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lib cleanup

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[SVN r15693]
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Paul Mensonides
2002-10-03 22:13:37 +00:00
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commit 4bb690a819
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<html>
<head>
<title>BOOST_PP_IDENTITY</title>
<link rel="stylesheet" type="text/css" href="../styles.css">
</head>
<body>
<div style="margin-left: 0px;">
The <b>BOOST_PP_IDENTITY</b> macro expands to its argument when invoked.
</div>
<h4>Usage</h4>
<div class="code">
<b>BOOST_PP_IDENTITY</b>(<i>item</i>)()
</div>
<h4>Arguments</h4>
<dl>
<dt>item</dt>
<dd>
The result of the expansion.
</dd>
</dl>
<h4>Remarks</h4>
<div>
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.
</div>
<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> &nbsp;<a href="../headers/facilities/identity.hpp.html">&lt;boost/preprocessor/facilities/identity.hpp&gt;</a>
</div>
<h4>Sample Code</h4>
<div><pre>
#include &lt;<a href="../headers/control/if.hpp.html">boost/preprocessor/control/if.hpp</a>&gt;
#include &lt;<a href="../headers/facilities/empty.hpp.html">boost/preprocessor/facilities/empty.hpp</a>&gt;
#include &lt;<a href="../headers/facilities/identity.hpp.html">boost/preprocessor/facilities/identity.hpp</a>&gt;
#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>
</body>
</html>