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Compiler COM Support
The Visual C++ compiler can directly read component object model (COM) type libraries and translate the contents into C++ source code that can be included in the compilation. Language extensions are available to facilitate COM programming on the client side.
By using the #import preprocessor directive, the compiler can read a type library and convert it into a C++ header file that describes the COM interfaces as classes. A set of #import attributes is available for user control of the content for the resulting type library header files.
You can use the __declspec extended attribute uuid to assign a globally unique identifier (GUID) to a COM object. The keyword __uuidof can be used to extract the GUID associated with a COM object. Another __declspec attribute, property, can be used to specify the get and set methods for a data member of a COM object.
A set of COM support global functions and classes is provided to support the VARIANT and BSTR types, implement smart pointers, and encapsulate the error object thrown by _com_raise_error: