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| <title>BOOST_PP_IDENTITY</title> |
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| The <b>BOOST_PP_IDENTITY</b> macro expands to its argument when invoked. |
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| <h4>Usage</h4> |
| <div class="code"> |
| <b>BOOST_PP_IDENTITY</b>(<i>item</i>)() |
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| <h4>Arguments</h4> |
| <dl> |
| <dt>item</dt> |
| <dd> |
| The result of the expansion. |
| </dd> |
| </dl> |
| <h4>Remarks</h4> |
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| This macro is designed to be used with <b>BOOST_PP_IF</b> and <b>BOOST_PP_IIF</b> when only one of the clauses needs to be invoked. |
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| <h4>See Also</h4> |
| <ul> |
| <li><a href="if.html">BOOST_PP_IF</a></li> |
| <li><a href="iif.html">BOOST_PP_IIF</a></li> |
| </ul> |
| <h4>Requirements</h4> |
| <div> |
| <b>Header:</b> <a href="../headers/facilities/identity.html"><boost/preprocessor/facilities/identity.hpp></a> |
| </div> |
| <h4>Sample Code</h4> |
| <div><pre> |
| #include <<a href="../headers/control/if.html">boost/preprocessor/control/if.hpp</a>> |
| #include <<a href="../headers/facilities/empty.html">boost/preprocessor/facilities/empty.hpp</a>> |
| #include <<a href="../headers/facilities/identity.html">boost/preprocessor/facilities/identity.hpp</a>> |
| |
| #define MACRO(n) <a href="if.html">BOOST_PP_IF</a>(n, <a href="identity.html">BOOST_PP_IDENTITY</a>(x), <a href="empty.html">BOOST_PP_EMPTY</a>)() |
| |
| MACRO(0) // expands to nothing |
| MACRO(1) // expands to x |
| </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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| </body> |
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