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

 library_index

    OpenVMS usage:longword_unsigned
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference
    Library control index returned by the LBR$INI_CONTROL routine.
    The library_index argument is the address of the longword that
    contains the index.

 action_routine

    OpenVMS usage:procedure
    type:         procedure value
    access:       modify
    mechanism:    by reference
    User-supplied routine for processing library update history
    records. The action_routine argument is the address of the
    procedure value of this user-supplied routine. The routine is
    invoked once for each update history record in the library.
    One argument is passed to the routine, namely, the address of
    a descriptor pointing to a history record.