From: Paul Eggert <eggert@cs.ucla.edu> Date: Fri, 26 Jan 2018 07:39:30 -0800 Subject: Re: [tz] OpenJDK/CLDR/ICU/Joda issues with Ireland change | Unfortunately tm_gmtoff is not standardized by C or POSIX, perhaps | because standardizers mistakenly thought that strftime %z was enough. No, it would have been because tm_gmtoff isn't available everywhere (and most particularly, wasn't available on the main reference system from which most of POSIX was copied.) Standards groups should (and the posix people mostly do) specify what users can expect to have work, and how to make that happen. When things only work, or can only be used, sometimes, that's not suitable to be standardised. It is possible that after all of this time, enough of the world that matters has tm_gmtoff (and tm_zone) that POSIX may be persuaded to add them - but at best that could not happen until the next major revision, which is years away if I read the signs correctly. They could indicate that it will happen though (which also would give those implementations which still don't support those fields time to catch up.) I paricipate (a bit - mostly wrt the shell definition) in the group that does the work, I will (in a week or two, when I have systems back working that allow me to do it rationally) file a bug report with them, and see what happens (it is likely to garner some immediate reaction, but will take more than a year to reach the head of the queue and actually get some possible action, one way or the other). kre ps: I know that posix has not been immune from the need to invent, but they are better than many others in that regard. It is also possible that this may be regarded as more a C issue, and best deferred to them, in which case someone else would need to learn how to see if any action can be started there.