VMS Help CC, Messages, CANNOTREDEF  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Message        Cannot #define a macro that is currently expanding.

 Description    The program is trying to #define the same macro it is
                currently expanding.  The #define will be ignored.

 User Action    Remove the #define, or move it after the expansion of
                the macro.