WinAPI: QueryPerformanceCounter - 获取高性能定时器的当前值

//声明:

QueryPerformanceCounter(

  var lpPerformanceCount: TLargeInteger {获取定时器每秒的频率数; TLargeInteger = Int64}

): BOOL; {返回 False 表示调用失败, 或者是硬件不支持高性能定时器}


 
   




//一个有趣的示例: 判断你的鼠标点击速度; 我的最快记录是 151 毫米

var

  n1,n2,n,f: Int64;

  b: Boolean;



procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;

  Shift: TShiftState; X, Y: Integer);

begin

  n := 0;

  b := not b;

  if b then QueryPerformanceCounter(n1) else begin

    QueryPerformanceCounter(n2);

    n := n2 - n1;

  end;



  if n<>0 then

  begin

    QueryPerformanceFrequency(f);

    n := n*1000 div f;

    Text := IntToStr(n) + ' ms';

  end else Text := '等待第二下...';

end;