Windows中的计时器(SetTimer和CreateWaitableTimer)
Timers (SetTimer and CreateWaitableTimer) in Windows
1.SetTimer
下面的例子创建了一个计时器(不与窗口相关联)，该计时器过程函数建了20个消息框。
The following example creates a timer (that is not attached to a window) whose Timer Procedure creates 20 Message Boxes
#include <windows.h>
class foo_class {
static int counter;
public:
//static函数，相当于全局
static void __stdcall timer_proc(HWND,unsigned int, unsigned int, unsigned long) {
if (counter++ < 20)
MessageBox(0,"Hello","MessageBox",0);
else
PostQuitMessage(0);
}
};
int foo_class::counter=0;
WINAPI WinMain(HINSTANCE,HINSTANCE,LPSTR,int) {
//第1个参数，MSDN中指出如果置为NULL，即0,不与窗口相关联。
//If this parameter is NULL, no window is associated with the timer and the nIDEvent parameter is ignored.
//第2个参数会被忽略
//第3个参数，300毫秒触发一次
//第4个参数，触发时由函数foo_class::timer_proc响应
int iTimerID = SetTimer(0, 0, 300, foo_class::timer_proc);
MSG m;
//这是消息循环
while (GetMessage(&m,0,0,0)) {
TranslateMessage(&m);
DispatchMessage(&m);
}
return 1;
}
2.CreateWaitableTimer
这个例子演示如何在windows中使用计时器。
计时器被设计为(1)在第1次调用CreateWaitableTimer后2秒触发，(2)此后每3/4秒触发一次。
#define _WIN32_WINNT 0x0400
#include <windows.h>
#include <process.h>
#include <stdio.h>
unsigned __stdcall TF(void* arg) {
HANDLE timer=(HANDLE) arg;
while (1) {
//此处，进程间通信的接收方
//timer是命名的，因此进程间或线程间没有区别
WaitForSingleObject(timer,INFINITE);
printf(".");
}
}
int main(int argc, char* argv[]) {
//创建，命名为0，也可以是LPCTSTR，字符串
//其他进程可以通过OpenWaitableTimer获得此timer的句柄，并对之进行SetWaitableTimer
HANDLE timer = CreateWaitableTimer(
0,
false, // false=>will be automatically reset
0); // name
LARGE_INTEGER li;
const int unitsPerSecond=10*1000*1000; // 100 nano seconds
// Set the event the first time 2 seconds
// after calling SetWaitableTimer
//2秒
li.QuadPart=-(2*unitsPerSecond);
//通过句柄设置timer
SetWaitableTimer(
timer,
&li,
750, // Set the event every 750 milli Seconds
0,
0,
false);
//用TF函数启动worker线程
_beginthreadex(0,0,TF,(void*) timer,0,0);
// Wait forever,
while (1) ;
return 0;
}
参考：
1.[http://www.adp-gmbh.ch/win/misc/timer.html ]
2.[http://support.microsoft.com/kb/184796]，中文的