// start of Update ()
		keyboard = SDL_GetKeyboardState (&numKeys);
		if (numKeys > lastNumKeys)
		{
			if (lastKeyboard) free ((void *) lastKeyboard);
			lastKeyboard = (Uint8 *) malloc (numKeys * sizeof (Uint8));
		}

// end of Update ()
		memcpy ((void *) lastKeyboard, (void *) keyboard, numKeys * sizeof (Uint8));
		lastNumKeys = numKeys;