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authorEitan Adler <eadler@FreeBSD.org>2018-08-12 22:06:35 +0000
committerEitan Adler <eadler@FreeBSD.org>2018-08-12 22:06:35 +0000
commitdea597b2df99e5e6fb7b916b835bf2033e997924 (patch)
tree20898106941a60ca503628059c4cfc37f61c6956
downloadsrc-vendor/tzdb.tar.gz
src-vendor/tzdb.zip
vendor/tzdb: reimport IANA database+code in a standard layoutvendor/tzdb/tzcode2018evendor/tzdb
I am using a new directory since the layout of both the vendor area and contrib/ need to be changed. This is a recommit of r337683 with only code.
Notes
Notes: svn path=/vendor/tzdb/dist/; revision=337694 svn path=/vendor/tzdb/tzcode2018e/; revision=337695; tag=vendor/tzdb/tzcode2018e
-rw-r--r--CONTRIBUTING89
-rw-r--r--LICENSE5
-rw-r--r--Makefile1013
-rw-r--r--NEWS4464
-rw-r--r--README52
-rw-r--r--asctime.c122
-rw-r--r--calendars173
-rw-r--r--date.1165
-rw-r--r--date.1.txt107
-rw-r--r--date.c237
-rw-r--r--difftime.c58
-rw-r--r--localtime.c2342
-rw-r--r--newctime.3317
-rw-r--r--newctime.3.txt171
-rw-r--r--newstrftime.3238
-rw-r--r--newstrftime.3.txt145
-rw-r--r--newtzset.3344
-rw-r--r--newtzset.3.txt199
-rw-r--r--private.h760
-rw-r--r--strftime.c633
-rw-r--r--theory.html1304
-rw-r--r--time2posix.3129
-rw-r--r--time2posix.3.txt76
-rw-r--r--tz-art.html610
-rw-r--r--tz-how-to.html682
-rw-r--r--tz-link.html953
-rw-r--r--tzfile.5190
-rw-r--r--tzfile.5.txt129
-rw-r--r--tzfile.h117
-rw-r--r--tzselect.8113
-rw-r--r--tzselect.8.txt77
-rw-r--r--tzselect.ksh561
-rw-r--r--version1
-rwxr-xr-xworkman.sh32
-rw-r--r--zdump.8226
-rw-r--r--zdump.8.txt144
-rw-r--r--zdump.c1116
-rw-r--r--zic.8599
-rw-r--r--zic.8.txt372
-rw-r--r--zic.c3286
40 files changed, 22351 insertions, 0 deletions
diff --git a/CONTRIBUTING b/CONTRIBUTING
new file mode 100644
index 000000000000..0cfc77f61853
--- /dev/null
+++ b/CONTRIBUTING
@@ -0,0 +1,89 @@
+Contributing to the tz code and data
+
+The time zone database is by no means authoritative: governments
+change timekeeping rules erratically and sometimes with little
+warning, the data entries do not cover all of civil time before
+1970, and undoubtedly errors remain in the code and data. Feel
+free to fill gaps or fix mistakes, and please email improvements
+to tz@iana.org for use in the future. In your email, please give
+reliable sources that reviewers can check.
+
+-----
+
+Developers can contribute technical changes to the source code and
+data as follows.
+
+To email small changes, please run a POSIX shell command like
+'diff -u old/europe new/europe >myfix.patch', and attach
+myfix.patch to the email.
+
+For more-elaborate changes, please read the theory.html file and browse
+the mailing list archives <https://mm.icann.org/pipermail/tz/> for
+examples of patches that tend to work well. Additions to
+data should contain commentary citing reliable sources as
+justification. Citations should use https: URLs if available.
+
+Please submit changes against either the latest release in
+<https://www.iana.org/time-zones> or the master branch of the development
+repository. The latter is preferred. If you use Git the following
+workflow may be helpful:
+
+ * Copy the development repository.
+
+ git clone https://github.com/eggert/tz.git
+ cd tz
+
+ * Get current with the master branch.
+
+ git checkout master
+ git pull
+
+ * Switch to a new branch for the changes. Choose a different
+ branch name for each change set.
+
+ git checkout -b mybranch
+
+ * Sleuth by using 'git blame'. For example, when fixing data for
+ Africa/Sao_Tome, if the command 'git blame africa' outputs a line
+ '2951fa3b (Paul Eggert 2018-01-08 09:03:13 -0800 1068) Zone
+ Africa/Sao_Tome 0:26:56 - LMT 1884', commit 2951fa3b should
+ provide some justification for the 'Zone Africa/Sao_Tome' line.
+
+ * Edit source files. Include commentary that justifies the
+ changes by citing reliable sources.
+
+ * Debug the changes, e.g.:
+
+ make check
+ make install
+ ./zdump -v America/Los_Angeles
+
+ * For each separable change, commit it in the new branch, e.g.:
+
+ git add northamerica
+ git commit
+
+ See recent 'git log' output for the commit-message style.
+
+ * Create patch files 0001-*, 0002-*, ...
+
+ git format-patch master
+
+ * After reviewing the patch files, send the patches to tz@iana.org
+ for others to review.
+
+ git send-email master
+
+ For an archived example of such an email, see
+ <https://mm.icann.org/pipermail/tz/2018-February/026122.html>.
+
+ * Start anew by getting current with the master branch again
+ (the second step above).
+
+Please do not create issues or pull requests on GitHub, as the
+proper procedure for proposing and distributing patches is via
+email as illustrated above.
+
+-----
+
+This file is in the public domain.
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 000000000000..8ba4399c622d
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,5 @@
+Unless specified below, all files in the tz code and data (including
+this LICENSE file) are in the public domain.
+
+If the files date.c, newstrftime.3, and strftime.c are present, they
+contain material derived from BSD and use the BSD 3-clause license.
diff --git a/Makefile b/Makefile
new file mode 100644
index 000000000000..21fa4889a3e7
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,1013 @@
+# This file is in the public domain, so clarified as of
+# 2009-05-17 by Arthur David Olson.
+
+# Package name for the code distribution.
+PACKAGE= tzcode
+
+# Version number for the distribution, overridden in the 'tarballs' rule below.
+VERSION= unknown
+
+# Email address for bug reports.
+BUGEMAIL= tz@iana.org
+
+# Choose source data features. To get new features right away, use:
+# DATAFORM= vanguard
+# To wait a while before using new features, to give downstream users
+# time to upgrade zic (the default), use:
+# DATAFORM= main
+# To wait even longer for new features, use:
+# DATAFORM= rearguard
+DATAFORM= main
+
+# Change the line below for your time zone (after finding the zone you want in
+# the time zone files, or adding it to a time zone file).
+# Alternatively, if you discover you've got the wrong time zone, you can just
+# zic -l rightzone
+# to correct things.
+# Use the command
+# make zonenames
+# to get a list of the values you can use for LOCALTIME.
+
+LOCALTIME= GMT
+
+# If you want something other than Eastern United States time as a template
+# for handling POSIX-style time zone environment variables,
+# change the line below (after finding the zone you want in the
+# time zone files, or adding it to a time zone file).
+# When a POSIX-style environment variable is handled, the rules in the
+# template file are used to determine "spring forward" and "fall back" days and
+# times; the environment variable itself specifies UT offsets of standard and
+# daylight saving time.
+# Alternatively, if you discover you've got the wrong time zone, you can just
+# zic -p rightzone
+# to correct things.
+# Use the command
+# make zonenames
+# to get a list of the values you can use for POSIXRULES.
+# If you want POSIX compatibility, use "America/New_York".
+
+POSIXRULES= America/New_York
+
+# Also see TZDEFRULESTRING below, which takes effect only
+# if the time zone files cannot be accessed.
+
+
+# Installation locations.
+#
+# The defaults are suitable for Debian, except that if REDO is
+# posix_right or right_posix then files that Debian puts under
+# /usr/share/zoneinfo/posix and /usr/share/zoneinfo/right are instead
+# put under /usr/share/zoneinfo-posix and /usr/share/zoneinfo-leaps,
+# respectively. Problems with the Debian approach are discussed in
+# the commentary for the right_posix rule (below).
+
+# Destination directory, which can be used for staging.
+# 'make DESTDIR=/stage install' installs under /stage (e.g., to
+# /stage/etc/localtime instead of to /etc/localtime). Files under
+# /stage are not intended to work as-is, but can be copied by hand to
+# the root directory later. If DESTDIR is empty, 'make install' does
+# not stage, but installs directly into production locations.
+DESTDIR =
+
+# Everything is installed into subdirectories of TOPDIR, and used there.
+# TOPDIR should be empty (meaning the root directory),
+# or a directory name that does not end in "/".
+# TOPDIR should be empty or an absolute name unless you're just testing.
+TOPDIR =
+
+# The default local time zone is taken from the file TZDEFAULT.
+TZDEFAULT = $(TOPDIR)/etc/localtime
+
+# The subdirectory containing installed program and data files, and
+# likewise for installed files that can be shared among architectures.
+# These should be relative file names.
+USRDIR = usr
+USRSHAREDIR = $(USRDIR)/share
+
+# "Compiled" time zone information is placed in the "TZDIR" directory
+# (and subdirectories).
+# TZDIR_BASENAME should not contain "/" and should not be ".", ".." or empty.
+TZDIR_BASENAME= zoneinfo
+TZDIR = $(TOPDIR)/$(USRSHAREDIR)/$(TZDIR_BASENAME)
+
+# The "tzselect" and (if you do "make INSTALL") "date" commands go in:
+BINDIR = $(TOPDIR)/$(USRDIR)/bin
+
+# The "zdump" command goes in:
+ZDUMPDIR = $(BINDIR)
+
+# The "zic" command goes in:
+ZICDIR = $(TOPDIR)/$(USRDIR)/sbin
+
+# Manual pages go in subdirectories of. . .
+MANDIR = $(TOPDIR)/$(USRSHAREDIR)/man
+
+# Library functions are put in an archive in LIBDIR.
+LIBDIR = $(TOPDIR)/$(USRDIR)/lib
+
+
+# Types to try, as an alternative to time_t. int64_t should be first.
+TIME_T_ALTERNATIVES = int64_t int32_t uint32_t uint64_t
+
+# If you want only POSIX time, with time values interpreted as
+# seconds since the epoch (not counting leap seconds), use
+# REDO= posix_only
+# below. If you want only "right" time, with values interpreted
+# as seconds since the epoch (counting leap seconds), use
+# REDO= right_only
+# below. If you want both sets of data available, with leap seconds not
+# counted normally, use
+# REDO= posix_right
+# below. If you want both sets of data available, with leap seconds counted
+# normally, use
+# REDO= right_posix
+# below. POSIX mandates that leap seconds not be counted; for compatibility
+# with it, use "posix_only" or "posix_right". Use POSIX time on systems with
+# leap smearing; this can work better than unsmeared "right" time with
+# applications that are not leap second aware, and is closer to unsmeared
+# "right" time than unsmeared POSIX time is (e.g., 0.5 vs 1.0 s max error).
+
+REDO= posix_right
+
+# To install data in text form that has all the information of the binary data,
+# (optionally incorporating leap second information), use
+# TZDATA_TEXT= tzdata.zi leapseconds
+# To install text data without leap second information (e.g., because
+# REDO='posix_only'), use
+# TZDATA_TEXT= tzdata.zi
+# To avoid installing text data, use
+# TZDATA_TEXT=
+
+TZDATA_TEXT= leapseconds tzdata.zi
+
+# For backward-compatibility links for old zone names, use
+# BACKWARD= backward
+# If you also want the link US/Pacific-New, even though it is confusing
+# and is planned to be removed from the database eventually, use
+# BACKWARD= backward pacificnew
+# To omit these links, use
+# BACKWARD=
+
+BACKWARD= backward
+
+# If you want out-of-scope and often-wrong data from the file 'backzone', use
+# PACKRATDATA= backzone
+# To omit this data, use
+# PACKRATDATA=
+
+PACKRATDATA=
+
+# The name of a locale using the UTF-8 encoding, used during self-tests.
+# The tests are skipped if the name does not appear to work on this system.
+
+UTF8_LOCALE= en_US.utf8
+
+# Since "." may not be in PATH...
+
+YEARISTYPE= ./yearistype
+
+# Non-default libraries needed to link.
+LDLIBS=
+
+# Add the following to the end of the "CFLAGS=" line as needed to override
+# defaults specified in the source code. "-DFOO" is equivalent to "-DFOO=1".
+# -DBIG_BANG=-9999999LL if the Big Bang occurred at time -9999999 (see zic.c)
+# -DDEPRECATE_TWO_DIGIT_YEARS for optional runtime warnings about strftime
+# formats that generate only the last two digits of year numbers
+# -DEPOCH_LOCAL if the 'time' function returns local time not UT
+# -DEPOCH_OFFSET=N if the 'time' function returns a value N greater
+# than what POSIX specifies, assuming local time is UT.
+# For example, N is 252460800 on AmigaOS.
+# -DHAVE_DECL_ASCTIME_R=0 if <time.h> does not declare asctime_r
+# -DHAVE_DECL_ENVIRON if <unistd.h> declares 'environ'
+# -DHAVE_DIRECT_H if mkdir needs <direct.h> (MS-Windows)
+# -DHAVE_GENERIC=0 if _Generic does not work
+# -DHAVE_GETTEXT if 'gettext' works (e.g., GNU/Linux, FreeBSD, Solaris)
+# -DHAVE_INCOMPATIBLE_CTIME_R if your system's time.h declares
+# ctime_r and asctime_r incompatibly with the POSIX standard
+# (Solaris when _POSIX_PTHREAD_SEMANTICS is not defined).
+# -DHAVE_INTTYPES_H if you have a non-C99 compiler with <inttypes.h>
+# -DHAVE_LINK=0 if your system lacks a link function
+# -DHAVE_LOCALTIME_R=0 if your system lacks a localtime_r function
+# -DHAVE_LOCALTIME_RZ=0 if you do not want zdump to use localtime_rz
+# localtime_rz can make zdump significantly faster, but is nonstandard.
+# -DHAVE_POSIX_DECLS=0 if your system's include files do not declare
+# functions like 'link' or variables like 'tzname' required by POSIX
+# -DHAVE_SNPRINTF=0 if your system lacks the snprintf function
+# -DHAVE_STDBOOL_H if you have a non-C99 compiler with <stdbool.h>
+# -DHAVE_STDINT_H if you have a non-C99 compiler with <stdint.h>
+# -DHAVE_STRFTIME_L if <time.h> declares locale_t and strftime_l
+# -DHAVE_STRDUP=0 if your system lacks the strdup function
+# -DHAVE_STRTOLL=0 if your system lacks the strtoll function
+# -DHAVE_SYMLINK=0 if your system lacks the symlink function
+# -DHAVE_SYS_STAT_H=0 if your compiler lacks a <sys/stat.h>
+# -DHAVE_SYS_WAIT_H=0 if your compiler lacks a <sys/wait.h>
+# -DHAVE_TZSET=0 if your system lacks a tzset function
+# -DHAVE_UNISTD_H=0 if your compiler lacks a <unistd.h>
+# -Dlocale_t=XXX if your system uses XXX instead of locale_t
+# -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
+# -DSUPPRESS_TZDIR to not prepend TZDIR to file names; this has
+# security implications and is not recommended for general use
+# -DTHREAD_SAFE to make localtime.c thread-safe, as POSIX requires;
+# not needed by the main-program tz code, which is single-threaded.
+# Append other compiler flags as needed, e.g., -pthread on GNU/Linux.
+# -Dtime_tz=\"T\" to use T as the time_t type, rather than the system time_t
+# This is intended for internal use only; it mangles external names.
+# -DTZ_DOMAIN=\"foo\" to use "foo" for gettext domain name; default is "tz"
+# -DTZ_DOMAINDIR=\"/path\" to use "/path" for gettext directory;
+# the default is system-supplied, typically "/usr/lib/locale"
+# -DTZDEFRULESTRING=\",date/time,date/time\" to default to the specified
+# DST transitions if the time zone files cannot be accessed
+# -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
+# Also set TZDOBJS=zdump.o and CHECK_TIME_T_ALTERNATIVES= below.
+# -DZIC_MAX_ABBR_LEN_WO_WARN=3
+# (or some other number) to set the maximum time zone abbreviation length
+# that zic will accept without a warning (the default is 6)
+# $(GCC_DEBUG_FLAGS) if you are using recent GCC and want lots of checking
+# Select instrumentation via "make GCC_INSTRUMENT='whatever'".
+GCC_INSTRUMENT = \
+ -fsanitize=undefined -fsanitize-address-use-after-scope \
+ -fsanitize-undefined-trap-on-error -fstack-protector
+GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
+ $(GCC_INSTRUMENT) \
+ -Wall -Wextra \
+ -Walloc-size-larger-than=100000 -Warray-bounds=2 \
+ -Wbad-function-cast -Wcast-align=strict -Wdate-time \
+ -Wdeclaration-after-statement -Wdouble-promotion \
+ -Wformat=2 -Wformat-overflow=2 -Wformat-signedness -Wformat-truncation \
+ -Winit-self -Wjump-misses-init -Wlogical-op \
+ -Wmissing-declarations -Wmissing-prototypes -Wnested-externs \
+ -Wold-style-definition -Woverlength-strings -Wpointer-arith \
+ -Wshadow -Wshift-overflow=2 -Wstrict-prototypes -Wstringop-overflow=4 \
+ -Wstringop-truncation -Wsuggest-attribute=cold \
+ -Wsuggest-attribute=const -Wsuggest-attribute=format \
+ -Wsuggest-attribute=malloc \
+ -Wsuggest-attribute=noreturn -Wsuggest-attribute=pure \
+ -Wtrampolines -Wundef -Wuninitialized -Wunused \
+ -Wvariadic-macros -Wvla -Wwrite-strings \
+ -Wno-address -Wno-format-nonliteral -Wno-sign-compare \
+ -Wno-type-limits -Wno-unused-parameter
+#
+# 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),
+# add the name to a define such as
+# -DTM_GMTOFF=tm_gmtoff
+# to the end of the "CFLAGS=" line. If not defined, the code attempts to
+# guess TM_GMTOFF from other macros; define NO_TM_GMTOFF to suppress this.
+# Similarly, if your system has a "zone abbreviation" field, define
+# -DTM_ZONE=tm_zone
+# and define NO_TM_ZONE to suppress any guessing. These two fields are not
+# required by POSIX, but are widely available on GNU/Linux and BSD systems.
+#
+# The next batch of options control support for external variables
+# exported by tzcode. In practice these variables are less useful
+# than TM_GMTOFF and TM_ZONE. However, most of them are standardized.
+# #
+# # To omit or support the external variable "tzname", add one of:
+# # -DHAVE_TZNAME=0
+# # -DHAVE_TZNAME=1
+# # to the "CFLAGS=" line. "tzname" is required by POSIX 1988 and later.
+# # If not defined, the code attempts to guess HAVE_TZNAME from other macros.
+# # Warning: unless time_tz is also defined, HAVE_TZNAME=1 can cause
+# # crashes when combined with some platforms' standard libraries,
+# # presumably due to memory allocation issues.
+# #
+# # To omit or support the external variables "timezone" and "daylight", add
+# # -DUSG_COMPAT=0
+# # -DUSG_COMPAT=1
+# # to the "CFLAGS=" line; "timezone" and "daylight" are inspired by
+# # Unix Systems Group code and are required by POSIX 2008 (with XSI) and later.
+# # If not defined, the code attempts to guess USG_COMPAT from other macros.
+# #
+# # To support the external variable "altzone", add
+# # -DALTZONE
+# # to the end of the "CFLAGS=" line; although "altzone" appeared in
+# # System V Release 3.1 it has not been standardized.
+#
+# If you want functions that were inspired by early versions of X3J11's work,
+# add
+# -DSTD_INSPIRED
+# to the end of the "CFLAGS=" line. This arranges for the functions
+# "tzsetwall", "offtime", "timelocal", "timegm", "timeoff",
+# "posix2time", and "time2posix" to be added to the time conversion library.
+# "tzsetwall" is like "tzset" except that it arranges for local wall clock
+# time (rather than the time specified in the TZ environment variable)
+# to be used.
+# "offtime" is like "gmtime" except that it accepts a second (long) argument
+# that gives an offset to add to the time_t when converting it.
+# "timelocal" is equivalent to "mktime".
+# "timegm" is like "timelocal" except that it turns a struct tm into
+# a time_t using UT (rather than local time as "timelocal" does).
+# "timeoff" is like "timegm" except that it accepts a second (long) argument
+# that gives an offset to use when converting to a time_t.
+# "posix2time" and "time2posix" are described in an included manual page.
+# X3J11's work does not describe any of these functions.
+# Sun has provided "tzsetwall", "timelocal", and "timegm" in SunOS 4.0.
+# These functions may well disappear in future releases of the time
+# conversion package.
+#
+# If you don't want functions that were inspired by NetBSD, add
+# -DNETBSD_INSPIRED=0
+# to the end of the "CFLAGS=" line. Otherwise, the functions
+# "localtime_rz", "mktime_z", "tzalloc", and "tzfree" are added to the
+# time library, and if STD_INSPIRED is also defined the functions
+# "posix2time_z" and "time2posix_z" are added as well.
+# The functions ending in "_z" (or "_rz") are like their unsuffixed
+# (or suffixed-by-"_r") counterparts, except with an extra first
+# argument of opaque type timezone_t that specifies the time zone.
+# "tzalloc" allocates a timezone_t value, and "tzfree" frees it.
+#
+# If you want to allocate state structures in localtime, add
+# -DALL_STATE
+# to the end of the "CFLAGS=" line. Storage is obtained by calling malloc.
+#
+# NIST-PCTS:151-2, Version 1.4, (1993-12-03) is a test suite put
+# out by the National Institute of Standards and Technology
+# which claims to test C and Posix conformance. If you want to pass PCTS, add
+# -DPCTS
+# to the end of the "CFLAGS=" line.
+#
+# If you want strict compliance with XPG4 as of 1994-04-09, add
+# -DXPG4_1994_04_09
+# to the end of the "CFLAGS=" line. This causes "strftime" to always return
+# 53 as a week number (rather than 52 or 53) for January days before
+# January's first Monday when a "%V" format is used and January 1
+# falls on a Friday, Saturday, or Sunday.
+
+CFLAGS=
+
+# Linker flags. Default to $(LFLAGS) for backwards compatibility
+# to release 2012h and earlier.
+
+LDFLAGS= $(LFLAGS)
+
+# For leap seconds, this Makefile uses LEAPSECONDS='-L leapseconds' in
+# submake command lines. The default is no leap seconds.
+
+LEAPSECONDS=
+
+# The zic command and its arguments.
+
+zic= ./zic
+ZIC= $(zic) $(ZFLAGS)
+
+ZFLAGS=
+
+# How to use zic to install tz binary files.
+
+ZIC_INSTALL= $(ZIC) -d '$(DESTDIR)$(TZDIR)' $(LEAPSECONDS)
+
+# The name of a Posix-compliant 'awk' on your system.
+AWK= awk
+
+# The full path name of a Posix-compliant shell, preferably one that supports
+# the Korn shell's 'select' statement as an extension.
+# These days, Bash is the most popular.
+# It should be OK to set this to /bin/sh, on platforms where /bin/sh
+# lacks 'select' or doesn't completely conform to Posix, but /bin/bash
+# is typically nicer if it works.
+KSHELL= /bin/bash
+
+# The path where SGML DTDs are kept and the catalog file(s) to use when
+# validating. The default should work on both Debian and Red Hat.
+SGML_TOPDIR= /usr
+SGML_DTDDIR= $(SGML_TOPDIR)/share/xml/w3c-sgml-lib/schema/dtd
+SGML_SEARCH_PATH= $(SGML_DTDDIR)/REC-html401-19991224
+SGML_CATALOG_FILES= \
+ $(SGML_TOPDIR)/share/doc/w3-recs/html/www.w3.org/TR/1999/REC-html401-19991224/HTML4.cat:$(SGML_TOPDIR)/share/sgml/html/4.01/HTML4.cat
+
+# The name, arguments and environment of a program to validate your web pages.
+# See <http://openjade.sourceforge.net/doc/> for a validator, and
+# <https://validator.w3.org/source/> for a validation library.
+# Set VALIDATE=':' if you do not have such a program.
+VALIDATE = nsgmls
+VALIDATE_FLAGS = -s -B -wall -wno-unused-param
+VALIDATE_ENV = \
+ SGML_CATALOG_FILES='$(SGML_CATALOG_FILES)' \
+ SGML_SEARCH_PATH='$(SGML_SEARCH_PATH)' \
+ SP_CHARSET_FIXED=YES \
+ SP_ENCODING=UTF-8
+
+# This expensive test requires USE_LTZ.
+# To suppress it, define this macro to be empty.
+CHECK_TIME_T_ALTERNATIVES = check_time_t_alternatives
+
+# SAFE_CHAR is a regular expression that matches a safe character.
+# Some parts of this distribution are limited to safe characters;
+# others can use any UTF-8 character.
+# For now, the safe characters are a safe subset of ASCII.
+# The caller must set the shell variable 'sharp' to the character '#',
+# since Makefile macros cannot contain '#'.
+# TAB_CHAR is a single tab character, in single quotes.
+TAB_CHAR= ' '
+SAFE_CHARSET1= $(TAB_CHAR)' !\"'$$sharp'$$%&'\''()*+,./0123456789:;<=>?@'
+SAFE_CHARSET2= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\^_`'
+SAFE_CHARSET3= 'abcdefghijklmnopqrstuvwxyz{|}~'
+SAFE_CHARSET= $(SAFE_CHARSET1)$(SAFE_CHARSET2)$(SAFE_CHARSET3)
+SAFE_CHAR= '[]'$(SAFE_CHARSET)'-]'
+
+# Non-ASCII non-letters that OK_CHAR allows, as these characters are
+# useful in commentary. XEmacs 21.5.34 displays them correctly,
+# presumably because they are Latin-1.
+UNUSUAL_OK_CHARSET= °±½¾×
+
+# OK_CHAR matches any character allowed in the distributed files.
+# This is the same as SAFE_CHAR, except that UNUSUAL_OK_CHARSET and
+# multibyte letters are also allowed so that commentary can contain a
+# few safe symbols and people's names and can quote non-English sources.
+# Other non-letters are limited to ASCII renderings for the
+# convenience of maintainers using XEmacs 21.5.34, which by default
+# mishandles Unicode characters U+0100 and greater.
+OK_CHAR= '[][:alpha:]$(UNUSUAL_OK_CHARSET)'$(SAFE_CHARSET)'-]'
+
+# SAFE_LINE matches a line of safe characters.
+# SAFE_SHARP_LINE is similar, except any OK character can follow '#';
+# this is so that comments can contain non-ASCII characters.
+# OK_LINE matches a line of OK characters.
+SAFE_LINE= '^'$(SAFE_CHAR)'*$$'
+SAFE_SHARP_LINE='^'$(SAFE_CHAR)'*('$$sharp$(OK_CHAR)'*)?$$'
+OK_LINE= '^'$(OK_CHAR)'*$$'
+
+# Flags to give 'tar' when making a distribution.
+# Try to use flags appropriate for GNU tar.
+GNUTARFLAGS= --numeric-owner --owner=0 --group=0 --mode=go+u,go-w --sort=name
+TARFLAGS= `if tar $(GNUTARFLAGS) --version >/dev/null 2>&1; \
+ then echo $(GNUTARFLAGS); \
+ else :; \
+ fi`
+
+# Flags to give 'gzip' when making a distribution.
+GZIPFLAGS= -9n
+
+###############################################################################
+
+#MAKE= make
+
+cc= cc
+CC= $(cc) -DTZDIR='"$(TZDIR)"'
+
+AR= ar
+
+# ':' on typical hosts; 'ranlib' on the ancient hosts that still need ranlib.
