Strange output from zdump for 2038
autarch at urth.org
Mon Jul 21 15:40:51 UTC 2003
On Mon, 21 Jul 2003, Olson, Arthur David (NIH/NCI) wrote:
> The zdump manual page notes the output to be expected when using the -v
> -v For each zonename on the command line, print the time
> at the lowest possible time value, the time one day
> after the lowest possible time value, the times both
> one second before and exactly at each detected time
> discontinuity, the time at one day less than the
> highest possible time value, and the time at the
> highest possible time value, Each line ends with
> isdst=1 if the given time is Daylight Saving Time or
> isdst=0 otherwise.
> So the two 1901 lines and the two 2038 lines are to be expected.
An explicit mention of the 32-bit int overflow problem might be in order,
I think. Something along the lines of:
Because most systems represent seconds since the epoch as a 32-bit int,
discontinuities may be incorrectly detected when this int overflows. For
a signed 32-bit int, this will occur in the years 1901 and 2038. The
discontinuities reported because of this overflow do not represent
actual changes in that time zone.
House Absolute Consulting
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