118 lines
6.2 KiB
HTML
118 lines
6.2 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>std::basic_ios<CharT,Traits>::rdstate</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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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_io_basic_ios_rdstate 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"><span style="font-size:0.7em; line-height:130%">std::basic_ios<CharT,Traits>::</span>rdstate</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-io.html">io</a>‎ | <a href="cpp-io-basic_ios.html">basic ios</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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<div><span class="mw-geshi cpp source-cpp">iostate rdstate<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></div>
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<td class="t-dcl-nopad"></td>
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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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<td></td>
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</tr>
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</tbody>
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</table>
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<p>返回当前错误状态。</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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<p>（无）</p>
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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>当前错误状态。它是位掩码类型，并且能是下列常量的组合：</p>
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<table class="t-dsc-begin">
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<tr class="t-dsc-hitem">
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<td>常量</td>
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<td>解释</td>
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</tr>
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<tr class="t-dsc">
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<td><a href="cpp-io-ios_base-iostate.html"><tt>goodbit</tt></a></td>
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<td>无错误</td>
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</tr>
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<tr class="t-dsc">
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<td><a href="cpp-io-ios_base-iostate.html"><tt>badbit</tt></a></td>
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<td>不可恢复的流错误</td>
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</tr>
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<tr class="t-dsc">
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<td><a href="cpp-io-ios_base-iostate.html"><tt>failbit</tt></a></td>
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<td>输入/输出操作失败（格式化或提取错误）</td>
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</tr>
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<tr class="t-dsc">
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<td><a href="cpp-io-ios_base-iostate.html"><tt>eofbit</tt></a></td>
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<td>关联的输出序列已抵达文件尾</td>
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</tr>
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</table>
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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 <sstream></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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<a href="cpp-io-basic_ostringstream.html"><span class="kw1736">std::<span class="me2">ostringstream</span></span></a> stream<span class="sy4">;</span>
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<span class="kw1">if</span> <span class="br0">(</span>stream.<span class="me1">rdstate</span><span class="br0">(</span><span class="br0">)</span> <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="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">"stream state is goodbit<span class="es1">\n</span>"</span><span class="sy4">;</span>
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<span class="br0">}</span>
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stream.<span class="me1">setstate</span><span class="br0">(</span><a href="cpp-io-ios_base-iostate.html"><span class="kw1701">std::<span class="me2">ios_base</span><span class="sy4">::</span><span class="me2">eofbit</span></span></a><span class="br0">)</span><span class="sy4">;</span>
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<span class="co1">// 检查状态为准确的 eofbit （无 failbit 且无 badbit ）</span>
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<span class="kw1">if</span> <span class="br0">(</span>stream.<span class="me1">rdstate</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">==</span> <a href="cpp-io-ios_base-iostate.html"><span class="kw1701">std::<span class="me2">ios_base</span><span class="sy4">::</span><span class="me2">eofbit</span></span></a><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">"stream state is eofbit<span class="es1">\n</span>"</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">stream state is goodbit
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stream state is eofbit</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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<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="cpp-io-basic_ios-setstate.html"><span class="t-lines"><span>setstate</span></span></a></div>
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</div>
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</td>
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<td>设置状态标志<br />
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<span class="t-mark">(公开成员函数)</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="cpp-io-basic_ios-clear.html"><span class="t-lines"><span>clear</span></span></a></div>
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</div>
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</td>
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<td>修改状态标志<br />
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<span class="t-mark">(公开成员函数)</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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</div>
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</body>
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</html>
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