mirror of
https://github.com/boostorg/preprocessor.git
synced 2025-06-30 06:20:57 +02:00
Compare commits
4 Commits
boost-1.60
...
boost-1.63
| Author | SHA1 | Date | |
|---|---|---|---|
| c2beb74b90 | |||
| 3292532517 | |||
| b1be22cf77 | |||
| f59d83b8bf |
@ -1,46 +1,58 @@
|
||||
<html>
|
||||
<head>
|
||||
<meta content="text/html; charset=windows-1252" http-equiv="content-type">
|
||||
<title>BOOST_PP_OVERLOAD</title>
|
||||
<link rel="stylesheet" type="text/css" href="../styles.css">
|
||||
<link rel="stylesheet" type="text/css" href="../styles.css">
|
||||
</head>
|
||||
<body>
|
||||
<div style="margin-left: 0px;"> The <b>BOOST_PP_OVERLOAD</b> variadic macro expands to the name of a non-variadic macro having a given number of parameters.<br>
|
||||
</div>
|
||||
<h4>Usage</h4>
|
||||
<div class="code"> <b>BOOST_PP_OVERLOAD</b>(<i>prefix</i>,...) <a href="../topics/variadic_macros.html#VNotation" target="_self"><sup>(v)</sup></a><br>
|
||||
</div>
|
||||
<h4>Arguments</h4>
|
||||
<dl>
|
||||
<dt>prefix<br>
|
||||
</dt><dd>
|
||||
The prefix of the non-variadic macro name.
|
||||
</dd><dt>...<br>
|
||||
</dt><dd><i>
|
||||
Variadic data</i>. The number of variadic data
|
||||
elements, as determined by BOOST_PP_VARIADIC_SIZE, is appended to the
|
||||
prefix to form the output non-variadic macro name.<br>
|
||||
</dd>
|
||||
</dl>
|
||||
<h4>Remarks</h4>
|
||||
<div> This macro creates a macro name which depends on the number of elements of variadic data. It should be used in the form of <br>
|
||||
BOOST_PP_OVERLOAD(MACRO_NAME_,__VA_ARGS__)(__VA_ARGS__) in order to
|
||||
call a non-variadic macro taking a given number of variadic data
|
||||
elements as non-variadic arguments. In this way one can invoke a
|
||||
variadic macro with a variable number of parameters which calls one of
|
||||
a series of non-variadic macros doing very similar things.
|
||||
</div><b>Requirements</b>
|
||||
<div> <b>Header:</b> <a href="../headers/facilities/overload.html"><boost/preprocessor/facilities/overload.hpp></a>
|
||||
<div style="margin-left: 0px;"> The <b>BOOST_PP_OVERLOAD</b> variadic
|
||||
macro expands to the name of a non-variadic macro having a given number of
|
||||
parameters.<br>
|
||||
</div>
|
||||
<h4>Usage</h4>
|
||||
<div class="code"> <b>BOOST_PP_OVERLOAD</b>(<i>prefix</i>,...) <a href="../topics/variadic_macros.html#VNotation"
|
||||
target="_self"><sup>(v)</sup></a><br>
|
||||
</div>
|
||||
<h4>Arguments</h4>
|
||||
<dl>
|
||||
<dt>prefix<br>
|
||||
</dt>
|
||||
<dd> The prefix of the non-variadic macro name. </dd>
|
||||
<dt>...<br>
|
||||
</dt>
|
||||
<dd><i> Variadic data</i>. The number of variadic data
|
||||
elements, as determined by BOOST_PP_VARIADIC_SIZE, is appended to the
|
||||
prefix to form the output non-variadic macro name.<br>
|
||||
</dd>
|
||||
</dl>
|
||||
<h4>Remarks</h4>
|
||||
<div> This macro creates a macro name which depends on the number of
|
||||
elements of variadic data. It should be used in the form of <br>
|
||||
BOOST_PP_OVERLOAD(MACRO_NAME_,__VA_ARGS__)(__VA_ARGS__) in order to
|
||||
call a non-variadic macro taking a given number of variadic data
|
||||
elements as non-variadic arguments. In this way one can invoke a
|
||||
variadic macro with a variable number of parameters which calls one of
|
||||
a series of non-variadic macros doing very similar things.
