104 lines
6.5 KiB
HTML
104 lines
6.5 KiB
HTML
<!DOCTYPE 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::unique_ptr<T,Deleter>::release</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_memory_unique_ptr_release skin-cppreference2 action-view cpp-navbar">
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<div id="cpp-content-base">
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<div id="content"><a id="top"></a>
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::unique_ptr<T,Deleter>::</span>release</h1>
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<div id="bodyContent">
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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><span class="mw-geshi cpp source-cpp">pointer release<span class="br0">(</span><span class="br0">)</span> <span class="kw1">noexcept</span><span class="sy4">;</span></span></div>
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<td class="t-dcl-nopad"></td>
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<td><span class="t-mark-rev t-since-cxx11">(C++11 起)</span></td>
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<p>若存在，则释放被管理对象的所有权。调用后 <span class="t-lc"><a href="cpp-memory-unique_ptr-get.html">get()</a></span> 返回 <span class="t-c"><span class="mw-geshi cpp source-cpp">nullptr</span></span> 。</p>
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<p>调用方负责删除该对象。</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>指向被管理对象的指针，或若无被管理对象则为 <span class="t-c"><span class="mw-geshi cpp source-cpp">nullptr</span></span> ，即调用前 <span class="t-lc"><a href="cpp-memory-unique_ptr-get.html">get()</a></span> 会返回的值。</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 <memory></span>
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<span class="co2">#include <iostream></span>
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<span class="co2">#include <cassert></span>
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<span class="kw1">struct</span> Foo <span class="br0">{</span>
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Foo<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span> <a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"Foo<span class="es1">\n</span>"</span><span class="sy4">;</span> <span class="br0">}</span>
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~Foo<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span> <a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"~Foo<span class="es1">\n</span>"</span><span class="sy4">;</span> <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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<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"Creating new Foo...<span class="es1">\n</span>"</span><span class="sy4">;</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>Foo<span class="sy1">></span> up<span class="br0">(</span>new Foo<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"About to release Foo...<span class="es1">\n</span>"</span><span class="sy4">;</span>
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Foo<span class="sy2">*</span> fp <span class="sy1">=</span> up.<span class="me1">release</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
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<a href="cpp-error-assert.html"><span class="kw774">assert</span></a> <span class="br0">(</span>up.<span class="me1">get</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">==</span> nullptr<span class="br0">)</span><span class="sy4">;</span>
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<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"Foo is no longer owned by unique_ptr...<span class="es1">\n</span>"</span><span class="sy4">;</span>
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delete fp<span class="sy4">;</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">Creating new Foo...
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Foo
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About to release Foo...
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Foo is no longer owned by unique_ptr...
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~Foo</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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<div class="t-dsc-member-div">
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<div><a href="cpp-memory-unique_ptr-get.html"><span class="t-lines"><span>get</span></span></a></div>
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</div>
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</td>
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<td>返回指向被管理对象的指针<br />
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<span class="t-mark">(公开成员函数)</span></td>
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<tr class="t-dsc">
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<div class="t-dsc-member-div">
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<div><a href="cpp-memory-unique_ptr-reset.html"><span class="t-lines"><span>reset</span></span></a></div>
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</div>
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</td>
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<td>替换被管理对象<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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</div>
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<div class="visualClear"></div>
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</body>
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