> >  ffi_convention :stdcall

>

> > before the attach_function call

>
> Confirmed, it works.

Hmm.
Even with :stdcall mine is still segfaulting (1.9.1, 1.8.6)

Could you try this code?
http://gist.github.com/260343

Are you using ffi 0.5.4?

-r