Update tzcode to 2025b

MFC after:	3 weeks

Differential Revision:	https://reviews.freebsd.org/D52103

contrib/tzcode/Makefile

@@ -137,7 +137,7 @@ TIME_T_ALTERNATIVES_TAIL = int_least32_t.ck uint_least32_t.ck \
   uint_least64_t.ck
 
 # What kind of TZif data files to generate.  (TZif is the binary time
-# zone data format that zic generates; see Internet RFC 8536.)
+# zone data format that zic generates; see Internet RFC 9636.)
 # If you want only POSIX time, with time values interpreted as
 # seconds since the epoch (not counting leap seconds), use
 #	REDO=		posix_only
@@ -255,6 +255,7 @@ LDLIBS=
 #  -DHAVE_UNISTD_H=0 if <unistd.h> does not work*
 #  -DHAVE_UTMPX_H=0 if <utmpx.h> does not work*
 #  -Dlocale_t=XXX if your system uses XXX instead of locale_t
+#  -DMKTIME_MIGHT_OVERFLOW if mktime might fail due to time_t overflow
 #  -DPORT_TO_C89 if tzcode should also run on mostly-C89 platforms+
 #	Typically it is better to use a later standard.  For example,
 #	with GCC 4.9.4 (2016), prefer '-std=gnu11' to '-DPORT_TO_C89'.
@@ -262,7 +263,7 @@ LDLIBS=
 #	feature (integers at least 64 bits wide) and maybe more.
 #  -DRESERVE_STD_EXT_IDS if your platform reserves standard identifiers
 #	with external linkage, e.g., applications cannot define 'localtime'.
-#  -Dssize_t=long on hosts like MS-Windows that lack ssize_t
+#  -Dssize_t=int on hosts like MS-Windows that lack ssize_t
 #  -DSUPPORT_C89=0 if the tzcode library should not support C89 callers
 #	Although -DSUPPORT_C89=0 might work around latent bugs in callers,
 #	it does not conform to POSIX.
@@ -285,7 +286,7 @@ LDLIBS=
 #	This mishandles some past timestamps, as US DST rules have changed.
 #	It also mishandles settings like TZ='EET-2EEST' for eastern Europe,
 #	as Europe and US DST rules differ.
-#  -DTZNAME_MAXIMUM=N to limit time zone abbreviations to N bytes (default 255)
+#  -DTZNAME_MAXIMUM=N to limit time zone abbreviations to N bytes (default 254)
 #  -DUNINIT_TRAP if reading uninitialized storage can cause problems
 #	other than simply getting garbage data
 #  -DUSE_LTZ=0 to build zdump with the system time zone library
@@ -319,7 +320,8 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 \
   $(GCC_INSTRUMENT) \
   -Wall -Wextra \
   -Walloc-size-larger-than=100000 -Warray-bounds=2 \
-  -Wbad-function-cast -Wbidi-chars=any,ucn -Wcast-align=strict -Wdate-time \
+  -Wbad-function-cast -Wbidi-chars=any,ucn -Wcast-align=strict -Wcast-qual \
+  -Wdate-time \
   -Wdeclaration-after-statement -Wdouble-promotion \
   -Wduplicated-branches -Wduplicated-cond -Wflex-array-member-not-at-end \
   -Wformat=2 -Wformat-overflow=2 -Wformat-signedness -Wformat-truncation \
@@ -336,7 +338,7 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 \
   -Wsuggest-attribute=noreturn -Wsuggest-attribute=pure \
   -Wtrampolines -Wundef -Wunused-macros -Wuse-after-free=3 \
   -Wvariadic-macros -Wvla -Wwrite-strings \
-  -Wno-format-nonliteral -Wno-sign-compare
+  -Wno-format-nonliteral -Wno-sign-compare -Wno-type-limits
 #
 # If your system has a "GMT offset" field in its "struct tm"s
 # (or if you decide to add such a field in your system's "time.h" file),
@@ -614,8 +616,8 @@ TZS_YEAR=	2050
 TZS_CUTOFF_FLAG=	-c $(TZS_YEAR)
 TZS=		to$(TZS_YEAR).tzs
 TZS_NEW=	to$(TZS_YEAR)new.tzs
-TZS_DEPS=	$(YDATA) asctime.c localtime.c \
+TZS_DEPS=	$(YDATA) localtime.c private.h \
-			private.h tzfile.h zdump.c zic.c
+			strftime.c tzfile.h zdump.c zic.c
 TZDATA_DIST = $(COMMON) $(DATA) $(MISC)
 # EIGHT_YARDS is just a yard short of the whole ENCHILADA.
 EIGHT_YARDS = $(TZDATA_DIST) $(DOCS) $(SOURCES) tzdata.zi
@@ -855,10 +857,10 @@ tzselect:	tzselect.ksh version
 		chmod +x $@.out
 		mv $@.out $@
 
-check: check_mild back.ck
+check: check_mild back.ck now.ck
 check_mild: check_web check_zishrink \
   character-set.ck white-space.ck links.ck mainguard.ck \
-  name-lengths.ck now.ck slashed-abbrs.ck sorted.ck \
+  name-lengths.ck slashed-abbrs.ck sorted.ck \
   tables.ck ziguard.ck tzs.ck
 
 # True if UTF8_LOCALE does not work;
@@ -1103,7 +1105,7 @@ set-timestamps.out: $(EIGHT_YARDS)
 		   touch -md @1 test.out; then \
 		  rm -f test.out && \
 		  for file in $$files; do \
-		    if git diff --quiet $$file; then \
+		    if git diff --quiet HEAD $$file; then \
 		      time=$$(TZ=UTC0 git log -1 \
 			--format='tformat:%cd' \
 			--date='format:%Y-%m-%dT%H:%M:%SZ' \
@@ -1354,13 +1356,13 @@ long-long.ck unsigned.ck: $(VERSION_DEPS)
 zonenames:	tzdata.zi
 		@$(AWK) '/^Z/ { print $$2 } /^L/ { print $$3 }' tzdata.zi
 
-asctime.o:	private.h tzfile.h
+asctime.o:	private.h
 date.o:		private.h
 difftime.o:	private.h
-localtime.o:	private.h tzfile.h tzdir.h
+localtime.o:	private.h tzdir.h tzfile.h
-strftime.o:	private.h tzfile.h
+strftime.o:	localtime.c private.h tzdir.h tzfile.h
-zdump.o:	version.h
+zdump.o:	private.h version.h
-zic.o:		private.h tzfile.h tzdir.h version.h
+zic.o:		private.h tzdir.h tzfile.h version.h
 
 .PHONY: ALL INSTALL all
 .PHONY: check check_mild check_time_t_alternatives

contrib/tzcode/NEWS

@@ -1,5 +1,108 @@
 News for the tz database
 
+Release 2025b - 2025-03-22 13:40:46 -0700
+
+  Briefly:
+    New zone for Aysén Region in Chile which moves from -04/-03 to -03.
+
+  Changes to future timestamps
+
+    Chile's Aysén Region moves from -04/-03 to -03 year-round, joining
+    Magallanes Region.  The region will not change its clocks on
+    2025-04-05 at 24:00, diverging from America/Santiago and creating a
+    new zone America/Coyhaique.  (Thanks to Yonathan Dossow.)  Model
+    this as a change to standard offset effective 2025-03-20.
+
+  Changes to past timestamps
+
+    Iran switched from +04 to +0330 on 1978-11-10 at 24:00, not at
+    year end.  (Thanks to Roozbeh Pournader.)
+
+  Changes to code
+
+    'zic -l TIMEZONE -d . -l /some/other/file/system' no longer
+    attempts to create an incorrect symlink, and no longer has a
+    read buffer underflow.  (Problem reported by Evgeniy Gorbanev.)
+
+
+Release 2025a - 2025-01-15 10:47:24 -0800
+
+  Briefly:
+    Paraguay adopted permanent -03 starting spring 2024.
+    Improve pre-1991 data for the Philippines.
+    Etc/Unknown is now reserved.
+
+  Changes to future timestamps
+
+    Paraguay stopped changing its clocks after the spring-forward
+    transition on 2024-10-06, so it is now permanently at -03.
+    (Thanks to Heitor David Pinto and Even Scharning.)
+    This affects timestamps starting 2025-03-22, as well as the
+    obsolescent tm_isdst flags starting 2024-10-15.
+
+  Changes to past timestamps
+
+    Correct timestamps for the Philippines before 1900, and from 1937
+    through 1990.  (Thanks to P Chan for the heads-up and citations.)
+    This includes adjusting local mean time before 1899; fixing
+    transitions in September 1899, January 1937, and June 1954; adding
+    transitions in December 1941, November 1945, March and September
+    1977, and May and July 1990; and removing incorrect transitions in
+    March and September 1978.
+
+  Changes to data
+
+    Add zone1970.tab lines for the Concordia and Eyre Bird Observatory
+    research stations.  (Thanks to Derick Rethans and Jule Dabars.)
+
+  Changes to code
+
+    strftime %s now generates the correct numeric string even when the
+    represented number does not fit into time_t.  This is better than
+    generating the numeric equivalent of (time_t) -1, as strftime did
+    in TZDB releases 96a (when %s was introduced) through 2020a and in
+    releases 2022b through 2024b.  It is also better than failing and
+    returning 0, as strftime did in releases 2020b through 2022a.
+
+    strftime now outputs an invalid conversion specifier as-is,
+    instead of eliding the leading '%', which confused debugging.
+
+    An invalid TZ now generates the time zone abbreviation "-00", not
+    "UTC", to help the user see that an error has occurred.  (Thanks
+    to Arthur David Olson for suggesting a "wrong result".)
+
+    mktime and timeoff no longer incorrectly fail merely because a
+    struct tm component near INT_MIN or INT_MAX overflows when a
+    lower-order component carries into it.
+
+    TZNAME_MAXIMUM, the maximum number of bytes in a proleptic TZ
+    string's time zone abbreviation, now defaults to 254 not 255.
+    This helps reduce the size of internal state from 25480 to 21384
+    on common platforms.  This change should not be a problem, as
+    nobody uses such long "abbreviations" and the longstanding tzcode
+    maximum was 16 until release 2023a.  For those who prefer no
+    arbitrary limits, you can now specify TZNAME_MAXIMUM values up to
+    PTRDIFF_MAX, a limit forced by C anyway; formerly tzcode silently
+    misbehaved unless TZNAME_MAXIMUM was less than INT_MAX.
+
+    tzset and related functions no longer leak a file descriptor if
+    another thread forks or execs at about the same time and if the
+    platform has O_CLOFORK and O_CLOEXEC respectively.  Also, the
+    functions no longer let a TZif file become a controlling terminal.
+
+    'zdump -' now reads TZif data from /dev/stdin.
+    (From a question by Arthur David Olson.)
+
+  Changes to documentation
+
+    The name Etc/Unknown is now reserved: it will not be used by TZDB.
+    This is for compatibility with CLDR, which uses the string
+    "Etc/Unknown" for an unknown or invalid timezone.  (Thanks to
+    Justin Grant, Mark Davis, and Guy Harris.)
+
+    Cite Internet RFC 9636, which obsoletes RFC 8536 for TZif format.
+
+
 Release 2024b - 2024-09-04 12:27:47 -0700
 
   Briefly:
@@ -116,7 +219,7 @@ Release 2024b - 2024-09-04 12:27:47 -0700
   Changes to commentary
 
     Commentary about historical transitions in Portugal and her former
-    colonies has been expanded with links to many relevant legislation.
+    colonies has been expanded with links to relevant legislation.
     (Thanks to Tim Parenti.)
 
 
@@ -204,10 +307,10 @@ Release 2023d - 2023-12-21 20:02:24 -0800
     changing its time zone from -01/+00 to -02/-01 at the same moment
     as the spring-forward transition.  Its clocks will therefore not
     spring forward as previously scheduled.  The time zone change
-    reverts to its common practice before 1981.
+    reverts to its common practice before 1981.  (Thanks to Jule Dabars.)
 
     Fix predictions for DST transitions in Palestine in 2072-2075,
-    correcting a typo introduced in 2023a.
+    correcting a typo introduced in 2023a.  (Thanks to Jule Dabars.)
 
