Logo Questions Linux Laravel Mysql Ubuntu Git Menu
 

Python Threading with Event object

I've seen a lot of Python scripts that use Threads in a class and a lot of them use the threading.Event(). For example:

class TimerClass(threading.Thread):     def __init__(self):         threading.Thread.__init__(self)         self.event = threading.Event()      def run(self):         while not self.event.is_set():             print "something"             self.event.wait(120) 

In the while loop, why do they check the condition if they don't set self.event?

like image 711
user2724899 Avatar asked Aug 28 '13 10:08

user2724899


1 Answers

Because someone else will set it.

You generally start a thread in one part of your application and continue to do whatever you do:

thread = TimerClass() thread.start() # Do your stuff 

The thread does it's stuff, while you do your stuff. If you want to terminate the thread you just call:

thread.event.set() 

And the thread will stop.

So the answer is: event, in this case, is not used for controlling the thread from inside the thread object itself. It is used for controlling the thread from outside (from the object which holds the reference to the thread).

like image 120
Viktor Kerkez Avatar answered Oct 10 '22 00:10

Viktor Kerkez