Threads in VST

[Dzyszla]

Threads in VST

[joachimmarder]

What exactly make you think that the thread of Virtual TreeView causes the crash?

[Dzyszla]

I attach demo code (two projects: exe and dll):
VST_Test.zip

On my computer have no errors, but when I run it on Windows 2012/2016/2019 Server, click button and close window (by shortcut, by mouse click - no matter) in 1 on 10 times crash (but sometime can be 10 times without error, and next every 3 run and close ends with crash).
here attach system logs:
VSTerrors.zip

[Dzyszla]

PS - When I made changes in dispose method, then works good:

class procedure TWorkerThread.Dispose(CanBlock: Boolean);
var
  LRef: TThread;
begin
  WorkerThread.FreeOnTerminate := False;   // << NEVR USE FREE ON TERMINATE
  //WorkerThread.FreeOnTerminate := not CanBlock;  // << -- " --
  WorkerThread.Terminate();
  SetEvent(WorkerThread.FWorkEvent);
  LRef := WorkerThread;
  WorkerThread.WaitFor; // << ADD WAITING  FOR TERMINATE
  WorkerThread := nil; //Will be freed usinf TThread.FreeOnTerminate
  //if CanBlock then   << DISABLE THIS LINE - OBJECT MUST BE ALWAYS FREE
	LRef.Free;
end;

[joachimmarder]

I didn't get a single crash in 30 tries with your demo project.

Can you please check if the following change makes any difference in your case: In TBaseVirtualTree.Destroy() change the call to TWorkerThread.ReleaseThreadReference to:

TWorkerThread.ReleaseThreadReference(IsLibrary);

[Dzyszla]

I try my demo on my own system, and it's crash after about 1 on 60-80 trials (very infrequently, but possible). I think, it depends on cpu cores load.

I made the changes as suggested (and I rolled back my own previous changes) and looks all right - no more crashes.