1<html> 2 <head> 3 <title>BOOST_PP_TUPLE_ELEM</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_TUPLE_ELEM</b> macro extracts an element from a <i>tuple</i>. 9 </div> 10 <h4>Usage</h4> 11 <div class="code"> 12 <b>BOOST_PP_TUPLE_ELEM</b>(<i>size</i>, <i>i</i>, <i>tuple</i>)<sup></sup><br> 13<br> 14or<br> 15<br> 16<b>BOOST_PP_TUPLE_ELEM</b>(<i>...</i>) <a href="../topics/variadic_macros.html#VNotation" target="_self"><sup>(v)</sup></a><b></b><br> 17</div> 18 <h4>Arguments</h4> 19 <dl> 20 <dt>size</dt> 21 <dd> 22 The size of the <i>tuple</i>. 23 Valid <i>tuple</i> sizes range from <i>1</i> to <b>BOOST_PP_LIMIT_TUPLE</b>. 24 </dd> 25 <dt>i</dt> 26 <dd> 27 The zero-based index into the <i>tuple</i> of the element to be extracted. 28 Valid values range from <i>0</i> to <i>size</i> - <i>1</i>. 29 </dd> 30 <dt>tuple</dt> 31 <dd> 32 The <i>tuple</i> from which an element is to be extracted. 33 </dd> 34 </dl> 35 <h4>Remarks</h4> 36 <div> 37 The <i>size</i> argument must be the actual size of the <i>tuple</i>, 38 and <i>i</i> must be less than the size of the <i>tuple</i>. <br> 39 <br>You can 40 invoke the variadic version as BOOST_PP_TUPLE_ELEM(<i>i</i>,<i>tuple</i>) or 41 BOOST_PP_TUPLE_ELEM(<i>size</i>,<i>i</i>,<i>tuple</i>). 42 </div> 43 <h4>See Also</h4> 44 <ul> 45 <li><a href="limit_tuple.html">BOOST_PP_LIMIT_TUPLE</a></li> 46 </ul> 47 <h4>Requirements</h4> 48 <div> 49 <b>Header:</b> <a href="../headers/tuple/elem.html"><boost/preprocessor/tuple/elem.hpp></a> 50 </div> 51 <h4>Sample Code</h4> 52<div><pre>#include <<a href="../headers/tuple/elem.html">boost/preprocessor/tuple/elem.hpp</a>><br><br>#define TUPLE (a, b, c, d)<br><br><a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(4, 0, TUPLE) // expands to a<br><a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(4, 3, TUPLE) // expands to d<br><br>// or for the variadic version <a href="../topics/variadic_macros.html#VNotation" target="_self"><sup>(v)</sup></a><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></div> 53 <hr size="1"> 54 <div style="margin-left: 0px;"> 55 <i>� Copyright <a href="http://www.housemarque.com" target="_top">Housemarque Oy</a> 2002</i> 56 <br><i>� Copyright Paul Mensonides 2002<br> 57 </i><i>� Copyright Edward Diener 2011,2013</i><br> 58 </div> 59 <div style="margin-left: 0px;"> 60 <p><small>Distributed under the Boost Software License, Version 1.0. (See 61 accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or 62 copy at <a href="http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</small></p> 63 </div> 64 </body> 65</html>