?
H. Peter Anvin wrote:
> Followup to:? <[email protected]>
> By author:??? "Brandon S. Allbery KF8NH" <[email protected]>
> In newsgroup: linux.dev.kernel
> >
> > In message <[email protected]>, 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
>
> --
> ??? PGP: 2047/2A960705 BA 03 D3 2C 14 A8 A8 BD? 1E DF FE 69 EE 35 BD 74
> ??? See http://www.zytor.com/~hpa/ for web page and full PGP public key
> ??????? I am Bah?'? -- ask me about it or see http://www.bahai.org/
> ?? "To love another person is to see the face of God." -- Les Mis?rables
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> Please read the FAQ at http://www.tux.org/lkml/faq.html