1 <?xml version=
"1.0" encoding=
"utf-8" ?>
2 <!DOCTYPE html PUBLIC
"-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
3 <html xmlns=
"http://www.w3.org/1999/xhtml" xml:
lang=
"en" lang=
"en">
5 <meta http-equiv=
"Content-Type" content=
"text/html; charset=utf-8" />
6 <meta name=
"generator" content=
"Docutils 0.7: http://docutils.sourceforge.net/" />
7 <title>The MPL Reference Manual: always
</title>
8 <link rel=
"stylesheet" href=
"../style.css" type=
"text/css" />
10 <body class=
"docframe refmanual">
11 <table class=
"header"><tr class=
"header"><td class=
"header-group navigation-bar"><span class=
"navigation-group"><a href=
"./identity.html" class=
"navigation-link">Prev
</a> <a href=
"./inherit.html" class=
"navigation-link">Next
</a></span><span class=
"navigation-group-separator"> |
</span><span class=
"navigation-group"><a href=
"./identity.html" class=
"navigation-link">Back
</a> <a href=
"./inherit.html" class=
"navigation-link">Along
</a></span><span class=
"navigation-group-separator"> |
</span><span class=
"navigation-group"><a href=
"./miscellaneous.html" class=
"navigation-link">Up
</a> <a href=
"../refmanual.html" class=
"navigation-link">Home
</a></span><span class=
"navigation-group-separator"> |
</span><span class=
"navigation-group"><a href=
"./refmanual_toc.html" class=
"navigation-link">Full TOC
</a></span></td>
12 <td class=
"header-group page-location"><a href=
"../refmanual.html" class=
"navigation-link">Front Page
</a> /
<a href=
"./metafunctions.html" class=
"navigation-link">Metafunctions
</a> /
<a href=
"./miscellaneous.html" class=
"navigation-link">Miscellaneous
</a> /
<a href=
"./always.html" class=
"navigation-link">always
</a></td>
13 </tr></table><div class=
"header-separator"></div>
14 <div class=
"section" id=
"always">
15 <h1><a class=
"toc-backref" href=
"./miscellaneous.html#id1565">always
</a></h1>
16 <div class=
"section" id=
"id1155">
17 <h3><a class=
"subsection-title" href=
"#synopsis" name=
"synopsis">Synopsis
</a></h3>
18 <pre class=
"literal-block">
22 struct
<a href=
"./always.html" class=
"identifier">always
</a>
24 //
<em>unspecified
</em>
29 <div class=
"section" id=
"id1156">
30 <h3><a class=
"subsection-title" href=
"#description" name=
"description">Description
</a></h3>
31 <p><tt class=
"literal"><span class=
"pre"><a href=
"./always.html" class=
"identifier">always
</a><X
></span></tt> specialization is a variadic
<a class=
"reference internal" href=
"./metafunction-class.html">Metafunction Class
</a> always returning the
32 same type,
<tt class=
"literal"><span class=
"pre">X
</span></tt>, regardless of the number and types of passed arguments.
</p>
34 <div class=
"section" id=
"id1157">
35 <h3><a class=
"subsection-title" href=
"#header" name=
"header">Header
</a></h3>
36 <pre class=
"literal-block">
37 #include
<<a href=
"../../../../boost/mpl/always.hpp" class=
"header">boost/mpl/always.hpp
</a>>
40 <div class=
"section" id=
"id1158">
41 <h3><a class=
"subsection-title" href=
"#model-of" name=
"model-of">Model of
</a></h3>
42 <p><a class=
"reference internal" href=
"./metafunction-class.html">Metafunction Class
</a></p>
44 <div class=
"section" id=
"id1159">
45 <h3><a class=
"subsection-title" href=
"#parameters" name=
"parameters">Parameters
</a></h3>
46 <table border=
"1" class=
"docutils table">
52 <thead valign=
"bottom">
53 <tr><th class=
"head">Parameter
</th>
54 <th class=
"head">Requirement
</th>
55 <th class=
"head">Description
</th>
59 <tr><td><tt class=
"literal"><span class=
"pre">X
</span></tt></td>
61 <td>A type to be returned.
