From owner-cvs-src@FreeBSD.ORG  Tue Apr 10 15:03:45 2007
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From: "M. Warner Losh" <imp@bsdimp.com>
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Cc: grog@freebsd.org, cvs-src@freebsd.org, src-committers@freebsd.org,
	brian@freebsd.org, cvs-all@freebsd.org
Subject: Re: cvs commit: src/usr.bin/touch touch.1 touch.c
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In message: <Pine.LNX.4.64.0704101101450.24971@hermes-1.csi.cam.ac.uk>
            Tony Finch <dot@dotat.at> writes:
: On Tue, 10 Apr 2007, Greg 'groggy' Lehey wrote:
: >
: > The definition of time_t is simply a number of seconds since a
: > specified event.
: 
: ... modulo leap second adjustments.
: 
: time_t cannot encode UTC correctly since you need more than a simple
: scalar to do so (e.g. you need a TAI offset or a leap second flag).

Yes.  POSIX defined time_t to be UTC, and then forgot that there's
leap seconds in UTC.  UTC uses a variable radix notation for just such
events, which translates poorly to a single number.  Or at least
translates poorly to time_t which is defined such that one cannot take
them into account.

Warner