Best Practice For Killing Thread?

All:

I am using Perl v5.8 w/ithreads and have a thread which is a UDP
listening socket that listens for messages in a perpetual read loop. 
There are times that this socket needs to be broken down along with the
corresponding thread.

What is the current best practice for killing a single thread with
ithreads?

If the answer is to kill the process, please suggest ways to obtain the
pid.

Thanks and best,

Steve