   Changes to past and future timestamps
 

contrib/tzcode/asctime.c

@@ -7,6 +7,7 @@
 
 /*
 ** Avoid the temptation to punt entirely to strftime;
+** strftime can behave badly when tm components are out of range, and
 ** the output of strftime is supposed to be locale specific
 ** whereas the output of asctime is supposed to be constant.
 */
@@ -18,27 +19,6 @@
 #include "un-namespace.h"
 #include <stdio.h>
 
-/*
-** All years associated with 32-bit time_t values are exactly four digits long;
-** some years associated with 64-bit time_t values are not.
-** Vintage programs are coded for years that are always four digits long
-** and may assume that the newline always lands in the same place.
-** For years that are less than four digits, we pad the output with
-** leading zeroes to get the newline in the traditional place.
-** The -4 ensures that we get four characters of output even if
-** we call a strftime variant that produces fewer characters for some years.
-** This conforms to recent ISO C and POSIX standards, which say behavior
-** is undefined when the year is less than 1000 or greater than 9999.
-*/
-static char const ASCTIME_FMT[] = "%s %s%3d %.2d:%.2d:%.2d %-4s\n";
-/*
-** For years that are more than four digits we put extra spaces before the year
-** so that code trying to overwrite the newline won't end up overwriting
-** a digit within a year and truncating the year (operating on the assumption
-** that no output is better than wrong output).
-*/
-static char const ASCTIME_FMT_B[] = "%s %s%3d %.2d:%.2d:%.2d     %s\n";
-
 enum { STD_ASCTIME_BUF_SIZE = 26 };
 /*
 ** Big enough for something such as
@@ -52,14 +32,24 @@ enum { STD_ASCTIME_BUF_SIZE = 26 };
 */
 static char buf_asctime[2*3 + 5*INT_STRLEN_MAXIMUM(int) + 7 + 2 + 1 + 1];
 
-/* A similar buffer for ctime.
+/* On pre-C99 platforms, a snprintf substitute good enough for us.  */
-   C89 requires that they be the same buffer.
+#if !HAVE_SNPRINTF
-   This requirement was removed in C99, so support it only if requested,
+# include <stdarg.h>
-   as support is more likely to lead to bugs in badly written programs.  */
+ATTRIBUTE_FORMAT((printf, 3, 4)) static int
-#if SUPPORT_C89
+my_snprintf(char *s, size_t size, char const *format, ...)
-# define buf_ctime buf_asctime
+{
-#else
+  int n;
-static char buf_ctime[sizeof buf_asctime];
+  va_list args;
+  char stackbuf[sizeof buf_asctime];
+  va_start(args, format);
+  n = vsprintf(stackbuf, format, args);
+  va_end (args);
+  if (0 <= n && n < size)
+    memcpy (s, stackbuf, n + 1);
+  return n;
+}
+# undef snprintf
+# define snprintf my_snprintf
 #endif
 
 /* Publish asctime_r and ctime_r only when supporting older POSIX.  */
@@ -84,14 +74,19 @@ asctime_r(struct tm const *restrict timeptr, char *restrict buf)
 		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
 		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 	};
-	const char *	wn;
+	register const char *	wn;
-	const char *	mn;
+	register const char *	mn;
-	char			year[INT_STRLEN_MAXIMUM(int) + 2];
+	int year, mday, hour, min, sec;
-	char result[sizeof buf_asctime];
+	long long_TM_YEAR_BASE = TM_YEAR_BASE;
+	size_t bufsize = (buf == buf_asctime
+			  ? sizeof buf_asctime : STD_ASCTIME_BUF_SIZE);
 
 	if (timeptr == NULL) {
+		strcpy(buf, "??? ??? ?? ??:??:?? ????\n");
+		/* Set errno now, since strcpy might change it in
+		   POSIX.1-2017 and earlier.  */
 		errno = EINVAL;
-		return strcpy(buf, "??? ??? ?? ??:??:?? ????\n");
+		return buf;
 	}
 	if (timeptr->tm_wday < 0 || timeptr->tm_wday >= DAYSPERWEEK)
 		wn = "???";
@@ -99,25 +94,41 @@ asctime_r(struct tm const *restrict timeptr, char *restrict buf)
 	if (timeptr->tm_mon < 0 || timeptr->tm_mon >= MONSPERYEAR)
 		mn = "???";
 	else	mn = mon_name[timeptr->tm_mon];
-	/*
+
-	** Use strftime's %Y to generate the year, to avoid overflow problems
+	year = timeptr->tm_year;
-	** when computing timeptr->tm_year + TM_YEAR_BASE.
+	mday = timeptr->tm_mday;
-	** Assume that strftime is unaffected by other out-of-range members
+	hour = timeptr->tm_hour;
-	** (e.g., timeptr->tm_mday) when processing "%Y".
+	min = timeptr->tm_min;
-	*/
+	sec = timeptr->tm_sec;
-	strftime(year, sizeof year, "%Y", timeptr);
+
-	/*
+	/* Vintage programs are coded for years that are always four bytes long
-	** We avoid using snprintf since it's not available on all systems.
+	   and may assume that the newline always lands in the same place.
-	*/
+	   For years that are less than four bytes, pad the output with
-	sprintf(result,
+	   leading zeroes to get the newline in the traditional place.
-		((strlen(year) <= 4) ? ASCTIME_FMT : ASCTIME_FMT_B),
+	   For years longer than four bytes, put extra spaces before the year
-		wn, mn,
+	   so that vintage code trying to overwrite the newline
-		timeptr->tm_mday, timeptr->tm_hour,
+	   won't overwrite a digit within a year and truncate the year,
-		timeptr->tm_min, timeptr->tm_sec,
+	   using the principle that no output is better than wrong output.
-		year);
+	   This conforms to ISO C and POSIX standards, which say behavior
-	if (strlen(result) < STD_ASCTIME_BUF_SIZE
+	   is undefined when the year is less than 1000 or greater than 9999.
-	    || buf == buf_ctime || buf == buf_asctime)
+
-		return strcpy(buf, result);
+	   Also, avoid overflow when formatting tm_year + TM_YEAR_BASE.  */
+
+	if ((year <= LONG_MAX - TM_YEAR_BASE
+	     ? snprintf (buf, bufsize,
+			 ((-999 - TM_YEAR_BASE <= year
+			   && year <= 9999 - TM_YEAR_BASE)
+			  ? "%s %s%3d %.2d:%.2d:%.2d %04ld\n"
+			  : "%s %s%3d %.2d:%.2d:%.2d     %ld\n"),
+			 wn, mn, mday, hour, min, sec,
+			 year + long_TM_YEAR_BASE)
+	     : snprintf (buf, bufsize,
+			 "%s %s%3d %.2d:%.2d:%.2d     %d%d\n",
+			 wn, mn, mday, hour, min, sec,
+			 year / 10 + TM_YEAR_BASE / 10,
+			 year % 10))
+	    < bufsize)
+		return buf;
 	else {
 		errno = EOVERFLOW;
 		return NULL;
@@ -142,5 +153,8 @@ ctime_r(const time_t *timep, char *buf)
 char *
 ctime(const time_t *timep)
 {
-  return ctime_r(timep, buf_ctime);
+  /* Do not call localtime_r, as C23 requires ctime to initialize the
+     static storage that localtime updates.  */
+  struct tm *tmp = localtime(timep);
+  return tmp ? asctime(tmp) : NULL;
 }

contrib/tzcode/date.1

@@ -6,15 +6,13 @@ date \- show and set date and time
 .SH SYNOPSIS
 .if n .nh
 .if n .na
-.ie \n(.g .ds - \f(CR-\fP
-.el .ds - \-
 .B date
 [
-.B \*-u
+.B \-u
 ] [
-.B \*-c
+.B \-c
 ] [
-.B \*-r
+.B \-r
 .I seconds
 ] [
 .BI + format
@@ -35,7 +33,7 @@ command
 without arguments writes the date and time to the standard output in
 the form
 .ce 1
-Wed Mar  8 14:54:40 EST 1989
+Sat Mar  8 14:54:40 EST 2025
 .br
 with
 .B EST
@@ -49,99 +47,24 @@ If a command-line argument starts with a plus sign (\c
 .q "\fB+\fP" ),
 the rest of the argument is used as a
 .I format
-that controls what appears in the output.
+that is processed by
-In the format, when a percent sign (\c
+.BR strftime (3)
-.q "\fB%\fP"
+to determine what to output;
-appears,
+a newline character is appended.
-it and the character after it are not output,
+For example, the shell command:
-but rather identify part of the date or time
+.ce 1
-to be output in a particular way
+date +"%Y\-%m\-%d %H:%M:%S %z"
-(or identify a special character to output):
+.br
-.nf
+outputs a line like
-.sp
+.q "2025\-03\-08 14:54:40 \-0500"
-.if t .in +.5i
+instead.
-.if n .in +2
-.ta \w'%M\0\0'u +\w'Wed Mar  8 14:54:40 EST 1989\0\0'u
-	Sample output	Explanation
-%a	Wed	Abbreviated weekday name*
-%A	Wednesday	Full weekday name*
-%b	Mar	Abbreviated month name*
-%B	March	Full month name*
-%c	Wed Mar 08 14:54:40 1989	Date and time*
-%C	19	Century
-%d	08	Day of month (always two digits)
-%D	03/08/89	Month/day/year (eight characters)
-%e	 8	Day of month (leading zero blanked)
-%h	Mar	Abbreviated month name*
-%H	14	24-hour-clock hour (two digits)
-%I	02	12-hour-clock hour (two digits)
-%j	067	Julian day number (three digits)
-%k	 2	12-hour-clock hour (leading zero blanked)
-%l	14	24-hour-clock hour (leading zero blanked)
-%m	03	Month number (two digits)
-%M	54	Minute (two digits)
-%n	\\n	newline character
-%p	PM	AM/PM designation
-%r	02:54:40 PM	Hour:minute:second AM/PM designation
-%R	14:54	Hour:minute
-%S	40	Second (two digits)
-%t	\\t	tab character
-%T	14:54:40	Hour:minute:second
-%U	10	Sunday-based week number (two digits)
-%w	3	Day number (one digit, Sunday is 0)
-%W	10	Monday-based week number (two digits)
-%x	03/08/89	Date*
-%X	14:54:40	Time*
-%y	89	Last two digits of year
-%Y	1989	Year in full
-%z	-0500	Numeric time zone
-%Z	EST	Time zone abbreviation
-%+	Wed Mar  8 14:54:40 EST 1989	Default output format*
-.if t .in -.5i
-.if n .in -2
-* The exact output depends on the locale.
-.sp
-.fi
-If a character other than one of those shown above appears after
-a percent sign in the format,
-that following character is output.
-All other characters in the format are copied unchanged to the output;
-a newline character is always added at the end of the output.
-.PP
-In Sunday-based week numbering,
-the first Sunday of the year begins week 1;
-days preceding it are part of
-.q "week 0" .
-In Monday-based week numbering,
-the first Monday of the year begins week 1.
-.PP
-To set the date, use a command line argument with one of the following forms:
-.nf
-.if t .in +.5i
-.if n .in +2
-.ta \w'198903081454\0'u
-1454	24-hour-clock hours (first two digits) and minutes
-081454	Month day (first two digits), hours, and minutes
-03081454	Month (two digits, January is 01), month day, hours, minutes
-8903081454	Year, month, month day, hours, minutes
-0308145489	Month, month day, hours, minutes, year
-	(on System V-compatible systems)
-030814541989	Month, month day, hours, minutes, four-digit year
-198903081454	Four-digit year, month, month day, hours, minutes
-.if t .in -.5i
-.if n .in -2
-.fi
-If the century, year, month, or month day is not given,
-the current value is used.
-Any of the above forms may be followed by a period and two digits that give
-the seconds part of the new time; if no seconds are given, zero is assumed.
 .PP
 These options are available:
 .TP
-.BR \*-u " or " \*-c
+.BR \-u " or " \-c
 Use Universal Time when setting and showing the date and time.
 .TP
-.BI "\*-r " seconds
+.BI "\-r " seconds
 Output the date that corresponds to
 .I seconds
 past the epoch of 1970-01-01 00:00:00 UTC, where
@@ -149,16 +72,13 @@ past the epoch of 1970-01-01 00:00:00 UTC, where
 should be an integer, either decimal, octal (leading 0), or
 hexadecimal (leading 0x), preceded by an optional sign.
 .SH FILES
-.ta \w'/usr/share/zoneinfo/posixrules\0\0'u
+.ta \w'/usr/share/zoneinfo/Etc/UTC\0\0'u
 /etc/localtime	local timezone file
 .br
 /usr/lib/locale/\f2L\fP/LC_TIME	description of time locale \f2L\fP
 .br
 /usr/share/zoneinfo	timezone directory
 .br
-/usr/share/zoneinfo/posixrules	default DST rules (obsolete)
+/usr/share/zoneinfo/Etc/UTC	for UTC leap seconds
-.br
+.SH SEE ALSO
-/usr/share/zoneinfo/GMT	for UTC leap seconds
+.BR strftime (3).
-.PP
-If /usr/share/zoneinfo/GMT is absent,
-UTC leap seconds are loaded from /usr/share/zoneinfo/GMT0 if present.

