1) "CORBA" FPC interfaces not supprted in Delphi
2) CORBA interfaces lacks of IUnknown base interface (they are initially just empty) -> not reference counted -> not managed by FPC compiler just because of that
3) even Delphi (standart) interfaces can't be freed - only "released" (in Delphi and FPC automagically by compiler then NIL is assigned to interface variable or variable goes out of scope)

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So basically you have to think more about how you would like to design your app. And that you try to do with "CORBA" interfaces...