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On windows, to stop and destroy an anonymous thread, i simply do FmyTask.free => that will call destroy => and that inside the destroy will set terminate = true and call waitfor to wait the task is finished => and finally clean the memory used

but on ARC, everything is different 🙁
i use this code :

TMyObject
private
FMyTask: TThread;
public
destructor Destroy; override;
procedure DoSomething;
end;

destructor TMyObject.Destroy;
begin
FMyTask.free; // << will do nothing because FMyTask.refcount = 2 !! how it’s possible ?
FMyTask:= nil;
inherited;
end;

procedure TMyObject.DoSomething;
begin

FMyTask:= Thread.CreateAnonymousThread(
procedure
begin
sleep(10000000);
end);
FMyTask.FreeOnTerminate := False;
FMyTask.Start;

end;

and i do nothing else than just

MyObject := TmyObject.create;
MyObject.DoSomething;
MyObject.free;
MyObject := nil;

but as you see, in the onDestroy of TmyObject, FMyTask have a refcount of 2 !! so it’s mean that the FMyTask will be not destroyed (refcount will be decreased to 1) with TmyObject (but later) and you imagine all the bug that can results 🙁

it’s sean that a reference to fMyTask is keep inside this function :

function ThreadProc(const Thread: TThread): Integer;
var
FreeThread: Boolean;
{$IFDEF MACOS}
pool: Pointer;
{$ENDIF MACOS}
begin
{$IFDEF AUTOREFCOUNT}
Thread.__ObjAddRef; // this ensures the instance remains for as long as the thread is running
{$ENDIF}
TThread.FCurrentThread := Thread;
{$IF Defined(POSIX)}
if Thread.FSuspended then
pthread_mutex_lock(Thread.FCreateSuspendedMutex);
{$ENDIF POSIX}
{$IFDEF MACOS}
// Register the auto release pool
pool := objc_msgSend(objc_msgSend(objc_getClass(‘NSAutoreleasePool’),
sel_getUid(‘alloc’)), sel_getUid(‘init’));
{$ENDIF MACOS}
try
Thread.FStarted := True;
if not Thread.Terminated then
try
Thread.Execute;
except
Thread.FFatalException := AcquireExceptionObject;
end;
finally
Result := Thread.FReturnValue;
FreeThread := Thread.FFreeOnTerminate;
Thread.DoTerminate;
Thread.FFinished := True;
SignalSyncEvent;
if FreeThread then
begin
Thread.DisposeOf;
{$IFDEF AUTOREFCOUNT}
Thread.__ObjRelease; // This will clear the thread reference that was added by setting FreeOnTerminate.
{$ENDIF}
end;
{$IFDEF AUTOREFCOUNT}
Thread.__ObjRelease; // This will clear the thread reference we added above. This may initiate disposal.
{$ENDIF}
{$IFDEF USE_LIBICU}
// Destroy Collator Cache
ClearCollatorCache;
{$ENDIF}
{$IF Defined(MSWINDOWS)}
EndThread(Result);
{$ELSEIF Defined(POSIX)}
{$IFDEF MACOS}
// Last thing to do in thread is to drain the pool
objc_msgSend(pool, sel_getUid(‘drain’));
{$ENDIF MACOS}
{$IFDEF ANDROID}
// Detach the NativeActivity virtual machine to ensure the proper relase of JNI context attached to the current thread
PJavaVM(System.JavaMachine)^.DetachCurrentThread(PJavaVM(System.JavaMachine));
{$ENDIF ANDROID}
// Directly call pthread_exit since EndThread will detach the thread causing
// the pthread_join in TThread.WaitFor to fail. Also, make sure the EndThreadProc
// is called just like EndThread would do. EndThreadProc should not return
// and call pthread_exit itself.
if Assigned(EndThreadProc) then
EndThreadProc(Result);
pthread_exit(Result);
{$ENDIF POSIX}
end;
end;

is it a normal behavior ? if yes, i m the only one to think that arc is the worse think of delphi ?