112 lines
6.5 KiB
HTML
112 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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<head><meta http-equiv="x-ua-compatible" content="ie=edge">
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<title>std::unexpected</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_error_unexpected 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::</span>unexpected</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-error.html">error</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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<tbody>
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<tr class="t-dsc-header">
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<td>
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<div>定义于头文件 <code><a href="cpp-header-exception.html"><exception></a></code></div>
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<td></td>
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<td></td>
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<tbody class="t-dcl-rev">
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<tr class="t-dcl t-until-cxx11">
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span> unexpected<span class="br0">(</span><span class="br0">)</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-until-cxx11">(C++11 前)</span></td>
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<tr class="t-dcl t-since-cxx11 t-until-cxx17">
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<div><span class="mw-geshi cpp source-cpp"><span class="br0">[</span><span class="br0">[</span>noreturn<span class="br0">]</span><span class="br0">]</span> <span class="kw4">void</span> unexpected<span class="br0">(</span><span class="br0">)</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><br />
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<span class="t-mark">(弃用)</span><br />
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<span class="t-mark-rev t-until-cxx17">(C++17 中移除)</span></td>
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<p><code>std::unexpected()</code> 为 C++ 运行时在违背<a href="cpp-language-except_spec.html">动态异常规定</a>时调用：从其异常规定禁止此类型异常的函数抛出该类型异常。</p>
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<p>亦可从程序直接调用 <code>std::unexpected()</code> 。</p>
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<p>任一情况下， <code>std::unexpected</code> 调用当前安装的 <span class="t-lc"><a href="cpp-error-unexpected_handler.html">std::unexpected_handler</a></span> 。默认的 <span class="t-lc"><a href="cpp-error-unexpected_handler.html">std::unexpected_handler</a></span> 调用 <span class="t-lc"><a href="cpp-error-terminate.html">std::terminate</a></span> 。</p>
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<table class="t-rev-begin">
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<tr class="t-rev t-until-cxx11">
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<p>若析构函数在栈回溯期间重置 unexpected_handler 且之后的回溯导致调用 <code>unexpected</code> ，则将调用于 throw 表达式结尾安装的处理函数。（注意：重抛出是否应用新的处理函数是有歧义的）</p>
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</td>
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<td><span class="t-mark-rev t-until-cxx11">(C++11 前)</span></td>
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<tr class="t-rev t-since-cxx11">
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<td>
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<p>若析构函数在栈回溯期间重置 unexpected_handler ，则若之后的回溯导致调用 <code>unexpected</code> ，则调用哪个处理函数是未指定的。</p>
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</td>
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<td><span class="t-mark-rev t-since-cxx11">(C++11 起)</span></td>
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</table>
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<p><br /></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>（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>抛出当前安装的 <span class="t-lc"><a href="cpp-error-unexpected_handler.html">std::unexpected_handler</a></span> 所抛的异常</p>
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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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<tr>
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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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<tr>
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<td><a rel="nofollow" class="external text" href="https://cplusplus.github.io/LWG/issue2111">LWG 2111</a></td>
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<td>C++11</td>
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<td>在栈回溯期间调用 <code>set_unexpected</code> 的效果异于 C++98 并破坏一些 ABI</td>
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<td>令它未指定</td>
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</tr>
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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-error-unexpected_handler.html"><span class="t-lines"><span>unexpected_handler</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-until-cxx17">(C++17 中移除)</span></span></span></div>
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</div>
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</td>
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<td><span class="t-lc"><strong class="selflink">std::unexpected</strong></span> 所调用的函数类型<br />
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<span class="t-mark">(typedef)</span></td>
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</table>
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</div>
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