Re: Different unixtimes, same localtime

[Florian Weimer <fw at deneb dot enyo dot de>]

* Dario Teixeira:

> Either I've found a bug in localtime_r or I'm missing
> something about its usage (probably the latter).
> The problem is that I'm getting the exact same tm structure
> for invocations of localtime_r with different Unix times.
> Now, the times I'm using are special in that they represent
> the same localtime in the provided locale.  Nevertheless,
> the smaller one (212541000L) happened when DST was in effect,
> whereas the second one (212544600L) happened one hour later
> was DST was no longer in effect.  Shouldn't this difference
> be signaled in the tm_isdst field?

I think the changing offset to UTC is not due to a DST change, but a
time zone change for Europe/Lisbon:

fw@deneb:~$ zdump -v Europe/Lisbon | grep 1976
Europe/Lisbon  Sat Sep 25 23:59:59 1976 UT = Sun Sep 26 00:59:59 1976 CET isdst=0 gmtoff=3600
Europe/Lisbon  Sun Sep 26 00:00:00 1976 UT = Sun Sep 26 00:00:00 1976 WET isdst=0 gmtoff=0

>From the tzdata/europe source file:

# Zone  NAME            GMTOFF  RULES   FORMAT  [UNTIL]
Zone    Europe/Lisbon   -0:36:45 -      LMT     1884
                        -0:36:45 -      LMT     1912 Jan  1 # Lisbon Mean Time
                         0:00   Port    WE%sT   1966 Apr  3  2:00
                         1:00   -       CET     1976 Sep 26  1:00
                         0:00   Port    WE%sT   1983 Sep 25  1:00s
                         0:00   W-Eur   WE%sT   1992 Sep 27  1:00s
                         1:00   EU      CE%sT   1996 Mar 31  1:00u
                         0:00   EU      WE%sT

So I would say that localtime_r gives the right result.