| Brian Silverman | f27e085 | 2018-08-04 23:56:45 -0700 | [diff] [blame^] | 1 | <html> |
| 2 | <head> |
| 3 | <meta content="text/html; charset=windows-1252" http-equiv="content-type"> |
| 4 | <title>BOOST_PP_OVERLOAD</title> |
| 5 | <link rel="stylesheet" type="text/css" href="../styles.css"> |
| 6 | </head> |
| 7 | <body> |
| 8 | <div style="margin-left: 0px;"> The <b>BOOST_PP_OVERLOAD</b> variadic |
| 9 | macro expands to the name of a non-variadic macro having a given number of |
| 10 | parameters.<br> |
| 11 | </div> |
| 12 | <h4>Usage</h4> |
| 13 | <div class="code"> <b>BOOST_PP_OVERLOAD</b>(<i>prefix</i>,...) <a href="../topics/variadic_macros.html#VNotation" |
| 14 | target="_self"><sup>(v)</sup></a><br> |
| 15 | </div> |
| 16 | <h4>Arguments</h4> |
| 17 | <dl> |
| 18 | <dt>prefix<br> |
| 19 | </dt> |
| 20 | <dd> The prefix of the non-variadic macro name. </dd> |
| 21 | <dt>...<br> |
| 22 | </dt> |
| 23 | <dd><i> Variadic data</i>. The number of variadic data |
| 24 | elements, as determined by BOOST_PP_VARIADIC_SIZE, is appended to the |
| 25 | prefix to form the output non-variadic macro name.<br> |
| 26 | </dd> |
| 27 | </dl> |
| 28 | <h4>Remarks</h4> |
| 29 | <div> This macro creates a macro name which depends on the number of |
| 30 | elements of variadic data. It should be used in the form of <br> |
| 31 | BOOST_PP_OVERLOAD(MACRO_NAME_,__VA_ARGS__)(__VA_ARGS__) in order to |
| 32 | call a non-variadic macro taking a given number of variadic data |
| 33 | elements as non-variadic arguments. In this way one can invoke a |
| 34 | variadic macro with a variable number of parameters which calls one of |
| 35 | a series of non-variadic macros doing very similar things. |
| 36 | </div> |
| 37 | <b>Requirements</b> |
| 38 | <div> <b>Header:</b> <a href="../headers/facilities/overload.html"><boost/preprocessor/facilities/overload.hpp></a> |
| 39 | </div> |
| 40 | <h4>Sample Code</h4> |
| 41 | <div> |
| 42 | <pre>#include <<a href="../headers/facilities/overload.html">boost/preprocessor/facilities/overload.hpp</a>><br>#include <<a |
| 43 | href="../headers/cat.html">boost/preprocessor/cat.hpp</a>><br>#include <<a href="../headers/facilities/empty.html">boost/preprocessor/facilities/empty.hpp</a>><br>#include <<a |
| 44 | href="../headers/arithmetic/add.html">boost/preprocessor/arithmetic/add.hpp</a>><br><br>#define MACRO_1(number) MACRO_2(number,10)<br>#define MACRO_2(number1,number2) <a |
| 45 | href="add.html">BOOST_PP_ADD</a>(number1,number2)<br><br>#if !BOOST_PP_VARIADICS_MSVC<br><br>#define MACRO_ADD_NUMBERS(...) <a |
| 46 | href="overload.html">BOOST_PP_OVERLOAD</a>(MACRO_,__VA_ARGS__)(__VA_ARGS__)<br><br>#else<br><br>// or for Visual C++<br><br>#define MACRO_ADD_NUMBERS(...) \<br> <a |
| 47 | href="cat.html">BOOST_PP_CAT</a>(<a href="overload.html">BOOST_PP_OVERLOAD</a>(MACRO_,__VA_ARGS__)(__VA_ARGS__),<a |
| 48 | href="empty.html">BOOST_PP_EMPTY</a>())<br><br>#endif<br><br>MACRO_ADD_NUMBERS(5) // output is 15<br>MACRO_ADD_NUMBERS(3,6) // output is 9</pre> |
| 49 | </div> |
| 50 | <hr size="1"> |
| 51 | <div style="margin-left: 0px;"> <i></i><i>© Copyright Edward Diener 2011,2013,2016</i> </div> |
| 52 | <div style="margin-left: 0px;"> |
| 53 | <p><small>Distributed under the Boost Software License, Version 1.0. |
| 54 | (See accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> |
| 55 | or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</small></p> |
| 56 | </div> |
| 57 | |
| 58 | </body></html> |