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-rw-r--r--ChangeLog7
-rw-r--r--time/mktime.c20
2 files changed, 21 insertions, 6 deletions
diff --git a/ChangeLog b/ChangeLog
index c140a1d873..b8f57104cd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2002-02-02 Paul Eggert <eggert@twinsun.com>
+
+ * src/mktime.c [defined DEBUG && STDC_HEADERS]: Include <string.h>.
+ (__mktime_internal): If no tm_isdst is requested, prefer solutions
+ with tm_isdst > 0 when the requested time falls within a
+ spring-forward gap [PR libc/2894].
+
2002-02-03 Andreas Schwab <schwab@suse.de>
* stdio-common/tst-rndseek.c: Increase timeout.
diff --git a/time/mktime.c b/time/mktime.c
index 7cfd297037..5f3f3f23f8 100644
--- a/time/mktime.c
+++ b/time/mktime.c
@@ -49,6 +49,7 @@
# include <stdio.h>
# if STDC_HEADERS
# include <stdlib.h>
+# include <string.h>
# endif
/* Make it work even if the system's libc has its own mktime routine. */
# define mktime my_mktime
@@ -236,6 +237,9 @@ __mktime_internal (struct tm *tp,
int year_requested = tp->tm_year;
int isdst = tp->tm_isdst;
+ /* 1 if the previous probe was DST. */
+ int dst2;
+
/* Ensure that mon is in range, and set year accordingly. */
int mon_remainder = mon % 12;
int negative_mon_remainder = mon_remainder < 0;
@@ -270,20 +274,24 @@ __mktime_internal (struct tm *tp,
tm.tm_yday = tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
t0 = ydhms_tm_diff (year, yday, hour, min, sec, &tm);
- for (t = t1 = t2 = t0 + *offset;
+ for (t = t1 = t2 = t0 + *offset, dst2 = 0;
(dt = ydhms_tm_diff (year, yday, hour, min, sec,
ranged_convert (convert, &t, &tm)));
- t1 = t2, t2 = t, t += dt)
+ t1 = t2, t2 = t, t += dt, dst2 = tm.tm_isdst != 0)
if (t == t1 && t != t2
- && (isdst < 0 || tm.tm_isdst < 0
- || (isdst != 0) != (tm.tm_isdst != 0)))
+ && (tm.tm_isdst < 0
+ || (isdst < 0
+ ? dst2 <= (tm.tm_isdst != 0)
+ : (isdst != 0) != (tm.tm_isdst != 0))))
/* We can't possibly find a match, as we are oscillating
between two values. The requested time probably falls
within a spring-forward gap of size DT. Follow the common
practice in this case, which is to return a time that is DT
away from the requested time, preferring a time whose
- tm_isdst differs from the requested value. In practice,
- this is more useful than returning -1. */
+ tm_isdst differs from the requested value. (If no tm_isdst
+ was requested and only one of the two values has a nonzero
+ tm_isdst, prefer that value.) In practice, this is more
+ useful than returning -1. */
break;
else if (--remaining_probes == 0)
return -1;