+RANLIB= :
+
+TZCOBJS= zic.o
+TZDOBJS= zdump.o localtime.o asctime.o strftime.o
+DATEOBJS= date.o localtime.o strftime.o asctime.o
+LIBSRCS= localtime.c asctime.c difftime.c
+LIBOBJS= localtime.o asctime.o difftime.o
+HEADERS= tzfile.h private.h
+NONLIBSRCS= zic.c zdump.c
+NEWUCBSRCS= date.c strftime.c
+SOURCES= $(HEADERS) $(LIBSRCS) $(NONLIBSRCS) $(NEWUCBSRCS) \
+ tzselect.ksh workman.sh
+MANS= newctime.3 newstrftime.3 newtzset.3 time2posix.3 \
+ tzfile.5 tzselect.8 zic.8 zdump.8
+MANTXTS= newctime.3.txt newstrftime.3.txt newtzset.3.txt \
+ time2posix.3.txt \
+ tzfile.5.txt tzselect.8.txt zic.8.txt zdump.8.txt \
+ date.1.txt
+COMMON= calendars CONTRIBUTING LICENSE Makefile \
+ NEWS README theory.html version
+WEB_PAGES= tz-art.html tz-how-to.html tz-link.html
+DOCS= $(MANS) date.1 $(MANTXTS) $(WEB_PAGES)
+PRIMARY_YDATA= africa antarctica asia australasia \
+ europe northamerica southamerica
+YDATA= $(PRIMARY_YDATA) etcetera
+NDATA= systemv factory
+TDATA_TO_CHECK= $(YDATA) $(NDATA) backward pacificnew
+TDATA= $(YDATA) $(NDATA) $(BACKWARD)
+ZONETABLES= zone1970.tab zone.tab
+TABDATA= iso3166.tab $(TZDATA_TEXT) $(ZONETABLES)
+LEAP_DEPS= leapseconds.awk leap-seconds.list
+TZDATA_ZI_DEPS= ziguard.awk zishrink.awk version $(TDATA) $(PACKRATDATA)
+DSTDATA_ZI_DEPS= ziguard.awk $(TDATA) $(PACKRATDATA)
+DATA= $(TDATA_TO_CHECK) backzone iso3166.tab leap-seconds.list \
+ leapseconds yearistype.sh $(ZONETABLES)
+AWK_SCRIPTS= checklinks.awk checktab.awk leapseconds.awk \
+ ziguard.awk zishrink.awk
+MISC= $(AWK_SCRIPTS) zoneinfo2tdf.pl
+TZS_YEAR= 2050
+TZS= to$(TZS_YEAR).tzs
+TZS_NEW= to$(TZS_YEAR)new.tzs
+TZS_DEPS= $(PRIMARY_YDATA) asctime.c localtime.c \
+ private.h tzfile.h zdump.c zic.c
+ENCHILADA= $(COMMON) $(DOCS) $(SOURCES) $(DATA) $(MISC) $(TZS) tzdata.zi
+
+# Consult these files when deciding whether to rebuild the 'version' file.
+# This list is not the same as the output of 'git ls-files', since
+# .gitignore is not distributed.
+VERSION_DEPS= \
+ calendars CONTRIBUTING LICENSE Makefile NEWS README \
+ africa antarctica asctime.c asia australasia \
+ backward backzone \
+ checklinks.awk checktab.awk \
+ date.1 date.c difftime.c \
+ etcetera europe factory iso3166.tab \
+ leap-seconds.list leapseconds.awk localtime.c \
+ newctime.3 newstrftime.3 newtzset.3 northamerica \
+ pacificnew private.h \
+ southamerica strftime.c systemv theory.html \
+ time2posix.3 tz-art.html tz-how-to.html tz-link.html \
+ tzfile.5 tzfile.h tzselect.8 tzselect.ksh \
+ workman.sh yearistype.sh \
+ zdump.8 zdump.c zic.8 zic.c \
+ ziguard.awk zishrink.awk \
+ zone.tab zone1970.tab zoneinfo2tdf.pl
+
+# And for the benefit of csh users on systems that assume the user
+# shell should be used to handle commands in Makefiles. . .
+
+SHELL= /bin/sh
+
+all: tzselect yearistype zic zdump libtz.a $(TABDATA) \
+ vanguard.zi main.zi rearguard.zi
+
+ALL: all date $(ENCHILADA)
+
+install: all $(DATA) $(REDO) $(MANS)
+ mkdir -p '$(DESTDIR)$(BINDIR)' \
+ '$(DESTDIR)$(ZDUMPDIR)' '$(DESTDIR)$(ZICDIR)' \
+ '$(DESTDIR)$(LIBDIR)' \
+ '$(DESTDIR)$(MANDIR)/man3' '$(DESTDIR)$(MANDIR)/man5' \
+ '$(DESTDIR)$(MANDIR)/man8'
+ $(ZIC_INSTALL) -l $(LOCALTIME) -p $(POSIXRULES) \
+ -t '$(DESTDIR)$(TZDEFAULT)'
+ cp -f $(TABDATA) '$(DESTDIR)$(TZDIR)/.'
+ cp tzselect '$(DESTDIR)$(BINDIR)/.'
+ cp zdump '$(DESTDIR)$(ZDUMPDIR)/.'
+ cp zic '$(DESTDIR)$(ZICDIR)/.'
+ cp libtz.a '$(DESTDIR)$(LIBDIR)/.'
+ $(RANLIB) '$(DESTDIR)$(LIBDIR)/libtz.a'
+ cp -f newctime.3 newtzset.3 '$(DESTDIR)$(MANDIR)/man3/.'
+ cp -f tzfile.5 '$(DESTDIR)$(MANDIR)/man5/.'
+ cp -f tzselect.8 zdump.8 zic.8 '$(DESTDIR)$(MANDIR)/man8/.'
+
+INSTALL: ALL install date.1
+ mkdir -p '$(DESTDIR)$(BINDIR)' '$(DESTDIR)$(MANDIR)/man1'
+ cp date '$(DESTDIR)$(BINDIR)/.'
+ cp -f date.1 '$(DESTDIR)$(MANDIR)/man1/.'
+
+version: $(VERSION_DEPS)
+ { (type git) >/dev/null 2>&1 && \
+ V=`git describe --match '[0-9][0-9][0-9][0-9][a-z]*' \
+ --abbrev=7 --dirty` || \
+ V='$(VERSION)'; } && \
+ printf '%s\n' "$$V" >$@.out
+ mv $@.out $@
+
+# These files can be tailored by setting BACKWARD, PACKRATDATA, etc.
+vanguard.zi main.zi rearguard.zi: $(DSTDATA_ZI_DEPS)
+ $(AWK) -v DATAFORM=`expr $@ : '\(.*\).zi'` -f ziguard.awk \
+ $(TDATA) $(PACKRATDATA) >$@.out
+ mv $@.out $@
+tzdata.zi: $(DATAFORM).zi version
+ version=`sed 1q version` && \
+ LC_ALL=C $(AWK) -v version="$$version" -f zishrink.awk \
+ $(DATAFORM).zi >$@.out
+ mv $@.out $@
+
+version.h: version
+ VERSION=`cat version` && printf '%s\n' \
+ 'static char const PKGVERSION[]="($(PACKAGE)) ";' \
+ "static char const TZVERSION[]=\"$$VERSION\";" \
+ 'static char const REPORT_BUGS_TO[]="$(BUGEMAIL)";' \
+ >$@.out
+ mv $@.out $@
+
+zdump: $(TZDOBJS)
+ $(CC) -o $@ $(CFLAGS) $(LDFLAGS) $(TZDOBJS) $(LDLIBS)
+
+zic: $(TZCOBJS)
+ $(CC) -o $@ $(CFLAGS) $(LDFLAGS) $(TZCOBJS) $(LDLIBS)
+
+yearistype: yearistype.sh
+ cp yearistype.sh yearistype
+ chmod +x yearistype
+
+leapseconds: $(LEAP_DEPS)
+ $(AWK) -f leapseconds.awk leap-seconds.list >$@.out
+ mv $@.out $@
+
+# Arguments to pass to submakes of install_data.
+# They can be overridden by later submake arguments.
+INSTALLARGS = \
+ BACKWARD='$(BACKWARD)' \
+ DESTDIR='$(DESTDIR)' \
+ LEAPSECONDS='$(LEAPSECONDS)' \
+ PACKRATDATA='$(PACKRATDATA)' \
+ TZDEFAULT='$(TZDEFAULT)' \
+ TZDIR='$(TZDIR)' \
+ YEARISTYPE='$(YEARISTYPE)' \
+ ZIC='$(ZIC)'
+
+# 'make install_data' installs one set of tz binary files.
+install_data: zic leapseconds yearistype tzdata.zi
+ $(ZIC_INSTALL) tzdata.zi
+
+posix_only:
+ $(MAKE) $(INSTALLARGS) LEAPSECONDS= install_data
+
+right_only:
+ $(MAKE) $(INSTALLARGS) LEAPSECONDS='-L leapseconds' \
+ install_data
+
+# In earlier versions of this makefile, the other two directories were
+# subdirectories of $(TZDIR). However, this led to configuration errors.
+# For example, with posix_right under the earlier scheme,
+# TZ='right/Australia/Adelaide' got you localtime with leap seconds,
+# but gmtime without leap seconds, which led to problems with applications
+# like sendmail that subtract gmtime from localtime.
+# Therefore, the other two directories are now siblings of $(TZDIR).
+# You must replace all of $(TZDIR) to switch from not using leap seconds
+# to using them, or vice versa.
+right_posix: right_only
+ rm -fr '$(DESTDIR)$(TZDIR)-leaps'
+ ln -s '$(TZDIR_BASENAME)' '$(DESTDIR)$(TZDIR)-leaps' || \
+ $(MAKE) $(INSTALLARGS) TZDIR='$(TZDIR)-leaps' right_only
+ $(MAKE) $(INSTALLARGS) TZDIR='$(TZDIR)-posix' posix_only
+
+posix_right: posix_only
+ rm -fr '$(DESTDIR)$(TZDIR)-posix'
+ ln -s '$(TZDIR_BASENAME)' '$(DESTDIR)$(TZDIR)-posix' || \
+ $(MAKE) $(INSTALLARGS) TZDIR='$(TZDIR)-posix' posix_only
+ $(MAKE) $(INSTALLARGS) TZDIR='$(TZDIR)-leaps' right_only
+
+# This obsolescent rule is present for backwards compatibility with
+# tz releases 2014g through 2015g. It should go away eventually.
+posix_packrat:
+ $(MAKE) $(INSTALLARGS) PACKRATDATA=backzone posix_only
+
+zones: $(REDO)
+
+# dummy.zd is not a real file; it is mentioned here only so that the
+# top-level 'make' does not have a syntax error.
+ZDS = dummy.zd
+# Rule used only by submakes invoked by the $(TZS_NEW) rule.
+# It is separate so that GNU 'make -j' can run instances in parallel.
+$(ZDS): zdump
+ ./zdump -i -c $(TZS_YEAR) '$(wd)/'$$(expr $@ : '\(.*\).zd') >$@
+
+$(TZS_NEW): tzdata.zi zdump zic
+ rm -fr tzs.dir
+ mkdir tzs.dir
+ $(zic) -d tzs.dir tzdata.zi
+ $(AWK) '/^L/{print "Link\t" $$2 "\t" $$3}' \
+ tzdata.zi | LC_ALL=C sort >$@.out
+ wd=`pwd` && \
+ set x `$(AWK) '/^Z/{print "tzs.dir/" $$2 ".zd"}' tzdata.zi \
+ | LC_ALL=C sort -t . -k 2,2` && \
+ shift && \
+ ZDS=$$* && \
+ $(MAKE) wd="$$wd" TZS_YEAR=$(TZS_YEAR) ZDS="$$ZDS" $$ZDS && \
+ sed 's,^TZ=".*tzs\.dir/,TZ=",' $$ZDS >>$@.out
+ rm -fr tzs.dir
+ mv $@.out $@
+
+# If $(TZS) does not already exist (e.g., old-format tarballs), create it.
+# If it exists but 'make check_tzs' fails, a maintainer should inspect the
+# failed output and fix the inconsistency, perhaps by running 'make force_tzs'.
+$(TZS):
+ $(MAKE) force_tzs
+
+force_tzs: $(TZS_NEW)
+ cp $(TZS_NEW) $(TZS)
+
+libtz.a: $(LIBOBJS)
+ rm -f $@
+ $(AR) -rc $@ $(LIBOBJS)
+ $(RANLIB) $@
+
+date: $(DATEOBJS)
+ $(CC) -o $@ $(CFLAGS) $(LDFLAGS) $(DATEOBJS) $(LDLIBS)
+
+tzselect: tzselect.ksh version
+ VERSION=`cat version` && sed \
+ -e 's|#!/bin/bash|#!$(KSHELL)|g' \
+ -e 's|AWK=[^}]*|AWK=$(AWK)|g' \
+ -e 's|\(PKGVERSION\)=.*|\1='\''($(PACKAGE)) '\''|' \
+ -e 's|\(REPORT_BUGS_TO\)=.*|\1=$(BUGEMAIL)|' \
+ -e 's|TZDIR=[^}]*|TZDIR=$(TZDIR)|' \
+ -e 's|\(TZVERSION\)=.*|\1='"$$VERSION"'|' \
+ <$@.ksh >$@.out
+ chmod +x $@.out
+ mv $@.out $@
+
+check: check_character_set check_white_space check_links \
+ check_name_lengths check_sorted \
+ check_tables check_web check_zishrink check_tzs
+
+check_character_set: $(ENCHILADA)
+ test ! '$(UTF8_LOCALE)' || \
+ ! printf 'A\304\200B\n' | \
+ LC_ALL='$(UTF8_LOCALE)' grep -q '^A.B$$' >/dev/null 2>&1 || { \
+ LC_ALL='$(UTF8_LOCALE)' && export LC_ALL && \
+ sharp='#' && \
+ ! grep -Env $(SAFE_LINE) $(MANS) date.1 $(MANTXTS) \
+ $(MISC) $(SOURCES) $(WEB_PAGES) \
+ CONTRIBUTING LICENSE README \
+ version tzdata.zi && \
+ ! grep -Env $(SAFE_LINE)'|^UNUSUAL_OK_CHARSET='$(OK_CHAR)'*$$' \
+ Makefile && \
+ ! grep -Env $(SAFE_SHARP_LINE) $(TDATA_TO_CHECK) backzone \
+ leapseconds yearistype.sh zone.tab && \
+ ! grep -Env $(OK_LINE) $(ENCHILADA); \
+ }
+
+check_white_space: $(ENCHILADA)
+ patfmt=' \t|[\f\r\v]' && pat=`printf "$$patfmt\\n"` && \
+ ! grep -En "$$pat" $(ENCHILADA)
+ ! grep -n '[[:space:]]$$' \
+ $$(ls $(ENCHILADA) | grep -Fvx leap-seconds.list)
+
+PRECEDES_FILE_NAME = ^(Zone|Link[[:space:]]+[^[:space:]]+)[[:space:]]+
+FILE_NAME_COMPONENT_TOO_LONG = \
+ $(PRECEDES_FILE_NAME)[^[:space:]]*[^/[:space:]]{15}
+
+check_name_lengths: $(TDATA_TO_CHECK) backzone
+ ! grep -En '$(FILE_NAME_COMPONENT_TOO_LONG)' \
+ $(TDATA_TO_CHECK) backzone
+
+CHECK_CC_LIST = { n = split($$1,a,/,/); for (i=2; i<=n; i++) print a[1], a[i]; }
+
+check_sorted: backward backzone iso3166.tab zone.tab zone1970.tab
+ $(AWK) '/^Link/ {print $$3}' backward | LC_ALL=C sort -cu
+ $(AWK) '/^Zone/ {print $$2}' backzone | LC_ALL=C sort -cu
+ $(AWK) '/^[^#]/ {print $$1}' iso3166.tab | LC_ALL=C sort -cu
+ $(AWK) '/^[^#]/ {print $$1}' zone.tab | LC_ALL=C sort -c
+ $(AWK) '/^[^#]/ {print substr($$0, 1, 2)}' zone1970.tab | \
+ LC_ALL=C sort -c
+ $(AWK) '/^[^#]/ $(CHECK_CC_LIST)' zone1970.tab | \
+ LC_ALL=C sort -cu
+
+check_links: checklinks.awk $(TDATA_TO_CHECK) tzdata.zi
+ $(AWK) -f checklinks.awk $(TDATA_TO_CHECK)
+ $(AWK) -f checklinks.awk tzdata.zi
+
+check_tables: checktab.awk $(PRIMARY_YDATA) $(ZONETABLES)
+ for tab in $(ZONETABLES); do \
+ $(AWK) -f checktab.awk -v zone_table=$$tab $(PRIMARY_YDATA) \
+ || exit; \
+ done
+
+check_tzs: $(TZS) $(TZS_NEW)
+ diff -u $(TZS) $(TZS_NEW)
+
+# This checks only the HTML 4.01 strict page.
+# To check the the other pages, use <https://validator.w3.org/>.
+check_web: tz-how-to.html
+ $(VALIDATE_ENV) $(VALIDATE) $(VALIDATE_FLAGS) tz-how-to.html
+
+# Check that zishrink.awk does not alter the data, and that ziguard.awk
+# preserves main-format data.
+check_zishrink: zic leapseconds $(PACKRATDATA) $(TDATA) \
+ $(DATAFORM).zi tzdata.zi
+ for type in posix right; do \
+ mkdir -p time_t.dir/$$type time_t.dir/$$type-t \
+ time_t.dir/$$type-shrunk && \
+ case $$type in \
+ right) leap='-L leapseconds';; \
+ *) leap=;; \
+ esac && \
+ $(ZIC) $$leap -d time_t.dir/$$type $(DATAFORM).zi && \
+ case $(DATAFORM) in \
+ main) \
+ $(ZIC) $$leap -d time_t.dir/$$type-t $(TDATA) && \
+ $(AWK) '/^Rule/' $(TDATA) | \
+ $(ZIC) $$leap -d time_t.dir/$$type-t - \
+ $(PACKRATDATA) && \
+ diff -r time_t.dir/$$type time_t.dir/$$type-t;; \
+ esac && \
+ $(ZIC) $$leap -d time_t.dir/$$type-shrunk tzdata.zi && \
+ diff -r time_t.dir/$$type time_t.dir/$$type-shrunk || exit; \
+ done
+ rm -fr time_t.dir
+
+clean_misc:
+ rm -f core *.o *.out \
+ date tzselect version.h zdump zic yearistype libtz.a
+clean: clean_misc
+ rm -fr *.dir *.zi tzdb-*/ $(TZS_NEW)
+
+maintainer-clean: clean
+ @echo 'This command is intended for maintainers to use; it'
+ @echo 'deletes files that may need special tools to rebuild.'
+ rm -f leapseconds version $(MANTXTS) $(TZS) *.asc *.tar.*
+
+names:
+ @echo $(ENCHILADA)
+
+public: check check_public $(CHECK_TIME_T_ALTERNATIVES) \
+ tarballs signatures
+
+date.1.txt: date.1
+newctime.3.txt: newctime.3
+newstrftime.3.txt: newstrftime.3
+newtzset.3.txt: newtzset.3
+time2posix.3.txt: time2posix.3
+tzfile.5.txt: tzfile.5
+tzselect.8.txt: tzselect.8
+zdump.8.txt: zdump.8
+zic.8.txt: zic.8
+
+$(MANTXTS): workman.sh
+ LC_ALL=C sh workman.sh `expr $@ : '\(.*\)\.txt$$'` >$@.out
+ mv $@.out $@
+
+# Set the time stamps to those of the git repository, if available,
+# and if the files have not changed since then.
+# This uses GNU 'touch' syntax 'touch -d@N FILE',
+# where N is the number of seconds since 1970.
+# If git or GNU 'touch' is absent, don't bother to sync with git timestamps.
+# Also, set the timestamp of each prebuilt file like 'leapseconds'
+# to be the maximum of the files it depends on.
+set-timestamps.out: $(ENCHILADA)
+ rm -f $@
+ if (type git) >/dev/null 2>&1 && \
+ files=`git ls-files $(ENCHILADA)` && \
+ touch -md @1 test.out; then \
+ rm -f test.out && \
+ for file in $$files; do \
+ if git diff --quiet $$file; then \
+ time=`git log -1 --format='tformat:%ct' $$file` && \
+ touch -cmd @$$time $$file; \
+ else \
+ echo >&2 "$$file: warning: does not match repository"; \
+ fi || exit; \
+ done; \
+ fi
+ touch -cmr `ls -t $(LEAP_DEPS) | sed 1q` leapseconds
+ for file in `ls $(MANTXTS) | sed 's/\.txt$$//'`; do \
+ touch -cmr `ls -t $$file workman.sh | sed 1q` $$file.txt || \
+ exit; \
+ done
+ touch -cmr `ls -t $(TZDATA_ZI_DEPS) | sed 1q` tzdata.zi
+ touch -cmr `ls -t $(TZS_DEPS) | sed 1q` $(TZS)
+ touch -cmr `ls -t $(VERSION_DEPS) | sed 1q` version
+ touch $@
+
+# The zics below ensure that each data file can stand on its own.
+# We also do an all-files run to catch links to links.
+
+check_public:
+ $(MAKE) maintainer-clean
+ $(MAKE) CFLAGS='$(GCC_DEBUG_FLAGS)' ALL
+ mkdir -p public.dir
+ for i in $(TDATA_TO_CHECK) tzdata.zi; do \
+ $(zic) -v -d public.dir $$i 2>&1 || exit; \
+ done
+ $(zic) -v -d public.dir $(TDATA_TO_CHECK)
+ rm -fr public.dir
+
+# Check that the code works under various alternative
+# implementations of time_t.
+check_time_t_alternatives:
+ if diff -q Makefile Makefile 2>/dev/null; then \
+ quiet_option='-q'; \
+ else \
+ quiet_option=''; \
+ fi && \
+ wd=`pwd` && \
+ zones=`$(AWK) '/^[^#]/ { print $$3 }' <zone1970.tab` && \
+ for type in $(TIME_T_ALTERNATIVES); do \
+ mkdir -p time_t.dir/$$type && \
+ $(MAKE) clean_misc && \
+ $(MAKE) TOPDIR="$$wd/time_t.dir/$$type" \
+ CFLAGS='$(CFLAGS) -Dtime_tz='"'$$type'" \
+ REDO='$(REDO)' \
+ install && \
+ diff $$quiet_option -r \
+ time_t.dir/int64_t/etc \
+ time_t.dir/$$type/etc && \
+ diff $$quiet_option -r \
+ time_t.dir/int64_t/usr/share \
+ time_t.dir/$$type/usr/share && \
+ case $$type in \
+ int32_t) range=-2147483648,2147483647;; \
+ uint32_t) range=0,4294967296;; \
+ int64_t) continue;; \
+ *u*) range=0,10000000000;; \
+ *) range=-10000000000,10000000000;; \
+ esac && \
+ echo checking $$type zones ... && \
+ time_t.dir/int64_t/usr/bin/zdump -V -t $$range $$zones \
+ >time_t.dir/int64_t.out && \
+ time_t.dir/$$type/usr/bin/zdump -V -t $$range $$zones \
+ >time_t.dir/$$type.out && \
+ diff -u time_t.dir/int64_t.out time_t.dir/$$type.out \
+ || exit; \
+ done
+ rm -fr time_t.dir
+
+TRADITIONAL_ASC = \
+ tzcode$(VERSION).tar.gz.asc \
+ tzdata$(VERSION).tar.gz.asc
+ALL_ASC = $(TRADITIONAL_ASC) \
+ tzdata$(VERSION)-rearguard.tar.gz.asc \
+ tzdb-$(VERSION).tar.lz.asc
+
+tarballs traditional_tarballs signatures traditional_signatures: version
+ VERSION=`cat version` && \
+ $(MAKE) VERSION="$$VERSION" $@_version
+
+# These *_version rules are intended for use if VERSION is set by some
+# other means. Ordinarily these rules are used only by the above
+# non-_version rules, which set VERSION on the 'make' command line.
+tarballs_version: traditional_tarballs_version \
+ tzdata$(VERSION)-rearguard.tar.gz \
+ tzdb-$(VERSION).tar.lz
+traditional_tarballs_version: \
+ tzcode$(VERSION).tar.gz tzdata$(VERSION).tar.gz
+signatures_version: $(ALL_ASC)
+traditional_signatures_version: $(TRADITIONAL_ASC)
+
+tzcode$(VERSION).tar.gz: set-timestamps.out
+ LC_ALL=C && export LC_ALL && \
+ tar $(TARFLAGS) -cf - \
+ $(COMMON) $(DOCS) $(SOURCES) | \
+ gzip $(GZIPFLAGS) >$@.out
+ mv $@.out $@
+
+tzdata$(VERSION).tar.gz: set-timestamps.out
+ LC_ALL=C && export LC_ALL && \
+ tar $(TARFLAGS) -cf - $(COMMON) $(DATA) $(MISC) | \
+ gzip $(GZIPFLAGS) >$@.out
+ mv $@.out $@
+
+tzdata$(VERSION)-rearguard.tar.gz: rearguard.zi set-timestamps.out
+ rm -fr tzdata$(VERSION)-rearguard.dir
+ mkdir tzdata$(VERSION)-rearguard.dir
+ ln $(COMMON) $(DATA) $(MISC) tzdata$(VERSION)-rearguard.dir
+ cd tzdata$(VERSION)-rearguard.dir && \
+ rm -f $(TDATA) $(PACKRATDATA) version
+ for f in $(TDATA) $(PACKRATDATA); do \
+ rearf=tzdata$(VERSION)-rearguard.dir/$$f; \
+ $(AWK) -v DATAFORM=rearguard -f ziguard.awk $$f >$$rearf && \
+ touch -cmr `ls -t ziguard.awk $$f` $$rearf || exit; \
+ done
+ sed '1s/$$/-rearguard/' \
+ <version >tzdata$(VERSION)-rearguard.dir/version
+ touch -cmr version tzdata$(VERSION)-rearguard.dir/version
+ LC_ALL=C && export LC_ALL && \
+ (cd tzdata$(VERSION)-rearguard.dir && \
+ tar $(TARFLAGS) -cf - $(COMMON) $(DATA) $(MISC) | \
+ gzip $(GZIPFLAGS)) >$@.out
+ mv $@.out $@
+
+tzdb-$(VERSION).tar.lz: set-timestamps.out
+ rm -fr tzdb-$(VERSION)
+ mkdir tzdb-$(VERSION)
+ ln $(ENCHILADA) tzdb-$(VERSION)
+ touch -cmr `ls -t tzdb-$(VERSION)/* | sed 1q` tzdb-$(VERSION)
+ LC_ALL=C && export LC_ALL && \
+ tar $(TARFLAGS) -cf - tzdb-$(VERSION) | lzip -9 >$@.out
+ mv $@.out $@
+
+tzcode$(VERSION).tar.gz.asc: tzcode$(VERSION).tar.gz
+tzdata$(VERSION).tar.gz.asc: tzdata$(VERSION).tar.gz
+tzdata$(VERSION)-rearguard.tar.gz.asc: tzdata$(VERSION)-rearguard.tar.gz
+tzdb-$(VERSION).tar.lz.asc: tzdb-$(VERSION).tar.lz
+$(ALL_ASC):
+ gpg --armor --detach-sign $?
+
+typecheck:
+ $(MAKE) clean
+ for i in "long long" unsigned; \
+ do \
+ $(MAKE) CFLAGS="-DTYPECHECK -D__time_t_defined -D_TIME_T \"-Dtime_t=$$i\"" ; \
+ ./zdump -v Europe/Rome ; \
+ $(MAKE) clean ; \
+ done
+
+zonenames: tzdata.zi
+ @$(AWK) '/^Z/ { print $$2 } /^L/ { print $$3 }' tzdata.zi
+
+asctime.o: private.h tzfile.h
+date.o: private.h
+difftime.o: private.h
+localtime.o: private.h tzfile.h
+strftime.o: private.h tzfile.h
+zdump.o: version.h
+zic.o: private.h tzfile.h version.h
+
+.KEEP_STATE:
+
+.PHONY: ALL INSTALL all
+.PHONY: check check_character_set check_links check_name_lengths
+.PHONY: check_public check_sorted check_tables
+.PHONY: check_time_t_alternatives check_tzs check_web check_white_space
+.PHONY: check_zishrink
+.PHONY: clean clean_misc dummy.zd force_tzs
+.PHONY: install install_data maintainer-clean names
+.PHONY: posix_only posix_packrat posix_right
+.PHONY: public right_only right_posix signatures signatures_version
+.PHONY: tarballs tarballs_version
+.PHONY: traditional_signatures traditional_signatures_version
+.PHONY: traditional_tarballs traditional_tarballs_version
+.PHONY: typecheck
+.PHONY: zonenames zones
+.PHONY: $(ZDS)
diff --git a/NEWS b/NEWS
new file mode 100644
index 000000000000..9c445cd0be87
--- /dev/null
+++ b/NEWS
@@ -0,0 +1,4464 @@
+News for the tz database
+
+Release 2018e - 2018-05-01 23:42:51 -0700
+
+ Briefly:
+
+ North Korea switches back to +09 on 2018-05-05.
+ The main format uses negative DST again, for Ireland etc.
+ 'make tarballs' now also builds a rearguard tarball.
+ New 's' and 'd' suffixes in SAVE columns of Rule and Zone lines.
+
+ Changes to past and future time stamps
+
+ North Korea switches back from +0830 to +09 on 2018-05-05.
+ (Thanks to Kang Seonghoon, Arthur David Olson, Seo Sanghyeon,
+ and Tim Parenti.)
+
+ Bring back the negative-DST changes of 2018a, except be more
+ compatible with data parsers that do not support negative DST.
+ Also, this now affects historical time stamps in Namibia and the
+ former Czechoslovakia, not just Ireland. The main format now uses
+ negative DST to model time stamps in Europe/Dublin (from 1971 on),
+ Europe/Prague (1946/7), and Africa/Windhoek (1994/2017). This
+ does not affect UT offsets, only time zone abbreviations and the
+ tm_isdst flag. Also, this does not affect rearguard or vanguard
+ formats; effectively the main format now uses vanguard instead of
+ rearguard format. Data parsers that do not support negative DST
+ can still use data from the rearguard tarball described below.
