C++非阻塞式延时函数XSleep

//Function:XSleep()//Purpose:Tomaketheapplicationsleepforthespecifiedtime//duration.//DurationtheentiretimedurationXSleepsleeps,it//keepsprocessingthemessagepump,toensurethatall//messagesarepostedandthatthecallingthreaddoes//notappeartoblockallthreads!