rxvt_term *		T_TERM
timer *			T_TIMER
iow *			T_IOW
overlay *		T_OVERLAY

INPUT
T_TERM
	$var = SvTERM ($arg);
T_TIMER
	$var = SvTIMER ($arg);
T_IOW
	$var = SvIOW ($arg);
T_OVERLAY
	$var = SvOVERLAY ($arg);

OUTPUT
T_TERM
	$arg = newSVterm ($var);
T_TIMER
	$arg = newSVtimer ($var);
T_IOW
	$arg = newSViow ($var);