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  26. <div class="titlepage"><div><div><h3 class="title">
  27. <a name="boost_typetraits.reference.is_pod"></a><a class="link" href="is_pod.html" title="is_pod">is_pod</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_pod</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. POD 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. POD stands for "Plain old data". Arithmetic types, and enumeration
  39. types, a pointers and pointer to members are all PODs. Classes and unions
  40. can also be POD's if they have no non-static data members that are of reference
  41. or non-POD type, no user defined constructors, no user defined assignment
  42. operators, no private or protected non-static data members, no virtual functions
  43. and no base classes. Finally, a cv-qualified POD is still a POD, as is an
  44. array of PODs.
  45. </p>
  46. <p>
  47. <span class="bold"><strong>C++ Standard Reference:</strong></span> 3.9p10 and 9p4 (Note
  48. that POD's are also aggregates, see 8.5.1).
  49. </p>
  50. <p>
  51. <span class="bold"><strong>Compiler Compatibility:</strong></span> Without some (as
  52. yet unspecified) help from the compiler, is_pod will never report that a
  53. class or struct is a POD; this is always safe, if possibly sub-optimal. Currently
  54. (June 2015) compilers more recent than Visual C++ 8, Clang-3, GCC-4.3, Greenhills
  55. 6.0, Intel-11.0, and Codegear have the necessary compiler <a class="link" href="../intrinsics.html" title="Support for Compiler Intrinsics">intrinsics</a>
  56. to ensure that this trait "just works". You may also test to see
  57. if the necessary <a class="link" href="../intrinsics.html" title="Support for Compiler Intrinsics">intrinsics</a>
  58. are available by checking to see if the macro <code class="computeroutput"><span class="identifier">BOOST_IS_POD</span></code>
  59. is defined.
  60. </p>
  61. <p>
  62. <span class="bold"><strong>Header:</strong></span> <code class="computeroutput"> <span class="preprocessor">#include</span>
  63. <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_pod</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
  64. 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>
  65. </p>
  66. <p>
  67. <span class="bold"><strong>Examples:</strong></span>
  68. </p>
  69. <div class="blockquote"><blockquote class="blockquote"><p>
  70. <code class="computeroutput"><span class="identifier">is_pod</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;</span></code>
  71. inherits from <code class="computeroutput"><a class="link" href="integral_constant.html" title="integral_constant">true_type</a></code>.
  72. </p></blockquote></div>
  73. <div class="blockquote"><blockquote class="blockquote"><p>
  74. <code class="computeroutput"><span class="identifier">is_pod</span><span class="special">&lt;</span><span class="keyword">char</span><span class="special">*&gt;::</span><span class="identifier">type</span></code> is the type <code class="computeroutput"><a class="link" href="integral_constant.html" title="integral_constant">true_type</a></code>.
  75. </p></blockquote></div>
  76. <div class="blockquote"><blockquote class="blockquote"><p>
  77. <code class="computeroutput"><span class="identifier">is_pod</span><span class="special">&lt;</span><span class="keyword">int</span> <span class="special">(*)(</span><span class="keyword">long</span><span class="special">)&gt;::</span><span class="identifier">value</span></code> is an integral constant expression
  78. that evaluates to <span class="emphasis"><em>true</em></span>.
  79. </p></blockquote></div>
  80. <div class="blockquote"><blockquote class="blockquote"><p>
  81. <code class="computeroutput"><span class="identifier">is_pod</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
  82. that evaluates to <span class="emphasis"><em>false</em></span>.
  83. </p></blockquote></div>
  84. <div class="blockquote"><blockquote class="blockquote"><p>
  85. <code class="computeroutput"><span class="identifier">is_pod</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>.
  86. </p></blockquote></div>
  87. </div>
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  90. <td align="right"><div class="copyright-footer">Copyright &#169; 2000, 2011 Adobe Systems Inc, David Abrahams,
  91. Frederic Bron, Steve Cleary, Beman Dawes, Aleksey Gurtovoy, Howard Hinnant,
  92. Jesse Jones, Mat Marcus, Itay Maman, John Maddock, Alexander Nasonov, Thorsten
  93. Ottosen, Roman Perepelitsa, Robert Ramey, Jeremy Siek, Robert Stewart and Steven
  94. Watanabe<p>
  95. Distributed under the Boost Software License, Version 1.0. (See accompanying
  96. file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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