+
+ Changes to build procedure
+
+ The command 'make tarballs' now also builds the tarball
+ tzdataVERSION-rearguard.tar.gz, which is like tzdataVERSION.tar.gz
+ except that it uses rearguard format intended for trailing-edge
+ data parsers.
+
+ Changes to data format and to code
+
+ The SAVE column of Rule and Zone lines can now have an 's' or 'd'
+ suffix, which specifies whether the adjusted time is standard time
+ or daylight saving time. If no suffix is given, daylight saving
+ time is used if and only if the SAVE column is nonzero; this is
+ the longstanding behavior. Although this new feature is not used
+ in tzdata, it could be used to specify the legal time in Namibia
+ 1994-2017, as opposed to the popular time (see below).
+
+ Changes to past time stamps
+
+ From 1994 through 2017 Namibia observed DST in winter, not summer.
+ That is, it used negative DST, as Ireland still does. This change
+ does not affect UTC offsets; it affects only the tm_isdst flag and
+ the abbreviation used during summer, which is now CAT, not WAST.
+ Although (as noted by Michael Deckers) summer and winter time were
+ both simply called "standard time" in Namibian law, in common
+ practice winter time was considered to be DST (as noted by Stephen
+ Colebourne). The full effect of this change is only in vanguard
+ format; in rearguard and main format, the tm_isdst flag is still
+ zero in winter and nonzero in summer.
+
+ In 1946/7 Czechoslovakia also observed negative DST in winter.
+ The full effect of this change is only in vanguard format; in
+ rearguard and main formats, it is modeled as plain GMT without
+ daylight saving. Also, the dates of some 1944/5 DST transitions
+ in Czechoslovakia have been changed.
+
+
+Release 2018d - 2018-03-22 07:05:46 -0700
+
+ Briefly:
+
+ Palestine starts DST a week earlier in 2018.
+ Add support for vanguard and rearguard data consumers.
+ Add subsecond precision to source data format, though not to data.
+
+ Changes to future time stamps
+
+ In 2018, Palestine starts DST on March 24, not March 31.
+ Adjust future predictions accordingly. (Thanks to Sharef Mustafa.)
+
+ Changes to past and future time stamps
+
+ Casey Station in Antarctica changed from +11 to +08 on 2018-03-11
+ at 04:00. (Thanks to Steffen Thorsen.)
+
+ Changes to past time stamps
+
+ Historical transitions for Uruguay, represented by
+ America/Montevideo, have been updated per official legal documents,
+ replacing previous data mainly originating from the inventions of
+ Shanks & Pottenger. This has resulted in adjustments ranging from
+ 30 to 90 minutes in either direction over at least two dozen
+ distinct periods ranging from one day to several years in length.
+ A mere handful of pre-1991 transitions are unaffected; data since
+ then has come from more reliable contemporaneous reporting. These
+ changes affect various timestamps in 1920-1923, 1936, 1939,
+ 1942-1943, 1959, 1966-1970, 1972, 1974-1980, and 1988-1990.
+ Additionally, Uruguay's pre-standard-time UT offset has been
+ adjusted westward by 7 seconds, from UT-03:44:44 to UT-03:44:51, to
+ match the location of the Observatory of the National Meteorological
+ Institute in Montevideo.
+ (Thanks to Jeremie Bonjour, Tim Parenti, and Michael Deckers.)
+
+ Enderbury and Kiritimati skipped New Year's Eve 1994, not
+ New Year's Day 1995. (Thanks to Kerry Shetline.)
+
+ Fix the 1912-01-01 transition for Portugal and its colonies.
+ This transition was at 00:00 according to the new UT offset, not
+ according to the old one. Also assume that Cape Verde switched on
+ the same date as the rest, not in 1907. This affects
+ Africa/Bissau, Africa/Sao_Tome, Asia/Macau, Atlantic/Azores,
+ Atlantic/Cape_Verde, Atlantic/Madeira, and Europe/Lisbon.
+ (Thanks to Michael Deckers.)
+
+ Fix an off-by-1 error for pre-1913 timestamps in Jamaica and in
+ Turks & Caicos.
+
+ Changes to past time zone abbreviations
+
+ MMT took effect in Uruguay from 1908-06-10, not 1898-06-28. There
+ is no clock change associated with the transition.
+
+ Changes to build procedure
+
+ The new DATAFORM macro in the Makefile lets the installer choose
+ among three source data formats. The idea is to lessen downstream
+ disruption when data formats are improved.
+
+ * DATAFORM=vanguard installs from the latest, bleeding-edge
+ format. DATAFORM=main (the default) installs from the format
+ used in the 'africa' etc. files. DATAFORM=rearguard installs
+ from a trailing-edge format. Eventually, elements of today's
+ vanguard format should move to the main format, and similarly
+ the main format's features should eventually move to the
+ rearguard format.
+
+ * In the current version, the main and rearguard formats are
+ identical and match that of 2018c, so this change does not
+ affect default behavior. The vanguard format currently contains
+ one feature not in the main format: negative SAVE values. This
+ improves support for Ireland, which uses Irish Standard Time
+ (IST, UTC+01) in summer and GMT (UTC) in winter. tzcode has
+ supported negative SAVE values for decades, and this feature
+ should move to the main format soon. However, it will not move
+ to the rearguard format for quite some time because some
+ downstream parsers do not support it.
+
+ * The build procedure constructs three files vanguard.zi, main.zi,
+ and rearguard.zi, one for each format. The files represent the
+ same data as closely as the formats allow. These three files
+ are intended for downstream data consumers and are not
+ installed. Zoneinfo parsers that do not support negative SAVE values
+ should start using rearguard.zi, so that they will be unaffected
+ when the negative-DST feature moves from vanguard to main.
+ Bleeding-edge Zoneinfo parsers that support the new features
+ already can use vanguard.zi; in this respect, current tzcode is
+ bleeding-edge.
+
+ The Makefile should now be safe for parallelized builds, and 'make
+ -j to2050new.tzs' is now much faster on a multiprocessor host
+ with GNU Make.
+
+ When built with -DSUPPRESS_TZDIR, the tzcode library no longer
+ prepends TZDIR/ to file names that do not begin with '/'. This is
+ not recommended for general use, due to its security implications.
+ (From a suggestion by Manuela Friedrich.)
+
+ Changes to code
+
+ zic now accepts subsecond precision in expressions like
+ 00:19:32.13, which is approximately the legal time of the
+ Netherlands from 1835 to 1937. However, because it is
+ questionable whether the few recorded uses of non-integer offsets
+ had subsecond precision in practice, there are no plans for tzdata
+ to use this feature. (Thanks to Steve Allen for pointing out
+ the limitations of historical data in this area.)
+
+ The code is a bit more portable to MS-Windows. Installers can
+ compile with -DRESERVE_STD_EXT_IDS on MS-Windows platforms that
+ reserve identifiers like 'localtime'. (Thanks to Manuela
+ Friedrich).
+
+ Changes to documentation and commentary
+
+ theory.html now outlines tzdb's extensions to POSIX's model for
+ civil time, and has a section "POSIX features no longer needed"
+ that lists POSIX API components that are now vestigial.
+ (From suggestions by Steve Summit.) It also better distinguishes
+ time zones from tz regions. (From a suggestion by Guy Harris.)
+
+ Commentary is now more consistent about using the phrase "daylight
+ saving time", to match the C name tm_isdst. Daylight saving time
+ need not occur in summer, and need not have a positive offset from
+ standard time.
+
+ Commentary about historical transitions in Uruguay has been expanded
+ with links to many relevant legal documents.
+ (Thanks to Tim Parenti.)
+
+ Commentary now uses some non-ASCII characters with Unicode value
+ less than U+0100, as they can be useful and should work even with
+ older editors such as XEmacs.
+
+
+Release 2018c - 2018-01-22 23:00:44 -0800
+
+ Briefly:
+ Revert Irish changes that relied on negative SAVE values.
+
+ Changes to tm_isdst
+
+ Revert the 2018a change to Europe/Dublin. As before, this change
+ does not affect UT offsets or abbreviations; it affects only
+ whether timestamps are considered to be standard time or
+ daylight-saving time, as expressed in the tm_isdst flag of C's
+ struct tm type. This reversion is intended to be a temporary
+ workaround for problems discovered with downstream uses of
+ releases 2018a and 2018b, which implemented Irish time by using
+ negative SAVE values in the Eire rules of the 'europe' file.
+ Although negative SAVE values have been part of tzcode for many
+ years and are supported by many platforms, they were not
+ documented before 2018a and ICU and OpenJDK do not currently
+ support them. A mechanism to export data to platforms lacking
+ support for negative DST is planned to be developed before the
+ change is reapplied. (Problems reported by Deborah Goldsmith and
+ Stephen Colebourne.)
+
+ Changes to past time stamps
+
+ Japanese DST transitions (1948-1951) were Sundays at 00:00, not
+ Saturdays or Sundays at 02:00. (Thanks to Takayuki Nikai.)
+
+ Changes to build procedure
+
+ The build procedure now works around mawk 1.3.3's lack of support
+ for character class expressions. (Problem reported by Ohyama.)
+
+
+Release 2018b - 2018-01-17 23:24:48 -0800
+
+ Briefly:
+ Fix a packaging problem in tz2018a, which was missing 'pacificnew'.
+
+ Changes to build procedure
+
+ The distribution now contains the file 'pacificnew' again.
+ This file was inadvertantly omitted in the 2018a distribution.
+ (Problem reported by Matias Fonzo.)
+
+
+Release 2018a - 2018-01-12 22:29:21 -0800
+
+ Briefly:
+ São Tomé and Príncipe switched from +00 to +01.
+ Brazil's DST will now start on November's first Sunday.
+ Ireland's standard time is now in the summer, not the winter.
+ Use Debian-style installation locations, instead of 4.3BSD-style.
+ New zic option -t.
+
+ Changes to past and future time stamps
+
+ São Tomé and Príncipe switched from +00 to +01 on 2018-01-01 at
+ 01:00. (Thanks to Steffen Thorsen and Michael Deckers.)
+
+ Changes to future time stamps
+
+ Starting in 2018 southern Brazil will begin DST on November's
+ first Sunday instead of October's third Sunday. (Thanks to
+ Steffen Thorsen.)
+
+ Changes to past time stamps
+
+ A discrepancy of 4 s in timestamps before 1931 in South Sudan has
+ been corrected. The 'backzone' and 'zone.tab' files did not agree
+ with the 'africa' and 'zone1970.tab' files. (Problem reported by
+ Michael Deckers.)
+
+ The abbreviation invented for Bolivia Summer Time (1931-2) is now
+ BST instead of BOST, to be more consistent with the convention
+ used for Latvian Summer Time (1918-9) and for British Summer Time.
+
+ Changes to tm_isdst
+
+ Change Europe/Dublin so that it observes Irish Standard Time (UT
+ +01) in summer and GMT (as negative daylight-saving) in winter,
+ instead of observing standard time (GMT) in winter and Irish
+ Summer Time (UT +01) in summer. This change does not affect UT
+ offsets or abbreviations; it affects only whether timestamps are
+ considered to be standard time or daylight-saving time, as
+ expressed in the tm_isdst flag of C's struct tm type.
+ (Discrepancy noted by Derick Rethans.)
+
+ Changes to build procedure
+
+ The default installation locations have been changed to mostly
+ match Debian circa 2017, instead of being designed as an add-on to
+ 4.3BSD circa 1986. This affects the Makefile macros TOPDIR,
+ TZDIR, MANDIR, and LIBDIR. New Makefile macros TZDEFAULT, USRDIR,
+ USRSHAREDIR, BINDIR, ZDUMPDIR, and ZICDIR let installers tailor
+ locations more precisely. (This responds to suggestions from
+ Brian Inglis and from Steve Summit.)
+
+ The default installation procedure no longer creates the
+ backward-compatibility link US/Pacific-New, which causes
+ confusion during user setup (e.g., see Debian bug 815200).
+ Use 'make BACKWARD="backward pacificnew"' to create the link
+ anyway, for now. Eventually we plan to remove the link entirely.
+
+ tzdata.zi now contains a version-number comment.
+ (Suggested by Tom Lane.)
+
+ The Makefile now quotes values like BACKWARD more carefully when
+ passing them to the shell. (Problem reported by Zefram.)
+
+ Builders no longer need to specify -DHAVE_SNPRINTF on platforms
+ that have snprintf and use pre-C99 compilers. (Problem reported
+ by Jon Skeet.)
+
+ Changes to code
+
+ zic has a new option -t FILE that specifies the location of the
+ file that determines local time when TZ is unset. The default for
+ this location can be configured via the new TZDEFAULT makefile
+ macro, which defaults to /etc/localtime.
+
+ Diagnostics and commentary now distinguish UT from UTC more
+ carefully; see theory.html for more information about UT vs UTC.
+
+ zic has been ported to GCC 8's -Wstringop-truncation option.
+ (Problem reported by Martin Sebor.)
+
+ Changes to documentation and commentary
+
+ The zic man page now documents the longstanding behavior that
+ times and years can be out of the usual range, with negative times
+ counting backwards from midnight and with year 0 preceding year 1.
+ (Problem reported by Michael Deckers.)
+
+ The theory.html file now mentions the POSIX limit of six chars
+ per abbreviation, and lists alphabetic abbreviations used.
+
+ The files tz-art.htm and tz-link.htm have been renamed to
+ tz-art.html and tz-link.html, respectively, for consistency with
+ other file names and to simplify web server configuration.
+
+
+Release 2017c - 2017-10-20 14:49:34 -0700
+
+ Briefly:
+ Northern Cyprus switches from +03 to +02/+03 on 2017-10-29.
+ Fiji ends DST 2018-01-14, not 2018-01-21.
+ Namibia switches from +01/+02 to +02 on 2018-04-01.
+ Sudan switches from +03 to +02 on 2017-11-01.
+ Tonga likely switches from +13/+14 to +13 on 2017-11-05.
+ Turks & Caicos switches from -04 to -05/-04 on 2018-11-04.
+ A new file tzdata.zi now holds a small text copy of all data.
+ The zic input format has been regularized slightly.
+
+ Changes to future time stamps
+
+ Northern Cyprus has decided to resume EU rules starting
+ 2017-10-29, thus reinstituting winter time.
+
+ Fiji ends DST 2018-01-14 instead of the 2018-01-21 previously
+ predicted. (Thanks to Dominic Fok.) Adjust future predictions
+ accordingly.
+
+ Namibia will switch from +01 with DST to +02 all year on
+ 2017-09-03 at 02:00. This affects UT offsets starting 2018-04-01
+ at 02:00. (Thanks to Steffen Thorsen.)
+
+ Sudan will switch from +03 to +02 on 2017-11-01. (Thanks to Ahmed
+ Atyya and Yahia Abdalla.) South Sudan is not switching, so
+ Africa/Juba is no longer a link to Africa/Khartoum.
+
+ Tonga has likely ended its experiment with DST, and will not
+ adjust its clocks on 2017-11-05. Although Tonga has not announced
+ whether it will continue to observe DST, the IATA is assuming that
+ it will not. (Thanks to David Wade.)
+
+ Turks & Caicos will switch from -04 all year to -05 with US DST on
+ 2018-03-11 at 03:00. This affects UT offsets starting 2018-11-04
+ at 02:00. (Thanks to Steffen Thorsen.)
+
+ Changes to past time stamps
+
+ Namibia switched from +02 to +01 on 1994-03-21, not 1994-04-03.
+ (Thanks to Arthur David Olson.)
+
+ Detroit did not observe DST in 1967.
+
+ Use railway time for Asia/Kolkata before 1941, by switching to
+ Madras local time (UT +052110) in 1870, then to IST (UT +0530) in
+ 1906. Also, treat 1941-2's +0630 as DST, like 1942-5.
+
+ Europe/Dublin's 1946 and 1947 fallback transitions occurred at
+ 02:00 standard time, not 02:00 DST. (Thanks to Michael Deckers.)
+
+ Pacific/Apia and Pacific/Pago_Pago switched from Antipodean to
+ American time in 1892, not 1879. (Thanks to Michael Deckers.)
+
+ Adjust the 1867 transition in Alaska to better reflect the
+ historical record, by changing it to occur on 1867-10-18 at 15:30
+ Sitka time rather than at the start of 1867-10-17 local time.
+ Although strictly speaking this is accurate only for Sitka,
+ the rest of Alaska's blanks need to be filled in somehow.
+
+ Fix off-by-one errors in UT offsets for Adak and Nome before 1867.
+ (Thanks to Michael Deckers.)
+
+ Add 7 s to the UT offset in Asia/Yangon before 1920.
+
+ Changes to zone names
+
+ Remove Canada/East-Saskatchewan from the 'backward' file, as it
+ exceeded the 14-character limit and was an unused misnomer anyway.
+
+ Changes to build procedure
+
+ To support applications that prefer to read time zone data in text
+ form, two zic input files tzdata.zi and leapseconds are now
+ installed by default. The commands 'zic tzdata.zi' and 'zic -L
+ leapseconds tzdata.zi' can reproduce the tzdata binary files
+ without and with leap seconds, respectively. To prevent these two
+ new files from being installed, use 'make TZDATA_TEXT=', and to
+ suppress leap seconds from the tzdata text installation, use 'make
+ TZDATA_TEXT=tzdata.zi'.
+
+ 'make BACKWARD=' now suppresses backward-compatibility names
+ like 'US/Pacific' that are defined in the 'backward' and
+ 'pacificnew' files.
+
+ 'make check' now works on systems that lack a UTF-8 locale,
+ or that lack the nsgmls program. Set UTF8_LOCALE to configure
+ the name of a UTF-8 locale, if you have one.
+
+ Y2K runtime checks are no longer enabled by default. Add
+ -DDEPRECATE_TWO_DIGIT_YEARS to CFLAGS to enable them, instead of
+ adding -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
+ to disable them. (New name suggested by Brian Inglis.)
+
+ The build procedure for zdump now works on AIX 7.1.
+ (Problem reported by Kees Dekker.)
+
+ Changes to code
+
+ zic and the reference runtime now reject multiple leap seconds
+ within 28 days of each other, or leap seconds before the Epoch.
+ As a result, support for double leap seconds, which was
+ obsolescent and undocumented, has been removed. Double leap
+ seconds were an error in the C89 standard; they have never existed
+ in civil timekeeping. (Thanks to Robert Elz and Bradley White for
+ noticing glitches in the code that uncovered this problem.)
+
+ zic now warns about use of the obsolescent and undocumented -y
+ option, and about use of the obsolescent TYPE field of Rule lines.
+
+ zic now allows unambiguous abbreviations like "Sa" and "Su" for
+ weekdays; formerly it rejected them due to a bug. Conversely, zic
+ no longer considers non-prefixes to be abbreviations; for example,
+ it no longer accepts "lF" as an abbreviation for "lastFriday".
+ Also, zic warns about the undocumented usage with a "last-"
+ prefix, e.g., "last-Fri".
+
+ Similarly, zic now accepts the unambiguous abbreviation "L" for
+ "Link" in ordinary context and for "Leap" in leap-second context.
+ Conversely, zic no longer accepts non-prefixes such as "La" as
+ abbreviations for words like "Leap".
+
+ zic no longer accepts leap second lines in ordinary input, or
+ ordinary lines in leap second input. Formerly, zic sometimes
+ warned about this undocumented usage and handled it incorrectly.
+
+ The new macro HAVE_TZNAME governs whether the tzname external
+ variable is exported, instead of USG_COMPAT. USG_COMPAT now
+ governs only the external variables "timezone" and "daylight".
+ This change is needed because the three variables are not in the
+ same category: although POSIX requires tzname, it specifies the
+ other two variables as optional. Also, USG_COMPAT is now 1 or 0:
+ if not defined, the code attempts to guess it from other macros.
+
+ localtime.c and difftime.c no longer require stdio.h, and .c files
+ other than zic.c no longer require sys/wait.h.
+
+ zdump.c no longer assumes snprintf. (Reported by Jonathan Leffler.)
+
+ Calculation of time_t extrema works around a bug in GCC 4.8.4
+ (Reported by Stan Shebs and Joseph Myers.)
+
+ zic.c no longer mistranslates formats of line numbers in non-English
+ locales. (Problem reported by Benno Schulenberg.)
+
+ Several minor changes have been made to the code to make it a
+ bit easier to port to MS-Windows and Solaris. (Thanks to Kees
+ Dekker for reporting the problems.)
+
+ Changes to documentation and commentary
+
+ The two new files 'theory.html' and 'calendars' contain the
+ contents of the removed file 'Theory'. The goal is to document
+ tzdb theory more accessibly.
+
+ The zic man page now documents abbreviation rules.
+
+ tz-link.htm now covers how to apply tzdata changes to clients.
+ (Thanks to Jorge Fábregas for the AIX link.) It also mentions MySQL.
+
+ The leap-seconds.list URL has been updated to something that is
+ more reliable for tzdb. (Thanks to Tim Parenti and Brian Inglis.)
+
+Release 2017b - 2017-03-17 07:30:38 -0700
+
+ Briefly: Haiti has resumed DST.
+
+ Changes to past and future time stamps
+
+ Haiti resumed observance of DST in 2017. (Thanks to Steffen Thorsen.)
+
+ Changes to past time stamps
+
+ Liberia changed from -004430 to +00 on 1972-01-07, not 1972-05-01.
+
+ Use "MMT" to abbreviate Liberia's time zone before 1972, as "-004430"
+ is one byte over the POSIX limit. (Problem reported by Derick Rethans.)
+
+ Changes to code
+
+ The reference localtime implementation now falls back on the
+ current US daylight-saving transition rules rather than the
+ 1987-2006 rules. This fallback occurs only when (1) the TZ
+ environment variable's value has a name like "AST4ADT" that asks
+ for daylight saving time but does not specify the rules, (2) there
+ is no file by that name, and (3) the TZDEFRULES file cannot be
+ loaded. (Thanks to Tom Lane.)
+
+
+Release 2017a - 2017-02-28 00:05:36 -0800
+
+ Briefly: Southern Chile moves from -04/-03 to -03, and Mongolia
+ discontinues DST.
+
+ Changes to future time stamps
+
+ Mongolia no longer observes DST. (Thanks to Ganbold Tsagaankhuu.)
+
+ Chile's Region of Magallanes moves from -04/-03 to -03 year-round.
+ Its clocks diverge from America/Santiago starting 2017-05-13 at
+ 23:00, hiving off a new zone America/Punta_Arenas. Although the
+ Chilean government says this change expires in May 2019, for now
+ assume it's permanent. (Thanks to Juan Correa and Deborah
+ Goldsmith.) This also affects Antarctica/Palmer.
+
+ Changes to past time stamps
+
+ Fix many entries for historical time stamps for Europe/Madrid
+ before 1979, to agree with tables compiled by Pere Planesas of the
+ National Astronomical Observatory of Spain. As a side effect,
+ this changes some time stamps for Africa/Ceuta before 1929, which
+ are probably guesswork anyway. (Thanks to Steve Allen and
+ Pierpaolo Bernardi for the heads-ups, and to Michael Deckers for
+ correcting the 1901 transition.)
+
+ Ecuador observed DST from 1992-11-28 to 1993-02-05.
+ (Thanks to Alois Treindl.)
+
+ Asia/Atyrau and Asia/Oral were at +03 (not +04) before 1930-06-21.
+ (Thanks to Stepan Golosunov.)
+
+ Changes to past and future time zone abbreviations
+
+ Switch to numeric time zone abbreviations for South America, as
+ part of the ongoing project of removing invented abbreviations.
+ This avoids the need to invent an abbreviation for the new Chilean
+ new zone. Similarly, switch from invented to numeric time zone
+ abbreviations for Afghanistan, American Samoa, the Azores,
+ Bangladesh, Bhutan, the British Indian Ocean Territory, Brunei,
+ Cape Verde, Chatham Is, Christmas I, Cocos (Keeling) Is, Cook Is,
+ Dubai, East Timor, Eucla, Fiji, French Polynesia, Greenland,
+ Indochina, Iran, Iraq, Kiribati, Lord Howe, Macquarie, Malaysia,
+ the Maldives, Marshall Is, Mauritius, Micronesia, Mongolia,
+ Myanmar, Nauru, Nepal, New Caledonia, Niue, Norfolk I, Palau,
+ Papua New Guinea, the Philippines, Pitcairn, Qatar, Réunion, St
+ Pierre & Miquelon, Samoa, Saudi Arabia, Seychelles, Singapore,
+ Solomon Is, Tokelau, Tuvalu, Wake, Vanuatu, Wallis & Futuna, and
+ Xinjiang; for 20-minute daylight saving time in Ghana before 1943;
+ for half-hour daylight saving time in Belize before 1944 and in
+ the Dominican Republic before 1975; and for Canary Islands before
+ 1946, for Guinea-Bissau before 1975, for Iceland before 1969, for
+ Indian Summer Time before 1942, for Indonesia before around 1964,
+ for Kenya before 1960, for Liberia before 1973, for Madeira before
+ 1967, for Namibia before 1943, for the Netherlands in 1937-9, for
+ Pakistan before 1971, for Western Sahara before 1977, and for
+ Zaporozhye in 1880-1924.
+
+ For Alaska time from 1900 through 1967, instead of "CAT" use the
+ abbreviation "AST", the abbreviation commonly used at the time
+ (Atlantic Standard Time had not been standardized yet). Use "AWT"
+ and "APT" instead of the invented abbreviations "CAWT" and "CAPT".
+
+ Use "CST" and "CDT" instead of invented abbreviations for Macau
+ before 1999 and Taiwan before 1938, and use "JST" instead of the
+ invented abbreviation "JCST" for Japan and Korea before 1938.
+
+ Change to database entry category
+
+ Move the Pacific/Johnston link from 'australasia' to 'backward',
+ since Johnston is now uninhabited.
+
+ Changes to code
+
+ zic no longer mishandles some transitions in January 2038 when it
+ attempts to work around Qt bug 53071. This fixes a bug affecting
+ Pacific/Tongatapu that was introduced in zic 2016e. localtime.c
+ now contains a workaround, useful when loading a file generated by
+ a buggy zic. (Problem and localtime.c fix reported by Bradley
+ White.)
+
+ zdump -i now outputs non-hour numeric time zone abbreviations
+ without a colon, e.g., "+0530" rather than "+05:30". This agrees
+ with zic %z and with common practice, and simplifies auditing of
+ zdump output.
+
+ zdump is now buildable again with -DUSE_LTZ=0.
+ (Problem reported by Joseph Myers.)
+
+ zdump.c now always includes private.h, to avoid code duplication
+ with private.h. (Problem reported by Kees Dekker.)
+
+ localtime.c no longer mishandles early or late timestamps
+ when TZ is set to a POSIX-style string that specifies DST.
+ (Problem reported by Kees Dekker.)
+
+ date and strftime now cause %z to generate "-0000" instead of
+ "+0000" when the UT offset is zero and the time zone abbreviation
+ begins with "-".
+
+ Changes to documentation and commentary
+
+ The 'Theory' file now better documents choice of historical time
+ zone abbreviations. (Problems reported by Michael Deckers.)
+
+ tz-link.htm now covers leap smearing, which is popular in clouds.
+
+
+Release 2016j - 2016-11-22 23:17:13 -0800
+
+ Briefly: Saratov, Russia moves from +03 to +04 on 2016-12-04.
+
+ Changes to future time stamps
+
+ Saratov, Russia switches from +03 to +04 on 2016-12-04 at 02:00.
+ This hives off a new zone Europe/Saratov from Europe/Volgograd.
+ (Thanks to Yuri Konotopov and Stepan Golosunov.)
+
+ Changes to past time stamps
+
+ The new zone Asia/Atyrau for Atyraū Region, Kazakhstan, is like
+ Asia/Aqtau except it switched from +05/+06 to +04/+05 in spring
+ 1999, not fall 1994. (Thanks to Stepan Golosunov.)
+
+ Changes to past time zone abbreviations
+
+ Asia/Gaza and Asia/Hebron now use "EEST", not "EET", to denote
+ summer time before 1948. The old use of "EET" was a typo.
+
+ Changes to code
+
+ zic no longer mishandles file systems that lack hard links, fixing
+ bugs introduced in 2016g. (Problems reported by Tom Lane.)
+ Also, when the destination already contains symbolic links, zic
+ should now work better on systems where the 'link' system call
+ does not follow symbolic links.
+
+ Changes to documentation and commentary
+
+ tz-link.htm now documents the relationship between release version
+ numbers and development-repository commit tags. (Suggested by
+ Paul Koning.)
+
+ The 'Theory' file now documents UT.
+
+ iso3166.tab now accents "Curaçao", and commentary now mentions
+ the names "Cabo Verde" and "Czechia". (Thanks to Jiří Boháč.)
+
+
+Release 2016i - 2016-11-01 23:19:52 -0700
+
+ Briefly: Cyprus split into two time zones on 2016-10-30, and Tonga
+ reintroduces DST on 2016-11-06.
+
+ Changes to future time stamps
+
+ Pacific/Tongatapu begins DST on 2016-11-06 at 02:00, ending on
+ 2017-01-15 at 03:00. Assume future observances in Tonga will be
+ from the first Sunday in November through the third Sunday in
+ January, like Fiji. (Thanks to Pulu ʻAnau.) Switch to numeric
+ time zone abbreviations for this zone.
