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  1. #include <iostream>
  2. #include <atomic>
  3. #include <thread>
  4. #include <mutex>
  5. #include <condition_variable>
  6. #include <chrono>
  7.  
  8. using namespace std;
  9.  
  10.  
  11. class EventWaitHandle {
  12.  
  13. public:
  14.     EventWaitHandle(bool handleWillCloseAfterOneWait, bool openAtStart)
  15.         : autoReset(handleWillCloseAfterOneWait), handleOpen(openAtStart)
  16.     { }
  17.  
  18.     void set() {
  19.         {
  20.             std::lock_guard<std::mutex> handleOpenLock(handleOpenLocker);
  21.             handleOpen = true;
  22.         }
  23.  
  24.         handleOpenSignal.notify_one();
  25.     }
  26.  
  27.     void reset() {
  28.         {
  29.             std::lock_guard<std::mutex> handleOpenLock(handleOpenLocker);
  30.             handleOpen = false;
  31.         }
  32.  
  33.         handleOpenSignal.notify_one();
  34.     }
  35.  
  36.     bool wait(int millisecondsBeforeTimeout) {
  37.         {
  38.             std::lock_guard<std::mutex> handleOpenLock(handleOpenLocker);
  39.  
  40.             if (handleOpen) {
  41.                 handleOpen = !autoReset;
  42.                 return true;
  43.             }
  44.  
  45.             if (millisecondsBeforeTimeout < 1) // Handle isn't open and we are waiting no time, punt..
  46.                 return false;
  47.  
  48.         }
  49.  
  50.         auto start = std::chrono::system_clock::now();
  51.         cout << "waiting.." << endl;
  52.         std::unique_lock<std::mutex> lockJustForThisWaiter(handleOpenLocker);
  53.  
  54.         if(handleOpenSignal.wait_until(lockJustForThisWaiter, start + std::chrono::milliseconds(millisecondsBeforeTimeout)) == std::cv_status::timeout)
  55.             return false;
  56.  
  57.         auto timeLeftToWaitInEventOfSpuriousness = std::chrono::milliseconds(millisecondsBeforeTimeout) - (std::chrono::system_clock::now() - start);
  58.         int millisecondsLeftToWait = 0;
  59.         millisecondsLeftToWait = std::chrono::duration_cast<std::chrono::milliseconds>(timeLeftToWaitInEventOfSpuriousness).count();
  60.  
  61.         return wait(millisecondsLeftToWait);
  62.     }
  63.  
  64. private:
  65.  
  66.     bool autoReset;
  67.  
  68.     std::condition_variable handleOpenSignal;
  69.     std::atomic<bool> handleOpen;
  70.     std::mutex handleOpenLocker;
  71. };
  72.  
  73.  
  74. int main() {
  75.     EventWaitHandle waitHandle(true, true);
  76.  
  77.     bool open;
  78.  
  79.     open = waitHandle.wait(100);
  80.     if (open)
  81.         cout << "open" << endl;
  82.     else
  83.         cout << "not open" << endl;
  84.  
  85.     waitHandle.set();
  86.  
  87.     open = waitHandle.wait(100);
  88.     if (open)
  89.         cout << "open" << endl;
  90.     else
  91.         cout << "not open" << endl;
  92.  
  93.     waitHandle.reset();
  94.  
  95.     open = waitHandle.wait(100);
  96.     if (open)
  97.         cout << "open" << endl;
  98.     else
  99.         cout << "not open" << endl;
  100.  
  101.     return 0;
  102. }
Success #stdin #stdout 0s 3416KB
comments (?)
stdin
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Standard input is empty
stdout
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open
open
waiting..
not open
https://ideone.com/sIdC5A
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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