SetTimer定时的分辨率最小到50ms,在需要更小的定时间隔时他就无能为力了，多媒体定时器在精确定实时中很有用处，能够定时到一毫秒，不过得到这样的好处是要付出代价的，使用起来略嫌麻烦，下面1-6步就是使用方法，不对之处请指正。原来写时使用了使用了英文注释，比较简单就不改了。
1.Link winmm.lib
＃i nclude <mmsystem.h>
#pragma comment(lib, "winmm.lib")
2.Define variables
#define TARGET_RESOLUTION 1 // 1-millisecond target resolution
int wTimerID; // store timer ID
int msInterval; // delay
UINT wTimerRes; // end resolution
3.Obtaining and setting timer resolution
//Obtaining timer resolution
TIMECAPS tc;
if (timeGetDevCaps(&tc, sizeof(TIMECAPS)) != TIMERR_NOERROR)
{
MessageBox("Obtaining timer resolution error");
return;
}
wTimerRes = min(max(tc.wPeriodMin, TARGET_RESOLUTION), tc.wPeriodMax);
//setting timer resolution
timeBeginPeriod(wTimerRes);
4.Starting a Single/Periodic Timer Event
wTimerID=timeSetEvent(
msInterval, // delay
wTimerRes, // resolution
MMTimerProc, // callback function
(DWORD)UserData,// User Data, it is sent to dwUser of the callback function //parameter
TIME_PERIODIC // TIME_PERIODIC or TIME_ONESHOT
);
5.Writing a Timer Callback Function
void CALLBACK MMTimerProc(UINT wTimerID, UINT msg,
DWORD dwUser, DWORD dw1, DWORD dw2)
{
//timer routine
}
6.Canceling a Timer Event
if(wTimerID) // is timer event pending?
{
timeKillEvent(npSeq->wTimerID); // cancel the event
wTimerID = 0;
}
7.Error Shoting
1.DWORD dwUserData = (DWORD)this; //UserData
//if it is used in global area will get the following error
error C2355: 'this' : can only be referenced inside non-static member functions
2. int msInterval;
msInterval = 1;
//if it is used in global area will get the following error
error C2501: 'msInterval' : missing storage-class or type specifiers
error C2374: 'msInterval' : redefinition; multiple initialization
8.Unserstanding Difficult Points
1. wTimerRes = min(max(tc.wPeriodMin, TARGET_RESOLUTION), tc.wPeriodMax);