+
+ Changes to past and future time stamps
+
+ Northern Cyprus is now +03 year round, causing a split in Cyprus
+ time zones starting 2016-10-30 at 04:00. This creates a zone
+ Asia/Famagusta. (Thanks to Even Scharning and Matt Johnson.)
+
+ Antarctica/Casey switched from +08 to +11 on 2016-10-22.
+ (Thanks to Steffen Thorsen.)
+
+ Changes to past time stamps
+
+ Several corrections were made for pre-1975 time stamps in Italy.
+ These affect Europe/Malta, Europe/Rome, Europe/San_Marino, and
+ Europe/Vatican.
+
+ First, the 1893-11-01 00:00 transition in Italy used the new UT
+ offset (+01), not the old (+00:49:56). (Thanks to Michael
+ Deckers.)
+
+ Second, rules for daylight saving in Italy were changed to agree
+ with Italy's National Institute of Metrological Research (INRiM)
+ except for 1944, as follows (thanks to Pierpaolo Bernardi, Brian
+ Inglis, and Michael Deckers):
+
+ The 1916-06-03 transition was at 24:00, not 00:00.
+
+ The 1916-10-01, 1919-10-05, and 1920-09-19 transitions were at
+ 00:00, not 01:00.
+
+ The 1917-09-30 and 1918-10-06 transitions were at 24:00, not
+ 01:00.
+
+ The 1944-09-17 transition was at 03:00, not 01:00. This
+ particular change is taken from Italian law as INRiM's table,
+ (which says 02:00) appears to have a typo here. Also, keep the
+ 1944-04-03 transition for Europe/Rome, as Rome was controlled by
+ Germany then.
+
+ The 1967-1970 and 1972-1974 fallback transitions were at 01:00,
+ not 00:00.
+
+ Changes to code
+
+ The code should now be buildable on AmigaOS merely by setting the
+ appropriate Makefile variables. (From a patch by Carsten Larsen.)
+
+
+Release 2016h - 2016-10-19 23:17:57 -0700
+
+ Changes to future time stamps
+
+ Asia/Gaza and Asia/Hebron end DST on 2016-10-29 at 01:00, not
+ 2016-10-21 at 00:00. (Thanks to Sharef Mustafa.) Predict that
+ future fall transitions will be on the last Saturday of October
+ at 01:00, which is consistent with predicted spring transitions
+ on the last Saturday of March. (Thanks to Tim Parenti.)
+
+ Changes to past time stamps
+
+ In Turkey, transitions in 1986-1990 were at 01:00 standard time
+ not at 02:00, and the spring 1994 transition was on March 20, not
+ March 27. (Thanks to Kıvanç Yazan.)
+
+ Changes to past and future time zone abbreviations
+
+ Asia/Colombo now uses numeric time zone abbreviations like "+0530"
+ instead of alphabetic ones like "IST" and "LKT". Various
+ English-language sources use "IST", "LKT" and "SLST", with no
+ working consensus. (Usage of "SLST" mentioned by Sadika
+ Sumanapala.)
+
+ Changes to code
+
+ zic no longer mishandles relativizing file names when creating
+ symbolic links like /etc/localtime, when these symbolic links
+ are outside the usual directory hierarchy. This fixes a bug
+ introduced in 2016g. (Problem reported by Andreas Stieger.)
+
+ Changes to build procedure
+
+ New rules 'traditional_tarballs' and 'traditional_signatures' for
+ building just the traditional-format distribution. (Requested by
+ Deborah Goldsmith.)
+
+ The file 'version' is now put into the tzdata tarball too.
+ (Requested by Howard Hinnant.)
+
+ Changes to documentation and commentary
+
+ The 'Theory' file now has a section on interface stability.
+ (Requested by Paul Koning.) It also mentions features like
+ tm_zone and localtime_rz that have long been supported by the
+ reference code.
+
+ tz-link.htm has improved coverage of time zone boundaries suitable
+ for geolocation. (Thanks to heads-ups from Evan Siroky and Matt
+ Johnson.)
+
+ The US commentary now mentions Allen and the "day of two noons".
+
+ The Fiji commentary mentions the government's 2016-10-03 press
+ release. (Thanks to Raymond Kumar.)
+
+
+Release 2016g - 2016-09-13 08:56:38 -0700
+
+ Changes to future time stamps
+
+ Turkey switched from EET/EEST (+02/+03) to permanent +03,
+ effective 2016-09-07. (Thanks to Burak AYDIN.) Use "+03" rather
+ than an invented abbreviation for the new time.
+
+ New leap second 2016-12-31 23:59:60 UTC as per IERS Bulletin C 52.
+ (Thanks to Tim Parenti.)
+
+ Changes to past time stamps
+
+ For America/Los_Angeles, spring-forward transition times have been
+ corrected from 02:00 to 02:01 in 1948, and from 02:00 to 01:00 in
+ 1950-1966.
+
+ For zones using Soviet time on 1919-07-01, transitions to UT-based
+ time were at 00:00 UT, not at 02:00 local time. The affected
+ zones are Europe/Kirov, Europe/Moscow, Europe/Samara, and
+ Europe/Ulyanovsk. (Thanks to Alexander Belopolsky.)
+
+ Changes to past and future time zone abbreviations
+
+ The Factory zone now uses the time zone abbreviation -00 instead
+ of a long English-language string, as -00 is now the normal way to
+ represent an undefined time zone.
+
+ Several zones in Antarctica and the former Soviet Union, along
+ with zones intended for ships at sea that cannot use POSIX TZ
+ strings, now use numeric time zone abbreviations instead of
+ invented or obsolete alphanumeric abbreviations. The affected
+ zones are Antarctica/Casey, Antarctica/Davis,
+ Antarctica/DumontDUrville, Antarctica/Mawson, Antarctica/Rothera,
+ Antarctica/Syowa, Antarctica/Troll, Antarctica/Vostok,
+ Asia/Anadyr, Asia/Ashgabat, Asia/Baku, Asia/Bishkek, Asia/Chita,
+ Asia/Dushanbe, Asia/Irkutsk, Asia/Kamchatka, Asia/Khandyga,
+ Asia/Krasnoyarsk, Asia/Magadan, Asia/Omsk, Asia/Sakhalin,
+ Asia/Samarkand, Asia/Srednekolymsk, Asia/Tashkent, Asia/Tbilisi,
+ Asia/Ust-Nera, Asia/Vladivostok, Asia/Yakutsk, Asia/Yekaterinburg,
+ Asia/Yerevan, Etc/GMT-14, Etc/GMT-13, Etc/GMT-12, Etc/GMT-11,
+ Etc/GMT-10, Etc/GMT-9, Etc/GMT-8, Etc/GMT-7, Etc/GMT-6, Etc/GMT-5,
+ Etc/GMT-4, Etc/GMT-3, Etc/GMT-2, Etc/GMT-1, Etc/GMT+1, Etc/GMT+2,
+ Etc/GMT+3, Etc/GMT+4, Etc/GMT+5, Etc/GMT+6, Etc/GMT+7, Etc/GMT+8,
+ Etc/GMT+9, Etc/GMT+10, Etc/GMT+11, Etc/GMT+12, Europe/Kaliningrad,
+ Europe/Minsk, Europe/Samara, Europe/Volgograd, and
+ Indian/Kerguelen. For Europe/Moscow the invented abbreviation MSM
+ was replaced by +05, whereas MSK and MSD were kept as they are not
+ our invention and are widely used.
+
+ Changes to zone names
+
+ Rename Asia/Rangoon to Asia/Yangon, with a backward compatibility link.
+ (Thanks to David Massoud.)
+
+ Changes to code
+
+ zic no longer generates binary files containing POSIX TZ-like
+ strings that disagree with the local time type after the last
+ explicit transition in the data. This fixes a bug with
+ Africa/Casablanca and Africa/El_Aaiun in some year-2037 time
+ stamps on the reference platform. (Thanks to Alexander Belopolsky
+ for reporting the bug and suggesting a way forward.)
+
+ If the installed localtime and/or posixrules files are symbolic
+ links, zic now keeps them symbolic links when updating them, for
+ compatibility with platforms like OpenSUSE where other programs
+ configure these files as symlinks.
+
+ zic now avoids hard linking to symbolic links, avoids some
+ unnecessary mkdir and stat system calls, and uses shorter file
+ names internally.
+
+ zdump has a new -i option to generate transitions in a
+ more-compact but still human-readable format. This option is
+ experimental, and the output format may change in future versions.
+ (Thanks to Jon Skeet for suggesting that an option was needed,
+ and thanks to Tim Parenti and Chris Rovick for further comments.)
+
+ Changes to build procedure
+
+ An experimental distribution format is available, in addition
+ to the traditional format which will continue to be distributed.
+ The new format is a tarball tzdb-VERSION.tar.lz with signature
+ file tzdb-VERSION.tar.lz.asc. It unpacks to a top-level directory
+ tzdb-VERSION containing the code and data of the traditional
+ two-tarball format, along with extra data that may be useful.
+ (Thanks to Antonio Diaz Diaz, Oscar van Vlijmen, and many others
+ for comments about the experimental format.)
+
+ The release version number is now more accurate in the usual case
+ where releases are built from a Git repository. For example, if
+ 23 commits and some working-file changes have been made since
+ release 2016g, the version number is now something like
+ '2016g-23-g50556e3-dirty' instead of the misleading '2016g'.
+ Tagged releases use the same version number format as before,
+ e.g., '2016g'. To support the more-accurate version number, its
+ specification has moved from a line in the Makefile to a new
+ source file 'version'.
+
+ The experimental distribution contains a file to2050.tzs that
+ contains what should be the output of 'zdump -i -c 2050' on
+ primary zones. If this file is available, 'make check' now checks
+ that zdump generates this output.
+
+ 'make check_web' now works on Fedora-like distributions.
+
+ Changes to documentation and commentary
+
+ tzfile.5 now documents the new restriction on POSIX TZ-like
+ strings that is now implemented by zic.
+
+ Comments now cite URLs for some 1917-1921 Russian DST decrees.
+ (Thanks to Alexander Belopolsky.)
+
+ tz-link.htm mentions JuliaTime (thanks to Curtis Vogt) and Time4J
+ (thanks to Meno Hochschild) and ThreeTen-Extra, and its
+ description of Java 8 has been brought up to date (thanks to
+ Stephen Colebourne). Its description of local time on Mars has
+ been updated to match current practice, and URLs have been updated
+ and some obsolete ones removed.
+
+
+Release 2016f - 2016-07-05 16:26:51 +0200
+
+ Changes affecting future time stamps
+
+ The Egyptian government changed its mind on short notice, and
+ Africa/Cairo will not introduce DST starting 2016-07-07 after all.
+ (Thanks to Mina Samuel.)
+
+ Asia/Novosibirsk switches from +06 to +07 on 2016-07-24 at 02:00.
+ (Thanks to Stepan Golosunov.)
+
+ Changes to past and future time stamps
+
+ Asia/Novokuznetsk and Asia/Novosibirsk now use numeric time zone
+ abbreviations instead of invented ones.
+
+ Changes affecting past time stamps
+
+ Europe/Minsk's 1992-03-29 spring-forward transition was at 02:00 not 00:00.
+ (Thanks to Stepan Golosunov.)
+
+
+Release 2016e - 2016-06-14 08:46:16 -0700
+
+ Changes affecting future time stamps
+
+ Africa/Cairo observes DST in 2016 from July 7 to the end of October.
+ Guess October 27 and 24:00 transitions. (Thanks to Steffen Thorsen.)
+ For future years, guess April's last Thursday to October's last
+ Thursday except for Ramadan.
+
+ Changes affecting past time stamps
+
+ Locations while uninhabited now use '-00', not 'zzz', as a
+ placeholder time zone abbreviation. This is inspired by Internet
+ RFC 3339 and is more consistent with numeric time zone
+ abbreviations already used elsewhere. The change affects several
+ arctic and antarctic locations, e.g., America/Cambridge_Bay before
+ 1920 and Antarctica/Troll before 2005.
+
+ Asia/Baku's 1992-09-27 transition from +04 (DST) to +04 (non-DST) was
+ at 03:00, not 23:00 the previous day. (Thanks to Michael Deckers.)
+
+ Changes to code
+
+ zic now outputs a dummy transition at time 2**31 - 1 in zones
+ whose POSIX-style TZ strings contain a '<'. This mostly works
+ around Qt bug 53071 <https://bugreports.qt.io/browse/QTBUG-53071>.
+ (Thanks to Zhanibek Adilbekov for reporting the Qt bug.)
+
+ Changes affecting documentation and commentary
+
+ tz-link.htm says why governments should give plenty of notice for
+ time zone or DST changes, and refers to Matt Johnson's blog post.
+
+ tz-link.htm mentions Tzdata for Elixir. (Thanks to Matt Johnson.)
+
+
+Release 2016d - 2016-04-17 22:50:29 -0700
+
+ Changes affecting future time stamps
+
+ America/Caracas switches from -0430 to -04 on 2016-05-01 at 02:30.
+ (Thanks to Alexander Krivenyshev for the heads-up.)
+
+ Asia/Magadan switches from +10 to +11 on 2016-04-24 at 02:00.
+ (Thanks to Alexander Krivenyshev and Matt Johnson.)
+
+ New zone Asia/Tomsk, split off from Asia/Novosibirsk. It covers
+ Tomsk Oblast, Russia, which switches from +06 to +07 on 2016-05-29
+ at 02:00. (Thanks to Stepan Golosunov.)
+
+ Changes affecting past time stamps
+
+ New zone Europe/Kirov, split off from Europe/Volgograd. It covers
+ Kirov Oblast, Russia, which switched from +04/+05 to +03/+04 on
+ 1989-03-26 at 02:00, roughly a year after Europe/Volgograd made
+ the same change. (Thanks to Stepan Golosunov.)
+
+ Russia and nearby locations had daylight-saving transitions on
+ 1992-03-29 at 02:00 and 1992-09-27 at 03:00, instead of on
+ 1992-03-28 at 23:00 and 1992-09-26 at 23:00. (Thanks to Stepan
+ Golosunov.)
+
+ Many corrections to historical time in Kazakhstan from 1991
+ through 2005. (Thanks to Stepan Golosunov.) Replace Kazakhstan's
+ invented time zone abbreviations with numeric abbreviations.
+
+ Changes to commentary
+
+ Mention Internet RFCs 7808 (TZDIST) and 7809 (CalDAV time zone references).
+
+
+Release 2016c - 2016-03-23 00:51:27 -0700
+
+ Changes affecting future time stamps
+
+ Azerbaijan no longer observes DST. (Thanks to Steffen Thorsen.)
+
+ Chile reverts from permanent to seasonal DST. (Thanks to Juan
+ Correa for the heads-up, and to Tim Parenti for corrections.)
+ Guess that future transitions are August's and May's second
+ Saturdays at 24:00 mainland time. Also, call the period from
+ 2014-09-07 through 2016-05-14 daylight saving time instead of
+ standard time, as that seems more appropriate now.
+
+ Changes affecting past time stamps
+
+ Europe/Kaliningrad and Europe/Vilnius changed from +03/+04 to
+ +02/+03 on 1989-03-26, not 1991-03-31. Europe/Volgograd changed
+ from +04/+05 to +03/+04 on 1988-03-27, not 1989-03-26.
+ (Thanks to Stepan Golosunov.)
+
+ Changes to commentary
+
+ Several updates and URLs for historical and proposed Russian changes.
+ (Thanks to Stepan Golosunov, Matt Johnson, and Alexander Krivenyshev.)
+
+
+Release 2016b - 2016-03-12 17:30:14 -0800
+
+ Compatibility note
+
+ Starting with release 2016b, some data entries cause zic implementations
+ derived from tz releases 2005j through 2015e to issue warnings like
+ "time zone abbreviation differs from POSIX standard (+03)".
+ These warnings should not otherwise affect zic's output and can safely be
+ ignored on today's platforms, as the warnings refer to a restriction in
+ POSIX.1-1988 that was removed in POSIX.1-2001. One way to suppress the
+ warnings is to upgrade to zic derived from tz releases 2015f and later.
+
+ Changes affecting future time stamps
+
+ New zones Europe/Astrakhan and Europe/Ulyanovsk for Astrakhan and
+ Ulyanovsk Oblasts, Russia, both of which will switch from +03 to +04 on
+ 2016-03-27 at 02:00 local time. They need distinct zones since their
+ post-1970 histories disagree. New zone Asia/Barnaul for Altai Krai and
+ Altai Republic, Russia, which will switch from +06 to +07 on the same date
+ and local time. The Astrakhan change is already official; the others have
+ passed the first reading in the State Duma and are extremely likely.
+ Also, Asia/Sakhalin moves from +10 to +11 on 2016-03-27 at 02:00.
+ (Thanks to Alexander Krivenyshev for the heads-up, and to Matt Johnson
+ and Stepan Golosunov for followup.)
+
+ As a trial of a new system that needs less information to be made up,
+ the new zones use numeric time zone abbreviations like "+04"
+ instead of invented abbreviations like "ASTT".
+
+ Haiti will not observe DST in 2016. (Thanks to Jean Antoine via
+ Steffen Thorsen.)
+
+ Palestine's spring-forward transition on 2016-03-26 is at 01:00, not 00:00.
+ (Thanks to Hannah Kreitem.) Guess future transitions will be March's last
+ Saturday at 01:00, not March's last Friday at 24:00.
+
+ Changes affecting past time stamps
+
+ Europe/Chisinau observed DST during 1990, and switched from +04 to
+ +03 at 1990-05-06 02:00, instead of switching from +03 to +02.
+ (Thanks to Stepan Golosunov.)
+
+ 1991 abbreviations in Europe/Samara should be SAMT/SAMST, not
+ KUYT/KUYST. (Thanks to Stepan Golosunov.)
+
+ Changes to code
+
+ tzselect's diagnostics and checking, and checktab.awk's checking,
+ have been improved. (Thanks to J William Piggott.)
+
+ tzcode now builds under MinGW. (Thanks to Ian Abbott and Esben Haabendal.)
+
+ tzselect now tests Julian-date TZ settings more accurately.
+ (Thanks to J William Piggott.)
+
+ Changes to commentary
+
+ Comments in zone tables have been improved. (Thanks to J William Piggott.)
+
+ tzselect again limits its menu comments so that menus fit on a
+ 24×80 alphanumeric display.
+
+ A new web page tz-how-to.html. (Thanks to Bill Seymour.)
+
+ In the Theory file, the description of possible time zone abbreviations in
+ tzdata has been cleaned up, as the old description was unclear and
+ inconsistent. (Thanks to Alain Mouette for reporting the problem.)
+
+
+Release 2016a - 2016-01-26 23:28:02 -0800
+
+ Changes affecting future time stamps
+
+ America/Cayman will not observe daylight saving this year after all.
+ Revert our guess that it would. (Thanks to Matt Johnson.)
+
+ Asia/Chita switches from +0800 to +0900 on 2016-03-27 at 02:00.
+ (Thanks to Alexander Krivenyshev.)
+
+ Asia/Tehran now has DST predictions for the year 2038 and later,
+ to be March 21 00:00 to September 21 00:00. This is likely better
+ than predicting no DST, albeit off by a day every now and then.
+
+ Changes affecting past and future time stamps
+
+ America/Metlakatla switched from PST all year to AKST/AKDT on
+ 2015-11-01 at 02:00. (Thanks to Steffen Thorsen.)
+
+ America/Santa_Isabel has been removed, and replaced with a
+ backward compatibility link to America/Tijuana. Its contents were
+ apparently based on a misreading of Mexican legislation.
+
+ Changes affecting past time stamps
+
+ Asia/Karachi's two transition times in 2002 were off by a minute.
+ (Thanks to Matt Johnson.)
+
+ Changes affecting build procedure
+
+ An installer can now combine leap seconds with use of the backzone file,
+ e.g., with 'make PACKRATDATA=backzone REDO=posix_right zones'.
+ The old 'make posix_packrat' rule is now marked as obsolescent.
+ (Thanks to Ian Abbott for an initial implementation.)
+
+ Changes affecting documentation and commentary
+
+ A new file LICENSE makes it easier to see that the code and data
+ are mostly public-domain. (Thanks to James Knight.) The three
+ non-public-domain files now use the current (3-clause) BSD license
+ instead of older versions of that license.
+
+ tz-link.htm mentions the BDE library (thanks to Andrew Paprocki),
+ CCTZ (thanks to Tim Parenti), TimeJones.com, and has a new section
+ on editing tz source files (with a mention of Sublime zoneinfo,
+ thanks to Gilmore Davidson).
+
+ The Theory and asia files now mention the 2015 book "The Global
+ Transformation of Time, 1870-1950", and cite a couple of reviews.
+
+ The America/Chicago entry now documents the informal use of US
+ central time in Fort Pierre, South Dakota. (Thanks to Rick
+ McDermid, Matt Johnson, and Steve Jones.)
+
+
+Release 2015g - 2015-10-01 00:39:51 -0700
+
+ Changes affecting future time stamps
+
+ Turkey's 2015 fall-back transition is scheduled for Nov. 8, not Oct. 25.
+ (Thanks to Fatih.)
+
+ Norfolk moves from +1130 to +1100 on 2015-10-04 at 02:00 local time.
+ (Thanks to Alexander Krivenyshev.)
+
+ Fiji's 2016 fall-back transition is scheduled for January 17, not 24.
+ (Thanks to Ken Rylander.)
+
+ Fort Nelson, British Columbia will not fall back on 2015-11-01. It has
+ effectively been on MST (-0700) since it advanced its clocks on 2015-03-08.
+ New zone America/Fort_Nelson. (Thanks to Matt Johnson.)
+
+ Changes affecting past time stamps
+
+ Norfolk observed DST from 1974-10-27 02:00 to 1975-03-02 02:00.
+
+ Changes affecting code
+
+ localtime no longer mishandles America/Anchorage after 2037.
+ (Thanks to Bradley White for reporting the bug.)
+
+ On hosts with signed 32-bit time_t, localtime no longer mishandles
+ Pacific/Fiji after 2038-01-16 14:00 UTC.
+
+ The localtime module allows the variables 'timezone', 'daylight',
+ and 'altzone' to be in common storage shared with other modules,
+ and declares them in case the system <time.h> does not.
+ (Problems reported by Kees Dekker.)
+
+ On platforms with tm_zone, strftime.c now assumes it is not NULL.
+ This simplifies the code and is consistent with zdump.c.
+ (Problem reported by Christos Zoulas.)
+
+ Changes affecting documentation
+
+ The tzfile man page now documents that transition times denote the
+ starts (not the ends) of the corresponding time periods.
+ (Ambiguity reported by Bill Seymour.)
+
+
+Release 2015f - 2015-08-10 18:06:56 -0700
+
+ Changes affecting future time stamps
+
+ North Korea switches to +0830 on 2015-08-15. (Thanks to Steffen Thorsen.)
+ The abbreviation remains "KST". (Thanks to Robert Elz.)
+
+ Uruguay no longer observes DST. (Thanks to Steffen Thorsen
+ and Pablo Camargo.)
+
+ Changes affecting past and future time stamps
+
+ Moldova starts and ends DST at 00:00 UTC, not at 01:00 UTC.
+ (Thanks to Roman Tudos.)
+
+ Changes affecting data format and code
+
+ zic's '-y YEARISTYPE' option is no longer documented. The TYPE
+ field of a Rule line should now be '-'; the old values 'even',
+ 'odd', 'uspres', 'nonpres', 'nonuspres' were already undocumented.
+ Although the implementation has not changed, these features do not
+ work in the default installation, they are not used in the data,
+ and they are now considered obsolescent.
+
+ zic now checks that two rules don't take effect at the same time.
+ (Thanks to Jon Skeet and Arthur David Olson.) Constraints on
+ simultaneity are now documented.
+
+ The two characters '%z' in a zone format now stand for the UT
+ offset, e.g., '-07' for seven hours behind UT and '+0530' for
+ five hours and thirty minutes ahead. This better supports time
+ zone abbreviations conforming to POSIX.1-2001 and later.
+
+ Changes affecting installed data files
+
+ Comments for America/Halifax and America/Glace_Bay have been improved.
+ (Thanks to Brian Inglis.)
+
+ Data entries have been simplified for Atlantic/Canary, Europe/Simferopol,
+ Europe/Sofia, and Europe/Tallinn. This yields slightly smaller
+ installed data files for Europe/Simferopol and Europe/Tallinn.
+ It does not affect timestamps. (Thanks to Howard Hinnant.)
+
+ Changes affecting code
+
+ zdump and zic no longer warn about valid time zone abbreviations
+ like '-05'.
+
+ Some Visual Studio 2013 warnings have been suppressed.
+ (Thanks to Kees Dekker.)
+
+ 'date' no longer sets the time of day and its -a, -d, -n and -t
+ options have been removed. Long obsolescent, the implementation
+ of these features had porting problems. Builders no longer need
+ to configure HAVE_ADJTIME, HAVE_SETTIMEOFDAY, or HAVE_UTMPX_H.
+ (Thanks to Kees Dekker for pointing out the problem.)
+
+ Changes affecting documentation
+
+ The Theory file mentions naming issues earlier, as these seem to be
+ poorly publicized (thanks to Gilmore Davidson for reporting the problem).
+
+ tz-link.htm mentions Time Zone Database Parser (thanks to Howard Hinnant).
+
+ Mention that Herbert Samuel introduced the term "Summer Time".
+
+
+Release 2015e - 2015-06-13 10:56:02 -0700
+
+ Changes affecting future time stamps
+
+ Morocco will suspend DST from 2015-06-14 03:00 through 2015-07-19 02:00,
+ not 06-13 and 07-18 as we had guessed. (Thanks to Milamber.)
+
+ Assume Cayman Islands will observe DST starting next year, using US rules.
+ Although it isn't guaranteed, it is the most likely.
+
+ Changes affecting data format
+
+ The file 'iso3166.tab' now uses UTF-8, so that its entries can better
+ spell the names of Åland Islands, Côte d'Ivoire, and Réunion.
+
+ Changes affecting code
+
+ When displaying data, tzselect converts it to the current locale's
+ encoding if the iconv command works. (Problem reported by random832.)
+
+ tzselect no longer mishandles Dominica, fixing a bug introduced
+ in Release 2014f. (Problem reported by Owen Leibman.)
+
+ zic -l no longer fails when compiled with -DTZDEFAULT=\"/etc/localtime\".
+ This fixes a bug introduced in Release 2014f.
+ (Problem reported by Leonardo Chiquitto.)
+
+
+Release 2015d - 2015-04-24 08:09:46 -0700
+
+ Changes affecting future time stamps
+
+ Egypt will not observe DST in 2015 and will consider canceling it
+ permanently. For now, assume no DST indefinitely.
+ (Thanks to Ahmed Nazmy and Tim Parenti.)
+
+ Changes affecting past time stamps
+
+ America/Whitehorse switched from UT -09 to -08 on 1967-05-28, not
+ 1966-07-01. Also, Yukon's time zone history is documented better.
+ (Thanks to Brian Inglis and Dennis Ferguson.)
+
+ Change affecting past and future time zone abbreviations
+
+ The abbreviations for Hawaii-Aleutian standard and daylight times
+ have been changed from HAST/HADT to HST/HDT, as per US Government
+ Printing Office style. This affects only America/Adak since 1983,
+ as America/Honolulu was already using the new style.
+
+ Changes affecting code
+
+ zic has some minor performance improvements.
+
+
+Release 2015c - 2015-04-11 08:55:55 -0700
+
+ Changes affecting future time stamps
+
+ Egypt's spring-forward transition is at 24:00 on April's last Thursday,
+ not 00:00 on April's last Friday. 2015's transition will therefore be on
+ Thursday, April 30 at 24:00, not Friday, April 24 at 00:00. Similar fixes
+ apply to 2026, 2037, 2043, etc. (Thanks to Steffen Thorsen.)
+
+ Changes affecting past time stamps
+
+ The following changes affect some pre-1991 Chile-related time stamps
+ in America/Santiago, Antarctica/Palmer, and Pacific/Easter.
+
+ The 1910 transition was January 10, not January 1.
+
+ The 1918 transition was September 10, not September 1.
+
+ The UT -04 time observed from 1932 to 1942 is now considered to
+ be standard time, not year-round DST.
+
+ Santiago observed DST (UT -03) from 1946-07-15 through
+ 1946-08-31, then reverted to standard time, then switched to -05
+ on 1947-04-01.
+
+ Assume transitions before 1968 were at 00:00, since we have no data
+ saying otherwise.
+
+ The spring 1988 transition was 1988-10-09, not 1988-10-02.
+ The fall 1990 transition was 1990-03-11, not 1990-03-18.
+
+ Assume no UT offset change for Pacific/Easter on 1890-01-01,
+ and omit all transitions on Pacific/Easter from 1942 through 1946
+ since we have no data suggesting that they existed.
+
+ One more zone has been turned into a link, as it differed
+ from an existing zone only for older time stamps. As usual,
+ this change affects UT offsets in pre-1970 time stamps only.
+ The zone's old contents have been moved to the 'backzone' file.
+ The affected zone is America/Montreal.
