RealColor
RealColor Check if an absolute color really exists in the color table
#include <Quickdraw.h> Color Manager
RGBColor *color ; requested color
returns Does this color exist in the color table?
RealColor tells if a requested color is available in the current device's color
table.
color is the RGB requested by the application.
Returns: a Boolean value indicating whether the color actually exists
TRUE (1) color occurs in the current iTabRes.

Notes: The determination of whether or not the color is available rests with the
makeup of the inverse table.