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<title>BOOST_PP_EMPTY</title>
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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>
<div class="code">
<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>>
#define X() result
#define MACRO(c) <a href="if.html">BOOST_PP_IF</a>(c, X, <a href="empty.html">BOOST_PP_EMPTY</a>)()
MACRO(0) // expands to nothing
MACRO(1) // expands to result
</pre></div>
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<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>
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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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