if(fcntl(listen_fd, F_SETFL, O_NONBLOCK) < 0) {
logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));
if(fcntl(listen_fd, F_SETFL, O_NONBLOCK) < 0) {
logger(DEBUG_ALWAYS, LOG_ERR, "System call `%s' failed: %s", "fcntl", strerror(errno));