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

    LBR$_HDRTRUNC      Buffer supplied to hold the module header was
                       too small.
    LBR$_ILLCTL        Specified library control index not valid.
    LBR$_ILLOP         Error. The updatedesc argument was supplied
                       and the library was a Version 1.0 library or
                       the library was opened only for read access.
    LBR$_INVRFA        Specified RFA does not point to a valid module
                       header.
    LBR$_LIBNOTOPN     Specified library not open.