279 lines
27 KiB
HTML
279 lines
27 KiB
HTML
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<title>std::make_unique, std::make_unique_for_overwrite</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_memory_unique_ptr_make_unique 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>make_unique, <span style="font-size:0.7em; line-height:130%">std::</span>make_unique_for_overwrite</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-unique_ptr.html">unique ptr</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-memory.html"><memory></a></code></div>
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</td>
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<td></td>
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<td></td>
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<tr class="t-dcl t-since-cxx14">
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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="kw1">class</span>... <span class="me1">Args</span> <span class="sy1">></span><br />
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unique_ptr<span class="sy1"><</span>T<span class="sy1">></span> make_unique<span class="br0">(</span> Args<span class="sy3">&&</span>... <span class="me1">args</span> <span class="br0">)</span><span class="sy4">;</span></span></div>
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</td>
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<td>(1)</td>
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<td><span class="t-mark-rev t-since-cxx14">(C++14 起)</span><br />
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<span class="t-mark">(仅对非数组类型)</span></td>
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</tr>
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<tr class="t-dcl t-since-cxx14">
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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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unique_ptr<span class="sy1"><</span>T<span class="sy1">></span> make_unique<span class="br0">(</span> <a href="cpp-types-size_t.html"><span class="kw100">std::<span class="me2">size_t</span></span></a> size <span class="br0">)</span><span class="sy4">;</span></span></div>
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</td>
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<td>(2)</td>
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<td><span class="t-mark-rev t-since-cxx14">(C++14 起)</span><br />
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<span class="t-mark">(仅对未知边界数组)</span></td>
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</tr>
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<tr class="t-dcl t-since-cxx14">
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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="kw1">class</span>... <span class="me1">Args</span> <span class="sy1">></span><br />
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<span class="coMULTI">/* unspecified */</span> make_unique<span class="br0">(</span> Args<span class="sy3">&&</span>... <span class="me1">args</span> <span class="br0">)</span> <span class="sy1">=</span> delete<span class="sy4">;</span></span></div>
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</td>
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<td>(3)</td>
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<td><span class="t-mark-rev t-since-cxx14">(C++14 起)</span><br />
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<span class="t-mark">(仅对已知边界数组)</span></td>
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</tr>
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<tr class="t-dcl t-since-cxx20">
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<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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unique_ptr<span class="sy1"><</span>T<span class="sy1">></span> make_unique_for_overwrite<span class="br0">(</span> <span class="br0">)</span><span class="sy4">;</span></span></div>
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</td>
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<td>(4)</td>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span><br />
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<span class="t-mark">(仅对非数组类型)</span></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">template</span><span class="sy1"><</span> <span class="kw1">class</span> T <span class="sy1">></span><br />
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unique_ptr<span class="sy1"><</span>T<span class="sy1">></span> make_unique_for_overwrite<span class="br0">(</span> <a href="cpp-types-size_t.html"><span class="kw100">std::<span class="me2">size_t</span></span></a> size <span class="br0">)</span><span class="sy4">;</span></span></div>
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</td>
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<td>(5)</td>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span><br />
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<span class="t-mark">(仅对未知边界数组)</span></td>
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</tr>
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<tr class="t-dcl t-since-cxx20">
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<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="kw1">class</span>... <span class="me1">Args</span> <span class="sy1">></span><br />
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<span class="coMULTI">/* unspecified */</span> make_unique_for_overwrite<span class="br0">(</span> Args<span class="sy3">&&</span>... <span class="me1">args</span> <span class="br0">)</span> <span class="sy1">=</span> delete<span class="sy4">;</span></span></div>
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</td>
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<td>(6)</td>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 起)</span><br />
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<span class="t-mark">(仅对已知边界数组)</span></td>
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</tr>
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<tr class="t-dcl-sep">
