I use X11 gtk gdk on linux C++

I can get a keyval from a keycode and shiftstate using gdk_keymap_translate_keyboard_state().
But I cannot see how this works for deadkeys because I need to process 2 Keys in a row. E.g. of a deadkey + character I want to obtain the Keyval of the combined character e.g.

( 94(^) + A(65) –> Â(194)

Is there a way to get the processed deadkey without using an event? I am looking for something like :

Combined_Character = gdk_someFunction(GDKkeymap, deadkey, other_key, shiftstate_dk, shiftstate_key);