As one can see from Xcode's GUI for editing .xcdatamodel files, Core Data supports signed 16, 32, and 64 bit integers for attributes types. In turn, mogenerator creates accessors that return scalars for these attributes. The types returned are: short, int, and long long. These are correct for the current Mac OS ABI.
However, it would be even more correct to return int16_t, int32_t, and int64_t instead.
We once tried to make this change, but it was tricker than I thought because IIRC it assumed that there are NSNumber methods named Value, like 'shortValue' but there is no int16_tValue method.
Yup, that's where I got stuck too. I'm a fan of intXX_t, but decided it wasn't worth the effort (yet).
Has anything changed in the last 2 years that would make this achievable at this point?
I don't think so, sorry.