1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5<title>Struct template constructible_with_allocator_suffix</title> 6<link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css"> 7<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 8<link rel="home" href="../../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> 9<link rel="up" href="../../boost_container_header_reference.html#header.boost.container.uses_allocator_hpp" title="Header <boost/container/uses_allocator.hpp>"> 10<link rel="prev" href="construc_idm45641208075360.html" title="Struct template constructible_with_allocator_prefix"> 11<link rel="next" href="uses_allocator.html" title="Struct template uses_allocator"> 12</head> 13<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 14<table cellpadding="2" width="100%"><tr> 15<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../boost.png"></td> 16<td align="center"><a href="../../../../index.html">Home</a></td> 17<td align="center"><a href="../../../../libs/libraries.htm">Libraries</a></td> 18<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 19<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 20<td align="center"><a href="../../../../more/index.htm">More</a></td> 21</tr></table> 22<hr> 23<div class="spirit-nav"> 24<a accesskey="p" href="construc_idm45641208075360.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../boost_container_header_reference.html#header.boost.container.uses_allocator_hpp"><img src="../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="uses_allocator.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 25</div> 26<div class="refentry"> 27<a name="boost.container.construc_idm45641208064992"></a><div class="titlepage"></div> 28<div class="refnamediv"> 29<h2><span class="refentrytitle">Struct template constructible_with_allocator_suffix</span></h2> 30<p>boost::container::constructible_with_allocator_suffix</p> 31</div> 32<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 33<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="../../boost_container_header_reference.html#header.boost.container.uses_allocator_hpp" title="Header <boost/container/uses_allocator.hpp>">boost/container/uses_allocator.hpp</a>> 34 35</span><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> 36<span class="keyword">struct</span> <a class="link" href="construc_idm45641208064992.html" title="Struct template constructible_with_allocator_suffix">constructible_with_allocator_suffix</a> <span class="special">{</span> 37 38 <span class="comment">// public data members</span> 39 <span class="keyword">static</span> <span class="keyword">const</span> <span class="keyword">bool</span> <span class="identifier">value</span><span class="special">;</span> 40<span class="special">}</span><span class="special">;</span></pre></div> 41<div class="refsect1"> 42<a name="id-1.3.10.14.42.4.4"></a><h2>Description</h2> 43<p><span class="bold"><strong>Remark</strong></span>: if a specialization constructible_with_allocator_suffix<X>::value is true, indicates that T may be constructed with an allocator as its last constructor argument. Ideally, all constructors of T (including the copy and move constructors) should have a variant that accepts a final argument of allocator_type.</p> 44<p><span class="bold"><strong>Requires</strong></span>: if a specialization constructible_with_allocator_suffix<X>::value is true, T must have a nested type, allocator_type and at least one constructor for which allocator_type is the last parameter. If not all constructors of T can be called with a final allocator_type argument, and if T is used in a context where a container must call such a constructor, then the program is ill-formed.</p> 45<p><code class="computeroutput"> template <class T, class Allocator = allocator<T> > class Z { public: typedef Allocator allocator_type;</code></p> 46<p><code class="computeroutput"> // Default constructor with optional allocator suffix Z(const allocator_type& a = allocator_type());</code></p> 47<p><code class="computeroutput"> // Copy constructor and allocator-extended copy constructor Z(const Z& zz); Z(const Z& zz, const allocator_type& a); };</code></p> 48<p><code class="computeroutput">// Specialize trait for class template Z template <class T, class Allocator = allocator<T> > struct <a class="link" href="construc_idm45641208064992.html" title="Struct template constructible_with_allocator_suffix">constructible_with_allocator_suffix</a><Z<T,Allocator> > { static const bool value = true; }; </code></p> 49<p><span class="bold"><strong>Note</strong></span>: This trait is a workaround inspired by "N2554: The Scoped A Model (Rev 2)" (Pablo Halpern, 2008-02-29) to backport the scoped allocator model to C++03, as in C++03 there is no mechanism to detect if a type can be constructed from arbitrary arguments. Applications aiming portability with several compilers should always define this trait.</p> 50<p>In conforming C++11 compilers or compilers supporting SFINAE expressions (when BOOST_NO_SFINAE_EXPR is NOT defined), this trait is ignored and C++11 rules will be used to detect if a type should be constructed with suffix or prefix allocator arguments. </p> 51</div> 52</div> 53<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 54<td align="left"></td> 55<td align="right"><div class="copyright-footer">Copyright © 2009-2018 Ion Gaztanaga<p> 56 Distributed under the Boost Software License, Version 1.0. (See accompanying 57 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 58 </p> 59</div></td> 60</tr></table> 61<hr> 62<div class="spirit-nav"> 63<a accesskey="p" href="construc_idm45641208075360.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../boost_container_header_reference.html#header.boost.container.uses_allocator_hpp"><img src="../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="uses_allocator.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 64</div> 65</body> 66</html> 67