|
||||
</div>
|
||||
<b>Requirements</b>
|
||||
<div> <b>Header:</b> <a href="../headers/facilities/overload.html"><boost/preprocessor/facilities/overload.hpp></a>
|
||||
</div>
|
||||
<h4>Sample Code</h4>
|
||||
<div>
|
||||
<pre>#include <<a href="../headers/facilities/overload.html">boost/preprocessor/facilities/overload.hpp</a>><br>#include <<a
|
||||
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
|
||||
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
|
||||
href="add.html">BOOST_PP_ADD</a>(number1,number2)<br><br>#if !BOOST_PP_VARIADICS_MSVC<br><br>#define MACRO_ADD_NUMBERS(...) <a
|
||||
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
|
||||
href="cat.html">BOOST_PP_CAT</a>(<a href="overload.html">BOOST_PP_OVERLOAD</a>(MACRO_,__VA_ARGS__)(__VA_ARGS__),<a
|
||||
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>
|
||||
</div>
|
||||
<h4>Sample Code</h4>
|
||||
<div>
|
||||
<pre>#include <<a href="../headers/facilities/overload.html">boost/preprocessor/facilities/overload.hpp</a>><br>#include <<a 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 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 href="add.html">BOOST_PP_ADD</a>(number1,number2)<br><br>#define MACRO_ADD_NUMBERS(...) <a href="overload.html">BOOST_PP_OVERLOAD</a>(MACRO_,__VA_ARGS__)(__VA_ARGS__)<br><br>// or for Visual C++<br><br>#define MACRO_ADD_NUMBERS(...) \<br> <a href="cat.html">BOOST_PP_CAT</a>(<a href="overload.html">BOOST_PP_OVERLOAD</a>(MACRO_,__VA_ARGS__)(__VA_ARGS__),<a href="empty.html">BOOST_PP_EMPTY</a>())<br><br>MACRO_ADD_NUMBERS(5) // output is 15<br>MACRO_ADD_NUMBERS(3,6) // output is 9<br></pre>
|
||||
</div>
|
||||
<hr size="1">
|
||||
<div style="margin-left: 0px;"> <i></i><i><EFBFBD> Copyright Edward Diener 2011,2013</i> </div>
|
||||
<div style="margin-left: 0px;">
|
||||
<hr size="1">
|
||||
<div style="margin-left: 0px;"> <i></i><i><EFBFBD> Copyright Edward Diener 2011,2013,2016</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>
|
||||
(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>
|
||||
</html>
|
||||
|
||||
</body></html>
|
||||
@ -1,40 +1,37 @@
|
||||
<html>
|
||||
<head>
|
||||
<meta content="text/html; charset=windows-1252" http-equiv="content-type">
|
||||
<title>variadic_macros.html</title>
|
||||
<link rel="stylesheet" type="text/css" href="../styles.css">
|
||||
<link rel="stylesheet" type="text/css" href="../styles.css">
|
||||
<style>
|
||||
u { font-weight: normal; text-decoration: none; }
|
||||
</style>
|
||||
</head>
|
||||
<body>
|
||||
<h4>Variadic Macros</h4>
|
||||
<div> Variadic macros are supported by a number of compilers.
