Linux.com

fseek.3

FSEEK

Section: Linux Programmer's Manual (3)
Updated: 1993-11-29
Index Return to Main Contents
 

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 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 3.21 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/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
CONFORMING TO
SEE ALSO
COLOPHON

 

Comments

Subscribe to Comments Feed

Upcoming Linux Foundation Courses

  1. LFD211 Introduction to Linux for Developers
    08 Dec » 09 Dec - Virtual
    Details
  2. LFS220 Linux System Administration
    08 Dec » 11 Dec - Virtual
    Details
  3. LFS520 OpenStack Cloud Architecture and Deployment
    08 Dec » 11 Dec - Virtual
    Details

View All Upcoming Courses

Become an Individual Member
Check out the Friday Funnies

Sign Up For the Linux.com Newsletter


Who we are ?

The Linux Foundation is a non-profit consortium dedicated to the growth of Linux.

More About the foundation...

Frequent Questions

Join / Linux Training / Board