window_center_text(_c)

	did_it.i4.v = window_center_text(window_id.i2.r, row.i4.r, text.i1a.r,
					 num_chars.i4.r, color.i4.r)

	did_it.i4.v = window_center_text_c(window_id.i2.v, row.i4.v, text.i1a.r,
					   num_chars.i4.v, color.i4.v)

	This routine will display text centered in the window indicated
	by "window_id".  This routine will return a value of TRUE if any
	characters are actually read or written.  Otherwise, it will
	return a value of FALSE.

	window_id	window ID (use WMNGR_BACKGROUND for background window)
	row		window row
	text		user buffer of ASCII data to be read or written,
			one character per byte
	num_chars	number of ASCII characters to be written to the
			screen  (If "num_chars" is 0, the length of the
			string pointed to by "text" is determined and used.)
			(Note : Only exposed portions of a window will be
			 written to.)
	color		display color  (If a background color other than
			black is desired, a compound color value can be
			constructed using tv_colors or TV_COLORS_WBLINK.)
			(constants are in 'cnsparam')

	This function returns status values as follows:

	CBS_MEMFAIL		dynamic memory allocation failure
	CBS_NO_WINDOW		requested window does not exist
	TRUE			some characters were written to the window
	FALSE			no characters were written to the window

	This function requires the following include files:

	cnsparam_h, cbslib_h, acnet_errors_h

	Related functions:

	window_tvm(_c), window_tvmx(_c), window_write_string_c, tv_colors,
	TV_COLORS_WBLINK, intro_tv_windows

	C/C++ usage:

	static const char	text[] = "Text";
	short	window_id;
	int	did_it;
	int	row = 1;
	int	num_chars = 0;
	int	color = WHITE;

	did_it = window_center_text_c(window_id,row,text,num_chars,color);