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

    LBR$PUT_HISTORY writes a new update history record. If the
    library already contains the maximum number of history records
    (as specified at creation time by CRE$L_LUHMAX; see LBR$OPEN for
    details), the oldest history record is deleted before the new
    record is added.