fgetpos, fseek, fseeko, fsetpos, ftell, ftello, rewind -
fgetpos(FILE *stream, fpos_t *pos);
fseek(FILE *stream, long offset, int whence);
fseeko(FILE *stream, off_t offset, int whence);
fsetpos(FILE *stream, const fpos_t *pos);
The fseek() function sets the file position indicator for
pointed to by stream. The new position, measured in bytes,
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 endof-file, respectively.
A successful call to the fseek() function
clears the end-offile
indicator for the stream and undoes any effects of the
function on the same stream.
The fseeko() function is identical to fseek() except that it
off_t as its offset.
The ftell() function obtains the current value of the file
for the stream pointed to by stream.
The ftello() function is identical to ftell() except that
its return value
is of type off_t.
The rewind() function sets the file position indicator for
pointed to by stream to the beginning of the file. It is
(void)fseek(stream, 0L, SEEK_SET)
except that the error indicator for the stream is also
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
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
The rewind() function returns no value. Upon successful
fgetpos(), fseek(), fseeko(), fsetpos() return 0 and ftell()
return the current offset. Otherwise, fseek() and fseeko()
return -1 and
the others return a nonzero value and the global variable
errno is set to
indicate the error.
[EBADF] The stream specified is not a seekable stream.
[EINVAL] The whence argument to fseek() was not
The function fgetpos(), fseek(), fseeko(), fsetpos(),
ftello() may also fail and set errno for any of the errors
the routines fflush(3), fstat(2), lseek(2), and malloc(3).
The fgetpos(), fsetpos(), fseek(), ftell(), and rewind()
to ANSI X3.159-1989 (``ANSI C'') and X/Open Portability
The fseeko() and ftello() functions conform to X/Open Portability Guide
Issue 4 (``XPG4'').
OpenBSD 3.6 February 21, 2000
[ Back ]