89 lines
5.9 KiB
HTML
89 lines
5.9 KiB
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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<title>std::shared_mutex::lock_shared</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_thread_shared_mutex_lock_shared skin-cppreference2 action-view cpp-navbar">
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::shared_mutex::</span>lock_shared</h1>
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-thread.html">thread</a>‎ | <a href="cpp-thread-shared_mutex.html">shared mutex</a></span></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span> lock_shared<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx17">(C++17 起)</span></td>
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<p>获得互斥的共享所有权。若另一线程以排他性所有权保有互斥，则到 <code>lock_shared</code> 的调用将阻塞执行，直到能取得共享所有权。</p>
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<p>若已以任何模式（排他性或共享）占有 <code>mutex</code> 的线程调用 <code>lock_shared</code> ，则行为未定义。</p>
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<p>若多于实现定义最大数量的共享所有者已以共享模式锁定互斥，则 <code>lock_shared</code> 阻塞执行，直至共享所有者的数量减少。所有者的最大数量保证至少为 10000 。</p>
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<p>同一互斥上先前的 <span class="t-lc"><a href="cpp-thread-shared_mutex-unlock.html">unlock()</a></span> 操作<i>同步于</i>（定义于 <span class="t-lc"><a href="cpp-atomic-memory_order.html">std::memory_order</a></span> ）此操作。</p>
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<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">参数</span></h3>
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<p>（无）</p>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">返回值</span></h3>
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<p>（无）</p>
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<h3><span class="mw-headline" id=".E5.BC.82.E5.B8.B8">异常</span></h3>
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<p>出现错误时抛出 <span class="t-lc"><a href="cpp-error-system_error.html">std::system_error</a></span> ，包括来自底层系统将阻止 <code>lock</code> 满足规定的错误。在抛出任何异常的情况下，互斥不被锁定。</p>
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<h3><span class="mw-headline" id=".E6.B3.A8.E6.84.8F">注意</span></h3>
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<p>通常不直接调用 <code>lock_shared()</code> ：用 <span class="t-lc"><a href="cpp-thread-shared_lock.html">std::shared_lock</a></span> 管理共享锁定。</p>
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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><a href="cpp-thread-shared_mutex-lock.html"><span class="t-lines"><span>lock</span></span></a></div>
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<td>锁定互斥，若互斥不可用则阻塞<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-shared_mutex-try_lock_shared.html"><span class="t-lines"><span>try_lock_shared</span></span></a></div>
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</td>
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<td>尝试为共享所有权锁定互斥，若互斥不可用则返回<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-shared_mutex-unlock_shared.html"><span class="t-lines"><span>unlock_shared</span></span></a></div>
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</div>
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</td>
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<td>解锁互斥（共享所有权）<br />
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<span class="t-mark">(公开成员函数)</span></td>
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