[Tutor] How to close a Tkinter window from a different thread?

[boB Stepp]

On Mon, Apr 20, 2015 at 2:10 AM, Alan Gauld <alan.gauld at btinternet.com> wrote:
> On 20/04/15 04:34, boB Stepp wrote:
>
>> So, how do I:
>> 1) Check for the existence of an already open window from a previous
>> running of the script?
>> 2) If such a window exists, how do I close it from the new script
>> execution? And, then, of course generate a new instance of the
>> information window.
>
>
> I would suggest forgetting about windows and think about
> the processes that create them. Use the OS tools (via
> the os module) to see if the first process is still running.
> If so kill the process - which will in turn kill the window.

I started poking around a little in this area in my books, but did not
know if this was the way to go or not. I was still hung up on how to
identify the correct process...

> You can find the process based on its name or based on
> its PID which you could store in a file somewhere
> (like in /tmp?)

I was thinking in these terms from a Tkinter window id perspective,
but storing the PID while the original window is known to be open
looks like the way to go. Thanks, Alan! I may have more questions on
this later as I have not explicitly worked with this via Python. I've
only killed processes via the command line before.

>> I feel the solution must be in Tkinter's access to the X Window
>> system, but nothing in the documentation is *clicking* with me yet.
>
>
> Trying to manipulate GUIs via the windowing system should always
> be a last resort, it is very hard to get right.

If I am learning nothing else from my exploration of GUI programming,
this is becoming ever more evident!

-- 
boB