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| <title>BOOST_PP_LIST_FIRST</title> |
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| The <b>BOOST_PP_LIST_FIRST</b> macro expands to the head of a <i>list</i>. |
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| <h4>Usage</h4> |
| <div class="code"> |
| <b>BOOST_PP_LIST_FIRST</b>(<i>list</i>) |
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| <h4>Arguments</h4> |
| <dl> |
| <dt>list</dt> |
| <dd> |
| A non-nil <i>list</i>. |
| </dd> |
| </dl> |
| <h4>Requirements</h4> |
| <div> |
| <b>Header:</b> <a href="../headers/list/adt.html"><boost/preprocessor/list/adt.hpp></a> |
| </div> |
| <h4>Sample Code</h4> |
| <div><pre> |
| #include <<a href="../headers/list/adt.html">boost/preprocessor/list/adt.hpp</a>> |
| |
| #define OLD \ |
| <a href="list_cons.html">BOOST_PP_LIST_CONS</a>( \ |
| a, \ |
| <a href="list_cons.html">BOOST_PP_LIST_CONS</a>( \ |
| b, \ |
| <a href="list_cons.html">BOOST_PP_LIST_CONS</a>( \ |
| c, \ |
| <a href="list_nil.html">BOOST_PP_LIST_NIL</a> \ |
| ) \ |
| ) \ |
| ) \ |
| /**/ |
| |
| #define NEW (a, (b, (c, <a href="nil.html">BOOST_PP_NIL</a>))) |
| |
| <a href="list_first.html">BOOST_PP_LIST_FIRST</a>(OLD) == <a href="list_first.html">BOOST_PP_LIST_FIRST</a>(NEW) |
| // expands to a == a |
| |
| <a href="list_rest.html">BOOST_PP_LIST_REST</a>(OLD) == <a href="list_rest.html">BOOST_PP_LIST_REST</a>(NEW) |
| // expands to (b, (c, <a href="nil.html">BOOST_PP_NIL</a>)) == (b, (c, <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> |
| </div> |
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