clock_gettime(CLOCK_REALTIME, &tp1);
clock_gettime(CLOCK_REALTIME, &tp2);
if (tp1.tv_sec != tp2.tv_sec || tp1.tv_nsec != tp2.tv_nsec)
clock_gettime(CLOCK_REALTIME, &tp1);
clock_gettime(CLOCK_REALTIME, &tp2);
if (tp1.tv_sec != tp2.tv_sec || tp1.tv_nsec != tp2.tv_nsec)