Automation components and interfaces that are to be used by the Automation API must be placed in a type library using suitable tools. In some cases, this type library will be supplied as part of the DLL or executable containing the component.
Some of the Automation APIs described in this chapter require you to convert the definitions in the type library into FLI definitions. This is done by compiling and loading a system definition that references the library with the options
:midl-type-library-file. The names in the type library are converted to Lisp symbols as specified in The mapping from COM names to Lisp symbols
Note: this is not required by all the APIs, for example see Calling Automation methods without a type library and A simple implementation of a single Automation interface.
LispWorks COM/Automation User Guide and Reference Manual - 19 Dec 2011