<?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: less</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="./comparisons.html" class="navigation-link">Prev</a> <a href="./less-equal.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group">Back <a href="./less-equal.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./comparisons.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="./comparisons.html" class="navigation-link">Comparisons</a> / <a href="./less.html" class="navigation-link">less</a></td> </tr></table><div class="header-separator"></div> <div class="section" id="less"> <h1><a class="toc-backref" href="./comparisons.html#id1526">less</a></h1> <div class="section" id="id1014"> <h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3> <pre class="literal-block"> template< typename T1 , typename T2 > struct <a href="./less.html" class="identifier">less</a> { typedef <em>unspecified</em> type; }; </pre> </div> <div class="section" id="id1015"> <h3><a class="subsection-title" href="#description" name="description">Description</a></h3> <p>Returns a true-valued <a class="reference internal" href="./integral-constant.html">Integral Constant</a> if <tt class="literal"><span class="pre">T1</span></tt> is less than <tt class="literal"><span class="pre">T2</span></tt>.</p> </div> <div class="section" id="id1016"> <h3><a class="subsection-title" href="#header" name="header">Header</a></h3> <pre class="literal-block"> #include <<a href="../../../../boost/mpl/less.hpp" class="header">boost/mpl/less.hpp</a>> #include <<a href="../../../../boost/mpl/comparison.hpp" class="header">boost/mpl/comparison.hpp</a>> </pre> </div> <div class="section" id="id1017"> <h3><a class="subsection-title" href="#model-of" name="model-of">Model of</a></h3> <p><a class="reference internal" href="./numeric-metafunction.html">Numeric Metafunction</a></p> </div> <div class="section" id="id1018"> <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">T1</span></tt>, <tt class="literal"><span class="pre">T2</span></tt></td> <td><a class="reference internal" href="./integral-constant.html">Integral Constant</a></td> <td>Operation's arguments.</td> </tr> </tbody> </table> <p>[<em>Note:</em> The requirements listed in this specification are the ones imposed by the default implementation. See <a class="reference internal" href="./numeric-metafunction.html">Numeric Metafunction</a> concept for the details on how to provide an implementation for a user-defined numeric type that does not satisfy the <a class="reference internal" href="./integral-constant.html">Integral Constant</a> requirements. — <em>end note</em>]</p> </div> <div class="section" id="id1019"> <h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> <p>For any <a class="reference internal" href="./integral-constant.html">Integral Constant</a>s <tt class="literal"><span class="pre">c1</span></tt> and <tt class="literal"><span class="pre">c2</span></tt>:</p> <pre class="literal-block"> typedef <a href="./less.html" class="identifier">less</a><c1,c2>::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"><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"> typedef <a href="./bool.html" class="identifier">bool_</a>< (c1::value < c2::value) > r; </pre> </td> </tr> </tbody> </table> <!-- .......................................................................... --> <pre class="literal-block"> typedef <a href="./less.html" class="identifier">less</a><c1,c2> 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="./less.html" class="identifier">less</a><c1,c2>::type {}; </pre> </td> </tr> </tbody> </table> </div> <div class="section" id="id1020"> <h3><a class="subsection-title" href="#complexity" name="complexity">Complexity</a></h3> <p>Amortized constant time.</p> </div> <div class="section" id="id1021"> <h3><a class="subsection-title" href="#example" name="example">Example</a></h3> <pre class="literal-block"> <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( <a href="./less.html" class="identifier">less</a>< <a href="./int.html" class="identifier">int_</a><0>, <a href="./int.html" class="identifier">int_</a><10> > )); <a href="./assert-not.html" class="identifier">BOOST_MPL_ASSERT_NOT</a>(( <a href="./less.html" class="identifier">less</a>< <a href="./long.html" class="identifier">long_</a><10>, <a href="./int.html" class="identifier">int_</a><0> > )); <a href="./assert-not.html" class="identifier">BOOST_MPL_ASSERT_NOT</a>(( <a href="./less.html" class="identifier">less</a>< <a href="./long.html" class="identifier">long_</a><10>, <a href="./int.html" class="identifier">int_</a><10> > )); </pre> </div> <div class="section" id="id1022"> <h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> <p><a class="reference internal" href="./comparisons.html">Comparisons</a>, <a class="reference internal" href="./numeric-metafunction.html">Numeric Metafunction</a>, <a class="reference internal" href="./numeric-cast.html">numeric_cast</a>, <a class="reference internal" href="./less-equal.html">less_equal</a>, <a class="reference internal" href="./greater.html">greater</a>, <a class="reference internal" href="./equal.html">equal</a></p> <!-- Metafunctions/Comparisons//less_equal |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="./comparisons.html" class="navigation-link">Prev</a> <a href="./less-equal.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group">Back <a href="./less-equal.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./comparisons.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. 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