]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
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 |