On 24.01.2012 06:32, Sturla Molden wrote: > The use of C long affects all the C and Pyrex source code in mtrand > module, not just mtrand.pyx. All of it is fubar on Win64. randomkit.c handles C long correctly, I think. There are different codes for 32 and 64 bit C long, and buffer sizes are size_t. Sturla