window_last_scroll

	num_lines.i4.v = window_last_scroll()

	Returns the number of lines actually scrolled by the last window
	scroll command.  A negative value indicates a scroll up, and a
	positive value indicates a scroll down.

	This function returns status values as follows:

	number of lines scrolled

	This function requires the following include files:

	cbslib_h

	Related functions:

	window_query_scroll, window_total_lines_c, window_scroll(_c),
	window_scroll_page_c, window_scroll_to_bottom_c, window_scroll_to_top_c,
	window_last_horizontal_scroll, window_hscroll_c, window_hscroll_page_c, 
	window_scroll_to_left_c, window_scroll_to_right_c, intro_tv_windows

	C/C++ usage:

	int	num_lines;

	num_lines = window_last_scroll();