请问引用型参数如何定义？

Question

procedure TForm1.test(str:string);   <--------这里如何定义成引用类型的
begin
        str:='123';
end;
procedure TForm1.BitBtn1Click(Sender: TObject);
var
  v1:string;
begin        test(v1);        Edit1.Text:=v1;
end;

Answer 1

like this:
procedure test(var str:string);

Answer 2

procedure TForm1.test(var str:string); 
begin
        str:='123';
end;
procedure TForm1.BitBtn1Click(Sender: TObject);
var
  v1:string;
begin        test(v1);        Edit1.Text:=v1;
end;