ctime problem (PR 939)

[Andreas Jaeger <aj@arthur.rhein-neckar.de>]

Hi,

Mike send us a bug report where he reported what looks like a strange
bug.  For full details of the discussion so far, please read PR
libc/939.

Calling the appended program with TZ set for Great Britain, ctime(0)
report 1 o'clock - but strftime report the right time:

$ TZ=Europe/London ./ctimetry 
time_t 0 converts to Thu Jan  1 01:00:00 1970
Time zones are GMT and  BST
00:00:00 1970/01/01
Daylight saving is off
strftime reports: Thu, 01 Jan 1970 00:00:00 +0000 GMT

Mike reported this for 2.0.7 but I can reproduce this with 2.0.112.

If using localtime instead of gmtime the output is:
$ TZ=Europe/London ./ctimetry 
time_t 0 converts to Thu Jan  1 01:00:00 1970
Time zones are GMT and  BST
01:00:00 1970/01/01
Daylight saving is off
strftime reports: Thu, 01 Jan 1970 01:00:00 +0100 BST

Note especially the BST.

I'm puzzled at the moment.  Could anybody please look into this and
tell me what's wrong?

Thanks,
Andreas

#include <stdio.h>
#include <sys/types.h>
#include <time.h>
main (int argc, char **argv)
{
        time_t x;
        struct tm *t;
	char s[1000];
	
        x = 0l;
        printf ("time_t %ld converts to %s", x, ctime (&x));
        printf ("Time zones are %s and  %s\n", tzname[0], tzname[1]);
#if 1
        t = gmtime (&x);
#else
	t = localtime (&x);
#endif
        printf ("%02d:%02d:%02d ", t->tm_hour, t->tm_min, t->tm_sec);
        printf ("%04d/%02d/%02d\n",
                (t->tm_year + 1900), (t->tm_mon + 1), t->tm_mday);
        printf ("Daylight saving is %s\n", t->tm_isdst ? "on" : "off");
	strftime (s, sizeof(s),  "%a, %d %b %Y %T %z %Z", t);
	printf ("strftime reports: %s\n", s);
}

-- 
 Andreas Jaeger   aj@arthur.rhein-neckar.de    jaeger@informatik.uni-kl.de
  for pgp-key finger ajaeger@aixd1.rhrk.uni-kl.de