153 lines
9.0 KiB
HTML
153 lines
9.0 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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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<title>time</title>
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<link rel="stylesheet" href="ext.css" />
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<link rel="stylesheet" href="site_modules.css" />
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</head>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-c_chrono_time 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">time</h1>
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<div id="bodyContent">
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<div id="contentSub"><span class="subpages">< <a href="c.html">c</a>‎ | <a href="c-chrono.html">chrono</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><time.h></code></div>
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</td>
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<td></td>
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<td></td>
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</tr>
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<tr class="t-dcl">
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<td class="t-dcl-nopad">
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<div><span class="mw-geshi c source-c"><a href="c-chrono-time_t.html"><span class="kw523">time_t</span></a> time<span class="br0">(</span> <a href="c-chrono-time_t.html"><span class="kw523">time_t</span></a> <span class="sy2">*</span>arg <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td class="t-dcl-nopad"></td>
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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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</tbody>
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<p>返回编码成 <span class="t-lc"><a href="c-chrono-time_t.html">time_t</a></span> 对象的当前日历时间，并将其存储于 <code>arg</code> 指向的 <span class="t-lc"><a href="c-chrono-time_t.html">time_t</a></span> 对象（除非 <code>arg</code> 为空指针）。</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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<table class="t-par-begin">
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<tr class="t-par">
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<td>arg</td>
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<td>-</td>
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<td>指向将存储时间的 <span class="t-lc"><a href="c-chrono-time_t.html">time_t</a></span> 对象的指针，或空指针</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>成功时返回编码成 <span class="t-lc"><a href="c-chrono-time_t.html">time_t</a></span> 对象的当前日历时间。错误时返回 <span class="t-c"><span class="mw-geshi c source-c"><span class="br0">(</span><a href="c-chrono-time_t.html"><span class="kw523">time_t</span></a><span class="br0">)</span><span class="br0">(</span><span class="sy2">-</span><span class="nu0">1</span><span class="br0">)</span></span></span> 。若<code>arg</code>不是空指针，则返回值也会存储于 <code>arg</code> 所指向的对象。</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>日历时间在 <span class="t-lc"><a href="c-chrono-time_t.html">time_t</a></span> 中的编码是未指定的，但多数系统遵循 <a rel="nofollow" class="external text" href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/time.html">POSIX 规定</a>，返回保有从<a rel="nofollow" class="external text" href="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_15">纪元</a>开始至今秒数的整数类型值。 <span class="t-lc"><a href="c-chrono-time_t.html">time_t</a></span> 为32位有符号整数的实现（许多历史上的实现）会在 <a rel="nofollow" class="external text" href="https://en.wikipedia.org/wiki/Year_2038_problem">2038</a> 年出错。</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="c source-c">
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<pre class="de1"><span class="co2">#include <stdio.h></span>
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<span class="co2">#include <time.h></span>
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<span class="co2">#include <stdint.h></span>
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<span class="kw4">int</span> main<span class="br0">(</span><span class="kw4">void</span><span class="br0">)</span>
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<span class="br0">{</span>
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<a href="c-chrono-time_t.html"><span class="kw523">time_t</span></a> result <span class="sy1">=</span> time<span class="br0">(</span><a href="c-types-NULL.html"><span class="kw103">NULL</span></a><span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">if</span><span class="br0">(</span>result <span class="sy3">!</span><span class="sy1">=</span> <span class="br0">(</span><a href="c-chrono-time_t.html"><span class="kw523">time_t</span></a><span class="br0">)</span><span class="br0">(</span><span class="sy2">-</span><span class="nu0">1</span><span class="br0">)</span><span class="br0">)</span>
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<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"The current time is %s(%jd seconds since the Epoch)<span class="es1">\n</span>"</span>,
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<a href="c-chrono-asctime.html"><span class="kw514">asctime</span></a><span class="br0">(</span><a href="c-chrono-gmtime.html"><span class="kw518">gmtime</span></a><span class="br0">(</span><span class="sy3">&</span>result<span class="br0">)</span><span class="br0">)</span>, <span class="br0">(</span><a href="c-types-integer.html"><span class="kw118">intmax_t</span></a><span class="br0">)</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>可能的输出：</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">The current time is Fri Apr 24 15:05:25 2015
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(1429887925 seconds since the Epoch)</pre></div>
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</div>
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</div>
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<h3><span class="mw-headline" id=".E5.BC.95.E7.94.A8">引用</span></h3>
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<div class="t-ref-std-11">
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<ul>
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<li>C11 标准（ISO/IEC 9899:2011）：</li>
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</ul>
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<dl>
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<dd>
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<ul>
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<li>7.27.2.4 The time function (p: 391)</li>
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</ul>
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</dd>
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</dl>
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<div class="t-ref-std-c99">
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<ul>
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<li>C99 标准（ISO/IEC 9899:1999）：</li>
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</ul>
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<dl>
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<dd>
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<ul>
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<li>7.23.2.4 The time function (p: 341)</li>
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</ul>
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</dd>
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</dl>
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<div class="t-ref-std-c89">
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<ul>
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<li>C89/C90 标准（ISO/IEC 9899:1990）：</li>
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</ul>
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<dl>
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<dd>
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<ul>
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<li>4.12.2.4 The time function</li>
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</ul>
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</dd>
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</dl>
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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">
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<div><a href="c-chrono-localtime.html"><span class="t-lines"><span>localtime</span><span>localtime_r</span><span>localtime_s</span></span></a></div>
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<div><span class="t-lines"><span></span><span><span class="t-mark-rev t-since-c23">(C23)</span></span><span><span class="t-mark-rev t-since-c11">(C11)</span></span></span></div>
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</div>
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</td>
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<td>将从纪元开始的时间转换成以本地时间表示的日历时间<br />
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<span class="t-mark">(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="c-chrono-gmtime.html"><span class="t-lines"><span>gmtime</span><span>gmtime_r</span><span>gmtime_s</span></span></a></div>
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<div><span class="t-lines"><span></span><span><span class="t-mark-rev t-since-c23">(C23)</span></span><span><span class="t-mark-rev t-since-c11">(C11)</span></span></span></div>
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</div>
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</td>
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<td>将从纪元开始的时间转换成以协调世界时（UTC）表示的日历时间<br />
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<span class="t-mark">(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="c-chrono-timespec_get.html"><span class="t-lines"><span>timespec_get</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-c11">(C11)</span></span></span></div>
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</div>
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</td>
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<td>返回基于给定时间基底的日历时间<br />
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<span class="t-mark">(函数)</span></td>
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</tr>
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</table>
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</div>
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</div>
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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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