[python-win32] Regarding Threads and locals()

[Mike Driscoll]

> Message: 6
> Date: Thu, 20 Mar 2008 16:07:15 +0530
> From: "Tejovathi P" <tejovathi.p at gmail.com>
> Subject: [python-win32] Regarding Threads and locals()
> To: python-win32 at python.org, py2exe-users at lists.sourceforge.net
> Message-ID:
> 	<aefc0fa70803200337l60d18f2bj3422e19ae95de1a8 at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> Hi all,
> 
> I have a GUI applicaion(along with threads). When the run 
> button is pressed
> in the GUI a separate thread starts( Thread is created using 
> beginthreadex)
> and does the
> required activity.
> Now, while the thread is being executed, i want the locals() 
> present inside
> the thread's run function to be avaialbe in the GUI class 
> from where the
> thread class is being created
> 
> EG:
> 
> *main.py*
> 
> class WorkerThread(threading.Thread):
> 
>     def __init__(self, ):
>          threading.Thread.__init__(self)
>          # Start the thread and invoke the run method
>          self.start()
> 
>     def run(self):
>           # Start the thread. It executed self.func() as a 
> separate thread
>           self.workerThread, tid = 
> win32process.beginthreadex(None, 0 ,
> self.func ,(), 1)
>           .......
> 
>      def func(self):
>            execfile(temp.py)
> 
> class GUI(wxFrame):
>        def __init__(self):
>            .....
>            .....
>        def  CreateThread(self):
> 
>              self.workerThread = WorkerThread()
> 
> 
> if name == _main_:
>         .....
> .        ....
> .        .....
> 
> *temp.py*
> 
>   i = 1   j = 2
>   k = 4
>   while(10000):
>         print i
>         print j
>         print k
>         i = 1+1
>         j = j+2
>         k = k + 3
> 
> 
> Now, while the thread is executin func and printing i, j, k , 
> In the main
> GUI thread how do i get the values of i, j ,k
> I tried with sys.modules, sys._current_frames, vars(). But 
> nothing worked
> out.
> 
> Ideally the locals() of func() should be passed to the GUI 
> thread, how?


One of the recommended ways of doing this is to have the thread write that
information to a file either send an event to the GUI that there's data
there or use a timer in the GUI event loop that looks for that file. I'm
actually messing with Tim Golden's watch_directory.py file for a VPN
project I'm working on in which my wxPython GUI app watches a file for
changes and then reads it.

You can check out Golden's work here:
http://tgolden.sc.sabren.com/python/win32_how_do_i/watch_directory_for_cha
nges.html

The Python docs talk about using the threading module's event object for
basic communication, which is what I was talking about: 

http://docs.python.org/lib/event-objects.html

In wxPython, I can wait for a threading event and then use a wx.PostEvent
to let my GUI know that the thread had an event. I'm sure there are
similar methods in Tkinter and pyGTK or whatever you're using.

Mike