contrib/tzcode/newctime.3

@@ -5,43 +5,34 @@
 asctime, ctime, difftime, gmtime, localtime, mktime \- convert date and time
 .SH SYNOPSIS
 .nf
-.ie \n(.g .ds - \f(CR-\fP
-.el .ds - \-
 .B #include <time.h>
 .PP
-.B [[deprecated]] char *ctime(time_t const *clock);
-.PP
-/* Only in POSIX.1-2017 and earlier.  */
-.B char *ctime_r(time_t const *clock, char *buf);
-.PP
-.B double difftime(time_t time1, time_t time0);
-.PP
-.B [[deprecated]] char *asctime(struct tm const *tm);
-.PP
-/* Only in POSIX.1-2017 and earlier.  */
-.B "char *asctime_r(struct tm const *restrict tm,"
-.B "    char *restrict result);"
-.PP
 .B struct tm *localtime(time_t const *clock);
-.PP
 .B "struct tm *localtime_r(time_t const *restrict clock,"
 .B "    struct tm *restrict result);"
-.PP
 .B "struct tm *localtime_rz(timezone_t restrict zone,"
 .B "    time_t const *restrict clock,"
 .B "    struct tm *restrict result);"
 .PP
 .B struct tm *gmtime(time_t const *clock);
-.PP
 .B "struct tm *gmtime_r(time_t const *restrict clock,"
 .B "    struct tm *restrict result);"
 .PP
 .B time_t mktime(struct tm *tm);
-.PP
 .B "time_t mktime_z(timezone_t restrict zone,"
 .B "    struct tm *restrict tm);"
 .PP
-.B cc ... \*-ltz
+.B double difftime(time_t time1, time_t time0);
+.PP
+.B [[deprecated]] char *asctime(struct tm const *tm);
+.B [[deprecated]] char *ctime(time_t const *clock);
+.PP
+/* Only in POSIX.1-2017 and earlier.  */
+.B char *ctime_r(time_t const *clock, char *buf);
+.B "char *asctime_r(struct tm const *restrict tm,"
+.B "    char *restrict result);"
+.PP
+.B cc ... \-ltz
 .fi
 .SH DESCRIPTION
 .ie '\(en'' .ds en \-
@@ -54,30 +45,26 @@ asctime, ctime, difftime, gmtime, localtime, mktime \- convert date and time
 \\$3\*(lq\\$1\*(rq\\$2
 ..
 The
-.B ctime
+.B localtime
-function
+and
-converts a long integer, pointed to by
+.B gmtime
+functions
+convert an integer, pointed to by
 .IR clock ,
-and returns a pointer to a
+and
-string of the form
+return pointers to
-.br
+.q "tm"
-.ce
+structures, described below.
-.eo
+If the integer is out of range for conversion,
-Thu Nov 24 18:22:48 1986\n\0
+these functions return a null pointer.
-.br
+The
-.ec
+.B localtime
-Years requiring fewer than four characters are padded with leading zeroes.
+function
-For years longer than four characters, the string is of the form
+corrects for the time zone and any time zone adjustments
-.br
+(such as Daylight Saving Time in the United States).
-.ce
+The
-.eo
+.B gmtime
-Thu Nov 24 18:22:48     81986\n\0
+function converts to Coordinated Universal Time.
-.ec
-.br
-with five spaces before the year.
-These unusual formats are designed to make it less likely that older
-software that expects exactly 26 bytes of output will mistakenly output
-misleading values for out-of-range years.
 .PP
 The
 .BI * clock
@@ -91,47 +78,6 @@ introduction of UTC and are some other flavor of Universal Time (UT).
 Some implementations support leap seconds, in contradiction to POSIX.
 .PP
 The
-.B ctime
-function is deprecated starting in C23.
-Callers can use
-.B localtime_r
-and
-.B strftime
-instead.
-.PP
-The
-.B localtime
-and
-.B gmtime
-functions
-return pointers to
-.q "tm"
-structures, described below.
-The
-.B localtime
-function
-corrects for the time zone and any time zone adjustments
-(such as Daylight Saving Time in the United States).
-.PP
-The
-.B gmtime
-function
-converts to Coordinated Universal Time.
-.PP
-The
-.B asctime
-function
-converts a time value contained in a
-.q "tm"
-structure to a string,
-as shown in the above example,
-and returns a pointer to the string.
-This function is deprecated starting in C23.
-Callers can use
-.B strftime
-instead.
-.PP
-The
 .B mktime
 function
 converts the broken-down time,
@@ -204,6 +150,52 @@ returns the difference between two calendar times,
 expressed in seconds.
 .PP
 The
+.B asctime
+function
+converts a time value contained in a
+.q "tm"
+structure to a pointer to a
+string of the form
+.br
+.ce
+.eo
+Thu Nov 24 18:22:48 1986\n\0
+.br
+.ec
+Years requiring fewer than four characters are padded with leading zeroes.
+For years longer than four characters, the string is of the form
+.br
+.ce
+.eo
+Thu Nov 24 18:22:48     81986\n\0
+.ec
+.br
+with five spaces before the year.
+This unusual format is designed to make it less likely that older
+software that expects exactly 26 bytes of output will mistakenly output
+misleading values for out-of-range years.
+This function is deprecated starting in C23.
+Callers can use
+.B strftime
+instead.
+.PP
+The
+.B ctime
+function is equivalent to calliing
+.B localtime
+and then calling
+.B asctime
+on the result.
+Like
+.BR asctime ,
+this function is deprecated starting in C23.
+Callers can use
+.B localtime
+and
+.B strftime
+instead.
+.PP
+The
 .BR ctime_r ,
 .BR localtime_r ,
 .BR gmtime_r ,

contrib/tzcode/newstrftime.3

@@ -40,8 +40,6 @@
 strftime \- format date and time
 .SH SYNOPSIS
 .nf
-.ie \n(.g .ds - \f(CR-\fP
-.el .ds - \-
 .B #include <time.h>
 .PP
 .B "size_t strftime(char *restrict buf, size_t maxsize,"
@@ -93,7 +91,7 @@ If a bracketed member name is followed by
 .B strftime
 can use the named member even though POSIX.1-2024 does not list it;
 if the name is followed by
-.q \*- ,
+.q \- ,
 .B strftime
 ignores the member even though POSIX.1-2024 lists it
 which means portable code should set it.
@@ -139,11 +137,14 @@ is replaced by the locale's appropriate date and time representation.
 .IR tm_sec ,
 .IR tm_gmtoff ,
 .IR tm_zone ,
-.IR tm_isdst \*-].
+.IR tm_isdst \-].
 .TP
 %D
 is equivalent to
 .c %m/%d/%y .
+Although used in the United States for current dates,
+this format is ambiguous elsewhere
+and for dates that might involve other centuries.
 .RI [ tm_year ,
 .IR tm_mon ,
 .IR tm_mday ]
@@ -167,6 +168,8 @@ is equivalent to
 .TP
 %G
 is replaced by the ISO 8601 year with century as a decimal number.
+This is the year that includes the greater part of the week.
+(Monday as the first day of a week).
 See also the
 .c %V
 conversion specification.
@@ -176,11 +179,7 @@ conversion specification.
 .TP
 %g
 is replaced by the ISO 8601 year without century as a decimal number [00,99].
-This is the year that includes the greater part of the week.
+Since it omits the century, it is ambiguous for dates.
-(Monday as the first day of a week).
-See also the
-.c %V
-conversion specification.
 .RI [ tm_year ,
 .IR tm_yday ,
 .IR tm_wday ]
@@ -249,9 +248,22 @@ of leap seconds.
 is replaced by the number of seconds since the Epoch (see
 .BR ctime (3)).
 Although %s is reliable in this implementation,
-it can have glitches on other platforms (notably platforms lacking
+it can have glitches on other platforms
-.IR tm_gmtoff ),
+(notably obsolescent platforms lacking
-so portable code should format a
+.I tm_gmtoff
+or where
+.B time_t
+is no wider than int), and POSIX allows
+.B strftime
+to set
+.B errno
+to
+.B EINVAL
+or
+.B EOVERFLOW
+and return 0 if the number of seconds would be negative or out of range for
+.BR time_t .
+Portable code should therefore format a
 .B time_t
 value directly via something like
 .B sprintf
@@ -267,7 +279,7 @@ with "%s".
 .IR tm_min ,
 .IR tm_sec ,
 .IR tm_gmtoff +,
-.IR tm_isdst \*-].
+.IR tm_isdst \-].
 .TP
 %T
 is replaced by the time in the format
@@ -284,7 +296,7 @@ is replaced by the week number of the year (Sunday as the first day of
 the week) as a decimal number [00,53].
 .RI [ tm_wday ,
 .IR tm_yday ,
-.IR tm_year \*-]
+.IR tm_year \-]
 .TP
 %u
 is replaced by the weekday (Monday as the first day of the week)
@@ -318,31 +330,33 @@ as a decimal number [0,6].
 .TP
 %X
 is replaced by the locale's appropriate time representation.
-.RI [ tm_year \*-,
+.RI [ tm_year \-,
-.IR tm_yday \*-,
+.IR tm_yday \-,
-.IR tm_mon \*-,
+.IR tm_mon \-,
-.IR tm_mday \*-,
+.IR tm_mday \-,
-.IR tm_wday \*-,
+.IR tm_wday \-,
 .IR tm_hour ,
 .IR tm_min ,
 .IR tm_sec ,
 .IR tm_gmtoff ,
 .IR tm_zone ,
-.IR tm_isdst \*-].
+.IR tm_isdst \-].
 .TP
 %x
 is replaced by the locale's appropriate date representation.
+This format can be ambiguous for dates, e.g.,
+it can generate "01/02/03" in the C locale.
 .RI [ tm_year ,
 .IR tm_yday ,
 .IR tm_mon ,
 .IR tm_mday ,
 .IR tm_wday ,
-.IR tm_hour \*-,
+.IR tm_hour \-,
-.IR tm_min \*-,
+.IR tm_min \-,
-.IR tm_sec \*-,
+.IR tm_sec \-,
-.IR tm_gmtoff \*-,
+.IR tm_gmtoff \-,
-.IR tm_zone \*-,
+.IR tm_zone \-,
-.IR tm_isdst \*-].
+.IR tm_isdst \-].
 .TP
 %Y
 is replaced by the year with century as a decimal number.
@@ -350,28 +364,29 @@ is replaced by the year with century as a decimal number.
 .TP
 %y
 is replaced by the year without century as a decimal number [00,99].
+Since it omits the century, it is ambiguous for dates.
 .RI [ tm_year ]
 .TP
 %Z
 is replaced by the time zone abbreviation,
 or by the empty string if this is not determinable.
 .RI [ tm_zone ,
-.IR tm_isdst \*-]
+.IR tm_isdst \-]
 .TP
 %z
 is replaced by the offset from the Prime Meridian
-in the format +HHMM or \*-HHMM (ISO 8601) as appropriate,
+in the format +HHMM or \-HHMM (ISO 8601) as appropriate,
 with positive values representing locations east of Greenwich,
 or by the empty string if this is not determinable.
-The numeric time zone abbreviation \*-0000 is used when the time is
+The numeric time zone abbreviation \-0000 is used when the time is
 Universal Time
 but local time is indeterminate; by convention this is used for
 locations while uninhabited, and corresponds to a zero offset when the
 time zone abbreviation begins with
-.q "\*-" .
+.q "\-" .
 .RI [ tm_gmtoff ,
 .IR tm_zone +,
-.IR tm_isdst \*-]
+.IR tm_isdst \-]
 .TP
 %%
 is replaced by a single %.
@@ -418,15 +433,6 @@ This function fails if:
 The total number of resulting bytes, including the terminating
 NUL character, is more than
 .IR maxsize .
-.PP
-This function may fail if:
-.TP
-[EOVERFLOW]
-The format includes an
-.c %s
-conversion and the number of seconds since the Epoch cannot be represented
-in a
-.c time_t .
 .SH SEE ALSO
 .BR date (1),
 .BR getenv (3),

contrib/tzcode/newtzset.3

@@ -5,8 +5,6 @@
 tzset \- initialize time conversion information
 .SH SYNOPSIS
 .nf
-.ie \n(.g .ds - \f(CR-\fP
-.el .ds - \-
 .B #include <time.h>
 .PP
 .BI "timezone_t tzalloc(char const *" TZ );
@@ -23,7 +21,7 @@ tzset \- initialize time conversion information
 .br
 .B extern int daylight;
 .PP
-.B cc ... \*-ltz
+.B cc ... \-ltz
 .fi
 .SH DESCRIPTION
 .ie '\(en'' .ds en \-
@@ -110,7 +108,7 @@ except a leading colon
 digits, comma
 .RB ( , ),
 ASCII minus
-.RB ( \*- ),
+.RB ( \- ),
 ASCII plus
 .RB ( + ),
 and NUL bytes are allowed.
@@ -150,7 +148,7 @@ daylight saving time is assumed to be one hour ahead of standard time.  One or
 more digits may be used; the value is always interpreted as a decimal
 number.  The hour must be between zero and 24, and the minutes (and
 seconds) \*(en if present \*(en between zero and 59.  If preceded by a
-.q "\*-" ,
+.q "\-" ,
 the time zone shall be east of the Prime Meridian; otherwise it shall be
 west (which may be indicated by an optional preceding
 .q "+" .
@@ -239,7 +237,7 @@ values that directly specify the timezone.
 stands for US Eastern Standard
 Time (EST), 5 hours behind UT, without daylight saving.
 .TP
-.B <+12>\*-12<+13>,M11.1.0,M1.2.1/147
+.B <+12>\-12<+13>,M11.1.0,M1.2.1/147
 stands for Fiji time, 12 hours ahead
 of UT, springing forward on November's first Sunday at 02:00, and
 falling back on January's second Monday at 147:00 (i.e., 03:00 on the
@@ -249,34 +247,34 @@ and daylight saving time are
 and
 .q "+13".
 .TP
-.B IST\*-2IDT,M3.4.4/26,M10.5.0
+.B IST\-2IDT,M3.4.4/26,M10.5.0
 stands for Israel Standard Time (IST) and Israel Daylight Time (IDT),
 2 hours ahead of UT, springing forward on March's fourth
 Thursday at 26:00 (i.e., 02:00 on the first Friday on or after March
 23), and falling back on October's last Sunday at 02:00.
 .TP
-.B <\*-04>4<\*-03>,J1/0,J365/25
+.B <\-04>4<\-03>,J1/0,J365/25
 stands for permanent daylight saving time, 3 hours behind UT with
 abbreviation
-.q "\*-03".
+.q "\-03".
 There is a dummy fall-back transition on December 31 at 25:00 daylight
 saving time (i.e., 24:00 standard time, equivalent to January 1 at
 00:00 standard time), and a simultaneous spring-forward transition on
 January 1 at 00:00 standard time, so daylight saving time is in effect
 all year and the initial
-.B <\*-04>
+.B <\-04>
 is a placeholder.
 .TP
-.B <\*-03>3<\*-02>,M3.5.0/\*-2,M10.5.0/\*-1
+.B <\-03>3<\-02>,M3.5.0/\-2,M10.5.0/\-1
 stands for time in western Greenland, 3 hours behind UT, where clocks
 follow the EU rules of
 springing forward on March's last Sunday at 01:00 UT (\-02:00 local
 time, i.e., 22:00 the previous day) and falling back on October's last
 Sunday at 01:00 UT (\-01:00 local time, i.e., 23:00 the previous day).
 The abbreviations for standard and daylight saving time are
-.q "\*-03"
+.q "\-03"
 and
-.q "\*-02".
+.q "\-02".
 .PP
 If
 .I TZ

contrib/tzcode/private.h

@@ -37,6 +37,38 @@
 # define SUPPORT_C89 1
 #endif
 
+
+/* The following feature-test macros should be defined before
+   any #include of a system header.  */
+
+/* Enable tm_gmtoff, tm_zone, and environ on GNUish systems.  */
+#define _GNU_SOURCE 1
+/* Fix asctime_r on Solaris 11.  */
+#define _POSIX_PTHREAD_SEMANTICS 1
+/* Enable strtoimax on pre-C99 Solaris 11.  */
+#define __EXTENSIONS__ 1
+/* Cause MS-Windows headers to define POSIX names.  */
+#define _CRT_DECLARE_NONSTDC_NAMES 1
+/* Prevent MS-Windows headers from defining min and max.  */
+#define NOMINMAX 1
+
+/* On GNUish systems where time_t might be 32 or 64 bits, use 64.
+   On these platforms _FILE_OFFSET_BITS must also be 64; otherwise
+   setting _TIME_BITS to 64 does not work.  The code does not
+   otherwise rely on _FILE_OFFSET_BITS being 64, since it does not
+   use off_t or functions like 'stat' that depend on off_t.  */
+#ifndef _TIME_BITS
+# ifndef _FILE_OFFSET_BITS
+#  define _FILE_OFFSET_BITS 64
+# endif
+# if _FILE_OFFSET_BITS == 64
+#  define _TIME_BITS 64
+# endif
+#endif
+
+/* End of feature-test macro definitions.  */
+
+
 #ifndef __STDC_VERSION__
 # define __STDC_VERSION__ 0
 #endif
@@ -51,6 +83,7 @@
 #endif
 
