| title |
IUnknown | Microsoft Docs |
| ms.custom |
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| ms.date |
11/04/2016 |
| ms.technology |
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| ms.topic |
reference |
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| dev_langs |
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| helpviewer_keywords |
COM interfaces, base interface |
IUnknown interface |
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e6b85472-e54b-4b8c-b19f-4454d6c05a8f |
| author |
mikeblome |
| ms.author |
mblome |
| ms.workload |
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IUnknown is the base interface of every other COM interface. This interface defines three methods: QueryInterface, AddRef, and Release. QueryInterface allows an interface user to ask the object for a pointer to another of its interfaces. AddRef and Release implement reference counting on the interface.
Introduction to COM
IUnknown and Interface Inheritance