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<h2><span class="refentrytitle">Class template reference_wrapper</span></h2>
<p>boost::reference_wrapper &#8212;
Contains a reference to an object of type
<code class="computeroutput">T</code>.
</p>
</div>
<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<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="../ref/reference.html#header.boost.ref_hpp" title="Header &lt;boost/ref.hpp&gt;">boost/ref.hpp</a>&gt;
</span><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> T<span class="special">&gt;</span>
<span class="keyword">class</span> <a class="link" href="reference_wrapper.html" title="Class template reference_wrapper">reference_wrapper</a> <span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="comment">// types</span>
<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>
<span class="comment">// <a class="link" href="reference_wrapper.html#boost.reference_wrapperconstruct-copy-destruct">construct/copy/destruct</a></span>
<span class="keyword">explicit</span> <a class="link" href="reference_wrapper.html#id1138547-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>
<span class="comment">// <a class="link" href="reference_wrapper.html#id1138578-bb">access</a></span>
<a class="link" href="reference_wrapper.html#id1138581-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>
<span class="identifier">T</span><span class="special">&amp;</span> <a class="link" href="reference_wrapper.html#id1138598-bb"><span class="identifier">get</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
<span class="identifier">T</span><span class="special">*</span> <a class="link" href="reference_wrapper.html#id1138615-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>
<span class="special">}</span><span class="special">;</span>
<span class="comment">// <a class="link" href="reference_wrapper.html#id1138634-bb">constructors</a></span>
<span class="identifier">reference_wrapper</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <a class="link" href="reference_wrapper.html#boost.reference_wrapper.ref_id1138637"><span class="identifier">ref</span></a><span class="special">(</span><span class="identifier">T</span><span class="special">&amp;</span><span class="special">)</span><span class="special">;</span>
<span class="identifier">reference_wrapper</span><span class="special">&lt;</span><span class="identifier">T</span> <span class="keyword">const</span><span class="special">&gt;</span> <a class="link" href="reference_wrapper.html#boost.reference_wrapper.cref_id1138665"><span class="identifier">cref</span></a><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span><span class="special">)</span><span class="special">;</span>
<span class="comment">// <a class="link" href="reference_wrapper.html#id1138694-bb">access</a></span>
<span class="identifier">unwrap_reference</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span><span class="special">::</span><span class="identifier">type</span><span class="special">&amp;</span> <a class="link" href="reference_wrapper.html#boost.reference_wrapper.unwrap_ref"><span class="identifier">unwrap_ref</span></a><span class="special">(</span><span class="identifier">T</span><span class="special">&amp;</span><span class="special">)</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="id2523665"></a><h2>Description</h2>
<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>
<div class="refsect2">
<a name="id2523693"></a><h3>
<a name="boost.reference_wrapperconstruct-copy-destruct"></a><code class="computeroutput">reference_wrapper</code>
public
construct/copy/destruct</h3>
<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
<pre class="literallayout"><span class="keyword">explicit</span> <a name="id1138547-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>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term">Effects:</span></p></td>
<td>Constructs a
<code class="computeroutput"><a class="link" href="reference_wrapper.html" title="Class template reference_wrapper">reference_wrapper</a></code>
object that stores a reference to
<code class="computeroutput">t</code>.</td>
</tr>
<tr>
<td><p><span class="term">Throws:</span></p></td>
<td>Does not throw.</td>
</tr>
</tbody>
</table></div>
</li></ol></div>
</div>
<div class="refsect2">
<a name="id2523794"></a><h3>
<a name="id1138578-bb"></a><code class="computeroutput">reference_wrapper</code> access</h3>
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">
<pre class="literallayout"><a name="id1138581-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>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td>The stored reference.</td>
</tr>
<tr>
<td><p><span class="term">Throws:</span></p></td>
<td>Does not throw.</td>
</tr>
</tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="identifier">T</span><span class="special">&amp;</span> <a name="id1138598-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>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td>The stored reference.</td>
</tr>
<tr>
<td><p><span class="term">Throws:</span></p></td>
<td>Does not throw.</td>
</tr>
</tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="identifier">T</span><span class="special">*</span> <a name="id1138615-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>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td>A pointer to the object referenced by the stored reference.</td>
</tr>
<tr>
<td><p><span class="term">Throws:</span></p></td>
<td>Does not throw.</td>
</tr>
</tbody>
</table></div>
</li>
</ol></div>
</div>
<div class="refsect2">
<a name="id2524004"></a><h3>
<a name="id1138634-bb"></a><code class="computeroutput">reference_wrapper</code> constructors</h3>
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">
<pre class="literallayout"><span class="identifier">reference_wrapper</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <a name="boost.reference_wrapper.ref_id1138637"></a><span class="identifier">ref</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>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td><code class="computeroutput"><a class="link" href="reference_wrapper.html" title="Class template reference_wrapper">reference_wrapper</a>&lt;T&gt;(t)</code></td>
</tr>
<tr>
<td><p><span class="term">Throws:</span></p></td>
<td>Does not throw.</td>
</tr>
</tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="identifier">reference_wrapper</span><span class="special">&lt;</span><span class="identifier">T</span> <span class="keyword">const</span><span class="special">&gt;</span> <a name="boost.reference_wrapper.cref_id1138665"></a><span class="identifier">cref</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span><span class="special">&amp;</span> t<span class="special">)</span><span class="special">;</span></pre>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td><code class="computeroutput"><a class="link" href="reference_wrapper.html" title="Class template reference_wrapper">reference_wrapper</a>&lt;T const&gt;(t)</code></td>
</tr>
<tr>
<td><p><span class="term">Throws:</span></p></td>
<td>Does not throw.</td>
</tr>
</tbody>
</table></div>
</li>
</ol></div>
</div>
<div class="refsect2">
<a name="id2524208"></a><h3>
<a name="id1138694-bb"></a><code class="computeroutput">reference_wrapper</code> access</h3>
<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
<pre class="literallayout"><span class="identifier">unwrap_reference</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span><span class="special">::</span><span class="identifier">type</span><span class="special">&amp;</span> <a name="boost.reference_wrapper.unwrap_ref"></a><span class="identifier">unwrap_ref</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>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td><code class="computeroutput"><a class="link" href="unwrap_reference.html" title="Class template unwrap_reference">unwrap_reference</a>&lt;T&gt;::type&amp;(t)</code></td>
</tr>
<tr>
<td><p><span class="term">Throws:</span></p></td>
<td>Does not throw.</td>
</tr>
</tbody>
</table></div>
</li></ol></div>
</div>
</div>
</div>
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<td align="left"></td>
<td align="right"><div class="copyright-footer">Copyright &#169; 1999, 2000 Jaakko J&#228;rvi<br>Copyright &#169; 2001, 2002 Peter Dimov<br>Copyright &#169; 2002 David Abrahams<p>Subject to the Boost Software License, Version 1.0. See
accompanying file <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>
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