235 lines
20 KiB
HTML
235 lines
20 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>wcsrtombs, wcsrtombs_s</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_string_multibyte_wcsrtombs 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">wcsrtombs, wcsrtombs_s</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-multibyte.html">multibyte</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><wchar.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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</tbody>
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<tbody class="t-dcl-rev t-dcl-rev-num">
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<tr class="t-dcl-rev-aux">
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<td></td>
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<td rowspan="142">(1)</td>
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<td></td>
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</tr>
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<tr class="t-dcl t-since-c95 t-until-c99">
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<td>
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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> wcsrtombs<span class="br0">(</span> <span class="kw4">char</span> <span class="sy2">*</span>dst, <span class="kw4">const</span> <span class="kw4">wchar_t</span> <span class="sy2">**</span>src, <a href="c-types-size_t.html"><span class="kw100">size_t</span></a> len, <a href="c-string-multibyte-mbstate_t.html"><span class="kw591">mbstate_t</span></a><span class="sy2">*</span> ps <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-c95">(C95 起)</span><br />
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<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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<td>
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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> wcsrtombs<span class="br0">(</span> <span class="kw4">char</span> <span class="sy2">*</span><span class="kw4">restrict</span> dst, <span class="kw4">const</span> <span class="kw4">wchar_t</span> <span class="sy2">**</span><span class="kw4">restrict</span> src, <a href="c-types-size_t.html"><span class="kw100">size_t</span></a> len,<br />
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<a href="c-string-multibyte-mbstate_t.html"><span class="kw591">mbstate_t</span></a> <span class="sy2">*</span><span class="kw4">restrict</span> ps <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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</tbody>
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<tbody>
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<tr class="t-dcl t-since-c11">
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<td>
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<div><span class="mw-geshi c source-c">errno_t wcsrtombs_s<span class="br0">(</span> <a href="c-types-size_t.html"><span class="kw100">size_t</span></a> <span class="sy2">*</span><span class="kw4">restrict</span> retval, <span class="kw4">char</span> <span class="sy2">*</span><span class="kw4">restrict</span> dst, rsize_t dstsz,<br /></span>
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<p> <span class="kw4">const</span> <span class="kw4">wchar_t</span> <span class="sy2">**</span><span class="kw4">restrict</span> src, rsize_t len,<br /></p>
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<a href="c-string-multibyte-mbstate_t.html"><span class="kw591">mbstate_t</span></a> <span class="sy2">*</span><span class="kw4">restrict</span> ps<span class="br0">)</span><span class="sy4">;</span></div>
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</td>
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<td>(2)</td>
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<td><span class="t-mark-rev t-since-c11">(C11 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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</tr>
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</tbody>
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</table>
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<div class="t-li1"><span class="t-li">1)</span> 转换来自元素为 <span class="t-c"><span class="mw-geshi c source-c"><span class="sy2">*</span>src</span></span> 所指向的宽字符序列为其窄多字节表示，始于 <span class="t-c"><span class="mw-geshi c source-c"><span class="sy2">*</span>ps</span></span> 所描述的转换状态。若 <code>dst</code> 非空，则存储转换后的字符于 <code>dst</code> 所指向的字符数组的相接元素。不写入多于 <code>len</code> 个字节到目标数组。如同以调用 <span class="t-lc"><a href="c-string-multibyte-wcrtomb.html">wcrtomb</a></span> 转换每个字符。若遇到下列条件则停止转换：
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<ul>
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<li>转换并存储了空字符 <span class="t-c"><span class="mw-geshi c source-c">L<span class="st0">'<span class="es5">\0</span>'</span></span></span> 。此情况下存储的字节是反迁移序列（若需要）后随 <span class="t-c"><span class="mw-geshi c source-c"><span class="st0">'<span class="es5">\0</span>'</span></span></span> ，设置 <span class="t-c"><span class="mw-geshi c source-c"><span class="sy2">*</span>src</span></span> 为空指针值并令 <span class="t-c"><span class="mw-geshi c source-c"><span class="sy2">*</span>ps</span></span> 表示初始迁移状态。</li>
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<li>找到当前 C 本地环境中不对应合法字符的 <span class="t-c"><span class="mw-geshi c source-c"><span class="kw4">wchar_t</span></span></span> 。设置 <span class="t-c"><span class="mw-geshi c source-c"><span class="sy2">*</span>src</span></span> 指向首个未转换的宽字符。</li>