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<td></td>
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<td></td>
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<td></td>
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<p>构造 <code>T</code> 类型对象并将其包装进 <span class="t-lc"><a href="cpp-memory-unique_ptr.html">std::unique_ptr</a></span> 。</p>
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<div class="t-li1"><span class="t-li">1)</span> 构造非数组类型 <code>T</code> 对象。传递参数 <code>args</code> 给 <code>T</code> 的构造函数。此重载仅若 <code>T</code> 不是数组类型才参与重载决议。函数等价于：
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="cpp source-cpp">
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<pre class="de1">unique_ptr<span class="sy1"><</span>T<span class="sy1">></span><span class="br0">(</span>new T<span class="br0">(</span><a href="cpp-utility-forward.html"><span class="kw1116">std::<span class="me2">forward</span></span></a><span class="sy1"><</span>Args<span class="sy1">></span><span class="br0">(</span>args<span class="br0">)</span>...<span class="br0">)</span><span class="br0">)</span></pre></div>
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</div>
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</div>
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<div class="t-li1"><span class="t-li">2)</span> 构造拥有动态大小的数组。<a href="cpp-language-value_initialization.html">值初始化</a>数组元素。此重载仅若 <code>T</code> 是未知边界数组才参与重载决议。函数等价于：
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="cpp source-cpp">
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<pre class="de1">unique_ptr<span class="sy1"><</span>T<span class="sy1">></span><span class="br0">(</span>new <a href="cpp-types-remove_extent.html"><span class="kw621">std::<span class="me2">remove_extent_t</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="br0">[</span>size<span class="br0">]</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span></pre></div>
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</div>
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<div class="t-li1"><span class="t-li">3,6)</span> 不允许构造已知边界的数组。</div>
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<div class="t-li1"><span class="t-li">4)</span> 同 <span class="t-v">(1)</span> ，除了<a href="cpp-language-default_initialization.html">默认初始化</a>对象。此重载仅若 <code>T</code> 不是数组类型才参与重载决议。函数等价于：
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="cpp source-cpp">
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<pre class="de1">unique_ptr<span class="sy1"><</span>T<span class="sy1">></span><span class="br0">(</span>new T<span class="br0">)</span></pre></div>
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</div>
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</div>
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<div class="t-li1"><span class="t-li">5)</span> 同 <span class="t-v">(2)</span> ，除了默认初始化数组。此重载仅若 <code>T</code> 是未知边界数组才参与重载决议。函数等价于：
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="cpp source-cpp">
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<pre class="de1">unique_ptr<span class="sy1"><</span>T<span class="sy1">></span><span class="br0">(</span>new <a href="cpp-types-remove_extent.html"><span class="kw621">std::<span class="me2">remove_extent_t</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="br0">[</span>size<span class="br0">]</span><span class="br0">)</span></pre></div>
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</div>
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</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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<table class="t-par-begin">
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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>将要构造的 <code>T</code> 实例所用的参数列表。</td>
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</tr>
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<tr class="t-par">
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<td>size</td>
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<td>-</td>
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<td>要构造的数组大小</td>
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</tr>
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</table>
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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>类型 <code>T</code> 实例的 <span class="t-lc"><a href="cpp-memory-unique_ptr.html">std::unique_ptr</a></span> 。</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 <span class="t-lc"><a href="cpp-memory-new-bad_alloc.html">std::bad_alloc</a></span> 或任何 <code>T</code> 的构造函数所抛的异常。若抛出异常，则此函数无效果。</p>
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<h3><span class="mw-headline" id=".E5.8F.AF.E8.83.BD.E7.9A.84.E5.AE.9E.E7.8E.B0">可能的实现</span></h3>
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<table class="eq-fun-cpp-table">
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<tr>
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<th>版本一</th>
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</tr>
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<tr>
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<td>
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="cpp source-cpp">
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<pre class="de1"><span class="co1">// C++14 make_unique</span>
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<span class="kw1">namespace</span> detail <span class="br0">{</span>
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<span class="kw1">template</span><span class="sy1"><</span><span class="kw1">class</span><span class="sy1">></span>
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<span class="kw4">constexpr</span> <span class="kw4">bool</span> is_unbounded_array_v <span class="sy1">=</span> <span class="kw2">false</span><span class="sy4">;</span>
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<span class="kw1">template</span><span class="sy1"><</span><span class="kw1">class</span> T<span class="sy1">></span>
