[tz] zic changes (2/2)

Aurelien Jarno aurelien at aurel32.net
Wed Mar 9 22:35:21 UTC 2016

On 2016-03-08 01:54, Paul Eggert wrote:
> Aurelien Jarno wrote:
> >Are you sure you have the posixrules file installed in
> >/tmp/prefix/zoneinfo/posixrules?
> No, I didn't have those installed, because glibc 'make install' doesn't
> install them. Your hint let me figure out what I needed to do to reproduce
> the problem.
> I eventually tracked this down to a bug in glibc, which Sébastien Brissaud
> reported on February 27. See:
> https://sourceware.org/bugzilla/show_bug.cgi?id=19738
> The bug is that glibc adds the posixrules file's first transition time (the
> minimum time_t value -2147483648) to the UTC offset -28800, and this
> addition overflows and wraps around to a large positive number.

Thanks a lot for finding that.

> I proposed a glibc patch here:
> https://sourceware.org/bugzilla/attachment.cgi?id=9074
> I don't see a good zic workaround for this glibc bug.  zic could emit a
> slightly later transition time (a day later, say), but this would cause
> programs to mishandle time stamps near the origin at 1901-12-13.

And thanks for the patch. I have subscribed to the bug, so I can track
the review progress.


Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien at aurel32.net                 http://www.aurel32.net

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