ceph/src/boost/libs/mpl/doc/refmanual/sizeof.html

   1 <?xml version="1.0" encoding="utf-8" ?>
   2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
   3 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
   4 <head>
   5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
   6 <meta name="generator" content="Docutils 0.7: http://docutils.sourceforge.net/" />
   7 <title>The MPL Reference Manual: sizeof_</title>
   8 <link rel="stylesheet" href="../style.css" type="text/css" />
   9 </head>
  10 <body class="docframe refmanual">
  11 <table class="header"><tr class="header"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./max.html" class="navigation-link">Prev</a>&nbsp;<a href="./data-types.html" class="navigation-link">Next</a></span><span class="navigation-group-separator">&nbsp;|&nbsp;</span><span class="navigation-group"><a href="./max.html" class="navigation-link">Back</a>&nbsp;Along</span><span class="navigation-group-separator">&nbsp;|&nbsp;</span><span class="navigation-group"><a href="./miscellaneous.html" class="navigation-link">Up</a>&nbsp;<a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator">&nbsp;|&nbsp;</span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td>
  12 <td class="header-group page-location"><a href="../refmanual.html" class="navigation-link">Front Page</a> / <a href="./metafunctions.html" class="navigation-link">Metafunctions</a> / <a href="./miscellaneous.html" class="navigation-link">Miscellaneous</a> / <a href="./sizeof.html" class="navigation-link">sizeof_</a></td>
  13 </tr></table><div class="header-separator"></div>
  14 <div class="section" id="sizeof">
  15 <h1><a class="toc-backref" href="./miscellaneous.html#id1571">sizeof_</a></h1>
  16 <div class="section" id="id1207">
  17 <h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3>
  18 <pre class="literal-block">
  19 template&lt;
  20       typename X
  21     &gt;
  22 struct <a href="./sizeof.html" class="identifier">sizeof_</a>
  23 {
  24     typedef <em>unspecified</em> type;
  25 };
  26 </pre>
  27 </div>
  28 <div class="section" id="id1208">
  29 <h3><a class="subsection-title" href="#description" name="description">Description</a></h3>
  30 <p>Returns the result of a <tt class="literal"><span class="pre">sizeof(X)</span></tt> expression wrapped into an
  31 <a class="reference internal" href="./integral-constant.html">Integral Constant</a> of the corresponding type, <tt class="literal"><span class="pre">std::<a href="./size-t.html" class="identifier">size_t</a></span></tt>.</p>
  32 </div>
  33 <div class="section" id="id1209">
  34 <h3><a class="subsection-title" href="#header" name="header">Header</a></h3>
  35 <pre class="literal-block">
  36 #include &lt;<a href="../../../../boost/mpl/sizeof.hpp" class="header">boost/mpl/sizeof.hpp</a>&gt;
  37 </pre>
  38 </div>
  39 <div class="section" id="id1210">
  40 <h3><a class="subsection-title" href="#model-of" name="model-of">Model of</a></h3>
  41 <p><a class="reference internal" href="./metafunction.html">Metafunction</a></p>
  42 </div>
  43 <div class="section" id="id1211">
  44 <h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3>
  45 <table border="1" class="docutils table">
  46 <colgroup>
  47 <col width="19%" />
  48 <col width="25%" />
  49 <col width="56%" />
  50 </colgroup>
  51 <thead valign="bottom">
  52 <tr><th class="head">Parameter</th>
  53 <th class="head">Requirement</th>
  54 <th class="head">Description</th>
  55 </tr>
  56 </thead>
  57 <tbody valign="top">
  58 <tr><td><tt class="literal"><span class="pre">X</span></tt></td>
  59 <td>Any type</td>
  60 <td>A type to compute the <tt class="literal"><span class="pre">sizeof</span></tt> for.</td>
  61 </tr>
  62 </tbody>
  63 </table>
  64 </div>
  65 <div class="section" id="id1212">
  66 <h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3>
  67 <p>For an arbitrary type <tt class="literal"><span class="pre">x</span></tt>:</p>
  68 <pre class="literal-block">
  69 typedef <a href="./sizeof.html" class="identifier">sizeof_</a>&lt;x&gt;::type n;
  70 </pre>
  71 <table class="docutils field-list" frame="void" rules="none">
  72 <col class="field-name" />
  73 <col class="field-body" />
  74 <tbody valign="top">
  75 <tr class="field"><th class="field-name">Return type:</th><td class="field-body"><p class="first"><a class="reference internal" href="./integral-constant.html">Integral Constant</a>.</p>
  76 </td>
  77 </tr>
  78 <tr class="field"><th class="field-name">Precondition:</th><td class="field-body"><p class="first"><tt class="literal"><span class="pre">x</span></tt> is a complete type.</p>
  79 </td>
  80 </tr>
  81 <tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><p class="first">Equivalent to</p>
  82 <pre class="last literal-block">
  83 typedef <a href="./size-t.html" class="identifier">size_t</a>&lt; sizeof(x) &gt; n;
  84 </pre>
  85 </td>
  86 </tr>
  87 </tbody>
  88 </table>
  89 </div>
  90 <div class="section" id="id1213">
  91 <h3><a class="subsection-title" href="#complexity" name="complexity">Complexity</a></h3>
  92 <p>Constant time.</p>
  93 </div>
  94 <div class="section" id="id1214">
  95 <h3><a class="subsection-title" href="#example" name="example">Example</a></h3>
  96 <pre class="literal-block">
  97 struct udt { char a[100]; };
  98
  99 <a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( <a href="./sizeof.html" class="identifier">sizeof_</a>&lt;char&gt;::value, ==, sizeof(char) );
 100 <a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( <a href="./sizeof.html" class="identifier">sizeof_</a>&lt;int&gt;::value, ==, sizeof(int) );
 101 <a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( <a href="./sizeof.html" class="identifier">sizeof_</a>&lt;double&gt;::value, ==, sizeof(double) );
 102 <a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( <a href="./sizeof.html" class="identifier">sizeof_</a>&lt;udt&gt;::value, ==, sizeof(my) );
 103 </pre>
 104 </div>
 105 <div class="section" id="id1215">
 106 <h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3>
 107 <p><a class="reference internal" href="./metafunctions.html">Metafunctions</a>, <a class="reference internal" href="./integral-constant.html">Integral Constant</a>, <a class="reference internal" href="./size-t.html">size_t</a></p>
 108 </div>
 109 </div>
 110
 111 <div class="footer-separator"></div>
 112 <table class="footer"><tr class="footer"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./max.html" class="navigation-link">Prev</a>&nbsp;<a href="./data-types.html" class="navigation-link">Next</a></span><span class="navigation-group-separator">&nbsp;|&nbsp;</span><span class="navigation-group"><a href="./max.html" class="navigation-link">Back</a>&nbsp;Along</span><span class="navigation-group-separator">&nbsp;|&nbsp;</span><span class="navigation-group"><a href="./miscellaneous.html" class="navigation-link">Up</a>&nbsp;<a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator">&nbsp;|&nbsp;</span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td>
 113 <td><div class="copyright-footer"><div class="copyright">Copyright ©  2001-2009 Aleksey Gurtovoy and David Abrahams</div>
 114 Distributed under the Boost Software License, Version 1.0. (See accompanying
 115 file LICENSE_1_0.txt or copy at <a class="reference external" href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)</div></td></tr></table></body>
 116 </html>