[QUOTE=rogue;424451]I'm not familiar with that feature of gwnum.

I have good news and bad news. The good news is that I have been able to reproduce the problem on Windows. The bad news is that the bug is causing memory to be overwritten so the call stack is lost. It says the memcpy is to blame, but it is not one of the many calls to memcpy in the application. I suspect that an assignment is calling memcpy under the covers. This will take a lot more work to debug. Ugh![/QUOTE]

I think it might be as simple as calling gwset_num_threads before gwsetup. This information is in gwnum.h

Does anyone need this to be fixed on Windows? I finally have some time to look into it, but knowing that this will be painful to debug, I'm not overly excited about looking into it. I suspect this is a problem with heap space needed by GMP.