VMS Help LBR Routines, LBR$PUT_END, Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Call LBR$PUT_END after you write data records to the library
    with the LBR$PUT_RECORD routine. LBR$PUT_END terminates a module
    by attaching a 3-byte logical end-of-file record (hexadecimal
    77,00,77) to the data.