[Boost-users] Newbie question

Hello, I have a problem with interruption of threads. I have one function that I want to run in two different threads with different parameters. When one of the function's instances finishes it stops the other instance. I can't change the function's code, but I can write wrapper to it. My problem is in stopping the other thread. Using timed_join I find which thread is finished, but I can't find a good solution for stopping the second one. How should I use interrupt method correctly or suggest me for correct thread stopping function. BTW, I can't just leave the other thread to run, it's very high CPU consumer. Thank you all.