projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | <html> |
| 2 | <head> | |
| 3 | <title>BOOST_PP_DEDUCE_R</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_DEDUCE_R</b> macro manually deduces the state of the <b>BOOST_PP_FOR</b> construct. | |
| 9 | </div> | |
| 10 | <h4>Usage</h4> | |
| 11 | <div class="code"> | |
| 12 | <b>BOOST_PP_DEDUCE_R</b>() | |
| 13 | </div> | |
| 14 | <h4>Remarks</h4> | |
| 15 | <div> | |
| 16 | This macro is intended to avoid the use of <i>automatic-recursion</i> at deep expansion depths. | |
| 17 | <i>Automatic-recursion</i> at such depths can be inefficient on some preprocessors. | |
| 18 | It is not intended to be used directly with the invocation of macros with a <b>_R</b> suffix such as: | |
| 19 | <div> | |
| 20 | <b>BOOST_PP_LIST_ENUM_R</b>(<b>BOOST_PP_DEDUCE_R</b>(), (a, (b, (c, <b>BOOST_PP_NIL</b>)))) | |
| 21 | </div> | |
| 22 | If it is used in this context, the <b>_R</b> macro will fail. | |
| 23 | The <b>_R</b> macros directly concatenate to the <i>r</i> parameter that is passed to them, | |
| 24 | which would prevent <b>BOOST_PP_DEDUCE_R</b>() from expanding. | |
| 25 | Furthermore, it is pointless to use this macro in a situation such as this | |
| 26 | because it would already be too late to gain any efficiency. | |
| 27 | </div> | |
| 28 | <h4>See Also</h4> | |
| 29 | <ul> | |
| 30 | <li><a href="for.html">BOOST_PP_FOR</a></li> | |
| 31 | </ul> | |
| 32 | <h4>Requirements</h4> | |
| 33 | <div> | |
| 34 | <b>Header:</b> <a href="../headers/repetition/deduce_r.html"><boost/preprocessor/repetition/deduce_r.hpp></a> | |
| 35 | </div> | |
| 36 | <hr size="1"> | |
| 37 | <div style="margin-left: 0px;"> | |
| 38 |