[Ntp] CLOCK_TAI (was NTPv5: big picture)

[Hal Murray <[e-mail]>]

>> My (Linux) man page has various options for clock_gettime(), but
>> it doesn't say anything about leap seconds or TAI.  Yes, it should be
>> reasonable to add, but it's not there yet.

> Which only says that you should not trust your decision-making on what the
> man-page for a single command, it's not telling you the full story.

> So, there is CLOCK_TAI for starters. Then you also need to look at the
> nanokernel support, which is there, and the leap-second handling, leap-second
> information it does keep in the kernel. It's been there for fairly long now,
> that we can consider the Linux kernel to support it for all the versions we
> consider. All we need to do is keep supplying it with correct time and
> correct leap-second information.

Thanks for the heads up.

It's been in the Linux kernel for years.
       CLOCK_TAI (since Linux 3.10; Linux-specific)
              A nonsettable system-wide clock derived from wall-clock
              time but ignoring leap seconds.  This clock does not
              experience discontinuities and backwards jumps caused by
              NTP inserting leap seconds as CLOCK_REALTIME does.

It was recently added to the Linux Man Pages.  The new text is in Fedora 34, 
not in Fedora 33, not in Debian 10/buster.

It's not in NetBSD or FreeBSD.

A quick search for >CLOCK_TAI Windows< didn't find anything indicating it was 
implemented.



-- 
These are my opinions.  I hate spam.