Should we document a time zone for the RTEMS epoch?

[Joel Sherrill]

On Wed, Feb 10, 2021, 10:53 AM Sebastian Huber <
sebastian.huber at embedded-brains.de> wrote:

> On 10/02/2021 17:47, Joel Sherrill wrote:
>
> >
> >
> > On Wed, Feb 10, 2021, 10:30 AM Sebastian Huber
> > <sebastian.huber at embedded-brains.de
> > <mailto:sebastian.huber at embedded-brains.de>> wrote:
> >
> >     On 10/02/2021 07:53, Sebastian Huber wrote:
> >
> >     > Hello,
> >     >
> >     > I try to update the clock manager documentation and noticed that
> >     there
> >     > is no time zone specified for the RTEMS epoch. In the timecounter
> >     > initialization we use:
> >     >
> >     > static struct timehands th0 = {
> >     > [...]
> >     > #ifdef __rtems__
> >     >     .th_bintime = { .sec = TOD_SECONDS_1970_THROUGH_1988 },
> >     >     .th_microtime = { TOD_SECONDS_1970_THROUGH_1988, 0 },
> >     >     .th_nanotime = { TOD_SECONDS_1970_THROUGH_1988, 0 },
> >     >     .th_boottime = { .sec = TOD_SECONDS_1970_THROUGH_1988 - 1 },
> >     > #endif /* __rtems__ */
> >     >
> >     > [...]
> >     >
> >     > };
> >     >
> >     > Since Unix epoch is 1970-01-01T00:00:00Z, this basically defines
> >     that
> >     > the RTEMS epoch is 1988-01-01T00:00:00Z. Should this be documented?
> >     > The current implementation also implies that the time reported by
> >     > RTEMS is in UTC (modulo leap seconds).
> >
> >     I tried to document the clocks provided by RTEMS, see tail of
> >     (glossary.rst):
> >
> >     https://lists.rtems.org/pipermail/devel/2021-February/064451.html
> >     <https://lists.rtems.org/pipermail/devel/2021-February/064451.html>
> >
> >
> > Is it sufficient to reference the epoch entry in various clock get
> > time method pages?
> The relevant epoch and clock is now referenced in the directives.
> >
> > And should there be discussion somewhere about TZ environment variable
> > and the methods in newlib which account for that.
> I think a time zone is simply not accounted for in the RTEMS Classic
> API. With the setting above I guess the time zone is fixed to UTC.
>

By default clock_gettime is also UTC. You have to go through the C Library
time methods to get timezones

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