return timezone == 0 && daylight == 0;
}
+
+int time_change_fd(void) {
+
+ /* We only care for the cancellation event, hence we set the timeout to the latest possible value. */
+ static const struct itimerspec its = {
+ .it_value.tv_sec = TIME_T_MAX,
+ };
+
+ _cleanup_close_ int fd;
+
+ assert_cc(sizeof(time_t) == sizeof(TIME_T_MAX));
+
+ /* Uses TFD_TIMER_CANCEL_ON_SET to get notifications whenever CLOCK_REALTIME makes a jump relative to
+ * CLOCK_MONOTONIC. */
+
+ fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC);
+ if (fd < 0)
+ return -errno;
+
+ if (timerfd_settime(fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0)
+ return -errno;
+
+ return TAKE_FD(fd);
+}