Re: [musl] C23 implications for C libraries

[enh <enh@google.com>]

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On Wed, May 3, 2023 at 11:19 PM Jₑₙₛ Gustedt <jens.gustedt@inria.fr> wrote:

> Hi,
>
> on Wed, 3 May 2023 15:58:26 -0700 you (enh <enh@google.com>) wrote:
>
> > (i share others' skepticism that timespec_get() is very useful,
>
> I don't think that these interfaces by themselves are the most
> interesting. The original motivation to create these interfaces stem
> from the creation the integration of threads in to the C standard. And
> there the monotonic and thread-specific clocks make all their sense.
>
> But also having process cpu usage in a well-defined interface (`clock`
> usage is not portable for that) is a win.
>

sure, but the more esoteric the clocks, the less likely _that_ part is to
be portable anyway.


> > and especially that non-ISO bases will ever be useful to anyway, but
> > i like the idea of allowing future additions to "just work" with an
> > old libc enough that i've implemented bionic's
> > timespec_get()/timespec_getres() in this style.)
>
> Great!
>
> Do you have a link to that?


https://android-review.googlesource.com/c/platform/bionic/+/2576754


> The particular choices of values become
> part of the ABI, sort-of. So it would be better to be consistent
> between implementations.
>

are there any two linux libcs that are abi compatible? i didn't think so.


> Would this motivate musl to accept patches for the optional bases that
> come with C23? Or maybe the whole set?
>

i think bionic and musl are philosophically quite different there --- musl
seems to try to stick to the exact letter of ISO/POSIX, whereas with bionic
i accept that for everything you can possibly imagine, _someone_ will be
trying to do it, and -- unless you're actually going to prohibit it via
selinux/seccomp for security or privacy reasons -- i may as well make it as
minimally painful as possible.


> Thanks
> Jₑₙₛ
>
> --
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