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Re^3: Logical ways to calculate being within two times (leaps)

by tye (Sage)
on Nov 28, 2016 at 21:26 UTC ( #1176740=note: print w/replies, xml ) Need Help??


in reply to Re^2: Logical ways to calculate being within two times
in thread Logical ways to calculate being within two times

My experience says that leap seconds do not impact epoch time (note that after inserting 26 leap seconds, the epoch time at the top of a minute is still currently a multiple of 60, whether using UTC or not). And, when you think about it, they can't.

Leap seconds are not scheduled very far in advance but epoch times for years in the future have been being used for years in the past. So leap seconds can't impact (Unix-style) epoch time values else past calculations of future dates would become inaccurate.

- tye        

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Re^4: Logical ways to calculate being within two times (leaps)
by BrowserUk (Pope) on Nov 28, 2016 at 21:37 UTC
    My experience says that leap seconds do not impact epoch time ... And, when you think about it, they can't.

    You missed the point. I was not describing a problem with epoch times per se; but rather my method of deriving them.

    The loop relies upon hitting every minute so as to ensure it will terminate. When the required minute is reached.


    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority". The enemy of (IT) success is complexity.
    In the absence of evidence, opinion is indistinguishable from prejudice.

      The code hits each minute by adding 60 to epoch time values. So a leap second can't cause that code to miss a particular minute. Had the code done something like sleep(60), then a negative leap second or even just a bit of the system being busy could trip it up.

      - tye        

        A negative leap second would suppress second 23:59:59 of the last day of a chosen month, so that second 23:59:58 of that date would be followed immediately by second 00:00:00 of the following date

        Therefore, there is the possibility of a 59 second minute. Ergo, the loop could step over an entire minute and, if the timing of the running of the loop was right, never terminate.

        No matter how slim the possibility, it exists.


        With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority". The enemy of (IT) success is complexity.
        In the absence of evidence, opinion is indistinguishable from prejudice.

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