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| The <b>BOOST_PP_EMPTY</b> macro is a nullary utility macro that expands to nothing. |
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| <h4>Usage</h4> |
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| <b>BOOST_PP_EMPTY</b>() |
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| <h4>Remarks</h4> |
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| This macro is helps avoid inefficient macro-expansion. |
| It is primarily useful as arguments to <b>BOOST_PP_IF</b> or <b>BOOST_PP_IIF</b>. |
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| <h4>Requirements</h4> |
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| <b>Header:</b> <a href="../headers/facilities/empty.html"><boost/preprocessor/facilities/empty.hpp></a> |
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| <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>> |
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| #define X() result |
| #define MACRO(c) <a href="if.html">BOOST_PP_IF</a>(c, X, <a href="empty.html">BOOST_PP_EMPTY</a>)() |
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| MACRO(0) // expands to nothing |
| MACRO(1) // expands to result |
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| <i>© Copyright <a href="http://www.housemarque.com" target="_top">Housemarque Oy</a> 2002</i> |
| </br><i>© Copyright Paul Mensonides 2002</i> |
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| <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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