 #if __STDC_VERSION__ < 202311
+# undef static_assert
 # define static_assert(cond) extern int static_assert_check[(cond) ? 1 : -1]
 #endif
 
@@ -87,11 +120,11 @@
 
 #if !defined HAVE_GETTEXT && defined __has_include
 # if __has_include(<libintl.h>)
-#  define HAVE_GETTEXT true
+#  define HAVE_GETTEXT 1
 # endif
 #endif
 #ifndef HAVE_GETTEXT
-# define HAVE_GETTEXT false
+# define HAVE_GETTEXT 0
 #endif
 
 #ifndef HAVE_INCOMPATIBLE_CTIME_R
@@ -124,20 +157,20 @@
 
 #if !defined HAVE_SYS_STAT_H && defined __has_include
 # if !__has_include(<sys/stat.h>)
-#  define HAVE_SYS_STAT_H false
+#  define HAVE_SYS_STAT_H 0
 # endif
 #endif
 #ifndef HAVE_SYS_STAT_H
-# define HAVE_SYS_STAT_H true
+# define HAVE_SYS_STAT_H 1
 #endif
 
 #if !defined HAVE_UNISTD_H && defined __has_include
 # if !__has_include(<unistd.h>)
-#  define HAVE_UNISTD_H false
+#  define HAVE_UNISTD_H 0
 # endif
 #endif
 #ifndef HAVE_UNISTD_H
-# define HAVE_UNISTD_H true
+# define HAVE_UNISTD_H 1
 #endif
 
 #ifndef NETBSD_INSPIRED
@@ -149,25 +182,6 @@
 # define ctime_r _incompatible_ctime_r
 #endif /* HAVE_INCOMPATIBLE_CTIME_R */
 
-/* Enable tm_gmtoff, tm_zone, and environ on GNUish systems.  */
-#define _GNU_SOURCE 1
-/* Fix asctime_r on Solaris 11.  */
-#define _POSIX_PTHREAD_SEMANTICS 1
-/* Enable strtoimax on pre-C99 Solaris 11.  */
-#define __EXTENSIONS__ 1
-
-/* On GNUish systems where time_t might be 32 or 64 bits, use 64.
-   On these platforms _FILE_OFFSET_BITS must also be 64; otherwise
-   setting _TIME_BITS to 64 does not work.  The code does not
-   otherwise rely on _FILE_OFFSET_BITS being 64, since it does not
-   use off_t or functions like 'stat' that depend on off_t.  */
-#ifndef _FILE_OFFSET_BITS
-# define _FILE_OFFSET_BITS 64
-#endif
-#if !defined _TIME_BITS && _FILE_OFFSET_BITS == 64
-# define _TIME_BITS 64
-#endif
-
 /*
 ** Nested includes
 */
@@ -260,6 +274,10 @@
 # endif
 #endif
 
+#ifndef HAVE_SNPRINTF
+# define HAVE_SNPRINTF (!PORT_TO_C89 || 199901 <= __STDC_VERSION__)
+#endif
+
 #ifndef HAVE_STRFTIME_L
 # if _POSIX_VERSION < 200809
 #  define HAVE_STRFTIME_L 0
@@ -305,7 +323,7 @@
 ** stdint.h, even with pre-C99 compilers.
 */
 #if !defined HAVE_STDINT_H && defined __has_include
-# define HAVE_STDINT_H true /* C23 __has_include implies C99 stdint.h.  */
+# define HAVE_STDINT_H 1 /* C23 __has_include implies C99 stdint.h.  */
 #endif
 #ifndef HAVE_STDINT_H
 # define HAVE_STDINT_H \
@@ -375,11 +393,15 @@ typedef int int_fast32_t;
 # endif
 #endif
 
+#ifndef INT_LEAST32_MAX
+typedef int_fast32_t int_least32_t;
+#endif
+
 #ifndef INTMAX_MAX
 # ifdef LLONG_MAX
 typedef long long intmax_t;
 #  ifndef HAVE_STRTOLL
-#   define HAVE_STRTOLL true
+#   define HAVE_STRTOLL 1
 #  endif
 #  if HAVE_STRTOLL
 #   define strtoimax strtoll
@@ -459,7 +481,7 @@ typedef unsigned long uintmax_t;
    hosts, unless compiled with -DHAVE_STDCKDINT_H=0 or with pre-C23 EDG.  */
 #if !defined HAVE_STDCKDINT_H && defined __has_include
 # if __has_include(<stdckdint.h>)
-#  define HAVE_STDCKDINT_H true
+#  define HAVE_STDCKDINT_H 1
 # endif
 #endif
 #ifdef HAVE_STDCKDINT_H
@@ -554,13 +576,26 @@ typedef unsigned long uintmax_t;
 # define ATTRIBUTE_REPRODUCIBLE /* empty */
 #endif
 
+#if HAVE___HAS_C_ATTRIBUTE
+# if __has_c_attribute(unsequenced)
+#  define ATTRIBUTE_UNSEQUENCED [[unsequenced]]
+# endif
+#endif
+#ifndef ATTRIBUTE_UNSEQUENCED
+# define ATTRIBUTE_UNSEQUENCED /* empty */
+#endif
+
 /* GCC attributes that are useful in tzcode.
+   __attribute__((const)) is stricter than [[unsequenced]],
+   so the latter is an adequate substitute in non-GCC C23 platforms.
    __attribute__((pure)) is stricter than [[reproducible]],
    so the latter is an adequate substitute in non-GCC C23 platforms.  */
 #if __GNUC__ < 3
+# define ATTRIBUTE_CONST ATTRIBUTE_UNSEQUENCED
 # define ATTRIBUTE_FORMAT(spec) /* empty */
 # define ATTRIBUTE_PURE ATTRIBUTE_REPRODUCIBLE
 #else
+# define ATTRIBUTE_CONST __attribute__((const))
 # define ATTRIBUTE_FORMAT(spec) __attribute__((format spec))
 # define ATTRIBUTE_PURE __attribute__((pure))
 #endif
@@ -593,6 +628,12 @@ typedef unsigned long uintmax_t;
 # define RESERVE_STD_EXT_IDS 0
 #endif
 
+#ifdef time_tz
+# define defined_time_tz true
+#else
+# define defined_time_tz false
+#endif
+
 /* If standard C identifiers with external linkage (e.g., localtime)
    are reserved and are not already being renamed anyway, rename them
    as if compiling with '-Dtime_tz=time_t'.  */
@@ -608,9 +649,9 @@ typedef unsigned long uintmax_t;
 ** typical platforms.
 */
 #if defined time_tz || EPOCH_LOCAL || EPOCH_OFFSET != 0
-# define TZ_TIME_T 1
+# define TZ_TIME_T true
 #else
-# define TZ_TIME_T 0
+# define TZ_TIME_T false
 #endif
 
 #if defined LOCALTIME_IMPLEMENTATION && TZ_TIME_T
@@ -707,7 +748,7 @@ DEPRECATED_IN_C23 char *ctime(time_t const *);
 char *asctime_r(struct tm const *restrict, char *restrict);
 char *ctime_r(time_t const *, char *);
 #endif
-double difftime(time_t, time_t);
+ATTRIBUTE_CONST double difftime(time_t, time_t);
 size_t strftime(char *restrict, size_t, char const *restrict,
 		struct tm const *restrict);
 # if HAVE_STRFTIME_L
@@ -729,9 +770,9 @@ void tzset(void);
       || defined __GLIBC__ || defined __tm_zone /* musl */ \
       || defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__ \
       || (defined __APPLE__ && defined __MACH__))
-#  define HAVE_DECL_TIMEGM true
+#  define HAVE_DECL_TIMEGM 1
 # else
-#  define HAVE_DECL_TIMEGM false
+#  define HAVE_DECL_TIMEGM 0
 # endif
 #endif
 #if !HAVE_DECL_TIMEGM && !defined timegm
@@ -771,7 +812,11 @@ extern long altzone;
 */
 
 #ifndef STD_INSPIRED
-# define STD_INSPIRED 0
+# ifdef __NetBSD__
+#  define STD_INSPIRED 1
+# else
+#  define STD_INSPIRED 0
+# endif
 #endif
 #if STD_INSPIRED
 # if TZ_TIME_T || !defined offtime
@@ -880,7 +925,7 @@ ATTRIBUTE_PURE time_t time2posix_z(timezone_t, time_t);
 		default: TIME_T_MAX_NO_PADDING)			    \
      : (time_t) -1)
 enum { SIGNED_PADDING_CHECK_NEEDED
-         = _Generic((time_t) 0,
+	 = _Generic((time_t) 0,
 		    signed char: false, short: false,
 		    int: false, long: false, long long: false,
 		    default: true) };
@@ -927,8 +972,8 @@ static_assert(! TYPE_SIGNED(time_t) || ! SIGNED_PADDING_CHECK_NEEDED
 # define UNINIT_TRAP 0
 #endif
 
-/* localtime.c sometimes needs access to timeoff if it is not already public.
+/* strftime.c sometimes needs access to timeoff if it is not already public.
-   tz_private_timeoff should be used only by localtime.c.  */
+   tz_private_timeoff should be used only by localtime.c and strftime.c.  */
 #if (!defined EXTERN_TIMEOFF \
      && defined TM_GMTOFF && (200809 < _POSIX_VERSION || ! UNINIT_TRAP))
 # ifndef timeoff

contrib/tzcode/strftime.c

@@ -39,8 +39,63 @@
 #include <locale.h>
 #include <stdio.h>
 
+/* If true, the value returned by an idealized unlimited-range mktime
+   always fits into an integer type with bounds MIN and MAX.
+   If false, the value might not fit.
+   This macro is usable in #if if its arguments are.
+   Add or subtract 2**31 - 1 for the maximum UT offset allowed in a TZif file,
+   divide by the maximum number of non-leap seconds in a year,
+   divide again by two just to be safe,
+   and account for the tm_year origin (1900) and time_t origin (1970).  */
+#define MKTIME_FITS_IN(min, max) \
+  ((min) < 0 \
+   && ((min) + 0x7fffffff) / 366 / 24 / 60 / 60 / 2 + 1970 - 1900 < INT_MIN \
+   && INT_MAX < ((max) - 0x7fffffff) / 366 / 24 / 60 / 60 / 2 + 1970 - 1900)
+
+/* MKTIME_MIGHT_OVERFLOW is true if mktime can fail due to time_t overflow
+   or if it is not known whether mktime can fail,
+   and is false if mktime definitely cannot fail.
+   This macro is usable in #if, and so does not use TIME_T_MAX or sizeof.
+   If the builder has not configured this macro, guess based on what
+   known platforms do.  When in doubt, guess true.  */
+#ifndef MKTIME_MIGHT_OVERFLOW
+# if defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__
+#  include <sys/param.h>
+# endif
+# if ((/* The following heuristics assume native time_t.  */ \
+       defined_time_tz) \
+      || ((/* Traditional time_t is 'long', so if 'long' is not wide enough \
+	      assume overflow unless we're on a known-safe host.  */ \
+	   !MKTIME_FITS_IN(LONG_MIN, LONG_MAX)) \
+	  && (/* GNU C Library 2.29 (2019-02-01) and later has 64-bit time_t \
+		 if __TIMESIZE is 64.  */ \
+	      !defined __TIMESIZE || __TIMESIZE < 64) \
+	  && (/* FreeBSD 12 r320347 (__FreeBSD_version 1200036; 2017-06-26), \
+		 and later has 64-bit time_t on all platforms but i386 which \
+		 is currently scheduled for end-of-life on 2028-11-30.  */ \
+	      !defined __FreeBSD_version || __FreeBSD_version < 1200036 \
+	      || defined __i386) \
+	  && (/* NetBSD 6.0 (2012-10-17) and later has 64-bit time_t.  */ \
+	      !defined __NetBSD_Version__ || __NetBSD_Version__ < 600000000) \
+	  && (/* OpenBSD 5.5 (2014-05-01) and later has 64-bit time_t.  */ \
+	      !defined OpenBSD || OpenBSD < 201405)))
+#  define MKTIME_MIGHT_OVERFLOW 1
+# else
+#  define MKTIME_MIGHT_OVERFLOW 0
+# endif
+#endif
+/* Check that MKTIME_MIGHT_OVERFLOW is consistent with time_t's range.  */
+static_assert(MKTIME_MIGHT_OVERFLOW
+	      || MKTIME_FITS_IN(TIME_T_MIN, TIME_T_MAX));
+
+#if MKTIME_MIGHT_OVERFLOW
+/* Do this after system includes as it redefines time_t, mktime, timeoff.  */
+# define USE_TIMEX_T true
+# include "localtime.c"
+#endif
+
 #ifndef DEPRECATE_TWO_DIGIT_YEARS
-# define DEPRECATE_TWO_DIGIT_YEARS false
+# define DEPRECATE_TWO_DIGIT_YEARS 0
 #endif
 
 struct lc_time_T {
@@ -135,10 +190,6 @@ strftime(char *restrict s, size_t maxsize, char const *restrict format,
 
