php man page for gzseek

GZSEEK(3)								 1								 GZSEEK(3)

gzseek - Seek on a gz-file pointer

SYNOPSIS
       int gzseek (resource  $zp, int  $offset, [int  $whence = SEEK_SET])

DESCRIPTION
	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(3) then compresses a sequence of zeroes up to the new starting position.

PARAMETERS
	      o $zp
		- The gz-file pointer. It must be valid, and must point to a file successfully opened by gzopen(3).

	      o $offset
		- The seeked offset.

	      o $whence
		-$whence values are:

		     o SEEK_SET - Set position equal to $offset bytes.

		     o 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(3) example

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

SEE ALSO
       gztell(3), gzrewind(3).

PHP Documentation Group 														 GZSEEK(3)