問題代碼:

 1 #include<windows.h>
 2 #include<iostream>
 3 #include<thread>
 4 HANDLE h1;
 5 HANDLE h2;
 6 
 7 void CALLBACK test(PVOID a, BOOLEAN b)
 8 {
 9     std::cout << "This a test function excuted by Thread:" << std::this_thread::get_id()<< std::endl;
10     //std::cout << "Here we try to delete timer in Thread:" << std::this_thread::get_id() << std::endl;
11     if (0 == DeleteTimerQueueTimer(NULL, h1, INVALID_HANDLE_VALUE))
12     {
13         std::cout << "Timer  Deleted Failed in Thread:" << std::this_thread::get_id() << std::endl;
14     }
15     std::cout << "Timer  Deleted Successfully in Thread:" << std::this_thread::get_id() << std::endl;
16 
17 }
18 void CALLBACK test1(PVOID l, BOOLEAN t)
19 {
20     std::cout << "This a test1 function excuted by Thread:" << std::this_thread::get_id() << std::endl;
21 }
22 
23 int main()
24 {
25     
26     std::cout << "******This is a Test for TimeQueueTimer in Windows API******" << std::endl;
27     std::cout << "Main thread is executed by thread: " << std::this_thread::get_id() << std::endl;
28     //test(PVOID(1), TRUE);
29     try
30     {
31         CreateTimerQueueTimer(&h1, NULL, WAITORTIMERCALLBACK(test), NULL, 0, 1000, WT_EXECUTEINTIMERTHREAD);
32         //Sleep(1000);
33 
34         CreateTimerQueueTimer(&h2, NULL, WAITORTIMERCALLBACK(test1), NULL, 0, 1000, WT_EXECUTEINTIMERTHREAD);
35 
36 
37         //CreateTimerQueueTimer(&h1, NULL, [](PVOID lpParameter, BOOLEAN TimerOrWaitFired) {
38         //    test(lpParameter, TimerOrWaitFired); // Call your original test function from within the lambda
39         //    }, NULL, 0, 1000, WT_EXECUTEINTIMERTHREAD);
40 
41     }
42     catch (const std::exception& e)
43     {
44         std::cout << "something error with the timer: " << e.what() << std::endl;
45     }
46 
47 
48     if (std::cin.get())
49     {
50         if (0 == DeleteTimerQueueTimer(NULL, h2, INVALID_HANDLE_VALUE))
51         {
52             std::cout << "Timer  Deleted Failed in Thread:" << std::this_thread::get_id() << std::endl;
53         }
54         std::cout << "Timer  Deleted Successfully in Thread:" << std::this_thread::get_id() << std::endl;
55 
56     };
57     Sleep(1000);
58 
59     return 0;
60 }

Main()函數中test1回調無法執行！

問題分析：

CreateTimerQueueTimer和DeleteTimerQueueTimer 分別負責線程的開啟和中止，函數定義如下：

BOOL CreateTimerQueueTimer(
  [out]          PHANDLE             phNewTimer,
  [in, optional] HANDLE              TimerQueue,
  [in]           WAITORTIMERCALLBACK Callback,
  [in, optional] PVOID               Parameter,
  [in]           DWORD               DueTime,
  [in]           DWORD               Period,
  [in]           ULONG               Flags
);

BOOL DeleteTimerQueueTimer(
  [in, optional] HANDLE TimerQueue,
  [in]           HANDLE Timer,
  [in, optional] HANDLE CompletionEvent
);

主線程中分別利用CreateTimerQueueTimer開啟後臺線程調用回調test()和test1(),併在test()調用中結束調用。由於DeleteTimerQueueTimer中CompletionEvent中使用的是INVALID_HANDLE_VALUE，導致線程會等待所有timer線程執行結束，才能返回。而當前執行回調的線程等不到自己結束，陷入死鎖。因為CreateTimerQueueTimer的Flag參數使用的是WT_EXECUTEINTIMERTHREAD，導致test1回調和test使用的是同一線程，而test線程已經死鎖，所以test1也無法得到執行

解決方案：

1. 不應該在回調中調用DeleteTimerQueueTimer中止線程
2. 如果必須在回調中中止線程，CompletionEvent應設為NULL，標記當前線程結束後，直接返回0（執行失敗），回調執行完，不再繼續執行
3. CreateTimerQueueTimer使用Flag WT_EXECUTEDEFAULT開啟新線程，即使上一個timer線程死鎖，第二個線程仍可以執行

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