(Alpha and I64 only.) The Get Virtual Memory Page routine
    allocates a specified number of contiguous Alpha or I64 pagelets
    of memory in the program region and returns the virtual address
    of the first allocated pagelet.
    Format
      LIB$GET_VM_PAGE_64  number-of-pages ,base-address
1 – Returns
    OpenVMS usage:cond_value
    type:         longword (unsigned)
    access:       write only
    mechanism:    by value
2 – Arguments
 number-of-pages
    OpenVMS usage:quadword_signed
    type:         quadword integer (signed)
    access:       read only
    mechanism:    by reference
    Number of Alpha or I64 pagelets. The number-of-pages argument is
    the address of a quadword integer that specifies the number of
    contiguous Alpha or I64 pagelets to be allocated. The value of
    number-of-pages must be greater than 0.
 base-address
    OpenVMS usage:address
    type:         quadword (unsigned)
    access:       write only
    mechanism:    by reference
    Block address. The base-address argument is the address of a
    quadword that is set to the address of the first byte of the
    newly allocated block of Alpha or I64 pagelets.