sub chkfmt {
  unless ( $DISCPCNT and $DISCDAYSDUE and $NETDAYSDUE and 
          !( $DISCDUEDATE or $NETDUEDATE or $TERMSDISCAMT )
         ) {
	print TSERROR "First condition failed\n";
  }

  unless ( $DISCDUEDATE && $TERMSDISCAMT &&
          ! ( $DISCPCNT || $DISCDAYSDUE || $NETDUEDATE ||
	      $NETDAYSDUE ) ) {
	print TSERROR "Second condition failed\n";
  }

  unless ( $DISCPCNT && $DISCDUEDATE &&
	  ! ( $DISCDAYSDUE || $NETDUEDATE || $NETDAYSDUE ||
	      $TERMSDISCAMT ) 
          ) {
	print TSERROR "Third condition failed"
  }