167 lines
17 KiB
HTML
167 lines
17 KiB
HTML
<!DOCTYPE html>
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<title>std::time_get<CharT,InputIt>::get_year, std::time_get<CharT,InputIt>::do_get_year</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_locale_time_get_get_year 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::time_get<CharT,InputIt>::</span>get_year, <span style="font-size:0.7em; line-height:130%">std::time_get<CharT,InputIt>::</span>do_get_year</h1>
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-locale.html">locale</a>‎ | <a href="cpp-locale-time_get.html">time get</a></span></div>
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<div>定义于头文件 <code><a href="cpp-header-locale.html"><locale></a></code></div>
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<td></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">public</span><span class="sy4">:</span><br /></span>
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<p>iter_type do_get_year<span class="br0">(</span> iter_type s, iter_type end, <a href="cpp-io-ios_base.html"><span class="kw1669">std::<span class="me2">ios_base</span></span></a><span class="sy3">&</span> str,<br /></p>
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<a href="cpp-io-ios_base-iostate.html"><span class="kw1697">std::<span class="me2">ios_base</span><span class="sy4">::</span><span class="me2">iostate</span></span></a><span class="sy3">&</span> err, <a href="cpp-chrono-c-tm.html"><span class="kw1023">std::<span class="me2">tm</span></span></a><span class="sy2">*</span> t<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></div>
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<td>(1)</td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">protected</span><span class="sy4">:</span><br /></span>
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<p><span class="kw1">virtual</span> iter_type do_get_year<span class="br0">(</span> iter_type s, iter_type end, <a href="cpp-io-ios_base.html"><span class="kw1669">std::<span class="me2">ios_base</span></span></a><span class="sy3">&</span> str,<br /></p>
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<a href="cpp-io-ios_base-iostate.html"><span class="kw1697">std::<span class="me2">ios_base</span><span class="sy4">::</span><span class="me2">iostate</span></span></a><span class="sy3">&</span> err, <a href="cpp-chrono-c-tm.html"><span class="kw1023">std::<span class="me2">tm</span></span></a><span class="sy2">*</span> t<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></div>
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<td>(2)</td>
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<div class="t-li1"><span class="t-li">1)</span> 公开成员函数，调用最终导出类的受保护虚成员函数 <code>do_get_year</code> 。</div>
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<div class="t-li1"><span class="t-li">2)</span> 读取来自序列 <code>[beg, end)</code> 的相继字符，用某实现定义格式分析出年。取决于 locale ，可能接受二位的年，而它们属于哪个世纪是实现定义的。</div>
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<p>存储分析而得的年于 <span class="t-lc"><a href="cpp-chrono-c-tm.html">std::tm</a></span> 结构体域 <span class="t-c"><span class="mw-geshi cpp source-cpp">t<span class="sy2">-</span><span class="sy1">></span>tm_year</span></span> 。</p>
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<p>若在读到合法日期前抵达尾迭代器，则函数设置 <code>err</code> 中的 <span class="t-lc"><a href="cpp-io-ios_base-iostate.html">std::ios_base::eofbit</a></span> 。若遇到分析错误，则函数设置 <code>err</code> 中的 <span class="t-lc"><a href="cpp-io-ios_base-iostate.html">std::ios_base::failbit</a></span> 。</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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<td>beg</td>
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<td>-</td>
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<td>指代要分析的序列起始的迭代器</td>
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<tr class="t-par">
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<td>end</td>
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<td>-</td>
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<td>要分析的序列的尾后一位置迭代器</td>
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<td>str</td>
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<td>-</td>
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<td>此函数在需要时用以获得 locale 平面的流对象，例如用 <span class="t-lc"><a href="cpp-locale-ctype.html">std::ctype</a></span> 跳过空白符或用 <span class="t-lc"><a href="cpp-locale-collate.html">std::collate</a></span> 比较字符串</td>
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<td>err</td>
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<td>-</td>
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<td>此函数所修改以指示错误的流错误标志对象</td>
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<tr class="t-par">
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<td>t</td>
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<td>-</td>
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<td>指向 <span class="t-lc"><a href="cpp-chrono-c-tm.html">std::tm</a></span> 对象的指针，该对象将保有此函数调用结果</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>指向 <code>[beg, end)</code> 中辨识为合法年一部分的末字符后一位置的迭代器。</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>对于二位输入值，许多实现使用同 <span class="t-lc"><a href="cpp-io-manip-get_time.html">std::get_time</a></span> 、 <span class="t-lc"><a href="cpp-locale-time_get-get.html">std::time_get::get()</a></span> 和 POSIX 函数 <code>strptime()</code> 所用的转换指定符 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="st0">'%y'</span></span></span> 的分析规则：期待二位整数，范围 [69,99] 中的值导致值 1969 到 1999 ，范围 [00,68] 导致 2000-2068 。四位输入典型地保持原状接受。</p>
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<p>若遇到分析错误，则此函数的大多数实现保留 <code>*t</code> 不修改。</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 <iostream></span>
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<span class="co2">#include <locale></span>
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<span class="co2">#include <sstream></span>
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<span class="co2">#include <iterator></span>
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<span class="kw4">void</span> try_get_year<span class="br0">(</span><span class="kw4">const</span> <a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a><span class="sy3">&</span> s<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">"Parsing the year out of '"</span> <span class="sy1"><<</span> s <span class="sy1"><<</span>
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<span class="st0">"' in the locale "</span> <span class="sy1"><<</span> <a href="cpp-locale-locale.html"><span class="kw1894">std::<span class="me2">locale</span></span></a><span class="br0">(</span><span class="br0">)</span>.<span class="me1">name</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
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<a href="cpp-io-basic_istringstream.html"><span class="kw1735">std::<span class="me2">istringstream</span></span></a> str<span class="br0">(</span>s<span class="br0">)</span><span class="sy4">;</span>
