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168 lines
8.2 KiB
HTML
168 lines
8.2 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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<meta http-equiv="content-type" content="text/html; charset=UTF-8">
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<title>从文件指针中读取一行</title>
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</head>
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<body class="docs"><div id="layout">
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<div id="layout-content"><div id="function.fgets" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">fgets</h1>
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<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">fgets</span> — <span class="dc-title">从文件指针中读取一行</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.fgets-description">
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<h3 class="title">说明</h3>
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<div class="methodsynopsis dc-description">
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<span class="methodname"><strong>fgets</strong></span>
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( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$handle</code></span>
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[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$length</code></span>
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] ) : <span class="type">string</span></div>
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<p class="para rdfs-comment">
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从文件指针中读取一行。
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.fgets-parameters">
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<h3 class="title">参数</h3>
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<p class="para">
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<dl>
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<dt>
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<code class="parameter">handle</code></dt>
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<dd>
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<p class="para">文件指针必须是有效的，必须指向由
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<span class="function"><a href="fopen.html" class="function">fopen()</a></span> 或 <span class="function"><a href="fsockopen.html" class="function">fsockopen()</a></span> 成功打开的文件(并还未由 <span class="function"><a href="fclose.html" class="function">fclose()</a></span> 关闭)。</p>
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</dd>
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<dt>
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<code class="parameter">length</code></dt>
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<dd>
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<p class="para">
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从 <code class="parameter">handle</code>
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指向的文件中读取一行并返回长度最多为 <code class="parameter">length</code> - 1
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字节的字符串。碰到换行符（包括在返回值中）、EOF 或者已经读取了 length - 1
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字节后停止（看先碰到那一种情况）。如果没有指定
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<code class="parameter">length</code>，则默认为 1K，或者说 1024 字节。
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</p>
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<blockquote class="note"><p><strong class="note">Note</strong>:
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<p class="para">
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从 PHP 4.3 开始，忽略掉
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length 则行的长度被假定为 1024，将继续从流中读取数据直到行结束。如果文件中的大多数行都大于
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8KB，则在脚本中指定最大行的长度在利用资源上更为有效。
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</p>
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</p></blockquote>
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</dd>
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</dl>
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</p>
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</div>
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<div class="refsect1 returnvalues" id="refsect1-function.fgets-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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从指针 <code class="parameter">handle</code> 指向的文件中读取了 <code class="parameter">length</code> - 1 字节后返回字符串。
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如果文件指针中没有更多的数据了则返回 <strong><code>FALSE</code></strong>。
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</p>
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<p class="para">
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错误发生时返回 <strong><code>FALSE</code></strong>。
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</p>
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</div>
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<div class="refsect1 changelog" id="refsect1-function.fgets-changelog">
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<h3 class="title">更新日志</h3>
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<p class="para">
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<table class="doctable informaltable">
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<thead>
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<tr>
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<th>版本</th>
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<th>说明</th>
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</tr>
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</thead>
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<tbody class="tbody">
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<tr>
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<td>4.3.0</td>
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<td>
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<span class="function"><strong>fgets()</strong></span> 开始二进制安全
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</td>
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</tr>
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<tr>
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<td>4.2.0</td>
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<td>
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<code class="parameter">length</code> 参数成为可选。
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</td>
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</tr>
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</tbody>
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</table>
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</p>
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</div>
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<div class="refsect1 examples" id="refsect1-function.fgets-examples">
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<h3 class="title">范例</h3>
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<p class="para">
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<div class="example" id="example-2775">
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<p><strong>Example #1 逐行读取文件</strong></p>
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<span style="color: #0000BB"><?php<br />$handle </span><span style="color: #007700">= @</span><span style="color: #0000BB">fopen</span><span style="color: #007700">(</span><span style="color: #DD0000">"/tmp/inputfile.txt"</span><span style="color: #007700">, </span><span style="color: #DD0000">"r"</span><span style="color: #007700">);<br />if (</span><span style="color: #0000BB">$handle</span><span style="color: #007700">) {<br /> while ((</span><span style="color: #0000BB">$buffer </span><span style="color: #007700">= </span><span style="color: #0000BB">fgets</span><span style="color: #007700">(</span><span style="color: #0000BB">$handle</span><span style="color: #007700">, </span><span style="color: #0000BB">4096</span><span style="color: #007700">)) !== </span><span style="color: #0000BB">false</span><span style="color: #007700">) {<br /> echo </span><span style="color: #0000BB">$buffer</span><span style="color: #007700">;<br /> }<br /> if (!</span><span style="color: #0000BB">feof</span><span style="color: #007700">(</span><span style="color: #0000BB">$handle</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">"Error: unexpected fgets() fail\n"</span><span style="color: #007700">;<br /> }<br /> </span><span style="color: #0000BB">fclose</span><span style="color: #007700">(</span><span style="color: #0000BB">$handle</span><span style="color: #007700">);<br />}<br /></span><span style="color: #0000BB">?></span>
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</span>
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</pre></div>
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</div>
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</div>
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</p>
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</div>
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<div class="refsect1 notes" id="refsect1-function.fgets-notes">
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<h3 class="title">注释</h3>
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<blockquote class="note"><p><strong class="note">Note</strong>: <span class="simpara">在读取在 Macintosh 电脑中或由其创建的文件时， 如果 PHP
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不能正确的识别行结束符，启用运行时配置可选项 <a href="filesystem.configuration.html#ini.auto-detect-line-endings" class="link">auto_detect_line_endings</a>
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也许可以解决此问题。</span></p></blockquote>
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<blockquote class="note"><p><strong class="note">Note</strong>:
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<p class="para">
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习惯了 C 语言中 <span class="function"><strong>fgets()</strong></span> 语法的人应该注意到 <em>EOF</em>
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是怎样被返回的。
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</p>
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</p></blockquote>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.fgets-seealso">
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<h3 class="title">参见</h3>
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<p class="para">
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<ul class="simplelist">
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<li class="member"><span class="function"><a href="fgetss.html" class="function" rel="rdfs-seeAlso">fgetss()</a> - 从文件指针中读取一行并过滤掉 HTML 标记</span></li>
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<li class="member"><span class="function"><a href="fread.html" class="function" rel="rdfs-seeAlso">fread()</a> - 读取文件（可安全用于二进制文件）</span></li>
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<li class="member"><span class="function"><a href="fgetc.html" class="function" rel="rdfs-seeAlso">fgetc()</a> - 从文件指针中读取字符</span></li>
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<li class="member"><span class="function"><a href="stream_get_line.html" class="function" rel="rdfs-seeAlso">stream_get_line()</a> - 从资源流里读取一行直到给定的定界符</span></li>
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<li class="member"><span class="function"><a href="fopen.html" class="function" rel="rdfs-seeAlso">fopen()</a> - 打开文件或者 URL</span></li>
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<li class="member"><span class="function"><a href="popen.html" class="function" rel="rdfs-seeAlso">popen()</a> - 打开进程文件指针</span></li>
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<li class="member"><span class="function"><a href="fsockopen.html" class="function" rel="rdfs-seeAlso">fsockopen()</a> - 打开一个网络连接或者一个Unix套接字连接</span></li>
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<li class="member"><span class="function"><a href="stream_set_timeout.html" class="function" rel="rdfs-seeAlso">stream_set_timeout()</a> - Set timeout period on a stream</span></li>
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</ul>
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</p>
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</div>
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</div></div></div></body></html> |