131 lines
7.0 KiB
HTML
131 lines
7.0 KiB
HTML
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<title>std::chrono::local_info</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_chrono_local_info 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::chrono::</span>local_info</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-chrono.html">chrono</a></span></div>
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<div>定义于头文件 <code><a href="cpp-header-chrono.html"><chrono></a></code></div>
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<td></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">struct</span> local_info<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-cxx20">(C++20 起)</span></td>
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<p>类 <code>local_info</code> 描述转换 <span class="t-lc">std::chrono::local_time</span> 为 <span class="t-lc">std::chrono::sys_time</span> 的结果。</p>
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<ul>
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<li>若转换结果唯一，则 <span class="t-c"><span class="mw-geshi cpp source-cpp">result <span class="sy1">==</span> local_info<span class="sy4">::</span><span class="me2">unique</span></span></span> ，以正确的 <span class="t-lc">std::chrono::sys_info</span> 填充 <code>first</code> ，并零初始化 <code>second</code> 。</li>
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<li>若 <code>local_time</code> 不存在，则 <span class="t-c"><span class="mw-geshi cpp source-cpp">result <span class="sy1">==</span> local_info<span class="sy4">::</span><span class="me2">nonexistent</span></span></span> ，以恰在 <code>local_time</code> 前结束的 <span class="t-lc">std::chrono::sys_info</span> 填充 <code>first</code> ，并以恰在 <code>local_time</code> 后开始的 <span class="t-lc">std::chrono::sys_info</span> 填充 <code>second</code> 。</li>
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<li>若 <code>local_time</code> 有歧义，则 <span class="t-c"><span class="mw-geshi cpp source-cpp">result <span class="sy1">==</span> local_info<span class="sy4">::</span><span class="me2">ambiguous</span></span></span> ，以恰在 <code>local_time</code> 后结束的 <span class="t-lc">std::chrono::sys_info</span> 填充 <code>first</code> ，并以恰在 <code>local_time</code> 前开始的 <span class="t-lc">std::chrono::sys_info</span> 填充 <code>second</code> 。</li>
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</ul>
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<p>这是低层数据结构；从 <code>local_time</code> 到 <code>sys_time</code> 的典型转换将隐式使用它，而非显式。</p>
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<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E5.B8.B8.E9.87.8F">成员常量</span></h3>
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<td>名称</td>
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<td>值</td>
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<div><span class="t-lines"><span><span class="t-dsc-small">constexpr int</span> unique</span></span></div>
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<div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div>
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</td>
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<td>0<br />
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<span class="t-mark">(公开静态成员常量)</span></td>
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<div><span class="t-lines"><span><span class="t-dsc-small">constexpr int</span> nonexistent</span></span></div>
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<div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div>
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</td>
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<td>1<br />
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<span class="t-mark">(公开静态成员常量)</span></td>
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<div><span class="t-lines"><span><span class="t-dsc-small">constexpr int</span> ambiguous</span></span></div>
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<div><span class="t-lines"><span><span class="t-cmark">[静态]</span></span></span></div>
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</div>
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</td>
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<td>2<br />
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<span class="t-mark">(公开静态成员常量)</span></td>
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</tr>
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<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E5.AF.B9.E8.B1.A1">成员对象</span></h3>
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<td>成员对象</td>
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<td>类型</td>
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<td><code>result</code></td>
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<td><span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">int</span></span></span></td>
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<td><code>first</code>, <code>second</code></td>
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<td><span class="t-lc">std::chrono::sys_info</span></td>
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<h3><span class="mw-headline" id=".E9.9D.9E.E6.88.90.E5.91.98.E5.87.BD.E6.95.B0">非成员函数</span></h3>
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<div><a href="cpp-chrono-local_info-operator_ltlt.html"><span class="t-lines"><span>operator<<</span></span></a></div>
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<div><span class="t-lines"><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>输出 <code>local_info</code> 对象到流中<br />
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<span class="t-mark">(函数模板)</span></td>
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<h3><span class="mw-headline" id=".E8.BE.85.E5.8A.A9.E7.B1.BB">辅助类</span></h3>
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<div><a href="cpp-chrono-local_info-formatter.html"><span class="t-lines"><span>std::formatter<span class="t-dsc-small"><std::chrono::local_info></span></span></span></a></div>
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<div><span class="t-lines"><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><span class="t-lc">std::formatter</span> 的特化，按照提供的格式格式化 <code>local_info</code><br />
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<span class="t-mark">(类模板特化)</span></td>
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