2019-01-15 17:19:24 +0100, Joerg Schilling: [...] > > I don't think GNU/Debian systems care about XSI, or the UNIX > > trademark either. AFAICT, they concern themselves with the POSIX > > base, and pick XSI extensions when they are useful (and don't > > break their own backward compatibility). > > But this is not how standards are helpful and this may be the underlying > reason, why Linux finally decided not to follow POSIX even though they got the > offer to be validated for free. [...]
(note that since we're talking of the shell and utilities, Linux (the kernel) has little relevance). As a script writer, the XSI option is (was) useful to people who want(ed) to write scripts portable to SysV like systems, or systems that have obtained UNIX certification, and don't care about non-UNIX/SysV systems. When you read the standard and notice one part is flagged "XSI", that's an indication that while it should work on SysV systems (the last time I used one of those systems for real was over 15 years ago), it probably doesn't on BSDs and may work on GNU/Linux. Given that most of the current software development is done for GNU/Linux, that XSI option that comes from a time when it was about SysV vs BSD is not that useful. That offer of free validation was more about giving credibility/visibility to the OpenGroup than to GNU/Linux if you ask me. It would be a wasted effort to implement the less useful XSI features (that nobody missed in the 30 years GNU/Linux have been around), just to get access to that "UNIX" brand (which I suppose would go to one version of one of the GNU/Linux distributions, I can't see how all the hundreds of GNU/Linux based systems could become certified at once). -- Stephane
