CODEWITHSUNDEEP
pythonpython-3.xtkinterpython-multiprocessingtraceback
Anonymous
Anonymous

Reputation: 754

Python 3.x multiprocessing tkinter mainloop

How do you use multiprocessing on root.mainloop? I am using Python 3.6. I need to do lines of code after it, some requiring the object.
I do not want to create a second object, like some of the other answers for my question suggest. Here is a little code snippet (set being a JSON object):

from multiprocessing import Process
def check():
    try: sett['setup']
    except KeyError:
        sett['troubleshoot_file']=None
        check()
    else:
        if sett['setup'] is True: return
        elif type(sett['setup']) is not bool: raise TypeError('sett[\'setup\'] is not a type of boolian (\'bool\')')
    root.=Tk()
    root['bg']='blue'
    mainloop=Process(target=root.mainloop)
    mainloop.start()
    mainloop.join()
check()

However, I get this traceback:

Traceback (most recent call last):
  File "(directory)/main.py", line 41, in <module>
    check()
  File "(directory)/main.py", line 39, in check
    mainloop.start()
  File "C:\Program Files (x86)\Python36-32\lib\multiprocessing\process.py", line 105, in start
    self._popen = self._Popen(self)
  File "C:\Program Files (x86)\Python36-32\lib\multiprocessing\context.py", line 223, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "C:\Program Files (x86)\Python36-32\lib\multiprocessing\context.py", line 322, in _Popen
    return Popen(process_obj)
  File "C:\Program Files (x86)\Python36-32\lib\multiprocessing\popen_spawn_win32.py", line 65, in __init__
    reduction.dump(process_obj, to_child)
  File "C:\Program Files (x86)\Python36-32\lib\multiprocessing\reduction.py", line 60, in dump
    ForkingPickler(file, protocol).dump(obj)
TypeError: can't pickle _tkinter.tkapp objects

I have tried running:

from queue import Queue
from tkinter import Tk
from multiprocessing import Process
p=Process(target=q.get())

The interpreter then completely crashes.

Upvotes: 1

Views: 1652

Answers (1)

Bryan Oakley
Bryan Oakley

Reputation: 385960

You cannot use any tkinter objects across multiple processes or threads. If you need to share data between the gui and other processes you will need to set up a queue, and poll the queue from the GUI.

The reason for this is that tkinter is a wrapper around a tcl interpreter that knows nothing about python threads or processes.

You will find a link on how to do this at: docs.python.org/3.6/library/queue.html

Upvotes: 2

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