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, respec-
       tively.  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 current 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 3.25 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)