Logfile is cleared when restart the app

[Christophe Ravaut]

I have tried TLogFileAppender and noticed that between app restarts the logfile is cleared and did not notice any property / method that would change this behaviour.

[Christophe Ravaut]

I must use TStreamLogAppender and set the position of the TFileStream to the size.

procedure TForm1.FormCreate(Sender: TObject);
var
  s: TFileStream;
  oAppender: TFileLogAppender;

begin

  s := TFileStream.Create('U:\Development\Projects\Testing\Test_logging\Win32\Debug\Logger.txt', fmOpenReadWrite or fmShareDenyNone);
  s.Position := s.Size;

  fAppender := TStreamLogAppender.Create(s);

  fController := TLoggerController.Create();
  fController.AddAppender(fAppender);
  fLogger := TLogger.Create(fController);

end;

[Stefan Glienke]

I would suggest using:

System.IOUtils.TFile.Open(path, TFileMode.fmAppend, TFileAccess.faReadWrite, TFileShare.fsReadWrite);

That handles everything perfectly - yours would now fail when the file does not exist yet. And it automatically sets the position to the end.

[Christophe Ravaut]

I was catching the problem with FileExist but your suggestion is the best. And I've learn something again. Nice.