</td>
66 <div class=
"section" id=
"id1160">
67 <h3><a class=
"subsection-title" href=
"#expression-semantics" name=
"expression-semantics">Expression semantics
</a></h3>
68 <p>For an arbitrary type
<tt class=
"literal"><span class=
"pre">x
</span></tt>:
</p>
69 <pre class=
"literal-block">
70 typedef
<a href=
"./always.html" class=
"identifier">always
</a><x
> f;
72 <table class=
"docutils field-list" frame=
"void" rules=
"none">
73 <col class=
"field-name" />
74 <col class=
"field-body" />
76 <tr class=
"field"><th class=
"field-name">Return type:
</th><td class=
"field-body"><p class=
"first"><a class=
"reference internal" href=
"./metafunction-class.html">Metafunction Class
</a>.
</p>
79 <tr class=
"field"><th class=
"field-name">Semantics:
</th><td class=
"field-body"><p class=
"first">Equivalent to
</p>
80 <pre class=
"last literal-block">
81 struct f :
<a href=
"./bind.html" class=
"identifier">bind
</a>< <a href=
"./identity.html" class=
"identifier">identity
</a><<a href=
"./placeholders.html" class=
"identifier">_1
</a>>, x
> {};
88 <div class=
"section" id=
"id1161">
89 <h3><a class=
"subsection-title" href=
"#example" name=
"example">Example
</a></h3>
90 <pre class=
"literal-block">
91 typedef
<a href=
"./always.html" class=
"identifier">always
</a><<a href=
"./bool.html" class=
"identifier">true_
</a>> always_true;
93 <a href=
"./assert.html" class=
"identifier">BOOST_MPL_ASSERT
</a>((
<a href=
"./apply.html" class=
"identifier">apply
</a>< always_true,
<a href=
"./bool.html" class=
"identifier">false_
</a>> ));
94 <a href=
"./assert.html" class=
"identifier">BOOST_MPL_ASSERT
</a>((
<a href=
"./apply.html" class=
"identifier">apply
</a>< always_true,
<a href=
"./bool.html" class=
"identifier">false_
</a>,
<a href=
"./bool.html" class=
"identifier">false_
</a> > ));
95 <a href=
"./assert.html" class=
"identifier">BOOST_MPL_ASSERT
</a>((
<a href=
"./apply.html" class=
"identifier">apply
</a>< always_true,
<a href=
"./bool.html" class=
"identifier">false_
</a>,
<a href=
"./bool.html" class=
"identifier">false_
</a>,
<a href=
"./bool.html" class=
"identifier">false_
</a> > ));
98 <div class=
"section" id=
"id1162">
99 <h3><a class=
"subsection-title" href=
"#see-also" name=
"see-also">See also
</a></h3>
100 <p><a class=
"reference internal" href=
"./metafunctions.html">Metafunctions
</a>,
<a class=
"reference internal" href=
"./metafunction-class.html">Metafunction Class
</a>,
<a class=
"reference internal" href=
"./identity.html">identity
</a>,
<a class=
"reference internal" href=
"./bind.html">bind
</a>,
<a class=
"reference internal" href=
"./apply.html">apply
</a></p>
101 <!-- Metafunctions/Miscellaneous//inherit |30 -->
105 <div class=
"footer-separator"></div>
106 <table class=
"footer"><tr class=
"footer"><td class=
"header-group navigation-bar"><span class=
"navigation-group"><a href=
"./identity.html" class=
"navigation-link">Prev
</a> <a href=
"./inherit.html" class=
"navigation-link">Next
</a></span><span class=
"navigation-group-separator"> |
</span><span class=
"navigation-group"><a href=
"./identity.html" class=
"navigation-link">Back
</a> <a href=
"./inherit.html" class=
"navigation-link">Along
</a></span><span class=
"navigation-group-separator"> |
</span><span class=
"navigation-group"><a href=
"./miscellaneous.html" class=
"navigation-link">Up
</a> <a href=
"../refmanual.html" class=
"navigation-link">Home
</a></span><span class=
"navigation-group-separator"> |
</span><span class=
"navigation-group"><a href=
"./refmanual_toc.html" class=
"navigation-link">Full TOC
</a></span></td>
107 <td><div class=
"copyright-footer"><div class=
"copyright">Copyright ©
2001-
2009 Aleksey Gurtovoy and David Abrahams
</div>
108 Distributed under the Boost Software License, Version
1.0. (See accompanying
109 file LICENSE_1_0.txt or copy at
<a class=
"reference external" href=
"http://www.boost.org/LICENSE_1_0.txt" target=
"_top">http://www.boost.org/LICENSE_1_0.txt
</a>)
</div></td></tr></table></body>