214 lines
14 KiB
HTML
214 lines
14 KiB
HTML
<!DOCTYPE html>
|
|
<html lang="zh" dir="ltr" class="client-nojs" xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh">
|
|
<head><meta http-equiv="x-ua-compatible" content="ie=edge">
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
|
<title>std::allocator_traits</title>
|
|
<link rel="stylesheet" href="ext.css" />
|
|
<link rel="stylesheet" href="site_modules.css" />
|
|
</head>
|
|
<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_memory_allocator_traits skin-cppreference2 action-view cpp-navbar">
|
|
<div id="cpp-content-base">
|
|
<div id="content"><a id="top"></a>
|
|
<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::</span>allocator_traits</h1>
|
|
<div id="bodyContent">
|
|
<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-memory.html">memory</a></span></div>
|
|
<div id="mw-content-text" lang="zh" dir="ltr" class="mw-content-ltr" xml:lang="zh">
|
|
<table class="t-dcl-begin">
|
|
<tbody>
|
|
<tr class="t-dsc-header">
|
|
<td>
|
|
<div>定义于头文件 <code><a href="cpp-header-memory.html"><memory></a></code></div>
|
|
</td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-cxx11">
|
|
<td>
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> Alloc <span class="sy1">></span><br />
|
|
<span class="kw1">struct</span> allocator_traits<span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td class="t-dcl-nopad"></td>
|
|
<td><span class="t-mark-rev t-since-cxx11">(C++11 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl-sep">
|
|
<td></td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p><code>allocator_traits</code> 类模板提供访问<a href="cpp-named_req-Allocator.html"><span style="font-style:italic">分配器</span> <span style="font-family: Georgia, 'DejaVu Serif', serif; font-style:italic">(Allocator)</span></a> 各种属性的标准化方式。标准容器和其他标准库组件通过此模板访问分配器，这使得能以任何类类型为分配器，只要用户提供的 <code>allocator_traits</code> 特化实现所有要求的功能。</p>
|
|
<p>默认的非特化 <code>allocator_traits</code> 含有下列成员：</p>
|
|
<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E7.B1.BB.E5.9E.8B">成员类型</span></h3>
|
|
<table class="t-dsc-begin">
|
|
<tr class="t-dsc-hitem">
|
|
<td>类型</td>
|
|
<td>定义</td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>allocator_type</code></td>
|
|
<td><span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc</span></span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>value_type</code></td>
|
|
<td><span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy4">::</span><span class="me2">value_type</span></span></span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>pointer</code></td>
|
|
<td>若存在则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy4">::</span><span class="me2">pointer</span></span></span> ，否则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">value_type<span class="sy2">*</span></span></span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>const_pointer</code></td>
|
|
<td>若存在则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy4">::</span><span class="me2">const_pointer</span></span></span> ，否则为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-memory-pointer_traits.html"><span class="kw755">std::<span class="me2">pointer_traits</span></span></a><span class="sy1"><</span>pointer<span class="sy1">></span><span class="sy4">::</span><span class="me2">rebind</span><span class="sy1"><</span><span class="kw4">const</span> value_type<span class="sy1">></span></span></span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>void_pointer</code></td>
|
|
<td>若存在则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy4">::</span><span class="me2">void_pointer</span></span></span> ，否则为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-memory-pointer_traits.html"><span class="kw755">std::<span class="me2">pointer_traits</span></span></a><span class="sy1"><</span>pointer<span class="sy1">></span><span class="sy4">::</span><span class="me2">rebind</span><span class="sy1"><</span><span class="kw4">void</span><span class="sy1">></span></span></span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>const_void_pointer</code></td>
|
|
<td>若存在则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy4">::</span><span class="me2">const_void_pointer</span></span></span> ，否则为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-memory-pointer_traits.html"><span class="kw755">std::<span class="me2">pointer_traits</span></span></a><span class="sy1"><</span>pointer<span class="sy1">></span><span class="sy4">::</span><span class="me2">rebind</span><span class="sy1"><</span><span class="kw4">const</span> <span class="kw4">void</span><span class="sy1">></span></span></span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>difference_type</code></td>
|
|
<td>若存在则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy4">::</span><span class="me2">difference_type</span></span></span> ，否则为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-memory-pointer_traits.html"><span class="kw755">std::<span class="me2">pointer_traits</span></span></a><span class="sy1"><</span>pointer<span class="sy1">></span><span class="sy4">::</span><span class="me2">difference_type</span></span></span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>size_type</code></td>
|
|
