ceph/src/boost/libs/type_traits/doc/html/boost_typetraits/reference/promote.html

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  26 <div class="titlepage"><div><div><h3 class="title">
  27 <a name="boost_typetraits.reference.promote"></a><a class="link" href="promote.html" title="promote">promote</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">promote</span>
  31 <span class="special">{</span>
  32    <span class="keyword">typedef</span> <em class="replaceable"><code>see-below</code></em> <span class="identifier">type</span><span class="special">;</span>
  33 <span class="special">};</span>
  34 </pre>
  35 <p>
  36         <span class="bold"><strong>type:</strong></span> If integral or floating point promotion
  37         can be applied to an rvalue of type <code class="computeroutput"><span class="identifier">T</span></code>,
  38         then applies integral and floating point promotions to <code class="computeroutput"><span class="identifier">T</span></code>
  39         and keeps cv-qualifiers of <code class="computeroutput"><span class="identifier">T</span></code>,
  40         otherwise leaves <code class="computeroutput"><span class="identifier">T</span></code> unchanged.
  41         See also <a class="link" href="integral_promotion.html" title="integral_promotion">integral_promotion</a>
  42         and <a class="link" href="floating_point_promotion.html" title="floating_point_promotion">floating_point_promotion</a>.
  43       </p>
  44 <p>
  45         <span class="bold"><strong>C++ Standard Reference:</strong></span> 4.5 except 4.5/3
  46         (integral bit-field) and 4.6.
  47       </p>
  48 <p>
  49         <span class="bold"><strong>Compiler Compatibility:</strong></span> All current compilers
  50         are supported by this trait.
  51       </p>
  52 <p>
  53         <span class="bold"><strong>Header:</strong></span> <code class="computeroutput"> <span class="preprocessor">#include</span>
  54         <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">promote</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
  55         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>
  56       </p>
  57 <div class="table">
  58 <a name="boost_typetraits.reference.promote.examples"></a><p class="title"><b>Table&#160;1.25.&#160;Examples</b></p>
  59 <div class="table-contents"><table class="table" summary="Examples">
  60 <colgroup>
  61 <col>
  62 <col>
  63 </colgroup>
  64 <thead><tr>
  65 <th>
  66                 <p>
  67                   Expression
  68                 </p>
  69               </th>
  70 <th>
  71                 <p>
  72                   Result Type
  73                 </p>
  74               </th>
  75 </tr></thead>
  76 <tbody>
  77 <tr>
  78 <td>
  79                 <p>
  80                   <code class="computeroutput"><span class="identifier">promote</span><span class="special">&lt;</span><span class="keyword">short</span> <span class="keyword">volatile</span><span class="special">&gt;::</span><span class="identifier">type</span></code>
  81                 </p>
  82               </td>
  83 <td>
  84                 <p>
  85                   <code class="computeroutput"><span class="keyword">int</span> <span class="keyword">volatile</span></code>
  86                 </p>
  87               </td>
  88 </tr>
  89 <tr>
  90 <td>
  91                 <p>
  92                   <code class="computeroutput"><span class="identifier">promote</span><span class="special">&lt;</span><span class="keyword">float</span> <span class="keyword">const</span><span class="special">&gt;::</span><span class="identifier">type</span></code>
  93                 </p>
  94               </td>
  95 <td>
  96                 <p>
  97                   <code class="computeroutput"><span class="keyword">double</span> <span class="keyword">const</span></code>
  98                 </p>
  99               </td>
 100 </tr>
 101 <tr>
 102 <td>
 103                 <p>
 104                   <code class="computeroutput"><span class="identifier">promote</span><span class="special">&lt;</span><span class="keyword">short</span><span class="special">&amp;&gt;::</span><span class="identifier">type</span></code>
 105                 </p>
 106               </td>
 107 <td>
 108                 <p>
 109                   <code class="computeroutput"><span class="keyword">short</span><span class="special">&amp;</span></code>
 110                 </p>
 111               </td>
 112 </tr>
 113 </tbody>
 114 </table></div>
 115 </div>
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