Re: [PATCH] t4212: handle systems with post-apocalyptic gmtime

From: Jeff King <peff@peff.net>
Date: Mar 26, 2014, 21:57 UTC
Message-ID: <20140326215741.GA17716@sigill.intra.peff.net>
In-Reply-To: <20140326212227.GC6991@hashpling.org>

On Wed, Mar 26, 2014 at 09:22:27PM +0000, Charles Bailey wrote:

Show 15 quoted lines

> On Wed, Mar 26, 2014 at 03:33:59PM -0400, Jeff King wrote:
> > 
> > That being said, is the AIX value actually right? I did not look closely
> > at first, but just assumed that it was vaguely right. But:
> > 
> >   999999999999999999 / (86400 * 365)
> > 
> > is something like 31 billion years in the future, not 160 million.
> > A real date calculation will have a few tweaks (leap years, etc), but
> > that is orders of magnitude off.
> 
> Well, this is embarrassing, while moving this through the corporate
> firewall (aka typing on one machine while looking at another), I
> munged the date. It still doesn't seem right but at least you can now
> see the actual data.

Hmm, so the year you got is actually: 1623969404. That still seems off to me by a factor 20. I don't know if this is really worth digging into that much further, but I wonder what you would get for timestamps of:

  99999999999999999
  9999999999999999
  999999999999999
  etc.

Do we start generating weird values at some particular size? Or is AIX gmtime really more clever than I am, and is accounting for wobble of the Earth or something over the next billion years?

-Peff