status.i4.v = window_register_function_c(window_id.i2.v, type.i4.v,

	This routine will register a function to be executed when a
	particular type of event occurs in the indicated window.

	window_id	window ID
	type		type of function
			(WMNGR_DESTRUCTOR_FUNC -> called when window is deleted,
			 WMNGR_SCROLL_FUNC -> called when window is scrolled
					      either horizontally or vertically,
			 WMNGR_RESIZE_FUNC -> called when window is resized,
			 WMNGR_MOVE_FUNC -> called when the window is moved)
			 WMNGR_EXPOSE_FUNC -> called when the window is popped
					      to the top,
			 WMNGR_OCCLUDE_FUNC -> called when the window is
	callb_function	address of function to be called as follows:
			callback(wid.i2.v, callb_data.g.v, op_data.s.r)
			("op_data" is a structure which is dependent on the
			 operation generating the callback having the
			 following types:
			 WINDOW_SCROLL_DATA -> horizontal or vertical
					       scroll operation,
			 WINDOW_RESIZE_DATA -> resize operation,
			 WINDOW_MOVE_DATA -> move operation,
			 WINDOW_EXPOSE_DATA -> window popped to the top,
			 WINDOW_OCCLUDE_DATA -> window occluded)
	[callb_data]	pointer to user-supplied data to be passed to
			callback function (default is NULL)

	This function returns status values as follows:

	OK			success
	CBS_INVARG		invalid window ID or function type was specified
	CBS_NO_WINDOW		requested window does not exist
	CBS_MEMFAIL		dynamic memory allocation failure

	This function requires the following include files:

	cns_data_structs_h, cbslib_h, acnet_errors_h

	Related functions:

	window_unregister_function_c, window_delete(_c), window_scroll(_c),
	window_move, window_resize, window_callback_init, window_callback_term,
	window_add_callback_c, window_remove_callback_c, intro_tv_windows

	C/C++ usage:

	short	window_id;
	int	status;
	void	callb_function(short window_id, void *callback_data);
	void	*callb_data = (void *) NULL;

	status = window_register_function_c(window_id,type,