/sys$common/syshlp/helplib.hlb CC, Messages, KEYCOMB  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Message        Illegal combination of keywords.

 Description    An invalid combination of Microsoft keywords was
                encountered during a declaration.  In most cases this
                is because the keywords contradict each other.  One
                example would be using the __fastcall and __stdcall
                modifiers in the same function declaration.  This
                message is only output when the compiler is in
                Microsoft mode.

 User Action    Remove one of the contradictory modifiers.