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| <title>BOOST_PP_DEDUCE_D</title> |
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| The <b>BOOST_PP_DEDUCE_D</b> macro manually deduces the state of the <b>BOOST_PP_WHILE</b> construct. |
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| <h4>Usage</h4> |
| <div class="code"> |
| <b>BOOST_PP_DEDUCE_D</b>() |
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| <h4>Remarks</h4> |
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| This macro is intended to avoid the use of <i>automatic-recursion</i> at deep expansion depths. |
| <i>Automatic-recursion</i> at such depths can be inefficient on some preprocessors. |
| It is not intended to be used directly with the invocation of macros with a <b>_D</b> suffix such as: |
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| <b>BOOST_PP_ADD_D</b>(<b>BOOST_PP_DEDUCE_D</b>(), <i>x</i>, <i>y</i>) |
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| If it is used in this context, the <b>_D</b> macro will fail. |
| The <b>_D</b> macros directly concatenate to the <i>d</i> parameter that is passed to them, |
| which would prevent <b>BOOST_PP_DEDUCE_D</b>() from expanding. |
| Furthermore, it is pointless to use this macro in a situation such as this |
| because it would already be too late to gain any efficiency. |
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| <h4>See Also</h4> |
| <ul> |
| <li><a href="while.html">BOOST_PP_WHILE</a></li> |
| </ul> |
| <h4>Requirements</h4> |
| <div> |
| <b>Header:</b> <a href="../headers/control/deduce_d.html"><boost/preprocessor/control/deduce_d.hpp></a> |
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| <h4>Sample Code</h4> |
| <div><pre> |
| #include <<a href="../headers/arithmetic/add.html">boost/preprocessor/arithmetic/add.hpp</a>> |
| #include <<a href="../headers/arithmetic/inc.html">boost/preprocessor/arithmetic/inc.hpp</a>> |
| #include <<a href="../headers/arithmetic/sub.html">boost/preprocessor/arithmetic/sub.hpp</a>> |
| #include <<a href="../headers/control/deduce_d.html">boost/preprocessor/control/deduce_d.hpp</a>> |
| #include <<a href="../headers/punctuation/comma_if.html">boost/preprocessor/punctuation/comma_if.hpp</a>> |
| #include <<a href="../headers/repetition/repeat.html">boost/preprocessor/repetition/repeat.hpp</a>> |
| #include <<a href="../headers/tuple/elem.html">boost/preprocessor/tuple/elem.hpp</a>> |
| |
| #define RANGE(first, last) \ |
| <a href="repeat.html">BOOST_PP_REPEAT</a>( \ |
| <a href="inc.html">BOOST_PP_INC</a>( \ |
| <a href="sub.html">BOOST_PP_SUB</a>(last, first) \ |
| ), \ |
| RANGE_M, \ |
| (first, <a href="deduce_d.html">BOOST_PP_DEDUCE_D</a>()) \ |
| ) \ |
| /**/ |
| |
| #define RANGE_M(z, n, data) \ |
| RANGE_M_2( \ |
| n, \ |
| <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(2, 0, data), \ |
| <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(2, 1, data) \ |
| ) \ |
| /**/ |
| |
| #define RANGE_M_2(n, first, d) \ |
| <a href="comma_if.html">BOOST_PP_COMMA_IF</a>(n) <a href="add_d.html">BOOST_PP_ADD_D</a>(d, n, first) \ |
| /**/ |
| |
| RANGE(5, 10) // expands to 5, 6, 7, 8, 9, 10 |
| </pre></div> |
| <hr size="1"> |
| <div style="margin-left: 0px;"> |
| <i>© Copyright <a href="http://www.housemarque.com" target="_top">Housemarque Oy</a> 2002</i> |
| </br><i>© Copyright Paul Mensonides 2002</i> |
| </div> |
| <div style="margin-left: 0px;"> |
| <p><small>Distributed under the Boost Software License, Version 1.0. (See |
| accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or |
| copy at <a href= |
| "http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</small></p> |
| </div> |
| </body> |
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