AddRef and Release function of COM inteface

Hello everyone,


I have noticed a lot of COM samples that the function AddRef and Release function of COM inteface is not synchronized to make it thread safe when dealing with adding/decreasing reference count.

Is it needed to synchronize AddRef and Release? Or the COM runtime underlying implementation handles thread safe issue by itself (i.e. transparent to upper layer COM server developer)

I am using Visual Studio 2005 to develop native (unmanaged C++) COM. No other framework is used (e.g. ATL).


thanks in advance,
George