forked from boostorg/preprocessor
55 lines
1.9 KiB
HTML
55 lines
1.9 KiB
HTML
|
<html>
|
||
|
|
<head>
|
||
|
|
<title>BOOST_PP_APPLY</title>
|
||
|
|
<link rel="stylesheet" type="text/css" href="../styles.css">
|
||
|
|
<script language="javascript" type="text/javascript" src="../scripts.js"></script>
|
||
|
|
</head>
|
||
|
|
<body onload="init('sample');">
|
||
|
|
<div style="margin-left: 0px;">
|
||
|
|
The <b>BOOST_PP_APPLY</b> macro abstracts the difference between an argument and nothing.
|
||
|
|
</div>
|
||
|
|
<h4>Usage</h4>
|
||
|
|
<div class="code">
|
||
|
|
<b>BOOST_PP_APPLY</b>(<i>x</i>)
|
||
|
|
</div>
|
||
|
|
<h4>Arguments</h4>
|
||
|
|
<dl>
|
||
|
|
<dt>x</dt>
|
||
|
|
<dd>
|
||
|
|
The abstracted argument.
|
||
|
|
This argument must be either <b>BOOST_PP_NIL</b> or a <i>tuple</i> with one element--such as <i>(arg)</i> or <i>((a, b))</i>.
|
||
|
|
</dd>
|
||
|
|
</dl>
|
||
|
|
<h4>Remarks</h4>
|
||
|
|
<div>
|
||
|
|
If <i>x</i> is <b>BOOST_PP_NIL</b>, this macro expands to nothing.
|
||
|
|
If <i>x</i> is a one element <i>tuple</i>, it expands to the contents of that <i>tuple</i>.
|
||
|
|
</div>
|
||
|
|
<h4>See Also</h4>
|
||
|
|
<ul>
|
||
|
|
<li><a href="nil.html">BOOST_PP_NIL</a></li>
|
||
|
|
</ul>
|
||
|
|
<h4>Requirements</h4>
|
||
|
|
<div>
|
||
|
|
<b>Header:</b> <a href="../headers/facilities/apply.hpp.html"><boost/preprocessor/facilities/apply.hpp></a>
|
||
|
|
</div>
|
||
|
|
<h4><a class="local" onclick="toggle('sample');" onmouseover="change(this);" onmouseout="revert(this);">Sample Code</a></h4>
|
||
|
|
<div id="sample"><pre>
|
||
|
|
#include <boost/preprocessor/facilities/apply.hpp>
|
||
|
|
#include <boost/preprocessor/tuple/elem.hpp>
|
||
|
|
|
||
|
|
#define CV(i) /* .......................................... */ \
|
||
|
|
BOOST_PP_APPLY( \
|
||
|
|
BOOST_PP_TUPLE_ELEM( \
|
||
|
|
4, i, \
|
||
|
|
(BOOST_PP_NIL, (const), (volatile), (const volatile)) \
|
||
|
|
) \
|
||
|
|
) \
|
||
|
|
/**/
|
||
|
|
|
||
|
|
CV(0) // expands to nothing
|
||
|
|
CV(1) // expands to const
|
||
|
|
<pre></div>
|
||
|
|
</body>
|
||
|
|
</html>
|