Re: [LEAPSECS] building consensus

From: John Cowan <>
Date: Mon, 5 Jun 2006 02:08:27 -0400

M. Warner Losh scripsit:

> : The designers of Posix time thought it was more important to preserve
> : the property that dividing the difference between two time_t values
> : by 60, 3600, 86400 would give minutes, hours, days.
> That's the one property that Posix time_t does not have. The
> difference between time_t's that cross a leap second are off by one
> second, and therefore do not start with the right answer to do the
> division...

I expressed myself badly. My point is that if you have a Posix time_t
representing 11:22:33 UTC on a certain day, and you add 86400 to that
time_t, you will get the Posix representation of 11:22:33 UTC on the
following day, whether a leap second intervenes or not. This is a valuable
property, many existing programs depended on it, and the authors of the
Posix spec preserved it at the expense of having a distinct representation
for each UTC second.

You may call this position wrong (and I have done so), but it is
unquestionably defensible.

> It would be better to say the number of SI seconds since 1972 rather
> than UTC seconds, I think.


They do not preach                              John Cowan
  that their God will rouse them      
    A little before the nuts work loose.
They do not teach
  that His Pity allows them                         --Rudyard Kipling,
    to drop their job when they damn-well choose.   "The Sons of Martha"
Received on Sun Jun 04 2006 - 23:14:30 PDT

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