From: Guido van Rossum <guido@CNRI.Reston.Va.US>
Subject: Re: Tkinter mainloop and threads in win32
Date: Tue, 22 Sep 1998 03:33:24 GMT

> Hi, I am trying to write an TkInter app which has a listbox that is altered
> from time to time. So what I do is start_new_thread which listens to a port
> and whenever something arrives it write it to the listbox. Sounds trivial.
> The code looks somewhat like this:
> 
> import thread
> 
> class MyGui(Frame):
>   ...
> 
> def listenToPortThreadProc():
>   ...
> 
> gui=MyGui()
> thread.start_new_thread(listenToPortThreadProc, ())
> gui.mainloop()
> 
> When running this code and sending data through the port I first have to click
> several times on the listbox before the list is updated.
> It looks as if the spawned thread has almost no priority (kind of starvation).
> Even the easier example where the listenToPortThreadProc just updates the
> listbox directly reacts the same.
> Is this just a win32 problem?
> Any hints...
> 
> Clemens
> BTW: WinNT4.0 SP3, Python 1.5.1, Tcl/Tk8.0(latest)

Sorry, threads and Tkinter (or threads and Tcl/Tk!) are not usable
together.  In 1.5.2 (in alpha for PSA members!) this will work, sort
of, but there will still be problems, especially on Windows.

I wish I could help you, but Ousterhout has made it clear that Tk will 
(probably) never be thread-safe :-(

--Guido van Rossum (home page: http://www.python.org/~guido/)