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.

 record_desc

    OpenVMS usage:char_string
    type:         character string
    access:       read only
    mechanism:    by descriptor
    Library history record. The record_desc argument is the address
    of a string descriptor pointing to the record to be added to the
    library update history.