(tz_compute): If time to switch to DST is later in the year switch back in the next year.

1 files changed, 13 insertions, 2 deletions

diff --git a/time/tzset.c b/time/tzset.c
index c35017c960..0621cd9af7 100644
--- a/time/tzset.c
+++ b/time/tzset.c
@@ -517,9 +517,20 @@ tz_compute (timer, tm)
      time_t timer;
      const struct tm *tm;
 {
-  if (! compute_change (&tz_rules[0], 1900 + tm->tm_year) ||
-      ! compute_change (&tz_rules[1], 1900 + tm->tm_year))
+  if (! compute_change (&tz_rules[0], 1900 + tm->tm_year))
     return 0;
+  /* We have to distinguish between northern and southern hemisphere.
+     For the later the daylight saving time ends in the next year.  */
+  if (tz_rules[0].change < tz_rules[1].change)
+    {
+      if (! compute_change (&tz_rules[1], 1900 + tm->tm_year))
+	return 0;
+    }
+  else
+    {
+      if (! compute_change (&tz_rules[1], 1900 + tm->tm_year + 1))
+	return 0;
+    }
 
   __daylight = tz_rules[0].offset != tz_rules[1].offset;
   __timezone = -tz_rules[0].offset;