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<li>下个多字节字符将超出 <code>len</code> 。设置 <span class="t-c"><span class="mw-geshi c source-c"><span class="sy2">*</span>src</span></span> 指向首个未转换的宽字符。若 <code>dst</code> 为空指针则不检查此条件。</li>
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</ul>
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</div>
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<div class="t-li1"><span class="t-li">2)</span> 同 <span class="t-v">(1)</span> ，除了
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<ul>
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<li>函数返回其结果为输出参数 <code>retval</code></li>
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<li>若转换停止而不写入空字符，则函数将存储 <span class="t-c"><span class="mw-geshi c source-c"><span class="st0">'<span class="es5">\0</span>'</span></span></span> 于 <code>dst</code> 的下个字节，它可以是 <span class="t-c"><span class="mw-geshi c source-c">dst<span class="br0">[</span>len<span class="br0">]</span></span></span> 或 <span class="t-c"><span class="mw-geshi c source-c">dst<span class="br0">[</span>dstsz<span class="br0">]</span></span></span> ，两者的先到来者（表示总共可能写入 len+1/dstsz+1 字节）。此情况下，在终止空字符前可以无反迁移序列。</li>
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<li>函数从终止空字符 <code>dstsz</code> 到位置破坏数组</li>
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<li>若 <code>src</code> 与 <code>dst</code> 重叠，则行为未指定。</li>
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<li>在运行时检测下列错误并调用当前安装的<a href="c-error-set_constraint_handler_s.html">制约处理</a>函数：</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><code>retval</code> 、 <code>ps</code> 、 <code>src</code> 或 <span class="t-c"><span class="mw-geshi c source-c"><span class="sy2">*</span>src</span></span> 为空指针</li>
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<li><code>dstsz</code> 或 <code>len</code> 大于 <span class="t-lc">RSIZE_MAX</span> （除非 <code>dst</code> 为空）</li>
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<li><code>dstsz</code> 非零（除非 <code>dst</code> 为空）</li>
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<li><code>len</code> 大于 <code>dstsz</code> 且转换在抵达 <code>dstsz</code> 时于 <code>src</code> 数组中未遇到空字符或编码错误（除非 <code>dst</code> 为空）</li>
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</ul>
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</dd>
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<dd>同所有边界检查函数， <code>wcsrtombs_s</code> 仅若实现定义 <span class="t-c"><span class="mw-geshi c source-c">__STDC_LIB_EXT1__</span></span> 且用户在包含 <code>wchar.h</code> 前定义 <span class="t-c"><span class="mw-geshi c source-c">__STDC_WANT_LIB_EXT1__</span></span> 为整数常量 1 才保证可用。</dd>
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</dl>
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</div>
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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>dst</td>
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<td>-</td>
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<td>指向窄字符数组的指针，其中将存储多字节字符</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>指向指向空终止宽字符串首元素的指针的指针</td>
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</tr>
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<tr class="t-par">
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<td>len</td>
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<td>-</td>
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<td>dst 所指向的数组中可用的字节数</td>
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</tr>
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<tr class="t-par">
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<td>ps</td>
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<td>-</td>
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<td>指向转换状态对象的指针</td>
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</tr>
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<tr class="t-par">
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<td>dstsz</td>
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<td>-</td>
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<td>将写入的最大字节数（ <code>dst</code> 数组的大小）</td>
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</tr>
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<tr class="t-par">
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<td>retval</td>
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<td>-</td>
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<td>指向将存储结果于其中的 <code>size_t</code> 对象的指针</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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<div class="t-li1"><span class="t-li">1)</span> 成功时，返回写入首元素为 <code>dst</code> 所指向的字符数组的字节数（包含任何迁移序列，但不包含终止 <span class="t-c"><span class="mw-geshi c source-c"><span class="st0">'<span class="es5">\0</span>'</span></span></span> ）。若 <code>ds</code> 为空指针，则返回本会写入的字节数。错误时（若遇到非法宽字符），返回 <span class="t-c"><span class="mw-geshi c source-c"><span class="br0">(</span><a href="c-types-size_t.html"><span class="kw100">size_t</span></a><span class="br0">)</span><span class="sy2">-</span><span class="nu0">1</span></span></span> ，存储 <span class="t-lc"><a href="c-error-errno_macros.html">EILSEQ</a></span> 于 <span class="t-lc"><a href="c-error-errno.html">errno</a></span> ，并令 <span class="t-c"><span class="mw-geshi c source-c"><span class="sy2">*</span>ps</span></span> 留在未指定状态。</div>
