Hum, I prefer#117032 approach with one member type per C type.

Thanks@StanFromIreland.

What do you think about using the lower byte for allPyLong_AsNativeBytes flags (not just signedness), as@zooba proposed?

Perhaps Py_ASNATIVEBYTES_UNSIGNED_BUFFER can be used without Py_ASNATIVEBYTES_REJECT_NEGATIVE (but not opposite). All other flags do not make sense here. Endianess is always native, there is no reason to not support__index__.

Question: how to combine this withPy_INTEGER()?

Perhaps Py_ASNATIVEBYTES_UNSIGNED_BUFFER can be used without Py_ASNATIVEBYTES_REJECT_NEGATIVE (but not opposite).

If you use UNSIGNED_BUFFER without REJECT_NEGATIVE, then you can get data in the most significant bit for a large positive int rather than being guaranteed a sign bit. It's like a normal C cast.

Without UNSIGNED_BUFFER but with REJECT_NEGATIVE, you're guaranteed that the top bit is going to be 0, because it must be the sign bit and you'll never have a negative value, so you have 1 fewer bits of data.

If a normal C cast is not appropriate here (and I don't think it is), then for unsigned types you'll want both flags and for signed types you'll want neither.