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| <div class="section" id="boost-mpl-assert"> |
| <h1><a class="toc-backref" href="./asserts.html#id1588">BOOST_MPL_ASSERT</a></h1> |
| <div class="section" id="id1287"> |
| <h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3> |
| <pre class="literal-block"> |
| #define <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>( pred ) \ |
| <em>unspecified token sequence</em> \ |
| /**/ |
| </pre> |
| </div> |
| <div class="section" id="id1288"> |
| <h3><a class="subsection-title" href="#description" name="description">Description</a></h3> |
| <p>Generates a compilation error when the predicate <tt class="literal"><span class="pre">pred</span></tt> holds false.</p> |
| </div> |
| <div class="section" id="id1289"> |
| <h3><a class="subsection-title" href="#header" name="header">Header</a></h3> |
| <pre class="literal-block"> |
| #include <<a href="../../../../boost/mpl/assert.hpp" class="header">boost/mpl/assert.hpp</a>> |
| </pre> |
| </div> |
| <div class="section" id="id1290"> |
| <h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3> |
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| <col width="19%" /> |
| <col width="43%" /> |
| <col width="38%" /> |
| </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">pred</span></tt></td> |
| <td>Boolean nullary <a class="reference internal" href="./metafunction.html">Metafunction</a></td> |
| <td>A predicate to be asserted.</td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| <div class="section" id="id1291"> |
| <h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> |
| <p>For any boolean nullary <a class="reference internal" href="./metafunction.html">Metafunction</a> <tt class="literal"><span class="pre">pred</span></tt>:</p> |
| <pre class="literal-block"> |
| <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( pred )); |
| </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">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">Generates a compilation error if <tt class="literal"><span class="pre">pred::type::value</span> <span class="pre">!=</span> <span class="pre">true</span></tt>, otherwise |
| has no effect. Note that double parentheses are required even if no commas |
| appear in the condition.</p> |
| <p>When possible within the compiler's diagnostic capabilities, |
| the error message will include the predicate's full type name, and have a |
| general form of:</p> |
| <pre class="last literal-block"> |
| <em>...</em> ************ pred::************ <em>...</em> |
| </pre> |
| </td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| <div class="section" id="id1292"> |
| <h3><a class="subsection-title" href="#example" name="example">Example</a></h3> |
| <pre class="literal-block"> |
| template< typename T, typename U > struct my |
| { |
| // ... |
| <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( is_same< T,U > )); |
| }; |
| |
| my<void*,char*> test; |
| |
| // In instantiation of `my<void, char*>': |
| // instantiated from here |
| // conversion from ` |
| // mpl_::failed************boost::is_same<void, char*>::************' to |
| // non-scalar type `mpl_::assert<false>' requested |
| </pre> |
| </div> |
| <div class="section" id="id1293"> |
| <h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> |
| <p><a class="reference internal" href="./asserts.html">Asserts</a>, <a class="reference internal" href="./assert-not.html">BOOST_MPL_ASSERT_NOT</a>, <a class="reference internal" href="./assert-msg.html">BOOST_MPL_ASSERT_MSG</a>, <a class="reference internal" href="./assert-relation.html">BOOST_MPL_ASSERT_RELATION</a></p> |
| <!-- Macros/Asserts//BOOST_MPL_ASSERT_MSG --> |
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| <td><div class="copyright-footer"><div class="copyright">Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams</div> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
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