Re: [Bug 221186] New: clock_gettime CLOCK_TAI is incorrectly specified

[Alejandro Colomar <alx@kernel.org>]

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Hi,

On 2026-03-07T14:21:17+0000, bugzilla-daemon@kernel.org wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=221186
> 
>             Bug ID: 221186
>            Summary: clock_gettime CLOCK_TAI is incorrectly specified
>            Product: Documentation
>            Version: unspecified
>           Hardware: All
>                 OS: Linux
>             Status: NEW
>           Severity: normal
>           Priority: P3
>          Component: man-pages
>           Assignee: documentation_man-pages@kernel-bugs.osdl.org
>           Reporter: mpatocka@redhat.com
>         Regression: No
> 
> The man page for clock_gettime says "CLOCK_TAI (since Linux 3.10;
> Linux-specific)
> A nonsettable system-wide clock derived from wall-clock time but ignoring leap
> seconds."
> 
> When UTC was announced, it was already 10 seconds behind TAI. Since that, 27
> leap seconds have been added. According to the man page, the difference between
> wall clock an CLOCK_TAI should be 27 seconds, but in it is 37 seconds in fact.
> The kernel is correct (it returns 37 as the difference between TAI and UTC),
> but the man page should be fixed to reflect that.
> 
> I suggest to change the man page to:
> 
> CLOCK_TAI (since Linux 3.10; Linux-specific)
> A nonsettable system-wide clock showing physical time elapsed since Jan 1 1970
> 0:00:00.00 TAI (Dec 31 1969 23:59:50.00 UTC). This clock does not experience
> discontinuities and backwards jumps caused by NTP inserting leap seconds as
> CLOCK_REALTIME does. This clock changes when system time is adjusted by the
> user or NTP for the purpose of correcting wrong time setting. TAI means temps
> atomique international (International Atomic Time).

Would you mind sending a patch?

BTW, Paul, would you mind reviewing this bug report and suggestion?


Have a lovely day!
Alex

-- 
<https://www.alejandro-colomar.es>

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