mainloop_add
extern int mainloop_add(int fd, mainloop_callback_t cb, void *data);
if (mainloop_add(thermal_events_fd(td.th), thermal_event, &td)) {
if (mainloop_add(thermometer->tz[i].fd_timer,
if (mainloop_add(fd, pid < 0 ? exit_mainloop : kill_process, &pid)) {
if (mainloop_add(fd, exit_mainloop, NULL)) {