<?xml version="1.0" encoding="utf-8" ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="generator" content="Docutils 0.6: http://docutils.sourceforge.net/" /> <title>The MPL Reference Manual: and_</title> <link rel="stylesheet" href="../style.css" type="text/css" /> </head> <body class="docframe refmanual"> <table class="header"><tr class="header"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./logical-operations.html" class="navigation-link">Prev</a> <a href="./or.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group">Back <a href="./or.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./logical-operations.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> <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="./logical-operations.html" class="navigation-link">Logical Operations</a> / <a href="./and.html" class="navigation-link">and_</a></td> </tr></table><div class="header-separator"></div> <div class="section" id="and"> <h1><a class="toc-backref" href="./logical-operations.html#id1533">and_</a></h1> <div class="section" id="id1068"> <h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3> <pre class="literal-block"> template< typename F1 , typename F2 <em>...</em> , typename F<em>n</em> = <em>unspecified</em> > struct <a href="./and.html" class="identifier">and_</a> { typedef <em>unspecified</em> type; }; </pre> </div> <div class="section" id="id1069"> <h3><a class="subsection-title" href="#description" name="description">Description</a></h3> <p>Returns the result of short-circuit <em>logical and</em> (<tt class="literal"><span class="pre">&&</span></tt>) operation on its arguments.</p> </div> <div class="section" id="id1070"> <h3><a class="subsection-title" href="#header" name="header">Header</a></h3> <pre class="literal-block"> #include <<a href="../../../../boost/mpl/and.hpp" class="header">boost/mpl/and.hpp</a>> #include <<a href="../../../../boost/mpl/logical.hpp" class="header">boost/mpl/logical.hpp</a>> </pre> </div> <div class="section" id="id1071"> <h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3> <table border="1" class="docutils table"> <colgroup> <col width="17%" /> <col width="30%" /> <col width="53%" /> </colgroup> <thead valign="bottom"> <tr><th class="head">Parameter</th> <th class="head">Requirement</th> <th class="head">Description</th> </tr> </thead> <tbody valign="top"> <tr><td><tt class="literal"><span class="pre">F1</span></tt>, <tt class="literal"><span class="pre">F2</span></tt>,... <tt class="literal"><span class="pre">Fn</span></tt></td> <td>Nullary <a class="reference internal" href="./metafunction.html">Metafunction</a></td> <td>Operation's arguments.</td> </tr> </tbody> </table> </div> <div class="section" id="id1072"> <h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> <p>For arbitrary nullary <a class="reference internal" href="./metafunction.html">Metafunction</a>s <tt class="literal"><span class="pre">f1</span></tt>, <tt class="literal"><span class="pre">f2</span></tt>,... <tt class="literal"><span class="pre">fn</span></tt>:</p> <pre class="literal-block"> typedef <a href="./and.html" class="identifier">and_</a><f1,f2,<em>...</em>,f<em>n</em>>::type r; </pre> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field"><th class="field-name">Return type:</th><td class="field-body"><a class="reference internal" href="./integral-constant.html">Integral Constant</a>.</td> </tr> <tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><tt class="literal"><span class="pre">r</span></tt> is <tt class="literal"><span class="pre"><a href="./bool.html" class="identifier">false_</a></span></tt> if either of <tt class="literal"><span class="pre">f1::type::value</span></tt>, <tt class="literal"><span class="pre">f2::type::value</span></tt>,... <tt class="literal"><span class="pre">fn::type::value</span></tt> expressions evaluates to <tt class="literal"><span class="pre">false</span></tt>, and <tt class="literal"><span class="pre"><a href="./bool.html" class="identifier">true_</a></span></tt> otherwise; guarantees left-to-right evaluation; the operands subsequent to the first <tt class="literal"><span class="pre">f</span></tt><em>i</em> metafunction that evaluates to <tt class="literal"><span class="pre">false</span></tt> are not evaluated.</td> </tr> </tbody> </table> <!-- .......................................................................... --> <pre class="literal-block"> typedef <a href="./and.html" class="identifier">and_</a><f1,f2,<em>...</em>,f<em>n</em>> r; </pre> <table class="docutils field-list" frame="void" rules="none"> <col class="field-name" /> <col class="field-body" /> <tbody valign="top"> <tr class="field"><th class="field-name">Return type:</th><td class="field-body"><p class="first"><a class="reference internal" href="./integral-constant.html">Integral Constant</a>.</p> </td> </tr> <tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><p class="first">Equivalent to</p> <pre class="last literal-block"> struct r : <a href="./and.html" class="identifier">and_</a><f1,f2,<em>...</em>,f<em>n</em>>::type {}; </pre> </td> </tr> </tbody> </table> </div> <div class="section" id="id1073"> <h3><a class="subsection-title" href="#example" name="example">Example</a></h3> <pre class="literal-block"> struct unknown; <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( <a href="./and.html" class="identifier">and_</a>< <a href="./bool.html" class="identifier">true_</a>,<a href="./bool.html" class="identifier">true_</a> > )); <a href="./assert-not.html" class="identifier">BOOST_MPL_ASSERT_NOT</a>(( <a href="./and.html" class="identifier">and_</a>< <a href="./bool.html" class="identifier">false_</a>,<a href="./bool.html" class="identifier">true_</a> > )); <a href="./assert-not.html" class="identifier">BOOST_MPL_ASSERT_NOT</a>(( <a href="./and.html" class="identifier">and_</a>< <a href="./bool.html" class="identifier">true_</a>,<a href="./bool.html" class="identifier">false_</a> > )); <a href="./assert-not.html" class="identifier">BOOST_MPL_ASSERT_NOT</a>(( <a href="./and.html" class="identifier">and_</a>< <a href="./bool.html" class="identifier">false_</a>,<a href="./bool.html" class="identifier">false_</a> > )); <a href="./assert-not.html" class="identifier">BOOST_MPL_ASSERT_NOT</a>(( <a href="./and.html" class="identifier">and_</a>< <a href="./bool.html" class="identifier">false_</a>,unknown > )); // OK <a href="./assert-not.html" class="identifier">BOOST_MPL_ASSERT_NOT</a>(( <a href="./and.html" class="identifier">and_</a>< <a href="./bool.html" class="identifier">false_</a>,unknown,unknown > )); // OK too </pre> </div> <div class="section" id="id1074"> <h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> <p><a class="reference internal" href="./metafunctions.html">Metafunctions</a>, <a class="reference internal" href="./logical-operations.html">Logical Operations</a>, <a class="reference internal" href="./or.html">or_</a>, <a class="reference internal" href="./not.html">not_</a></p> <!-- Metafunctions/Logical Operations//or_ |20 --> </div> </div> <div class="footer-separator"></div> <table class="footer"><tr class="footer"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./logical-operations.html" class="navigation-link">Prev</a> <a href="./or.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group">Back <a href="./or.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./logical-operations.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> <td><div class="copyright-footer"><div class="copyright">Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams</div> Distributed under the Boost Software License, Version 1.0. (See accompanying 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> </html>