Using Timer Queues

最新推荐文章于 2024-07-29 10:14:35 发布

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文章标签：

#timer #thread #null #object #function #callback

本文介绍了一个使用Windows API创建定时器队列的例子。通过CreateEvent、CreateTimerQueue和CreateTimerQueueTimer等函数，设置了一个延迟10秒后执行的定时器例程。此外，还演示了如何使用WaitForSingleObject来等待定时器线程完成。

Using Timer Queues (Windows)

Using Timer Queues

The following example creates a timer routine that will be executed by a thread from a timer queue after a 10 second delay. First, the code uses the CreateEvent function to create an event object that is signaled when the timer-queue thread completes. Then it creates a timer queue and a timer-queue timer, using the CreateTimerQueue and CreateTimerQueueTimer functions, respectively. The code uses the WaitForSingleObject function to determine when the timer routine has completed. Finally, the code calls DeleteTimerQueue to clean up.

For more information on the timer routine, see WaitOrTimerCallback.
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#include
#include

HANDLE gDoneEvent;

VOID CALLBACK TimerRoutine(PVOID lpParam, BOOLEAN TimerOrWaitFired)
{
if (lpParam == NULL)
{
printf("TimerRoutine lpParam is NULL/n");
}
else
{
// lpParam points to the argument; in this case it is an int

printf("Timer routine called. Parameter is %d./n",
*(int*)lpParam);
if(TimerOrWaitFired)
{
printf("The wait timed out./n");
}
else
{
printf("The wait event was signaled./n");
}
}

SetEvent(gDoneEvent);
}

int main()
{
HANDLE hTimer = NULL;
HANDLE hTimerQueue = NULL;
int arg = 123;

// Use an event object to track the TimerRoutine execution
gDoneEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
if (NULL == gDoneEvent)
{
printf("CreateEvent failed (%d)/n", GetLastError());
return 1;
}

// Create the timer queue.
hTimerQueue = CreateTimerQueue();
if (NULL == hTimerQueue)
{
printf("CreateTimerQueue failed (%d)/n", GetLastError());
return 2;
}

// Set a timer to call the timer routine in 10 seconds.
if (!CreateTimerQueueTimer( &hTimer, hTimerQueue,
(WAITORTIMERCALLBACK)TimerRoutine, &arg , 10000, 0, 0))
{
printf("CreateTimerQueueTimer failed (%d)/n", GetLastError());
return 3;
}

// TODO: Do other useful work here

printf("Call timer routine in 10 seconds.../n");

// Wait for the timer-queue thread to complete using an event
// object. The thread will signal the event at that time.

if (WaitForSingleObject(gDoneEvent, INFINITE) != WAIT_OBJECT_0)
printf("WaitForSingleObject failed (%d)/n", GetLastError());

CloseHandle(gDoneEvent);

// Delete all timers in the timer queue.
if (!DeleteTimerQueue(hTimerQueue))
printf("DeleteTimerQueue failed (%d)/n", GetLastError());

return 0;
}