Is history repeating itself:
http://lists.freepascal.org/pipermail/fpc-pascal/2016-August/048579.html
On 06/09/17 09:31, 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+}
{$interfaces COM}
type
IHook = interface
['{4BCAEDD8-92D8-11E7-88D3-C86000E37EB0}']
procedure DoIt;
end;
type
THook = class(TInterfacedObject, IHook)
private
procedure DoIt;
end;
procedure THook.DoIt;
begin
writeln(ClassName + ' did it');
end;
type
TBaseClass = class(TInterfacedObject, IHook)
private
FHook: IHook;
property Hook: IHook read FHook implements IHook;
public
constructor Create;
destructor Destroy; override;
end;
constructor TBaseClass.Create;
begin
FHook := THook.Create; // FPC 2.6.4 reports a memory leak here
end;
destructor TBaseClass.Destroy;
begin
// nothing to do here
end;
var
base: IHook;
begin
base := TBaseClass.Create;
base.DoIt;
base := nil; // just to see if it helped with the memory leak - it
doesn't
end.
==============================[ end ]==============================
When I run the program, the output is as follows:
[t1]$ ./project1
THook did it
Heap dump by heaptrc unit
4 memory blocks allocated : 115/120
2 memory blocks freed : 51/56
2 unfreed memory blocks : 64
True heap size : 1114112 (32 used in System startup)
True free heap : 1113696
Should be : 1113760
Call trace for block $000000080072F180 size 32
$0000000000400379 line 35 of project1.lpr
Call trace for block $000000080072F0C0 size 32
Personally I always use CORBA style interfaces, never reference
counted COM style interfaces. So my programs normally don't have this
issue, and I use interfaces a lot.
Regards,
Graeme
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