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

 Message        Use of /ROUNDING_MODE qualifier implies /FLOAT=IEEE.
                Compilation will be performed as if /FLOAT=IEEE were
                specified on the command line.

 Description    This compilation has specified an IEEE floating-point
                rounding mode without specifying /FLOAT=IEEE on the
                command line.  The compiler will set the
                floating-point type to IEEE floating.

 User Action    Specify /FLOAT=IEEE on the command line.