 	tzset();
 	p = _fmt(format, t, s, s + maxsize, &warn);
-	if (!p) {
-	  errno = EOVERFLOW;
-	  return 0;
-	}
 	if (DEPRECATE_TWO_DIGIT_YEARS
 	    && warn != IN_NONE && getenv(YEAR_2000_NAME)) {
 		fprintf(stderr, "\n");
@@ -170,7 +221,12 @@ _fmt(const char *format, const struct tm *t, char *pt,
 		if (*format == '%') {
 label:
 			switch (*++format) {
-			case '\0':
+			default:
+				/* Output unknown conversion specifiers as-is,
+				   to aid debugging.  This includes '%' at
+				   format end.  This conforms to C23 section
+				   7.29.3.5 paragraph 6, which says behavior
+				   is undefined here.  */
 				--format;
 				break;
 			case 'A':
@@ -327,16 +383,17 @@ _fmt(const char *format, const struct tm *t, char *pt,
 					tm.tm_mday = t->tm_mday;
 					tm.tm_mon = t->tm_mon;
 					tm.tm_year = t->tm_year;
+
+					/* Get the time_t value for TM.
+					   Native time_t, or its redefinition
+					   by localtime.c above, is wide enough
+					   so that this cannot overflow.  */
 #ifdef TM_GMTOFF
 					mkt = timeoff(&tm, t->TM_GMTOFF);
 #else
 					tm.tm_isdst = t->tm_isdst;
 					mkt = mktime(&tm);
 #endif
-					/* If mktime fails, %s expands to the
-					   value of (time_t) -1 as a failure
-					   marker; this is better in practice
-					   than strftime failing.  */
 					if (TYPE_SIGNED(time_t)) {
 					  intmax_t n = mkt;
 					  sprintf(buf, "%"PRIdMAX, n);
@@ -590,12 +647,6 @@ _fmt(const char *format, const struct tm *t, char *pt,
 					warnp);
 				continue;
 			case '%':
-			/*
-			** X311J/88-090 (4.12.3.5): if conversion char is
-			** undefined, behavior is undefined. Print out the
-			** character itself as printf(3) also does.
-			*/
-			default:
 				break;
 			}
 		}

contrib/tzcode/theory.html

@@ -123,8 +123,9 @@ If geolocation information is available, a selection interface can
 locate the user on a timezone map or prioritize names that are
 geographically close. For an example selection interface, see the
 <code>tzselect</code> program in the <code><abbr>tz</abbr></code> code.
-The <a href="https://cldr.unicode.org">Unicode Common Locale Data
+Unicode's <a href="https://cldr.unicode.org">Common Locale Data
-Repository</a> contains data that may be useful for other selection
+Repository (<abbr>CLDR</abbr>)</a>
+contains data that may be useful for other selection
 interfaces; it maps timezone names like <code>Europe/Prague</code> to
 locale-dependent strings like "Prague", "Praha", "Прага", and "布拉格".
 </p>
@@ -200,6 +201,8 @@ in decreasing order of importance:
   <li>
     A name must not be empty, or contain '<code>//</code>', or
     start or end with '<code>/</code>'.
+    Also, a name must not be '<code>Etc/Unknown</code>', as
+    <abbr>CLDR</abbr> uses that string for an unknown or invalid timezone.
   </li>
   <li>
     Do not use names that differ only in case.
@@ -220,10 +223,18 @@ in decreasing order of importance:
     do not need locations, since local time is not defined there.
   </li>
   <li>
-    If all the clocks in a timezone have agreed since 1970,
+    If all clocks in a region have agreed since 1970,
-    do not bother to include more than one timezone
+    give them just one name even if some of the clocks disagreed before 1970,
-    even if some of the clocks disagreed before 1970.
+    or reside in different countries or in notable or faraway locations.
     Otherwise these tables would become annoyingly large.
+    For example, do not create a name <code>Indian/Crozet</code>
+    as a near-duplicate or alias of <code>Asia/Dubai</code>
+    merely because they are different countries or territories,
+    or their clocks disagreed before 1970, or the
+    <a href="https://en.wikipedia.org/wiki/Crozet_Islands">Crozet Islands</a>
+    are notable in their own right,
+    or the Crozet Islands are not adjacent to other locations
+    that use <code>Asia/Dubai</code>.
   </li>
   <li>
     If boundaries between regions are fluid, such as during a war or
@@ -579,10 +590,10 @@ in decreasing order of importance:
     locations while uninhabited.
     The leading '<code>-</code>' is a flag that the <abbr>UT</abbr> offset is in
     some sense undefined; this notation is derived
-    from <a href="https://datatracker.ietf.org/doc/html/rfc3339">Internet
+    from <a href="https://www.rfc-editor.org/rfc/rfc3339">Internet
     <abbr title="Request For Comments">RFC</abbr> 3339</a>.
     (The abbreviation 'Z' that
-    <a href="https://datatracker.ietf.org/doc/html/rfc9557">Internet
+    <a href="https://www.rfc-editor.org/rfc/rfc9557">Internet
     <abbr>RFC</abbr> 9557</a> uses for this concept
     would violate the POSIX requirement
     of at least three characters in an abbreviation.)
@@ -1115,8 +1126,8 @@ However POSIX.1-2024, like earlier POSIX editions, has some limitations:
     the name of a file from which time-related information is read.
     The file's format is <dfn><abbr>TZif</abbr></dfn>,
     a timezone information format that contains binary data; see
-    <a href="https://datatracker.ietf.org/doc/html/8536">Internet
+    <a href="https://www.rfc-editor.org/rfc/9636">Internet
-    <abbr>RFC</abbr> 8536</a>.
+    <abbr>RFC</abbr> 9636</a>.
     The daylight saving time rules to be used for a
     particular timezone are encoded in the
     <abbr>TZif</abbr> file; the format of the file allows <abbr>US</abbr>,
@@ -1201,12 +1212,15 @@ The vestigial <abbr>API</abbr>s are:
     The <code>tm_isdst</code> member is almost never needed and most of
     its uses should be discouraged in favor of the abovementioned
     <abbr>API</abbr>s.
+    It was intended as an index into the <code>tzname</code> variable,
+    but as mentioned previously that usage is obsolete.
     Although it can still be used in arguments to
     <code>mktime</code> to disambiguate timestamps near
     a <abbr>DST</abbr> transition when the clock jumps back on
     platforms lacking <code>tm_gmtoff</code>, this
-    disambiguation does not work when standard time itself jumps back,
+    disambiguation works only for proleptic <code>TZ</code> strings;
-    which can occur when a location changes to a time zone with a
+    it does not work in general for geographical timezones,
+    such as when a location changes to a time zone with a
     lesser <abbr>UT</abbr> offset.
   </li>
 </ul>
@@ -1223,8 +1237,8 @@ The vestigial <abbr>API</abbr>s are:
     Programs that in the past used the <code>timezone</code> function
     may now examine <code>localtime(&amp;clock)-&gt;tm_zone</code>
     (if <code>TM_ZONE</code> is defined) or
-    <code>tzname[localtime(&amp;clock)-&gt;tm_isdst]</code>
+    use <code>strftime</code> with a <code>%Z</code> conversion specification
-    (if <code>HAVE_TZNAME</code> is nonzero) to learn the correct time
+    to learn the correct time
     zone abbreviation to use.
   </li>
   <li>

contrib/tzcode/tz-link.html

@@ -194,9 +194,9 @@ After obtaining the code and data files, see the
 The code lets you compile the <code><abbr>tz</abbr></code> source files into
 machine-readable binary files, one for each location. The binary files
 are in a special format specified by
-<a href="https://datatracker.ietf.org/doc/html/8536">The
+<a href="https://www.rfc-editor.org/rfc/9636">The
 Time Zone Information Format (<abbr>TZif</abbr>)</a>
-(Internet <abbr title="Request For Comments">RFC</abbr> 8536).
+(Internet <abbr title="Request For Comments">RFC</abbr> 9636).
 The code also lets
 you read a <abbr>TZif</abbr> file and interpret timestamps for that
 location.</p>
@@ -260,7 +260,7 @@ Studio Code</a>.
 </p>
 <p>
 For further information about updates, please see
-<a href="https://datatracker.ietf.org/doc/html/rfc6557">Procedures for
+<a href="https://www.rfc-editor.org/rfc/rfc6557">Procedures for
 Maintaining the Time Zone Database</a> (Internet <abbr>RFC</abbr> 6557).
 More detail can be
 found in <a href="theory.html">Theory and pragmatics of the
@@ -379,26 +379,26 @@ calculates the current time difference between locations.</li>
 <li>The <a href="https://www.ietf.org">Internet Engineering Task Force</a>'s
 <a href="https://datatracker.ietf.org/wg/tzdist/charter/">Time Zone Data
 Distribution Service (tzdist) working group</a> defined <a
-href="https://datatracker.ietf.org/doc/html/rfc7808">TZDIST</a>
+href="https://www.rfc-editor.org/rfc/rfc7808">TZDIST</a>
 (Internet <abbr>RFC</abbr> 7808), a time zone data distribution service,
-along with <a href="https://datatracker.ietf.org/doc/html/rfc7809">CalDAV</a>
+along with <a href="https://www.rfc-editor.org/rfc/rfc7809">CalDAV</a>
 (Internet <abbr>RFC</abbr> 7809), a calendar access protocol for
 transferring time zone data by reference.
 <a href="https://devguide.calconnect.org/Time-Zones/TZDS/">TZDIST
 implementations</a> are available.
 The <a href="https://www.ietf.org/mailman/listinfo/tzdist-bis">tzdist-bis
 mailing list</a> discusses possible extensions.</li>
-<li>The <a href="https://datatracker.ietf.org/doc/html/rfc5545">
+<li>The <a href="https://www.rfc-editor.org/rfc/rfc5545">
 Internet Calendaring and Scheduling Core Object Specification
 (iCalendar)</a> (Internet <abbr>RFC</abbr> 5445)
 covers time zone
 data; see its VTIMEZONE calendar component.
 The iCalendar format requires specialized parsers and generators; a
-variant <a href="https://datatracker.ietf.org/doc/html/rfc6321">xCal</a>
+variant <a href="https://www.rfc-editor.org/rfc/rfc6321">xCal</a>
 (Internet <abbr>RFC</abbr> 6321) uses
 <a href="https://www.w3.org/XML/"><abbr
 title="Extensible Markup Language">XML</abbr></a> format, and a variant
-<a href="https://datatracker.ietf.org/doc/html/rfc7265">jCal</a>
+<a href="https://www.rfc-editor.org/rfc/rfc7265">jCal</a>
 (Internet <abbr>RFC</abbr> 7265)
 uses <a href="https://www.json.org/json-en.html"><abbr
 title="JavaScript Object Notation">JSON</abbr></a> format.</li>
@@ -935,7 +935,13 @@ with perhaps the best-documented history of clock adjustments.</dd>
 <dt>United States</dt>
 <dd>The Department of Transportation's <a
 href="https://www.transportation.gov/regulations/recent-time-zone-proceedings">Recent
-Time Zone Proceedings</a> lists changes to time zone boundaries.</dd>
+Time Zone Proceedings</a> lists changes to
+official written time zone boundaries, and its <a
+href="https://geodata.bts.gov/datasets/usdot::time-zones/about">Time
+Zones dataset</a> maps current boundaries.
+These boundaries are only for standard time, so the current map puts
+all of Arizona in one time zone even though part of Arizona
+observes <abbr>DST</abbr> and part does not.</dd>
 <dt>Uruguay</dt>
 <dd>The Oceanography, Hydrography, and Meteorology Service of the Uruguayan
 Navy (SOHMA) publishes an annual <a
@@ -979,6 +985,14 @@ a Sleep Research Society position statement</a>.
 doi:<a href="https://doi.org/10.1093/sleep/zsac236">10.1093/sleep/zsac236</a>.
 After reviewing the scientific literature, the Sleep Research Society
 advocates permanent standard time due to its health benefits.
+<li>Neumann P, von Blanckenburg K. <a
+href="https://journals.sagepub.com/doi/full/10.1177/0961463X241310562">What
+time will it be? A comprehensive literature review on daylight saving time</a>.
+<em>Time Soc</em>. 2025-01-21.
+doi:<a href="https://doi.org/10.1177/0961463X241310562">10.1177/0961463X241310562</a>.
+This reviews DST's effects on electricity, health, crime, road safety,
+and the economy, focusing on research since 2010, and concludes that
+year-round standard time is preferable overall.
 <li>Rishi MA, Cheng JY, Strang AR <em>et al</em>.
 <a href="https://jcsm.aasm.org/doi/10.5664/jcsm.10898">Permanent standard time
 is the optimal choice for health and safety:
@@ -994,7 +1008,8 @@ should we abolish Daylight Saving Time?</a>
 <em>J Biol Rhythms.</em> 2019;34(3):227&ndash;230.
 doi:<a href="https://doi.org/10.1177/0748730419854197">10.1177/0748730419854197</a>.
 The Society for Research on Biological Rhythms
-opposes DST changes and permanent DST, and advocates that governments adopt
+opposes <abbr>DST</abbr> changes and permanent <abbr>DST</abbr>,
+and advocates that governments adopt
 "permanent Standard Time for the health and safety of their citizens".</li>
 </ul>
 </section>
@@ -1023,7 +1038,7 @@ title="Institute of Electrical and Electronics Engineers">IEEE</abbr> 1588)
 can achieve submicrosecond clock accuracy on a local area network
 with special-purpose hardware.</li>
 <li><a
-href="https://datatracker.ietf.org/doc/html/rfc4833">Timezone
+href="https://www.rfc-editor.org/rfc/rfc4833">Timezone
 Options for <abbr title="Dynamic Host Configuration Protocol">DHCP</abbr></a>
 (Internet <abbr>RFC</abbr> 4833)
 specifies a <a
@@ -1105,7 +1120,7 @@ the abovementioned <abbr>NTP</abbr> implementations, <a
 href="https://github.com/google/unsmear">supports</a> conversion between
 <abbr>UTC</abbr> and smeared <abbr>POSIX</abbr> timestamps, and is used by major
 cloud service providers. However, according to
-<a href="https://datatracker.ietf.org/doc/html/rfc8633#section-3.7.1">&sect;3.7.1 of
+<a href="https://www.rfc-editor.org/rfc/rfc8633#section-3.7.1">&sect;3.7.1 of
 Network Time Protocol Best Current Practices</a>
 (Internet <abbr>RFC</abbr> 8633), leap smearing is not suitable for
 applications requiring accurate <abbr>UTC</abbr> or civil time,
@@ -1165,16 +1180,16 @@ interchange &ndash; Part 1: Basic rules</em></a>.</li>
 <a href="https://www.w3.org/TR/xmlschema/#dateTime"><abbr>XML</abbr>
 Schema: Datatypes &ndash; dateTime</a> specifies a format inspired by
 <abbr>ISO</abbr> 8601 that is in common use in <abbr>XML</abbr> data.</li>
-<li><a href="https://datatracker.ietf.org/doc/html/rfc5322#section-3.3">&sect;3.3 of
+<li><a href="https://www.rfc-editor.org/rfc/rfc5322#section-3.3">&sect;3.3 of
 Internet Message Format</a> (Internet <abbr>RFC</abbr> 5322)
 specifies the time notation used in email and <a
 href="https://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol"><abbr>HTTP</abbr></a>
 headers.</li>
 <li>
-<a href="https://datatracker.ietf.org/doc/html/rfc3339">Date and Time
+<a href="https://www.rfc-editor.org/rfc/rfc3339">Date and Time
 on the Internet: Timestamps</a> (Internet <abbr>RFC</abbr> 3339)
 specifies an <abbr>ISO</abbr> 8601 profile for use in new Internet protocols.
-An extension, <a href="https://datatracker.ietf.org/doc/html/rfc9557">Date
+An extension, <a href="https://www.rfc-editor.org/rfc/rfc9557">Date
 and Time on the Internet: Timestamps with Additional Information</a>
 (Internet <abbr>RFC</abbr> 9557) extends this profile
 to let you specify the <code><abbr>tzdb</abbr></code> timezone of a timestamp

