text: /*
   * fseek.c - perform an fseek
   */
  /* $Header: /cvsup/minix/src/lib/stdio/fseek.c,v 1.1.1.1 2005/04/21 14:56:35 beng Exp $ */
  
  #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);
  }
  