fseek(3) [php man page]

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)

FSEEK(3)						     Linux Programmer's Manual							  FSEEK(3)

NAME

       fgetpos, fseek, fsetpos, ftell, rewind - reposition a stream

SYNOPSIS

       #include <stdio.h>

       int fseek(FILE *stream, long offset, int whence);

       long ftell(FILE *stream);

       void rewind(FILE *stream);

       int fgetpos(FILE *stream, fpos_t *pos);
       int fsetpos(FILE *stream, fpos_t *pos);

DESCRIPTION

       The  fseek()  function  sets  the  file	position  indicator  for the stream pointed to by stream.  The new position, measured in bytes, is
       obtained by adding offset bytes to the position specified by whence.  If whence is set to SEEK_SET, SEEK_CUR, or SEEK_END,  the	offset	is
       relative to the start of the file, the current position indicator, or end-of-file, respectively.  A successful call to the fseek() function
       clears the end-of-file indicator for the stream and undoes any effects of the ungetc(3) function on the same stream.

       The ftell() function obtains the current value of the file position indicator for the stream pointed to by stream.

       The rewind() function sets the file position indicator for the stream pointed to by stream to the beginning of the file.  It is	equivalent
       to:

	      (void) fseek(stream, 0L, SEEK_SET)

       except that the error indicator for the stream is also cleared (see clearerr(3)).

       The fgetpos() and fsetpos() functions are alternate interfaces equivalent to ftell() and fseek() (with whence set to SEEK_SET), setting and
       storing the current value of the file offset into or from the object referenced by pos.	On some non-Unix systems an fpos_t object may be a
       complex object and these routines may be the only way to portably reposition a text stream.

RETURN VALUE

       The  rewind()  function returns no value.  Upon successful completion, fgetpos(), fseek(), fsetpos() return 0, and ftell() returns the cur-
       rent offset.  Otherwise, -1 is returned and errno is set to indicate the error.

ERRORS

       EBADF  The stream specified is not a seekable stream.

       EINVAL The whence argument to fseek() was not SEEK_SET, SEEK_END, or SEEK_CUR.

       The functions fgetpos(), fseek(), fsetpos(), and ftell() may also fail and set errno for any of	the  errors  specified	for  the  routines
       fflush(3), fstat(2), lseek(2), and malloc(3).

CONFORMING TO

       C89, C99.

SEE ALSO

       lseek(2), fseeko(3)

COLOPHON

       This  page is part of release 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

GNU
								    1993-11-29								  FSEEK(3)