What are oaidl.idl and ocidl.idl for?
A default ATL Simple Object has the following at the top of its IDL file: import "oaidl.idl"; import "ocidl.idl"; What are these files for, and how do I know when I need to import them? Is there any documentation which describes what is defined in these two files? I have no idea what "oa" and "oc" stand for, and there are no helpful c...