If you disable signal, and call some of the signal functions, the compiler
and linker will report the error directly.
but 32/64bit time_t/clock_t report the error only after your devices run
more than several days/weeks/months.
so, I prefer to remove Kconfig to avoid the runtime error and more
compatible with POSIX.
here is the size change before and after
https://github.com/apache/nuttx/pull/18840 on stm32f4discovery:nsh:
| Section | master | PR | Δ bytes | Δ % |
| ------------------ | -----: | ----: | -----: | ----: |
| `.text`            | 84 376 | 85 056 | **+680** | +0.81 % |
| `.ARM.exidx`       |      8 |      8 |       0  |  0.00 % |
| `.data`            |    884 |    888 |    +4    | +0.45 % |
| `.bss`             |  4 504 |  4 600 |   +96    | +2.13 % |
| `.comment`         |     68 |     68 |     0    |  0.00 % |
| `.ARM.attributes`  |     44 |     44 |     0    |  0.00 % |
| `.debug_frame`     |    428 |    496 |   +68    | +15.9 % |
| `.debug_line_str`  |    216 |    216 |     0    |  0.00 % |
| **Total (sum)**    | 90 528 | 91 376 | **+848** | +0.94 % |



On Sun, May 3, 2026 at 10:13 PM Alan C. Assis <[email protected]> wrote:

> Exactly, but the point is: if we can fix it now, why to merge a PR and
> later spend time adding it back to Kconfig ?
>
> See the "signal" history as an example, it was removed some years ago, and
> then we spent a lot of time and energy discussing how to return with it (at
> least partial signal disable).
>
> I think just changing the Kconfig to CONFIG_SYSTEM_TIME64 default Y will
> fix the issue since all boards will have it be default and only someone
> willing to run NuttX on some small MCU or retro hardware can disable it.
>
> This way is better than removing the support to TIME 32-bit all together.
>
> BR,
>
> Alan
>
> On Sun, May 3, 2026 at 10:47 AM Matteo Golin <[email protected]>
> wrote:
>
> > Size could be a valid concern. We can always add the ability to go back
> to
> > 32 bit time in Kconfig. Does this have any concerns with violating POSIX?
> > I'd imagine not, given that it used to be 32 bit.
> >
> > On Sun, May 3, 2026, 9:33 AM Alan C. Assis <[email protected]> wrote:
> >
> > > Hi Matheusz,
> > >
> > > Thank you , so probably I forgot about this discussion. Sorry Xiang for
> > > raising this Discussion, but I thought it wasn't discussed before.
> > >
> > > Anyway I think we need to see how much it will increase in Flash/RAM.
> > >
> > > If it increases "a lot" (more than 700 bytes), maybe we should keep
> this
> > > config and just make it default Y, because people could use NuttX on
> > small
> > > microcontrollers that could be left behind with this change.
> > >
> > > This is part of the "The Inviolable Principles of NuttX: All Users
> > Matter",
> > > especially that part:
> > > -
> > >
> > > *Hobbyists are valued users of the OS including retro computing
> hobbyists
> > > and DIY “Maker” hobbyists.*
> > > In the past we already did drastic modifications that increased NuttX
> > size
> > > and now we are trying to figure out how to fix what we did.
> > >
> > > BR,
> > >
> > > Alan
> > >
> > > On Sun, May 3, 2026 at 9:17 AM raiden00pl <[email protected]>
> wrote:
> > >
> > > > 32 bit time is not compatible with the latest POSIX and it was
> already
> > > > agreed that this change would be included in release 13 in one of
> > > > the previous discussions on this topic. We were just waiting for
> > release
> > > > 13.
> > > >
> > > > niedz., 3 maj 2026 o 13:52 Alan C. Assis <[email protected]>
> > napisał(a):
> > > >
> > > > > Hi Everyone,
> > > > > I want to bring this PR to your attention:
> > > > > https://github.com/apache/nuttx/pull/18840
> > > > >
> > > > > I have some concerns like those added to my Change Request there.
> > > > >
> > > > > I think broad modifications like this need to be discussed with our
> > > > > community.
> > > > >
> > > > > I'm not against this PR, it will avoid the 2038 Unix Epoch BUG, but
> > it
> > > is
> > > > > important to know first the impact of this commit to small
> > > > > microcontrollers.
> > > > >
> > > > > Unfortunately we don't have how many bytes this PR will add/remove
> > > > to/from
> > > > > Flash and RAM.
> > > > >
> > > > > Also we discussed many times that all PRs need to include valid
> > > testing,
> > > > > just "checkpatch.sh -f" is not a real test, it doesn't guarantee
> that
> > > the
> > > > > PR will pass in the CI.
> > > > >
> > > > > In cases like this where a PR modifies many boards and MCUs, a good
> > > idea
> > > > it
> > > > > to test it on your own github account first, before submitting the
> > PR,
> > > as
> > > > > explained here: https://github.com/apache/nuttx/issues/18568
> > > > >
> > > > > This is not a criticism of the author, that is my friend, but it is
> > > > > important that we improve our process. Seems like we are still
> > messing
> > > > with
> > > > > basic things.
> > > > >
> > > > > BR,
> > > > >
> > > > > Alan
> > > > >
> > > >
> > >
> >
>

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