Share via

DECLARE_IUNKNOWN

  • Article
 
Microsoft DirectShow 9.0

DECLARE_IUNKNOWN

The DECLARE_IUNKNOWN macro declares the three methods of the base interface for a new interface.

Syntax

#define DECLARE_IUNKNOWN                                        \
    STDMETHODIMP QueryInterface(REFIID riid, void **ppv) {      \
        return GetOwner()->QueryInterface(riid,ppv);            \
    };                                                          \
    STDMETHODIMP_(ULONG) AddRef() {                             \
        return GetOwner()->AddRef();                            \
    };                                                          \
    STDMETHODIMP_(ULONG) Release() {                            \
        return GetOwner()->Release();                           \
    };

Remarks

When you create a new interface, it must derive from IUnknown, which has three methods: QueryInterface, AddRef, and Release. This macro simplifies the declaration process by declaring each of these methods for the new interface.

This macro works only with classes that derive, directly or indirectly, from the CUnknown class.

Requirements

**  Header:** Declared in Combase.h; include Streams.h.

**  Library:** Use Strmbase.lib (retail builds) or Strmbasd.lib (debug builds).

See Also