157 lines
8.3 KiB
HTML
157 lines
8.3 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>feof</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_io_feof 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">feof</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-io.html">io</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><stdio.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">
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<td class="t-dcl-nopad">
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<div><span class="mw-geshi c source-c"><span class="kw4">int</span> feof<span class="br0">(</span> <a href="c-io.html"><span class="kw883">FILE</span></a> <span class="sy2">*</span>stream <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 class="t-dcl-nopad"></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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<p>检查是否已抵达给定文件流的结尾。</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>stream</td>
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<td>-</td>
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<td>要检验的文件流</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>若已抵达流尾则为非零值，否则为 <span class="t-c"><span class="mw-geshi c source-c">​<span class="nu0">0</span>​</span></span></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>此函数仅报告最近一次 I/O 操作所报告的流状态，而不检验关联的数据源。例如，若最近一次 I/O 是抵达文件最后字节的 <span class="t-lc"><a href="c-io-fgetc.html">fgetc</a></span> ，则 <code>feof</code> 返回零。下个 <span class="t-lc"><a href="c-io-fgetc.html">fgetc</a></span> 失败并更改流状态为<i>文件尾</i>。然后 <code>feof</code> 才返回非零。</p>
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<p>典型用法中，输入流处理在任何错误时停止；而 <code>feof</code> 和 <span class="t-lc"><a href="c-io-ferror.html">ferror</a></span> 用于区别不同错误条件。</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 <stdlib.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-io.html"><span class="kw883">FILE</span></a><span class="sy2">*</span> fp <span class="sy1">=</span> <a href="c-io-fopen.html"><span class="kw819">fopen</span></a><span class="br0">(</span><span class="st0">"test.txt"</span>, <span class="st0">"r"</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">if</span><span class="br0">(</span><span class="sy3">!</span>fp<span class="br0">)</span> <span class="br0">{</span>
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<a href="c-io-perror.html"><span class="kw878">perror</span></a><span class="br0">(</span><span class="st0">"File opening failed"</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">return</span> <a href="c-program-EXIT_status.html"><span class="kw494">EXIT_FAILURE</span></a><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="kw4">int</span> c<span class="sy4">;</span> <span class="co1">// 注意：int，非char，要求处理EOF</span>
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<span class="kw1">while</span> <span class="br0">(</span><span class="br0">(</span>c <span class="sy1">=</span> <a href="c-io-fgetc.html"><span class="kw827">fgetc</span></a><span class="br0">(</span>fp<span class="br0">)</span><span class="br0">)</span> <span class="sy3">!</span><span class="sy1">=</span> <a href="c-io.html"><span class="kw888">EOF</span></a><span class="br0">)</span> <span class="br0">{</span> <span class="co1">// 标准C I/O读取文件循环</span>
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<a href="c-io-putchar.html"><span class="kw835">putchar</span></a><span class="br0">(</span>c<span class="br0">)</span><span class="sy4">;</span>
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<span class="br0">}</span>
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<span class="kw1">if</span> <span class="br0">(</span><a href="c-io-ferror.html"><span class="kw877">ferror</span></a><span class="br0">(</span>fp<span class="br0">)</span><span class="br0">)</span>
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<a href="c-io-puts.html"><span class="kw836">puts</span></a><span class="br0">(</span><span class="st0">"I/O error when reading"</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">else</span> <span class="kw1">if</span> <span class="br0">(</span>feof<span class="br0">(</span>fp<span class="br0">)</span><span class="br0">)</span>
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<a href="c-io-puts.html"><span class="kw836">puts</span></a><span class="br0">(</span><span class="st0">"End of file reached successfully"</span><span class="br0">)</span><span class="sy4">;</span>
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<a href="c-io-fclose.html"><span class="kw822">fclose</span></a><span class="br0">(</span>fp<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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</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>7.21.10.2 The feof function (p: 339)</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>7.19.10.2 The feof function (p: 305)</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>4.9.10.2 The feof 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-io-clearerr.html"><span class="t-lines"><span>clearerr</span></span></a></div>
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</div>
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</td>
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<td>清除错误<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-io-perror.html"><span class="t-lines"><span>perror</span></span></a></div>
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</div>
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</td>
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<td>显示对应当前错误的字符串到 <span class="t-lc"><a href="c-io.html">stderr</a></span><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-io-ferror.html"><span class="t-lines"><span>ferror</span></span></a></div>
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</div>
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</td>
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<td>检查文件错误<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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</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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