|
||||
They are
|
||||
macros of the form:
|
||||
</div>
|
||||
<div class="code">
|
||||
<div> Variadic macros are supported by a number of compilers. They are
|
||||
macros of the form: </div>
|
||||
<div class="code">
|
||||
<pre>#define SOME_MACRO(ZeroOrMoreParameters,...) macro expansion possible specifying __VA_ARGS__</pre>
|
||||
</div>
|
||||
<div> The '...' in the parameter list represents the variadic
|
||||
data when the macro is invoked and the __VA_ARGS__ in the expansion
|
||||
represents the variadic data in the expansion of the macro. Variadic
|
||||
data is of the form of 1 or more preprocessor tokens separated by
|
||||
commas.<br>
|
||||
<div> The '...' in the parameter list represents the variadic data when the
|
||||
macro is invoked and the __VA_ARGS__ in the expansion represents the
|
||||
variadic data in the expansion of the macro. Variadic data is of the form
|
||||
of 1 or more preprocessor tokens separated by commas.<br>
|
||||
<br>
|
||||
The '...' must be the last parameter in the macro definition and there
|
||||
may be 0 or more non-variadic parameters preceding it.<br>
|
||||
The '...' must be the last parameter in the macro definition and there may
|
||||
be 0 or more non-variadic parameters preceding it.<br>
|
||||
<br>
|
||||
In the expansion of the macro __VA_ARGS__ may be specified 0 or more
|
||||
times to represent the variadic data. The variadic data in the
|
||||
expansion is a comma separated list of preprocessor tokens representing
|
||||
the variadic data which the invoker of the macro enters as the last
|
||||
arguments to the macro.<br>
|
||||
In the expansion of the macro __VA_ARGS__ may be specified 0 or more times
|
||||
to represent the variadic data. The variadic data in the expansion is a
|
||||
comma separated list of preprocessor tokens representing the variadic data
|
||||
which the invoker of the macro enters as the last arguments to the macro.<br>
|
||||
</div>
|
||||
<h4>Example<u> - Creating and invoking a variadic macro.</u></h4>
|
||||
<div class="code">
|
||||
<div class="code">
|
||||
<pre>#define INITIALIZE_INT_ARRAY(array_name,...) \ <br> static int array_name[] = { __VA_ARGS__ }; \ <br> /**/<br><br> INITIALIZE_INT_ARRAY(myname,45,789,33510,9346,2)</pre>
|
||||
</div>
|
||||
<u> <span style="font-weight: bold;">Preprocessor
|
||||
<u> <span style="font-weight: bold;">Preprocessor
|
||||
Library Support<br>
|
||||
</span></u>
|
||||
<div>The library offers support for variadic macros for those
|
||||
@ -56,7 +53,15 @@
|
||||
When BOOST_PP_VARIADICS is 1, the library offers some extended
|
||||
functionality
|
||||
by using variadic macros, and also offers extended support for working
|
||||
with variadic data.<br>
|
||||
with variadic data.<br><br>
|
||||
<a name="vmvcquirk"></a>Visual C++ has a
|
||||
few quirks related to variadic macros which require the end-user to code
|
||||
slightly differently. When BOOST_PP_VARIADICS is 1 and Visual C++ is the
|
||||
compiler BOOST_PP_VARIADICS_MSVC is 1, else when BOOST_PP_VARIADICS is 1
|
||||
and Visual C++ is not the compiler BOOST_PP_VARIADICS_MSVC is 0. When
|
||||
BOOST_PP_VARIADICS is 0 then BOOST_PP_VARIADICS_MSVC is not defined.
|
||||
In this way the end-user, when using variadic macros, can test for the
|
||||
presence of Visual C++ as the compiler and code accordingly.<br>
|
||||
<br>
|
||||
Support for working with variadic
|
||||
data is largely centered on being able to convert variadic data to
|
||||
@ -64,7 +69,7 @@
|
||||
