On Wed, Jul 11, 2018 at 1:34 PM Andrei Rybak <rybak.a.v@xxxxxxxxx> wrote: > > > + int human_tz = -1; > > Is -1 an OK initial value for timezone if local_time_tzoffset returns > negative values as well? It looks like it doesn't matter for from functional The value was intentionally picked to *not* be a valid timezone value, so that the comparison of "human_tz == tz" would always fail if DATE_HUMAN is not selected. But it could be anything else invalid, of course. It could be MAX_INT or something like that. By picking something that isn't possibly a real timezone value, late code can do things like hide.tz = local || tz == human_tz; without worrying about whther it's really DATE_HUMAN or not. The clearing of "human_tm" is done for a similar reason: the code does hide.year = tm->tm_year == human_tm->tm_year; (and then later just checks "if (human_tm->tm_year)") knowing that a non-zero tm_year will only ever happen for human_tz (and that 1900 is not a valid git date, even though I guess in theory you could do it). Linus