#4328: New APIs added to POSIX Standard (2021)

Sun Mar 21 07:28:40 UTC 2021

Gentlemen,

Awesome, thanks!  I see how that works now...I'll give it a thorough
look tomorrow and will update the spreadsheet accordingly. I'll pipe
back up when I have a more accurate look of what's currently there.
Thanks again and have a great Sunday!

Matt

On Fri, Mar 19, 2021 at 8:27 PM Joel Sherrill <joel at rtems.org> wrote:
>
>
>
> On Fri, Mar 19, 2021 at 1:08 PM Gedare Bloom <gedare at rtems.org> wrote:
>>
>> On Fri, Mar 19, 2021 at 11:16 AM Matthew Joyce <mfjoyce2004 at gmail.com> wrote:
>> >
>> > Dr. Joel,
>> >
>> > Thanks very much...I'll keep working to get a sense of what goes
>> > where! In the meantime, where can I look to get the ground truth of
>> > which methods are "in RTEMS" as opposed to those in newlib?
>> >
>> There is only one ground truth:
>> git://git.rtems.org/rtems.git
>>
>> And for newlib
>>
>> git://sourceware.org/git/newlib-cygwin.git
>>
>> That said, searching for the function name symbols in compiled
>> libraries is a good first step to rule out newlib. Then, you can
>> 'grep' the RTEMS source code for the function names to see if they
>> exist there.
>
>
> rtems/cpukit to be specitic. It won't be implemented anywhere else.
>
> And clearly we both have forgotten that networking APIs are in the
> rtems-libbsd repository.
>
> https://git.rtems.org/rtems-libbsd/
>
> I suspect ppoll() might already be in there. Or at least supported by
> FreeBSD.
>
> You should clone everything and grep the sources. newlib already has
> qsort_r. This is the nm I used:
>
> $ ~/rtems-work/tools/6/bin/sparc-rtems6-nm ~/rtems-work/tools/6/sparc-rtems6/lib/libc.a | grep qsort_r
> lib_a-bsd_qsort_r.o:
> 00000000 T __bsd_qsort_r
> lib_a-qsort_r.o:
> 00000000 T qsort_r
>
> Notice the last line has "T qsort_r" which says it is defined.
>
> grep -r in the newlib source shows it is in ./libc/search/qsort_r.c
>
> dladdr() looks to be prototyped in RTEMS but hidden behind an ifdef like it
> wasn't ported from NetBSD so that looks possible. It is in rtems.
>
> Those two examples should help you figure out why you missed
> finding some things that were implemented.
>
> I need to figure out what this next POSIX version is to be called
> so I can update the tracking spreadsheet that generates the RTEMS
> POSIX Compliance Guide, :)
>
> --joel
>>
>>
>> > Thanks again!
>> >
>> > Matt
>> >
>> > On Fri, Mar 19, 2021 at 1:58 PM Joel Sherrill <joel at rtems.org> wrote:
>> > >
>> > > Keep devel@ on the list. :)
>> > >
>> > > On Fri, Mar 19, 2021 at 7:51 AM Matthew Joyce <mfjoyce2004 at gmail.com> wrote:
>> > >>
>> > >> Sir,
>> > >>
>> > >> Thank you for the link! I see that you're right, those last four are
>> > >> in newlib, plus memmem(). I updated those in the Google Sheet.
>> > >>
>> > >> Now I see the newlib part, but where are you referring to specifically
>> > >> when you say RTEMS, as in "POSIX support comes from a mix of RTEMS and
>> > >> newlib"?
>> > >
>> > >
>> > > POSIX is a HUGE HUGE standard and references other standards. One
>> > > it references and pulls in is the C99 Standard C Library which is libc and
>> > > libm. RTEMS mostly does not implement this functionality and relies on
>> > > another open source project for those APIs. Newlib is an open source
>> > > C Library used by RTEMS, Cygwin, and most embedded systems GNU tools
>> > > chains.
>> > >
>> > > Most of the POSIX header files with RTEMS are actually in Newlib even
>> > > if they originated with RTEMS. Many are shared with Cygwin.
>> > >
>> > > So methods like the string, memory, and *printf come from Newlib since they
>> > > are in C99. We provide POSIX like threading, signals, core file access, and
>> > > much more.
>> > >
>> > > It's a complementary relationship but it takes a bit to figure out when
>> > > something should be in one or the other. The line gets blurred at times.
>> > >
>> > > Say you added a new CPU architecture implementation of a math
>> > > method (like Eshan did last year), then it goes in newlib. But he also
>> > > added some POSIX methods which go in RTEMS. In either case,
>> > > we like tests for them in RTEMS to show they work in our environment.
>> > >
>> > > --joel
>> > >
>> > >
>> > >
>> > >>
>> > >> Thanks again!
>> > >>
>> > >> Matt
>> > >>
>> > >> On Fri, Mar 19, 2021 at 1:13 PM Joel Sherrill <joel at rtems.org> wrote:
>> > >> >
>> > >> >
>> > >> >
>> > >> > On Fri, Mar 19, 2021, 6:40 AM Joel Sherrill <joel at rtems.org> wrote:
>> > >> >>
>> > >> >>
>> > >> >>
>> > >> >> On Fri, Mar 19, 2021, 5:48 AM Matthew Joyce <mfjoyce2004 at gmail.com> wrote:
>> > >> >>>
>> > >> >>> https://docs.google.com/spreadsheets/d/1reCNOIZC5JTwQENgl-hvG8THfQqNtlUDVy_07PYodic/edit?usp=sharing
>> > >> >>>
>> > >> >>> Hello,
>> > >> >>>
>> > >> >>> As suggested by Dr. Sherril, I've taken an initial look through this
>> > >> >>> document https://www.opengroup.org/austin/docs/austin_1110.pdf and
>> > >> >>> added the new methods  to a Googe Sheet, linked above.
>> > >> >>>
>> > >> >>> None of them appear to be in the RTEMS POSIX API Users Guide, but
>> > >> >>> maybe that's not the right place to look. I'll stand by for your
>> > >> >>> feedback regarding what's possible / desirable to add to RTEMS.
>> > >> >>
>> > >> >>
>> > >> >> It is possible they are in our C Library or Math Library.  Or just not in the manual. The POSIX manual tends to be sparse since you can always use man pages or the POSIX standard.
>> > >> >>
>> > >> >> Since you have RTEMS and tools built. Find one of the libc.a and libm.a files in the tools install and librtemscpu.a in the RTEMS build or install. Then try a command something like this:
>> > >> >>
>> > >> >> CPU-rtems6-nm LIBRARY | grep SYMBOL
>> > >> >>
>> > >> >> If you see it list with T then it is in the text section and there.
>> > >> >
>> > >> >
>> > >> > Following up, I initially answered from my phone and didn't look at source.  I am still on my phone but looked through the list and think the last four methods are probably the only ones currently supported.
>> > >> >
>> > >> > https://sourceware.org/git/?p=newlib-cygwin.git;a=tree;f=newlib/libc/string;h=ceeec602cdd0e6b5c6b002b741bda9b41da4e441;hb=HEAD
>> > >> >
>> > >> > POSIX support comes from a mix of RTEMS and newlib. That's key to this type of project.
>> > >> >
>> > >> > --joel
>> > >> >>
>> > >> >>
>> > >> >>
>> > >> >>>
>> > >> >>> Thanks very much for your time!
>> > >> >>>
>> > >> >>> Sincerely,
>> > >> >>>
>> > >> >>> Matt
>> > _______________________________________________
>> > devel mailing list
>> > devel at rtems.org
>> > http://lists.rtems.org/mailman/listinfo/devel