GeezerVison

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

Thanks @StanFromIreland.

What do you think about using the lower byte for all PyLong_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 with Py_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.

This PR is stale because it has been open for 30 days with no activity.