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<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.11 $ -->
<!-- splitted from ./en/functions/filesystem.xml, last change in rev 1.2 -->
<refentry id="function.fseek">
<refnamediv>
<refname>fseek</refname>
<refpurpose>Seeks on a file pointer</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<methodsynopsis>
<type>int</type><methodname>fseek</methodname>
<methodparam><type>resource</type><parameter>handle</parameter></methodparam>
<methodparam><type>int</type><parameter>offset</parameter></methodparam>
<methodparam choice="opt"><type>int</type><parameter>whence</parameter></methodparam>
</methodsynopsis>
<para>
Sets the file position indicator for the file referenced by
<parameter>handle</parameter>. The new position, measured in bytes
from the beginning of the file, is obtained by adding
<parameter>offset</parameter> to the position specified by
<parameter>whence</parameter>, whose values are defined as
follows:
<simplelist>
<member><constant>SEEK_SET</constant> - Set position equal to <parameter>offset</parameter> bytes.</member>
<member><constant>SEEK_CUR</constant> - Set position to current location plus <parameter>offset</parameter>.</member>
<member><constant>SEEK_END</constant> - Set position to end-of-file plus <parameter>offset</parameter>.
(To move to a position before the end-of-file, you need to pass a negative
value in <parameter>offset</parameter>.)</member>
</simplelist>
</para>
<para>
If <parameter>whence</parameter> is not specified, it is assumed to be
<constant>SEEK_SET</constant>.
</para>
<para>
Upon success, returns 0; otherwise, returns -1. Note that seeking
past EOF is not considered an error.
</para>
<para>
<example>
<title><function>fseek</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
$fp = fopen('somefile.txt', 'r');
// read some data
$data = fgets($fp, 4096);
// move back to the beginning of the file
// same as rewind($fp);
fseek($fp, 0);
?>
]]>
</programlisting>
</example>
</para>
<para>
May not be used on file pointers returned by
<function>fopen</function> if they use the "http://" or "ftp://"
formats. <function>fseek</function> gives also undefined results for
append-only streams (opened with "a" flag).
</para>
<note>
<para>
The <parameter>whence</parameter> argument was added after PHP 4.0.0.
</para>
</note>
<note>
<para>
If you have opened the file in append ("a" or "a+") mode, any data you write
to the file will always be appended, regardless of the file position.
</para>
</note>
<para>
See also <function>ftell</function> and
<function>rewind</function>.
</para>
</refsect1>
</refentry>
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