Windows/COM events/strange behavior

[Mark Hammond]

Krzysztof Czarnowski wrote:

> Sat, 27 Oct 2001 05:42:26 GMT
> Mark Hammond wrote:
> 
> 
>>As I said, this main thread probably needs to be calling
>>PumpWaitingMessages() each time around the loop.
>>
> Well... This definitely doesn't look very elegant to me!


I don't recall saying it did to me :)  One extra function call in your 
main loop is hardly an imposition though.

> Anyway, if I got it well:
> 
> 1. I should introduce CoInitialize()/CoUninitialize() pair in the main
> thread *and* call PumpWaitingMessages() in its loop? Right? I assume that no
> COM event will be delivered here, or will it?


The main thread does not need a CoInitialize call.  pythoncom 
automatically calls the apartment threaded model version.

> 2. No need to do this in other child threads (like the CORBA thread). Right?


It must be done on every thread that calls any COM function or uses any 
COM objects.


> 3. Will the problem go away if:
> 
>  * the COM event handler is installed in a "free threaded appartment"? (can
> I do this in a threading. thread?)
> 
> or
> 
>  * native Windows threads from ? (now module threading is used)


It depends on the app.  I haven't followed your code/this thread closely 
enough to remember what thread the COM event originates from.


> And generally, what would be *your* favorite solution? (my task is basically
> to receive events from a COM driven subsystem and pass them to a CORBA
> subsystem)


Again, it depends on the app.  However, my favourite solution is 
generally the one that works :)

"Python Programming on Win32" has a reasonably complete discussion on 
threads in COM from Python's POV.

Mark.