Mateusz, Since the idea of voting came from you in the first place, could you please start a separate thread to DISCUSS it? :-)
BR, Alan On Thu, Nov 20, 2025 at 5:03 PM raiden00pl <[email protected]> wrote: > It's become quite a mess here, starting with the thread titled VOTE > without DISCUSSION :) The title also suggests that the lack of > POSIX compliance in NuttX is something new, which is not true. > > We've touched two separate topics here that I think deserve > their own separate discussion. The first topic: should we introduce > an option to disable signal support, similar to how we currently > disable pthreads or POSIX timers? Both options are not > POSIX-compliant, but are useful for small systems and they > have been in NuttX for a long time. > > The second topic is support for POSIX subprofiles (like PSE51), > but this is the topic for later. > > czw., 20 lis 2025 o 20:53 Tomek CEDRO <[email protected]> napisał(a): > > > Alan, Raiden, what is the exact proposition here being voted? > > One sentence that can be answered yes or no. > > > > It looks like a proposition to make NuttX "NOT POSIX Compliant". > > This violates fundamental architecutral concept and inviolables of NuttX. > > Thus my answer is NO. > > > > Implication of answering yes here is enabling mess in the long term. > > Because vote is not well defined, undocumented, with no examples or > > prototypes, anything that is on purpose not POSIX compliant could > > legally become part of NuttX making if purposefully non-posix > > compliant which violates its founding principle, and all this could be > > attributed to this vote. > > > > As a BSD Unix user on my desktop I understand that pretty well, NuttX > > has BSD Unix roots too and I love it! > > I will not tell anything about other OR/RTOS except they may not care > > about self-compatibility and standards a lot, and people have choice > > what to use or what to avoid. > > > > If anyone wants to trim down their firmware image removing all sorts > > of unused parts, that is their choice, I am fine with that, I also > > need that. > > > > But to introduce "NOT POSIX Compliant" to a project where "POSIX > > Compliance" is a design principle looks self-contradictory. > > > > Lets have a discussion first, know the details, align the solution, then > > vote. > > Lets not vote by surprise because voting is binding. > > > > Hugs :-) > > Tomek > > > > -- > > CeDeROM, SQ7MHZ, http://www.tomek.cedro.info > > > > On Thu, Nov 20, 2025 at 8:23 PM Alan C. Assis <[email protected]> wrote: > > > > > > Exactly!!! > > > > > > If we remove all non-POSIX features and remove all chips that doesn't > > have > > > MMU, NuttX will run only in 3 or 4 boards. > > > > > > Is this the direction we want to go? > > > > > > BR, > > > > > > Alan > > > > > > On Thursday, November 20, 2025, raiden00pl <[email protected]> > wrote: > > > > > > > TBH, I don't understand these -1 votes... > > > > > > > > NuttX isn't fully POSIX-compliant and never will be, unless we > > > > want to get rid of 80% of the supported targets. Full POSIX > compliance > > > > requires an MMU, for example, for proper mmap() implementation. > > > > You can't support "deeply-embedded environments" (quote from doc) and > > > > full POSIX at the same time. This is an obvious contradiction. > > > > POSIX profiles (PSE) improve this somewhat, but an MMU is still > > required > > > > for full compatibility (mmap issue). > > > > > > > > So what about the features currently present in NuttX that are > > obviously > > > > not POSIX-compliant? Like everything in `menuconfig DISABLE_OS_API`. > > > > Even the NuttX documentation indirectly states from the very > beginning > > that > > > > NuttX is NOT fully POSIX because it doesn't support fork() which is > > > > required > > > > by the POSIX base specification. > > > > > > > > czw., 20 lis 2025 o 19:41 Tomek CEDRO <[email protected]> napisał(a): > > > > > > > > > -1 from me as per this vote too sorry. > > > > > > > > > > I am sure there are other ways to accomplish that goal. > > > > > > > > > > We do not want to communicate officially in any way that we are > "NOT > > > > > POSIX Compliant" on purpose when we clearly state in many places > > > > > "strict POSIX and ANSI compliance" including the Inviolables. That > > > > > will make us incoherent and self-contradictory. > > > > > > > > > > As in my previous response, trimming down the firmware in extreme > > > > > cases can be achieved by removing unused functionalities, at the > > > > > individual responsibility of the developer. I know there may be use > > > > > cases for that, and people still want to use NuttX not the other > > RTOS, > > > > > which is important. > > > > > > > > > > My proposition is to clearly mark all POSIX functionalities, that > are > > > > > enabled and available by default, and when any of them is removed > > then > > > > > final solution is not POSIX compliant (may be not even used this is > > up > > > > > to the firmware developer) but necessary to accomplish the task. > This > > > > > provides a choice for trimming down the firmware image but sticks > to > > > > > POSIX/ANSI by default. > > > > > > > > > > This way we stick to POSIX/ANSI