151 lines
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151 lines
9.0 KiB
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<title>std::atomic_load, std::atomic_load_explicit</title>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::</span>atomic_load, <span style="font-size:0.7em; line-height:130%">std::</span>atomic_load_explicit</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 rowspan="142">(1)</td>
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<td rowspan="142"><span class="t-mark-rev t-since-cxx11">(C++11 起)</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 />
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T atomic_load<span class="br0">(</span> <span class="kw4">const</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 <span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span></span></div>
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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 />
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T atomic_load<span class="br0">(</span> <span class="kw4">const</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 <span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span></span></div>
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<td rowspan="142">(2)</td>
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<td rowspan="142"><span class="t-mark-rev t-since-cxx11">(C++11 起)</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>T atomic_load_explicit<span class="br0">(</span> <span class="kw4">const</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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<a href="cpp-atomic-memory_order.html"><span class="kw2090">std::<span class="me2">memory_order</span></span></a> order <span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span></div>
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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>T atomic_load_explicit<span class="br0">(</span> <span class="kw4">const</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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<a href="cpp-atomic-memory_order.html"><span class="kw2090">std::<span class="me2">memory_order</span></span></a> order <span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span></div>
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<div class="t-li1"><span class="t-li">1)</span> 如同用 <span class="t-c"><span class="mw-geshi cpp source-cpp">obj<span class="sy2">-</span><span class="sy1">></span>load<span class="br0">(</span><span class="br0">)</span></span></span> 原子地获得 <code>obj</code> 所指向的值。</div>
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<div class="t-li1"><span class="t-li">2)</span> 如同用 <span class="t-c"><span class="mw-geshi cpp source-cpp">obj<span class="sy2">-</span><span class="sy1">></span>load<span class="br0">(</span>order<span class="br0">)</span></span></span> 原子地获得 <code>obj</code> 所指向的值。</div>
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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>指向要加载的原子对象的指针</td>
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<td>order</td>
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<td>-</td>
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<td>此操作所用的内存同步顺序：只容许 <span class="t-lc"><a href="cpp-atomic-memory_order.html">std::memory_order_relaxed</a></span> 、 <span class="t-lc"><a href="cpp-atomic-memory_order.html">std::memory_order_consume</a></span> 、 <span class="t-lc"><a href="cpp-atomic-memory_order.html">std::memory_order_acquire</a></span> 和 <span class="t-lc"><a href="cpp-atomic-memory_order.html">std::memory_order_seq_cst</a></span> 。</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><code>obj</code> 所指向的原子对象所保有的值。</p>
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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-atomic-atomic-load.html"><span class="t-lines"><span>load</span></span></a></div>
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<td>原子地获得原子对象的值<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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<div><a href="cpp-atomic-atomic_store.html"><span class="t-lines"><span>atomic_store</span><span>atomic_store_explicit</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><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div>
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<td>原子地以非原子实参替换原子对象的值<br />
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<span class="t-mark">(函数模板)</span></td>
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<div><a href="cpp-atomic-memory_order.html"><span class="t-lines"><span>memory_order</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></span></div>
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<td>为给定的原子操作定义内存顺序约束<br />
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<span class="t-mark">(枚举)</span></td>
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<div><a href="cpp-memory-shared_ptr-atomic.html"><span class="t-lines"><span>std::atomic_load<span class="t-dsc-small">(std::shared_ptr)</span></span> <span>std::atomic_load_explicit<span class="t-dsc-small">(std::shared_ptr)</span></span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-deprecated-cxx20">(C++20 中弃用)</span></span></span></div>
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<td>为 std::shared_ptr 特化原子操作<br />
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<span class="t-mark">(函数模板)</span></td>
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