[boost thread interrupt]example of boost::thread interruption #interrupt #multithreading #boost

boost_thread_interrupt.cpp

#include <iostream>
#include <boost/chrono/chrono.hpp>
#include <boost/thread/thread.hpp>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/types.h>

static pid_t child_pid = 0;

void child_process_thread_func() {
  std::cout <<__func__ <<", hello..." <<std::endl;
  while (1) {
    try {
      boost::this_thread::sleep_for(boost::chrono::seconds(1));
      std::cout <<__func__<<", thread alive!" <<std::endl;
    } catch (boost::thread_interrupted&) {
      std::cout <<__func__ <<", thread terminated!" <<std::endl;
      return ;
    }
  }
}

void reclaim_child_process() {
  while (1) {
    pid_t reclaim_pid = waitpid(child_pid, nullptr, 0);
    if (reclaim_pid < 0) {
      if (ECHILD == errno) {
        std::cout <<__func__ <<", all child process terminated!" <<std::endl;
        break;
      } else {
        std::cout <<__func__ <<", waitpid failed, " <<strerror(errno) <<std::endl;
        continue;
      }
    }
    std::cout <<__func__ <<", pid: " <<reclaim_pid <<" terminated!" <<std::endl;
  }
}

int main(int argc, char **argv) {
  boost::thread  my_thread;
  pid_t pid = fork();
  switch (pid) {
    case 0: {
      child_pid = getpid();
      std::cout <<"child process! pid:" <<getpid() <<std::endl;
      my_thread = boost::thread(child_process_thread_func);

      /* if uncomment this line, my_thread will not interrupt until child process is going to die */
      // my_thread.detach();    
      break;
    }

    case -1: {
      std::cerr <<"fork failed, " <<strerror(errno) <<std::endl;
      break;
    }

    default: {
      child_pid = pid;
      std::cout <<"parent pid:" <<getpid() <<", child process id: " << pid <<std::endl;
      break;
    }
  }

  if (child_pid == getpid()) {
    boost::this_thread::sleep_for(boost::chrono::seconds(3));
    my_thread.interrupt();
    my_thread.join();
  } else {
    reclaim_child_process();
  }
	
  std::cout <<"pid: "<<getpid() <<" game over!" <<std::endl;
  return 0;
}