uTools-Manuals/docs/php/is_writable.html
2019-04-28 19:00:34 +08:00

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<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>判断给定的文件名是否可写</title>
</head>
<body class="docs"><div id="layout">
<div id="layout-content"><div id="function.is-writable" class="refentry">
<div class="refnamediv">
<h1 class="refname">is_writable</h1>
<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">is_writable</span> &mdash; <span class="dc-title">判断给定的文件名是否可写</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.is-writable-description">
<h3 class="title">说明</h3>
<div class="methodsynopsis dc-description">
<span class="methodname"><strong>is_writable</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$filename</code></span>
) : <span class="type">bool</span></div>
<p class="para rdfs-comment">
如果文件存在并且可写则返回 <strong><code>TRUE</code></strong><code class="parameter">filename</code>
参数可以是一个允许进行是否可写检查的目录名。
</p>
<p class="para">
记住 PHP 也许只能以运行 webserver 的用户名(通常为
&#039;nobody&#039;)来访问文件。不计入安全模式的限制。
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.is-writable-parameters">
<h3 class="title">参数</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">filename</code></dt>
<dd>
<p class="para">
要检查的文件名称。
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.is-writable-returnvalues">
<h3 class="title">返回值</h3>
<p class="para">如果文件 <code class="parameter">filename</code> 存在并且可写则返回 <strong><code>TRUE</code></strong>
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.is-writable-examples">
<h3 class="title">范例</h3>
<p class="para">
<div class="example" id="example-2818">
<p><strong>Example #1 <span class="function"><strong>is_writable()</strong></span> 例子</strong></p>
<div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$filename&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'test.txt'</span><span style="color: #007700">;<br />if&nbsp;(</span><span style="color: #0000BB">is_writable</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">))&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">'The&nbsp;file&nbsp;is&nbsp;writable'</span><span style="color: #007700">;<br />}&nbsp;else&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">'The&nbsp;file&nbsp;is&nbsp;not&nbsp;writable'</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 errors" id="refsect1-function.is-writable-errors">
<h3 class="title">错误/异常</h3>
<p class="para">
失败时抛出<strong><code>E_WARNING</code></strong>警告。
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.is-writable-notes">
<h3 class="title">注释</h3>
<blockquote class="note"><p><strong class="note">Note</strong>: <span class="simpara">此函数的结果会被缓存。参见
<span class="function"><a href="clearstatcache.html" class="function">clearstatcache()</a></span> 以获得更多细节。</span></p></blockquote>
<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>
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>
</div>
<div class="refsect1 seealso" id="refsect1-function.is-writable-seealso">
<h3 class="title">参见</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="is_readable.html" class="function" rel="rdfs-seeAlso">is_readable()</a> - 判断给定文件名是否可读</span></li>
<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>
<li class="member"><span class="function"><a href="fwrite.html" class="function" rel="rdfs-seeAlso">fwrite()</a> - 写入文件(可安全用于二进制文件)</span></li>
</ul>
</p>
</div>
</div></div></div></body></html>