is-readable.xml

<?xml version="1.0" encoding="utf-8"?>
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<refentry xml:id="function.is-readable" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>is_readable</refname>
  <refpurpose>判断给定文件名是否可读</refpurpose>
 </refnamediv>
 
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type><methodname>is_readable</methodname>
   <methodparam><type>string</type><parameter>filename</parameter></methodparam>
  </methodsynopsis>
  <para>
   判断给定文件名是否存在并且可读。
  </para>
 </refsect1>
 
 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>filename</parameter></term>
     <listitem>
      <para>
       文件的路径。
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   如果由 <parameter>filename</parameter>
   指定的文件或目录存在并且可读则返回 &true;，否则返回 &false;。
  </para>
 </refsect1>

 <refsect1 role="errors">
  &reftitle.errors;
  &fs.emits.warning.on.failure;
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>is_readable</function> 例子</title>
    <programlisting role="php">
<![CDATA[
<?php
$filename = 'test.txt';
if (is_readable($filename)) {
    echo 'The file is readable';
} else {
    echo 'The file is not readable';
}
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <para>
   记住 PHP 也许只能以运行 webserver 的用户名（通常为
   'nobody'）来访问文件。不计入安全模式的限制。
  </para>
  &note.clearstatcache;
  &tip.fopen-wrapper.stat;
  <note>
   <para>
    The check is done using the real UID/GID instead of the effective one.
   </para>
  </note>
  <para>
   对于目录这个函数可能会返回 &true;。请使用 <function>is_dir</function> 来区分文件和目录。
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>is_writable</function></member>
    <member><function>file_exists</function></member>
    <member><function>fgets</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>

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