functionality for working with those Boost preprocessor library data
|
||||
types is much greater than that for working with variadic data directly.<br>
|
||||
</div>
|
||||
<a name="VNotation"></a>
|
||||
<a name="VNotation"></a>
|
||||
<h4>Notation For Variadic Macros<br>
|
||||
</h4>
|
||||
<div>In the documentation, headers which have variadic macros,
|
||||
@ -131,7 +136,7 @@
|
||||
use this variadic data reliably as arguments to other macros, one needs
|
||||
variadic macro support.<br>
|
||||
</div>
|
||||
<u style="font-weight: bold;"> Using a Tuple Instead of an Array<br>
|
||||
<u style="font-weight: bold;"> Using a Tuple Instead of an Array<br>
|
||||
</u>
|
||||
<div>An array as a preprocessor data type is a two-element tuple where the
|
||||
first element is the array size and the second element is a tuple which
|
||||
@ -144,7 +149,7 @@
|
||||
type is essentially obsolete for conforming C++ compilers. Only if your
|
||||
compiler does not support variadic macros is the preprocessor array data
|
||||
type still useful.</div>
|
||||
<u style="font-weight: bold;">Using Variadic Data</u>
|
||||
<u style="font-weight: bold;">Using Variadic Data</u>
|
||||
<div>Variadic data exists in the
|
||||
form of comma-separated preprocessor tokens. This is the case whether
|
||||
the variadic data comes from the __VA_ARGS__ of a variadic macro, from
|
||||
@ -169,7 +174,7 @@
|
||||
variadic data as a whole to variadic macros as the last parameter of
|
||||
the macro. However: <br>
|
||||
<br>
|
||||
<span style="font-weight: bold;">Attempting to pass
|
||||
<span style="font-weight: bold;">Attempting to pass
|
||||
variadic data as a
|
||||
whole directly into a non-variadic macro is not guaranteed to work and
|
||||
may fail.<br>
|
||||
@ -178,7 +183,7 @@
|
||||
of compilers, currently most notably Visual C++. Even passing variadic
|
||||
data as arguments to a non-variadic macro, when it is not represented
|
||||
in
|
||||
the form of __VA_ARGS__, may fail with certain compilers.<br>
|
||||
the form of<EFBFBD> __VA_ARGS__, may fail with certain compilers.<br>
|
||||
<br>
|
||||
What follows are very simple examples, showing how variadic data can be
|
||||
passed to a non-variadic macro.<br>
|
||||
@ -188,9 +193,9 @@
|
||||
<h4>Example<u> - Passing variadic data as a whole to a
|
||||
non-variadic
|
||||
macro. DO NOT DO.</u></h4>
|
||||
<div class="code">
|
||||
<div class="code">
|
||||
<pre>#define MACRO_ARG_2(x,y) BOOST_PP_ADD(x,y)<br>#define VAR_MACRO(...) __VA_ARGS__<br><br>/* The following should not be done and is not guaranteed to work with compilers. */<br><br><span
|
||||
style="font-weight: bold;"><span style="font-family: monospace;"></span></span>int xx = MACRO_ARG_2(VAR_MACRO(2,3));</pre>
|
||||
style="font-weight: bold;"><span style="font-family: monospace;"></span></span>int xx = MACRO_ARG_2(VAR_MACRO(2,3));</pre>
|
||||
</div>
|
||||
<div> There are two ways to pass variadic data to a non-variadic
|
||||
macro.
|
||||
@ -203,7 +208,7 @@ style="font-weight: bold;"><span style="font-family: monospace;"></span></span>i
|
||||
a
|
||||
non-variadic macro.<br>
|
||||
</u></h4>
|
||||
<div class="code">
|
||||
<div class="code">
|
||||
<pre>#define MACRO_ARG_2(x,y) BOOST_PP_ADD(x,y)<br>#define VAR_MACRO(...) __VA_ARGS__<br><br>/* The following will work correctly */<br><br>int xx = MACRO_ARG_2<br> (<br> BOOST_PP_VARIADIC_ELEM(0,VAR_MACRO(2,3)),<br> BOOST_PP_VARIADIC_ELEM(1,VAR_MACRO(2,3))<br> );</pre>
|
||||
</div>
|
||||
<div>The second way is to use a macro in the library called
