Essential COM

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. , , . , IDL (Interface Definition Language). IDL- (communications code), .

IUnknown - , . IUnknown. , IUnknown. IUnknown , , . QueryInterface . IUnknown "void *" ( ) , , " " (is "cast") - QueryInterface.

, IUnknown . IUnknown (promises), . . IUnknown C++ . IUnknown C++, , QueryInterface . , , .