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"> 4<head> 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: Integral Constant</title> 8<link rel="stylesheet" href="../style.css" type="text/css" /> 9</head> 10<body class="docframe refmanual"> 11<table class="header"><tr class="header"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./data-types-concepts.html" class="navigation-link">Prev</a> <a href="./numeric.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group">Back Along</span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./data-types-concepts.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="./data-types.html" class="navigation-link">Data Types</a> / <a href="./data-types-concepts.html" class="navigation-link">Concepts</a> / <a href="./integral-constant.html" class="navigation-link">Integral Constant</a></td> 13</tr></table><div class="header-separator"></div> 14<div class="section" id="integral-constant"> 15<h1><a class="toc-backref" href="./data-types-concepts.html#id1574">Integral Constant</a></h1> 16<div class="section" id="id1217"> 17<h3><a class="subsection-title" href="#description" name="description">Description</a></h3> 18<p>An <a class="reference internal" href="./integral-constant.html">Integral Constant</a> is a holder class for a compile-time value of an 19integral type. Every <a class="reference internal" href="./integral-constant.html">Integral Constant</a> is also a nullary <a class="reference internal" href="./metafunction.html">Metafunction</a>, 20returning itself. An integral constant <em>object</em> is implicitly convertible to the 21corresponding run-time value of the wrapped integral type.</p> 22</div> 23<div class="section" id="id1218"> 24<h3><a class="subsection-title" href="#expression-requirements" name="expression-requirements">Expression requirements</a></h3> 25<p>In the following table and subsequent specifications, <tt class="literal"><span class="pre">n</span></tt> is a model of <a class="reference internal" href="./integral-constant.html">Integral Constant</a>.</p> 26<table border="1" class="docutils table"> 27<colgroup> 28<col width="35%" /> 29<col width="39%" /> 30<col width="27%" /> 31</colgroup> 32<thead valign="bottom"> 33<tr><th class="head">Expression</th> 34<th class="head">Type</th> 35<th class="head">Complexity</th> 36</tr> 37</thead> 38<tbody valign="top"> 39<tr><td><tt class="literal"><span class="pre">n::tag</span></tt></td> 40<td><tt class="literal"><span class="pre">integral_c_tag</span></tt></td> 41<td>Constant time.</td> 42</tr> 43<tr><td><tt class="literal"><span class="pre">n::<a href="./value-type.html" class="identifier">value_type</a></span></tt></td> 44<td>An integral type</td> 45<td>Constant time.</td> 46</tr> 47<tr><td><tt class="literal"><span class="pre">n::value</span></tt></td> 48<td>An integral constant expression</td> 49<td>Constant time.</td> 50</tr> 51<tr><td><tt class="literal"><span class="pre">n::type</span></tt></td> 52<td><a class="reference internal" href="./integral-constant.html">Integral Constant</a></td> 53<td>Constant time.</td> 54</tr> 55<tr><td><tt class="literal"><span class="pre"><a href="./next.html" class="identifier">next</a><n>::type</span></tt></td> 56<td><a class="reference internal" href="./integral-constant.html">Integral Constant</a></td> 57<td>Constant time.</td> 58</tr> 59<tr><td><tt class="literal"><span class="pre"><a href="./prior.html" class="identifier">prior</a><n>::type</span></tt></td> 60<td><a class="reference internal" href="./integral-constant.html">Integral Constant</a></td> 61<td>Constant time.</td> 62</tr> 63<tr><td><tt class="literal"><span class="pre">n::<a href="./value-type.html" class="identifier">value_type</a></span> <span class="pre">const</span> <span class="pre">c</span> <span class="pre">=</span> <span class="pre">n()</span></tt></td> 64<td> </td> 65<td>Constant time.