|
||||
@ -215,7 +220,7 @@ style="font-weight: bold;"><span style="font-family: monospace;"></span></span>i
|
||||
BOOST_PP_OVERLOAD
|
||||
and on to a non-variadic macro.<br>
|
||||
</u></h4>
|
||||
<div class="code">
|
||||
<div class="code">
|
||||
<pre>#define MACRO_ARG_2(x,y) BOOST_PP_ADD(x,y)<br>#define VAR_MACRO(...) __VA_ARGS__<br><br>/* The following will work correctly */<br><br>int xx = BOOST_PP_OVERLOAD(MACRO_ARG_,VAR_MACRO(2,3))(VAR_MACRO(2,3));<br><br>/* For Visual C++ it is necessary to do this */<br><br>int xx = <br>BOOST_PP_CAT(BOOST_PP_OVERLOAD(MACRO_ARG_,VAR_MACRO(2,3))(VAR_MACRO(2,3)),BOOST_PP_EMPTY());</pre>
|
||||
</div>
|
||||
<br>
|
||||
@ -230,27 +235,28 @@ style="font-weight: bold;"><span style="font-family: monospace;"></span></span>i
|
||||
</div>
|
||||
<b>See</b> <b>Also</b><br>
|
||||
<ul>
|
||||
<li><a href="../ref/variadics.html">BOOST_PP_VARIADICS</a></li>
|
||||
<li><a href="../headers/tuple.html">Tuple Macros</a><br>
|
||||
<li><a href="../ref/variadics.html">BOOST_PP_VARIADICS</a></li>
|
||||
<li><a href="../headers/tuple.html">Tuple Macros</a><br>
|
||||
</li>
|
||||
<li><a href="../headers/variadic.html">Variadic
|
||||
<li><a href="../headers/variadic.html">Variadic
|
||||
Macros<br>
|
||||
</a></li>
|
||||
<li><a href="../ref/array_enum.html">BOOST_PP_ARRAY_ENUM</a></li>
|
||||
<li><a href="../ref/list_enum_r.html">BOOST_PP_LIST_ENUM</a></li>
|
||||
<li><a href="../ref/seq_enum.html">BOOST_PP_SEQ_ENUM</a></li>
|
||||
<li><a href="../ref/tuple_enum.html">BOOST_PP_TUPLE_ENUM</a></li>
|
||||
<li><a href="../ref/overload.html">BOOST_PP_OVERLOAD</a></li>
|
||||
<li><a href="../ref/array_enum.html">BOOST_PP_ARRAY_ENUM</a></li>
|
||||
<li><a href="../ref/list_enum_r.html">BOOST_PP_LIST_ENUM</a></li>
|
||||
<li><a href="../ref/seq_enum.html">BOOST_PP_SEQ_ENUM</a></li>
|
||||
<li><a href="../ref/tuple_enum.html">BOOST_PP_TUPLE_ENUM</a></li>
|
||||
<li><a href="../ref/overload.html">BOOST_PP_OVERLOAD</a></li>
|
||||
</ul>
|
||||
<hr size="1">
|
||||
<div style="margin-left: 0px;"> <i><EFBFBD> Copyright
|
||||
<hr size="1">
|
||||
<div style="margin-left: 0px;"> <i><EFBFBD> Copyright
|
||||
Edward Diener
|
||||
2011,2013</i> </div>
|
||||
<div style="margin-left: 0px;">
|
||||
2011,2013,2016</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>
|
||||
(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>
|
||||
</html>
|
||||
|
||||
|
||||
</body></html>
|
||||
@ -73,7 +73,7 @@
|
||||
# define BOOST_PP_VARIADICS_MSVC 0
|
||||
# if !defined BOOST_PP_VARIADICS
|
||||
# /* variadic support explicitly disabled for all untested compilers */
|
||||
# if defined __GCCXML__ || defined __CUDACC__ || defined __PATHSCALE__ || defined __DMC__ || defined __CODEGEARC__ || defined __BORLANDC__ || defined __MWERKS__ || ( defined __SUNPRO_CC && __SUNPRO_CC < 0x5130 ) || defined __HP_aCC && !defined __EDG__ || defined __MRC__ || defined __SC__ || defined __IBMCPP__ || defined __PGI
|
||||
# if defined __GCCXML__ || defined __CUDACC__ || defined __PATHSCALE__ || defined __DMC__ || defined __CODEGEARC__ || defined __BORLANDC__ || defined __MWERKS__ || ( defined __SUNPRO_CC && __SUNPRO_CC < 0x5120 ) || defined __HP_aCC && !defined __EDG__ || defined __MRC__ || defined __SC__ || defined __IBMCPP__ || defined __PGI
|
||||
# define BOOST_PP_VARIADICS 0
|
||||
# /* VC++ (C/C++) */
|
||||
# elif defined _MSC_VER && _MSC_VER >= 1400 && (!defined __EDG__ || defined(__INTELLISENSE__)) && !defined __clang__
|
||||
|
||||
Reference in New Issue
Block a user