[weblacky]

I can only add to this indirectly, when I was in college we had fairly free access to the ANSI gateway online and some large businesses like Microsoft do/did as well for full time employees. Most UNIX stuff I know about when down between between 1996-1998. Around 2004, I took the opportunity grab every single standards document related to Ada and POSIX I could find with a little POSIX C cross-over. I still have those PDF now 20+ years later...ughh...it's been that long.

While I could be very wrong (and am happy to be proven so, on this topic)...I was lead to believe that the last and greatest UNIX updates occured before the year 2000 and not much or anything has happened since then due to the death or mergers of so many MAJOR players in the old UNIX world. Compared to what we used to have we have like 1/2 or less.

In terms of "finding" whether a UNIX variant has a feature...you are suppose to use feature test macros. Some C macros are literally feature names and some are ANSI POSIX standards number and date (it's not standardize, convention I guess)?

here: https://www.gnu.org/software/libc/manual...acros.html

So if you're hard-core UNIX, you're supposed to have all these preprocessor macros add features (should they be supported) but somehow have as much support as possible without them (AIO is good example of this).

In terms of the "history" of a feature (it's origins and iterations through time) I'd assume it's a secret due to the intellectual property laws? Anecdotally I'm sure some pieces here or there were said by the creators in various books or memoirs. Other than getting headers or source and reading them from various OSes yourself, I'm unsure how this info could be assembled.