55 lines
4.2 KiB
HTML
55 lines
4.2 KiB
HTML
<html>
|
||
<head>
|
||
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
|
||
<title>Macro BOOST_VMD_IDENTITY</title>
|
||
<link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css">
|
||
<meta name="generator" content="DocBook XSL Stylesheets V1.79.1">
|
||
<link rel="home" href="index.html" title="Chapter 1. The Variadic Macro Data Library 1.10">
|
||
<link rel="up" href="header/boost/vmd/identity_hpp.html" title="Header <boost/vmd/identity.hpp>">
|
||
<link rel="prev" href="header/boost/vmd/identity_hpp.html" title="Header <boost/vmd/identity.hpp>">
|
||
<link rel="next" href="BOOST_VMD_IDENTITY_RESULT.html" title="Macro BOOST_VMD_IDENTITY_RESULT">
|
||
</head>
|
||
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
|
||
<table cellpadding="2" width="100%"><tr>
|
||
<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../boost.png"></td>
|
||
<td align="center"><a href="../../../../index.html">Home</a></td>
|
||
<td align="center"><a href="../../../../libs/libraries.htm">Libraries</a></td>
|
||
<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
|
||
<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
|
||
<td align="center"><a href="../../../../more/index.htm">More</a></td>
|
||
</tr></table>
|
||
<hr>
|
||
<div class="spirit-nav">
|
||
<a accesskey="p" href="header/boost/vmd/identity_hpp.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="header/boost/vmd/identity_hpp.html"><img src="../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="index.html"><img src="../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="BOOST_VMD_IDENTITY_RESULT.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a>
|
||
</div>
|
||
<div class="refentry">
|
||
<a name="BOOST_VMD_IDENTITY"></a><div class="titlepage"></div>
|
||
<div class="refnamediv">
|
||
<h2><span class="refentrytitle">Macro BOOST_VMD_IDENTITY</span></h2>
|
||
<p>BOOST_VMD_IDENTITY — Macro which expands to its argument when invoked with any number of parameters. </p>
|
||
</div>
|
||
<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
|
||
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="header/boost/vmd/identity_hpp.html" title="Header <boost/vmd/identity.hpp>">boost/vmd/identity.hpp</a>>
|
||
|
||
</span>BOOST_VMD_IDENTITY(item)</pre></div>
|
||
<div class="refsect1">
|
||
<a name="idm45711064961904"></a><h2>Description</h2>
|
||
<p>item = any single argument</p>
|
||
<p>When BOOST_VMD_IDENTITY(item) is subsequently invoked with any number of parameters it expands to 'item'. Subsequently invoking the macro is done as 'BOOST_VMD_IDENTITY(item)(zero_or_more_arguments)'.</p>
|
||
<p>The macro is equivalent to the Boost PP macro BOOST_PP_IDENTITY(item) with the difference being that BOOST_PP_IDENTITY(item) is always invoked with no arguments, as in 'BOOST_VMD_IDENTITY(item)()' whereas BOOST_VMD_IDENTITY can be invoked with any number of arguments.</p>
|
||
<p>The macro is meant to be used in BOOST_PP_IF and BOOST_PP_IIF statements when only one of the clauses needs to be invoked with calling another macro and the other is meant to return an 'item'.</p>
|
||
<p>returns = the macro as 'BOOST_VMD_IDENTITY(item)', when invoked with any number of parameters as in '(zero_or_more_arguments)', returns 'item'. The macro itself returns 'item BOOST_VMD_EMPTY'. </p>
|
||
</div>
|
||
</div>
|
||
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
|
||
<td align="left"></td>
|
||
<td align="right"><div class="copyright-footer">Copyright © 2010-2017 Tropic Software
|
||
East Inc</div></td>
|
||
</tr></table>
|
||
<hr>
|
||
<div class="spirit-nav">
|
||
<a accesskey="p" href="header/boost/vmd/identity_hpp.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="header/boost/vmd/identity_hpp.html"><img src="../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="index.html"><img src="../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="BOOST_VMD_IDENTITY_RESULT.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a>
|
||
</div>
|
||
</body>
|
||
</html>
|