Re: Qs re 'Write & 'Read

[tmoran@acm.org]

>Maybe my mind's just in a fog today, but please explain why there'd be
>a problem with any kind of access type -- general, or not, using my
>approach.
  Aliasing.
  type phs is access integer;
  type pgs is access all integer;
  type r is record
    i : aliased integer;
    ph : phs;
    pg : pgs;
  end record;
  x : r;
begin
  x.ph := new integer;
  x.pg := x.i'access;
but on reading it back in, you can tell both x.ph and x.pg are non-null,
but you don't know whether x.pg should allocate from the heap or point
to some existing (stack) object.