202 lines
13 KiB
HTML
202 lines
13 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>strxfrm</title>
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</head>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-c_string_byte_strxfrm 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">strxfrm</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-string.html">string</a>‎ | <a href="c-string-byte.html">byte</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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<td>
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<div>定义于头文件 <code><string.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 t-until-c99">
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<div><span class="mw-geshi c source-c"><a href="c-types-size_t.html"><span class="kw100">size_t</span></a> strxfrm<span class="br0">(</span> <span class="kw4">char</span> <span class="sy2">*</span>dest, <span class="kw4">const</span> <span class="kw4">char</span> <span class="sy2">*</span>src,<br />
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<a href="c-types-size_t.html"><span class="kw100">size_t</span></a> count <span class="br0">)</span><span class="sy4">;</span></span></div>
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</td>
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<td class="t-dcl-nopad"></td>
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<td><span class="t-mark-rev t-until-c99">(C99 前)</span></td>
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</tr>
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<tr class="t-dcl t-since-c99">
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<div><span class="mw-geshi c source-c"><a href="c-types-size_t.html"><span class="kw100">size_t</span></a> strxfrm<span class="br0">(</span> <span class="kw4">char</span> <span class="sy2">*</span><span class="kw4">restrict</span> dest, <span class="kw4">const</span> <span class="kw4">char</span> <span class="sy2">*</span><span class="kw4">restrict</span> src,<br />
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<a href="c-types-size_t.html"><span class="kw100">size_t</span></a> count <span class="br0">)</span><span class="sy4">;</span></span></div>
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</td>
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<td class="t-dcl-nopad"></td>
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<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
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</tr>
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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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<td></td>
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</tbody>
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<p>变换 <code>src</code> 所指向的空终止字节字符串为实现定义形式,满足当前 C 本地环境中,以 <span class="t-lc"><a href="c-string-byte-strcmp.html">strcmp</a></span> 比较二个变换后字符串给出与用 <span class="t-lc"><a href="c-string-byte-strcoll.html">strcoll</a></span> 比较源字符串相同的结果。</p>
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<p>将变换后字符串的首 <code>count</code> 个字符写入目标,包含空终止字符,并返回排除空终止字符的完整转换后字符串的长度。</p>
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<p>若 <code>dest</code> 数组不够大则行为未定义。若 <code>dest</code> 与 <code>src</code> 重叠则行为未定义。</p>
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<p>若 <code>count</code> 为 <span class="t-c"><span class="mw-geshi c source-c">​<span class="nu0">0</span>​</span></span> ,则允许 <code>dest</code> 为空指针。</p>
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<p>在以同一字符串或字符串集合进行多个本地环境依赖的比较时,使用此函数,因为仅用 <code>strxfrm</code> 变换所有字符串一次,而以 <span class="t-lc"><a href="c-string-byte-strcmp.html">strcmp</a></span> 进行后继比较更为高效。</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>能接收整个变换后字符串的正确缓冲区长度为 <span class="t-c"><span class="mw-geshi c source-c"><span class="nu0">1</span><span class="sy2">+</span>strxfrm<span class="br0">(</span><a href="c-types-NULL.html"><span class="kw103">NULL</span></a>, src, <span class="nu0">0</span><span class="br0">)</span></span></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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<tr class="t-par">
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<td>dest</td>
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<td>-</td>
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<td>指向将写入变换后的字符串的数组首元素的指针</td>
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</tr>
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<tr class="t-par">
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<td>src</td>
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<td>-</td>
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<td>指向要变换的空终止字节字符串首元素的指针</td>
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</tr>
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<tr class="t-par">
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<td>count</td>
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<td>-</td>
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<td>要写入的最大字符数</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>变换后的字符串长度,不包含空终止字符。</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 <string.h></span>
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<span class="co2">#include <locale.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-locale-setlocale.html"><span class="kw900">setlocale</span></a><span class="br0">(</span><a href="c-locale-LC_categories.html"><span class="kw904">LC_COLLATE</span></a>, <span class="st0">"cs_CZ.iso88592"</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="kw4">const</span> <span class="kw4">char</span> <span class="sy2">*</span>in1 <span class="sy1">=</span> <span class="st0">"hrnec"</span><span class="sy4">;</span>
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<span class="kw4">char</span> out1<span class="br0">[</span><span class="nu0">1</span><span class="sy2">+</span>strxfrm<span class="br0">(</span><a href="c-types-NULL.html"><span class="kw103">NULL</span></a>, in1, <span class="nu0">0</span><span class="br0">)</span><span class="br0">]</span><span class="sy4">;</span>
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strxfrm<span class="br0">(</span>out1, in1, <span class="kw4">sizeof</span> out1<span class="br0">)</span><span class="sy4">;</span>
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<span class="kw4">const</span> <span class="kw4">char</span> <span class="sy2">*</span>in2 <span class="sy1">=</span> <span class="st0">"chrt"</span><span class="sy4">;</span>
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<span class="kw4">char</span> out2<span class="br0">[</span><span class="nu0">1</span><span class="sy2">+</span>strxfrm<span class="br0">(</span><a href="c-types-NULL.html"><span class="kw103">NULL</span></a>, in2, <span class="nu0">0</span><span class="br0">)</span><span class="br0">]</span><span class="sy4">;</span>
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strxfrm<span class="br0">(</span>out2, in2, <span class="kw4">sizeof</span> out2<span class="br0">)</span><span class="sy4">;</span>
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<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"In the Czech locale: "</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">if</span><span class="br0">(</span><a href="c-string-byte-strcmp.html"><span class="kw558">strcmp</span></a><span class="br0">(</span>out1, out2<span class="br0">)</span> <span class="sy1"><</span> <span class="nu0">0</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">"%s before %s<span class="es1">\n</span>"</span>,in1, in2<span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">else</span>
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<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"%s before %s<span class="es1">\n</span>"</span>,in2, in1<span class="br0">)</span><span class="sy4">;</span>
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<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"In lexicographical comparison: "</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">if</span><span class="br0">(</span><a href="c-string-byte-strcmp.html"><span class="kw558">strcmp</span></a><span class="br0">(</span>in1, in2<span class="br0">)</span><span class="sy1"><</span><span class="nu0">0</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">"%s before %s<span class="es1">\n</span>"</span>,in1, in2<span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">else</span>
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<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"%s before %s<span class="es1">\n</span>"</span>,in2, in1<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">In the Czech locale: hrnec before chrt
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In lexicographical comparison: chrt before hrnec</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>7.24.4.5 The strxfrm function (p: 366-367)</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>7.21.4.5 The strxfrm function (p: 329-330)</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>4.11.4.5 The strxfrm 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-string-byte-strcoll.html"><span class="t-lines"><span>strcoll</span></span></a></div>
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</div>
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</td>
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<td>比较两个字符串,根据当前本地环境<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-string-wide-wcscoll.html"><span class="t-lines"><span>wcscoll</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-c95">(C95)</span></span></span></div>
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</div>
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</td>
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<td>根据当前本地环境比较两个宽字符串<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-string-byte-strcmp.html"><span class="t-lines"><span>strcmp</span></span></a></div>
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</div>
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</td>
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<td>比较两个字符串<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-string-wide-wcsxfrm.html"><span class="t-lines"><span>wcsxfrm</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-c95">(C95)</span></span></span></div>
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</div>
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</td>
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<td>变换宽字符串,使得 <code>wcscmp</code> 会产生与 <code>wcscoll</code> 相同的结果<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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