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From: gordon@sneaky.lonestar.org (Gordon Burditt)
Newsgroups: comp.unix.xenix.misc
Subject: Re: The switch to daylight savings time
Keywords: CMOS, date, DST, setclock, time, TZ, Xenix 3.0
Message-ID: <53746@sneaky.lonestar.org>
Date: 13 Apr 91 21:35:58 GMT
References: <PINKAS.91Apr9141415@st860.intel.com> <1991Apr10.114836.10816@convex.com> <8050@eos.arc.nasa.gov>
Distribution: usa
Organization: Gordon Burditt
Lines: 28

>I'd like to jump into this discussion because we're having trouble with our
>4.3 BSD systems (which are running the ntp daemon also!).  I noticed that in
>/usr/src/lib/libc/gen/ctime.c the rules for DST are defined.  Ours was the

Notice also that ctime.c is not linked into the kernel.  It is linked into
lots of application and utility programs.  If your ctime.c does not use an 
external file to determine the rules for DST, you need to modify ctime.c
for the new rules.  (Better to bite the bullet NOW and convert to using
a file).  Then you ***RELINK ALMOST EVERY EXECUTABLE IN THE SYSTEM***
(except the kernel) that uses ctime.c (really localtime()), including, 
of course, applications for which you don't have linkable object.  

comp.sources.unix had a very nice localtime package posted a few years
back.  

It is possible to have a hodge-podge of programs, some that recognize the
new rules (they were linked with the comp.sources.unix localtime package),
and some that didn't (all the system-supplied programs in Tandy 6000
Xenix before Xenix 3.2.0 and the 3.2 development system upgrade, which
didn't come out at the same time).  

The kernel in some systems contains defaults for the number of hours west
of GMT, and whether or not the system EVER has daylight savings time.
(Some areas in the United States don't, last time I checked).  It does
not contain the switchover rules.

						Gordon L. Burditt
						sneaky.lonestar.org!gordon