VMS Help BACKUP_API, BACKUP$START, Condition Values Returned  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    SS$_NORMAL         Normal successful completion.
    BACKUP$_BADOPTDSC  Invalid callable interface option descriptor.
    BACKUP$_BADOPTTYP  Invalid callable interface option type.
    BACKUP$_BADOPTVAL  Invalid callable interface option value.
    BACKUP$_           Invalid callable interface option value.
    BADOPTVALQ
    BACKUP$_DUPOPT     Previously specified callable interface option
                       type invalid.
    BACKUP$_NOAPIARGS  Callable interface required parameter not
                       specified or invalid.

    Any condition value returned by the OpenVMS Backup utility.