Re: Running two different ActiceX controls in the same browser.

"Alexander Nickolov" <>
Tue, 15 Apr 2008 10:24:29 -0700
Perhaps GetCurrentProcessId() is what you are after?

Alexander Nickolov
Microsoft MVP [VC], MCSD

"Janusthorne" <> wrote in message

I have a common C++ code base that compiles two different ActiveX-based
(let's call them 3dApp and 2dApp). They share most of the compiled DLLs as
well as several non-proprietary DLLs (windows, etc). They are installed in
different locations on the client. Currently, I am using a singleton
mechanism to prevent more than one version of either application to be run
the same browser (eg. 3dApp+3dApp). That works just dandy. I can obviously
run both in separate browsers (3dApp in IE and 2dApp in FF) or in separate
instances of the same browser (3dApp in IE#1 and 2dApp in IE#2), not an
issue. But when I try launching either one in the same browser when the
is running I get all sorts of DLL sharing issues. I tried using a common
Mutex which detects if either of the other is running and prevents the
one from launching but then that eliminates the ability to have both
in separate browsers/browser_instances.

I'd like to avoid creating completely distinct DLL sets for both apps if
possible as that would be a logisitcal nightmare.

Without going into any great detail the primary DLL (3dApp) holds an
instance of an ATL COM module and an instance of the engine that drives
application (either an activeX or Gecko plugin). The second DLL (2dViewer)
uses the same design. The two DLL's are named and registered separately of
course (as state above).

This is legacy code, so refactoring it is out of the question at this
in the development. Use of singleton DLL's will of course be phased out
during the refactoring stage at a later date but for now I'm stuck in this

What I really need now is a mechanism to determine if the thread
to use either of these DLL's is the same thread that is already using it's
companion DLL. This is not the most ideal solution to the problem but it
should work in the short term. Obviously I can't have the browser pass
ID along to the DLL (or can I?) so I would probably need some way to query
the calling process's ID from a DLL common to both applications, compare
results and either allow the second app to launch if the ID is not the
or disallow it if it is.

Any ideas?

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