status.i4.v = window_key_echo_c(key_echo.i4.v)

	This routine determines which characters typed in by the user
	will be echoed to the screen.  It also returns the the previous

	key_echo	key echo request value (passing a value of
			CLIB_DEFAULT allows the caller to simply read
			the present value)
			(KEY_ECHO_ALL -> allow echoing of all characters
					 (default at program startup),
			 KEY_ECHO_NONE -> suppress the echoing of all
					  characters except cursor
					  positioning ones,
			 KEY_ECHO_NOKP -> suppress the echoing of key pad
			 KEY_ECHO_NOTAB -> suppress the echoing of tab
			 KEY_ECHO_NOCTRL -> suppress the echoing of control
			 CLIB_DEFAULT_ARG -> return the current echo value)

	This function returns status values as follows:

	CBS_MEMFAIL		dynamic memory allocation failure
	CBS_INVARG		invalid echo value passed
	otherwise		previous key echo value

	This function requires the following include files:

	cbslib_h, tvlib_h, acnet_errors_h

	Related functions:

	window_key_case_c, window_key_color_c, intro_tv_windows

	C/C++ usage:

	int	status;
	int	key_echo = KEY_ECHO_ALL;

	status = window_key_echo_c(key_echo);