compliance by default. We have > clear > > > > > identification of POSIX / PE51 parts. We allow trimming down the > > final > > > > > firmware in known range of POSIX / PE51 or beyond. > > > > > > > > > > What do you think? :-) > > > > > > > > > > -- > > > > > CeDeROM, SQ7MHZ, http://www.tomek.cedro.info > > > > > > > > > > On Thu, Nov 20, 2025 at 7:16 PM Gregory Nutt <[email protected]> > > > > wrote: > > > > > > > > > > > > -1 > > > > > > > > > > > > Bad idea. Destroys the core value proposition for the OS. > > > > > > ________________________________ > > > > > > From: Alan C. Assis <[email protected]> > > > > > > Sent: Thursday, November 20, 2025 5:05 AM > > > > > > To: [email protected] <[email protected]> > > > > > > Subject: Re: [VOTE] Add support to NOT POSIX Compliant (or should > > be > > > > add > > > > > support ?) > > > > > > > > > > > > Hi Greg, > > > > > > > > > > > > Yes, I think the idea is to support POSIX subprofiles, this is > the > > case > > > > > for > > > > > > pthread, posix timers, signals, etc. > > > > > > > > > > > > I think these extreme cases are low end MCUs where we can offer > the > > > > > option > > > > > > to run a small version of NuttX, without jeopardizing the usage > for > > > > > people > > > > > > who need a compliant POSIX OS. > > > > > > > > > > > > BR, > > > > > > > > > > > > Alan > > > > > > > > > > > > On Thu, Nov 20, 2025 at 9:50 AM Gregory Nutt < > [email protected]> > > > > > wrote: > > > > > > > > > > > > > There should only be extreme conditions where any POSIX API is > > > > > > > non-compliant. POSIX complience is a core value of the OS and > > should > > > > > not > > > > > > > be violated. If we lose POSIX compliance then we have > > destroyed the > > > > > > > meaning for the existence of the operating system. I hopr that > > no > > > > one > > > > > will > > > > > > > ever tolerate that to happen. > > > > > > > > > > > > > > The only legitimate cases I can think of are due to hardware > > > > > limitations. > > > > > > > For example, certain features of mmap() and fork() cannot be > > support > > > > if > > > > > > > there is no MMU. uCLinux had the same limitations. > > > > > > > ________________________________ > > > > > > > From: Alan C. Assis <[email protected]> > > > > > > > Sent: Thursday, November 20, 2025 4:39 AM > > > > > > > To: dev <[email protected]> > > > > > > > Subject: [VOTE] Add support to NOT POSIX Compliant (or should > be > > add > > > > > > > support ?) > > > > > > > > > > > > > > Hi Everyone, > > > > > > > > > > > > > > Some years ago NuttX was able to fit in really small MCUs (in > > fact I > > > > > got it > > > > > > > running on a chip using less than 2KB RAM). > > > > > > > > > > > > > > But a few years ago those options to disable SIGNALS, VFS, etc > > were > > > > > > > disabled to create a system that was fully POSIX compliant. > > > > > > > > > > > > > > Unfortunately we missed the details: POSIX also aims at systems > > > > without > > > > > > > resources, as is the case of POSIX PE51 (POSIX PSE51 is a > > specific, > > > > > minimal > > > > > > > profile or subset of the full POSIX - Portable Operating System > > > > > Interface > > > > > > > standard, formally defined in IEEE 1003.13-2003). > > > > > > > > > > > > > > Almost two years ago I opened an issue about it: > > > > > > > https://github.com/apache/nuttx/issues/11390 > > > > > > > > > > > > > > Today Mr Chengdong opened a PR to bring back the possibility to > > > > disable > > > > > > > signals: > > > > > > > https://github.com/apache/nuttx/pull/17352 > > > > > > > > > > > > > > But as Mateusz (raiden00pl) pointed we need to be careful about > > it to > > > > > avoid > > > > > > > breaking the Inviolables: > > > > > > > > > > > > > > ## Strict POSIX compliance > > > > > > > > > > > > > > - Strict conformance to the portable standard OS interface as > > > > > defined at > > > > > > > OpenGroup.org. > > > > > > > > > > > > > > > > > > > > > * - A deeply embedded system requires some special support. > > Special > > > > > > > support must be minimized.* - The portable interface must > never > > be > > > > > > > compromised only for the sake of > > > > > > > expediency. > > > > > > > - Expediency or even improved performance are not > > justifications > > > > for > > > > > > > violation of the strict POSIX interface. > > > > > > > > > > > > > > Fortunately Greg chose well his words: "Special support must be > > > > > minimized". > > > > > > > It doesn't mean it could exist, we just need to take care to > not > > > > become > > > > > > > normal or goal and jeopardize the system. > > > > > > > > > > > > > > So in this sense I propose to vote a suggestion: > > > > > > > > > > > > > > In the configuration where we already add an option to disable > > posix > > > > > timer, > > > > > > > pthreads, etc we add an option to "Enable POSIX PE51 subset". > > > > > > > > > > > > > > This way someone willing to disable signals will be aware > he/she > > is > > > > > > > creating a system that is not POSIX fully compliant or it is > > just a > > > > > subset > > > > > > > of a POSIX OS. > > > > > > > > > > > > > > BR, > > > > > > > > > > > > > > Alan > > > > > > > > > > > > > > > > > > >
