Comment by jezze

I think it would have been better if they had designed it so that the error message from the kernel came in a seperate register. That would mean you didnt have to use signed int for the return value. The issue is that one register now is sort of disambigious. It either returns the thing you want or the error but these are seperate types. If you had them in seperate registers you would have the natural type of the thing you are interested in without having to convert it. This would however force you to first check the value in the error register before using the value in the return register but that makes more sense to me than the opposite.