Re: EXE COM Singleton

I've been working on an "Audio Router" for the last couple of years. Its
been in production code for the last year. Now all of a sudden we are
starting to see deadlocks. I was most definitely a beginner when I
started the project and still have a lot to learn.

The Audio Router is implemented as an out of process COM server, singleton
(using DECLARE_CLASSFACTORY_SINGLETON) using MTA thread model. I had to
make this a singleton so multiple clients can have access to the
microphone and sound buffers. The clients control the publish/subscribe
states for audio to multiple DirectPlay groups my making calls on the
Audio Router. As specific events happen (received from a DirectPlay
message handler) callbacks are made to the clients through a provided
callback interface (the callback interfaces are stored in a global
interface table). When things reach a deadlock state, I can step into the
debugger and see that several threads are stopped while invoking a
function on Audio Router (some threads start from the DirectPlay callback,
others start from clients calling into Audio Router).

With that said, I have to assume that this is an issue of making Audio
Router a singleton. I have seen allot about not using singletons, but
that it could be done using an EXE COM Server... if done properly. Can
anyone point me to a resource that would explain the "done properly" part.
I've also read that singletons are not necessary if you use static or
global member variables. Will this work if I create a "Audio Router
Factory" (not an actual COM factory) that wraps a static pointer to the
Audio Router interface. Then provide a "get interface" method to return
the interface properly marshaled for the calling thread?

Thanks in advance,
Aaron Smith