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| <title>BOOST_PP_LIST_FIRST_N</title> |
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| The <b>BOOST_PP_LIST_FIRST_N</b> macro expands to a <i>list</i> of the first <i>count</i> elements of a <i>list</i>. |
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| <h4>Usage</h4> |
| <div class="code"> |
| <b>BOOST_PP_LIST_FIRST_N</b>(<i>count</i>, <i>list</i>) |
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| <h4>Arguments</h4> |
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| <dt>count</dt> |
| <dd> |
| The number of elements to extract. |
| </dd> |
| <dt>list</dt> |
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| The <i>list</i> from which the elements are extracted. |
| </dd> |
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| <h4>Remarks</h4> |
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| This macro extracts <i>count</i> elements from the beginning of <i>list</i> and returns them as a <i>list</i> |
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| Previously, this macro could not be used inside <b>BOOST_PP_WHILE</b>. |
| There is no longer any such restriction. |
| It is more efficient, however, to use <b>BOOST_PP_LIST_FIRST_N_D</b> in such a situation. |
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| <h4>See Also</h4> |
| <ul> |
| <li><a href="list_first_n_d.html">BOOST_PP_LIST_FIRST_N_D</a></li> |
| </ul> |
| <h4>Requirements</h4> |
| <div> |
| <b>Header:</b> <a href="../headers/list/first_n.html"><boost/preprocessor/list/first_n.hpp></a> |
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| <h4>Sample Code</h4> |
| <div><pre> |
| #include <<a href="../headers/list/first_n.html">boost/preprocessor/list/first_n.hpp</a>> |
| |
| #define LIST (a, (b, (c, <a href="nil.html">BOOST_PP_NIL</a>))) |
| |
| <a href="list_first_n.html">BOOST_PP_LIST_FIRST_N</a>(2, LIST) // expands to (a, (b, <a href="nil.html">BOOST_PP_NIL</a>)) |
| </pre></div> |
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| <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> |
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