C ++ com component event notes

[
    object,
    uuid(AECE8D0C-F902-4311-A374-ED3A0EBB6B49),
    dual,
    nonextensible,
    pointer_default(unique)
]
interface ICallbacks : IUnknown
{
    [id(1)] HRESULT UserExit([in] int errorCode, [in] BSTR errorMessage);
    [id(2)] HRESULT UserAttemptingReconnection();
    [id(3)] HRESULT UserReconnected();
};

[
    object,
    uuid(B98A7D3F-651A-49BE-9744-2B1D8C896E9E),
    dual,
    nonextensible,
    pointer_default(unique)
]
interface ICerberusSession : IDispatch {
    ...
    [id(5)] HRESULT SetCallbacks([in] ICallbacks* callbacks);
};