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

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   3         <title>BOOST_PP_IF</title>
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   8                 The <b>BOOST_PP_IF</b> macro chooses between to values based on a logical condition.
   9         </div>
  10         <h4>Usage</h4>
  11                 <div class="code">
  12                         <b>BOOST_PP_IF</b>(<i>cond</i>, <i>t</i>, <i>f</i>)
  13                 </div>
  14         <h4>Arguments</h4>
  15                 <dl>
  16                         <dt>cond</dt>
  17                         <dd>
  18                                 The condition that determines if the result is <i>expr</i> or nothing.&nbsp;
  19                                 Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>.
  20                         </dd>
  21                         <dt>t</dt>
  22                         <dd>
  23                                 The result of the expansion if <i>cond</i> is non-zero.
  24                         </dd>
  25                         <dt>f</dt>
  26                         <dd>
  27                                 The result of the expansion if <i>cond</i> is <i>0</i>.
  28                         </dd>
  29                 </dl>
  30         <h4>Remarks</h4>
  31                 <div>
  32                         This macro performs a boolean conversion on its first argument.&nbsp;
  33                         If that conversion is unnecessary, use <b>BOOST_PP_IIF</b> instead.
  34                 </div>
  35         <h4>See Also</h4>
  36                 <ul>
  37                         <li><a href="iif.html">BOOST_PP_IIF</a></li>
  38                         <li><a href="limit_mag.html">BOOST_PP_LIMIT_MAG</a></li>
  39                 </ul>
  40         <h4>Requirements</h4>
  41                 <div>
  42                         <b>Header:</b> &nbsp;<a href="../headers/control/if.html">&lt;boost/preprocessor/control/if.hpp&gt;</a>
  43                 </div>
  44         <h4>Sample Code</h4>
  45 <div><pre>
  46 #include &lt;<a href="../headers/control/if.html">boost/preprocessor/control/if.hpp</a>&gt;
  47
  48 <a href="if.html">BOOST_PP_IF</a>(10, a, b) // expands to a
  49 <a href="if.html">BOOST_PP_IF</a>(0, a, b) // expands to b
  50 </pre></div>
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  53                 <i>© Copyright <a href="http://www.housemarque.com" target="_top">Housemarque Oy</a> 2002</i>
  54                 </br><i>© Copyright Paul Mensonides 2002</i>
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  56         <div style="margin-left: 0px;">
  57                 <p><small>Distributed under the Boost Software License, Version 1.0. (See
  58                 accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or
  59                 copy at <a href=
  60                 "http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</small></p>
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