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<div class="t-li1"><span class="t-li">2)</span> 成功时返回零（该情况下将不包含终止零写入或本会写入到 <code>dst</code> 的字符数存储于 <span class="t-c"><span class="mw-geshi c source-c"><span class="sy2">*</span>retval</span></span> ），错误时返回非零。在运行时制约违规的情况下，存储 <span class="t-c"><span class="mw-geshi c source-c"><span class="br0">(</span><a href="c-types-size_t.html"><span class="kw100">size_t</span></a><span class="br0">)</span><span class="sy2">-</span><span class="nu0">1</span></span></span> 于 <span class="t-c"><span class="mw-geshi c source-c"><span class="sy2">*</span>retval</span></span> （除非 <code>retval</code> 为空）并设置 <span class="t-c"><span class="mw-geshi c source-c">dst<span class="br0">[</span><span class="nu0">0</span><span class="br0">]</span></span></span> 为 <span class="t-c"><span class="mw-geshi c source-c"><span class="st0">'<span class="es5">\0</span>'</span></span></span> （除非 <code>dst</code> 为空或 <code>dstmax</code> 为零或大于 <span class="t-lc">RSIZE_MAX</span> ）。</div>
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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 <locale.h></span>
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<span class="co2">#include <string.h></span>
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<span class="co2">#include <wchar.h></span>
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<span class="kw4">void</span> print_wide<span class="br0">(</span><span class="kw4">const</span> <span class="kw4">wchar_t</span><span class="sy2">*</span> wstr<span class="br0">)</span>
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<span class="br0">{</span>
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<a href="c-string-multibyte-mbstate_t.html"><span class="kw591">mbstate_t</span></a> state<span class="sy4">;</span>
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<a href="c-string-byte-memset.html"><span class="kw571">memset</span></a><span class="br0">(</span><span class="sy3">&</span>state, <span class="nu0">0</span>, <span class="kw4">sizeof</span> state<span class="br0">)</span><span class="sy4">;</span>
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<a href="c-types-size_t.html"><span class="kw100">size_t</span></a> len <span class="sy1">=</span> <span class="nu0">1</span> <span class="sy2">+</span> wcsrtombs<span class="br0">(</span><a href="c-types-NULL.html"><span class="kw103">NULL</span></a>, <span class="sy3">&</span>wstr, <span class="nu0">0</span>, <span class="sy3">&</span>state<span class="br0">)</span><span class="sy4">;</span>
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<span class="kw4">char</span> mbstr<span class="br0">[</span>len<span class="br0">]</span><span class="sy4">;</span>
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wcsrtombs<span class="br0">(</span>mbstr, <span class="sy3">&</span>wstr, len, <span class="sy3">&</span>state<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">"Multibyte string: %s<span class="es1">\n</span>"</span>, mbstr<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">"Length, including '<span class="es1">\\</span>0': %d<span class="es1">\n</span>"</span>, len<span class="br0">)</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="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="kw903">LC_ALL</span></a>, <span class="st0">"en_US.utf8"</span><span class="br0">)</span><span class="sy4">;</span>
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print_wide<span class="br0">(</span>L<span class="st0">"z<span class="es3">\u00df</span><span class="es3">\u6c34</span><span class="es4">\U0001f34c</span>"</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// 或 L"zß水🍌"</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">Multibyte string: zß水🍌
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Length, including '\0': 11</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>7.29.6.4.2 The wcsrtombs function (p: 446)</li>
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</ul>
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</dd>
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</dl>
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<dl>
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<dd>
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<ul>
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<li>K.3.9.3.2.2 The wcsrtombs_s function (p: 649-651)</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>7.24.6.4.2 The wcsrtombs function (p: 392)</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-multibyte-wcstombs.html"><span class="t-lines"><span>wcstombs</span><span>wcstombs_s</span></span></a></div>
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<div><span class="t-lines"><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>将宽字符串转换成窄多字节字符串<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-multibyte-wcrtomb.html"><span class="t-lines"><span>wcrtomb</span><span>wcrtomb_s</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><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>给定状态，将宽字符转换成其多字节表示<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-multibyte-mbsrtowcs.html"><span class="t-lines"><span>mbsrtowcs</span><span>mbsrtowcs_s</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><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>给定状态，将窄多字节字符串转换成宽字符串<br />
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<span class="t-mark">(函数)</span></td>
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</tr>
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</table>
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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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