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

 Message        <Context> the enum variable "<expression>" is used in
                an arithmetic operation.

 Description    An enumerated type variable was used in an arithmetic
                operation.  While this is valid in C, it might not
                have been what you intended.

 User Action    Verify the use of the enum variable.