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<span class="kw4">constexpr</span> <span class="kw4">bool</span> is_unbounded_array_v<span class="sy1"><</span>T<span class="br0">[</span><span class="br0">]</span><span class="sy1">></span> <span class="sy1">=</span> <span class="kw2">true</span><span class="sy4">;</span>
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<span class="kw1">template</span><span class="sy1"><</span><span class="kw1">class</span><span class="sy1">></span>
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<span class="kw4">constexpr</span> <span class="kw4">bool</span> is_bounded_array_v <span class="sy1">=</span> <span class="kw2">false</span><span class="sy4">;</span>
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<span class="kw1">template</span><span class="sy1"><</span><span class="kw1">class</span> T, <a href="cpp-types-size_t.html"><span class="kw100">std::<span class="me2">size_t</span></span></a> N<span class="sy1">></span>
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<span class="kw4">constexpr</span> <span class="kw4">bool</span> is_bounded_array_v<span class="sy1"><</span>T<span class="br0">[</span>N<span class="br0">]</span><span class="sy1">></span> <span class="sy1">=</span> <span class="kw2">true</span><span class="sy4">;</span>
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<span class="br0">}</span> <span class="co1">// namespace detail</span>
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<span class="kw1">template</span><span class="sy1"><</span><span class="kw1">class</span> T, <span class="kw1">class</span>... <span class="me1">Args</span><span class="sy1">></span>
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<a href="cpp-types-enable_if.html"><span class="kw631">std::<span class="me2">enable_if_t</span></span></a><span class="sy1"><</span><span class="sy3">!</span><a href="cpp-types-is_array.html"><span class="kw460">std::<span class="me2">is_array</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="sy4">::</span><span class="me2">value</span>, <a href="cpp-memory-unique_ptr.html"><span class="kw733">std::<span class="me2">unique_ptr</span></span></a><span class="sy1"><</span>T<span class="sy1">>></span>
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make_unique<span class="br0">(</span>Args<span class="sy3">&&</span>... <span class="me1">args</span><span class="br0">)</span>
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<span class="br0">{</span>
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<span class="kw1">return</span> <a href="cpp-memory-unique_ptr.html"><span class="kw733">std::<span class="me2">unique_ptr</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="br0">(</span>new T<span class="br0">(</span><a href="cpp-utility-forward.html"><span class="kw1116">std::<span class="me2">forward</span></span></a><span class="sy1"><</span>Args<span class="sy1">></span><span class="br0">(</span>args<span class="br0">)</span>...<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="kw1">template</span><span class="sy1"><</span><span class="kw1">class</span> T<span class="sy1">></span>
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<a href="cpp-types-enable_if.html"><span class="kw631">std::<span class="me2">enable_if_t</span></span></a><span class="sy1"><</span>detail<span class="sy4">::</span><span class="me2">is_unbounded_array_v</span><span class="sy1"><</span>T<span class="sy1">></span>, <a href="cpp-memory-unique_ptr.html"><span class="kw733">std::<span class="me2">unique_ptr</span></span></a><span class="sy1"><</span>T<span class="sy1">>></span>
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make_unique<span class="br0">(</span><a href="cpp-types-size_t.html"><span class="kw100">std::<span class="me2">size_t</span></span></a> n<span class="br0">)</span>
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<span class="br0">{</span>
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<span class="kw1">return</span> <a href="cpp-memory-unique_ptr.html"><span class="kw733">std::<span class="me2">unique_ptr</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="br0">(</span>new <a href="cpp-types-remove_extent.html"><span class="kw621">std::<span class="me2">remove_extent_t</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="br0">[</span>n<span class="br0">]</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="kw1">template</span><span class="sy1"><</span><span class="kw1">class</span> T, <span class="kw1">class</span>... <span class="me1">Args</span><span class="sy1">></span>
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<a href="cpp-types-enable_if.html"><span class="kw631">std::<span class="me2">enable_if_t</span></span></a><span class="sy1"><</span>detail<span class="sy4">::</span><span class="me2">is_bounded_array_v</span><span class="sy1"><</span>T<span class="sy1">>></span> make_unique<span class="br0">(</span>Args<span class="sy3">&&</span>...<span class="br0">)</span> <span class="sy1">=</span> delete<span class="sy4">;</span></pre></div>
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</div>
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</td>
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</tr>
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<tr>
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<th>版本二</th>
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</tr>
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<tr>
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<td>
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="cpp source-cpp">
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<pre class="de1"><span class="co1">// C++20 make_unique_for_overwrite</span>
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<span class="kw1">template</span><span class="sy1"><</span><span class="kw1">class</span> T<span class="sy1">></span>
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requires <span class="sy3">!</span><a href="cpp-types-is_array.html"><span class="kw461">std::<span class="me2">is_array_v</span></span></a><span class="sy1"><</span>T<span class="sy1">></span>
