boost/libs/preprocessor/doc/ref/tuple_elem.html
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<title>BOOST_PP_TUPLE_ELEM</title>
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<div style="margin-left: 0px;"> The <b>BOOST_PP_TUPLE_ELEM</b>
macro extracts an element from a <i>tuple</i>. </div>
<h4>Usage</h4>
<div class="code"> <b>BOOST_PP_TUPLE_ELEM</b>(<i>i</i>, <i>tuple</i>)
<a
href="file:///E:/Programming/VersionControl/modular-boost/libs/preprocessor/doc/topics/variadic_macros.html#VNotation"
target="_self"><sup>(v)</sup></a><br>
<br>
or<br>
<br>
<b>BOOST_PP_TUPLE_ELEM</b>(<i>size</i>, <i>i</i>, <i>tuple</i>)
<a href="../topics/variadic_macros.html#VNotation" target="_self"><sup>(v)</sup></a><br>
</div>
<h4>Arguments</h4>
<dl>
<dt>size</dt>
<dd> The size of the <i>tuple</i>.&nbsp; The size is ignored.<br>
</dd>
<dt>i</dt>
<dd> The zero-based index into the <i>tuple</i> of the element to
be extracted.&nbsp; Valid values range from <i>0</i> to <i>size</i>
- <i>1</i>. </dd>
<dt>tuple</dt>
<dd> The <i>tuple</i> from which an element is to be extracted. </dd>
</dl>
<h4>Remarks</h4>
<div>You can invoke the variadic macro as BOOST_PP_TUPLE_ELEM(<i>i</i>,<i>tuple</i>),
or BOOST_PP_TUPLE_ELEM(<i>size</i>,<i>i</i>,<i>tuple</i>) for
backward compatibility. </div>
<h4>See Also</h4>
<ul>
<li><a href="limit_tuple.html">BOOST_PP_LIMIT_TUPLE</a></li>
</ul>
<h4>Requirements</h4>
<div> <b>Header:</b> &nbsp;<a href="../headers/tuple/elem.html">&lt;boost/preprocessor/tuple/elem.hpp&gt;</a>
</div>
<h4>Sample Code</h4>
<div>
<pre>#include &lt;<a href="../headers/tuple/elem.html">boost/preprocessor/tuple/elem.hpp</a>&gt;<br><br>#define TUPLE (a, b, c, d)<br><br><a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(0, TUPLE) // expands to a in the variadic version<br><a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(3, TUPLE) // expands to d in the variadic version<br></pre>
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<div style="margin-left: 0px;"> <i><EFBFBD> Copyright <a
href="http://www.housemarque.com" target="_top">Housemarque Oy</a>
2002</i> <br>
<i><EFBFBD> Copyright Paul Mensonides 2002<br>
</i><i><EFBFBD> Copyright Edward Diener 2011,2013,2020</i><br>
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<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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