gzseek(3) [php man page]

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)

FSEEK(3)								 1								  FSEEK(3)

fseek - Seeks on a file pointer

SYNOPSIS

       int fseek (resource  $handle, int  $offset, [int  $whence = SEEK_SET])

DESCRIPTION

	Sets  the  file position indicator for the file referenced by $handle. The new position, measured in bytes from the beginning of the file,
       is obtained by adding $offset to the position specified by $whence.

	In general, it is allowed to seek past the end-of-file; if data is then written, reads in any unwritten region between the end-of-file and
       the  sought  position  will  yield bytes with value 0. However, certain streams may not support this behavior, especially when they have an
       underlying fixed size storage.

PARAMETERS

	      o $handle
		-A file system pointer resource that is typically created using fopen(3).

	      o $offset
		- The offset.  To move to a position before the end-of-file, you need to pass a negative value	in  $offset  and  set  $whence	to
		SEEK_END.

	      o $whence
		-$whence values are:

		     o SEEK_SET - Set position equal to $offset bytes.

		     o SEEK_CUR - Set position to current location plus $offset.

		     o SEEK_END - Set position to end-of-file plus $offset.

RETURN VALUES

	Upon success, returns 0; otherwise, returns -1.

EXAMPLES

       Example #1

	      fseek(3) example

	      <?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);

	      ?>

NOTES

       Note

	       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, and the result of calling fseek(3) will be undefined.

       Note

	       Not all streams support seeking. For those that do not support seeking, forward seeking from the current position  is  accomplished
	      by reading and discarding data; other forms of seeking will fail.

SEE ALSO

       ftell(3), rewind(3).

PHP Documentation Group 														  FSEEK(3)