</td> 66</tr> 67</tbody> 68</table> 69</div> 70<div class="section" id="id1219"> 71<h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> 72<table border="1" class="docutils table"> 73<colgroup> 74<col width="40%" /> 75<col width="60%" /> 76</colgroup> 77<thead valign="bottom"> 78<tr><th class="head">Expression</th> 79<th class="head">Semantics</th> 80</tr> 81</thead> 82<tbody valign="top"> 83<tr><td><tt class="literal"><span class="pre">n::tag</span></tt></td> 84<td><tt class="literal"><span class="pre">n</span></tt>'s tag type; <tt class="literal"><span class="pre">n::tag::value</span></tt> is <tt class="literal"><span class="pre">n</span></tt>'s 85<em>conversion rank</em>.</td> 86</tr> 87<tr><td><tt class="literal"><span class="pre">n::<a href="./value-type.html" class="identifier">value_type</a></span></tt></td> 88<td>A cv-unqualified type of <tt class="literal"><span class="pre">n::value</span></tt>.</td> 89</tr> 90<tr><td><tt class="literal"><span class="pre">n::value</span></tt></td> 91<td>The value of the wrapped integral constant.</td> 92</tr> 93<tr><td><tt class="literal"><span class="pre">n::type</span></tt></td> 94<td><tt class="literal"><span class="pre">is_same<n::type,n>::value</span> <span class="pre">==</span> <span class="pre">true</span></tt>.</td> 95</tr> 96<tr><td><tt class="literal"><span class="pre"><a href="./next.html" class="identifier">next</a><n>::type</span></tt></td> 97<td>An <a class="reference internal" href="./integral-constant.html">Integral Constant</a> <tt class="literal"><span class="pre">c</span></tt> of type <tt class="literal"><span class="pre">n::<a href="./value-type.html" class="identifier">value_type</a></span></tt> 98such that <tt class="literal"><span class="pre">c::value</span> <span class="pre">==</span> <span class="pre">n::value</span> <span class="pre">+</span> <span class="pre">1</span></tt>.</td> 99</tr> 100<tr><td><tt class="literal"><span class="pre"><a href="./prior.html" class="identifier">prior</a><n>::type</span></tt></td> 101<td>An <a class="reference internal" href="./integral-constant.html">Integral Constant</a> <tt class="literal"><span class="pre">c</span></tt> of type <tt class="literal"><span class="pre">n::<a href="./value-type.html" class="identifier">value_type</a></span></tt> 102such that <tt class="literal"><span class="pre">c::value</span> <span class="pre">==</span> <span class="pre">n::value</span> <span class="pre">-</span> <span class="pre">1</span></tt>.</td> 103</tr> 104<tr><td><tt class="literal"><span class="pre">n::<a href="./value-type.html" class="identifier">value_type</a></span> <span class="pre">const</span> <span class="pre">c</span> <span class="pre">=</span> <span class="pre">n()</span></tt></td> 105<td><tt class="literal"><span class="pre">c</span> <span class="pre">==</span> <span class="pre">n::value</span></tt>.</td> 106</tr> 107</tbody> 108</table> 109</div> 110<div class="section" id="id1220"> 111<h3><a class="subsection-title" href="#models" name="models">Models</a></h3> 112<ul class="simple"> 113<li><a class="reference internal" href="./bool.html">bool_</a></li> 114<li><a class="reference internal" href="./int.html">int_</a></li> 115<li><a class="reference internal" href="./long.html">long_</a></li> 116<li><a class="reference internal" href="./char.html">char_</a></li> 117<li><a class="reference internal" href="./integral-c.html">integral_c</a></li> 118</ul> 119</div> 120<div class="section" id="id1221"> 121<h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> 122<p><a class="reference internal" href="./data-types.html">Data Types</a>, <a class="reference internal" href="./integral-sequence-wrapper.html">Integral Sequence Wrapper</a>, <a class="reference internal" href="./integral-c.html">integral_c</a></p> 123</div> 124</div> 125 126<div class="footer-separator"></div> 127<table class="footer"><tr class="footer"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./data-types-concepts.html" class="navigation-link">Prev</a> <a href="./numeric.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group">Back Along</span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./data-types-concepts.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> 128<td><div class="copyright-footer"><div class="copyright">Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams</div> 129Distributed under the Boost Software License, Version 1.0. (See accompanying 130file 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> 131</html> 132