RayLivingston:
Your code, exactly as you posted it does NOT compile here, It gives the exact same errors I get with mine - va_list is undefined.Regards,
Ray L.
It compiles fine for me when targeting the Due. In fact, I've been using these variadic functions in GEVCU for years. It has always compiled perfectly well. You have to have something really messed up with your Arduino installation because it works fine for everyone else. I know that's probably not what you want to hear but it really does compile fine so the problem is on your end.