[Tkinter-discuss] Main loop / Scheduling

[Alec Solway]

Hi all,

I'm debugging an existing application which uses Tkinter. Having not  
worked much with the library... please bear with me. In general, how  
is invocation of the event handler/dispatcher scheduled?

The application in question is a Tcl/Tk library written in C; a Python  
interface using Tkinter sits on top of it. It seems to start the main  
loop implicitly by creating a Tkinter.Tk object (is this true of how  
the loop gets started?). The underlying C library schedules a task to  
run at a set interval with Tcl_CreateTimerHandler(...). If I'm not  
running any code outside of this framework, all is good. However, if I  
run anything in Python-space (say, just a really long loop that prints  
numbers, for testing), invocation of the scheduled task is delayed  
until this other task is done. My questions then are:

(1) Is this an inherit problem with how things in general are set up?  
Is everything running under a single thread?

(2) If not, is it possible to bump up the priority of the Tcl/Tk main  
loop and have it preempt Python space more often (or at all!), or  
conversely, downgrade the priority of the Python space process?

(3) If option 2 fails, are there other alternatives anyone can think  
of to have these two things co-operate?


Thanks for your help.