Re: [fpc-pascal] Delegate Interface class does not seem to be referenced counted

[Graeme Geldenhuys]

On 2016-08-10 13:42, Tony Whyman wrote:
> In the example, TMyClass is the interface class doing the delegation and 
> while TDelegateClass is being destroyed when it goes out of scope, 
> TMyClass is not.

Maybe I'm missing something, but here is a quick example I put together.
Testing with FPC 2.6.4 under FreeBSD and classes are created and freed
as they are supposed to.

Here is the console output:

$ ./test2
Creating TMyClass
Creating TMyInterface
TMyInterface.P1
TMyInterface.P2
Destroying TMyClass
Destroying TMyInterface

And the code for the test project.

===================[ test2.pas ]=======================
program test2;

{$mode objfpc}{$H+}

{ Delegating to an interface-type property }

type
  IMyInterface = interface
    procedure P1;
    procedure P2;
  end;

  TMyInterface = class(TInterfacedObject, IMyInterface)
  private
     procedure P1;
     procedure P2;
  public
    constructor Create;
    destructor Destroy; override;
  end;

  TMyClass = class(TObject, IMyInterface)
    FMyInterface: IMyInterface;
    property MyInterface: IMyInterface read FMyInterface implements
IMyInterface;
  public
    constructor Create;
    destructor Destroy; override;
  end;


procedure TMyInterface.P1;
begin
  writeln('TMyInterface.P1');
end;

procedure TMyInterface.P2;
begin
  writeln('TMyInterface.P2');
end;

constructor TMyInterface.Create;
begin
  writeln('Creating ',ClassName);
end;

destructor TMyInterface.Destroy;
begin
  writeln('Destroying ',ClassName);
  inherited Destroy;
end;



var
  MyClass: TMyClass;
  MyInterface: IMyInterface;

{ TMyClass }

constructor TMyClass.Create;
begin
  writeln('Creating ',ClassName);
end;

destructor TMyClass.Destroy;
begin
  writeln('Destroying ',ClassName);
  inherited Destroy;
end;

begin
  MyClass := TMyClass.Create;
  MyClass.FMyInterface := TMyInterface.Create;  // some object whose
class implements IMyInterface
  MyInterface := MyClass;
  MyInterface.P1;
  MyInterface.P2;
  MyClass.Free;
end.

========================[ end ]========================

Regards,
  Graeme

-- 
fpGUI Toolkit - a cross-platform GUI toolkit using Free Pascal
http://fpgui.sourceforge.net/

My public PGP key:  http://tinyurl.com/graeme-pgp
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