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: empty_sequence</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="./views.html" class="navigation-link">Prev</a> <a href="./filter-view.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group">Back <a href="./filter-view.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./views.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="./sequences.html" class="navigation-link">Sequences</a> / <a href="./views.html" class="navigation-link">Views</a> / <a href="./empty-sequence.html" class="navigation-link">empty_sequence</a></td> 13</tr></table><div class="header-separator"></div> 14<div class="section" id="empty-sequence"> 15<h1><a class="toc-backref" href="./views.html#id1417">empty_sequence</a></h1> 16<div class="section" id="id120"> 17<h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3> 18<pre class="literal-block"> 19struct <a href="./empty-sequence.html" class="identifier">empty_sequence</a> 20{ 21 // <em>unspecified</em> 22 // <em>...</em> 23}; 24</pre> 25</div> 26<div class="section" id="id121"> 27<h3><a class="subsection-title" href="#description" name="description">Description</a></h3> 28<p>Represents a sequence containing no elements.</p> 29</div> 30<div class="section" id="id122"> 31<h3><a class="subsection-title" href="#header" name="header">Header</a></h3> 32<pre class="literal-block"> 33#include <<a href="../../../../boost/mpl/empty_sequence.hpp" class="header">boost/mpl/empty_sequence.hpp</a>> 34</pre> 35</div> 36<div class="section" id="id123"> 37<h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> 38<p>The semantics of an expression are defined only 39where they differ from, or are not defined in <a class="reference internal" href="./random-access-sequence.html">Random Access Sequence</a>.</p> 40<p>In the following table, <tt class="literal"><span class="pre">s</span></tt> is an instance of <tt class="literal"><span class="pre"><a href="./empty-sequence.html" class="identifier">empty_sequence</a></span></tt>.</p> 41<table border="1" class="docutils table"> 42<colgroup> 43<col width="34%" /> 44<col width="66%" /> 45</colgroup> 46<thead valign="bottom"> 47<tr><th class="head">Expression</th> 48<th class="head">Semantics</th> 49</tr> 50</thead> 51<tbody valign="top"> 52<tr><td><tt class="literal"><span class="pre"><a href="./empty-sequence.html" class="identifier">empty_sequence</a></span></tt></td> 53<td>An empty <a class="reference internal" href="./random-access-sequence.html">Random Access Sequence</a>.</td> 54</tr> 55<tr><td><tt class="literal"><span class="pre"><a href="./size.html" class="identifier">size</a><s>::type</span></tt></td> 56<td><tt class="literal"><span class="pre"><a href="./size.html" class="identifier">size</a><s>::value</span> <span class="pre">==</span> <span class="pre">0</span></tt>; see <a class="reference internal" href="./random-access-sequence.html">Random Access Sequence</a>.</td> 57</tr> 58</tbody> 59</table> 60</div> 61<div class="section" id="id124"> 62<h3><a class="subsection-title" href="#example" name="example">Example</a></h3> 63<pre class="literal-block"> 64typedef <a href="./begin.html" class="identifier">begin</a><<a href="./empty-sequence.html" class="identifier">empty_sequence</a>>::type first; 65typedef <a href="./end.html" class="identifier">end</a><<a href="./empty-sequence.html" class="identifier">empty_sequence</a>>::type last; 66 67<a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( is_same<first,last> )); 68<a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( <a href="./size.html" class="identifier">size</a><<a href="./empty-sequence.html" class="identifier">empty_sequence</a>>::value, ==, 0 ); 69 70typedef <a href="./transform-view.html" class="identifier">transform_view</a>< 71 <a href="./empty-sequence.html" class="identifier">empty_sequence</a> 72 , add_pointer<_> 73 > empty_view; 74 75<a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( <a href="./size.html" class="identifier">size</a><<a href="./empty-sequence.html" class="identifier">empty_sequence</a>>::value, ==, 0 ); 76</pre> 77</div> 78<div class="section" id="id125"> 79<h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> 80<p><a class="reference internal" href="./sequences.html">Sequences</a>, <a class="reference internal" href="./views.html">Views</a>, <a class="reference internal" href="./vector.html">vector</a>, <a class="reference internal" href="./list.html">list</a>, <a class="reference internal" href="./single-view.html">single_view</a></p> 81<!-- Sequences/Views//filter_view --> 82</div> 83</div> 84 85<div class="footer-separator"></div> 86<table class="footer"><tr class="footer"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./views.html" class="navigation-link">Prev</a> <a href="./filter-view.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group">Back <a href="./filter-view.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./views.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> 87<td><div class="copyright-footer"><div class="copyright">Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams</div> 88Distributed under the Boost Software License, Version 1.0. (See accompanying 89file 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> 90</html> 91