Re: unix epoch data wrapping

[Ethan M. <merritt@u.washington.edu>]

On Saturday 27 March 2010, Jonathan Thornburg wrote:
> If I write the 2-digit year "50", does it mean 1950 or 2050?
>         [Let's leave aside the possibility of other centuries.]
> In the original poster's case, I gather that 1950 would have been the
> correct interpretation.  But if I were plotting future values of a
> retirement portfolio, 2050 would probably be the better choice.
> Fundamentally, there is no way for gnuplot to know the "correct"
> choice, so it has to make an arbitrary choice (which will be wrong
> a fair number of times).

Indeed. 
And if you are plotting a timeline of Roman emperors, "68" really
does mean 68, the year of Nero's death. 

There is no end to this quagmire.  The behaviour of a program may even
depend on which library version it is linked against. Consider this
lovely bit from the man page for strptime: 
   The  'y' (year in century) specification is taken to specify a year in
   the 20th century by libc4 and libc5. It is taken to be a year  in  the
   range  1950-2049  by  glibc 2.0. It is taken to be a year in 1969-2068
   since glibc 2.1.

So yes, I'll add a note in the documentation.  But better by far not to
use two-digit dates.

	Ethan