/*

* fseek.c - perform an fseek

*/

/* $Header$ */

#include <stdio.h>

#if (SEEK_CUR != 1) || (SEEK_END != 2) || (SEEK_SET != 0)

#error SEEK_* values are wrong

#endif

#include "loc_incl.h"

#include <sys/types.h>

off_t _lseek(int fildes, off_t offset, int whence);

int

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

{

int adjust = 0;

long pos;

stream->_flags &= ~(_IOEOF | _IOERR);

/* Clear both the end of file and error flags */

if (io_testflag(stream, _IOREADING)) {

if (whence == SEEK_CUR

&& stream->_buf

&& !io_testflag(stream,_IONBF))

adjust = stream->_count;

stream->_count = 0;

} else if (io_testflag(stream,_IOWRITING)) {

fflush(stream);

} else /* neither reading nor writing. The buffer must be empty */

/* EMPTY */ ;

pos = _lseek(fileno(stream), offset - adjust, whence);

if (io_testflag(stream, _IOREAD) && io_testflag(stream, _IOWRITE))

stream->_flags &= ~(_IOREADING | _IOWRITING);

stream->_ptr = stream->_buf;

return ((pos == -1) ? -1 : 0);

}