48 lines
1.6 KiB
HTML
48 lines
1.6 KiB
HTML
<html>
|
|
<head>
|
|
<title>BOOST_PP_EMPTY</title>
|
|
<link rel="stylesheet" type="text/css" href="../styles.css">
|
|
|
|
</head>
|
|
<body>
|
|
<div style="margin-left: 0px;">
|
|
The <b>BOOST_PP_EMPTY</b> macro is a nullary utility macro that expands to nothing.
|
|
</div>
|
|
<h4>Usage</h4>
|
|
<div class="code">
|
|
<b>BOOST_PP_EMPTY</b>()
|
|
</div>
|
|
<h4>Remarks</h4>
|
|
<div>
|
|
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>.
|
|
</div>
|
|
<h4>Requirements</h4>
|
|
<div>
|
|
<b>Header:</b> <a href="../headers/facilities/empty.html"><boost/preprocessor/facilities/empty.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>>
|
|
|
|
#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>
|
|
<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>
|
|
</div>
|
|
</body>
|
|
</html>
|