signal的samplecode

一个signal的samplecode, 需要注意的地方是：

1. 资源的释放和析构
2. 锁的控制
3. 资源的清理
4. 事务的控制

 

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/* This is signal handler common code */ #include <stdio.h> #include <stdlib.h> #include <unistd.h>   #include <iostream> #include <vector> #include <atomic> #include <csignal> #include <thread>   volatile std::atomic_bool g_bExitFlag{false}; volatile std::atomic_bool g_bInitFlag{false};   constexpr uint8_t kNumOfThreads = 5; std::vector<std::thread> gThreads;   void SignalHandlerThread(void) {     int sig = -1;     sigset_t sigset;       if (sigemptyset(&sigset) != 0) {         /* empty the set of signals */         printf("Emptying signal set failed.");         return;     }       if (sigaddset(&sigset, SIGTERM) != 0) {         /* add SIGTERM to signal set */         printf("Adding SIGTERM to signal set failed.");         return;     }       if (sigaddset(&sigset, SIGINT) != 0) {         /* add SIGINT to signal set */         printf("Adding SIGINT to signal set failed.");         return;     }       /* wait until signal SIGTERM/SIGINT occurs */     while (sig != SIGTERM && sig != SIGINT) {         if (0 != sigwait(&sigset, &sig)) {             printf("Sigwait() was called with an invalid signal set.");             return;         }     }       printf("SignalHandler get the signal(%d)\n", sig);     g_bExitFlag = true; }   int SetSignalMask() {     bool success = true;     sigset_t signals;       /* Block all signals except SIGABRT, SIGBUS, SIGFPE, SIGILL and SIGSEGV */     success = success && (sigfillset(&signals) == 0);     success = success && (sigdelset(&signals, SIGABRT) == 0);     success = success && (sigdelset(&signals, SIGBUS) == 0);     success = success && (sigdelset(&signals, SIGFPE) == 0);     success = success && (sigdelset(&signals, SIGILL)) == 0;     success = success && (sigdelset(&signals, SIGSEGV) == 0);     success = success && (pthread_sigmask(SIG_SETMASK, &signals, nullptr) == 0);     if (!success) {         printf("SetSignalMask failed. \n");         return -1;     }       return 0; }   int Init() {     /* initialize signal handling */     SetSignalMask();       /* spawn a new signal handler thread */     gThreads.push_back(std::thread(SignalHandlerThread));     g_bInitFlag = true;           //printf("tid thtread id    :%lu. \n", gThreads.begin()->get_id());     printf("tid native handle :%lu. \n", static_cast<pthread_t>(gThreads.begin()->native_handle()));       return 0; }   void Shutdown() {     /* check state */     /* clean-up */     /* kill/cancel pthread */       /* wait pthread */     printf("Waitfor the threads.\n");     for (std::vector<std::thread>::iterator it = gThreads.begin();             it != gThreads.end(); it++) {         it->join();     }       std::cout << "Terminating." << std::endl; }   int Run() {     Init();     while (!g_bExitFlag) {         /* Todo:work thread */     }       Shutdown();     return 0; }   int main() {     try {         Run();     } catch (std::runtime_error& e) {         std::cout << "Runtime error: " << e.what();     } catch (std::logic_error& e) {         std::cout << "Logic error: "<< e.what();     } catch (std::exception& e) {         std::cout << "Exception: "<< e.what();     } catch (...) {         std::cout << "Unknown exception";     }       return 0; }

　

/* like pause() */
void HandleSignals()  {
  sigset_t sigset;
  int signal = 0;
  bool done = false;

  ::sigemptyset(&sigset);
  ::sigaddset(&sigset, SIGTERM);
  ::sigaddset(&sigset, SIGINT);
while (!done) {
    timespec timeout;
    timeout.tv_sec = 1;
    timeout.tv_nsec = 0;
    signal = ::sigtimedwait(&sigset, NULL, &timeout);

    switch (signal) {
      case SIGINT:
        printf("call signal SIGINT");
        done = true;
        break;
      case SIGTERM:
        printf("call signal SIGTERM");
        done = true;
        break;
    }
  }
}