<td>若存在则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy4">::</span><span class="me2">size_type</span></span></span> ，否则为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-types-make_unsigned.html"><span class="kw618">std::<span class="me2">make_unsigned</span></span></a><span class="sy1"><</span>difference_type<span class="sy1">></span><span class="sy4">::</span><span class="me2">type</span></span></span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>propagate_on_container_copy_assignment</code></td>
|
|
<td>若存在则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy4">::</span><span class="me2">propagate_on_container_copy_assignment</span></span></span> ，否则为 <span class="t-lc"><a href="cpp-types-integral_constant.html">std::false_type</a></span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>propagate_on_container_move_assignment</code></td>
|
|
<td>若存在则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy4">::</span><span class="me2">propagate_on_container_move_assignment</span></span></span> ，否则为 <span class="t-lc"><a href="cpp-types-integral_constant.html">std::false_type</a></span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>propagate_on_container_swap</code></td>
|
|
<td>若存在则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy4">::</span><span class="me2">propagate_on_container_swap</span></span></span> ，否则为 <span class="t-lc"><a href="cpp-types-integral_constant.html">std::false_type</a></span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>is_always_equal</code><span class="t-mark-rev t-since-cxx17">(C++17 起)</span></td>
|
|
<td>若存在则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy4">::</span><span class="me2">is_always_equal</span></span></span> ，否则为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-types-is_empty.html"><span class="kw508">std::<span class="me2">is_empty</span></span></a><span class="sy1"><</span>Alloc<span class="sy1">></span><span class="sy4">::</span><span class="me2">type</span></span></span></td>
|
|
</tr>
|
|
</table>
|
|
<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E5.88.AB.E5.90.8D.E6.A8.A1.E7.89.88">成员别名模版</span></h3>
|
|
<table class="t-dsc-begin">
|
|
<tr class="t-dsc-hitem">
|
|
<td>类型</td>
|
|
<td>定义</td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>rebind_alloc<T></code></td>
|
|
<td>若存在则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy4">::</span><span class="me2">rebind</span><span class="sy1"><</span>T<span class="sy1">></span><span class="sy4">::</span><span class="me2">other</span></span></span> ，否则若 <span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy1"><</span>T, Args<span class="sy1">></span></span></span> 则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">Alloc<span class="sy1"><</span>U, Args<span class="sy1">></span></span></span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td><code>rebind_traits<T></code></td>
|
|
<td><span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">allocator_traits</span><span class="sy1"><</span>rebind_alloc<span class="sy1"><</span>T<span class="sy1">>></span></span></span></td>
|
|
</tr>
|
|
</table>
|
|
<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E5.87.BD.E6.95.B0">成员函数</span></h3>
|
|
<table class="t-dsc-begin">
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-memory-allocator_traits-allocate.html"><span class="t-lines"><span>allocate</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>用分配器分配未初始化的存储<br />
|
|
<span class="t-mark">(公开静态成员函数)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-memory-allocator_traits-deallocate.html"><span class="t-lines"><span>deallocate</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>用分配器解分配存储<br />
|
|
<span class="t-mark">(公开静态成员函数)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-memory-allocator_traits-construct.html"><span class="t-lines"><span>construct</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>在分配的存储构造对象<br />
|
|
<span class="t-mark">(函数模板)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-memory-allocator_traits-destroy.html"><span class="t-lines"><span>destroy</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>析构存储于已分配存储的对象<br />
|
|
<span class="t-mark">(函数模板)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-memory-allocator_traits-max_size.html"><span class="t-lines"><span>max_size</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>返回分配器所支持的最大对象大小<br />
|
|
<span class="t-mark">(公开静态成员函数)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-memory-allocator_traits-select_on_container_copy_construction.html"><span class="t-lines"><span>select_on_container_copy_construction</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>获得复制标准容器后使用的分配器<br />
|
|
<span class="t-mark">(公开静态成员函数)</span></td>
|
|
</tr>
|
|
</table>
|
|
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
|
|
<table class="t-dsc-begin">
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-memory-allocator.html"><span class="t-lines"><span>allocator</span></span></a></div>
|
|
</div>
|
|
</td>
|
|
<td>默认的分配器<br />
|
|
<span class="t-mark">(类模板)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-memory-scoped_allocator_adaptor.html"><span class="t-lines"><span>scoped_allocator_adaptor</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>为多级容器实现的多级分配器<br />
|
|
<span class="t-mark">(类模板)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-memory-pointer_traits.html"><span class="t-lines"><span>pointer_traits</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>提供关于指针式类型的信息<br />
|
|
<span class="t-mark">(类模板)</span></td>
|
|
</tr>
|
|
</table>
|
|
</div>
|
|
<div class="visualClear"></div>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</body>
|
|
</html>
|