Lazarus/Delphi – writing to text file without overwriting next time

Question

I’m using Lazarus and I wanted to save information to a text when the program terminates. But each time I reopen the program it overwrites what was there before in the text file. It would be OK to append a new line to the file or even create a different text file each time. This is what I have:

var
  // … other variable declarations omitted …
  s: TStringList;
begin
  s:= TStringList.Create;
  s.Add(datetostr(now));
  s.SaveToFile(datetostr(now)+'.txt');
  s.Free;

But it gives me an error.

Answer 1

All you need to do is open your file in append mode, and then add your text. It will put the new data at the end of the file:

  AssignFile(tfOut, C_FNAME);

  try
    // Open for append, write and close.
    append(tfOut);

    writeln(tfOut, 'New data for text file');
    writeln(tfOut, 'New informtion should be at the end of the file.');

    CloseFile(tfOut);

  except
    on E: EInOutError do
     writeln('File error. Elaboration: ', E.Message);
  end;