System.IUnknown.QueryInterface

• Up to Parent: IUnknown

Delphi

function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall;

C++

virtual HRESULT STDMETHODCALLTYPE QueryInterface(    /* [in] */ REFIID riid,
    /* [iid_is][out] */ __RPC__deref_out void __RPC_FAR *__RPC_FAR *ppvObject) = 0;
 
QueryInterface(Q** pp)

Properties

Type	Visibility	Source	Unit	Parent
function	public	System.pas unknwn.h	System	IUnknown

Description

Returns a reference to a specified interface if the object supports that interface.

QueryInterface checks whether the object that implements this interface supports the interface specified by IID. If so, QueryInterface

• Increments the reference count.
• Sets the Obj parameter so that it points to an instance of the specified interface.
• Returns 0 to indicate success.

If the object does not support the interface, QueryInterface returns a nonzero error code, such as E_NoInterface.

See Also

• _AddRef