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<a href="cpp-memory-unique_ptr.html"><span class="kw733">std::<span class="me2">unique_ptr</span></span></a><span class="sy1"><</span>T<span class="sy1">></span> make_unique_for_overwrite<span class="br0">(</span><span class="br0">)</span>
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<span class="br0">{</span>
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<span class="kw1">return</span> <a href="cpp-memory-unique_ptr.html"><span class="kw733">std::<span class="me2">unique_ptr</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="br0">(</span>new T<span class="br0">)</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="kw1">template</span><span class="sy1"><</span><span class="kw1">class</span> T<span class="sy1">></span>
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requires std<span class="sy4">::</span><span class="me2">is_unbounded_array_v</span><span class="sy1"><</span>T<span class="sy1">></span>
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<a href="cpp-memory-unique_ptr.html"><span class="kw733">std::<span class="me2">unique_ptr</span></span></a><span class="sy1"><</span>T<span class="sy1">></span> make_unique_for_overwrite<span class="br0">(</span><a href="cpp-types-size_t.html"><span class="kw100">std::<span class="me2">size_t</span></span></a> n<span class="br0">)</span>
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<span class="br0">{</span>
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<span class="kw1">return</span> <a href="cpp-memory-unique_ptr.html"><span class="kw733">std::<span class="me2">unique_ptr</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="br0">(</span>new <a href="cpp-types-remove_extent.html"><span class="kw621">std::<span class="me2">remove_extent_t</span></span></a><span class="sy1"><</span>T<span class="sy1">></span><span class="br0">[</span>n<span class="br0">]</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="kw1">template</span><span class="sy1"><</span><span class="kw1">class</span> T, <span class="kw1">class</span>... <span class="me1">Args</span><span class="sy1">></span>
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requires std<span class="sy4">::</span><span class="me2">is_bounded_array_v</span><span class="sy1"><</span>T<span class="sy1">></span>
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<span class="kw4">void</span> make_unique_for_overwrite<span class="br0">(</span>Args<span class="sy3">&&</span>...<span class="br0">)</span> <span class="sy1">=</span> delete<span class="sy4">;</span></pre></div>
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</div>
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</td>
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</table>
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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>不同于 <span class="t-lc"><a href="cpp-memory-shared_ptr-make_shared.html">std::make_shared</a></span> （它拥有 <span class="t-lc"><a href="cpp-memory-shared_ptr-allocate_shared.html">std::allocate_shared</a></span> ）， <code>std::make_unique</code> 没有具分配器的对应物。 <a rel="nofollow" class="external text" href="https://wg21.link/P0211">P0211</a> 中提案的 <code>allocate_unique</code> 会要求为其返回的 <code>unique_ptr<T,D></code> 创作删除器类型 <code>D</code> ，返回类型可能含有分配器对象，并在其 <code>operator()</code> 调用 <code>destroy</code> 和 <code>deallocate</code> 。</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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<div class="t-example">
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<div class="t-example-live-link"></div>
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="cpp source-cpp">
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<pre class="de1"><span class="co2">#include <iostream></span>
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<span class="co2">#include <memory></span>
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<span class="kw1">struct</span> Vec3
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<span class="br0">{</span>
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<span class="kw4">int</span> x, y, z<span class="sy4">;</span>
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<span class="co1">// C++20 起不再需要以下构造函数</span>
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Vec3<span class="br0">(</span><span class="kw4">int</span> x <span class="sy1">=</span> <span class="nu0">0</span>, <span class="kw4">int</span> y <span class="sy1">=</span> <span class="nu0">0</span>, <span class="kw4">int</span> z <span class="sy1">=</span> <span class="nu0">0</span><span class="br0">)</span> <span class="kw1">noexcept</span> <span class="sy4">:</span> x<span class="br0">(</span>x<span class="br0">)</span>, y<span class="br0">(</span>y<span class="br0">)</span>, z<span class="br0">(</span>z<span class="br0">)</span> <span class="br0">{</span> <span class="br0">}</span>
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<span class="kw1">friend</span> <a href="cpp-io-basic_ostream.html"><span class="kw1728">std::<span class="me2">ostream</span></span></a><span class="sy3">&</span> operator<span class="sy1"><<</span><span class="br0">(</span><a href="cpp-io-basic_ostream.html"><span class="kw1728">std::<span class="me2">ostream</span></span></a><span class="sy3">&</span> os, <span class="kw4">const</span> Vec3<span class="sy3">&</span> v<span class="br0">)</span>
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<span class="br0">{</span>
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<span class="kw1">return</span> os <span class="sy1"><<</span> <span class="st0">'{'</span> <span class="sy1"><<</span> <span class="st0">"x:"</span> <span class="sy1"><<</span> v.<span class="me1">x</span> <span class="sy1"><<</span> <span class="st0">" y:"</span> <span class="sy1"><<</span> v.<span class="me1">y</span> <span class="sy1"><<</span> <span class="st0">" z:"</span> <span class="sy1"><<</span> v.<span class="me1">z</span> <span class="sy1"><<</span> <span class="st0">'}'</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="br0">}</span><span class="sy4">;</span>
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<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