+
+ Changes affecting commentary
+
+ Mention the TZUpdater tool.
+
+ Mention "The Time Now". (Thanks to Brandon Ramsey.)
+
+
+Release 2015b - 2015-03-19 23:28:11 -0700
+
+ Changes affecting future time stamps
+
+ Mongolia will start observing DST again this year, from the last
+ Saturday in March at 02:00 to the last Saturday in September at 00:00.
+ (Thanks to Ganbold Tsagaankhuu.)
+
+ Palestine will start DST on March 28, not March 27. Also,
+ correct the fall 2014 transition from September 26 to October 24.
+ Adjust future predictions accordingly. (Thanks to Steffen Thorsen.)
+
+ Changes affecting past time stamps
+
+ The 1982 zone shift in Pacific/Easter has been corrected, fixing a 2015a
+ regression. (Thanks to Stuart Bishop for reporting the problem.)
+
+ Some more zones have been turned into links, when they differed
+ from existing zones only for older time stamps. As usual,
+ these changes affect UT offsets in pre-1970 time stamps only.
+ Their old contents have been moved to the 'backzone' file.
+ The affected zones are: America/Antigua, America/Cayman,
+ Pacific/Midway, and Pacific/Saipan.
+
+ Changes affecting time zone abbreviations
+
+ Correct the 1992-2010 DST abbreviation in Volgograd from "MSK" to "MSD".
+ (Thanks to Hank W.)
+
+ Changes affecting code
+
+ Fix integer overflow bug in reference 'mktime' implementation.
+ (Problem reported by Jörg Richter.)
+
+ Allow -Dtime_tz=time_t compilations, and allow -Dtime_tz=... libraries
+ to be used in the same executable as standard-library time_t functions.
+ (Problems reported by Bradley White.)
+
+ Changes affecting commentary
+
+ Cite the recent Mexican decree changing Quintana Roo's time zone.
+ (Thanks to Carlos Raúl Perasso.)
+
+ Likewise for the recent Chilean decree. (Thanks to Eduardo Romero Urra.)
+
+ Update info about Mars time.
+
+
+Release 2015a - 2015-01-29 22:35:20 -0800
+
+ Changes affecting future time stamps
+
+ The Mexican state of Quintana Roo, represented by America/Cancun,
+ will shift from Central Time with DST to Eastern Time without DST
+ on 2015-02-01 at 02:00. (Thanks to Steffen Thorsen and Gwillim Law.)
+
+ Chile will not change clocks in April or thereafter; its new standard time
+ will be its old daylight saving time. This affects America/Santiago,
+ Pacific/Easter, and Antarctica/Palmer. (Thanks to Juan Correa.)
+
+ New leap second 2015-06-30 23:59:60 UTC as per IERS Bulletin C 49.
+ (Thanks to Tim Parenti.)
+
+ Changes affecting past time stamps
+
+ Iceland observed DST in 1919 and 1921, and its 1939 fallback
+ transition was Oct. 29, not Nov. 29. Remove incorrect data from
+ Shanks about time in Iceland between 1837 and 1908.
+
+ Some more zones have been turned into links, when they differed
+ from existing zones only for older time stamps. As usual,
+ these changes affect UT offsets in pre-1970 time stamps only.
+ Their old contents have been moved to the 'backzone' file.
+ The affected zones are: Asia/Aden, Asia/Bahrain, Asia/Kuwait,
+ and Asia/Muscat.
+
+ Changes affecting code
+
+ tzalloc now scrubs time zone abbreviations compatibly with the way
+ that tzset always has, by replacing invalid bytes with '_' and by
+ shortening too-long abbreviations.
+
+ tzselect ports to POSIX awk implementations, no longer mishandles
+ POSIX TZ settings when GNU awk is used, and reports POSIX TZ
+ settings to the user. (Thanks to Stefan Kuhn.)
+
+ Changes affecting build procedure
+
+ 'make check' now checks for links to links in the data.
+ One such link (for Africa/Asmera) has been fixed.
+ (Thanks to Stephen Colebourne for pointing out the problem.)
+
+ Changes affecting commentary
+
+ The leapseconds file commentary now mentions the expiration date.
+ (Problem reported by Martin Burnicki.)
+
+ Update Mexican Library of Congress URL.
+
+
+Release 2014j - 2014-11-10 17:37:11 -0800
+
+ Changes affecting current and future time stamps
+
+ Turks & Caicos' switch from US eastern time to UT -04 year-round
+ did not occur on 2014-11-02 at 02:00. It's currently scheduled
+ for 2015-11-01 at 02:00. (Thanks to Chris Walton.)
+
+ Changes affecting past time stamps
+
+ Many pre-1989 time stamps have been corrected for Asia/Seoul and
+ Asia/Pyongyang, based on sources for the Korean-language Wikipedia
+ entry for time in Korea. (Thanks to Sanghyuk Jung.) Also, no
+ longer guess that Pyongyang mimicked Seoul time after World War II,
+ as this is politically implausible.
+
+ Some more zones have been turned into links, when they differed
+ from existing zones only for older time stamps. As usual,
+ these changes affect UT offsets in pre-1970 time stamps only.
+ Their old contents have been moved to the 'backzone' file.
+ The affected zones are: Africa/Addis_Ababa, Africa/Asmara,
+ Africa/Dar_es_Salaam, Africa/Djibouti, Africa/Kampala,
+ Africa/Mogadishu, Indian/Antananarivo, Indian/Comoro, and
+ Indian/Mayotte.
+
+ Changes affecting commentary
+
+ The commentary is less enthusiastic about Shanks as a source,
+ and is more careful to distinguish UT from UTC.
+
+
+Release 2014i - 2014-10-21 22:04:57 -0700
+
+ Changes affecting future time stamps
+
+ Pacific/Fiji will observe DST from 2014-11-02 02:00 to 2015-01-18 03:00.
+ (Thanks to Ken Rylander for the heads-up.) Guess that future
+ years will use a similar pattern.
+
+ A new Zone Pacific/Bougainville, for the part of Papua New Guinea
+ that plans to switch from UT +10 to +11 on 2014-12-28 at 02:00.
+ (Thanks to Kiley Walbom for the heads-up.)
+
+ Changes affecting time zone abbreviations
+
+ Since Belarus is not changing its clocks even though Moscow is,
+ the time zone abbreviation in Europe/Minsk is changing from FET
+ to its more-traditional value MSK on 2014-10-26 at 01:00.
+ (Thanks to Alexander Bokovoy for the heads-up about Belarus.)
+
+ The new abbreviation IDT stands for the pre-1976 use of UT +08 in
+ Indochina, to distinguish it better from ICT (+07).
+
+ Changes affecting past time stamps
+
+ Many time stamps have been corrected for Asia/Ho_Chi_Minh before 1976
+ (thanks to Trần Ngọc Quân for an indirect pointer to Trần Tiến Bình's
+ authoritative book). Asia/Ho_Chi_Minh has been added to
+ zone1970.tab, to give tzselect users in Vietnam two choices,
+ since north and south Vietnam disagreed after our 1970 cutoff.
+
+ Asia/Phnom_Penh and Asia/Vientiane have been turned into links, as
+ they differed from existing zones only for older time stamps. As
+ usual, these changes affect pre-1970 time stamps only. Their old
+ contents have been moved to the 'backzone' file.
+
+ Changes affecting code
+
+ The time-related library functions now set errno on failure, and
+ some crashes in the new tzalloc-related library functions have
+ been fixed. (Thanks to Christos Zoulas for reporting most of
+ these problems and for suggesting fixes.)
+
+ If USG_COMPAT is defined and the requested timestamp is standard time,
+ the tz library's localtime and mktime functions now set the extern
+ variable timezone to a value appropriate for that timestamp; and
+ similarly for ALTZONE, daylight saving time, and the altzone variable.
+ This change is a companion to the tzname change in 2014h, and is
+ designed to make timezone and altzone more compatible with tzname.
+
+ The tz library's functions now set errno to EOVERFLOW if they fail
+ because the result cannot be represented. ctime and ctime_r now
+ return NULL and set errno when a timestamp is out of range, rather
+ than having undefined behavior.
+
+ Some bugs associated with the new 2014g functions have been fixed.
+ This includes a bug that largely incapacitated the new functions
+ time2posix_z and posix2time_z. (Thanks to Christos Zoulas.)
+ It also includes some uses of uninitialized variables after tzalloc.
+ The new code uses the standard type 'ssize_t', which the Makefile
+ now gives porting advice about.
+
+ Changes affecting commentary
+
+ Updated URLs for NRC Canada (thanks to Matt Johnson and Brian Inglis).
+
+
+Release 2014h - 2014-09-25 18:59:03 -0700
+
+ Changes affecting past timestamps
+
+ America/Jamaica's 1974 spring-forward transition was Jan. 6, not Apr. 28.
+
+ Shanks says Asia/Novokuznetsk switched from LMT (not "NMT") on 1924-05-01,
+ not 1920-01-06. The old entry was based on a misinterpretation of Shanks.
+
+ Some more zones have been turned into links, when they differed
+ from existing zones only for older timestamps. As usual,
+ these changes affect UT offsets in pre-1970 timestamps only.
+ Their old contents have been moved to the 'backzone' file.
+ The affected zones are: Africa/Blantyre, Africa/Bujumbura,
+ Africa/Gaborone, Africa/Harare, Africa/Kigali, Africa/Lubumbashi,
+ Africa/Lusaka, Africa/Maseru, and Africa/Mbabane.
+
+ Changes affecting code
+
+ zdump -V and -v now output gmtoff= values on all platforms,
+ not merely on platforms defining TM_GMTOFF.
+
+ The tz library's localtime and mktime functions now set tzname to a value
+ appropriate for the requested timestamp, and zdump now uses this
+ on platforms not defining TM_ZONE, fixing a 2014g regression.
+ (Thanks to Tim Parenti for reporting the problem.)
+
+ The tz library no longer sets tzname if localtime or mktime fails.
+
+ zdump -c no longer mishandles transitions near year boundaries.
+ (Thanks to Tim Parenti for reporting the problem.)
+
+ An access to uninitialized data has been fixed.
+ (Thanks to Jörg Richter for reporting the problem.)
+
+ When THREAD_SAFE is defined, the code ports to the C11 memory model.
+ A memory leak has been fixed if ALL_STATE and THREAD_SAFE are defined
+ and two threads race to initialize data used by gmtime-like functions.
+ (Thanks to Andy Heninger for reporting the problems.)
+
+ Changes affecting build procedure
+
+ 'make check' now checks better for properly-sorted data.
+
+ Changes affecting documentation and commentary
+
+ zdump's gmtoff=N output is now documented, and its isdst=D output
+ is now documented to possibly output D values other than 0 or 1.
+
+ zdump -c's treatment of years is now documented to use the
+ Gregorian calendar and Universal Time without leap seconds,
+ and its behavior at cutoff boundaries is now documented better.
+ (Thanks to Arthur David Olson and Tim Parenti for reporting the problems.)
+
+ Programs are now documented to use the proleptic Gregorian calendar.
+ (Thanks to Alan Barrett for the suggestion.)
+
+ Fractional-second GMT offsets have been documented for civil time
+ in 19th-century Chennai, Jakarta, and New York.
+
+
+Release 2014g - 2014-08-28 12:31:23 -0700
+
+ Changes affecting future timestamps
+
+ Turks & Caicos is switching from US eastern time to UT -04
+ year-round, modeled as a switch on 2014-11-02 at 02:00.
+ [As noted in 2014j, this switch was later delayed.]
+
+ Changes affecting past timestamps
+
+ Time in Russia or the USSR before 1926 or so has been corrected by
+ a few seconds in the following zones: Asia/Irkutsk,
+ Asia/Krasnoyarsk, Asia/Omsk, Asia/Samarkand, Asia/Tbilisi,
+ Asia/Vladivostok, Asia/Yakutsk, Europe/Riga, Europe/Samara. For
+ Asia/Yekaterinburg the correction is a few minutes. (Thanks to
+ Vladimir Karpinsky.)
+
+ The Portuguese decree of 1911-05-26 took effect on 1912-01-01.
+ This affects 1911 timestamps in Africa/Bissau, Africa/Luanda,
+ Atlantic/Azores, and Atlantic/Madeira. Also, Lisbon's pre-1912
+ GMT offset was -0:36:45 (rounded from -0:36:44.68), not -0:36:32.
+ (Thanks to Stephen Colebourne for pointing to the decree.)
+
+ Asia/Dhaka ended DST on 2009-12-31 at 24:00, not 23:59.
+
+ A new file 'backzone' contains data which may appeal to
+ connoisseurs of old timestamps, although it is out of scope for
+ the tz database, is often poorly sourced, and contains some data
+ that is known to be incorrect. The new file is not recommended
+ for ordinary use and its entries are not installed by default.
+ (Thanks to Lester Caine for the high-quality Jersey, Guernsey, and
+ Isle of Man entries.)
+
+ Some more zones have been turned into links, when they differed
+ from existing zones only for older timestamps. As usual,
+ these changes affect UT offsets in pre-1970 timestamps only.
+ Their old contents have been moved to the 'backzone' file.
+ The affected zones are: Africa/Bangui, Africa/Brazzaville,
+ Africa/Douala, Africa/Kinshasa, Africa/Libreville, Africa/Luanda,
+ Africa/Malabo, Africa/Niamey, and Africa/Porto-Novo.
+
+ Changes affecting code
+
+ Unless NETBSD_INSPIRED is defined to 0, the tz library now
+ supplies functions for creating and using objects that represent
+ time zones. The new functions are tzalloc, tzfree, localtime_rz,
+ mktime_z, and (if STD_INSPIRED is also defined) posix2time_z and
+ time2posix_z. They are intended for performance: for example,
+ localtime_rz (unlike localtime_r) is trivially thread-safe without
+ locking. (Thanks to Christos Zoulas for proposing NetBSD-inspired
+ functions, and to Alan Barrett and Jonathan Lennox for helping to
+ debug the change.)
+
+ zdump now builds with the tz library unless USE_LTZ is defined to 0,
+ This lets zdump use tz features even if the system library lacks them.
+ To build zdump with the system library, use 'make CFLAGS=-DUSE_LTZ=0
+ TZDOBJS=zdump.o CHECK_TIME_T_ALTERNATIVES='.
+
+ zdump now uses localtime_rz if available, as it's significantly faster,
+ and it can help zdump better diagnose invalid time zone names.
+ Define HAVE_LOCALTIME_RZ to 0 to suppress this. HAVE_LOCALTIME_RZ
+ defaults to 1 if NETBSD_INSPIRED && USE_LTZ. When localtime_rz is
+ not available, zdump now uses localtime_r and tzset if available,
+ as this is a bit cleaner and faster than plain localtime. Compile
+ with -DHAVE_LOCALTIME_R=0 and/or -DHAVE_TZSET=0 if your system
+ lacks these two functions.
+
+ If THREAD_SAFE is defined to 1, the tz library is now thread-safe.
+ Although not needed for tz's own applications, which are single-threaded,
+ this supports POSIX better if the tz library is used in multithreaded apps.
+
+ Some crashes have been fixed when zdump or the tz library is given
+ invalid or outlandish input.
+
+ The tz library no longer mishandles leap seconds on platforms with
+ unsigned time_t in time zones that lack ordinary transitions after 1970.
+
+ The tz code now attempts to infer TM_GMTOFF and TM_ZONE if not
+ already defined, to make it easier to configure on common platforms.
+ Define NO_TM_GMTOFF and NO_TM_ZONE to suppress this.
+
+ Unless the new macro UNINIT_TRAP is defined to 1, the tz code now
+ assumes that reading uninitialized memory yields garbage values
+ but does not cause other problems such as traps.
+
+ If TM_GMTOFF is defined and UNINIT_TRAP is 0, mktime is now
+ more likely to guess right for ambiguous timestamps near
+ transitions where tm_isdst does not change.
+
+ If HAVE_STRFTIME_L is defined to 1, the tz library now defines
+ strftime_l for compatibility with recent versions of POSIX.
+ Only the C locale is supported, though. HAVE_STRFTIME_L defaults
+ to 1 on recent POSIX versions, and to 0 otherwise.
+
+ tzselect -c now uses a hybrid distance measure that works better
+ in Africa. (Thanks to Alan Barrett for noting the problem.)
+
+ The C source code now ports to NetBSD when GCC_DEBUG_FLAGS is used,
+ or when time_tz is defined.
+
+ When HAVE_UTMPX_H is set the 'date' command now builds on systems
+ whose <utmpx.h> file does not define WTMPX_FILE, and when setting
+ the date it updates the wtmpx file if _PATH_WTMPX is defined.
+ This affects GNU/Linux and similar systems.
+
+ For easier maintenance later, some C code has been simplified,
+ some lint has been removed, and the code has been tweaked so that
+ plain 'make' is more likely to work.
+
+ The C type 'bool' is now used for boolean values, instead of 'int'.
+
+ The long-obsolete LOCALE_HOME code has been removed.
+
+ The long-obsolete 'gtime' function has been removed.
+
+ Changes affecting build procedure
+
+ 'zdump' no longer links in ialloc.o, as it's not needed.
+
+ 'make check_time_t_alternatives' no longer assumes GNU diff.
+
+ Changes affecting distribution tarballs
+
+ The files checktab.awk and zoneinfo2tdf.pl are now distributed in
+ the tzdata tarball instead of the tzcode tarball, since they help
+ maintain the data. The NEWS and Theory files are now also
+ distributed in the tzdata tarball, as they're relevant for data.
+ (Thanks to Alan Barrett for pointing this out.) Also, the
+ leapseconds.awk file is no longer distributed in the tzcode
+ tarball, since it belongs in the tzdata tarball (where 2014f
+ inadvertently also distributed it).
+
+ Changes affecting documentation and commentary
+
+ A new file CONTRIBUTING is distributed. (Thanks to Tim Parenti for
+ suggesting a CONTRIBUTING file, and to Tony Finch and Walter Harms
+ for debugging it.)
+
+ The man pages have been updated to use function prototypes,
+ to document thread-safe variants like localtime_r, and to document
+ the NetBSD-inspired functions tzalloc, tzfree, localtime_rz, and
+ mktime_z.
+
+ The fields in Link lines have been renamed to be more descriptive
+ and more like the parameters of 'ln'. LINK-FROM has become TARGET,
+ and LINK-TO has become LINK-NAME.
+
+ tz-link.htm mentions the IETF's tzdist working group; Windows
+ Runtime etc. (thanks to Matt Johnson); and HP-UX's tztab.
+
+ Some broken URLs have been fixed in the commentary. (Thanks to
+ Lester Caine.)
+
+ Commentary about Philippines DST has been updated, and commentary
+ on pre-1970 time in India has been added.
+
+
+Release 2014f - 2014-08-05 17:42:36 -0700
+
+ Changes affecting future timestamps
+
+ Russia will subtract an hour from most of its time zones on 2014-10-26
+ at 02:00 local time. (Thanks to Alexander Krivenyshev.)
+ There are a few exceptions: Magadan Oblast (Asia/Magadan) and Zabaykalsky
+ Krai are subtracting two hours; conversely, Chukotka Autonomous Okrug
+ (Asia/Anadyr), Kamchatka Krai (Asia/Kamchatka), Kemerovo Oblast
+ (Asia/Novokuznetsk), and the Samara Oblast and the Udmurt Republic
+ (Europe/Samara) are not changing their clocks. The changed zones are
+ Europe/Kaliningrad, Europe/Moscow, Europe/Simferopol, Europe/Volgograd,
+ Asia/Yekaterinburg, Asia/Omsk, Asia/Novosibirsk, Asia/Krasnoyarsk,
+ Asia/Irkutsk, Asia/Yakutsk, Asia/Vladivostok, Asia/Khandyga,
+ Asia/Sakhalin, and Asia/Ust-Nera; Asia/Magadan will have two hours
+ subtracted; and Asia/Novokuznetsk's time zone abbreviation is affected,
+ but not its UTC offset. Two zones are added: Asia/Chita (split
+ from Asia/Yakutsk, and also with two hours subtracted) and
+ Asia/Srednekolymsk (split from Asia/Magadan, but with only one hour
+ subtracted). (Thanks to Tim Parenti for much of the above.)
+
+ Changes affecting time zone abbreviations
+
+ Australian eastern time zone abbreviations are now AEST/AEDT not EST,
+ and similarly for the other Australian zones. That is, for eastern
+ standard and daylight saving time the abbreviations are AEST and AEDT
+ instead of the former EST for both; similarly, ACST/ACDT, ACWST/ACWDT,
+ and AWST/AWDT are now used instead of the former CST, CWST, and WST.
+ This change does not affect UT offsets, only time zone abbreviations.
+ (Thanks to Rich Tibbett and many others.)
+
+ Asia/Novokuznetsk shifts from NOVT to KRAT (remaining on UT +07)
+ effective 2014-10-26 at 02:00 local time.
+
+ The time zone abbreviation for Xinjiang Time (observed in Ürümqi)
+ has been changed from URUT to XJT. (Thanks to Luther Ma.)
+
+ Prefer MSK/MSD for Moscow time in Russia, even in other cities.
+ Similarly, prefer EET/EEST for eastern European time in Russia.
+
+ Change time zone abbreviations in (western) Samoa to use "ST" and
+ "DT" suffixes, as this is more likely to match common practice.
+ Prefix "W" to (western) Samoa time when its standard-time offset
+ disagrees with that of American Samoa.
+
+ America/Metlakatla now uses PST, not MeST, to abbreviate its time zone.
+
+ Time zone abbreviations have been updated for Japan's two time
+ zones used 1896-1937. JWST now stands for Western Standard
+ Time, and JCST for Central Standard Time (formerly this was CJT).
+ These abbreviations are now used for time in Korea, Taiwan,
+ and Sakhalin while controlled by Japan.
+
+ Changes affecting past timestamps
+
+ China's five zones have been simplified to two, since the post-1970
+ differences in the other three seem to have been imaginary. The
+ zones Asia/Harbin, Asia/Chongqing, and Asia/Kashgar have been
+ removed; backwards-compatibility links still work, albeit with
+ different behaviors for timestamps before May 1980. Asia/Urumqi's
+ 1980 transition to UT +08 has been removed, so that it is now at
+ +06 and not +08. (Thanks to Luther Ma and to Alois Treindl;
+ Treindl sent helpful translations of two papers by Guo Qingsheng.)
+
+ Some zones have been turned into links, when they differed from existing
+ zones only for older UT offsets where data entries were likely invented.
+ These changes affect UT offsets in pre-1970 timestamps only. This is
+ similar to the change in release 2013e, except this time for western
+ Africa. The affected zones are: Africa/Bamako, Africa/Banjul,
+ Africa/Conakry, Africa/Dakar, Africa/Freetown, Africa/Lome,
+ Africa/Nouakchott, Africa/Ouagadougou, Africa/Sao_Tome, and
+ Atlantic/St_Helena. This also affects the backwards-compatibility
+ link Africa/Timbuktu. (Thanks to Alan Barrett, Stephen Colebourne,
+ Tim Parenti, and David Patte for reporting problems in earlier
+ versions of this change.)
+
+ Asia/Shanghai's pre-standard-time UT offset has been changed from
+ 8:05:57 to 8:05:43, the location of Xujiahui Observatory. Its
+ transition to standard time has been changed from 1928 to 1901.
+
+ Asia/Taipei switched to JWST on 1896-01-01, then to JST on 1937-10-01,
+ then to CST on 1945-09-21 at 01:00, and did not observe DST in 1945.
+ In 1946 it observed DST from 05-15 through 09-30; in 1947
+ from 04-15 through 10-31; and in 1979 from 07-01 through 09-30.
+ (Thanks to Yu-Cheng Chuang.)
+
+ Asia/Riyadh's transition to standard time is now 1947-03-14, not 1950.
+
+ Europe/Helsinki's 1942 fall-back transition was 10-04 at 01:00, not
+ 10-03 at 00:00. (Thanks to Konstantin Hyppönen.)
+
+ Pacific/Pago_Pago has been changed from UT -11:30 to -11 for the
+ period from 1911 to 1950.
+
+ Pacific/Chatham has been changed to New Zealand standard time plus
+ 45 minutes for the period before 1957, reflecting a 1956 remark in
+ the New Zealand parliament.
+
+ Europe/Budapest has several pre-1946 corrections: in 1918 the transition
+ out of DST was on 09-16, not 09-29; in 1919 it was on 11-24, not 09-15; in
+ 1945 it was on 11-01, not 11-03; in 1941 the transition to DST was 04-08
+ not 04-06 at 02:00; and there was no DST in 1920.
+
+ Africa/Accra is now assumed to have observed DST from 1920 through 1935.
+
+ Time in Russia before 1927 or so has been corrected by a few seconds in
+ the following zones: Europe/Moscow, Asia/Irkutsk, Asia/Tbilisi,
+ Asia/Tashkent, Asia/Vladivostok, Asia/Yekaterinburg, Europe/Helsinki, and
+ Europe/Riga. Also, Moscow's location has been changed to its Kilometer 0
+ point. (Thanks to Vladimir Karpinsky for the Moscow changes.)
+
+ Changes affecting data format
+
+ A new file 'zone1970.tab' supersedes 'zone.tab' in the installed data.
+ The new file's extended format allows multiple country codes per zone.
+ The older file is still installed but is deprecated; its format is
+ not changing and it will still be distributed for a while, but new
+ applications should use the new file.
+
+ The new file format simplifies maintenance of obscure locations.
+ To test this, it adds coverage for the Crozet Islands and the
+ Scattered Islands. (Thanks to Tobias Conradi and Antoine Leca.)
+
+ The file 'iso3166.tab' is planned to switch from ASCII to UTF-8.
+ It is still ASCII now, but commentary about the switch has been added.
+ The new file 'zone1970.tab' already uses UTF-8.
+
+ Changes affecting code
+
+ 'localtime', 'mktime', etc. now use much less stack space if ALL_STATE
+ is defined. (Thanks to Elliott Hughes for reporting the problem.)
+
+ 'zic' no longer mishandles input when ignoring case in locales that
+ are not compatible with English, e.g., unibyte Turkish locales when
+ compiled with HAVE_GETTEXT.
+
+ Error diagnostics of 'zic' and 'yearistype' have been reworded so that
+ they no longer use ASCII '-' as if it were a dash.
+
+ 'zic' now rejects output file names that contain '.' or '..' components.
+ (Thanks to Tim Parenti for reporting the problem.)
+
+ 'zic -v' now warns about output file names that do not follow
+ POSIX rules, or that contain a digit or '.'. (Thanks to Arthur
+ David Olson for starting the ball rolling on this.)
+
+ Some lint has been removed when using GCC_DEBUG_FLAGS with GCC 4.9.0.
+
+ Changes affecting build procedure
+
+ 'zic' no longer links in localtime.o and asctime.o, as they're not needed.
+ (Thanks to John Cochran.)
+
+ Changes affecting documentation and commentary
+
+ The 'Theory' file documents legacy names, the longstanding
+ exceptions to the POSIX-inspired file name rules.
+
+ The 'zic' documentation clarifies the role of time types when
+ interpreting dates. (Thanks to Arthur David Olson.)
+
+ Documentation and commentary now prefer UTF-8 to US-ASCII,
+ allowing the use of proper accents in foreign words and names.
+ Code and data have not changed because of this. (Thanks to
+ Garrett Wollman, Ian Abbott, and Guy Harris for helping to debug
+ this.)
+
+ Non-HTML documentation and commentary now use plain-text URLs instead of
+ HTML insertions, and are more consistent about bracketing URLs when they
+ are not already surrounded by white space. (Thanks to suggestions by
+ Steffen Nurpmeso.)
+
+ There is new commentary about Xujiahui Observatory, the five time-zone
+ project in China from 1918 to 1949, timekeeping in Japanese-occupied
+ Shanghai, and Tibet Time in the 1950s. The sharp-eyed can spot the
+ warlord Jin Shuren in the data.
+
+ Commentary about the coverage of each Russian zone has been standardized.
+ (Thanks to Tim Parenti).
+
+ There is new commentary about contemporary timekeeping in Ethiopia.
+
+ Obsolete comments about a 2007 proposal for DST in Kuwait has been removed.
+
+ There is new commentary about time in Poland in 1919.
+
+ Proper credit has been given to DST inventor George Vernon Hudson.
+
+ Commentary about time in Metlakatla, AK and Resolute, NU has been
+ improved, with a new source for the former.
+
+ In zone.tab, Pacific/Easter no longer mentions Salas y Gómez, as it
+ is uninhabited.
+
+ Commentary about permanent Antarctic bases has been updated.
+
+ Several typos have been corrected. (Thanks to Tim Parenti for
+ contributing some of these fixes.)
+
+ tz-link.htm now mentions the JavaScript libraries Moment Timezone,
+ TimezoneJS.Date, Walltime-js, and Timezone. (Thanks to a heads-up
+ from Matt Johnson.) Also, it mentions the Go 'latlong' package.
+ (Thanks to a heads-up from Dirkjan Ochtman.)
+
+ The files usno1988, usno1989, usno1989a, usno1995, usno1997, and usno1998
+ have been removed. These obsolescent US Naval Observatory entries were no
+ longer helpful for maintenance. (Thanks to Tim Parenti for the suggestion.)
