BTW, I'm saying that the idea of creating the VOTE image was yours, just saying you commented we need to have a vote for that PR that disables signals. ;-)
BR, Alan On Thu, Nov 20, 2025 at 5:13 PM Alan C. Assis <[email protected]> wrote: > 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 >> > > > > > > >> > > > > >> > > > >> > >> >