contrib/tzcode/tzfile.5

@@ -11,7 +11,7 @@ The timezone information files used by
 .Xr tzset 3
 are found under
 .Pa /usr/share/zoneinfo .
-These files use the format described in Internet RFC 8536.
+These files use the format described in Internet RFC 9636.
 Each file is a sequence of 8-bit bytes.
 In a file, a binary integer is represented by a sequence of one or
 more bytes in network order (bigendian, or high-order byte first),
@@ -107,7 +107,7 @@ and
 serves as an index into the array of time zone abbreviation bytes
 that follow the
 .Vt ttinfo
-entries in the file; if the designated string is "\*-00", the
+entries in the file; if the designated string is "\-00", the
 .Vt ttinfo
 entry is a placeholder indicating that local time is unspecified.
 The
@@ -128,7 +128,7 @@ The byte strings can overlap if one is a suffix of the other.
 The encoding of these strings is not specified.
 .It Va tzh_leapcnt
 pairs of four-byte values, written in network byte order;
-the first value of each pair gives the nonnegative time
+the first value of each pair gives the non-negative time
 (as returned by
 .Xr time 3 )
 at which a leap second occurs or at which the leap second table expires;
@@ -141,7 +141,7 @@ Each pair denotes one leap second, either positive or negative,
 except that if the last pair has the same correction as the previous one,
 the last pair denotes the leap second table's expiration time.
 Each leap second is at the end of a UTC calendar month.
-The first leap second has a nonnegative occurrence time,
+The first leap second has a non-negative occurrence time,
 and is a positive leap second if and only if its correction is positive;
 the correction for each leap second after the first differs
 from the previous leap second by either 1 for a positive leap second,
@@ -168,7 +168,7 @@ The standard/wall and UT/local indicators were designed for
 transforming a TZif file's transition times into transitions appropriate
 for another time zone specified via
 a proleptic TZ string that lacks rules.
-For example, when TZ="EET\*-2EEST" and there is no TZif file "EET\*-2EEST",
+For example, when TZ="EET\-2EEST" and there is no TZif file "EET\-2EEST",
 the idea was to adapt the transition times from a TZif file with the
 well-known name "posixrules" that is present only for this purpose and
 is a copy of the file "Europe/Brussels", a file with a different UT offset.
@@ -177,7 +177,7 @@ the default rules are installation-dependent, and no implementation
 is known to support this feature for timestamps past 2037,
 so users desiring (say) Greek time should instead specify
 TZ="Europe/Athens" for better historical coverage, falling back on
-TZ="EET\*-2EEST,M3.5.0/3,M10.5.0/4" if POSIX conformance is required
+TZ="EET\-2EEST,M3.5.0/3,M10.5.0/4" if POSIX conformance is required
 and older timestamps need not be handled accurately.
 .Pp
 The
@@ -203,7 +203,7 @@ after the last transition time stored in the file
 or for all instants if the file has no transitions.
 The TZ string is empty (i.e., nothing between the newlines)
 if there is no proleptic representation for such instants.
-If nonempty, the TZ string must agree with the local time
+If non-empty, the TZ string must agree with the local time
 type after the last transition time if present in the eight-byte data;
 for example, given the string
 .Dq "WET0WEST,M3.5.0/1,M10.5.0"
@@ -218,7 +218,7 @@ the earliest transition time.
 For version-3-format timezone files, a TZ string (see
 .Xr newtzset 3 )
 may use the following POSIX.1-2024 extensions to POSIX.1-2017:
-First, as in TZ="<\*-02>2<\*-01>,M3.5.0/\*-1,M10.5.0/0",
+First, as in TZ="<\-02>2<\-01>,M3.5.0/\-1,M10.5.0/0",
 the hours part of its transition times may be signed and range from
 \-167 through 167 instead of being limited to unsigned values
 from 0 through 24.
@@ -275,7 +275,7 @@ time did not exist (possibly with an error indication).
 Time zone designations should consist of at least three (3)
 and no more than six (6) ASCII characters from the set of
 alphanumerics,
-.Dq "\*-" ,
+.Dq "\-" ,
 and
 .Dq "+" .
 This is for compatibility with POSIX requirements for
@@ -300,16 +300,16 @@ through 60 instead of the usual 59; the UTC offset is unaffected.
 This section documents common problems in reading or writing TZif files.
 Most of these are problems in generating TZif files for use by
 older readers.
-The goals of this section are:
+The goals of this section are to help:
 .Bl -bullet
 .It
-to help TZif writers output files that avoid common
+TZif writers output files that avoid common
 pitfalls in older or buggy TZif readers,
 .It
-to help TZif readers avoid common pitfalls when reading
+TZif readers avoid common pitfalls when reading
 files generated by future TZif writers, and
 .It
-to help any future specification authors see what sort of
+any future specification authors see what sort of
 problems arise when the TZif format is changed.
 .El
 .Pp
@@ -320,9 +320,9 @@ reader was designed for.
 When complete compatibility was not achieved, an attempt was
 made to limit glitches to rarely used timestamps and allow
 simple partial workarounds in writers designed to generate
-new-version data useful even for older-version readers.
+newer-version data useful even for older-version readers.
 This section attempts to document these compatibility issues and
-workarounds, as well as to document other common bugs in
+workarounds as well as documenting other common bugs in
 readers.
 .Pp
 Interoperability problems with TZif include the following:
@@ -355,15 +355,15 @@ for two time zones east, e.g.,
 for a time zone with a never-used standard time (XXX, \-03)
 and negative daylight saving time (EDT, \-04) all year.
 Alternatively,
-as a partial workaround a writer can substitute standard time
+as a partial workaround, a writer can substitute standard time
 for the next time zone east \(en e.g.,
 .Dq "AST4"
 for permanent
 Atlantic Standard Time (\-04).
 .It
-Some readers designed for version 2 or 3, and that require strict
+Some readers designed for version 2 or 3 and that require strict
-conformance to RFC 8536, reject version 4 files whose leap second
+conformance to RFC 9636 reject version 4 files whose leap second
-tables are truncated at the start or that end in expiration times.
+tables are truncated at the start or end in expiration times.
 .It
 Some readers ignore the footer, and instead predict future
 timestamps from the time type of the last transition.
@@ -378,7 +378,7 @@ and even for current timestamps it can fail for settings like
 TZ="Africa/Casablanca".  This corresponds to a TZif file
 containing explicit transitions through the year 2087,
 followed by a footer containing the TZ string
-.Dq <+01>\*-1 ,
+.Dq <+01>\-1 ,
 which should be used only for timestamps after the last
 explicit transition.
 .It
@@ -389,7 +389,7 @@ As a partial workaround, a writer can output a dummy (no-op)
 first transition at an early time.
 .It
 Some readers mishandle timestamps before the first
-transition that has a timestamp not less than \-2**31.
+transition that has a timestamp that is not less than \-2**31.
 Readers that support only 32-bit timestamps are likely to be
 more prone to this problem, for example, when they process
 64-bit transitions only some of which are representable in 32
@@ -401,7 +401,7 @@ Some readers mishandle a transition if its timestamp has
 the minimum possible signed 64-bit value.
 Timestamps less than \-2**59 are not recommended.
 .It
-Some readers mishandle TZ strings that
+Some readers mishandle proleptic TZ strings that
 contain
 .Dq "<"
 or
@@ -418,9 +418,9 @@ non-ASCII characters.
 These characters are not recommended.
 .It
 Some readers may mishandle time zone abbreviations that
-contain fewer than 3 or more than 6 characters, or that
+contain fewer than 3 or more than 6 characters or that
 contain ASCII characters other than alphanumerics,
-.Dq "\*-",
+.Dq "\-",
 and
 .Dq "+".
 These abbreviations are not recommended.
@@ -430,7 +430,7 @@ daylight-saving time UT offsets that are less than the UT
 offsets for the corresponding standard time.
 These readers do not support locations like Ireland, which
 uses the equivalent of the TZ string
-.Dq "IST\*-1GMT0,M10.5.0,M3.5.0/1",
+.Dq "IST\-1GMT0,M10.5.0,M3.5.0/1",
 observing standard time
 (IST, +01) in summer and daylight saving time (GMT, +00) in winter.
 As a partial workaround, a writer can output data for the
@@ -443,7 +443,7 @@ abbreviations correctly.
 .It
 Some readers generate ambiguous timestamps for positive leap seconds
 that occur when the UTC offset is not a multiple of 60 seconds.
-For example, in a timezone with UTC offset +01:23:45 and with
+For example, with UTC offset +01:23:45 and
 a positive leap second 78796801 (1972-06-30 23:59:60 UTC), some readers will
 map both 78796800 and 78796801 to 01:23:45 local time the next day
 instead of mapping the latter to 01:23:46, and they will map 78796815 to
@@ -462,15 +462,15 @@ Developers of distributed applications should keep this
 in mind if they need to deal with pre-1970 data.
 .It
 Some readers mishandle timestamps before the first
-transition that has a nonnegative timestamp.
+transition that has a non-negative timestamp.
 Readers that do not support negative timestamps are likely to
 be more prone to this problem.
 .It
 Some readers mishandle time zone abbreviations like
-.Dq "\*-08"
+.Dq "\-08"
 that contain
-.Dq "+" ,
+.Dq "+",
-.Dq "\*-" ,
+.Dq "\-",
 or digits.
 .It
 Some readers mishandle UT offsets that are out of the
@@ -479,7 +479,7 @@ support locations like Kiritimati that are outside this
 range.
 .It
 Some readers mishandle UT offsets in the range [\-3599, \-1]
-seconds from UT, because they integer-divide the offset by
+seconds from UT because they integer-divide the offset by
 3600 to get 0 and then display the hour part as
 .Dq "+00" .
 .It
@@ -498,8 +498,8 @@ of one hour, or of 15 minutes, or of 1 minute.
 .%A P. Eggert
 .%A K. Murchison
 .%T "The Time Zone Information Format (TZif)"
-.%R RFC 8536
+.%R RFC 9636
-.%D February 2019
+.%D October 2024
-.%U https://datatracker.ietf.org/doc/html/rfc8536
+.%U https://datatracker.ietf.org/doc/html/rfc9636
-.%U https://doi.org/10.17487/RFC8536
+.%U https://doi.org/10.17487/RFC9636
 .Re

contrib/tzcode/tzfile.h

@@ -28,7 +28,7 @@
 #endif /* !defined TZDEFRULES */
 
 
-/* See Internet RFC 8536 for more details about the following format.  */
+/* See Internet RFC 9636 for more details about the following format.  */
 
 /*
 ** Each file begins with. . .

