Update POSIX compliance guide

[Eshan Dhawan]

On Thu, Mar 26, 2020 at 1:49 AM Gedare Bloom <gedare at rtems.org> wrote:

> On Wed, Mar 25, 2020 at 1:21 PM Joel Sherrill <joel at rtems.org> wrote:
> >
> >
> >
> > On Wed, Mar 25, 2020 at 12:59 PM Eshan Dhawan <eshandhawan51 at gmail.com>
> wrote:
> >>
> >> I went through the implementations in FreeBSD, NetBSD and musl
> >> they all require fork().
> >> So they can't be used by RTEMS.
> >
> >
> > Read
> https://pubs.opengroup.org/onlinepubs/9699919799/functions/wordexp.html
> and see
> > that it even includes an example of how you could implement this using
> forking
> > echo and using pipes to capture the output.
> >
> It's not required though. We can do a clean implementation of it
> without fork, and provide some use case with RTEMS shell. This would
> be a nice bit of coding work for GSoC beyond porting/fixup. I'd
> strongly encourage it.
>
I have added it to the list and starting to study more about it.

>
> > I'm open to ideas on a small string to put in the Compliance spreadsheet
> to mark
> > methods that we will never support. All of the posix_spawn() and this
> fall into that
> > category. This would help avoid this analysis happening again.
> >
> > And once we figure that out, I hope I can figure out the magic in the
> Python script
> > that generates the document from the spreadsheet. :)
> >
> > Gedare.. do you think we should add a section to the POSIX Users Guide on
> > Unsupportable Methods? Not full man pages but maybe a subsection per
> header
> > file with unsupportable methods, the list of methods and some rationale?
> >
> Wouldn't hurt. It'll take some doing though, and isn't appropriate as
> a GSoC milestone but could be a side-contribution.
>
> >>
> >>
> >> On Wed, Mar 25, 2020 at 11:17 PM Gedare Bloom <gedare at rtems.org> wrote:
> >>>
> >>> Hi Eshan,
> >>>
> >>> We can work with the newlib community. Some things can be done in
> >>> newlib that are only for RTEMS, while some things we should share with
> >>> others, and still more code may be not useable by RTEMS (e.g., what is
> >>> in sys/linux). It is best to try to make common code available, but if
> >>> some code has to be specialized for RTEMS differently than how it
> >>> works in other systems then we can do that.
> >>>
> >>> Gedare
> >>>
> >>> On Wed, Mar 25, 2020 at 11:06 AM Eshan Dhawan <eshandhawan51 at gmail.com>
> wrote:
> >>> >
> >>> > I will check the musl for a more RTEMS  supported implementation.
> >>> > but will newlib change the implementation??
> >>> >
> >>> > On Wed, Mar 25, 2020 at 8:26 PM Joel Sherrill <joel at rtems.org>
> wrote:
> >>> >>
> >>> >>
> >>> >>
> >>> >> On Sun, Mar 22, 2020 at 2:00 PM Eshan Dhawan <
> eshandhawan51 at gmail.com> wrote:
> >>> >>>
> >>> >>> I have also checked wordexp.h is completely present in newlib
> (libc/include)
> >>> >>> the implementation of the functions wordexp.c and wordfree.c  is
> in (libc/posix)
> >>> >>> But the compliance status shows not supported.
> >>> >>
> >>> >>
> >>> >> I don't see them in libc.a for the sparc:
> >>> >>
> >>> >> lib_a-wordexp.o:
> >>> >>
> >>> >> lib_a-wordfree.o:
> >>> >>
> >>> >>
> >>> >> It is not included in RTEMS because the newlib implementation
> requires multiple
> >>> >> processes. It uses fork() and pipes.
> >>> >>
> >>> >> Maybe MUSCL has an implementation that is embedded friendly but the
> compliance
> >>> >> guide is correct.
> >>> >>
> >>> >> --joel
> >>> >>
> >>> >>>
> >>> >>>
> >>> >>>
> >>> >>> On Sat, Mar 21, 2020 at 11:31 PM Joel Sherrill <joel at rtems.org>
> wrote:
> >>> >>>>
> >>> >>>>
> >>> >>>>
> >>> >>>>
> >>> >>>> On Sat, Mar 21, 2020, 8:47 AM Eshan Dhawan <
> eshandhawan51 at gmail.com> wrote:
> >>> >>>>>
> >>> >>>>> Hello everyone
> >>> >>>>>
> >>> >>>>> I went through the POSIX Compliance guide and it showed that
> wcsncasecmp_l () was not supported in wchar.h
> >>> >>>>> But when I checked newlib it had been implemented in libc/string
> >>> >>>>> so I think it needs to be updated in the docs.
> >>> >>>>
> >>> >>>>
> >>> >>>> Thanks for spotting this. I did a spot check and think there were
> a few more wc* methods that were not in the spreadsheet. I am going to post
> a patch in a bit.  Please check it.
> >>> >>>>
> >>> >>>> Obviously, this is a csv file maintained externally in a
> spreadsheet. If you put it in a spreadsheet, you can turn on data filtering
> based on the top row. Then you can do "queries" to do things like filter
> down to what's in a single header file. Or what's required in one standard
> but not in another.
> >>> >>>>
> >>> >>>> FWIW this turned into a bit of a rat hole. I tried to double
> check the newlib git repo and the link on their website is wrong after the
> upgrade of sourceware.org. Then checked gdb and it had the same issue.
> This resulted in also reporting some leftover cleanup from the recent
> upgrade of sourceware.org.
> >>> >>>>>
> >>> >>>>>
> >>> >>>>> Thanks
> >>> >>>>> Eshan
> >>> >
> >>> > _______________________________________________
> >>> > devel mailing list
> >>> > devel at rtems.org
> >>> > http://lists.rtems.org/mailman/listinfo/devel
>
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