IUnknown

In the computer programming of applications on Microsoft Windows through the Windows API, the IUnknown interface is the fundamental interface of Component Object Model (COM). The COM specification mandates that COM objects must implement this interface. Furthermore, every other COM interface must be derived from IUnknown. IUnknown exposes two essential features of all COM objects: object lifetime management through reference counting, and access to object functionality through other interfaces. As well as being a foundational part of Microsoft's COM and DCOM models of objects, there are implem