Question

I’m writing a small program to save in a file the content of a TEdit control.

The idea is that user write something in a TEdit control and then push button to write file on disk, but when try to compile I got “unit1.pas(37,15) Error: Wrong number of parameters specified for call to “Close” “

My form only have the TEdit control and a TButton.

var
  Form1: TForm1;
  f: text;

procedure TForm1.Button1Click(Sender: TObject);
begin
     writeln (f,Edit1.Text);
     close (f);
end;

Begin
     assign (f,'code.txt');
     rewrite (f);
end.

What the hell I’m doing wrong???

Answer 1

With a little googling I found this

Close exists in both System unit (implicitly used) and TCustomForm (TForm ancestor) class. Pascal identifier scoping rules makes unqualified Close takes the inner most scope. Therefore, if you call it in a TForm method, then it’s TForm’s Close that gets called. To avoid this, either use qualified call (System.Close to call the one from System unit or Self.Close to call the one belonging to current form) or CloseFile (which actually just calls System.Close) from ObjPas unit (automatically used in {$mode objfpc} or {$mode delphi}).