delphi lazarus copy

procedure TRtlForm.Button1Click(Sender: TObject);
var
  s1,s2:String;
begin

s1:='1234567';
//从第3个开始拷贝10个字符，超过字符长度全拷贝
s2:=Copy(s1,3,10);
ShowMessage(s2);
end;