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  26 <div class="titlepage"><div><div><h3 class="title">
  27 <a name="boost_typetraits.reference.is_class"></a><a class="link" href="is_class.html" title="is_class">is_class</a>
  28 </h3></div></div></div>
  29 <pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span>
  30 <span class="keyword">struct</span> <span class="identifier">is_class</span> <span class="special">:</span> <span class="keyword">public</span> <em class="replaceable"><code><a class="link" href="integral_constant.html" title="integral_constant">true_type</a>-or-<a class="link" href="integral_constant.html" title="integral_constant">false_type</a></code></em> <span class="special">{};</span>
  31 </pre>
  32 <p>
  33         <span class="bold"><strong>Inherits:</strong></span> If T is a (possibly cv-qualified)
  34         class type (and not a union type) then inherits from <a class="link" href="integral_constant.html" title="integral_constant">true_type</a>,
  35         otherwise inherits from <a class="link" href="integral_constant.html" title="integral_constant">false_type</a>.
  36       </p>
  37 <p>
  38         <span class="bold"><strong>C++ Standard Reference:</strong></span> 3.9.2 and 9.2.
  39       </p>
  40 <p>
  41         <span class="bold"><strong>Header:</strong></span> <code class="computeroutput"> <span class="preprocessor">#include</span>
  42         <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">type_traits</span><span class="special">/</span><span class="identifier">is_class</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
  43         or <code class="computeroutput"> <span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">type_traits</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
  44       </p>
  45 <p>
  46         <span class="bold"><strong>Compiler Compatibility:</strong></span> This trait works
  47         correctly for almost all current compilers (as of June 2015), with just a
  48         minority of older compilers not correctly detecting all the corner cases.
  49         You can check the macro <code class="computeroutput"><span class="identifier">BOOST_TT_HAS_CONFORMING_IS_CLASS_IMPLEMENTATION</span></code>
  50         which is defined to 1 when the class works correctly in all cases.
  51       </p>
  52 <p>
  53         <span class="bold"><strong>Examples:</strong></span>
  54       </p>
  55 <div class="blockquote"><blockquote class="blockquote"><p>
  56           Given: <code class="computeroutput"><span class="keyword">class</span> <span class="identifier">MyClass</span><span class="special">;</span></code> then:
  57         </p></blockquote></div>
  58 <div class="blockquote"><blockquote class="blockquote"><p>
  59           <code class="computeroutput"><span class="identifier">is_class</span><span class="special">&lt;</span><span class="identifier">MyClass</span><span class="special">&gt;</span></code>
  60           inherits from <code class="computeroutput"><a class="link" href="integral_constant.html" title="integral_constant">true_type</a></code>.
  61         </p></blockquote></div>
  62 <div class="blockquote"><blockquote class="blockquote"><p>
  63           <code class="computeroutput"><span class="identifier">is_class</span><span class="special">&lt;</span><span class="identifier">MyClass</span> <span class="keyword">const</span><span class="special">&gt;::</span><span class="identifier">type</span></code>
  64           is the type <code class="computeroutput"><a class="link" href="integral_constant.html" title="integral_constant">true_type</a></code>.
  65         </p></blockquote></div>
  66 <div class="blockquote"><blockquote class="blockquote"><p>
  67           <code class="computeroutput"><span class="identifier">is_class</span><span class="special">&lt;</span><span class="identifier">MyClass</span><span class="special">&gt;::</span><span class="identifier">value</span></code> is an integral constant expression
  68           that evaluates to <span class="emphasis"><em>true</em></span>.
  69         </p></blockquote></div>
  70 <div class="blockquote"><blockquote class="blockquote"><p>
  71           <code class="computeroutput"><span class="identifier">is_class</span><span class="special">&lt;</span><span class="identifier">MyClass</span><span class="special">&amp;&gt;::</span><span class="identifier">value</span></code> is an integral constant expression
  72           that evaluates to <span class="emphasis"><em>false</em></span>.
  73         </p></blockquote></div>
  74 <div class="blockquote"><blockquote class="blockquote"><p>
  75           <code class="computeroutput"><span class="identifier">is_class</span><span class="special">&lt;</span><span class="identifier">MyClass</span><span class="special">*&gt;::</span><span class="identifier">value</span></code> is an integral constant expression
  76           that evaluates to <span class="emphasis"><em>false</em></span>.
  77         </p></blockquote></div>
  78 <div class="blockquote"><blockquote class="blockquote"><p>
  79           <code class="computeroutput"><span class="identifier">is_class</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;::</span><span class="identifier">value_type</span></code> is the type <code class="computeroutput"><span class="keyword">bool</span></code>.
  80         </p></blockquote></div>
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