Killing a Specific Thread Python

Question

Is there a way to kill a specific thread with Python? I have a thread running a function that is a loop and it is interfering with other parts of the program. I need to kill it when a certain function is started, is there a way to do this?

If you have to *kill* a thread for your program to work correctly, you're doing something *very wrong*. — Jonathon Reinhart, Aug 07 '12 at 21:40
Make the loop periodically check some boolean variable, let it be `proceed`. In main thread, set `proceed = False` when the other thread should stop; it will stop on next iteration. — 9000, Aug 07 '12 at 21:43
Can you describe the problem more? perhaps there's a better solution. I mean there's definitely a better solution than just killing the thread. But, perhaps you could use a threading.Lock() object to fix your issues — Ryan Haining, Aug 07 '12 at 21:59

score 2 · Answer 1 · edited May 23 '17 at 11:48

2

The best way to do this is to use an exit flag that the thread periodically checks, and exits if it is set. When you need to kill the thread, you would set this flag and wait for the thread to exit on its own.

This answer has additional information on why forcibly killing a thread is a bad idea, and a Python implementation for the above method.

edited May 23 '17 at 11:48

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answered Aug 07 '12 at 21:43

Andrew Clark

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Chris W · Answer 2 · 2017-12-12T19:38:48.773

I found that if you define a Threading class with a self.flag variable, and make the function you are calling a function of the class, you can then set the flag on a thread specific instance and exit specific threads with an if statement.

It's not hard to imagine this more dynamic and allowing for the ability to spawn and close threads.

class AutoPilotThreader(threading.Thread):
    def __init__(self, threadID, name):
      threading.Thread.__init__(self)
      self.threadID = threadID
      self.name = name
      self.flag = 0
    def run(self):
      print "Starting " + self.name
      self.SelTestRun()
      print "Exiting " + self.name

    def SelTestRun(self):
        # do code
        while 1:
            if self.flag:
                return
            else:
                time.sleep(1)


my_threads = []
t1 = AutoPilotThreader(1, "t1")
t2 = AutoPilotThreader(2, "t2")
t1.start()
t2.start()
my_threads.append(t1)
my_threads.append(t2)


while 1:
    print("What would you like to do: 1. Quit 2. Start New 3. Check")
    choice = input("Enter : ")
    if choice == 1:
        choice = input(" 1 or 2 or 3 ")
        if choice == 1:
            t1.flag = 1
        elif choice ==2:
            t2.flag = 1
        elif choice ==3:
            t3.flag = 1  .........

Killing a Specific Thread Python

2 Answers2