diff_timespec
diff_timespec(&rs, &ts, &ref_time);
diff_timespec(&time_diff, time_stop, time_start);
delta1 = diff_timespec(mon_start, mon_end);
delta2 = diff_timespec(raw_start, raw_end);
newdiff = diff_timespec(start, end);
delay = diff_timespec(&ts3, &ts1);
sample->offset = diff_timespec(&ts2, &ts1);
delta1 = diff_timespec(mon, raw);
delta2 = diff_timespec(mon, raw);
interval = diff_timespec(start, end);
newdiff = diff_timespec(start, end);