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

[Gedare Bloom]

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.

> 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
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