window_tvmx(_c)

	did_it.i4.v = window_tvmx(window_id.i2.r, row.i4.r, column.i4.r,
				  text.sa.r, num_chars.i4.r)

	did_it.i4.v = window_tvmx_c(window_id.i2.v, row.i4.v, column.i4.v,
				    text.sa.r, num_chars.i4.v)

	This routine will display text in the window indicated by "window_id"
	if "num_chars" is greater than or equal to zero.  It will read in
	text if "num_chars" is less than zero.  Character attributes
	(colors and blink) are specified for each character individually.
	This routine will return a value of TRUE if any characters are
	actually read or written.  Otherwise, it will return a value of FALSE.
	Characters can only be read from the visible portion of the window
	with this routine.

	window_id	window ID (use WMNGR_BACKGROUND for background window)
	row, column	starting window coordinate location
			(1,1 is the location inside the upper left hand
			 corner of a bordered window or 0,0 for a borderless
			 window)
	text		user buffer of ASCII data and character attributes
			to be read or written, one character per word.
			The low byte of each word contains an ASCII
			character and the high byte contains the display
			attributes for the character.  The ITVATT function
			is available to build the character attribute.
			Character attributes are described below.
	num_chars	number of ASCII characters to be read from or
			written to the screen.  If the value of "num_chars"
			is negative, a read operation is performed.
			(Note : A null string will be returned if the window
			is occluded.)  If "num_chars" is positive, a write
			operation is performed.  If "num_chars" = 0, the
			length of the string pointed to by "text" is
			determined and used.

	This function returns status values as follows:

	TRUE			window I/O actually done
	FALSE			no window I/O done

	This function requires the following include files:

	cnsparam_h, cns_data_structs_h, cbslib_h

	Related functions:

	window_tvm(_c), btvm(_c), btvmx(_c), window_draw_char_c,
	window_entry_to_row_c, window_display_value(_c),
	window_write_xchar_line_c, window_write_scroll_xchar_c,
	window_write_scroll_c, window_center_text(_c), window_vertical_text(_c),
	window_justify_text_c, window_write_string_c, window_up_case_c,
	window_down_case_c, window_text_fill(_c), window_read_color_text_c,
	window_input_value(_c), window_construct(_c), intro_tv_windows

	C/C++ usage:

	short	window_id;
	int	did_it;
	int	row = 1;
	int	column = 1;
	int	num_chars = NUM_CHARS;
	static const XCHAR	text[NUM_CHARS] =
	{{'U', RED}, {'S', WHITE}, {'A', BLUE}};

	did_it = window_tvmx_c(window_id,row,column,text,num_chars);