Re: [ctypes-users] Memory fault using callable restype

[Chris L. <cli...@gm...>]

Barry, Bob wrote:

> 1) With high transaction volume, we always get a memory fault=20
> (segmentation violation) or (once) an illegal instruction. When we=20
> stopped using callable restypes, the problem stopped. Our application i=
s=20
> multi-threaded, with ctypes calls in two threads, so perhaps callable=20
> restypes aren=92t thread-safe? This is on a SunOS 5.8. Of course using =
a=20
> callable restype is not a necessity.

with "callable restypes" you mean that (snippet from the tutorial):
       >>> def ValidHandle(value):
       ...     if value =3D=3D 0:
       ...         raise WinError()
       ...     return value
       ...
       >>>
       >>> GetModuleHandle.restype =3D ValidHandle

hm. i dont use those, but i also experienced crashes with callbacks and=20
threads, see my last post from today.
i wrote a little py extensions for the callbacks and that seems to solve=20
the crashes in our system, altough it would be nice if it would work=20
with ctypes only.

> 2) What should the restype of a void callback function be? I=92m using=20
> c_int for those (as well as other void functions by default) without=20
> problem, but would like to be certain.

i do the same. would be interesting to know...

chris