Re: What TZ do you use to get right time w/ clockspeed?

On thursday, nov 14, 2002, at 22:43 Europe/Stockholm, Paul Jarc wrote:
> I've found that some packages' compile-time tests assume a POSIX
> clock, so the tests break if they run in a right/ zone.

There's definately a lot of software out there that doesn't think
a bit about leapseconds. One example is the Apple's Foundation
framework (Objective-C class library) that assumes there are 978307200
seconds between 1970-01-01 00:00:00 and 2001-01-01 00:00:00.

That value is hardcoded so there's no way you can get the right
behaviour even if you change to the  right/ zone files. I've sent
Apple a bug report of course. :-)

   http://tancred.com/malte/blog/2002/05/17.html#taiutccocoa

> Maybe I was wrong about leapsecs.dat not being a DJB invention.  The
> data comes from elsie, I think, but I can't find any non-libtai
> software that uses that particular file.  The glibc sources don't
> mention it, AFAICT.

The leapsecs.dat is definately a libtai feature:

   malte% cd libtai-0.60
   malte% cat leapsecs.txt
   # http://pobox.com/~djb/libtai/leapsecs.txt, version 1998-10-13
   #
   # Official sources:
   # http://maia.usno.navy.mil/leapsec.html
   # http://hpiers.obspm.fr/webiers/general/earthor/utc/UTC.html
   #
   # Dates must be listed in sorted order.
   # + means a positive leap second, inserting 23:59:60 UTC.
   # - means a negative leap second, skipping 23:59:59 UTC.
   #
   # Note for parsers: Negative leap seconds will probably never happen, 
but
   # the year 10000 will happen. Please don't contribute to the Y10K 
problem.
   #
   # 1972-01-01 00:00:00 UTC was 1972-01-01 00:00:10 TAI.
   #
   +1972-06-30
   +1972-12-31
   +1973-12-31
   +1974-12-31
   +1975-12-31
   +1976-12-31
   +1977-12-31
   +1978-12-31
   +1979-12-31
   +1981-06-30
   +1982-06-30
   +1983-06-30
   +1985-06-30
   +1987-12-31
   +1989-12-31
   +1990-12-31
   +1992-06-30
   +1993-06-30
   +1994-06-30
   +1995-12-31
   +1997-06-30
   +1998-12-31

The program leapsecs generates a leapsecs.dat from the text file.

Cheerio,
Malte