debian man page for fseek

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 3.44 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)