time limit

#if defined(WIN32) && ! defined(USE_GENERIC)
# define USE_GENERIC
#endif

#ifdef USE_GENERIC
# include <thread>
  // using std::thread, std::this_thread
# include <chrono>
  // using std::chrono::seconds
# include <csignal>
  // using std::raise, SIGABRT, SIGXCPU
#else
# include <sys/time.h>
# include <sys/resource.h>
  // using setrlimit
# include <algorithm>
  // using std::min
# include <system_error>
  // using std::system_error, std::system_category
# include <cerrno>
  // using errno
#endif


namespace ext {

#ifdef USE_GENERIC

  namespace {
    void sleeper_thread(int seconds)
    {
      std::this_thread::sleep_for(std::chrono::seconds(seconds));
      int signal;
#    ifdef SIGXCPU
      signal = SIGXCPU;
#    else
      signal = SIGABRT;
#    endif
      std::raise(signal);
    }
  }

  void limit_time(int seconds)
  {
    std::thread(sleeper_thread, seconds).detach();
  }

#else

  void limit_time(int seconds)
  {
    rlimit limit;
    if(getrlimit(RLIMIT_CPU, &limit))
      goto err;
    if(limit.rlim_max > static_cast<rlim_t>(seconds))
      limit.rlim_max = seconds;
    limit.rlim_cur = limit.rlim_max;
    if(setrlimit(RLIMIT_CPU, &limit))
      goto err;
    return;
  err:
    throw std::system_error(errno, std::system_category(), "rlimit");
  }

#endif

}

int main()
{
  ext::limit_time(10);

  int j = 1;
  for(unsigned i = 10; i >= 0; --i) // accidental infinite loop
    j *= 2;
  return j;
}