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<span class="br0">{</span>
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<span class="co1">// 使用默认构造函数。</span>
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<a href="cpp-memory-unique_ptr.html"><span class="kw733">std::<span class="me2">unique_ptr</span></span></a><span class="sy1"><</span>Vec3<span class="sy1">></span> v1 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">make_unique</span><span class="sy1"><</span>Vec3<span class="sy1">></span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="co1">// 使用匹配这些参数的构造函数</span>
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<a href="cpp-memory-unique_ptr.html"><span class="kw733">std::<span class="me2">unique_ptr</span></span></a><span class="sy1"><</span>Vec3<span class="sy1">></span> v2 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">make_unique</span><span class="sy1"><</span>Vec3<span class="sy1">></span><span class="br0">(</span><span class="nu0">0</span>, <span class="nu0">1</span>, <span class="nu0">2</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="co1">// 创建指向 5 个元素数组的 unique_ptr </span>
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<a href="cpp-memory-unique_ptr.html"><span class="kw733">std::<span class="me2">unique_ptr</span></span></a><span class="sy1"><</span>Vec3<span class="br0">[</span><span class="br0">]</span><span class="sy1">></span> v3 <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">make_unique</span><span class="sy1"><</span>Vec3<span class="br0">[</span><span class="br0">]</span><span class="sy1">></span><span class="br0">(</span><span class="nu0">5</span><span class="br0">)</span><span class="sy4">;</span>
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<a href="cpp-io-cout.html"><span class="kw1757">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"make_unique<Vec3>(): "</span> <span class="sy1"><<</span> <span class="sy2">*</span>v1 <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span>
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<span class="sy1"><<</span> <span class="st0">"make_unique<Vec3>(0,1,2): "</span> <span class="sy1"><<</span> <span class="sy2">*</span>v2 <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span>
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<span class="sy1"><<</span> <span class="st0">"make_unique<Vec3[]>(5): "</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
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<span class="kw1">for</span> <span class="br0">(</span><span class="kw4">int</span> i <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span> i <span class="sy1"><</span> <span class="nu0">5</span><span class="sy4">;</span> i<span class="sy2">++</span><span class="br0">)</span> <span class="br0">{</span>
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<a href="cpp-io-cout.html"><span class="kw1757">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">" "</span> <span class="sy1"><<</span> v3<span class="br0">[</span>i<span class="br0">]</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="br0">}</span></pre></div>
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</div>
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<p>输出：</p>
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="text source-text">
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<pre class="de1">make_unique<Vec3>(): {x:0 y:0 z:0}
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make_unique<Vec3>(0,1,2): {x:0 y:1 z:2}
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make_unique<Vec3[]>(5):
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{x:0 y:0 z:0}
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{x:0 y:0 z:0}
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{x:0 y:0 z:0}
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{x:0 y:0 z:0}
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{x:0 y:0 z:0}</pre></div>
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</div>
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</div>
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<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
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<table class="t-dsc-begin">
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<tr class="t-dsc">
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<td>
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<div class="t-dsc-member-div t-dsc-member-nobold-div">
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<div><a href="cpp-memory-unique_ptr-unique_ptr.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>构造新的<code>unique_ptr</code><br />
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<span class="t-mark">(公开成员函数)</span></td>
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</tr>
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<tr class="t-dsc">
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<td>
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<div class="t-dsc-member-div">
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<div><a href="cpp-memory-shared_ptr-make_shared.html"><span class="t-lines"><span>make_shared</span><span>make_shared_for_overwrite</span></span></a></div>
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<div><span class="t-lines"><span></span><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>创建管理一个新对象的共享指针<br />
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<span class="t-mark">(函数模板)</span></td>
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</tr>
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</table>
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</div>
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<div class="visualClear"></div>
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</div>
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</div>
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</div>
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</body>
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</html>
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