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c++atlwrl

ComPtr vs CComPtr, As vs QueryInterface

I just want know what exact difference between ComPtr and CComPtr, and whether ComPtr::As() is analogue of CComPtr::QueryInterface()? I read documentation of both, but there is no clear answer to the question...

Solution

  • what exact difference between ComPtr and CComPtr

    They are simply COM interface smart wrappers from different frameworks. ComPtr is part of the Windows Runtime C++ Template Library (WRL). CComPtr is part of the Active Template Library (ATL) . They serve similar purposes for their respective frameworks - to provide automated reference counting and refcount-safe typecasting. But you should not mix them interchangeably. If you are writing WRL code, use ComPtr. If you are writing ATL code, use CComPtr.

    whether ComPtr::As() is analogue of CComPtr::QueryInterface()?

    Yes, because As() simply calls QueryInterface() internally.