status.i4.v = wn_erase([erase_color.i4.r] [,erase_region.i4.r])

	status.i4.v = wn_erase_c([erase_color.i4.v] [,erase_region.i4.v])

	This routine erases the active graphic window.

	[erase_color]	color plane(s) to be erased (different plane
			values can be ORed together) (default is WN_ERASE_ALL)
			(WN_ERASE_ALL -> erase all planes,
			 WN_ERASE_BLUE -> erase blue plane only,
			 WN_ERASE_GREEN -> erase green plane only,
			 WN_ERASE_RED -> erase red plane only,
			 WN_ERASE_BLINK -> erase blink plane only)
	[erase_region]	region to erase
			(WN_ERASE_ENTIRE_WINDOW -> erase entire window
						   including any external
						   text (default),
			 WN_ERASE_INTERIOR_ONLY -> erase interior of window
			 WN_ERASE_PRESERVE_GRID -> erase interior of window
						   only and preserve any grids)

	This function returns ACNET status values as follows:

	OK			success
	CBS_NOSETUP		an active window has not been established
	CBS_INVARG		invalid erase color

	This function requires the following include files:

	cnsparam_h, cbslib_h, acnet_errors_h

	Related functions:

	wn_erase_screen_c, wn_delete_c, wn_delete_all_c, wn_flush,
	wn_redraw_grid_c, intro_graphics_windows

	C/C++ usage:

	int	status;
	int	erase_color = WN_ERASE_ALL;
	int	erase_region = WN_ERASE_ENTIRE_WINDOW;

	status = wn_erase_c(erase_color,erase_region);