> Followup to: <199809092149.RAA06993@hilfy.ece.cmu.edu>
> By author: "Brandon S. Allbery KF8NH" <allbery@kf8nh.apk.net>
> In newsgroup: linux.dev.kernel
> >
> > In message <19980909200032.B13292@caffeine.ix.net.nz>, Chris Wedgwood writes:
> > +-----
> > | On Wed, Sep 09, 1998 at 12:59:47AM +0000, H. Peter Anvin wrote:
> > | > The way xntp deals with leap seconds is it lets the epoch float...
> > | > i.e. it holds time_t to the same value for two seconds.
> > | Cool... so 1970 becomes even longer ago that I would have assumed
> > | then?
> > +--->8
> >
> > That's the only semi-reasonable (I stress *semi-*) interpretation one can
> > give to the current standard. The other possibilities are worse.
> >
>
> Right. I think the right solution is one I suggested on c.o.l.d.s
> recently:
>
> - time_t being a 64-bit signed integer linked to UTC
> - struct timespec (and struct timeval, presumably) having an extra
> field added:
>
> 64-bit seconds field (same as time_t) linked to UTC
> 32-bit nanosecond field (microsecond for timeval) linked to TAI
> 32-bit integral TAI-UTC difference
>
> That way any moment in time will be uniquely derivable at least, at a
> positive leap second, you will see the progression (where T means a
> time_t value divisible by 86400):
>
Why would you have the TAI-UTC difference instead of just TAI?
The part of your message below was very confusing to me.
>
> tv_sec tv_delta UTC
>
> T-3 N 23:59:57
> T-2 N 23:59:58
> T-1 N 23:59:59
> T-1 N+1 23:59:60
> T N+1 00:00:00
> T+1 N+1 00:00:01
> T+2 N+1 00:00:02
>
> ... and for a negative leap second ...
>
> tv_sec tv_delta
>
> T-3 N 23:59:57
> T-2 N 23:59:58
> T N-1 00:00:00
> T+1 N-1 00:00:01
> T+2 N-1 00:00:02
>
> We may want to have a testable bit that we're "in" a leap second for
> the 23:59:60 case...
>
> -hpa
>
> --
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>
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