多线程 Semaphore 回调函数 多媒体定时器的使用

//

//作用：WIN32API创建两个线程各自定时输出tickcount

//

//

// timerSemaphore.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "windows.h"
#include "mmsystem.h"
#pragma comment (lib,"winmm.lib")

#define ONE_MILLI_SECOND 1 //定义1ms和2s时钟间隔，以ms为单位 ；
#define TWO_SECOND 2000
#define TIMER_ACCURACY 1 //定义时钟分辨率，以ms为单位

HANDLE hEventOnTimer;

void CALLBACK TimerCallback(UINT wTimerID,UINT msg,DWORD dwUser,DWORD dw1,DWORD dw2)
{
 ::SetEvent(hEventOnTimer);
 printf("timer callback! at tick: %d\n",::GetTickCount());
}

void ThreadProc()  
{
 while(1)
 {
// ::ResetEvent(hEventOnTimer);
 ::WaitForSingleObject(hEventOnTimer,INFINITE);      // 经过测试，没有与callback函数之间没有延时
 printf("timer callback in Thread Proc! at tick: %d\n",::GetTickCount());
 }

}

int main()
{
 UINT TimerID_1ms;
 TIMECAPS tc;
 DWORD ThreadID;
 hEventOnTimer=::CreateEvent(NULL,false,false,NULL);  //关键！！！

 //利用函数timeGetDeVCaps取出系统分辨率的取值范围，如果无错则继续；
 if(timeGetDevCaps(&tc,sizeof(TIMECAPS))==TIMERR_NOERROR)
 { UINT wAccuracy=min(max(tc.wPeriodMin,TIMER_ACCURACY),tc.wPeriodMax);
 //调用timeBeginPeriod函数设置定时器的分辨率
 ::timeBeginPeriod(wAccuracy);
 }
// ::ResetEvent(hEventOnTimer);
 if ((TimerID_1ms=timeSetEvent(30,1,(LPTIMECALLBACK)TimerCallback,0,TIME_PERIODIC))==0)
 {
  printf("cannot set timer!\n");
 };
 ::CreateThread(NULL,0,(LPTHREAD_START_ROUTINE)ThreadProc,&TimerID_1ms,0,&ThreadID);
 getchar();
 return 1;
}