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<a href="cpp-io-ios_base-iostate.html"><span class="kw1697">std::<span class="me2">ios_base</span><span class="sy4">::</span><span class="me2">iostate</span></span></a> err <span class="sy1">=</span> <a href="cpp-io-ios_base-iostate.html"><span class="kw1698">std::<span class="me2">ios_base</span><span class="sy4">::</span><span class="me2">goodbit</span></span></a><span class="sy4">;</span>
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<a href="cpp-chrono-c-tm.html"><span class="kw1023">std::<span class="me2">tm</span></span></a> t<span class="sy4">;</span>
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<a href="cpp-iterator-istreambuf_iterator.html"><span class="kw669">std::<span class="me2">istreambuf_iterator</span></span></a><span class="sy1"><</span><span class="kw4">char</span><span class="sy1">></span> ret <span class="sy1">=</span>
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<a href="cpp-locale-use_facet.html"><span class="kw1897">std::<span class="me2">use_facet</span></span></a><span class="sy1"><</span><a href="cpp-locale-time_get.html"><span class="kw1949">std::<span class="me2">time_get</span></span></a><span class="sy1"><</span><span class="kw4">char</span><span class="sy1">>></span><span class="br0">(</span>str.<span class="me1">getloc</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span>.<span class="me1">get_year</span><span class="br0">(</span>
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<span class="br0">{</span>str<span class="br0">}</span>, <span class="br0">{</span><span class="br0">}</span>, str, err, <span class="sy3">&</span>t
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<span class="br0">)</span><span class="sy4">;</span>
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str.<span class="me1">setstate</span><span class="br0">(</span>err<span class="br0">)</span><span class="sy4">;</span>
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<a href="cpp-iterator-istreambuf_iterator.html"><span class="kw669">std::<span class="me2">istreambuf_iterator</span></span></a><span class="sy1"><</span><span class="kw4">char</span><span class="sy1">></span> last<span class="br0">{</span><span class="br0">}</span><span class="sy4">;</span>
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<span class="kw1">if</span> <span class="br0">(</span>str<span class="br0">)</span> <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">"Successfully parsed, year is "</span> <span class="sy1"><<</span> <span class="nu0">1900</span> <span class="sy2">+</span> t.<span class="me1">tm_year</span><span class="sy4">;</span>
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<span class="kw1">if</span> <span class="br0">(</span>ret <span class="sy3">!</span><span class="sy1">=</span> last<span class="br0">)</span> <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">" Remaining content: "</span><span class="sy4">;</span>
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<a href="cpp-algorithm-copy.html"><span class="kw1582">std::<span class="me2">copy</span></span></a><span class="br0">(</span>ret, last, <a href="cpp-iterator-ostreambuf_iterator.html"><span class="kw671">std::<span class="me2">ostreambuf_iterator</span></span></a><span class="sy1"><</span><span class="kw4">char</span><span class="sy1">></span><span class="br0">(</span><a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="br0">}</span> <span class="kw1">else</span> <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">" the input was fully consumed"</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="br0">}</span> <span class="kw1">else</span> <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">"Parse failed. Unparsed string: "</span><span class="sy4">;</span>
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<a href="cpp-algorithm-copy.html"><span class="kw1582">std::<span class="me2">copy</span></span></a><span class="br0">(</span>ret, last, <a href="cpp-iterator-ostreambuf_iterator.html"><span class="kw671">std::<span class="me2">ostreambuf_iterator</span></span></a><span class="sy1"><</span><span class="kw4">char</span><span class="sy1">></span><span class="br0">(</span><a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</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">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
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<span class="br0">}</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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std<span class="sy4">::</span><span class="me2">locale</span><span class="sy4">::</span><span class="me2">global</span><span class="br0">(</span><a href="cpp-locale-locale.html"><span class="kw1894">std::<span class="me2">locale</span></span></a><span class="br0">(</span><span class="st0">"en_US.utf8"</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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try_get_year<span class="br0">(</span><span class="st0">"13"</span><span class="br0">)</span><span class="sy4">;</span>
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try_get_year<span class="br0">(</span><span class="st0">"2013"</span><span class="br0">)</span><span class="sy4">;</span>
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std<span class="sy4">::</span><span class="me2">locale</span><span class="sy4">::</span><span class="me2">global</span><span class="br0">(</span><a href="cpp-locale-locale.html"><span class="kw1894">std::<span class="me2">locale</span></span></a><span class="br0">(</span><span class="st0">"ja_JP.utf8"</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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try_get_year<span class="br0">(</span><span class="st0">"2013年"</span><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">Parsing the year out of '13' in the locale en_US.utf8
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Successfully parsed, year is 2013 the input was fully consumed
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Parsing the year out of '2013' in the locale en_US.utf8
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Successfully parsed, year is 2013 the input was fully consumed
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Parsing the year out of '2013年' in the locale ja_JP.utf8
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Successfully parsed, year is 2013 Remaining content: 年</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-io-manip-get_time.html"><span class="t-lines"><span>get_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>剖析指定格式的日期/时间值<br />
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<span class="t-mark">(函数模板)</span></td>
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</table>
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<div class="visualClear"></div>
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