312826398464"></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="idm45442566544128-bb"></a><span class="identifier">reference_wrapper</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&</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="idm45442566540560-bb"></a><span class="identifier">reference_wrapper</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&&</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="idm45312826380512"></a><h3> 88<a name="idm45442566552672-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="idm45442566552112-bb"></a><span class="keyword">operator</span> <span class="identifier">T</span> <span class="special">&</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">&</span> <a name="idm45442566549552-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="idm45442566546816-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 © 2014 Peter Dimov<br>Copyright © 2014 Glen Fernandes<br>Copyright © 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> 165
