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119 lines
5.3 KiB
HTML
119 lines
5.3 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>判断给定文件名是否可读</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.is-readable" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">is_readable</h1>
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<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">is_readable</span> — <span class="dc-title">判断给定文件名是否可读</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.is-readable-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>is_readable</strong></span>
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( <span class="methodparam"><span class="type">string</span> <code class="parameter">$filename</code></span>
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) : <span class="type">bool</span></div>
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<p class="para rdfs-comment">
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判断给定文件名是否存在并且可读。
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.is-readable-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">filename</code></dt>
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<dd>
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<p class="para">
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文件的路径。
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</p>
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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.is-readable-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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如果由 <code class="parameter">filename</code>
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指定的文件或目录存在并且可读则返回 <strong><code>TRUE</code></strong>，否则返回 <strong><code>FALSE</code></strong>。
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</p>
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</div>
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<div class="refsect1 examples" id="refsect1-function.is-readable-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-2816">
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<p><strong>Example #1 <span class="function"><strong>is_readable()</strong></span> 例子</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 />$filename </span><span style="color: #007700">= </span><span style="color: #DD0000">'test.txt'</span><span style="color: #007700">;<br />if (</span><span style="color: #0000BB">is_readable</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">'The file is readable'</span><span style="color: #007700">;<br />} else {<br /> echo </span><span style="color: #DD0000">'The file is not readable'</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 errors" id="refsect1-function.is-readable-errors">
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<h3 class="title">错误／异常</h3>
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<p class="para">
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失败时抛出<strong><code>E_WARNING</code></strong>警告。
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</p>
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</div>
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<div class="refsect1 notes" id="refsect1-function.is-readable-notes">
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<h3 class="title">注释</h3>
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<p class="para">
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记住 PHP 也许只能以运行 webserver 的用户名（通常为
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'nobody'）来访问文件。不计入安全模式的限制。
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Safe mode
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limitations are not taken into account before PHP 5.1.5.
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</p>
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<blockquote class="note"><p><strong class="note">Note</strong>: <span class="simpara">此函数的结果会被缓存。参见
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<span class="function"><a href="clearstatcache.html" class="function">clearstatcache()</a></span> 以获得更多细节。</span></p></blockquote>
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<div class="tip"><strong class="tip">Tip</strong><p class="simpara">自 PHP 5.0.0 起, 此函数也用于<em class="emphasis">某些</em>
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URL 包装器。请参见 <a href="wrappers.html" class="xref">支持的协议和封装协议</a>以获得支持 <span class="function"><a href="stat.html" class="function">stat()</a></span> 系列函数功能的包装器列表。</p></div>
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<blockquote class="note"><p><strong class="note">Note</strong>:
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<p class="para">
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The check is done using the real UID/GID instead of the effective one.
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</p>
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</p></blockquote>
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<p class="para">
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对于目录这个函数可能会返回 <strong><code>TRUE</code></strong>。请使用 <span class="function"><a href="is_dir.html" class="function">is_dir()</a></span> 来区分文件和目录。
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</p>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.is-readable-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="is_writable.html" class="function" rel="rdfs-seeAlso">is_writable()</a> - 判断给定的文件名是否可写</span></li>
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<li class="member"><span class="function"><a href="file_exists.html" class="function" rel="rdfs-seeAlso">file_exists()</a> - 检查文件或目录是否存在</span></li>
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<li class="member"><span class="function"><a href="fgets.html" class="function" rel="rdfs-seeAlso">fgets()</a> - 从文件指针中读取一行</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> |