1<html> 2<head> 3 <title>BOOST_PP_SUB_D</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_SUB_D</b> macro expands to the difference between its second and third arguments. 9 It reenters <b>BOOST_PP_WHILE</b> with maximum efficiency. 10 </div> 11 <h4>Usage</h4> 12 <div class="code"> 13 <b>BOOST_PP_SUB_D</b>(<i>d</i>, <i>x</i>, <i>y</i>) 14 </div> 15 <h4>Arguments</h4> 16 <dl> 17 <dt>d</dt> 18 <dd> 19 The next available <b>BOOST_PP_WHILE</b> iteration. 20 </dd> 21 <dt>x</dt> 22 <dd> 23 The minuend of the operation. 24 Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>. 25 </dd> 26 <dt>y</dt> 27 <dd> 28 The subtrahend of the operation. 29 Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>. 30 </dd> 31 </dl> 32 <h4>Remarks</h4> 33 <div> 34 If the difference between <i>x</i> and <i>y</i> is less than <i>0</i>, the result is saturated to <i>0</i>. 35 </div> 36 <h4>See Also</h4> 37 <ul> 38 <li><a href="limit_mag.html">BOOST_PP_LIMIT_MAG</a></li> 39 <li><a href="sub.html">BOOST_PP_SUB</a></li> 40 </ul> 41 <h4>Requirements</h4> 42 <div> 43 <b>Header:</b> <a href="../headers/arithmetic/sub.html"><boost/preprocessor/arithmetic/sub.hpp></a> 44 </div> 45 <h4>Sample Code</h4> 46<div><pre> 47#include <<a href="../headers/arithmetic/dec.html">boost/preprocessor/arithmetic/dec.hpp</a>> 48#include <<a href="../headers/arithmetic/sub.html">boost/preprocessor/arithmetic/sub.hpp</a>> 49#include <<a href="../headers/control/while.html">boost/preprocessor/control/while.hpp</a>> 50#include <<a href="../headers/tuple/elem.html">boost/preprocessor/tuple/elem.hpp</a>> 51 52#define PRED(d, data) <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(2, 0, data) 53 54#define OP(d, data) \ 55 ( \ 56 <a href="dec.html">BOOST_PP_DEC</a>( \ 57 <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(2, 0, data) \ 58 ), \ 59 <a href="sub_d.html">BOOST_PP_SUB_D</a>( \ 60 d, \ 61 <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(2, 1, data), \ 62 2 \ 63 ) \ 64 ) \ 65 /**/ 66 67// decrement 'x' by 2 'n' times 68#define STRIDE(x, n) <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(2, 1, <a href="while.html">BOOST_PP_WHILE</a>(PRED, OP, (n, x))) 69 70STRIDE(10, 2) // expands to 6 71STRIDE(14, 6) // expands to 2 72</pre></div> 73 <hr size="1"> 74 <div style="margin-left: 0px;"> 75 <i>� Copyright <a href="http://www.housemarque.com" target="_top">Housemarque Oy</a> 2002</i> 76 </br><i>� Copyright Paul Mensonides 2002</i> 77 </div> 78 <div style="margin-left: 0px;"> 79 <p><small>Distributed under the Boost Software License, Version 1.0. (See 80 accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or 81 copy at <a href= 82 "http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</small></p> 83 </div> 84</body> 85</html> 86