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Newsgroups: comp.lang.ada
Date: Fri, 16 Mar 2018 11:06:56 -0700 (PDT)
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Subject: Re: controlled types and point of instanciation
From: Mehdi Saada <00120260a@gmail.com>
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Xref: reader02.eternal-september.org comp.lang.ada:51037
Date: 2018-03-16T11:06:56-07:00
List-Id: <comp.lang.ada>

By the way, I may ask something else related to pointers and this book. Does the preliminary test of this function seems ok ?

function Pointer (Value : Access_Type) return Pointer_Type is
    Object : Pointer_Type;
begin
    if Object.Pointer /= null then
       Delete_Item (Object.Pointer.Value);
    else
       Object.Pointer := new Reference_Counted_Object;
    end if;
    Object.Pointer.all := (Value => Value, Count => 1);
    return Object;
end Pointer;

That Pointer_type has no default values whatsoever, so it doesn't seems necessary to me.
its structure is
type Pointer_Type is new Ada.Finalization.Controlled with
record
     Pointer : Reference_Counted_Pointer;
end record;
and Pointer is a banal access type.
type Reference_Counted_Pointer is access Reference_Counted_Object;
type Reference_Counted_Object is
record
   Value : Access_Type; -- > from generic parameter, points at a non limited unconstrained type.
        type Access_Type is access Item_Type;
   Count : Natural;
end record;