153 lines
6.8 KiB
HTML
153 lines
6.8 KiB
HTML
<!DOCTYPE html>
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<html lang="zh" dir="ltr" class="client-nojs" xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh">
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<head><meta http-equiv="x-ua-compatible" content="ie=edge">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<title>std::latch</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_thread_latch skin-cppreference2 action-view cpp-navbar">
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<div id="cpp-content-base">
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<div id="content"><a id="top"></a>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::</span>latch</h1>
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<div id="bodyContent">
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-thread.html">thread</a></span></div>
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<div id="mw-content-text" lang="zh" dir="ltr" class="mw-content-ltr" xml:lang="zh">
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<table class="t-dcl-begin">
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<div>定义于头文件 <code><a href="cpp-header-latch.html"><latch></a></code></div>
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<td></td>
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<td></td>
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<tr class="t-dcl t-since-cxx20">
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">class</span> latch<span class="sy4">;</span></span></div>
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<td class="t-dcl-nopad"></td>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></td>
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<p><code>latch</code> 是 <span class="t-lc"><a href="cpp-types-ptrdiff_t.html">std::ptrdiff_t</a></span> 类型的向下计数器，它能用于同步线程。在创建时初始化计数器的值。</p>
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<p>线程可能在 <code>latch</code> 上阻塞直至计数器减少到零。没有可能增加或重置计数器，这使得 <code>latch</code> 为单次使用的屏障。</p>
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<p>同时调用 <code>latch</code> 的成员函数，除了析构函数，不引入数据竞争。</p>
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<p>不同于 <a href="cpp-thread-barrier.html"><tt>std::barrier</tt></a> ，参与线程能减少 <code>std::latch</code> 多于一次。</p>
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<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E5.87.BD.E6.95.B0">成员函数</span></h3>
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<div class="t-dsc-member-div t-dsc-member-nobold-div">
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<div><a href="cpp-thread-latch-latch.html"><span class="t-lines"><span>(构造函数)</span></span></a></div>
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</div>
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</td>
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<td>构造 <code>latch</code><br />
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<span class="t-mark">(公开成员函数)</span></td>
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<div class="t-dsc-member-div t-dsc-member-nobold-div">
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<div><a href="cpp-thread-latch-~latch.html"><span class="t-lines"><span>(析构函数)</span></span></a></div>
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</div>
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</td>
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<td>析构 <code>latch</code><br />
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<span class="t-mark">(公开成员函数)</span></td>
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<tr class="t-dsc">
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<div class="t-dsc-member-div">
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<div><span class="t-lines"><span>operator=</span></span></div>
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<div><span class="t-lines"><span><span class="t-cmark">[被删除]</span></span></span></div>
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<td><code>latch</code> 不可赋值<br />
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<span class="t-mark">(公开成员函数)</span></td>
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<div class="t-dsc-member-div">
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<div><a href="cpp-thread-latch-count_down.html"><span class="t-lines"><span>count_down</span></span></a></div>
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</div>
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</td>
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<td>以不阻塞的方式减少计数器<br />
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<span class="t-mark">(公开成员函数)</span></td>
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<div><a href="cpp-thread-latch-try_wait.html"><span class="t-lines"><span>try_wait</span></span></a></div>
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</td>
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<td>测试内部计数器是否等于零<br />
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<span class="t-mark">(公开成员函数)</span></td>
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<div><a href="cpp-thread-latch-wait.html"><span class="t-lines"><span>wait</span></span></a></div>
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</td>
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<td>阻塞直至计数器抵达零<br />
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<span class="t-mark">(公开成员函数)</span></td>
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<tr class="t-dsc">
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<div class="t-dsc-member-div">
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<div><a href="cpp-thread-latch-arrive_and_wait.html"><span class="t-lines"><span>arrive_and_wait</span></span></a></div>
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</div>
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</td>
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<td>减少计数器并阻塞直至它抵达零<br />
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<span class="t-mark">(公开成员函数)</span></td>
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<h5><span class="mw-headline" id=".E5.B8.B8.E9.87.8F">常量</span></h5>
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<div><a href="cpp-thread-latch-max.html"><span class="t-lines"><span>max</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div>
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</td>
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<td>实现所支持的计数器最大值<br />
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<span class="t-mark">(公开静态成员函数)</span></td>
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</table>
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<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">示例</span></h3>
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<td class="mbox-text" style="">本节未完成<br />
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原因：暂无示例</td>
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<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
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<div class="t-dsc-member-div">
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<div><a href="cpp-thread-barrier.html"><span class="t-lines"><span>barrier</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>可复用的线程屏障<br />
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<span class="t-mark">(类模板)</span></td>
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<div class="visualClear"></div>
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