MirBSD manpage: fgetpos(3), fseek(3), fseeko(3), fsetpos(3), ftell(3), ftello(3), rewind(3)

FSEEK(3)                   BSD Programmer's Manual                    FSEEK(3)

NAME

     fgetpos, fseek, fseeko, fsetpos, ftell, ftello, rewind - reposition a
     stream

SYNOPSIS

     #include <stdio.h>

     int
     fgetpos(FILE *stream, fpos_t *pos);

     int
     fseek(FILE *stream, long offset, int whence);

     int
     fseeko(FILE *stream, off_t offset, int whence);

     int
     fsetpos(FILE *stream, const fpos_t *pos);

     long
     ftell(FILE *stream);

     off_t
     ftello(FILE *stream);

     void
     rewind(FILE *stream);

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, respective-
     ly. A successful call to the fseek() function clears the end-of-file in-
     dicator for the stream and undoes any effects of the ungetc(3) function
     on the same stream.

     The fseeko() function is identical to fseek() except that it takes an
     off_t as its offset.

     The ftell() function obtains the current value of the file position indi-
     cator 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 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 VALUES

     The rewind() function returns no value. Upon successful completion, fget-
     pos(), fseek(), fseeko(), fsetpos() return 0 and ftell() and ftello() re-
     turn the current offset. Otherwise, fseek() and fseeko() return -1 and
     the others return a non-zero value and the global variable 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(), fseeko(), fsetpos(), ftell(), and ftel-
     lo() may also fail and set errno for any of the errors specified for the
     routines fflush(3), fstat(2), lseek(2), and malloc(3).

SEE ALSO

     lseek(2)

STANDARDS

     The fgetpos(), fsetpos(), fseek(), ftell(), and rewind() functions con-
     form to ANSI X3.159-1989 ("ANSI C89") and X/Open Portability Guide Issue
     4 ("XPG4").

     The fseeko() and ftello() functions conform to X/Open Portability Guide
     Issue 4 ("XPG4").

MirBSD #10-current            February 21, 2000                              1