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| <title>BOOST_PP_APPLY</title> |
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| The <b>BOOST_PP_APPLY</b> macro abstracts the difference between an argument and nothing. |
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| <h4>Usage</h4> |
| <div class="code"> |
| <b>BOOST_PP_APPLY</b>(<i>x</i>) |
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| <h4>Arguments</h4> |
| <dl> |
| <dt>x</dt> |
| <dd> |
| The abstracted argument. |
| This argument must be either <b>BOOST_PP_NIL</b> or a <i>tuple</i> with one element--such as <i>(arg)</i> or <i>((a, b))</i>. |
| </dd> |
| </dl> |
| <h4>Remarks</h4> |
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| If <i>x</i> is <b>BOOST_PP_NIL</b>, this macro expands to nothing. |
| If <i>x</i> is a one element <i>tuple</i>, it expands to the contents of that <i>tuple</i>. |
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| <h4>See Also</h4> |
| <ul> |
| <li><a href="nil.html">BOOST_PP_NIL</a></li> |
| </ul> |
| <h4>Requirements</h4> |
| <div> |
| <b>Header:</b> <a href="../headers/facilities/apply.html"><boost/preprocessor/facilities/apply.hpp></a> |
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| <h4>Sample Code</h4> |
| <div><pre> |
| #include <<a href="../headers/facilities/apply.html">boost/preprocessor/facilities/apply.hpp</a>> |
| #include <<a href="../headers/tuple/elem.html">boost/preprocessor/tuple/elem.hpp</a>> |
| |
| #define CV(i) \ |
| <a href="apply.html">BOOST_PP_APPLY</a>( \ |
| <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>( \ |
| 4, i, \ |
| (<a href="nil.html">BOOST_PP_NIL</a>, (const), (volatile), (const volatile)) \ |
| ) \ |
| ) \ |
| /**/ |
| |
| CV(0) // expands to nothing |
| CV(1) // expands to const |
| </pre></div> |
| <hr size="1"> |
| <div style="margin-left: 0px;"> |
| <i>© Copyright <a href="http://www.housemarque.com" target="_top">Housemarque Oy</a> 2002</i> |
| </br><i>© Copyright Paul Mensonides 2002</i> |
| </div> |
| <div style="margin-left: 0px;"> |
| <p><small>Distributed under the Boost Software License, Version 1.0. (See |
| accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or |
| copy at <a href= |
| "http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</small></p> |
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