ceph/src/boost/libs/preprocessor/doc/ref/add_d.html

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   3         <title>BOOST_PP_ADD_D</title>
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   8                 The <b>BOOST_PP_ADD_D</b> macro expands to the sum of its second and third arguments.&nbsp;
   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_ADD_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.&nbsp;
  20                         </dd>
  21                         <dt>x</dt>
  22                         <dd>
  23                                 The first addend of the operation.&nbsp;
  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 second addend of the operation.&nbsp;
  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 sum of <i>x</i> and <i>y</i> is greater than <b>BOOST_PP_LIMIT_MAG</b>, the result is saturated to <b>BOOST_PP_LIMIT_MAG</b>.
  35                 </div>
  36                 <div>
  37                         This macro is the most efficient when <i>x</i> is greater than or equal to <i>y</i>.&nbsp;
  38                         However, the efficiency gain is not worth actually comparing the two arguments prior to invocation.&nbsp;
  39                         In other words, <i>x</i> should be the addend that is <i>most likely</i> to be the largest of the two operands.
  40                 </div>
  41         <h4>See Also</h4>
  42                 <ul>
  43                         <li><a href="add.html">BOOST_PP_ADD</a></li>
  44                         <li><a href="limit_mag.html">BOOST_PP_LIMIT_MAG</a></li>
  45                 </ul>
  46         <h4>Requirements</h4>
  47                 <div>
  48                         <b>Header:</b> &nbsp;<a href="../headers/arithmetic/add.html">&lt;boost/preprocessor/arithmetic/add.hpp&gt;</a>
  49                 </div>
  50         <h4>Sample Code</h4>
  51 <div><pre>
  52 #include &lt;<a href="../headers/arithmetic/add.html">boost/preprocessor/arithmetic/add.hpp</a>&gt;
  53 #include &lt;<a href="../headers/arithmetic/dec.html">boost/preprocessor/arithmetic/dec.hpp</a>&gt;
  54 #include &lt;<a href="../headers/control/while.html">boost/preprocessor/control/while.hpp</a>&gt;
  55 #include &lt;<a href="../headers/tuple/elem.html">boost/preprocessor/tuple/elem.hpp</a>&gt;
  56
  57 #define PRED(d, data) <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(2, 0, data)
  58
  59 #define OP(d, data) \
  60    ( \
  61       <a href="dec.html">BOOST_PP_DEC</a>( \
  62          <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(2, 0, data) \
  63       ), \
  64       <a href="add_d.html">BOOST_PP_ADD_D</a>( \
  65          d, \
  66          <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(2, 1, data), \
  67          2 \
  68       ) \
  69    ) \
  70    /**/
  71
  72 // increment 'x' by 2 'n' times
  73 #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)))
  74
  75 STRIDE(10, 2) // expands to 14
  76 STRIDE(51, 6) // expands to 63
  77 </pre></div>
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  80                 <i>© Copyright <a href="http://www.housemarque.com" target="_top">Housemarque Oy</a> 2002</i>
  81                 </br><i>© Copyright Paul Mensonides 2002</i>
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  83         <div style="margin-left: 0px;">
  84                 <p><small>Distributed under the Boost Software License, Version 1.0. (See
  85                 accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or
  86                 copy at <a href=
  87                 "http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</small></p>
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