| Brian Silverman | f27e085 | 2018-08-04 23:56:45 -0700 | [diff] [blame^] | 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 | |
| 70 | STRIDE(10, 2) // expands to 6 |
| 71 | STRIDE(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> |