+
+
+Release 2014e - 2014-06-12 21:53:52 -0700
+
+ Changes affecting near-future timestamps
+
+ Egypt's 2014 Ramadan-based transitions are June 26 and July 31 at 24:00.
+ (Thanks to Imed Chihi.) Guess that from 2015 on Egypt will temporarily
+ switch to standard time at 24:00 the last Thursday before Ramadan, and
+ back to DST at 00:00 the first Friday after Ramadan.
+
+ Similarly, Morocco's are June 28 at 03:00 and August 2 at 02:00. (Thanks
+ to Milamber Space Network.) Guess that from 2015 on Morocco will
+ temporarily switch to standard time at 03:00 the last Saturday before
+ Ramadan, and back to DST at 02:00 the first Saturday after Ramadan.
+
+ Changes affecting past timestamps
+
+ The abbreviation "MSM" (Moscow Midsummer Time) is now used instead of
+ "MSD" for Moscow's double daylight time in summer 1921. Also, a typo
+ "VLASST" has been repaired to be "VLAST" for Vladivostok summer time
+ in 1991. (Thanks to Hank W. for reporting the problems.)
+
+ Changes affecting commentary
+
+ tz-link.htm now cites RFC 7265 for jCal, mentions PTP and the
+ draft CalDAV extension, updates URLs for TSP, TZInfo, IATA, and
+ removes stale pointers to World Time Explorer and WORLDTIME.
+
+
+Release 2014d - 2014-05-27 21:34:40 -0700
+
+ Changes affecting code
+
+ zic no longer generates files containing timestamps before the Big Bang.
+ This works around GNOME bug 730332
+ <https://bugzilla.gnome.org/show_bug.cgi?id=730332>.
+ (Thanks to Leonardo Chiquitto for reporting the bug, and to
+ Arthur David Olson and James Cloos for suggesting improvements to the fix.)
+
+ Changes affecting documentation
+
+ tz-link.htm now mentions GNOME.
+
+
+Release 2014c - 2014-05-13 07:44:13 -0700
+
+ Changes affecting near-future timestamps
+
+ Egypt observes DST starting 2014-05-15 at 24:00.
+ (Thanks to Ahmad El-Dardiry and Gunther Vermier.)
+ Details have not been announced, except that DST will not be observed
+ during Ramadan. Guess that DST will stop during the same Ramadan dates as
+ Morocco, and that Egypt's future spring and fall transitions will be the
+ same as 2010 when it last observed DST, namely April's last Friday at
+ 00:00 to September's last Thursday at 23:00 standard time. Also, guess
+ that Ramadan transitions will be at 00:00 standard time.
+
+ Changes affecting code
+
+ zic now generates transitions for minimum time values, eliminating guesswork
+ when handling low-valued timestamps. (Thanks to Arthur David Olson.)
+
+ Port to Cygwin sans glibc. (Thanks to Arthur David Olson.)
+
+ Changes affecting commentary and documentation
+
+ Remove now-confusing comment about Jordan. (Thanks to Oleksii Nochovnyi.)
+
+
+Release 2014b - 2014-03-24 21:28:50 -0700
+
+ Changes affecting near-future timestamps
+
+ Crimea switches to Moscow time on 2014-03-30 at 02:00 local time.
+ (Thanks to Alexander Krivenyshev.) Move its zone.tab entry from UA to RU.
+
+ New entry for Troll station, Antarctica. (Thanks to Paul-Inge Flakstad and
+ Bengt-Inge Larsson.) This is currently an approximation; a better version
+ will require the zic and localtime fixes mentioned below, and the plan is
+ to wait for a while until at least the zic fixes propagate.
+
+ Changes affecting code
+
+ 'zic' and 'localtime' no longer reject locations needing four transitions
+ per year for the foreseeable future. (Thanks to Andrew Main (Zefram).)
+ Also, 'zic' avoids some unlikely failures due to integer overflow.
+
+ Changes affecting build procedure
+
+ 'make check' now detects Rule lines defined but never used.
+ The NZAQ rules, an instance of this problem, have been removed.
+
+ Changes affecting commentary and documentation
+
+ Fix Tuesday/Thursday typo in description of time in Israel.
+ (Thanks to Bert Katz via Pavel Kharitonov and Mike Frysinger.)
+
+ Microsoft Windows 8.1 doesn't support tz database names. (Thanks
+ to Donald MacQueen.) Instead, the Microsoft Windows Store app
+ library supports them.
+
+ Add comments about Johnston Island time in the 1960s.
+ (Thanks to Lyle McElhaney.)
+
+ Morocco's 2014 DST start will be as predicted.
+ (Thanks to Sebastien Willemijns.)
+
+
+Release 2014a - 2014-03-07 23:30:29 -0800
+
+ Changes affecting near-future timestamps
+
+ Turkey begins DST on 2014-03-31, not 03-30. (Thanks to Faruk Pasin for
+ the heads-up, and to Tim Parenti for simplifying the update.)
+
+ Changes affecting past timestamps
+
+ Fiji ended DST on 2014-01-19 at 02:00, not the previously-scheduled 03:00.
+ (Thanks to Steffen Thorsen.)
+
+ Ukraine switched from Moscow to Eastern European time on 1990-07-01
+ (not 1992-01-01), and observed DST during the entire next winter.
+ (Thanks to Vladimir in Moscow via Alois Treindl.)
+
+ In 1988 Israel observed DST from 04-10 to 09-04, not 04-09 to 09-03.
+ (Thanks to Avigdor Finkelstein.)
+
+ Changes affecting code
+
+ A uninitialized-storage bug in 'localtime' has been fixed.
+ (Thanks to Logan Chien.)
+
+ Changes affecting the build procedure
+
+ The settings for 'make check_web' now default to Ubuntu 13.10.
+
+ Changes affecting commentary and documentation
+
+ The boundary of the US Pacific time zone is given more accurately.
+ (Thanks to Alan Mintz.)
+
+ Chile's 2014 DST will be as predicted. (Thanks to José Miguel Garrido.)
+
+ Paraguay's 2014 DST will be as predicted. (Thanks to Carlos Raúl Perasso.)
+
+ Better descriptions of countries with same time zone history as
+ Trinidad and Tobago since 1970. (Thanks to Alan Barrett for suggestion.)
+
+ Several changes affect tz-link.htm, the main web page.
+
+ Mention Time.is (thanks to Even Scharning) and WX-now (thanks to
+ David Braverman).
+
+ Mention xCal (Internet RFC 6321) and jCal.
+
+ Microsoft has some support for tz database names.
+
+ CLDR data formats include both XML and JSON.
+
+ Mention Maggiolo's map of solar vs standard time.
+ (Thanks to Arthur David Olson.)
+
+ Mention TZ4Net. (Thanks to Matt Johnson.)
+
+ Mention the timezone-olson Haskell package.
+
+ Mention zeitverschiebung.net. (Thanks to Martin Jäger.)
+
+ Remove moribund links to daylight-savings-time.info and to
+ Simple Timer + Clocks.
+
+ Update two links. (Thanks to Oscar van Vlijmen.)
+
+ Fix some formatting glitches, e.g., remove random newlines from
+ abbr elements' title attributes.
+
+
+Release 2013i - 2013-12-17 07:25:23 -0800
+
+ Changes affecting near-future timestamps:
+
+ Jordan switches back to standard time at 00:00 on December 20, 2013.
+ The 2006-2011 transition schedule is planned to resume in 2014.
+ (Thanks to Steffen Thorsen.)
+
+ Changes affecting past timestamps:
+
+ In 2004, Cuba began DST on March 28, not April 4.
+ (Thanks to Steffen Thorsen.)
+
+ Changes affecting code
+
+ The compile-time flag NOSOLAR has been removed, as nowadays the
+ benefit of slightly shrinking runtime table size is outweighed by the
+ cost of disallowing potential future updates that exceed old limits.
+
+ Changes affecting documentation and commentary
+
+ The files solar87, solar88, and solar89 are no longer distributed.
+ They were a negative experiment - that is, a demonstration that
+ tz data can represent solar time only with some difficulty and error.
+ Their presence in the distribution caused confusion, as Riyadh
+ civil time was generally not solar time in those years.
+
+ tz-link.htm now mentions Noda Time. (Thanks to Matt Johnson.)
+
+
+Release 2013h - 2013-10-25 15:32:32 -0700
+
+ Changes affecting current and future timestamps:
+
+ Libya has switched its UT offset back to +02 without DST, instead
+ of +01 with DST. (Thanks to Even Scharning.)
+
+ Western Sahara (Africa/El_Aaiun) uses Morocco's DST rules.
+ (Thanks to Gwillim Law.)
+
+ Changes affecting future timestamps:
+
+ Acre and (we guess) western Amazonas will switch from UT -04 to -05
+ on 2013-11-10. This affects America/Rio_Branco and America/Eirunepe.
+ (Thanks to Steffen Thorsen.)
+
+ Add entries for DST transitions in Morocco in the year 2038.
+ This avoids some year-2038 glitches introduced in 2013g.
+ (Thanks to Yoshito Umaoka for reporting the problem.)
+
+ Changes affecting API
+
+ The 'tzselect' command no longer requires the 'select' command,
+ and should now work with /bin/sh on more platforms. It also works
+ around a bug in BusyBox awk before version 1.21.0. (Thanks to
+ Patrick 'P. J.' McDermott and Alan Barrett.)
+
+ Changes affecting code
+
+ Fix localtime overflow bugs with 32-bit unsigned time_t.
+
+ zdump no longer assumes sscanf returns maximal values on overflow.
+
+ Changes affecting the build procedure
+
+ The builder can specify which programs to use, if any, instead of
+ 'ar' and 'ranlib', and libtz.a is now built locally before being
+ installed. (Thanks to Michael Forney.)
+
+ A dependency typo in the 'zdump' rule has been fixed.
+ (Thanks to Andrew Paprocki.)
+
+ The Makefile has been simplified by assuming that 'mkdir -p' and 'cp -f'
+ work as specified by POSIX.2-1992 or later; this is portable nowadays.
+
+ 'make clean' no longer removes 'leapseconds', since it's
+ host-independent and is part of the distribution.
+
+ The unused makefile macros TZCSRCS, TZDSRCS, DATESRCS have been removed.
+
+ Changes affecting documentation and commentary
+
+ tz-link.htm now mentions TC TIMEZONE's draft time zone service protocol
+ (thanks to Mike Douglass) and TimezoneJS.Date (thanks to Jim Fehrle).
+
+ Update URLs in tz-link page. Add URLs for Microsoft Windows, since
+ 8.1 introduces tz support. Remove URLs for Tru64 and UnixWare (no
+ longer maintained) and for old advisories. SOFA now does C.
+
+Release 2013g - 2013-09-30 21:08:26 -0700
+
+ Changes affecting current and near-future timestamps
+
+ Morocco now observes DST from the last Sunday in March to the last
+ Sunday in October, not April to September respectively. (Thanks
+ to Steffen Thorsen.)
+
+ Changes affecting 'zic'
+
+ 'zic' now runs on platforms that lack both hard links and symlinks.
+ (Thanks to Theo Veenker for reporting the problem, for MinGW.)
+ Also, fix some bugs on platforms that lack hard links but have symlinks.
+
+ 'zic -v' again warns that Asia/Tehran has no POSIX environment variable
+ to predict the far future, fixing a bug introduced in 2013e.
+
+ Changes affecting the build procedure
+
+ The 'leapseconds' file is again put into the tzdata tarball.
+ Also, 'leapseconds.awk', so tzdata is self-contained. (Thanks to
+ Matt Burgess and Ian Abbott.) The timestamps of these and other
+ dependent files in tarballs are adjusted more consistently.
+
+ Changes affecting documentation and commentary
+
+ The README file is now part of the data tarball as well as the code.
+ It now states that files are public domain unless otherwise specified.
+ (Thanks to Andrew Main (Zefram) for asking for clarifications.)
+ Its details about the 1989 release moved to a place of honor near
+ the end of NEWS.
+
+
+Release 2013f - 2013-09-24 23:37:36 -0700
+
+ Changes affecting near-future timestamps
+
+ Tocantins will very likely not observe DST starting this spring.
+ (Thanks to Steffen Thorsen.)
+
+ Jordan will likely stay at UT +03 indefinitely, and will not fall
+ back this fall.
+
+ Palestine will fall back at 00:00, not 01:00. (Thanks to Steffen Thorsen.)
+
+ Changes affecting API
+
+ The types of the global variables 'timezone' and 'altzone' (if present)
+ have been changed back to 'long'. This is required for 'timezone'
+ by POSIX, and for 'altzone' by common practice, e.g., Solaris 11.
+ These variables were originally 'long' in the tz code, but were
+ mistakenly changed to 'time_t' in 1987; nobody reported the
+ incompatibility until now. The difference matters on x32, where
+ 'long' is 32 bits and 'time_t' is 64. (Thanks to Elliott Hughes.)
+
+ Changes affecting the build procedure
+
+ Avoid long strings in leapseconds.awk to work around a mawk bug.
+ (Thanks to Cyril Baurand.)
+
+ Changes affecting documentation and commentary
+
+ New file 'NEWS' that contains release notes like this one.
+
+ Paraguay's law does not specify DST transition time; 00:00 is customary.
+ (Thanks to Waldemar Villamayor-Venialbo.)
+
+ Minor capitalization fixes.
+
+ Changes affecting version-control only
+
+ The experimental GitHub repository now contains annotated and
+ signed tags for recent releases, e.g., '2013e' for Release 2013e.
+ Releases are tagged starting with 2012e; earlier releases were
+ done differently, and tags would either not have a simple name or
+ not exactly match what was released.
+
+ 'make set-timestamps' is now simpler and a bit more portable.
+
+
+Release 2013e - 2013-09-19 23:50:04 -0700
+
+ Changes affecting near-future timestamps
+
+ This year Fiji will start DST on October 27, not October 20.
+ (Thanks to David Wheeler for the heads-up.) For now, guess that
+ Fiji will continue to spring forward the Sunday before the fourth
+ Monday in October.
+
+ Changes affecting current and future time zone abbreviations
+
+ Use WIB/WITA/WIT rather than WIT/CIT/EIT for alphabetic Indonesian
+ time zone abbreviations since 1932. (Thanks to George Ziegler,
+ Priyadi Iman Nurcahyo, Zakaria, Jason Grimes, Martin Pitt, and
+ Benny Lin.) This affects Asia/Dili, Asia/Jakarta, Asia/Jayapura,
+ Asia/Makassar, and Asia/Pontianak.
+
+ Use ART (UT -03, standard time), rather than WARST (also -03, but
+ daylight saving time) for San Luis, Argentina since 2009.
+
+ Changes affecting Godthåb timestamps after 2037 if version mismatch
+
+ Allow POSIX-like TZ strings where the transition time's hour can
+ range from -167 through 167, instead of the POSIX-required 0
+ through 24. E.g., TZ='FJT-12FJST,M10.3.1/146,M1.3.4/75' for the
+ new Fiji rules. This is a more-compact way to represent
+ far-future timestamps for America/Godthab, America/Santiago,
+ Antarctica/Palmer, Asia/Gaza, Asia/Hebron, Asia/Jerusalem,
+ Pacific/Easter, and Pacific/Fiji. Other zones are unaffected by
+ this change. (Derived from a suggestion by Arthur David Olson.)
+
+ Allow POSIX-like TZ strings where daylight saving time is in
+ effect all year. E.g., TZ='WART4WARST,J1/0,J365/25' for Western
+ Argentina Summer Time all year. This supports a more-compact way
+ to represent the 2013d data for America/Argentina/San_Luis.
+ Because of the change for San Luis noted above this change does not
+ affect the current data. (Thanks to Andrew Main (Zefram) for
+ suggestions that improved this change.)
+
+ Where these two TZ changes take effect, there is a minor extension
+ to the tz file format in that it allows new values for the
+ embedded TZ-format string, and the tz file format version number
+ has therefore been increased from 2 to 3 as a precaution.
+ Version-2-based client code should continue to work as before for
+ all timestamps before 2038. Existing version-2-based client code
+ (tzcode, GNU/Linux, Solaris) has been tested on version-3-format
+ files, and typically works in practice even for timestamps after
+ 2037; the only known exception is America/Godthab.
+
+ Changes affecting timestamps before 1970
+
+ Pacific/Johnston is now a link to Pacific/Honolulu. This corrects
+ some errors before 1947.
+
+ Some zones have been turned into links, when they differ from existing
+ zones only in older data entries that were likely invented or that
+ differ only in LMT or transitions from LMT. These changes affect
+ only timestamps before 1943. The affected zones are:
+ Africa/Juba, America/Anguilla, America/Aruba, America/Dominica,
+ America/Grenada, America/Guadeloupe, America/Marigot,
+ America/Montserrat, America/St_Barthelemy, America/St_Kitts,
+ America/St_Lucia, America/St_Thomas, America/St_Vincent,
+ America/Tortola, and Europe/Vaduz. (Thanks to Alois Treindl for
+ confirming that the old Europe/Vaduz zone was wrong and the new
+ link is better for WWII-era times.)
+
+ Change Kingston Mean Time from -5:07:12 to -5:07:11. This affects
+ America/Cayman, America/Jamaica and America/Grand_Turk timestamps
+ from 1890 to 1912.
+
+ Change the UT offset of Bern Mean Time from 0:29:44 to 0:29:46.
+ This affects Europe/Zurich timestamps from 1853 to 1894. (Thanks
+ to Alois Treindl).
+
+ Change the date of the circa-1850 Zurich transition from 1849-09-12
+ to 1853-07-16, overriding Shanks with data from Messerli about
+ postal and telegraph time in Switzerland.
+
+ Changes affecting time zone abbreviations before 1970
+
+ For Asia/Jakarta, use BMT (not JMT) for mean time from 1923 to 1932,
+ as Jakarta was called Batavia back then.
+
+ Changes affecting API
+
+ The 'zic' command now outputs a dummy transition when far-future
+ data can't be summarized using a TZ string, and uses a 402-year
+ window rather than a 400-year window. For the current data, this
+ affects only the Asia/Tehran file. It does not affect any of the
+ timestamps that this file represents, so zdump outputs the same
+ information as before. (Thanks to Andrew Main (Zefram).)
+
+ The 'date' command has a new '-r' option, which lets you specify
+ the integer time to display, a la FreeBSD.
+
+ The 'tzselect' command has two new options '-c' and '-n', which lets you
+ select a zone based on latitude and longitude.
+
+ The 'zic' command's '-v' option now warns about constructs that
+ require the new version-3 binary file format. (Thanks to Arthur
+ David Olson for the suggestion.)
+
+ Support for floating-point time_t has been removed.
+ It was always dicey, and POSIX no longer requires it.
+ (Thanks to Eric Blake for suggesting to the POSIX committee to
+ remove it, and thanks to Alan Barrett, Clive D.W. Feather, Andy
+ Heninger, Arthur David Olson, and Alois Treindl, for reporting
+ bugs and elucidating some of the corners of the old floating-point
+ implementation.)
+
+ The signatures of 'offtime', 'timeoff', and 'gtime' have been
+ changed back to the old practice of using 'long' to represent UT
+ offsets. This had been inadvertently and mistakenly changed to
+ 'int_fast32_t'. (Thanks to Christos Zoulas.)
+
+ The code avoids undefined behavior on integer overflow in some
+ more places, including gmtime, localtime, mktime and zdump.
+
+ Changes affecting the zdump utility
+
+ zdump now outputs "UT" when referring to Universal Time, not "UTC".
+ "UTC" does not make sense for timestamps that predate the introduction
+ of UTC, whereas "UT", a more-generic term, does. (Thanks to Steve Allen
+ for clarifying UT vs UTC.)
+
+ Data changes affecting behavior of tzselect and similar programs
+
+ Country code BQ is now called the more-common name "Caribbean Netherlands"
+ rather than the more-official "Bonaire, St Eustatius & Saba".
+
+ Remove from zone.tab the names America/Montreal, America/Shiprock,
+ and Antarctica/South_Pole, as they are equivalent to existing
+ same-country-code zones for post-1970 timestamps. The data entries for
+ these names are unchanged, so the names continue to work as before.
+
+ Changes affecting code internals
+
+ zic -c now runs way faster on 64-bit hosts when given large numbers.
+
+ zic now uses vfprintf to avoid allocating and freeing some memory.
+
+ tzselect now computes the list of continents from the data,
+ rather than have it hard-coded.
+
+ Minor changes pacify GCC 4.7.3 and GCC 4.8.1.
+
+ Changes affecting the build procedure
+
+ The 'leapseconds' file is now generated automatically from a
+ new file 'leap-seconds.list', which is a copy of
+ <ftp://ftp.nist.gov/pub/time/leap-seconds.list>
+ A new source file 'leapseconds.awk' implements this.
+ The goal is simplification of the future maintenance of 'leapseconds'.
+
+ When building the 'posix' or 'right' subdirectories, if the
+ subdirectory would be a copy of the default subdirectory, it is
+ now made a symbolic link if that is supported. This saves about
+ 2 MB of file system space.
+
+ The links America/Shiprock and Antarctica/South_Pole have been
+ moved to the 'backward' file. This affects only nondefault builds
+ that omit 'backward'.
+
+ Changes affecting version-control only
+
+ .gitignore now ignores 'date'.
+
+ Changes affecting documentation and commentary
+
+ Changes to the 'tzfile' man page
+
+ It now mentions that the binary file format may be extended in
+ future versions by appending data.
+
+ It now refers to the 'zdump' and 'zic' man pages.
+
+ Changes to the 'zic' man page
+
+ It lists conditions that elicit a warning with '-v'.
+
+ It says that the behavior is unspecified when duplicate names
+ are given, or if the source of one link is the target of another.
+
+ Its examples are updated to match the latest data.
+
+ The definition of white space has been clarified slightly.
+ (Thanks to Michael Deckers.)
+
+ Changes to the 'Theory' file
+
+ There is a new section about the accuracy of the tz database,
+ describing the many ways that errors can creep in, and
+ explaining why so many of the pre-1970 timestamps are wrong or
+ misleading (thanks to Steve Allen, Lester Caine, and Garrett
+ Wollman for discussions that contributed to this).
+
+ The 'Theory' file describes LMT better (this follows a
+ suggestion by Guy Harris).
+
+ It refers to the 2013 edition of POSIX rather than the 2004 edition.
+
+ It's mentioned that excluding 'backward' should not affect the
+ other data, and it suggests at least one zone.tab name per
+ inhabited country (thanks to Stephen Colebourne).
+
+ Some longstanding restrictions on names are documented, e.g.,
+ 'America/New_York' precludes 'America/New_York/Bronx'.
+
+ It gives more reasons for the 1970 cutoff.
+
+ It now mentions which time_t variants are supported, such as
+ signed integer time_t. (Thanks to Paul Goyette for reporting
+ typos in an experimental version of this change.)
+
+ (Thanks to Philip Newton for correcting typos in these changes.)
+
+ Documentation and commentary is more careful to distinguish UT in
+ general from UTC in particular. (Thanks to Steve Allen.)
+
+ Add a better source for the Zurich 1894 transition.
+ (Thanks to Pierre-Yves Berger.)
+
+ Update shapefile citations in tz-link.htm. (Thanks to Guy Harris.)
+
+
+Release 2013d - 2013-07-05 07:38:01 -0700
+
+ Changes affecting future timestamps:
+
+ Morocco's midsummer transitions this year are July 7 and August 10,
+ not July 9 and August 8. (Thanks to Andrew Paprocki.)
+
+ Israel now falls back on the last Sunday of October.
+ (Thanks to Ephraim Silverberg.)
+
+ Changes affecting past timestamps:
+
+ Specify Jerusalem's location more precisely; this changes the pre-1880
+ times by 2 s.
+
+ Changing affecting metadata only:
+
+ Fix typos in the entries for country codes BQ and SX.
+
+ Changes affecting code:
+
+ Rework the code to fix a bug with handling Australia/Macquarie on
+ 32-bit hosts (thanks to Arthur David Olson).
+
+ Port to platforms like NetBSD, where time_t can be wider than long.
+
+ Add support for testing time_t types other than the system's.
+ Run 'make check_time_t_alternatives' to try this out.
+ Currently, the tests fail for unsigned time_t;
+ this should get fixed at some point.
+
+ Changes affecting documentation and commentary:
+
+ Deemphasize the significance of national borders.
+
+ Update the zdump man page.
+
+ Remove obsolete NOID comment (thanks to Denis Excoffier).
+
+ Update several URLs and comments in the web pages.
+
+ Spelling fixes (thanks to Kevin Lyda and Jonathan Leffler).
+
+ Update URL for CLDR Zone->Tzid table (thanks to Yoshito Umaoka).
+
+
+Release 2013c - 2013-04-19 16:17:40 -0700
+
+ Changes affecting current and future timestamps:
+
+ Palestine observed DST starting March 29, 2013. (Thanks to
+ Steffen Thorsen.) From 2013 on, Gaza and Hebron both observe DST,
+ with the predicted rules being the last Thursday in March at 24:00
+ to the first Friday on or after September 21 at 01:00.
+
+ Assume that the recent change to Paraguay's DST rules is permanent,
+ by moving the end of DST to the 4th Sunday in March every year.
+ (Thanks to Carlos Raúl Perasso.)
+
+ Changes affecting past timestamps:
+
+ Fix some historical data for Palestine to agree with that of
+ timeanddate.com, as follows:
+
+ The spring 2008 change in Gaza and Hebron was on 00:00 Mar 28, not
+ 00:00 Apr 1.
+
+ The fall 2009 change in Gaza and Hebron on Sep 4 was at 01:00, not
+ 02:00.
+
+ The spring 2010 change in Hebron was 00:00 Mar 26, not 00:01 Mar 27.
+
+ The spring 2011 change in Gaza was 00:01 Apr 1, not 12:01 Apr 2.
+
+ The spring 2011 change in Hebron on Apr 1 was at 00:01, not 12:01.
+
+ The fall 2011 change in Hebron on Sep 30 was at 00:00, not 03:00.
+
+ Fix times of habitation for Macquarie to agree with the Tasmania
+ Parks & Wildlife Service history, which indicates that permanent
+ habitation was 1899-1919 and 1948 on.
+
+ Changing affecting metadata only:
+
+ Macquarie Island is politically part of Australia, not Antarctica.
+ (Thanks to Tobias Conradi.)
+
+ Sort Macquarie more-consistently with other parts of Australia.
+ (Thanks to Tim Parenti.)
+
+
+Release 2013b - 2013-03-10 22:33:40 -0700
+
+ Changes affecting current and future timestamps:
+
+ Haiti uses US daylight-saving rules this year, and presumably future years.
+ This changes timestamps starting today. (Thanks to Steffen Thorsen.)
+
+ Paraguay will end DST on March 24 this year.
+ (Thanks to Steffen Thorsen.) For now, assume it's just this year.
+
+ Morocco does not observe DST during Ramadan;
+ try to predict Ramadan in Morocco as best we can.
+ (Thanks to Erik Homoet for the heads-up.)
+
+ Changes affecting commentary:
+
+ Update URLs in tz-link page. Add URLs for webOS, BB10, iOS.
+ Update URL for Solaris. Mention Internet RFC 6557.
+ Update Internet RFCs 2445->5545, 2822->5322.
+ Switch from FTP to HTTP for Internet RFCs.
+
+
+Release 2013a - 2013-02-27 09:20:35 -0800
+
+ Change affecting binary data format:
+
+ The zone offset at the end of version-2-format zone files is now
+ allowed to be 24:00, as per POSIX.1-2008. (Thanks to Arthur David Olson.)
+
+ Changes affecting current and future timestamps:
+
+ Chile's 2013 rules, and we guess rules for 2014 and later, will be
+ the same as 2012, namely Apr Sun>=23 03:00 UTC to Sep Sun>=2 04:00 UTC.
+ (Thanks to Steffen Thorsen and Robert Elz.)
+
+ New Zones Asia/Khandyga, Asia/Ust-Nera, Europe/Busingen.
+ (Thanks to Tobias Conradi and Arthur David Olson.)
+
+ Many changes affect historical timestamps before 1940.
+ These were deduced from: Milne J. Civil time. Geogr J. 1899
+ Feb;13(2):173-94 <https://www.jstor.org/stable/1774359>.
+
+ Changes affecting the code:
+
+ Fix zic bug that mishandled Egypt's 2010 changes (this also affected
+ the data). (Thanks to Arthur David Olson.)
+
+ Fix localtime bug when time_t is unsigned and data files were generated
+ by a signed time_t system. (Thanks to Doug Bailey for reporting and
+ to Arthur David Olson for fixing.)
+
+ Allow the email address for bug reports to be set by the packager.
+ The default is tz@iana.org, as before. (Thanks to Joseph S. Myers.)
+
+ Update HTML checking to be compatible with Ubuntu 12.10.
+
+ Check that files are a safe subset of ASCII. At some point we may
+ relax this requirement to a safe subset of UTF-8. Without the
+ check, some non-UTF-8 encodings were leaking into the distribution.
+
+ Commentary changes:
+
+ Restore a comment about copyright notices that was inadvertently deleted.
