[Bug libc/14606] New: lost 1h in gmtime, ctime extracted date

[Bug libc/14606] New: lost 1h in gmtime, ctime extracted date

[eugene.kopyshev at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14606

             Bug #: 14606
           Summary: lost 1h in gmtime, ctime extracted date
           Product: glibc
           Version: 2.11
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: unassigned@sourceware.org
        ReportedBy: eugene.kopyshev@gmail.com
                CC: drepper.fsp@gmail.com
    Classification: Unclassified


Every year, random day in Oct, ctime resolves two different epoch times into
the same string date. tz not set, not affected, not makes an influence. For
example:

1351385541 2012-10-28 1:52:21 Sun Oct 28 01:52:21 2012
1351389141 2012-10-28 1:52:21 Sun Oct 28 01:52:21 2012

A code to get output as above:

#include<time.h>
#include<stdio.h>

int main()
{
time_t t;
struct tm *tm;

    t=1351385541;
    tm=gmtime(&t);
    printf( "%lu %d-%d-%d %d:%d:%d %s", t, tm->tm_year+1900, tm->tm_mon+1,
tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec, ctime(&t) );
    t=1351389141;
    tm=gmtime(&t);
    printf( "%lu %d-%d-%d %d:%d:%d %s", t, tm->tm_year+1900, tm->tm_mon+1,
tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec, ctime(&t) );
}

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[Bug libc/14606] lost 1h in gmtime, ctime extracted date

[schwab@linux-m68k.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=14606

Andreas Schwab <schwab@linux-m68k.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |INVALID

--- Comment #1 from Andreas Schwab <schwab@linux-m68k.org> 2012-09-22 09:26:58 UTC ---
The dates are in different time zones, crossing a DST changeover.  See
tm_isdst.

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[Bug libc/14606] lost 1h in gmtime, ctime extracted date

[eugene.kopyshev at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14606

--- Comment #2 from Eugene Kopyshev <eugene.kopyshev at gmail dot com> 2012-09-22 10:09:10 UTC ---
Hi Andreas,

Right, but with tm.tm_isdst=0 it works for all "modern" dates and fails
somewhen before the 19xx. Changeover did not exist then?

57718800 Sun Oct 31 02:00:00 1971
57722400 Sun Oct 31 02:00:00 1971

With tm_isdst=-1 it does not work for any year. In case with http server
application is makes tricky to cover past dates... ok, nobody needs it,
hopefully.

Thanka s lot!

2012/9/22 schwab@linux-m68k.org <sourceware-bugzilla@sourceware.org>

>
> http://sourceware.org/bugzilla/show_bug.cgi?id=14606
>
> Andreas Schwab <schwab@linux-m68k.org> changed:
>
>            What    |Removed                     |Added
>
> ----------------------------------------------------------------------------
>              Status|NEW                         |RESOLVED
>          Resolution|                            |INVALID
>
> --- Comment #1 from Andreas Schwab <schwab@linux-m68k.org> 2012-09-22
> 09:26:58 UTC ---
> The dates are in different time zones, crossing a DST changeover.  See
> tm_isdst.
>
> --
> Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email
> ------- You are receiving this mail because: -------
> You reported the bug.
>

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[Bug libc/14606] lost 1h in gmtime, ctime extracted date

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=14606

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|                            |security-

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