125 lines
7.5 KiB
HTML
125 lines
7.5 KiB
HTML
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<title>std::atomic_init</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_atomic_atomic_init 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::</span>atomic_init</h1>
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-atomic.html">atomic</a></span></div>
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<div>定义于头文件 <code><a href="cpp-header-atomic.html"><atomic></a></code></div>
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<td></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> T <span class="sy1">></span><br /></span>
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<p><span class="kw4">void</span> atomic_init<span class="br0">(</span> <a href="cpp-atomic-atomic.html"><span class="kw2066">std::<span class="me2">atomic</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="sy2">*</span> obj,<br /></p>
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<span class="kw1">typename</span> <a href="cpp-atomic-atomic.html"><span class="kw2066">std::<span class="me2">atomic</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="sy4">::</span><span class="me2">value_type</span> desired <span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span></div>
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<td><span class="t-mark-rev t-since-cxx11">(C++11 起)</span><br />
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<span class="t-mark">(C++20 中弃用)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> T <span class="sy1">></span><br /></span>
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<p><span class="kw4">void</span> atomic_init<span class="br0">(</span> <span class="kw4">volatile</span> <a href="cpp-atomic-atomic.html"><span class="kw2066">std::<span class="me2">atomic</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="sy2">*</span> obj,<br /></p>
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<span class="kw1">typename</span> <a href="cpp-atomic-atomic.html"><span class="kw2066">std::<span class="me2">atomic</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="sy4">::</span><span class="me2">value_type</span> desired <span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span></div>
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<td><span class="t-mark-rev t-since-cxx11">(C++11 起)</span><br />
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<span class="t-mark">(C++20 中弃用)</span></td>
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<td></td>
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<p>以值 <code>desired</code> 初始化默认构造的原子对象 <code>obj</code> 。函数非原子：来自其他线程的并发访问，即使通过原子操作，也是数据竞争。</p>
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<p>若 <code>obj</code> 不是默认构造的，则行为未定义。</p>
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<p>若在同一 <code>obj</code> 上调用函数二次，则行为未定义。</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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<td>obj</td>
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<td>-</td>
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<td>指向要初始化的原子对象的指针</td>
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</tr>
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<tr class="t-par">
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<td>desired</td>
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<td>-</td>
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<td>用以初始化原子对象的值</td>
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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=".E6.B3.A8.E8.A7.A3">注解</span></h3>
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<p>为与 C 兼容提供此函数。若不要求兼容性，可通过其默认构造函数初始化 <span class="t-lc"><a href="cpp-atomic-atomic.html">std::atomic</a></span> 。</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=".E7.BC.BA.E9.99.B7.E6.8A.A5.E5.91.8A">缺陷报告</span></h3>
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<p>下列更改行为的缺陷报告追溯地应用于以前出版的 C++ 标准。</p>
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<table class="dsctable" style="font-size:0.8em">
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<th>DR</th>
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<th>应用于</th>
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<th>出版时的行为</th>
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<th>正确行为</th>
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<td><a rel="nofollow" class="external text" href="https://wg21.link/P0558R1">P0558R1</a></td>
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<td>C++11</td>
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<td>曾要求准确类型匹配，因为从多个参数推导 <code>T</code></td>
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<td>仅从 <code>atomic</code> 参数推导 <code>T</code></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-atomic-ATOMIC_VAR_INIT.html"><span class="t-lines"><span>ATOMIC_VAR_INIT</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span><span class="t-mark-rev t-deprecated-cxx20">(C++20 中弃用)</span></span></span></div>
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</td>
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<td>静态存储期的原子对象的常量初始化<br />
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<span class="t-mark">(宏函数)</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-atomic-atomic-atomic.html"><span class="t-lines"><span>(构造函数)</span></span></a></div>
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</div>
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<td>构造原子对象<br />
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<span class="t-mark">(<code>std::atomic<T></code> 的公开成员函数)</span></td>
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</table>
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</div>
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<div class="visualClear"></div>
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