void* threadFunc(void* thread_data)  {
  string domain = *(string *)thread_data;
  syslog(LOG_INFO, "Info: domain in = %s", domain.c_str());
  struct hostent *he;
  struct in_addr **addr_list;
  syslog(LOG_INFO, "Info: domain search information");
  if((he = gethostbyname(domain.c_str())) == NULL)
    syslog(LOG_NOTICE, "Notice: Not found IP addresses for host - \"%s\"", domain.c_str());
  else  {
    addr_list = (struct in_addr **)he->h_addr_list;
    for(int j = 0; addr_list[j] != NULL; j++)
      syslog(LOG_INFO, "Info: Found IP address \"%s\" for host - \"%s\"", inet_ntoa(*addr_list[j]), domain.c_str());
  }
  syslog(LOG_INFO, "Info: domain write information");
  pthread_exit(NULL);
  return NULL;
}

int find_ip2(vector<string> domains)  {
  int n = domains.size();
  pthread_t threads[n];

  syslog(LOG_INFO, "Info: count domains = %d", n);

  for(int j = 1, i = 0; j < n ; j++, i++)  {
     syslog(LOG_INFO, "Info: %d. domain = %s", j, domains[j].c_str());
     syslog(LOG_INFO, "Info: %d. count domains = %d", j, n);
     syslog(LOG_INFO, "Info: %d. domain send = %s", j, domains[j].c_str());
     syslog(LOG_INFO, "Info: %d. domain %d -> set = %s", j, (i + 1), domains[j].c_str());
     pthread_create(&threads[i], &tattr, threadFunc, &domains[j]);
  }

  syslog(LOG_INFO, "Info: start clearing thread!");

  for(int t = 0 ; t < n ; t++)  {
    syslog(LOG_INFO, "Info: threads[%d] join(%d joins)!", t, n);
    pthread_join(threads[t], NULL);
  }

  syslog(LOG_INFO, "Info: domain finish search ips.");

  return n;
}

cat /proc/sys/kernel/threads-max
64523