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| <div class="section" id="boost-mpl-has-xxx-trait-def"> |
| <h1><a class="toc-backref" href="./introspection.html#id1595">BOOST_MPL_HAS_XXX_TRAIT_DEF</a></h1> |
| <div class="section" id="id1329"> |
| <h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3> |
| <pre class="literal-block"> |
| #define <a href="./has-xxx-trait-def.html" class="identifier">BOOST_MPL_HAS_XXX_TRAIT_DEF</a>(name) \ |
| <em>unspecified token sequence</em> \ |
| /**/ |
| </pre> |
| </div> |
| <div class="section" id="id1330"> |
| <h3><a class="subsection-title" href="#description" name="description">Description</a></h3> |
| <p>Expands into a definition of a boolean unary <a class="reference internal" href="./metafunction.html">Metafunction</a> <tt class="literal"><span class="pre">has_name</span></tt> |
| such that for any type <tt class="literal"><span class="pre">x</span></tt> <tt class="literal"><span class="pre">has_name<x>::value</span> <span class="pre">==</span> <span class="pre">true</span></tt> if and only |
| if <tt class="literal"><span class="pre">x</span></tt> is a class type and has a nested type memeber <tt class="literal"><span class="pre">x::name</span></tt>.</p> |
| <p>On the deficient compilers not capabale of performing the detection, |
| <tt class="literal"><span class="pre">has_name<x>::value</span></tt> always returns <tt class="literal"><span class="pre">false</span></tt>. A boolean configuraion |
| macro, <a class="reference internal" href="./cfg-no-has-xxx.html">BOOST_MPL_CFG_NO_HAS_XXX</a>, is provided to signal or override |
| the "deficient" status of a particular compiler.</p> |
| <p>[<em>Note:</em> <a class="reference internal" href="./has-xxx-trait-def.html">BOOST_MPL_HAS_XXX_TRAIT_DEF</a> is a simplified front end to |
| the <a class="reference internal" href="./has-xxx-trait-named-def.html">BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF</a> introspection macro — <em>end note</em>]</p> |
| </div> |
| <div class="section" id="id1331"> |
| <h3><a class="subsection-title" href="#header" name="header">Header</a></h3> |
| <pre class="literal-block"> |
| #include <<a href="../../../../boost/mpl/has_xxx.hpp" class="header">boost/mpl/has_xxx.hpp</a>> |
| </pre> |
| </div> |
| <div class="section" id="id1332"> |
| <h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3> |
| <table border="1" class="docutils table"> |
| <colgroup> |
| <col width="15%" /> |
| <col width="32%" /> |
| <col width="53%" /> |
| </colgroup> |
| <thead valign="bottom"> |
| <tr><th class="head">Parameter</th> |
| <th class="head">Requirement</th> |
| <th class="head">Description</th> |
| </tr> |
| </thead> |
| <tbody valign="top"> |
| <tr><td><tt class="literal"><span class="pre">name</span></tt></td> |
| <td>A legal identifier token</td> |
| <td>A name of the member being detected.</td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| <div class="section" id="id1333"> |
| <h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> |
| <p>For any legal C++ identifier <tt class="literal"><span class="pre">name</span></tt>:</p> |
| <pre class="literal-block"> |
| <a href="./has-xxx-trait-def.html" class="identifier">BOOST_MPL_HAS_XXX_TRAIT_DEF</a>(name) |
| </pre> |
| <table class="docutils field-list" frame="void" rules="none"> |
| <col class="field-name" /> |
| <col class="field-body" /> |
| <tbody valign="top"> |
| <tr class="field"><th class="field-name">Precondition:</th><td class="field-body"><p class="first">Appears at namespace scope.</p> |
| </td> |
| </tr> |
| <tr class="field"><th class="field-name">Return type:</th><td class="field-body"><p class="first">None.</p> |
| </td> |
| </tr> |
| <tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><p class="first">Equivalent to</p> |
| <pre class="last literal-block"> |
| <a href="./has-xxx-trait-named-def.html" class="identifier">BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF</a>( |
| BOOST_PP_CAT(has_,name), name, false |
| ) |
| </pre> |
| </td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| <div class="section" id="id1334"> |
| <h3><a class="subsection-title" href="#example" name="example">Example</a></h3> |
| <pre class="literal-block"> |
| <a href="./has-xxx-trait-def.html" class="identifier">BOOST_MPL_HAS_XXX_TRAIT_DEF</a>(xxx) |
| |
| struct test1 {}; |
| struct test2 { void xxx(); }; |
| struct test3 { int xxx; }; |
| struct test4 { static int xxx(); }; |
| struct test5 { template< typename T > struct xxx {}; }; |
| struct test6 { typedef int xxx; }; |
| struct test7 { struct xxx; }; |
| struct test8 { typedef void (*xxx)(); }; |
| struct test9 { typedef void (xxx)(); }; |
| |
| <a href="./assert-not.html" class="identifier">BOOST_MPL_ASSERT_NOT</a>(( has_xxx<test1> )); |
| <a href="./assert-not.html" class="identifier">BOOST_MPL_ASSERT_NOT</a>(( has_xxx<test2> )); |
| <a href="./assert-not.html" class="identifier">BOOST_MPL_ASSERT_NOT</a>(( has_xxx<test3> )); |
| <a href="./assert-not.html" class="identifier">BOOST_MPL_ASSERT_NOT</a>(( has_xxx<test4> )); |
| <a href="./assert-not.html" class="identifier">BOOST_MPL_ASSERT_NOT</a>(( has_xxx<test5> )); |
| |
| #if !defined(<a href="./cfg-no-has-xxx.html" class="identifier">BOOST_MPL_CFG_NO_HAS_XXX</a>) |
| <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( has_xxx<test6> )); |
| <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( has_xxx<test7> )); |
| <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( has_xxx<test8> )); |
| <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( has_xxx<test9> )); |
| #endif |
| |
| <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( has_xxx<test6,<a href="./bool.html" class="identifier">true_</a>> )); |
| <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( has_xxx<test7,<a href="./bool.html" class="identifier">true_</a>> )); |
| <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( has_xxx<test8,<a href="./bool.html" class="identifier">true_</a>> )); |
| <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( has_xxx<test9,<a href="./bool.html" class="identifier">true_</a>> )); |
| </pre> |
| </div> |
| <div class="section" id="id1335"> |
| <h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> |
| <p><a class="reference internal" href="./macros.html">Macros</a>, <a class="reference internal" href="./has-xxx-trait-named-def.html">BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF</a>, <a class="reference internal" href="./cfg-no-has-xxx.html">BOOST_MPL_CFG_NO_HAS_XXX</a></p> |
| <!-- Macros/Introspection//BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF --> |
| </div> |
| </div> |
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