[python-win32] Multithreaded COM, when do I need to CoUninitialise?

[Peter Mott]

CoUninitialize frees resources that were used when the COM libraries were
intialized with CoInitialise. BTW as you are using the Dispatch interface which
is what scripting languages like VBscript use I don't see why you need to
initialise COM directly.

Peter

> -----Original Message-----
> From: python-win32-bounces at python.org
> [mailto:python-win32-bounces at python.org]On Behalf Of Moof
> Sent: 10 October 2003 09:50
> To: python-win32 at python.org
> Subject: [python-win32] Multithreaded COM, when do I need to
> CoUninitialise?
>
>
> I'm currently writing a Webware app (http://webware.sf.net/), which uses
> multiple threads to serve web requests in the application server.
>
> Due to the nature of my application, I have to save a number of COM
> objects in my sessions, which are held in memory, for about 15-30
> minutes, which is when the session times out and is garbage collected.
>
> After playing around with the COMKit part of Webware and deciding it
> isn't as simple as it looks, I now find I'm doing a little something
> like this:
>
> import sys
> sys.coinit_flags = 0
> import pythoncom
> from Webkit.Page import Page
> from win32com.client import Dispatch
>
> class FooPage(Page):
> 	def procThatGetsCalledToSetUpData(self):
> 		#first reinit COM, in case this thread hasn't inited it
> 		pythoncom.CoInitializeEx(pythoncom.COINIT_MULTITHREADED)
> 		foo = Dipatch('comlib.object1')
> 		#do stuff with foo
> 		bar = Dispatch('comlib.object2')
> 		bar.doStuff(foo)
> 		self.session().setValue('foo',foo)
> 		self.session().setvalue('bar',bar)
> 		#And here I used to CoUninitialize()
> 		self.writePage()
>
> The reason I *used* to CoUninitialize there was that at the time, I
> didn't need the com objects anymore, but now I find that I do, and need
> to store them in the session.
>
> The thing I suppose I'm wondering is whether I need to worry about
> CoUninitialize - I have no control over which thread will be working
> with the COM objects later, and I can't even force the user to go
> through a set path in my webpage, the session might never reach
> completion. Basically, I don't know what CoUninitialize does exactly,
> and whether using it is just being "good neighbourly" or whether it's
> actually really necessary.
>
> Since I'm asking, given that a thread may call CoInitializeEx() a number
> of times throughout its lifetime, is that going affect the COM Objects
> that are currently being stored in a session somewhere when I try to
> import them back into that thread?
>
> Thanks in advance,
> Moof
> --
> G.A.Radford - Moofing at you from Madrid, Spain
> 'Intelligence, Khalis, and Eupathy'
>
>
>
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