On Wed, 6 Sep 2017, Graeme Geldenhuys wrote:
Hi,
Playing with this small sample application to answer another question in
this mailing list, I noticed the sample application has a memory leak.
For the life of me I can't see why or how to resolve it.
I tested with FPC 2.6.4, 3.0.2 and 3.0.4-rc1 under 64-bit FreeBSD.
=======================[ project1.pas ]============================
program project1;
{$mode objfpc}{$H+}
{$interfaces COM}
type
IHook = interface
['{4BCAEDD8-92D8-11E7-88D3-C86000E37EB0}']
procedure DoIt;
end;
type
THook = class(TInterfacedObject, IHook)
private
procedure DoIt;
end;
procedure THook.DoIt;
begin
writeln(ClassName + ' did it');
end;
type
TBaseClass = class(TInterfacedObject, IHook)
private
FHook: IHook;
property Hook: IHook read FHook implements IHook;
public
constructor Create;
destructor Destroy; override;
end;
constructor TBaseClass.Create;
begin
FHook := THook.Create; // FPC 2.6.4 reports a memory leak here
end;
destructor TBaseClass.Destroy;
begin
// nothing to do here
end;
You must free FHook here, because you are keeping a reference to the object,
not the interface. And you must call inherited.
You must always call inherited in the destructor.
Michael.
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