COM+ contains a superset of the functionality of MTS. In the case of MSMQ, the concepts and implementation are considerably different in COM+ than in the original MSMQ. In the original, all objects had to know that they were supporting MSMQ, and had to agree message formats etc. In COM+, use of asynchronous calls is more of less invisible to the client. Get hold of a copy of COM and .NET Component Services by Juval Lowy. It's available online at http://safari.oreilly.com too.

Thanks very much for that, just what I was after :-)

Hello all What I am trying to do is implement a function in an ATL COM server that returns an array of objects. I need to be able to use these objects from VB. My searches on the net turned up lots of references to using SAFEARRAY(VARIANT), but very little sample code. Ideally, I'd love a link to some code that declares a method like GetObjects([in,out] SAFEARRAY(VARIANT) *ppObjects) and shows both the implementation in C++ (including creating and populating the SAFEARRAY with IUnknown-derived object pointers) and some calling code, either in VB or C#. Thanks all Ian