NTSTATUS
RtlGetAce(
  IN  PACL Acl,
      ULONG AceIndex,
  OUT PVOID *Ace
  );

Routine Description:

    This routine returns a pointer to an ACE in an ACl referenced by
    ACE index

Arguments:

    Acl - Supplies the ACL being queried

    AceIndex - Supplies the Ace index to locate

    Ace - Receives the address of the ACE within the ACL

Return Value:

    NTSTATUS - STATUS_SUCCESS if successful and an appropriate error
        status otherwise