Thread killing - I know I know!

[inhahe]

I'm not sure it's possible to kill a thread in Python that's in the middle
of a C function.  I know you can't do it with signals, for example.  Or can
you?  I'm on Windows and signals isn't fully implemented.

I had to do just this, btw, so I wrote another Python program that
communicates with the main one over a socket and then if it misbehaves I can
kill it using an OS command because it's a process and there's an OS command
for killing processes, and then I'd restart it.  The problem is that,
sometimes the OS kill command would work, sometimes it wouldn't, and I never
did figure what makes the difference.



"Roger Heathcote" <usenet at technicalbloke.com> wrote in message
news:DZSdnYx_IraeNrDVnZ2dneKdnZydnZ2d at bt.com...
> Hello everyone, this is my first post so hello & please be gentle!
>
> Despite many peoples insistence that allowing for the arbitrary killing of
> threads is a cardinal sin and although I have no particular threading
> problem to crack right now I remain interest in the taboo that is thread
> killing. The real world and it's data are messy and imperfect and I can
> think of several scenarios where it could be useful to be able to bump off
> a naughty thread, especially when using/testing unstable 3rd party modules
> and other code that is an unknown quantity.
>
> With this in mind I am experimenting with a set of threading subclasses
> that would permit timeouts and the manual killing of threads. I'm trying
> to evaluate how robust such a scheme can be made and what the limitations
> would be in practice.
>
> So far I can seemingly murder/timeout pure python threads that are stuck
> blocking for input and stuck in infinite loops but I'm guessing there are
> many more awkward cases. What I'm looking for are examples of code/modules
> that can get stuck in dead ends or might otherwise be problematic to
> terminate.
>
> In particular I'd be interested to see if I could kill a non-returning c
> module. Of course naturally no one wants to be publishing buggy modules
> and the like so I am having trouble finding examples of misbehaving c code
> to explore further. I figure I could learn how to write c modules for
> python but, while it's something I'd like to know someday, I'm guessing
> that will be too long to fit into the immediate future :/ Consequently if
> anyone has detailed knowledge of what is and isn't fundamentally possible
> in the world of thread culling, or if you can point me to some
> gnarly/non-returning thread code to test with I would be forever grateful.
>
> Oh yes, I'm working primarily with 2.5 on XP however I have access to
> linux & OSX boxen and I'd be interested to learn about problematic thread
> code for either of those platforms as well.
>
> Thanks for reading,
>
> Roger Heathcote - www.technicalbloke.com