• arc@lemm.ee
    link
    fedilink
    arrow-up
    5
    ·
    edit-2
    7 months ago

    UTC always goes forward regardless of the timezone and local time. That is why you should use it. To take my EPG situation above, I stored program start / end times in UTC so they would render properly even if DST kicked in or not during the middle of the program.

    • uis@lemm.ee
      link
      fedilink
      arrow-up
      2
      ·
      edit-2
      7 months ago

      Ok, this is more unix time quirk that can’t handle 24:00:00 and skipping 23:59:59.

      UTC always goes forward regardless of the timezone and local time

      But not unix time.

      I stored program start / end times in UTC

      If your program finishes in less than one seond it might report negative time.

      • arc@lemm.ee
        link
        fedilink
        arrow-up
        4
        ·
        7 months ago

        I didn’t say Unix time, I said UTC. And no it won’t report negative time, not unless somehow the system clock was modified while it was running…

        • uis@lemm.ee
          link
          fedilink
          arrow-up
          1
          ·
          edit-2
          7 months ago

          not unless somehow the system clock was modified while it was running…

          Which is how most systems handle leap seconds.

          • arc@lemm.ee
            link
            fedilink
            arrow-up
            1
            ·
            edit-2
            7 months ago

            Leap seconds still make time go forwards, not backwards. NTP clients would also resolve small time discrepancies while still advancing forwards prior to the next time sync.

            • uis@lemm.ee
              link
              fedilink
              arrow-up
              1
              ·
              edit-2
              7 months ago

              Leap seconds can make time go both ways, but adding them makes time stop/go back because 24:00:00 cannot be represented as 1/86400 part of day N instead of day N+1 on major OSes. And they were only added so far.

              • arc@lemm.ee
                link
                fedilink
                arrow-up
                1
                ·
                edit-2
                7 months ago

                It doesn’t work like that. UTC goes forward always. Leap seconds are scheduled and known in advance. NTP time services will just smear time advancement a little to account for an additional second. Time never has to go backwards. This is how Google does it.

                • uis@lemm.ee
                  link
                  fedilink
                  arrow-up
                  1
                  ·
                  7 months ago

                  This is how Google does it in their datacenters, but not major OSes by default