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| <div class="toc"><dl class="toc"><dt><span class="section"><a href="is_same.html#core.is_same.header_boost_core_is_same_hpp">Header <boost/core/is_same.hpp></a></span></dt></dl></div> |
| <div class="simplesect"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="idp86502640"></a>Authors</h3></div></div></div> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| Peter Dimov |
| </li></ul></div> |
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| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="core.is_same.header_boost_core_is_same_hpp"></a><a class="link" href="is_same.html#core.is_same.header_boost_core_is_same_hpp" title="Header <boost/core/is_same.hpp>">Header <boost/core/is_same.hpp></a> |
| </h3></div></div></div> |
| <p> |
| The header <code class="computeroutput"><span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">core</span><span class="special">/</span><span class="identifier">is_same</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> |
| defines the class template <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">core</span><span class="special">::</span><span class="identifier">is_same</span><span class="special"><</span><span class="identifier">T1</span><span class="special">,</span><span class="identifier">T2</span><span class="special">></span></code>. |
| It defines a nested integral constant <code class="computeroutput"><span class="identifier">value</span></code> |
| which is <code class="computeroutput"><span class="keyword">true</span></code> when <code class="computeroutput"><span class="identifier">T1</span></code> and <code class="computeroutput"><span class="identifier">T2</span></code> |
| are the same type, and <code class="computeroutput"><span class="keyword">false</span></code> |
| when they are not. |
| </p> |
| <p> |
| In tandem with <code class="computeroutput"><span class="identifier">BOOST_TEST_TRAIT_TRUE</span></code> |
| and <code class="computeroutput"><span class="identifier">BOOST_TEST_TRAIT_FALSE</span></code>, |
| <code class="computeroutput"><span class="identifier">is_same</span></code> is useful for writing |
| tests for traits classes that have to define specific nested types. |
| </p> |
| <div class="section"> |
| <div class="titlepage"><div><div><h4 class="title"> |
| <a name="core.is_same.header_boost_core_is_same_hpp.synopsis"></a><a class="link" href="is_same.html#core.is_same.header_boost_core_is_same_hpp.synopsis" title="Synopsis">Synopsis</a> |
| </h4></div></div></div> |
| <pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span> |
| <span class="special">{</span> |
| |
| <span class="keyword">namespace</span> <span class="identifier">core</span> |
| <span class="special">{</span> |
| <span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">T1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">T2</span><span class="special">></span> <span class="keyword">struct</span> <span class="identifier">is_same</span><span class="special">;</span> |
| <span class="special">}</span> |
| |
| <span class="special">}</span> |
| </pre> |
| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h4 class="title"> |
| <a name="core.is_same.header_boost_core_is_same_hpp.example"></a><a class="link" href="is_same.html#core.is_same.header_boost_core_is_same_hpp.example" title="Example">Example</a> |
| </h4></div></div></div> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">core</span><span class="special">/</span><span class="identifier">lightweight_test_trait</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">core</span><span class="special">/</span><span class="identifier">is_same</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| |
| <span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> <span class="keyword">struct</span> <span class="identifier">X</span> |
| <span class="special">{</span> |
| <span class="keyword">typedef</span> <span class="identifier">T</span><span class="special">&</span> <span class="identifier">type</span><span class="special">;</span> |
| <span class="special">};</span> |
| |
| <span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">core</span><span class="special">::</span><span class="identifier">is_same</span><span class="special">;</span> |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="identifier">BOOST_TEST_TRAIT_TRUE</span><span class="special">((</span> <span class="identifier">is_same</span><span class="special"><</span><span class="identifier">X</span><span class="special"><</span><span class="keyword">int</span><span class="special">>::</span><span class="identifier">type</span><span class="special">,</span> <span class="keyword">int</span><span class="special">&></span> <span class="special">));</span> |
| <span class="keyword">return</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">report_errors</span><span class="special">();</span> |
| <span class="special">}</span> |
| </pre> |
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| <td align="right"><div class="copyright-footer">Copyright © 2014 Peter Dimov<br>Copyright © 2014 Glen Fernandes<br>Copyright © 2014 Andrey Semashev<p> |
| Distributed under the <a href="http://boost.org/LICENSE_1_0.txt" target="_top">Boost |
| Software License, Version 1.0</a>. |
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