contrib/tzcode/tzselect.8

@@ -4,8 +4,6 @@
 .SH NAME
 tzselect \- select a timezone
 .SH SYNOPSIS
-.ie \n(.g .ds - \f(CR-\fP
-.el .ds - \-
 .ds d " degrees
 .ds m " minutes
 .ds s " seconds
@@ -20,15 +18,15 @@ tzselect \- select a timezone
 .\}
 .B tzselect
 [
-.B \*-c
+.B \-c
 .I coord
 ] [
-.B \*-n
+.B \-n
 .I limit
 ] [
-.B \*-\*-help
+.B \-\-help
 ] [
-.B \*-\*-version
+.B \-\-version
 ]
 .SH DESCRIPTION
 The
@@ -40,7 +38,7 @@ The output is suitable as a value for the TZ environment variable.
 All interaction with the user is done via standard input and standard error.
 .SH OPTIONS
 .TP
-.BI "\*-c " coord
+.BI "\-c " coord
 Instead of asking for continent and then country and then city,
 ask for selection from time zones whose largest cities
 are closest to the location with geographical coordinates
@@ -70,27 +68,27 @@ seconds, with any trailing fractions represent fractional minutes or
 .I SS
 is present) seconds.  The decimal point is that of the current locale.
 For example, in the (default) C locale,
-.B "\*-c\ +40.689\*-074.045"
+.B "\-c\ +40.689\-074.045"
 specifies 40.689\*d\*_N, 74.045\*d\*_W,
-.B "\*-c\ +4041.4\*-07402.7"
+.B "\-c\ +4041.4\-07402.7"
 specifies 40\*d\*_41.4\*m\*_N, 74\*d\*_2.7\*m\*_W, and
-.B "\*-c\ +404121\*-0740240"
+.B "\-c\ +404121\-0740240"
 specifies 40\*d\*_41\*m\*_21\*s\*_N, 74\*d\*_2\*m\*_40\*s\*_W.
 If
 .I coord
 is not one of the documented forms, the resulting behavior is unspecified.
 .TP
-.BI "\*-n " limit
+.BI "\-n " limit
 When
-.B \*-c
+.B \-c
 is used, display the closest
 .I limit
 locations (default 10).
 .TP
-.B "\*-\*-help"
+.B "\-\-help"
 Output help information and exit.
 .TP
-.B "\*-\*-version"
+.B "\-\-version"
 Output version information and exit.
 .SH "ENVIRONMENT VARIABLES"
 .TP

contrib/tzcode/version

@@ -1 +1 @@
-2024b
+2025b

contrib/tzcode/zdump.8

@@ -28,6 +28,14 @@ The
 program prints the current time in each
 .Ar timezone
 named on the command line.
+A
+.Ar timezone
+of
+.Li -
+is treated as if it were
+.Pa /dev/stdin ;
+this can be used to pipe TZif data into
+.Nm .
 .Pp
 The following options are available:
 .Bl -tag -width indent
@@ -106,7 +114,7 @@ then a line
 where
 .Ar string
 is a double-quoted string giving the timezone, a second line
-.Dq "\*- \*- \fIinterval\fP"
+.Dq "\- \- \fIinterval\fP"
 describing the time interval before the first transition if any, and
 zero or more following lines
 .Dq "\fIdate time interval\fP",
@@ -138,11 +146,11 @@ the seconds are omitted if they are zero, and
 the minutes are also omitted if they are also zero.
 Positive UT
 offsets are east of Greenwich.
-The UT offset \*-00 denotes a UT
+The UT offset \-00 denotes a UT
 placeholder in areas where the actual offset is unspecified; by
 convention, this occurs when the UT offset is zero and the time zone
 abbreviation begins with
-.Dq "-"
+.Dq "\-"
 or is
 .Dq "zzz".
 .Pp

contrib/tzcode/zdump.c

@@ -14,10 +14,6 @@
 #include "private.h"
 #include <stdio.h>
 
-#ifndef HAVE_SNPRINTF
-# define HAVE_SNPRINTF (!PORT_TO_C89 || 199901 <= __STDC_VERSION__)
-#endif
-
 #ifndef HAVE_LOCALTIME_R
 # define HAVE_LOCALTIME_R 1
 #endif
@@ -148,17 +144,6 @@ sumsize(ptrdiff_t a, ptrdiff_t b)
   size_overflow();
 }
 
-/* Return the size of of the string STR, including its trailing NUL.
-   Report an error and exit if this would exceed INDEX_MAX which means
-   pointer subtraction wouldn't work.  */
-static ptrdiff_t
-xstrsize(char const *str)
-{
-  size_t len = strlen(str);
-  if (len < INDEX_MAX)
-    return len + 1;
-  size_overflow();
-}
 
 /* Return a pointer to a newly allocated buffer of size SIZE, exiting
    on failure.  SIZE should be positive.  */
@@ -266,7 +251,7 @@ tzalloc(char const *val)
   static ptrdiff_t fakeenv0size;
   void *freeable = NULL;
   char **env = fakeenv, **initial_environ;
-  ptrdiff_t valsize = xstrsize(val);
+  ptrdiff_t valsize = strlen(val) + 1;
   if (fakeenv0size < valsize) {
     char **e = environ, **to;
     ptrdiff_t initial_nenvptrs = 1;  /* Counting the trailing NULL pointer.  */
@@ -427,7 +412,7 @@ saveabbr(char **buf, ptrdiff_t *bufalloc, struct tm const *tmp)
   if (HAVE_LOCALTIME_RZ)
     return ab;
   else {
-    ptrdiff_t absize = xstrsize(ab);
+    ptrdiff_t absize = strlen(ab) + 1;
     if (*bufalloc < absize) {
       free(*buf);
 
@@ -489,6 +474,7 @@ main(int argc, char *argv[])
 	register time_t		cuthitime;
 	time_t			now;
 	bool iflag = false;
+	size_t arglenmax = 0;
 
 	cutlotime = absolute_min_time;
 	cuthitime = absolute_max_time;
@@ -588,15 +574,21 @@ main(int argc, char *argv[])
 	  now = time(NULL);
 	  now |= !now;
 	}
-	longest = 0;
 	for (i = optind; i < argc; i++) {
 	  size_t arglen = strlen(argv[i]);
-	  if (longest < arglen)
+	  if (arglenmax < arglen)
-	    longest = min(arglen, INT_MAX);
+	    arglenmax = arglen;
 	}
+	if (!HAVE_SETENV && INDEX_MAX <= arglenmax)
+	  size_overflow();
+	longest = min(arglenmax, INT_MAX - 2);
 
 	for (i = optind; i < argc; ++i) {
-		timezone_t tz = tzalloc(argv[i]);
+		/* Treat "-" as standard input on platforms with /dev/stdin.
+		   It's not worth the bother of supporting "-" on other
+		   platforms, as that would need temp files.  */
+		timezone_t tz = tzalloc(strcmp(argv[i], "-") == 0
+					? "/dev/stdin" : argv[i]);
 		char const *ab;
 		time_t t;
 		struct tm tm, newtm;
@@ -697,7 +689,7 @@ yeartot(intmax_t y)
 				return absolute_max_time;
 			seconds = diff400 * SECSPER400YEARS;
 			years = diff400 * 400;
-                } else {
+		} else {
 			seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
 			years = 1;
 		}
@@ -928,13 +920,10 @@ showextrema(timezone_t tz, char *zone, time_t lo, struct tm *lotmp, time_t hi)
   }
 }
 
-#if HAVE_SNPRINTF
+/* On pre-C99 platforms, a snprintf substitute good enough for us.  */
-# define my_snprintf snprintf
+#if !HAVE_SNPRINTF
-#else
 # include <stdarg.h>
-
+ATTRIBUTE_FORMAT((printf, 3, 4)) static int
-/* A substitute for snprintf that is good enough for zdump.  */
-static int
 my_snprintf(char *s, size_t size, char const *format, ...)
 {
   int n;
@@ -962,6 +951,7 @@ my_snprintf(char *s, size_t size, char const *format, ...)
   va_end(args);
   return n;
 }
+# define snprintf my_snprintf
 #endif
 
 /* Store into BUF, of size SIZE, a formatted local time taken from *TM.
@@ -976,10 +966,10 @@ format_local_time(char *buf, ptrdiff_t size, struct tm const *tm)
 {
   int ss = tm->tm_sec, mm = tm->tm_min, hh = tm->tm_hour;
   return (ss
-	  ? my_snprintf(buf, size, "%02d:%02d:%02d", hh, mm, ss)
+	  ? snprintf(buf, size, "%02d:%02d:%02d", hh, mm, ss)
 	  : mm
-	  ? my_snprintf(buf, size, "%02d:%02d", hh, mm)
+	  ? snprintf(buf, size, "%02d:%02d", hh, mm)
-	  : my_snprintf(buf, size, "%02d", hh));
+	  : snprintf(buf, size, "%02d", hh));
 }
 
 /* Store into BUF, of size SIZE, a formatted UT offset for the
@@ -1014,10 +1004,10 @@ format_utc_offset(char *buf, ptrdiff_t size, struct tm const *tm, time_t t)
   mm = off / 60 % 60;
   hh = off / 60 / 60;
   return (ss || 100 <= hh
-	  ? my_snprintf(buf, size, "%c%02ld%02d%02d", sign, hh, mm, ss)
+	  ? snprintf(buf, size, "%c%02ld%02d%02d", sign, hh, mm, ss)
 	  : mm
-	  ? my_snprintf(buf, size, "%c%02ld%02d", sign, hh, mm)
+	  ? snprintf(buf, size, "%c%02ld%02d", sign, hh, mm)
-	  : my_snprintf(buf, size, "%c%02ld", sign, hh));
+	  : snprintf(buf, size, "%c%02ld", sign, hh));
 }
 
 /* Store into BUF (of size SIZE) a quoted string representation of P.
@@ -1120,7 +1110,7 @@ istrftime(char *buf, ptrdiff_t size, char const *time_fmt,
 	    for (abp = ab; is_alpha(*abp); abp++)
 	      continue;
 	    len = (!*abp && *ab
-		   ? my_snprintf(b, s, "%s", ab)
+		   ? snprintf(b, s, "%s", ab)
 		   : format_quoted_string(b, s, ab));
 	    if (s <= len)
 	      return false;
@@ -1128,7 +1118,7 @@ istrftime(char *buf, ptrdiff_t size, char const *time_fmt,
 	  }
 	  formatted_len
 	    = (tm->tm_isdst
-	       ? my_snprintf(b, s, &"\t\t%d"[show_abbr], tm->tm_isdst)
+	       ? snprintf(b, s, &"\t\t%d"[show_abbr], tm->tm_isdst)
 	       : 0);
 	}
 	break;

contrib/tzcode/zic.8

@@ -112,13 +112,13 @@ Link	\fItimezone\fP		posixrules
 If
 .Ar timezone
 is
-.Dq "\*-"
+.Dq "\-"
 (the default), any already-existing link is removed.
 .Pp
 Unless
 .Ar timezone
 is
-.Dq "\*-" ,
+.Dq "\-" ,
 this option is obsolete and poorly supported.
 Among other things it should not be used for timestamps after the year 2037,
 and it should not be combined with
@@ -148,6 +148,10 @@ omits data intended for negative timestamps (i.e., before the Epoch), and
 .Fl r @0/@2147483648
 outputs data intended only for nonnegative timestamps that fit into
 31-bit signed integers.
+On platforms with GNU
+.Nm date ,
+.Dq "zic \-r @$(date +%s)"
+omits data intended for past timestamps.
 Although this option typically reduces the output file's size,
 the size can increase due to the need to represent the timestamp range
 boundaries, particularly if
@@ -366,7 +370,15 @@ separate script to further restrict in which
 of years the rule would apply.
 .It IN
 Names the month in which the rule takes effect.
-Month names may be abbreviated.
+Month names may be abbreviated as mentioned previously;
+for example, January can appear as
+.Dq January ,
+.Dq JANU
+or
+.Dq Ja ,
+but not as
+.Dq j
+which would be ambiguous with both June and July.
 .It ON
 Gives the day on which the rule takes effect.
 Recognized forms include:
@@ -389,7 +401,12 @@ or a weekday name preceded by
 .Dq "last"
 (e.g.,
 .Ql "lastSunday" )
-may be abbreviated or spelled out in full.
+may be abbreviated as mentioned previously,
+e.g.,
+.Dq Su
+for Sunday and
+.Dq lastsa
+for the last Saturday.
 There must be no white space characters within the
 .Ar ON
 field.
@@ -540,7 +557,7 @@ field,
 giving the amount of time to be added to local standard time
 and whether the resulting time is standard or daylight saving.
 Standard time applies if this field is
-.Ql \*-
+.Ql \-
 or for timestamps occurring before any rule takes effect.
 When an amount of time is given, only the sum of standard time and
 this amount matters.

contrib/tzcode/zic.c

@@ -526,19 +526,19 @@ memcheck(void *ptr)
 }
 
 static void *
-emalloc(size_t size)
+xmalloc(size_t size)
 {
   return memcheck(malloc(size));
 }
 
 static void *
-erealloc(void *ptr, size_t size)
+xrealloc(void *ptr, size_t size)
 {
   return memcheck(realloc(ptr, size));
 }
 
 static char *
-estrdup(char const *str)
+xstrdup(char const *str)
 {
   return memcheck(strdup(str));
 }
@@ -567,7 +567,7 @@ growalloc(void *ptr, ptrdiff_t itemsize, ptrdiff_t nitems,
 {
   return (nitems < *nitems_alloc
 	  ? ptr
-	  : erealloc(ptr, grow_nitems_alloc(nitems_alloc, itemsize)));
+	  : xrealloc(ptr, grow_nitems_alloc(nitems_alloc, itemsize)));
 }
 
 /*
@@ -654,6 +654,8 @@ close_file(FILE *stream, char const *dir, char const *name,
   char const *e = (ferror(stream) ? _("I/O error")
 		   : fclose(stream) != 0 ? strerror(errno) : NULL);
   if (e) {
+    if (name && *name == '/')
+      dir = NULL;
     fprintf(stderr, "%s: %s%s%s%s%s\n", progname,
 	    dir ? dir : "", dir ? "/" : "",
 	    name ? name : "", name ? ": " : "",
@@ -961,6 +963,9 @@ static mode_t		mflag = (S_IRUSR | S_IRGRP | S_IROTH
 				 | S_IWUSR);
 static const char *	tzdefault;
 
+/* True if DIRECTORY ends in '/'.  */
+static bool directory_ends_in_slash;
+
 /* -1 if the TZif output file should be slim, 0 if default, 1 if the
    output should be fat for backward compatibility.  ZIC_BLOAT_DEFAULT
    determines the default.  */
@@ -1166,6 +1171,7 @@ _("invalid file mode"));
 		return EXIT_FAILURE;
 	associate();
 	change_directory(directory);
+	directory_ends_in_slash = directory[strlen(directory) - 1] == '/';
 	catch_signals();
 	for (i = 0; i < nzones; i = j) {
 		/*
@@ -1353,7 +1359,7 @@ random_dirent(char const **name, char **namealloc)
   uint_fast64_t unfair_min = - ((UINTMAX_MAX % base__6 + 1) % base__6);
 
   if (!dst) {
-    dst = emalloc(size_sum(dirlen, prefixlen + suffixlen + 1));
+    dst = xmalloc(size_sum(dirlen, prefixlen + suffixlen + 1));
     memcpy(dst, src, dirlen);
     memcpy(dst + dirlen, prefix, prefixlen);
     dst[dirlen + prefixlen + suffixlen] = '\0';
@@ -1370,6 +1376,20 @@ random_dirent(char const **name, char **namealloc)
   }
 }
 
