All IDL definitions map onto FLI definitions, mirroring the mapping that
does for C/C++. However, IDL provides some additional type information that C/C++ lacks (for instance the
attribute), so there are some additional conversions that Lisp performs when it can. For a complete example of data conversion, see the file
in the LispWorks installation.
LispWorks COM/Automation User Guide and Reference Manual - 19 Dec 2011