143 lines
10 KiB
HTML
143 lines
10 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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<title>std::wcstok</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_string_wide_wcstok 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>wcstok</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-string.html">string</a>‎ | <a href="cpp-string-wide.html">wide</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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<div>定义于头文件 <code><a href="cpp-header-cwchar.html"><cwchar></a></code></div>
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<td></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">wchar_t</span><span class="sy2">*</span> wcstok<span class="br0">(</span> <span class="kw4">wchar_t</span><span class="sy2">*</span> str, <span class="kw4">const</span> <span class="kw4">wchar_t</span><span class="sy2">*</span> delim, <span class="kw4">wchar_t</span> <span class="sy2">**</span> ptr<span class="br0">)</span><span class="sy4">;</span></span></div>
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<td class="t-dcl-nopad"></td>
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<td></td>
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<p>寻找 <code>str</code> 所指向的空终止宽字符串中的下个记号。以 <code>delim</code> 所指向的空终止宽字符串鉴别分隔符。</p>
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<div class="t-li1"><span class="t-li"></span> 此函数被设计为调用多次以从同一字符串获得相继的记号。</div>
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<dl>
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<dd>
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<li>若 <span class="t-c"><span class="mw-geshi cpp source-cpp">str <span class="sy3">!</span><span class="sy1">=</span> <a href="cpp-types-NULL.html"><span class="kw103">NULL</span></a></span></span> ，则调用被当做 <code>std::wcstok</code> 首次对此具体宽字符的调用。函数搜索首个<i>不</i>含于 <code>delim</code> 的字符。</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>若找不到这种宽字符，则 <code>str</code> 中完全无记号，而函数返回空指针。</li>
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<li>若找到这种宽字符，则它是<i>记号起始</i>。然后函数从该点搜索首个<i>含于</i> <code>delim</code> 的宽字符。</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>若找不到这种宽字符，则 <code>str</code> 只有一个记号，而对 <code>std::wcstok</code> 的将来调用将返回空指针</li>
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<li>若找到这种宽字符，则以空宽字符 <span class="t-c"><span class="mw-geshi cpp source-cpp">L<span class="st0">'<span class="es5">\0</span>'</span></span></span> <i>替换</i>它，并存储分析状态（典型地为指向后一宽字符的指针）于用户提供位置 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>ptr</span></span> 。</li>
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</ul>
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</dd>
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</dl>
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<ul>
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<li>然后函数返回指向记号起始的指针</li>
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</ul>
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</dd>
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</dl>
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<ul>
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<li>若 <span class="t-c"><span class="mw-geshi cpp source-cpp">str <span class="sy1">==</span> <a href="cpp-types-NULL.html"><span class="kw103">NULL</span></a></span></span> ，则调用被当作对 <code>std::wcstok</code> 的后继调用：函数从带同一 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>ptr</span></span> 的先前调用所留下的位置开始持续。行为与如同将指向后随上次检测的记号的宽字符的指针作为 <span class="t-c"><span class="mw-geshi cpp source-cpp">str</span></span> 传递相同。</li>
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</ul>
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</dd>
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</dl>
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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>str</td>
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<td>-</td>
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<td>指向要记号化的空终止宽字符串的指针</td>
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</tr>
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<tr class="t-par">
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<td>delim</td>
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<td>-</td>
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<td>指向标识分隔符的空终止宽字符串的指针</td>
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</tr>
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<tr class="t-par">
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<td>ptr</td>
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<td>-</td>
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<td>指向 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">wchar_t</span><span class="sy2">*</span></span></span> 类型对象的指针， <code>wcstok</code> 以之存储分析器的内部状态</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>返回指向下个记号起始的指针，或若无更多记号则为空指针。</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>此函数是破坏性的：它写入 <span class="t-c"><span class="mw-geshi cpp source-cpp">L<span class="st0">'<span class="es5">\0</span>'</span></span></span> 字符于字符串 <code>str</code> 的元素。特别是，宽字符串字面量不能用作 <code>std::wcstok</code> 的首参数。</p>
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<p>不同于 <span class="t-lc"><a href="cpp-string-byte-strtok.html">std::strtok</a></span> ，此函数不更新静态存储：它存储分析状态于用户提供的位置。</p>
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<p>不同于大多数其他记号化器， <code>std::wcstok</code> 中的分隔符能对于后继记号不同，而且甚至能依赖于先前记号的内容。</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 <cwchar></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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<span class="kw4">wchar_t</span> input<span class="br0">[</span><span class="nu0">100</span><span class="br0">]</span> <span class="sy1">=</span> L<span class="st0">"A bird came down the walk"</span><span class="sy4">;</span>
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<span class="kw4">wchar_t</span><span class="sy2">*</span> buffer<span class="sy4">;</span>
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<span class="kw4">wchar_t</span><span class="sy2">*</span> token <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">wcstok</span><span class="br0">(</span>input, L<span class="st0">" "</span>, <span class="sy3">&</span>buffer<span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">while</span> <span class="br0">(</span>token<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">wcout</span></span></a> <span class="sy1"><<</span> token <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
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token <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">wcstok</span><span class="br0">(</span>nullptr, L<span class="st0">" "</span>, <span class="sy3">&</span>buffer<span class="br0">)</span><span class="sy4">;</span>
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<span class="br0">}</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">A
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bird
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came
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down
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the
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walk</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-string-byte-strtok.html"><span class="t-lines"><span>strtok</span></span></a></div>
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</div>
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</td>
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<td>寻找字节字符串中的下个记号<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 class="visualClear"></div>
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</div>
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</div>
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</body>
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