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1<html>
2<head>
3	<title>BOOST_PP_COMMA_IF</title>
4	<link rel="stylesheet" type="text/css" href="../styles.css">
5</head>
6<body>
7	<div style="margin-left:  0px;">
8		The <b>BOOST_PP_COMMA_IF</b> macro conditionally expands to a comma.
9	</div>
10	<h4>Usage</h4>
11		<div class="code">
12			<b>BOOST_PP_COMMA_IF</b>(<i>cond</i>)
13		</div>
14	<h4>Arguments</h4>
15		<dl>
16			<dt>cond</dt>
17			<dd>
18				The condition that determines if a the macro expands to a comma or nothing.&nbsp;
19				Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>.
20			</dd>
21		</dl>
22	<h4>Remarks</h4>
23		<div>
24			If <i>cond</i> expands to <i>0</i>, this macro expands to nothing.&nbsp;
25			Otherwise, it expands to a comma.
26		</div>
27		<div>
28			The preprocessor interprets commas as argument separators in macro invocations.&nbsp;
29			Because of this, commas require special handling.
30		</div>
31	<h4>See Also</h4>
32		<ul>
33			<li><a href="limit_mag.html">BOOST_PP_LIMIT_MAG</a></li>
34		</ul>
35	<h4>Requirements</h4>
36		<div>
37			<b>Header:</b> &nbsp;<a href="../headers/punctuation/comma_if.html">&lt;boost/preprocessor/punctuation/comma_if.hpp&gt;</a>
38		</div>
39	<h4>Sample Code</h4>
40<div><pre>
41#include &lt;<a href="../headers/punctuation/comma_if.html">boost/preprocessor/punctuation/comma_if.hpp</a>&gt;
42#include &lt;<a href="../headers/repetition/repeat.html">boost/preprocessor/repetition/repeat.hpp</a>&gt;
43
44#define MACRO(z, n, text) <a href="comma_if.html">BOOST_PP_COMMA_IF</a>(n) text
45
46<a href="repeat.html">BOOST_PP_REPEAT</a>(3, MACRO, class) // expands to class, class, class
47</pre></div>
48	<hr size="1">
49	<div style="margin-left: 0px;">
50		<i>� Copyright <a href="http://www.housemarque.com" target="_top">Housemarque Oy</a> 2002</i>
51		</br><i>� Copyright Paul Mensonides 2002</i>
52	</div>
53	<div style="margin-left: 0px;">
54		<p><small>Distributed under the Boost Software License, Version 1.0. (See
55		accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or
56		copy at <a href=
57		"http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</small></p>
58	</div>
59</body>
60</html>
61