+ (Thanks to Arthur David Olson.)
+
+ Improve the commentary about which districts observe what times
+ in Russia. (Thanks to Oscar van Vlijmen and Arthur David Olson).
+
+ Add web page links to tz.js.
+
+ Add "Run by the Monkeys" to tz-art. (Thanks to Arthur David Olson.)
+
+
+Release 2012j - 2012-11-12 18:34:49 -0800
+
+ Libya moved to CET this weekend, but with DST planned next year.
+ (Thanks to Even Scharning, Steffen Thorsen, and Tim Parenti.)
+
+ Signatures now have the extension .asc, not .sign, as that's more
+ standard. (Thanks to Phil Pennock.)
+
+ The output of 'zdump --version', and of 'zic --version', now
+ uses a format that is more typical for --version.
+ (Thanks to Joseph S. Myers.)
+
+ The output of 'tzselect --help', 'zdump --help', and 'zic --help'
+ now uses tz@iana.org rather than the old elsie address.
+
+ zic -v now complains about abbreviations that are less than 3
+ or more than 6 characters, as per Posix. Formerly, it checked
+ for abbreviations that were more than 3.
+
+ 'make public' no longer puts its temporary directory under /tmp,
+ and uses the just-built zic rather than the system zic.
+
+ Various fixes to documentation and commentary.
+
+
+Release 2012i - 2012-11-03 12:57:09 -0700
+
+ Cuba switches from DST tomorrow at 01:00. (Thanks to Steffen Thorsen.)
+
+ Linker flags can now be specified via LDFLAGS.
+ AWK now defaults to 'awk', not 'nawk'.
+ The shell in tzselect now defaults to /bin/bash, but this can
+ be overridden by specifying KSHELL.
+ The main web page now mentions the unofficial GitHub repository.
+ (Thanks to Mike Frysinger.)
+
+ Tarball signatures can now be built by running 'make signatures'.
+ There are also new makefile rules 'tarballs', 'check_public', and
+ separate makefile rules for each tarball and signature file.
+ A few makefile rules are now more portable to strict POSIX.
+
+ The main web page now lists the canonical IANA URL.
+
+
+Release 2012h - 2012-10-26 22:49:10 -0700
+
+ Bahia no longer has DST. (Thanks to Kelley Cook.)
+
+ Tocantins has DST. (Thanks to Rodrigo Severo.)
+
+ Israel has new DST rules next year. (Thanks to Ephraim Silverberg.)
+
+ Jordan stays on DST this winter. (Thanks to Steffen Thorsen.)
+
+ Web page updates.
+
+ More C modernization, except that at Arthur David Olson's suggestion
+ the instances of 'register' were kept.
+
+
+Release 2012g - 2012-10-17 20:59:45 -0700
+
+ Samoa fall 2012 and later. (Thanks to Nicholas Pereira and Robert Elz.)
+
+ Palestine fall 2012. (Thanks to Steffen Thorsen.)
+
+ Assume C89.
+
+ To attack the version-number problem, this release ships the file
+ 'Makefile' (which contains the release number) in both the tzcode and
+ the tzdata tarballs. The two Makefiles are identical, and should be
+ identical in any matching pair of tarballs, so it shouldn't matter
+ which order you extract the tarballs. Perhaps we can come up with a
+ better version-number scheme at some point; this scheme does have the
+ virtue of not adding more files.
+
+
+Release 2012f - 2012-09-12 23:17:03 -0700
+
+ * australasia (Pacific/Fiji): Fiji DST is October 21 through January
+ 20 this year. (Thanks to Steffen Thorsen.)
+
+
+Release 2012e - 2012-08-02 20:44:55 -0700
+
+ * australasia (Pacific/Fakaofo): Tokelau is UT +13, not +14.
+ (Thanks to Steffen Thorsen.)
+
+ * Use a single version number for both code and data.
+
+ * .gitignore: New file.
+
+ * Remove trailing white space.
+
+
+Release code2012c-data2012d - 2012-07-19 16:35:33 -0700
+
+ Changes for Morocco's timestamps, which take effect in a couple of
+ hours, along with infrastructure changes to accommodate how the tz
+ code and data are released on IANA.
+
+
+Release data2012c - 2012-03-27 12:17:25 -0400
+
+ africa
+ Summer time changes for Morocco (to start late April 2012)
+
+ asia
+ Changes for 2012 for Gaza & the West Bank (Hebron) and Syria
+
+ northamerica
+ Haiti following US/Canada rules for 2012 (and we're assuming,
+ for now anyway, for the future).
+
+
+Release 2012b - 2012-03-02 12:29:15 +0700
+
+ There is just one change to tzcode2012b (compared with 2012a):
+ the Makefile that was accidentally included with 2012a has been
+ replaced with the version that should have been there, which is
+ identical with the previous version (from tzcode2011i).
+
+ There are just two changes in tzdata2012b compared with 2012a.
+
+ Most significantly, summer time in Cuba has been delayed 3 weeks
+ (now starts April 1 rather than March 11). Since Mar 11 (the old start
+ date, as listed in 2012a) is just a little over a week away, this
+ change is urgent.
+
+ Less importantly, an excess tab in one of the changes in zone.tab
+ in 2012a has been removed.
+
+
+Release 2012a - 2012-03-01 18:28:10 +0700
+
+ The changes in tzcode2012a (compared to the previous version, 2011i)
+ are entirely to the README and tz-art.htm and tz-link.htm files, if
+ none of those concern you, you can ignore the code update. The changes
+ reflect the changed addresses for the mailing list and the code and
+ data distribution points & methods (and a link to DateTime::TimeZone::Tzfile
+ has been added to tz-link.htm).
+
+ In tzdata2012a (compared to the previous release, which was 2011n)
+ the major changes are:
+ Chile 2011/2012 and 2012/2013 summer time date adjustments.
+ Falkland Islands onto permanent summer time (we're assuming for the
+ foreseeable future, though 2012 is all we're fairly certain of.)
+ Armenia has abolished Summer Time.
+ Tokelau jumped the International Date Line back last December
+ (just the same as their near neighbour, Samoa).
+ America/Creston is a new zone for a small area of British Columbia
+ There will be a leapsecond 2012-06-30 23:59:60 UTC.
+
+ Other minor changes are:
+ Corrections to 1918 Canadian summer time end dates.
+ Updated URL for UK time zone history (in comments)
+ A few typos in Le Corre's list of free French place names (comments)
+
+
+Release data2011n - 2011-10-30 14:57:54 +0700
+
+ There are three changes of note - most urgently, Cuba (America/Havana)
+ has extended summer time by two weeks, now to end on Nov 13, rather than
+ the (already past) Oct 30. Second, the Pridnestrovian Moldavian Republic
+ (Europe/Tiraspol) decided not to split from the rest of Moldova after
+ all, and consequently that zone has been removed (again) and reinstated
+ in the "backward" file as a link to Europe/Chisinau. And third, the
+ end date for Fiji's summer time this summer was moved forward from the
+ earlier planned Feb 26, to Jan 22.
+
+ Apart from that, Moldova (MD) returns to a single entry in zone.tab
+ (and the incorrect syntax that was in the 2011m version of that file
+ is so fixed - it would have been fixed in a different way had this
+ change not happened - that's the "missing" sccs version id).
+
+
+Release data2011m - 2011-10-24 21:42:16 +0700
+
+ In particular, the typos in comments in the data (2011-11-17 should have
+ been 2011-10-17 as Alan Barrett noted, and spelling of Tiraspol that
+ Tim Parenti noted) have been fixed, and the change for Ukraine has been
+ made in all 4 Ukrainian zones, rather than just Kiev (again, thanks to
+ Tim Parenti, and also Denys Gavrysh)
+
+ In addition, I added Europe/Tiraspol to zone.tab.
+
+ This time, all the files have new version numbers... (including the files
+ otherwise unchanged in 2011m that were changed in 2011l but didn't get new
+ version numbers there...)
+
+
+Release data2011l - 2011-10-10 11:15:43 +0700
+
+ There are just 2 changes that cause different generated tzdata files from
+ zic, to Asia/Hebron and Pacific/Fiji - the possible change for Bahia, Brazil
+ is included, but commented out. Compared with the diff I sent out last week,
+ this version also includes attributions for the sources for the changes
+ (in much the same format as ado used, but the html tags have not been
+ checked, verified, or used in any way at all, so if there are errors there,
+ please let me know.)
+
+
+Release data2011k - 2011-09-20 17:54:03 -0400
+
+ [not summarized]
+
+
+Release data2011j - 2011-09-12 09:22:49 -0400
+
+ (contemporary changes for Samoa; past changes for Kenya, Uganda, and
+ Tanzania); there are also two spelling corrections to comments in
+ the australasia file (with thanks to Christos Zoulas).
+
+
+Release 2011i - 2011-08-29 05:56:32 -0400
+
+ [not summarized]
+
+
+Release data2011h - 2011-06-15 18:41:48 -0400
+
+ Russia and Curaçao changes
+
+
+Release 2011g - 2011-04-25 09:07:22 -0400
+
+ update the rules for Egypt to reflect its abandonment of DST this year
+
+
+Release 2011f - 2011-04-06 17:14:53 -0400
+
+ [not summarized]
+
+
+Release 2011e - 2011-03-31 16:04:38 -0400
+
+ Morocco, Chile, and tz-link changes
+
+
+Release 2011d - 2011-03-14 09:18:01 -0400
+
+ changes that impact present-day timestamps in Cuba, Samoa, and Turkey
+
+
+Release 2011c - 2011-03-07 09:30:09 -0500
+
+ These do affect current timestamps in Chile and Annette Island, Canada.
+
+
+Release 2011b - 2011-02-07 08:44:50 -0500
+
+ [not summarized]
+
+
+Release 2011a - 2011-01-24 10:30:16 -0500
+
+ [not summarized]
+
+
+Release data2010o - 2010-11-01 09:18:23 -0400
+
+ change to the end of DST in Fiji in 2011
+
+
+Release 2010n - 2010-10-25 08:19:17 -0400
+
+ [not summarized]
+
+
+Release 2010m - 2010-09-27 09:24:48 -0400
+
+ Hong Kong, Vostok, and zic.c changes
+
+
+Release 2010l - 2010-08-16 06:57:25 -0400
+
+ [not summarized]
+
+
+Release 2010k - 2010-07-26 10:42:27 -0400
+
+ [not summarized]
+
+
+Release 2010j - 2010-05-10 09:07:48 -0400
+
+ changes for Bahía de Banderas and for version naming
+
+
+Release data2010i - 2010-04-16 18:50:45 -0400
+
+ the end of DST in Morocco on 2010-08-08
+
+
+Release data2010h - 2010-04-05 09:58:56 -0400
+
+ [not summarized]
+
+
+Release data2010g - 2010-03-24 11:14:53 -0400
+
+ [not summarized]
+
+
+Release 2010f - 2010-03-22 09:45:46 -0400
+
+ [not summarized]
+
+
+Release data2010e - 2010-03-08 14:24:27 -0500
+
+ corrects the Dhaka bug found by Danvin Ruangchan
+
+
+Release data2010d - 2010-03-06 07:26:01 -0500
+
+ [not summarized]
+
+
+Release 2010c - 2010-03-01 09:20:58 -0500
+
+ changes including KRE's suggestion for earlier initialization of
+ "goahead" and "goback" structure elements
+
+
+Release code2010a - 2010-02-16 10:40:04 -0500
+
+ [not summarized]
+
+
+Release data2010b - 2010-01-20 12:37:01 -0500
+
+ Mexico changes
+
+
+Release data2010a - 2010-01-18 08:30:04 -0500
+
+ changes to Dhaka
+
+
+Release data2009u - 2009-12-26 08:32:28 -0500
+
+ changes to DST in Bangladesh
+
+
+Release 2009t - 2009-12-21 13:24:27 -0500
+
+ [not summarized]
+
+
+Release data2009s - 2009-11-14 10:26:32 -0500
+
+ (cosmetic) Antarctica change and the DST-in-Fiji-in-2009-and-2010 change
+
+
+Release 2009r - 2009-11-09 10:10:31 -0500
+
+ "antarctica" and "tz-link.htm" changes
+
+
+Release 2009q - 2009-11-02 09:12:40 -0500
+
+ with two corrections as reported by Eric Muller and Philip Newton
+
+
+Release data2009p - 2009-10-23 15:05:27 -0400
+
+ Argentina (including San Luis) changes (with the correction from
+ Mariano Absatz)
+
+
+Release data2009o - 2009-10-14 16:49:38 -0400
+
+ Samoa (commentary only), Pakistan, and Bangladesh changes
+
+
+Release data2009n - 2009-09-22 15:13:38 -0400
+
+ added commentary for Argentina and a change to the end of DST in
+ 2009 in Pakistan
+
+
+Release data2009m - 2009-09-03 10:23:43 -0400
+
+ Samoa and Palestine changes
+
+
+Release data2009l - 2009-08-14 09:13:07 -0400
+
+ Samoa (comments only) and Egypt
+
+
+Release 2009k - 2009-07-20 09:46:08 -0400
+
+ [not summarized]
+
+
+Release data2009j - 2009-06-15 06:43:59 -0400
+
+ Bangladesh change (with a short turnaround since the DST change is
+ impending)
+
+
+Release 2009i - 2009-06-08 09:21:22 -0400
+
+ updating for DST in Bangladesh this year
+
+
+Release 2009h - 2009-05-26 09:19:14 -0400
+
+ [not summarized]
+
+
+Release data2009g - 2009-04-20 16:34:07 -0400
+
+ Cairo
+
+
+Release data2009f - 2009-04-10 11:00:52 -0400
+
+ correct DST in Pakistan
+
+
+Release 2009e - 2009-04-06 09:08:11 -0400
+
+ [not summarized]
+
+
+Release 2009d - 2009-03-23 09:38:12 -0400
+
+ Morocco, Tunisia, Argentina, and American Astronomical Society changes
+
+
+Release data2009c - 2009-03-16 09:47:51 -0400
+
+ change to the start of Cuban DST
+
+
+Release 2009b - 2009-02-09 11:15:22 -0500
+
+ [not summarized]
+
+
+Release 2009a - 2009-01-21 10:09:39 -0500
+
+ [not summarized]
+
+
+Release data2008i - 2008-10-21 12:10:25 -0400
+
+ southamerica and zone.tab files, with Argentina DST rule changes and
+ United States zone reordering and recommenting
+
+
+Release 2008h - 2008-10-13 07:33:56 -0400
+
+ [not summarized]
+
+
+Release 2008g - 2008-10-06 09:03:18 -0400
+
+ Fix a broken HTML anchor and update Brazil's DST transitions;
+ there's also a slight reordering of information in tz-art.htm.
+
+
+Release data2008f - 2008-09-09 22:33:26 -0400
+
+ [not summarized]
+
+
+Release 2008e - 2008-07-28 14:11:17 -0400
+
+ changes by Arthur David Olson and Jesper Nørgaard Welen
+
+
+Release data2008d - 2008-07-07 09:51:38 -0400
+
+ changes by Arthur David Olson, Paul Eggert, and Rodrigo Severo
+
+
+Release data2008c - 2008-05-19 17:48:03 -0400
+
+ Pakistan, Morocco, and Mongolia
+
+
+Release data2008b - 2008-03-24 08:30:59 -0400
+
+ including renaming Asia/Calcutta to Asia/Kolkata, with a backward
+ link provided
+
+
+Release 2008a - 2008-03-08 05:42:16 -0500
+
+ [not summarized]
+
+
+Release 2007k - 2007-12-31 10:25:22 -0500
+
+ most importantly, changes to the "southamerica" file based on
+ Argentina's readoption of daylight saving time
+
+
+Release 2007j - 2007-12-03 09:51:01 -0500
+
+ 1. eliminate the "P" (parameter) macro;
+
+ 2. the "noncontroversial" changes circulated on the time zone
+ mailing list (less the changes to "logwtmp.c");
+
+ 3. eliminate "too many transition" errors when "min" is used in time
+ zone rules;
+
+ 4. changes by Paul Eggert (including updated information for Venezuela).
+
+
+Release data2007i - 2007-10-30 10:28:11 -0400
+
+ changes for Cuba and Syria
+
+
+Release 2007h - 2007-10-01 10:05:51 -0400
+
+ changes by Paul Eggert, as well as an updated link to the ICU
+ project in tz-link.htm
+
+
+Release 2007g - 2007-08-20 10:47:59 -0400
+
+ changes by Paul Eggert
+
+ The "leapseconds" file has been updated to incorporate the most
+ recent International Earth Rotation and Reference Systems Service
+ (IERS) bulletin.
+
+ There's an addition to tz-art.htm regarding the television show "Medium".
+
+
+Release 2007f - 2007-05-07 10:46:46 -0400
+
+ changes by Paul Eggert (including Haiti, Turks and Caicos, and New
+ Zealand)
+
+ changes to zic.c to allow hour values greater than 24 (along with
+ Paul's improved time value overflow checking)
+
+
+Release 2007e - 2007-04-02 10:11:52 -0400
+
+ Syria and Honduras changes by Paul Eggert
+
+ zic.c variable renaming changes by Arthur David Olson
+
+
+Release 2007d - 2007-03-20 08:48:30 -0400
+
+ changes by Paul Eggert
+
+ the elimination of white space at the ends of lines
+
+
+Release 2007c - 2007-02-26 09:09:37 -0500
+
+ changes by Paul Eggert
+
+
+Release 2007b - 2007-02-12 09:34:20 -0500
+
+ Paul Eggert's proposed change to the quotation handling logic in zic.c.
+
+ changes to the commentary in "leapseconds" reflecting the IERS
+ announcement that there is to be no positive leap second at the end
+ of June 2007.
+
+
+Release 2007a - 2007-01-08 12:28:29 -0500
+
+ changes by Paul Eggert
+
+ Derick Rethan's Asmara change
+
+ Oscar van Vlijmen's Easter Island local mean time change
+
+ symbolic link changes
+
+
+Release 2006p - 2006-11-27 08:54:27 -0500
+
+ changes by Paul Eggert
+
+
+Release 2006o - 2006-11-06 09:18:07 -0500
+
+ changes by Paul Eggert
+
+
+Release 2006n - 2006-10-10 11:32:06 -0400
+
+ changes by Paul Eggert
+
+
+Release 2006m - 2006-10-02 15:32:35 -0400
+
+ changes for Uruguay, Palestine, and Egypt by Paul Eggert
+
+ (minimalist) changes to zic.8 to clarify "until" information
+
+
+Release data2006l - 2006-09-18 12:58:11 -0400
+
+ Paul's best-effort work on this coming weekend's Egypt time change
+
+
+Release 2006k - 2006-08-28 12:19:09 -0400
+
+ changes by Paul Eggert
+
+
+Release 2006j - 2006-08-21 09:56:32 -0400
+
+ changes by Paul Eggert
+
+
+Release code2006i - 2006-08-07 12:30:55 -0400
+
+ localtime.c fixes
+
+ Ken Pizzini's conversion script
+
+
+Release code2006h - 2006-07-24 09:19:37 -0400
+
+ adds public domain notices to four files
+
+ includes a fix for transition times being off by a second
+
+ adds a new recording to the "arts" file (information courtesy Colin Bowern)
+
+
+Release 2006g - 2006-05-08 17:18:09 -0400
+
+ northamerica changes by Paul Eggert
+
+
+Release 2006f - 2006-05-01 11:46:00 -0400
+
+ a missing version number problem is fixed (with thanks to Bradley
+ White for catching the problem)
+
+
+Release 2006d - 2006-04-17 14:33:43 -0400
+
+ changes by Paul Eggert
+
+ added new items to tz-arts.htm that were found by Paul
+
+
+Release 2006c - 2006-04-03 10:09:32 -0400
+
+ two sets of data changes by Paul Eggert
+
+ a fencepost error fix in zic.c
+
+ changes to zic.c and the "europe" file to minimize differences
+ between output produced by the old 32-bit zic and the new 64-bit
+ version
+
+
+Release 2006b - 2006-02-20 10:08:18 -0500
+ [tz32code2006b + tz64code2006b + tzdata2006b]
+
+ 64-bit code
+
+ All SCCS IDs were bumped to "8.1" for this release.
+
+
+Release 2006a - 2006-01-30 08:59:31 -0500
+
+ changes by Paul Eggert (in particular, Indiana time zone moves)
+
+ an addition to the zic manual page to describe how special-case
+ transitions are handled
+
+
+Release 2005r - 2005-12-27 09:27:13 -0500
+
+ Canadian changes by Paul Eggert
+
+ They also add "<pre>" directives to time zone data files and reflect
+ changes to warning message logic in "zdump.c" (but with calls to
+ "gettext" kept unbundled at the suggestion of Ken Pizzini).
+
+
+Release 2005q - 2005-12-13 09:17:09 -0500
+
+ Nothing earth-shaking here:
+ 1. Electronic mail addresses have been removed.
+ 2. Casts of the return value of exit have been removed.
+ 3. Casts of the argument of is.* macros have been added.
+ 4. Indentation in one section of zic.c has been fixed.
+ 5. References to dead URLs in the data files have been dealt with.
+
+
+Release 2005p - 2005-12-05 10:30:53 -0500
+
+ "systemv", "tz-link.htm", and "zdump.c" changes
+ (less the casts of arguments to the is* macros)
+
+
+Release 2005o - 2005-11-28 10:55:26 -0500
+
+ Georgia, Cuba, Nicaragua, and Jordan changes by Paul Eggert
+
+ zdump.c lint fixes by Arthur David Olson
+
+
+Release 2005n - 2005-10-03 09:44:09 -0400
+
+ changes by Paul Eggert (both the Uruguay changes and the Kyrgyzstan
+ et al. changes)
+
+
+Release 2005m - 2005-08-29 12:15:40 -0400
+
+ changes by Paul Eggert (with a small tweak to the tz-art change)
+
+ a declaration of an unused variable has been removed from zdump.c
+
+
+Release 2005l - 2005-08-22 12:06:39 -0400
+
+ changes by Paul Eggert
+
+ overflow/underflow checks by Arthur David Olson, minus changes to
+ the "Theory" file about the pending addition of 64-bit data (I grow
+ less confident of the changes being accepted with each passing day,
+ and the changes no longer increase the data files nine-fold--there's
+ less than a doubling in size by my local Sun's reckoning)
+
+
+Release 2005k - 2005-07-14 14:14:24 -0400
+
+ The "leapseconds" file has been edited to reflect the recently
+ announced leap second at the end of 2005.
+
+ I've also deleted electronic mail addresses from the files as an
+ anti-spam measure.
+
+
+Release 2005j - 2005-06-13 14:34:13 -0400
+
+ These reflect changes to limit the length of time zone abbreviations
+ and the characters used in those abbreviations.
+
+ There are also changes to handle POSIX-style "quoted" time zone
+ environment variables.
+
+ The changes were circulated on the time zone mailing list; the only
+ change since then was the removal of a couple of minimum-length of
+ abbreviation checks.
+
+
+Release data2005i - 2005-04-21 15:04:16 -0400
+
+ changes (most importantly to Nicaragua and Haiti) by Paul Eggert
+
+
+Release 2005h - 2005-04-04 11:24:47 -0400
+
+ changes by Paul Eggert
+
+ minor changes to Makefile and zdump.c to produce more useful output
+ when doing a "make typecheck"
+
+
+Release 2005g - 2005-03-14 10:11:21 -0500
+
+ changes by Paul Eggert (a change to current DST rules in Uruguay and
+ an update to a link to time zone software)
+
+
+Release 2005f - 2005-03-01 08:45:32 -0500
+
+ data and documentation changes by Paul Eggert
+
+
+Release 2005e - 2005-02-10 15:59:44 -0500
+
+ [not summarized]
+
+
+Release code2005d - 2005-01-31 09:21:47 -0500
+
+ make zic complain about links to links if the -v flag is used
+
+ have "make public" do more code checking
+
+ add an include to "localtime.c" for the benefit of gcc systems
+
+
+Release 2005c - 2005-01-17 18:36:29 -0500
+
+ get better results when mktime runs on a system where time_t is double
+
+ changes to the data files (most importantly to Paraguay)
+
+
+Release 2005b - 2005-01-10 09:19:54 -0500
+
+ Get localtime and gmtime working on systems with exotic time_t types.
+
+ Update the leap second commentary in the "leapseconds" file.
+
+
+Release 2005a - 2005-01-01 13:13:44 -0500
+
+ [not summarized]
+
+
+Release code2004i - 2004-12-14 13:42:58 -0500
+
+ Deal with systems where time_t is unsigned.
+
+
+Release code2004h - 2004-12-07 11:40:18 -0500
+
+ 64-bit-time_t changes
+
+
+Release 2004g - 2004-11-02 09:06:01 -0500
+
+ update to Cuba (taking effect this weekend)
+
+ other changes by Paul Eggert
+
+ correction of the spelling of Oslo
+
+ changed versions of difftime.c and private.h
+
+
+Release code2004f - 2004-10-21 10:25:22 -0400
+
+ Cope with wide-ranging tm_year values.
+
+
+Release 2004e - 2004-10-11 14:47:21 -0400
+
+ Brazil/Argentina/Israel changes by Paul Eggert
+
+ changes to tz-link.htm by Paul
+
+ one small fix to Makefile
+
+
+Release 2004d - 2004-09-22 08:27:29 -0400
+
+ Avoid overflow problems when TM_YEAR_BASE is added to an integer.
+
+
+Release 2004c - 2004-08-11 12:06:26 -0400
+
+ asctime-related changes
+
+ (variants of) some of the documentation changes suggested by Paul Eggert
+
+
+Release 2004b - 2004-07-19 14:33:35 -0400
+
+ data changes by Paul Eggert - most importantly, updates for Argentina
+
+
+Release 2004a - 2004-05-27 12:00:47 -0400
+
+ changes by Paul Eggert
+
+ Handle DST transitions that occur at the end of a month in some
+ years but at the start of the following month in other years.
+
+ Add a copy of the correspondence that's the basis for claims about
+ DST in the Navajo Nation.
+
+
+Release 2003e - 2003-12-15 09:36:47 -0500
+
+ changes by Arthur David Olson (primarily code changes)
+
+ changes by Paul Eggert (primarily data changes)
+
+ minor changes to "Makefile" and "northamerica" (in the latter case,
+ optimization of the "Toronto" rules)
+
+
+Release 2003d - 2003-10-06 09:34:44 -0400
+
+ changes by Paul Eggert
+
+
+Release 2003c - 2003-09-16 10:47:05 -0400
+
+ Fix bad returns in zic.c's inleap function.
+ Thanks to Bradley White for catching the problem!
+
+
+Release 2003b - 2003-09-16 07:13:44 -0400
+
+ Add a "--version" option (and documentation) to the zic and zdump commands.
+
+ changes to overflow/underflow checking in zic
+
+ a localtime typo fix.
+
+ Update the leapseconds and tz-art.htm files.
+
+
+Release 2003a - 2003-03-24 09:30:54 -0500
+
+ changes by Paul Eggert
+
+ a few additions and modifications to the tz-art.htm file
+
+
+Release 2002d - 2002-10-15 13:12:42 -0400
+
+ changes by Paul Eggert, less the "Britain (UK)" change in iso3166.tab
+
+ There's also a new time zone quote in "tz-art.htm".
+
+
+Release 2002c - 2002-04-04 11:55:20 -0500
+
+ changes by Paul Eggert
+
+ Change zic.c to avoid creating symlinks to files that don't exist.
+
+
+Release 2002b - 2002-01-28 12:56:03 -0500
+
+ [These change notes are for Release 2002a, which was corrupted.
+ 2002b was a corrected version of 2002a.]
+
+ changes by Paul Eggert
+
+ Update the "leapseconds" file to note that there'll be no leap
+ second at the end of June, 2002.
+
+ Change "zic.c" to deal with a problem in handling the "Asia/Bishkek" zone.
+
+ Change to "difftime.c" to avoid sizeof problems.
+
+
+Release 2001d - 2001-10-09 13:31:32 -0400
+
+ changes by Paul Eggert
+
+
+Release 2001c - 2001-06-05 13:59:55 -0400
+
+ changes by Paul Eggert and Andrew Brown
+
+
+Release 2001b - 2001-04-05 16:44:38 -0400
+
+ changes by Paul Eggert (modulo jnorgard's typo fix)
+
+ tz-art.htm has been HTMLified.
+
+
+Release 2001a - 2001-03-13 12:57:44 -0500
+
+ changes by Paul Eggert
+
+ An addition to the "leapseconds" file: comments with the text of the
+ latest IERS leap second notice.
+
+ Trailing white space has been removed from data file lines, and
+ repeated spaces in "Rule Jordan" lines in the "asia" file have been
+ converted to tabs.
+
+
+Release 2000h - 2000-12-14 15:33:38 -0500
+
+ changes by Paul Eggert
+
+ one typo fix in the "art" file
+
+ With providence, this is the last update of the millennium.
+
+
+Release 2000g - 2000-10-10 11:35:22 -0400
+
+ changes by Paul Eggert
+
+ correction of John Mackin's name submitted by Robert Elz
+
+ Garry Shandling's Daylight Saving Time joke (!?!) from the recent
+ Emmy Awards broadcast.
