Forum OpenACS Q&A: Re: How to kill Thread
As for your question itself, basically, RTFM.
For POSIX threads there is generally no way to forcibly kill a thread. If you want a thread to die, you must arrange for the thread to stop what's it's doing and exit on its own. Various unix Non-POSIX thread APIs do sometimes provide a forcible kill function. On MS Windows, I've no idea.