VMS Help System Services, $PURGWS, Argument  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 inadr

    OpenVMS usage:address_range
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference
    Starting and ending virtual addresses of the range of pages to be
    purged. The inadr argument is the address of a 2-longword array
    containing, in order, the starting and ending process virtual
    addresses. The addresses are adjusted up or down to fall on CPU-
    specific page boundaries. Only the virtual page number portion of
    each virtual address is used; the low-order byte-within-page bits
    are ignored.