POSIX Compilance- #2966, GSoC Project 2019

[Gedare Bloom]

Hi Vaibhav,

Please try to use plain text mode in your post, the font sizes are
hard to read. More below.

On Sat, Mar 16, 2019 at 3:50 PM Vaibhav Gupta <vaibhavgupta40 at gmail.com> wrote:
>
> Hello,
> As mentioned by Dr Joel that high priority is to be given to implementations missing in FACE GPP 3.0.
> So, I have got FACE Technical Standard 3.0 pdf downloaded. And its pretty easy to compare tickets now.
> .
> And while exploring big picture I got many questions:
>
> 1 - It is mentioned in the ticket #2966, "RTEMS POSIX Compliance is achieved via a combination of methods and .h files in RTEMS and the newlib C Library." .
> So, if a method or a header is present in Newlib C, it is not required to be present in RTEMS library? But that would mean Newlib is directly ported to RTEMS.
> .
> > I had an off-list talk with Vijay, he proved to be very helpful. I asked him same question (question 1), I would like to conclude what we discussed.
>
> > He told that "RTEMS uses its own version of Newlib C as it cannot directly mirror original Newlib as, if methods change the way it works, they can break RTEMS".
>
> > But then my doubt was, if that's the case, why keep modified headers of original Newlib under separate Newlib C folder in RTEMS? Why not directly include them in RTEMS library? (As I found newlib-1d35a003f.tar.gz in {RTEMS-ROOT}/rsb/rtems/sources/    )
> .
> > To which he replied,  "RTEMS version of newlib is being used as a libraby of RTEMS only and the posix functions are being linked to this newlib"
> .
> 2- So, My second doubt is that our target is to contribute to Newlib C or RTEMS Library? Or we will add methods to Newlib C and link them to RTEMS?
>

The goal is to add whatever can be added to the Newlib C, it will
eventually make its way into RTEMS (when we bump to a snapshot/release
of newlib that includes the addition). We prefer to try to get this
POSIX stuff implemented in Newlib.  For this, you might want to see if
you can get some advice from Aditya who went through this process 2
years ago or so.

Gedare

> Thanks
> Vaibhav Gupta
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