77 lines
5.7 KiB
HTML
77 lines
5.7 KiB
HTML
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<title>std::out_ptr_t<Smart,Pointer,Args...>::out_ptr_t</title>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::out_ptr_t<Smart,Pointer,Args...>::</span>out_ptr_t</h1>
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-memory.html">memory</a>‎ | <a href="cpp-memory-out_ptr_t.html">out ptr t</a></span></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">explicit</span> out_ptr_t<span class="br0">(</span> Smart <span class="sy3">&</span>sp, Args... <span class="me1">args</span> <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td>(1)</td>
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<td><span class="t-mark-rev t-since-cxx23">(C++23 起)</span></td>
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<div><span class="mw-geshi cpp source-cpp">out_ptr_t<span class="br0">(</span> <span class="kw4">const</span> out_ptr_t<span class="sy3">&</span> <span class="br0">)</span> <span class="sy1">=</span> delete<span class="sy4">;</span></span></div>
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<td>(2)</td>
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<td><span class="t-mark-rev t-since-cxx23">(C++23 起)</span></td>
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<div class="t-li1"><span class="t-li">1)</span> 创建 <code>out_ptr_t</code> 。如同将 <code>sp</code> 绑定到 <span class="t-c"><span class="mw-geshi cpp source-cpp">Smart<span class="sy3">&</span></span></span> 成员一般适配它，如同用 <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-utility-forward.html"><span class="kw1117">std::<span class="me2">forward</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="br0">(</span>t<span class="br0">)</span></span></span> 初始化对应的 <code>Args...</code> 中类型 <code>T</code> 的成员一般捕获 <code>args...</code> 中的实参 <code>t</code> ，然后值初始化存储的 <code>Pointer</code> 。</div>
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<div class="t-li1"><span class="t-li">2)</span> 复制构造函数被显示删除。 <code>out_ptr_t</code> 既不可复制又不可移动。</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>sp</td>
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<td>-</td>
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<td>要适配的对象（常为智能指针）</td>
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<tr class="t-par">
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<td>args...</td>
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<td>-</td>
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<td>要捕获的用于重设的实参</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=".E5.BC.82.E5.B8.B8">异常</span></h3>
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<p>可能抛出实现定义的异常。</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>构造后，任一转换函数的返回值所指向的 <code>Pointer</code> 或 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span><span class="sy2">*</span></span></span> 对象等于 <span class="t-c"><span class="mw-geshi cpp source-cpp">nullptr</span></span> 。</p>
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<p><code>args...</code> 中的每个参数若拥有对象类型则被移动到创建的 <code>out_ptr_t</code> 中，而若拥有引用类型则保持原状转移到创建的 <code>out_ptr_t</code> 中。</p>
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<p>允许 <code>out_ptr_t</code> 抛出异常。例如当 <code>sp</code> 为 <span class="t-lc"><a href="cpp-memory-shared_ptr.html">std::shared_ptr</a></span> 时，新的控制块的分配可以在构造函数而非析构函数内进行。</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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