This function allows for changing the underline attribute to an arbitrary fg/bg color combination. It is useful for slight aesthetic improvement to legacy text-mode programs which use underline, since underline has a rather old-fashioned look.
TAB(-10,AG_ATTRSUB);"1,2,";FG'R;",";FG'G;",";FG'B;","; BG'R;",";BG'G;",";BG'B;chr(127);
where FG'R, FG'G, FG'B are the RGB values (0-255) for the foreground color, and BG'R, BG'G, BG'B are the RGB values (0-255) for the background color.