+/* For diagnostics the directory, and file name relative to that
+   directory, respectively.  A diagnostic routine can name FILENAME by
+   outputting diagdir(FILENAME), then diagslash(FILENAME), then FILENAME.  */
+static char const *
+diagdir(char const *filename)
+{
+  return *filename == '/' ? "" : directory;
+}
+static char const *
+diagslash(char const *filename)
+{
+  return &"/"[*filename == '/' || directory_ends_in_slash];
+}
+
 /* Prepare to write to the file *OUTNAME, using *TEMPNAME to store the
    name of the temporary file that will eventually be renamed to
    *OUTNAME.  Assign the temporary file's name to both *OUTNAME and
@@ -1406,8 +1426,9 @@ open_outfile(char const **outname, char **tempname)
     } else if (fopen_errno == EEXIST)
       random_dirent(outname, tempname);
     else {
-      fprintf(stderr, _("%s: Can't create %s/%s: %s\n"),
+      fprintf(stderr, _("%s: Can't create %s%s%s: %s\n"),
-	      progname, directory, *outname, strerror(fopen_errno));
+	      progname, diagdir(*outname), diagslash(*outname), *outname,
+	      strerror(fopen_errno));
       exit(EXIT_FAILURE);
     }
   }
@@ -1424,9 +1445,10 @@ rename_dest(char *tempname, char const *name)
   if (tempname) {
     if (rename(tempname, name) != 0) {
       int rename_errno = errno;
-      (void)remove(tempname);
+      remove(tempname);
-      fprintf(stderr, _("%s: rename to %s/%s: %s\n"),
+      fprintf(stderr, _("%s: rename to %s%s%s: %s\n"),
-	      progname, directory, name, strerror(rename_errno));
+	      progname, diagdir(name), diagslash(name), name,
+	      strerror(rename_errno));
       exit(EXIT_FAILURE);
     }
     free(tempname);
@@ -1436,7 +1458,8 @@ rename_dest(char *tempname, char const *name)
 /* Create symlink contents suitable for symlinking TARGET to LINKNAME, as a
    freshly allocated string.  TARGET should be a relative file name, and
    is relative to the global variable DIRECTORY.  LINKNAME can be either
-   relative or absolute.  */
+   relative or absolute.  Return a null pointer if the symlink contents
+   was not computed because LINKNAME is absolute but DIRECTORY is not.  */
 static char *
 relname(char const *target, char const *linkname)
 {
@@ -1449,8 +1472,10 @@ relname(char const *target, char const *linkname)
     size_t len = strlen(directory);
     size_t lenslash = len + (len && directory[len - 1] != '/');
     size_t targetsize = strlen(target) + 1;
+    if (*directory != '/')
+      return NULL;
     linksize = size_sum(lenslash, targetsize);
-    f = result = emalloc(linksize);
+    f = result = xmalloc(linksize);
     memcpy(result, directory, len);
     result[len] = '/';
     memcpy(result + lenslash, target, targetsize);
@@ -1464,7 +1489,7 @@ relname(char const *target, char const *linkname)
   dotdotetcsize = size_sum(size_product(dotdots, 3), taillen + 1);
   if (dotdotetcsize <= linksize) {
     if (!result)
-      result = emalloc(dotdotetcsize);
+      result = xmalloc(dotdotetcsize);
     for (i = 0; i < dotdots; i++)
       memcpy(result + 3 * i, "../", 3);
     memmove(result + 3 * dotdots, f + dir_len, taillen + 1);
@@ -1500,8 +1525,9 @@ dolink(char const *target, char const *linkname, bool staysymlink)
 	    return;
 	  else {
 	    char const *e = strerror(errno);
-	    fprintf(stderr, _("%s: Can't remove %s/%s: %s\n"),
+	    fprintf(stderr, _("%s: Can't remove %s%s%s: %s\n"),
-		    progname, directory, linkname, e);
+		    progname, diagdir(linkname), diagslash(linkname), linkname,
+		    e);
 	    exit(EXIT_FAILURE);
 	  }
 	}
@@ -1544,8 +1570,9 @@ dolink(char const *target, char const *linkname, bool staysymlink)
 	    mkdirs(linkname, true);
 	    linkdirs_made = true;
 	  } else {
-	    fprintf(stderr, _("%s: Can't link %s/%s to %s/%s: %s\n"),
+	    fprintf(stderr, _("%s: Can't link %s%s%s to %s%s%s: %s\n"),
-		    progname, directory, target, directory, outname,
+		    progname, diagdir(target), diagslash(target), target,
+		    diagdir(outname), diagslash(outname), outname,
 		    strerror(link_errno));
 	    exit(EXIT_FAILURE);
 	  }
@@ -1554,21 +1581,23 @@ dolink(char const *target, char const *linkname, bool staysymlink)
 	  bool absolute = *target == '/';
 	  char *linkalloc = absolute ? NULL : relname(target, linkname);
 	  char const *contents = absolute ? target : linkalloc;
-	  int symlink_errno;
+	  int symlink_errno = -1;
 
-	  while (true) {
+	  if (contents) {
-	    if (symlink(contents, outname) == 0) {
+	    while (true) {
-	      symlink_errno = 0;
+	      if (symlink(contents, outname) == 0) {
-	      break;
+		symlink_errno = 0;
+		break;
+	      }
+	      symlink_errno = errno;
+	      if (symlink_errno == EEXIST)
+		random_dirent(&outname, &tempname);
+	      else if (symlink_errno == ENOENT && !linkdirs_made) {
+		mkdirs(linkname, true);
+		linkdirs_made = true;
+	      } else
+		break;
 	    }
-	    symlink_errno = errno;
-	    if (symlink_errno == EEXIST)
-	      random_dirent(&outname, &tempname);
-	    else if (symlink_errno == ENOENT && !linkdirs_made) {
-	      mkdirs(linkname, true);
-	      linkdirs_made = true;
-	    } else
-	      break;
 	  }
 	  free(linkalloc);
 	  if (symlink_errno == 0) {
@@ -1581,8 +1610,8 @@ dolink(char const *target, char const *linkname, bool staysymlink)
 	    fp = fopen(target, "rb");
 	    if (!fp) {
 	      char const *e = strerror(errno);
-	      fprintf(stderr, _("%s: Can't read %s/%s: %s\n"),
+	      fprintf(stderr, _("%s: Can't read %s%s%s: %s\n"),
-		      progname, directory, target, e);
+		      progname, diagdir(target), diagslash(target), target, e);
 	      exit(EXIT_FAILURE);
 	    }
 	    tp = open_outfile(&outname, &tempname);
@@ -1593,6 +1622,8 @@ dolink(char const *target, char const *linkname, bool staysymlink)
 	    if (link_errno != ENOTSUP)
 	      warning(_("copy used because hard link failed: %s"),
 		      strerror(link_errno));
+	    else if (symlink_errno < 0)
+	      warning(_("copy used because symbolic link not obvious"));
 	    else if (symlink_errno != ENOTSUP)
 	      warning(_("copy used because symbolic link failed: %s"),
 		      strerror(symlink_errno));
@@ -1906,8 +1937,8 @@ inrule(char **fields, int nfields)
 		     fields[RF_COMMAND], fields[RF_MONTH], fields[RF_DAY],
 		     fields[RF_TOD]))
 	  return;
-	r.r_name = estrdup(fields[RF_NAME]);
+	r.r_name = xstrdup(fields[RF_NAME]);
-	r.r_abbrvar = estrdup(fields[RF_ABBRVAR]);
+	r.r_abbrvar = xstrdup(fields[RF_ABBRVAR]);
 	if (max_abbrvar_len < strlen(r.r_abbrvar))
 		max_abbrvar_len = strlen(r.r_abbrvar);
 	rules = growalloc(rules, sizeof *rules, nrules, &nrules_alloc);
@@ -1990,7 +2021,8 @@ inzsub(char **fields, int nfields, bool iscont)
 	z.z_filenum = filenum;
 	z.z_linenum = linenum;
 	z.z_stdoff = gethms(fields[i_stdoff], _("invalid UT offset"));
-	if ((cp = strchr(fields[i_format], '%')) != 0) {
+	cp = strchr(fields[i_format], '%');
+	if (cp) {
 		if ((*++cp != 's' && *cp != 'z') || strchr(cp, '%')
 		    || strchr(fields[i_format], '/')) {
 			error(_("invalid abbreviation format"));
@@ -2028,9 +2060,9 @@ inzsub(char **fields, int nfields, bool iscont)
 		  return false;
 		}
 	}
-	z.z_name = iscont ? NULL : estrdup(fields[ZF_NAME]);
+	z.z_name = iscont ? NULL : xstrdup(fields[ZF_NAME]);
-	z.z_rule = estrdup(fields[i_rule]);
+	z.z_rule = xstrdup(fields[i_rule]);
-	z.z_format = cp1 = estrdup(fields[i_format]);
+	z.z_format = cp1 = xstrdup(fields[i_format]);
 	if (z.z_format_specifier == 'z') {
 	  cp1[cp - fields[i_format]] = 's';
 	  if (noise)
@@ -2173,8 +2205,8 @@ inlink(char **fields, int nfields)
 	  return;
 	l.l_filenum = filenum;
 	l.l_linenum = linenum;
-	l.l_target = estrdup(fields[LF_TARGET]);
+	l.l_target = xstrdup(fields[LF_TARGET]);
-	l.l_linkname = estrdup(fields[LF_LINKNAME]);
+	l.l_linkname = xstrdup(fields[LF_LINKNAME]);
 	links = growalloc(links, sizeof *links, nlinks, &nlinks_alloc);
 	links[nlinks++] = l;
 }
@@ -2197,7 +2229,7 @@ rulesub(struct rule *rp, const char *loyearp, const char *hiyearp,
 	rp->r_month = lp->l_value;
 	rp->r_todisstd = false;
 	rp->r_todisut = false;
-	dp = estrdup(timep);
+	dp = xstrdup(timep);
 	if (*dp != '\0') {
 		ep = dp + strlen(dp) - 1;
 		switch (lowerit(*ep)) {
@@ -2272,19 +2304,23 @@ rulesub(struct rule *rp, const char *loyearp, const char *hiyearp,
 	**	Sun<=20
 	**	Sun>=7
 	*/
-	dp = estrdup(dayp);
+	dp = xstrdup(dayp);
 	if ((lp = byword(dp, lasts)) != NULL) {
 		rp->r_dycode = DC_DOWLEQ;
 		rp->r_wday = lp->l_value;
 		rp->r_dayofmonth = len_months[1][rp->r_month];
 	} else {
-		if ((ep = strchr(dp, '<')) != 0)
+		ep = strchr(dp, '<');
-			rp->r_dycode = DC_DOWLEQ;
+		if (ep)
-		else if ((ep = strchr(dp, '>')) != 0)
+		    rp->r_dycode = DC_DOWLEQ;
-			rp->r_dycode = DC_DOWGEQ;
 		else {
+		    ep = strchr(dp, '>');
+		    if (ep)
+			rp->r_dycode = DC_DOWGEQ;
+		    else {
 			ep = dp;
 			rp->r_dycode = DC_DOM;
+		    }
 		}
 		if (rp->r_dycode != DC_DOM) {
 			*ep++ = 0;
@@ -2427,7 +2463,7 @@ writezone(const char *const name, const char *const string, char version,
 	/* Allocate the ATS and TYPES arrays via a single malloc,
 	   as this is a bit faster.  Do not malloc(0) if !timecnt,
 	   as that might return NULL even on success.  */
-	zic_t *ats = emalloc(align_to(size_product(timecnt + !timecnt,
+	zic_t *ats = xmalloc(align_to(size_product(timecnt + !timecnt,
 						   sizeof *ats + 1),
 				      alignof(zic_t)));
 	void *typesptr = ats + timecnt;
@@ -2802,7 +2838,7 @@ writezone(const char *const name, const char *const string, char version,
 		if (thisleapexpiry) {
 		  /* Append a no-op leap correction indicating when the leap
 		     second table expires.  Although this does not conform to
-		     Internet RFC 8536, most clients seem to accept this and
+		     Internet RFC 9636, most clients seem to accept this and
 		     the plan is to amend the RFC to allow this in version 4
 		     TZif files.  */
 		  puttzcodepass(leapexpires, fp, pass);
@@ -3059,7 +3095,7 @@ stringzone(char *result, struct zone const *zpfirst, ptrdiff_t zonecount)
 
 	result[0] = '\0';
 
-	/* Internet RFC 8536 section 5.1 says to use an empty TZ string if
+	/* Internet RFC 9636 section 6.1 says to use an empty TZ string if
 	   future timestamps are truncated.  */
 	if (hi_time < max_time)
 	  return -1;
@@ -3187,9 +3223,9 @@ outzone(const struct zone *zpfirst, ptrdiff_t zonecount)
 	max_abbr_len = 2 + max_format_len + max_abbrvar_len;
 	max_envvar_len = 2 * max_abbr_len + 5 * 9;
 
-	startbuf = emalloc(max_abbr_len + 1);
+	startbuf = xmalloc(max_abbr_len + 1);
-	ab = emalloc(max_abbr_len + 1);
+	ab = xmalloc(max_abbr_len + 1);
-	envvar = emalloc(max_envvar_len + 1);
+	envvar = xmalloc(max_envvar_len + 1);
 	INITIALIZE(untiltime);
 	INITIALIZE(starttime);
 	/*
@@ -3972,7 +4008,7 @@ mkdirs(char const *argname, bool ancestors)
 	if (Dflag)
 		return;
 
-	char *name = estrdup(argname);
+	char *name = xstrdup(argname);
 	char *cp = name;
 
 	/* On MS-Windows systems, do not worry about drive letters or