gzseek

gzseek — Seek on a gz-file pointer
Description
int gzseek ( resource $zp , int $offset [, int $whence = SEEK_SET ] )

Sets the file position indicator for the given file pointer to the given offset byte into the file stream. Equivalent to calling (in C) gzseek(zp, offset, SEEK_SET).

If the file is opened for reading, this function is emulated but can be extremely slow. If the file is opened for writing, only forward seeks are supported; gzseek() then compresses a sequence of zeroes up to the new starting position.
Parameters

zp

The gz-file pointer. It must be valid, and must point to a file successfully opened by gzopen().
offset

The seeked offset.
whence

whence values are:

* SEEK_SET - Set position equal to offset bytes.
* SEEK_CUR - Set position to current location plus offset.

If whence is not specified, it is assumed to be SEEK_SET.

Return Values

Upon success, returns 0; otherwise, returns -1. Note that seeking past EOF is not considered an error.
Examples

Example #1 gzseek() example
<?php
$gz = gzopen('somefile.gz', 'r');
gzseek($gz,2);
echo gzgetc($gz);
gzclose($gz);
?>