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- <html>
- <head>
- <title>BOOST_PP_SEQ_FILTER</title>
- <link rel="stylesheet" type="text/css" href="../styles.css">
- </head>
- <body>
- <div style="margin-left: 0px;">
- The <b>BOOST_PP_SEQ_FILTER</b> macro filters a <i>seq</i> according to a
- supplied criterion.
- </div>
- <h4>
- Usage
- </h4>
- <div class="code">
- <b>BOOST_PP_SEQ_FILTER</b>(<i>pred</i>, <i>data</i>, <i>seq</i>)
- </div>
- <h4>
- Arguments
- </h4>
- <dl>
- <dt>pred</dt>
- <dd>
- A ternary predicate of the form <i>pred</i>(<i>s</i>, <i>data</i>, <i>elem</i>).
- This predicate is expanded by <b>BOOST_PP_SEQ_FILTER</b> for each element in <i>seq</i>
- with the next available <b>BOOST_PP_SEQ_FOLD_LEFT</b> fold step, the auxiliary <i>data</i>,
- and the current element in <i>seq</i>. This macro must return a integral
- value in the range of <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>. If this
- predicate expands to non-zero for a certain element, that element is included
- in the resulting <i>seq</i>.
- </dd>
- <dt>data</dt>
- <dd>
- Auxiliary data passed to <i>pred</i>.
- </dd>
- <dt>seq</dt>
- <dd>
- The <i>seq</i> to be filtered.
- </dd>
- </dl>
- <h4>
- Remarks
- </h4>
- <div>
- This macro expands <i>pred</i> for each element in <i>seq</i>. It builds
- a new <i>seq</i> out of each element for which <i>pred</i> returns non-zero.
- </div>
- <div>
- For maximum efficiency, use <b>BOOST_PP_SEQ_FILTER_S</b>.
- </div>
- <h4>
- See Also
- </h4>
- <ul>
- <li>
- <a href="limit_mag.html">BOOST_PP_LIMIT_MAG</a></li>
- <li>
- <a href="seq_filter_s.html">BOOST_PP_SEQ_FILTER_S</a></li>
- </ul>
- <h4>
- Requirements
- </h4>
- <div>
- <b>Header:</b> <a href="../headers/seq/filter.html"><boost/preprocessor/seq/filter.hpp></a>
- </div>
- <h4>
- Sample Code
- </h4>
- <div>
- <pre>
- #include <<a href="../headers/comparison/less_equal.html">boost/preprocessor/comparison/less_equal.hpp</a>>
- #include <<a href="../headers/seq/filter.html">boost/preprocessor/seq/filter.hpp</a>>
- #define SEQ (1)(3)(2)(5)
- #define PRED(s, data, elem) <a href="less_equal.html">BOOST_PP_LESS_EQUAL</a>(elem, data)
- <a href="seq_filter.html">BOOST_PP_SEQ_FILTER</a>(PRED, 3, SEQ)
- // expands to (1)(3)(2)
- </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>
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