计时器是程序中最常用的后台任务机制之一，其时间间隔最低约为55毫秒，被广泛用于时钟、磁盘备份程序或需要在某一时刻运行的程序等。在Windows API中有很多查询时钟的函数，利用它们就可以编写出高精度的计时器。-timer procedure is the most commonly used mechanism for the background, one of the minimum time interval of about 55 milliseconds, are widely used in clocks, disk backup procedures or in a moment of the operation procedures. The Windows API is a lot of inquiries clock function, they can be used to prepare high-precision timer.