| NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | SEE ALSO | COLOPHON | The Linux Programming Interface |
FSEEK(3) Linux Programmer's Manual FSEEK(3)
fgetpos, fseek, fsetpos, ftell, rewind - reposition a stream
#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);
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.
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.
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).
C89, C99.
lseek(2), fseeko(3)
This page is part of release 3.32 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)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface