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

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   3         <title>BOOST_PP_ENUM_z</title>
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   8                 The <b>BOOST_PP_ENUM_<i>z</i></b> macro represents a reentry into the <b>BOOST_PP_ENUM</b> repetition construct.
   9         </div>
  10         <h4>Usage</h4>
  11                 <div class="code">
  12                         <b>BOOST_PP_ENUM_</b> ## <i>z</i>(<i>count</i>, <i>macro</i>, <i>data</i>)
  13                 </div>
  14         <h4>Arguments</h4>
  15                 <dl>
  16                         <dt>z</dt>
  17                         <dd>
  18                                 The next available <b>BOOST_PP_REPEAT</b> dimension.
  19                         </dd>
  20                         <dt>count</dt>
  21                         <dd>
  22                                 The number of repetitious calls to <i>macro</i>.&nbsp;
  23                                 Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_REPEAT</b>.
  24                         </dd>
  25                         <dt>macro</dt>
  26                         <dd>
  27                                 A ternary operation of the form <i>macro</i>(<i>z</i>, <i>n</i>, <i>data</i>).&nbsp;
  28                                 This macro is expanded by <b>BOOST_PP_ENUM</b> with the next available repetition depth,
  29                                 the current repetition number, and the auxiliary <i>data</i> argument.&nbsp;
  30                         </dd>
  31                         <dt>data</dt>
  32                         <dd>
  33                                 Auxiliary data passed to <i>macro</i>.
  34                         </dd>
  35                 </dl>
  36         <h4>Remarks</h4>
  37                 <div>
  38                         This macro expands to the sequence:
  39                         <div>
  40                                 <i>macro</i>(<i>z</i>, <i>0</i>, <i>data</i>), <i>macro</i>(<i>z</i>, <i>1</i>, <i>data</i>), ... <i>macro</i>(<i>z</i>, <i>count</i> - <i>1</i>, <i>data</i>)
  41                         </div>
  42                 </div>
  43                 <div>
  44                         At certain times, it may be necessary to perform the concatenation with <b>BOOST_PP_CAT</b> rather than the preprocessor token-pasting operator.&nbsp;
  45                         This happens when the <i>z</i> value is a macro invocation itself.&nbsp;
  46                         It needs a delay to allow it to expand.&nbsp;
  47                         The syntax in such a scenario becomes:
  48                         <div>
  49                                 <b>BOOST_PP_CAT</b>(<b>BOOST_PP_ENUM_</b>, <i>z</i>)(<i>count</i>, <i>macro</i>, <i>data</i>)
  50                         </div>
  51                 </div>
  52         <h4>See Also</h4>
  53                 <ul>
  54                         <li><a href="cat.html">BOOST_PP_CAT</a></li>
  55                         <li><a href="enum.html">BOOST_PP_ENUM</a></li>
  56                         <li><a href="limit_repeat.html">BOOST_PP_LIMIT_REPEAT</a></li>
  57                 </ul>
  58         <h4>Requirements</h4>
  59                 <div>
  60                         <b>Header:</b> &nbsp;<a href="../headers/repetition/enum.html">&lt;boost/preprocessor/repetition/enum.hpp&gt;</a>
  61                 </div>
  62         <h4>Sample Code</h4>
  63 <div><pre>
  64 #include &lt;<a href="../headers/arithmetic/inc.html">boost/preprocessor/arithmetic/inc.hpp</a>&gt;
  65 #include &lt;<a href="../headers/repetition/enum.html">boost/preprocessor/repetition/enum.hpp</a>&gt;
  66
  67 #define TEXT(z, n, text) text
  68
  69 #define TTP(z, n, _) \
  70    template&lt; \
  71       <a href="enum_z.html">BOOST_PP_ENUM_</a> ## z(<a href="inc.html">BOOST_PP_INC</a>(n), TEXT, class) \
  72    &gt; \
  73    class T ## n \
  74    /**/
  75
  76 <a href="enum.html">BOOST_PP_ENUM</a>(3, TTP, nil)
  77    /*
  78       expands to...
  79       template&lt;class&gt; class T0,
  80       template&lt;class, class&gt; class T1,
  81       template&lt;class, class, class&gt; class T2
  82    */
  83 </pre></div>
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  86                 <i>© Copyright <a href="http://www.housemarque.com" target="_top">Housemarque Oy</a> 2002</i>
  87                 </br><i>© Copyright Paul Mensonides 2002</i>
  88         </div>
  89         <div style="margin-left: 0px;">
  90                 <p><small>Distributed under the Boost Software License, Version 1.0. (See
  91                 accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or
  92                 copy at <a href=
  93                 "http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</small></p>
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