delphi GetMem使用

procedure TForm12.Button2Click(Sender: TObject);

var

  mystring: PChar;

begin

  GetMem(mystring, 1024);

  GetWindowText(Button1.Handle,mystring,100);

  Label1.Caption := Format('%s:%d', [mystring, strlen(mystring)]);

  FreeMem(mystring);

end;