On Sat, Jun 03, 2017 at 12:04:32AM +0200, Ulrich Mueller wrote: > Actually, the POSIX definition for %Z continues: "or by no bytes if no > timezone information exists." So also returning an empty string would > be compliant (but maybe not very helpful). > [...] > I agree that GMT+0200 could be misleading. But what about resolving %Z > the same as %z in the case of the author's time zone, as was suggested > earlier? It is supposed to be human-readable output, or do we expect > that someone would use the %Z output and e.g. plug it back into their > TZ? Yeah, I think these are the only real contenders: an empty string, or "+0200" (which _isn't_ confusing, because it doesn't have the abbreviation in front of it, so it pretty clearly is an offset from GMT). I don't have a preference between the other two. The remaining question is whether we want to care about preserving the system %Z for the local-timezone case. -Peff