[python-win32] async COM calls from python

Mark Hammond mhammond at skippinet.com.au
Mon May 23 10:29:37 CEST 2005

> I'm trying to integrate a Python event loop (specifically,
> Twisted's reactor) into a COM in-process server. I've
> discovered CoWaitForMultipleHandles and it seems like it
> might be part of such a solution.

Sadly that is missing from the current pythoncom.  However,
WaitForMultipleObjects is, which does the same thing in a free-threaded

>  Also, I notice that
> ICallFactory::CreateCall allows for calling a COM method and
> not waiting for it to return, which it seems like I'd need
> (since I want my other COM methods to be callable while my
> event loop runs). However, it seems like i need to create a
> new interface to do this, since CreateCall doesn't work with
> IDispatch. Is it even possible to create a new COM interface
> from python?

Not easily.  You may be able to use either ctypes, or abuse some other
interface that has methods which are "close enough".  The connection-point
related ones might be suitable.

> Is there a better way to do event loop integration with COM?

I'm not completely clear on what you are trying to do.  I assume that you
want this event-loop to never block  - one way to do this would be to use
WaitForMultipleObjects, a queue and a thread-pool.  I'm not sure how
ICallFactory is implemented, so I'm not sure how efficient it is to create a
huge number of pending calls - a queue etc would let you have more control
over this process.


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