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extern "C" InterfacePtr DLLCreate( void ) { return InterfacePtr( new InterfaceImpl ); }

At the moment this code doesn't compile because VS7.1 complains that it a function with extern "C" linkage can't return a shared_ptr<Interface> instance. How could I implement the desired behavior?

Either omit the extern "C" or, if you must use a C-style interface, do this:

extern "C" Interface* DLLCreate() { return new InterfaceImpl; }

extern "C" void DLLDestroy( Interface* p ) { delete p; }

and then construct an InterfacePtr( DLLCreate(), DLLDestroy ). You'll need a public virtual destructor in this case, though.

When writing plugins under linux (i.e. with 'dlopen' etc.), I believe I have already used a function returning a std::auto_ptr as entry point for the loader. What is wrong with that ? Is your advice above simply due to a limitation with MSVC ? Regards, Stefan