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From: Didier Pieroux <dpieroux@pi.be>
Newsgroups: comp.lang.ada
Subject: [HELP] Why is 'Adjust' not called here ???
Date: Tue, 05 Feb 2002 11:48:32 +0100
Organization: Free University of Brussels (ULB)
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Hello,

To make it short: why is 'Adjust' not called during initialization by a
aggregate ?

I give an example below illustrating my question.  'A.Instance' is a
controlled type with Initialize, Adjust and Finalize redefined to print
their name. 

I thought that the elaboration of

   Item1 : A.Instance := (Ada.Finalization.Controlled with 10);

would call the 'A.Adjust' procedure... It is not the case. However,
'A.Adjust' is called as expected after the elaboration of

   Item2 : A.Instance := Item1;

I check that behavior with both the Gnat and Aonix compiler.  So, I am
clearly missing something here, and I can't find the answer in my books
(Barnes, Cohen, Ben-Ari and the RM) 

Also, could someone
- Explain me the rational for not calling 'Adjust' in the first case ?
- Give me the key reference(s) in the RM from which this behavior can be
deduced ?

Thank in advance for the light !
Didier



== a.ads =============================================================

with Ada.Finalization;

package A is
   type Instance is new Ada.Finalization.Controlled with
      record
         N: Integer;
      end record;

   procedure Initialize(Self: in out Instance);
   procedure Adjust    (Self: in out Instance);
   procedure Finalize  (Self: in out Instance);
end A;

== a.adb =============================================================

with Ada.Text_Io;
use Ada.Text_Io;

package body A is
   procedure Initialize(Self: in out Instance) is
   begin
      Put_Line("Init");
   end;

   procedure Adjust(Self: in out Instance) is
   begin
      Put_Line("Adjust");
   end;

   procedure Finalize(Self: in out Instance) is
   begin
      Put_Line("Finalize");
   end;
end A;

== my_test.adb =======================================================

with Ada.Finalization;
with A;

procedure My_Test is
   Item1 : A.Instance := (Ada.Finalization.Controlled with 10);
   Item2 : A.Instance := Item1;
begin
   null;
end My_Test;

== Result: ===========================================================

~/Ada/test > gnatmake my_test.adb
gnatgcc -c my_test.adb
gnatgcc -c a.adb
gnatbind -x my_test.ali
gnatlink my_test.ali
~/Ada/test > my_test
Adjust      <-- this corresponds to the Item2 elaboration.
Finalize
Finalize
~/Ada/test >        

-- 
     _________________________________________________________________ 

     Didier Pieroux
     Theoretical Nonlinear Optics, CP 231
     Physics Department, Universite Libre de Bruxelles
     Bvd du Triomphe, B-1050 Brussels, Belgium

     Phone: ++ 32 2 650 5903, Fax: ++ 32 2 650 5824
     dpieroux@hotmail.com
     _________________________________________________________________