Curt Hagenlocher skrev:

Does that not happen on non-Windows platforms? 2**31 can't be represented as a 32-bit signed integer, so it's automatically promoted to a long.

Yes you are right. I've now traced down the problem to an integer overflow in NumPy. It seems to have this Pyrex code: cdef long lo, hi, diff [...] diff = hi - lo - 1 :-D Sturla