[ntp:questions] Leap second to be introduced in June

David Woolley david at ex.djwhome.demon.invalid
Wed Jan 14 22:43:04 UTC 2015


On 14/01/15 16:37, Terje Mathisen wrote:
> The calls I'm thinking of are those you make to convert an OS-supplied
> time_t (file) system timestamp to YMDHMS etc.

Those calls have no need to be in the kernel, and they are not in 
Unix/Linux systems.
>
> I.e. even Windows (which uses a seconds-based timestamp with 100 ns
> resolution) has calls exactly like that. Those are the calls that would
> need to be updated in order to work in (TAI * 1e7).

There is no need to update them on Debian Wheezy, and probably most 
Linux and modern Unix systems.


david at dhcppc4:~$ TZ=/usr/share/zoneinfo/right/UTC date -d '30 June 2012 
86399 seconds'
Sat Jun 30 23:59:59 UTC 2012
david at dhcppc4:~$ TZ=/usr/share/zoneinfo/right/UTC date -d '30 June 2012 
86400 seconds'
Sat Jun 30 23:59:60 UTC 2012
david at dhcppc4:~$ TZ=/usr/share/zoneinfo/right/UTC date -d '30 June 2012 
86401 seconds'
Sun Jul  1 00:00:00 UTC 2012

I haven't double checked that this is not a trick in the user interface 
code, and they don't work for future time, until the leap second has 
been declared and distributed (in the tzdata files):

david at dhcppc4:~$ TZ=/usr/share/zoneinfo/right/UTC date -d '30 June 2014 
86400 seconds'
Tue Jul  1 00:00:00 UTC 2014

The inability to record future civil times in an efficient format is one 
of the disadvantages of TAI.





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