125 lines
8.4 KiB
HTML
125 lines
8.4 KiB
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::ctime</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_chrono_c_ctime skin-cppreference2 action-view cpp-navbar">
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<div id="cpp-content-base">
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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::</span>ctime</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>‎ | <a href="cpp-chrono-c.html">c</a></span></div>
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<div>定义于头文件 <code><a href="cpp-header-ctime.html"><ctime></a></code></div>
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<td></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">char</span><span class="sy2">*</span> ctime<span class="br0">(</span> <span class="kw4">const</span> <a href="cpp-chrono-c-time_t.html"><span class="kw1023">std::<span class="me2">time_t</span></span></a><span class="sy2">*</span> time <span class="br0">)</span><span class="sy4">;</span></span></div>
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<p>转换给定的从纪元起时间为日历时间,再转换为文本表示,如同通过调用 <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-chrono-c-asctime.html"><span class="kw1015">std::<span class="me2">asctime</span></span></a><span class="br0">(</span><a href="cpp-chrono-c-localtime.html"><span class="kw1019">std::<span class="me2">localtime</span></span></a><span class="br0">(</span>time<span class="br0">)</span><span class="br0">)</span></span></span> 。 产生的字符串拥有如下格式:</p>
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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">Www Mmm dd hh<span class="sy4">:</span>mm<span class="sy4">:</span>ss yyyy\n</pre></div>
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</div>
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<ul>
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<li><code>Www</code> - 星期( <code>Mon</code> 、 <code>Tue</code> 、 <code>Wed</code> 、 <code>Thu</code> 、 <code>Fri</code> 、 <code>Sat</code> 、 <code>Sun</code> 之一)。</li>
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<li><code>Mmm</code> - 月份( <code>Jan</code> 、 <code>Feb</code> 、 <code>Mar</code> 、 <code>Apr</code> 、 <code>May</code> 、 <code>Jun</code> 、 <code>Jul</code> 、 <code>Aug</code> 、 <code>Sep</code> 、 <code>Oct</code> 、 <code>Nov</code> 、 <code>Dec</code> 之一)。</li>
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<li><code>dd</code> - 月之日</li>
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<li><code>hh</code> - 时</li>
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<li><code>mm</code> - 分</li>
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<li><code>ss</code> - 秒</li>
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<li><code>yyyy</code> - 年</li>
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</ul>
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<p>函数不支持本地化。</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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<td>time</td>
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<td>-</td>
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<td>指向指定要打印时间的 <span class="t-lc"><a href="cpp-chrono-c-time_t.html">std::time_t</a></span> 对象</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>返回指向静态空终止字符串的指针,字符串保有上述的日期和时间的文本表示。字符串可以在 <code>std::asctime</code> 和 <span class="t-lc"><strong class="selflink">std::ctime</strong></span> 间共享,并且可以被每次对这些函数的调用重写。</p>
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<h3><span class="mw-headline" id=".E6.B3.A8.E6.84.8F">注意</span></h3>
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<p><code>ctime</code> 返回指向静态数据的指针,而且非线程安全。另外它修改可能会为 <span class="t-lc"><a href="cpp-chrono-c-gmtime.html">std::gmtime</a></span> 及 <span class="t-lc"><a href="cpp-chrono-c-localtime.html">std::localtime</a></span> 所共享的静态 <span class="t-lc"><a href="cpp-chrono-c-tm.html">std::tm</a></span> 对象。 POSIX 标记此函数标为过时,并推荐用 <span class="t-lc"><a href="cpp-chrono-c-strftime.html">std::strftime</a></span> 替代。</p>
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<p>对于导致字符串长于 25 字符(例如, 10000 年)的 <code>time_t</code> 的值, <code>ctime</code> 的行为可能未定义。</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 <ctime></span>
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<span class="co2">#include <iostream></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-chrono-c-time_t.html"><span class="kw1023">std::<span class="me2">time_t</span></span></a> result <span class="sy1">=</span> <a href="cpp-chrono-c-time.html"><span class="kw1011">std::<span class="me2">time</span></span></a><span class="br0">(</span>nullptr<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> std<span class="sy4">::</span><span class="me2">ctime</span><span class="br0">(</span><span class="sy3">&</span>result<span class="br0">)</span><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">Tue Dec 27 17:21:29 2011</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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<td>
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<div class="t-dsc-member-div">
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<div><a href="cpp-chrono-c-asctime.html"><span class="t-lines"><span>asctime</span></span></a></div>
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</div>
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</td>
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<td>转换 <code>tm</code> 对象为文本表示<br />
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<span class="t-mark">(函数)</span></td>
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</tr>
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<div class="t-dsc-member-div">
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<div><a href="cpp-chrono-c-strftime.html"><span class="t-lines"><span>strftime</span></span></a></div>
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</div>
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</td>
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<td>转换 <code>tm</code> 对象到自定义的文本表示<br />
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<span class="t-mark">(函数)</span></td>
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<div class="t-dsc-member-div">
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<div><a href="cpp-io-manip-put_time.html"><span class="t-lines"><span>put_time</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div>
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</div>
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</td>
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<td>按照指定格式格式化并输出日期/时间值<br />
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<span class="t-mark">(函数模板)</span></td>
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<div class="visualClear"></div>
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