An information file allows the developer to fine-tune the signature and behavior of a wrapped add-in function. Excel add-in functions typically do not have a fixed return type, since they can often return error values. Methods in other programming environments should have fixed return types, and should throw an exception if an error occurs. An information file contains instructions for the CWGENCLS utility. When you create a new XLL Wrapper project, an information file is created for you, and is added to the project.