update_thread
if ((err = pthread_create(NULL, NULL, update_thread, NULL)) != 0) {
if ((err = pthread_create(NULL, NULL, update_thread, NULL)) != 0) {
if ((err = pthread_create(NULL, NULL, update_thread, NULL)) != 0) {
if (0 != thr_create(NULL, NULL, update_thread, new_map,
void * update_thread(void *);