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

 Message        Another file in this compilation contains an external
                definition of a function named "<name>", or declares
                it as a variable with external linkage, at <where>.

 Description    In a compilation where interfile optimization has
                been selected (-ifo on UNIX, /PLUS_LIST_OPTIMIZE on
                OpenVMS), the compiler has detected more than one
                definition of a function using the same external
                name, or has found that a function and a variable
                have the same external name.  An external function
                can have only a single definition.  And a given
                identifier with external linkage can refer either to
                a function or to a variable, but not both.

 User Action    Remove or rename one of the names.