problem with tkinter and multiprocessing

[deanhystad]

When you start a process the process loads the module (at least in Windows). This runs "window = Tk()" for each process. Protect the tkinter code behind the if __name__ == '__main__'. I think in Linux/Unix processes are spawned using "fork" and it inherits knowledge about the module instead of having to reload the code. I think you program would run differently under Linux or on a Mac. The code below should work everywhere.

from multiprocessing import Process
from tkinter import *
 
def f1():
    print(1)
 
def f2():
    print(2)
 
def main():
    p1 = Process(target=f1)
    p1.start()
    p2 = Process(target=f2)
    p2.start()
    p1.join()
    p2.join()
 
if __name__ == '__main__':
    window = Tk()
    main()
    window.mainloop()