If I have a thread in an infinite loop, is there a way to terminate it when the main program ends (for example, when I press Ctrl+C)?
Check this question. The correct answer has great explanation on how to terminate threads the right way: Is there any way to kill a Thread in Python?
To make the thread stop on Keyboard Interrupt signal (ctrl+c) you can catch the exception "KeyboardInterrupt" and cleanup before exiting. Like this:
try: start_thread() except (KeyboardInterrupt, SystemExit): cleanup_stop_thread() sys.exit()
This way you can control what to do whenever the program is abruptly terminated.
You can also use the built-in signal module that lets you setup signal handlers (in your specific case the SIGINT signal): http://docs.python.org/library/signal.html
If you make your worker threads daemon threads, they will die when all your non-daemon threads (e.g. the main thread) have exited.