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| <div class="section" id="boost-mpl-assert-relation"> |
| <h1><a class="toc-backref" href="./asserts.html#id1591">BOOST_MPL_ASSERT_RELATION</a></h1> |
| <div class="section" id="id1308"> |
| <h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3> |
| <pre class="literal-block"> |
| #define <a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( x, relation, y ) \ |
| <em>unspecified token sequence</em> \ |
| /**/ |
| </pre> |
| </div> |
| <div class="section" id="id1309"> |
| <h3><a class="subsection-title" href="#description" name="description">Description</a></h3> |
| <p>A specialized assertion macro for checking numerical conditions. Generates |
| a compilation error when the condition <tt class="literal"><span class="pre">(</span> <span class="pre">x</span> <span class="pre">relation</span> <span class="pre">y</span> <span class="pre">)</span></tt> |
| doesn't hold.</p> |
| </div> |
| <div class="section" id="id1310"> |
| <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="id1311"> |
| <h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3> |
| <table border="1" class="docutils table"> |
| <colgroup> |
| <col width="15%" /> |
| <col width="36%" /> |
| <col width="48%" /> |
| </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">x</span></tt></td> |
| <td>An integral constant</td> |
| <td>Left operand of the checked relation.</td> |
| </tr> |
| <tr><td><tt class="literal"><span class="pre">y</span></tt></td> |
| <td>An integral constant</td> |
| <td>Right operand of the checked relation.</td> |
| </tr> |
| <tr><td><tt class="literal"><span class="pre">relation</span></tt></td> |
| <td>A C++ operator token</td> |
| <td>An operator token for the relation being |
| checked.</td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| <div class="section" id="id1312"> |
| <h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> |
| <p>For any integral constants <tt class="literal"><span class="pre">x</span></tt>, <tt class="literal"><span class="pre">y</span></tt> and a legal C++ operator token <tt class="literal"><span class="pre">op</span></tt>:</p> |
| <pre class="literal-block"> |
| <a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( x, op, y ); |
| </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">(</span> <span class="pre">x</span> <span class="pre">op</span> <span class="pre">y</span> <span class="pre">)</span> <span class="pre">!=</span> <span class="pre">true</span></tt>, otherwise |
| has no effect.</p> |
| <p>When possible within the compiler's diagnostic capabilities, |
| the error message will include a name of the relation being checked, |
| the actual values of both operands, and have a general form of:</p> |
| <pre class="last literal-block"> |
| <em>...</em> ************<em>...</em>assert_relation<op, x, y>::************) <em>...</em> |
| </pre> |
| </td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| <div class="section" id="id1313"> |
| <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-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( sizeof(T), <, sizeof(U) ); |
| }; |
| |
| my<char[50],char[10]> test; |
| |
| // In instantiation of `my<char[50], char[10]>': |
| // instantiated from here |
| // conversion from ` |
| // mpl_::failed************mpl_::assert_relation<<a href="./less.html" class="identifier">less</a>, 50, 10>::************' |
| // to non-scalar type `mpl_::assert<false>' requested |
| </pre> |
| </div> |
| <div class="section" id="id1314"> |
| <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.html">BOOST_MPL_ASSERT</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></p> |
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