+
+
+Release 2000f - 2000-08-10 09:31:58 -0400
+
+ changes by Paul Eggert
+
+ Added information in "tz-art.htm" on a Seinfeld reference to DST.
+
+ Error checking and messages in the "yearistype" script have been
+ improved.
+
+
+Release 2000e - 2000-07-31 09:27:54 -0400
+
+ data changes by Paul Eggert
+
+ a change to the default value of the defined constant HAVE_STRERROR
+
+ the addition of a Dave Barry quote on DST to the tz-arts file
+
+
+Release 2000d - 2000-04-20 15:43:04 -0400
+
+ changes to the documentation and code of strftime for C99 conformance
+
+ a bug fix for date.c
+
+ These are based on (though modified from) changes by Paul Eggert.
+
+
+Release 2000c - 2000-03-04 10:31:43 -0500
+
+ changes by Paul Eggert
+
+
+Release 2000b - 2000-02-21 12:16:29 -0500
+
+ changes by Paul Eggert and Joseph Myers
+
+ modest tweaks to the tz-art.htm and tz-link.htm files
+
+
+Release 2000a - 2000-01-18 09:21:26 -0500
+
+ changes by Paul Eggert
+
+ The two hypertext documents have also been renamed.
+
+
+Release code1999i-data1999j - 1999-11-15 18:43:22 -0500
+
+ Paul Eggert's changes
+
+ additions to the "zic" manual page and the "Arts.htm" file
+
+
+Release code1999h-data1999i - 1999-11-08 14:55:21 -0500
+
+ [not summarized]
+
+
+Release data1999h - 1999-10-07 03:50:29 -0400
+
+ changes by Paul Eggert to "europe" (most importantly, fixing
+ Lithuania and Estonia)
+
+
+Release 1999g - 1999-09-28 11:06:18 -0400
+
+ data changes by Paul Eggert (most importantly, the change for
+ Lebanon that buys correctness for this coming Sunday)
+
+ The "code" file contains changes to "Makefile" and "checktab.awk" to
+ allow better checking of time zone files before they are published.
+
+
+Release 1999f - 1999-09-23 09:48:14 -0400
+
+ changes by Arthur David Olson and Paul Eggert
+
+
+Release 1999e - 1999-08-17 15:20:54 -0400
+
+ changes circulated by Paul Eggert, although the change to handling
+ of DST-specifying time zone names has been commented out for now
+ (search for "XXX" in "localtime.c" for details). These files also
+ do not make any changes to the start of DST in Brazil.
+
+ In addition to Paul's changes, there are updates to "Arts.htm" and
+ cleanups of URLs.
+
+
+Release 1999d - 1999-03-30 11:31:07 -0500
+
+ changes by Paul Eggert
+
+ The Makefile's "make public" rule has also been changed to do a test
+ compile of each individual time zone data file (which should help
+ avoid problems such as the one we had with Nicosia).
+
+
+Release 1999c - 1999-03-25 09:47:47 -0500
+
+ changes by Paul Eggert, most importantly the change for Chile.
+
+
+Release 1999b - 1999-02-01 17:51:44 -0500
+
+ changes by Paul Eggert
+
+ code changes (suggested by Mani Varadarajan, mani at be.com) for
+ correct handling of symbolic links when building using a relative directory
+
+ code changes to generate correct messages for failed links
+
+ updates to the URLs in Arts.htm
+
+
+Release 1999a - 1999-01-19 16:20:29 -0500
+
+ error message internationalizations and corrections in zic.c and
+ zdump.c (as suggested by Vladimir Michl, vladimir.michl at upol.cz,
+ to whom thanks!)
+
+
+Release code1998h-data1998i - 1998-10-01 09:56:10 -0400
+
+ changes for Brazil, Chile, and Germany
+
+ support for use of "24:00" in the input files for the time zone compiler
+
+
+Release code1998g-data1998h - 1998-09-24 10:50:28 -0400
+
+ changes by Paul Eggert
+
+ correction to a define in the "private.h" file
+
+
+Release data1998g - 1998-08-11 03:28:35 -0000
+ [tzdata1998g.tar.gz is missing!]
+
+ Lithuanian change provided by mgedmin at pub.osf.it
+
+ Move creation of the GMT link with Etc/GMT to "etcetera" (from
+ "backward") to ensure that the GMT file is created even where folks
+ don't want the "backward" links (as suggested by Paul Eggert).
+
+
+Release data1998f - 1998-07-20 13:50:00 -0000
+ [tzdata1998f.tar.gz is missing!]
+
+ Update the "leapseconds" file to include the newly-announced
+ insertion at the end of 1998.
+
+
+Release code1998f - 1998-06-01 10:18:31 -0400
+
+ addition to localtime.c by Guy Harris
+
+
+Release 1998e - 1998-05-28 09:56:26 -0400
+
+ The Makefile is changed to produce zoneinfo-posix rather than
+ zoneinfo/posix, and to produce zoneinfo-leaps rather than
+ zoneinfo/right.
+
+ data changes by Paul Eggert
+
+ changes from Guy Harris to provide asctime_r and ctime_r
+
+ A usno1998 file (substantially identical to usno1997) has been added.
+
+
+Release 1998d - 1998-05-14 11:58:34 -0400
+
+ changes to comments (in particular, elimination of references to CIA maps).
+ "Arts.htm", "WWW.htm", "asia", and "australasia" are the only places
+ where changes occur.
+
+
+Release 1998c - 1998-02-28 12:32:26 -0500
+
+ changes by Paul Eggert (save the "French correction," on which I'll
+ wait for the dust to settle)
+
+ symlink changes
+
+ changes and additions to Arts.htm
+
+
+Release 1998b - 1998-01-17 14:31:51 -0500
+
+ URL cleanups and additions
+
+
+Release 1998a - 1998-01-13 12:37:35 -0500
+
+ changes by Paul Eggert
+
+
+Release code1997i-data1997k - 1997-12-29 09:53:41 -0500
+
+ changes by Paul Eggert, with minor modifications from Arthur David
+ Olson to make the files more browser friendly
+
+
+Release code1997h-data1997j - 1997-12-18 17:47:35 -0500
+
+ minor changes to put "TZif" at the start of each time zone information file
+
+ a rule has also been added to the Makefile so you can
+ make zones
+ to just recompile the zone information files (rather than doing a
+ full "make install" with its other effects).
+
+
+Release data1997i - 1997-10-07 08:45:38 -0400
+
+ changes to Africa by Paul Eggert
+
+
+Release code1997g-data1997h - 1997-09-04 16:56:54 -0400
+
+ corrections for Uruguay (and other locations)
+
+ Arthur David Olson's simple-minded fix allowing mktime to both
+ correctly handle leap seconds and correctly handle tm_sec values
+ upon which arithmetic has been performed.
+
+
+Release code1997f-data1997g - 1997-07-19 13:15:02 -0400
+
+ Paul Eggert's updates
+
+ a small change to a function prototype;
+
+ "Music" has been renamed "Arts.htm", HTMLified, and augmented to
+ include information on Around the World in Eighty Days.
+
+
+Release code1997e-data1997f - 1997-05-03 18:52:34 -0400
+
+ fixes to zic's error handling
+
+ changes inspired by the item circulated on Slovenia
+
+ The description of Web resources has been HTMLified for browsing
+ convenience.
+
+ A new piece of tz-related music has been added to the "Music" file.
+
+
+Release code1997d-data1997e - 1997-03-29 12:48:52 -0500
+
+ Paul Eggert's latest suggestions
+
+
+Release code1997c-data1997d - 1997-03-07 20:37:54 -0500
+
+ changes to "zic.c" to correct performance of the "-s" option
+
+ a new file "usno1997"
+
+
+Release data1997c - 1997-03-04 09:58:18 -0500
+
+ changes in Israel
+
+
+Release 1997b - 1997-02-27 18:34:19 -0500
+
+ The data file incorporates the 1997 leap second.
+
+ The code file incorporates Arthur David Olson's take on the
+ zic/multiprocessor/directory-creation situation.
+
+
+Release 1997a - 1997-01-21 09:11:10 -0500
+
+ Paul Eggert's Antarctica (and other changes)
+
+ Arthur David Olson finessed the "getopt" issue by checking against
+ both -1 and EOF (regardless of POSIX, SunOS 4.1.1's manual says -1
+ is returned while SunOS 5.5's manual says EOF is returned).
+
+
+Release code1996o-data1996n - 1996-12-27 21:42:05 -0500
+
+ Paul Eggert's latest changes
+
+
+Release code1996n - 1996-12-16 09:42:02 -0500
+
+ link snapping fix from Bruce Evans (via Garrett Wollman)
+
+
+Release data1996m - 1996-11-24 02:37:34 -0000
+ [tzdata1996m.tar.gz is missing!]
+
+ Paul Eggert's batch of changes
+
+
+Release code1996m-data1996l - 1996-11-05 14:00:12 -0500
+
+ No functional changes here; the files have simply been changed to
+ make more use of ISO style dates in comments. The names of the above
+ files now include the year in full.
+
+
+Release code96l - 1996-09-08 17:12:20 -0400
+
+ tzcode96k was missing a couple of pieces.
+
+
+Release 96k - 1996-09-08 16:06:22 -0400
+
+ the latest round of changes from Paul Eggert
+
+ the recent Year 2000 material
+
+
+Release code96j - 1996-07-30 13:18:53 -0400
+
+ Set sp->typecnt as suggested by Timothy Patrick Murphy.
+
+
+Release code96i - 1996-07-27 20:11:35 -0400
+
+ Paul's suggested patch for strftime %V week numbers
+
+
+Release data96i - 1996-07-01 18:13:04 -0400
+
+ "northamerica" and "europe" changes by Paul Eggert
+
+
+Release code96h - 1996-06-05 08:02:21 -0400
+
+ fix for handling transitions specified in Universal Time
+
+ Some "public domain" notices have also been added.
+
+
+Release code96g - 1996-05-16 14:00:26 -0400
+
+ fix for the simultaneous-DST-and-zone-change challenge
+
+
+Release data96h - 1996-05-09 17:40:51 -0400
+
+ changes by Paul Eggert
+
+
+Release code96f-data96g - 1996-05-03 03:09:59 -0000
+ [tzcode96f.tar.gz + tzdata96g.tar.gz are both missing!]
+
+ The changes get us some of the way to fixing the problems noted in Paul
+ Eggert's letter yesterday (in addition to a few others). The approach
+ has been to make zic a bit smarter about figuring out what time zone
+ abbreviations apply just after the time specified in the "UNTIL" part
+ of a zone line. Putting the smarts in zic means avoiding having
+ transition times show up in both "Zone" lines and "Rule" lines, which
+ in turn avoids multiple transition time entries in time zone files.
+ (This also makes the zic input files such as "europe" a bit shorter and
+ should ease maintenance.)
+
+
+Release data96f - 1996-04-19 19:20:03 -0000
+ [tzdata96f.tar.gz is missing!]
+
+ The only changes are to the "northamerica" file; the time zone
+ abbreviation for Denver is corrected to MST (and MDT), and the
+ comments for Mexico have been updated.
+
+
+Release data96e - 1996-03-19 17:37:26 -0500
+
+ Proposals by Paul Eggert, in particular the Portugal change that
+ comes into play at the end of this month.
+
+
+Release data96d - 1996-03-18 20:49:39 -0500
+
+ [not summarized]
+
+
+Release code96e - 1996-02-29 15:43:27 -0000
+ [tzcode96e.tar.gz is missing!]
+
+ internationalization changes and the fix to the documentation for strftime
+
+
+Release code96d-data96c - 1996-02-12 11:05:27 -0500
+
+ The "code" file simply updates Bob Kridle's electronic address.
+
+ The "data" file updates rules for Mexico.
+
+
+Release data96b - 1996-01-27 15:44:42 -0500
+
+ Kiribati change
+
+
+Release code96c - 1996-01-16 16:58:15 -0500
+
+ leap-year streamlining and binary-search changes
+
+ fix to newctime.3
+
+
+Release code96b - 1996-01-10 20:42:39 -0500
+
+ fixes and enhancements from Paul Eggert, including code that
+ emulates the behavior of recent versions of the SunOS "date"
+ command.
+
+
+Release 96a - 1996-01-06 09:08:24 -0500
+
+ Israel updates
+
+ fixes to strftime.c for correct ISO 8601 week number generation,
+ plus support for two new formats ('G' and 'g') to give ISO 8601 year
+ numbers (which are not necessarily the same as calendar year numbers)
+
+
+Release code95i-data95m - 1995-12-21 12:46:47 -0500
+
+ The latest revisions from Paul Eggert are included, the usno1995
+ file has been updated, and a new file ("WWW") covering useful URLs
+ has been added.
+
+
+Release code95h-data95l - 1995-12-19 18:10:12 -0500
+
+ A simplification of a macro definition, a change to data for Sudan,
+ and (for last minute shoppers) notes in the "Music" file on the CD
+ "Old Man Time".
+
+
+Release code95g-data95k - 1995-10-30 10:32:47 -0500
+
+ (slightly reformatted) 8-bit-clean proposed patch
+
+ minor patch: US/Eastern -> America/New_York
+
+ snapshot of the USNO's latest data ("usno1995")
+
+ some other minor cleanups
+
+
+Release code95f-data95j - 1995-10-28 21:01:34 -0000
+ [tzcode95f.tar.gz + tzdata95j.tar.gz are both missing!]
+
+ European cleanups
+
+ support for 64-bit time_t's
+
+ optimization in localtime.c
+
+
+Release code95e - 1995-10-13 13:23:57 -0400
+
+ the mktime change to scan from future to past when trying to find time zone
+ offsets
+
+
+Release data95i - 1995-09-26 10:43:26 -0400
+
+ For Canada/Central, guess that the Sun customer's "one week too
+ early" was just a approximation, and the true error is one month
+ too early. This is consistent with the rest of Canada.
+
+
+Release data95h - 1995-09-21 11:26:48 -0400
+
+ latest changes from Paul Eggert
+
+
+Release code95d - 1995-09-14 11:14:45 -0400
+
+ the addition of a "Music" file, which documents four recorded
+ versions of the tune "Save That Time".
+
+
+Release data95g - 1995-09-01 17:21:36 -0400
+
+ "yearistype" correction
+
+
+Release data95f - 1995-08-28 20:46:56 -0400
+
+ Paul Eggert's change to the australasia file
+
+
+Release data95e - 1995-07-08 18:02:34 -0400
+
+ The only change is a leap second at the end of this year.
+ Thanks to Bradley White for forwarding news on the leap second.
+
+
+Release data95d - 1995-07-03 13:26:22 -0400
+
+ Paul Eggert's changes
+
+
+Release data95c - 1995-07-02 19:19:28 -0400
+
+ changes to "asia", "backward", "europe", and "southamerica"
+ (read: northamericacentrics need not apply)
+
+
+Release code95c - 1995-03-13 14:00:46 -0500
+
+ one-line fix for sign extension problems in detzcode
+
+
+Release 95b - 1995-03-04 11:22:38 -0500
+
+ Minor changes in both:
+
+ The "code" file contains a workaround for the lack of "unistd.h" in
+ Microsoft C++ version 7.
+
+ The "data" file contains a fixed "Link" for America/Shiprock.
+
+
+Release 94h - 1994-12-10 12:51:14 -0500
+
+ The files:
+
+ * incorporate the changes to "zdump" and "date" to make changes to
+ the "TZ" environment variable permanent;
+
+ * incorporate the table changes by Paul Eggert;
+
+ * include (and document) support for universal time specifications in
+ data files - but do not (yet) include use of this feature in the
+ data files.
+
+ Think of this as "TZ Classic" - the software has been set up not to break if
+ universal time shows up in its input, and data entries have been
+ left as is so as not to break existing implementations.
+
+
+Release data94f - 1994-08-20 12:56:09 -0400
+
+ (with thanks!) the latest data updates from Paul Eggert
+
+
+Release data94e - 1994-06-04 13:13:53 -0400
+
+ [not summarized]
+
+
+Release code94g - 1994-05-05 12:14:07 -0400
+
+ fix missing "optind.c" and a reference to it in the Makefile
+
+
+Release code94f - 1994-05-05 13:00:33 -0000
+ [tzcode94f.tar.gz is missing!]
+
+ changes to avoid overflow in difftime, as well as changes to cope
+ with the 52/53 challenge in strftime
+
+
+Release code94e - 1994-03-30 23:32:59 -0500
+
+ change for the benefit of PCTS
+
+
+Release 94d - 1994-02-24 15:42:25 -0500
+
+ Avoid clashes with POSIX semantics for zones such as GMT+4.
+
+ Some other very minor housekeeping is also present.
+
+
+Release code94c - 1994-02-10 08:52:40 -0500
+
+ Fix bug where mkdirs was broken unless you compile with
+ -fwritable-strings (which is generally losing to do).
+
+
+Release 94b - 1994-02-07 10:04:33 -0500
+
+ work by Paul Eggert who notes:
+
+ I found another book of time zone histories by E W Whitman; it's not
+ as extensive as Shanks but has a few goodies of its own. I used it
+ to update the tables. I also fixed some more as a result of
+ correspondence with Adam David and Peter Ilieve, and move some stray
+ links from 'europe' to 'backward'. I corrected some scanning errors
+ in usno1989.
+
+ As far as the code goes, I fixed zic to allow years in the range
+ INT_MIN to INT_MAX; this fixed a few boundary conditions around 1900.
+ And I cleaned up the zic documentation a little bit.
+
+
+Release data94a - 1994-02-03 08:58:54 -0500
+
+ It simply incorporates the recently announced leap second into the
+ "leapseconds" file.
+
+
+Release 93g - 1993-11-22 17:28:27 -0500
+
+ Paul Eggert has provided a good deal of historic information (based
+ on Shanks), and there are some code changes to deal with the buglets
+ that crawled out in dealing with the new information.
+
+
+Release 93f - 1993-10-15 12:27:46 -0400
+
+ Paul Eggert's changes
+
+
+Release 93e - 1993-09-05 21:21:44 -0400
+
+ This has updated data for Israel, England, and Kwajalein. There's
+ also an update to "zdump" to cope with Kwajalein's 24-hour jump.
+ Thanks to Paul Eggert and Peter Ilieve for the changes.
+
+
+Release 93d - 1993-06-17 23:34:17 -0400
+
+ new fix and new data on Israel
+
+
+Release 93c - 1993-06-06 19:31:55 -0400
+
+ [not summarized]
+
+
+Release 93b - 1993-02-02 14:53:58 -0500
+
+ updated "leapseconds" file
+
+
+Release 93 - 1993-01-08 07:01:06 -0500
+
+ At kre's suggestion, the package has been split in two - a code piece
+ (which also includes documentation) that's only of use to folks who
+ want to recompile things and a data piece useful to anyone who can
+ run "zic".
+
+ The new version has a few changes to the data files, a few
+ portability changes, and an off-by-one fix (with thanks to
+ Tom Karzes at deshaw.com for providing a description and a
+ solution).
+
+
+Release 92c - 1992-11-21 17:35:36 -0000
+ [tz92c.tar.Z is missing!]
+
+ The fallout from the latest round of DST transitions.
+
+ There are changes for Portugal, Saskatchewan, and "Pacific-New";
+ there's also a change to "zic.c" that makes it portable to more systems.
+
+
+Release 92 - 1992-04-25 18:17:03 -0000
+ [tz92.tar.Z is missing!]
+
+ By popular demand (well, at any rate, following a request by kre at munnari)
+
+
+The 1989 update of the time zone package featured:
+
+ * POSIXization (including interpretation of POSIX-style TZ environment
+ variables, provided by Guy Harris),
+ * ANSIfication (including versions of "mktime" and "difftime"),
+ * SVIDulation (an "altzone" variable)
+ * MACHination (the "gtime" function)
+ * corrections to some time zone data (including corrections to the rules
+ for Great Britain and New Zealand)
+ * reference data from the United States Naval Observatory for folks who
+ want to do additional time zones
+ * and the 1989 data for Saudi Arabia.
+
+ (Since this code will be treated as "part of the implementation" in some
+ places and as "part of the application" in others, there's no good way to
+ name functions, such as timegm, that are not part of the proposed ANSI C
+ standard; such functions have kept their old, underscore-free names in this
+ update.)
+
+ And the "dysize" function has disappeared; it was present to allow
+ compilation of the "date" command on old BSD systems, and a version of "date"
+ is now provided in the package. The "date" command is not created when you
+ "make all" since it may lack options provided by the version distributed with
+ your operating system, or may not interact with the system in the same way
+ the native version does.
+
+ Since POSIX frowns on correct leap second handling, the default behavior of
+ the "zic" command (in the absence of a "-L" option) has been changed to omit
+ leap second information from its output files.
+
+
+-----
+Notes
+
+This file contains copies of the part of each release announcement
+that talks about the changes in that release. The text has been
+adapted and reformatted for the purposes of this file.
+
+Traditionally a release R consists of a pair of tarball files,
+tzcodeR.tar.gz and tzdataR.tar.gz. However, some releases (e.g.,
+code2010a, data2012c) consist of just one or the other tarball, and a
+few (e.g., code2012c-data2012d) have tarballs with mixed version
+numbers. Recent releases also come in an experimental format
+consisting of a single tarball tzdb-R.tar.lz with extra data.
+
+Release timestamps are taken from the release's commit (for newer,
+Git-based releases), from the newest file in the tarball (for older
+releases, where this info is available) or from the email announcing
+the release (if all else fails; these are marked with a time zone of
+-0000 and an "is missing!" comment).
+
+Earlier versions of the code and data were not announced on the tz
+list and are not summarized here.
+
+This file is in the public domain.
+
+Local Variables:
+coding: utf-8
+End:
diff --git a/README b/README
new file mode 100644
index 000000000000..ab8e47b63efb
--- /dev/null
+++ b/README
@@ -0,0 +1,52 @@
+README for the tz distribution
+
+"What time is it?" -- Richard Deacon as The King
+"Any time you want it to be." -- Frank Baxter as The Scientist
+ (from the Bell System film "About Time")
+
+The Time Zone Database (often called tz or zoneinfo) contains code and
+data that represent the history of local time for many representative
+locations around the globe. It is updated periodically to reflect
+changes made by political bodies to time zone boundaries, UTC offsets,
+and daylight-saving rules.
+
+See <https://www.iana.org/time-zones/repository/tz-link.html> or the
+file tz-link.html for how to acquire the code and data. Once acquired,
+read the comments in the file 'Makefile' and make any changes needed
+to make things right for your system, especially if you are using some
+platform other than GNU/Linux. Then run the following commands,
+substituting your desired installation directory for "$HOME/tzdir":
+
+ make TOPDIR=$HOME/tzdir install
+ $HOME/tzdir/usr/bin/zdump -v America/Los_Angeles
+
+Historical local time information has been included here to:
+
+* provide a compendium of data about the history of civil time
+ that is useful even if not 100% accurate;
+
+* give an idea of the variety of local time rules that have
+ existed in the past and thus an idea of the variety that may be
+ expected in the future;
+
+* provide a test of the generality of the local time rule description
+ system.
+
+The information in the time zone data files is by no means authoritative;
+fixes and enhancements are welcome. Please see the file CONTRIBUTING
+for details.
+
+Thanks to these Time Zone Caballeros who've made major contributions to the
+time conversion package: Keith Bostic; Bob Devine; Paul Eggert; Robert Elz;
+Guy Harris; Mark Horton; John Mackin; and Bradley White. Thanks also to
+Michael Bloom, Art Neilson, Stephen Prince, John Sovereign, and Frank Wales
+for testing work, and to Gwillim Law for checking local mean time data.
+Thanks in particular to Arthur David Olson, the project's founder and first
+maintainer, to whom the time zone community owes the greatest debt of all.
+None of them are responsible for remaining errors.
+
+-----
+
+This file is in the public domain, so clarified as of 2009-05-17 by
+Arthur David Olson. The other files in this distribution are either
+public domain or BSD licensed; see the file LICENSE for details.
diff --git a/asctime.c b/asctime.c
new file mode 100644
index 000000000000..56c54b383f68
--- /dev/null
+++ b/asctime.c
@@ -0,0 +1,122 @@
+/* asctime and asctime_r a la POSIX and ISO C, except pad years before 1000. */
+
+/*
+** This file is in the public domain, so clarified as of
+** 1996-06-05 by Arthur David Olson.
+*/
+
+/*
+** Avoid the temptation to punt entirely to strftime;
+** the output of strftime is supposed to be locale specific
+** whereas the output of asctime is supposed to be constant.
+*/
+
+/*LINTLIBRARY*/
+
+#include "private.h"
+#include <stdio.h>
+
+/*
+** Some systems only handle "%.2d"; others only handle "%02d";
+** "%02.2d" makes (most) everybody happy.
+** At least some versions of gcc warn about the %02.2d;
+** we conditionalize below to avoid the warning.
+*/
+/*
+** 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.
+** The ISO C and POSIX standards prohibit padding the year,
+** but many implementations pad anyway; most likely the standards are buggy.
+*/
+#ifdef __GNUC__
+#define ASCTIME_FMT "%s %s%3d %2.2d:%2.2d:%2.2d %-4s\n"
+#else /* !defined __GNUC__ */
+#define ASCTIME_FMT "%s %s%3d %02.2d:%02.2d:%02.2d %-4s\n"
+#endif /* !defined __GNUC__ */
+/*
+** 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).
+*/
+#ifdef __GNUC__
+#define ASCTIME_FMT_B "%s %s%3d %2.2d:%2.2d:%2.2d %s\n"
+#else /* !defined __GNUC__ */
+#define ASCTIME_FMT_B "%s %s%3d %02.2d:%02.2d:%02.2d %s\n"
+#endif /* !defined __GNUC__ */
+
+#define STD_ASCTIME_BUF_SIZE 26
+/*
+** Big enough for something such as
+** ??? ???-2147483648 -2147483648:-2147483648:-2147483648 -2147483648\n
+** (two three-character abbreviations, five strings denoting integers,
+** seven explicit spaces, two explicit colons, a newline,
+** and a trailing NUL byte).
+** The values above are for systems where an int is 32 bits and are provided
+** as an example; the define below calculates the maximum for the system at
+** hand.
+*/
+#define MAX_ASCTIME_BUF_SIZE (2*3+5*INT_STRLEN_MAXIMUM(int)+7+2+1+1)
+
+static char buf_asctime[MAX_ASCTIME_BUF_SIZE];
+
+char *
+asctime_r(register const struct tm *timeptr, char *buf)
+{
+ static const char wday_name[][4] = {
+ "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
+ };
+ static const char mon_name[][4] = {
+ "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+ "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
+ };
+ register const char * wn;
+ register const char * mn;
+ char year[INT_STRLEN_MAXIMUM(int) + 2];
+ char result[MAX_ASCTIME_BUF_SIZE];
+
+ if (timeptr == NULL) {
+ errno = EINVAL;
+ return strcpy(buf, "??? ??? ?? ??:??:?? ????\n");
+ }
+ if (timeptr->tm_wday < 0 || timeptr->tm_wday >= DAYSPERWEEK)
+ wn = "???";
+ else wn = wday_name[timeptr->tm_wday];
+ 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
+ ** when computing timeptr->tm_year + TM_YEAR_BASE.
+ ** Assume that strftime is unaffected by other out-of-range members
+ ** (e.g., timeptr->tm_mday) when processing "%Y".
+ */
+ strftime(year, sizeof year, "%Y", timeptr);
+ /*
+ ** We avoid using snprintf since it's not available on all systems.
+ */
+ sprintf(result,
+ ((strlen(year) <= 4) ? ASCTIME_FMT : ASCTIME_FMT_B),
+ wn, mn,
+ timeptr->tm_mday, timeptr->tm_hour,
+ timeptr->tm_min, timeptr->tm_sec,
+ year);
+ if (strlen(result) < STD_ASCTIME_BUF_SIZE || buf == buf_asctime)
+ return strcpy(buf, result);
+ else {
+ errno = EOVERFLOW;
+ return NULL;
+ }
+}
+
+char *
+asctime(register const struct tm *timeptr)
+{
+ return asctime_r(timeptr, buf_asctime);
+}
diff --git a/calendars b/calendars
new file mode 100644
index 000000000000..8bc70626eb5a
--- /dev/null
+++ b/calendars
@@ -0,0 +1,173 @@
+----- Calendrical issues -----
+
+As mentioned in Theory.html, although calendrical issues are out of
+scope for tzdb, they indicate the sort of problems that we would run
+into if we extended tzdb further into the past. The following
+information and sources go beyond Theory.html's brief discussion.
+They sometimes disagree.
+
+
+France
+
+Gregorian calendar adopted 1582-12-20.
+French Revolutionary calendar used 1793-11-24 through 1805-12-31,
+and (in Paris only) 1871-05-06 through 1871-05-23.
+
+
+Russia
+
+From Chris Carrier (1996-12-02):
+On 1929-10-01 the Soviet Union instituted an "Eternal Calendar"
+with 30-day months plus 5 holidays, with a 5-day week.
+On 1931-12-01 it changed to a 6-day week; in 1934 it reverted to the
+Gregorian calendar while retaining the 6-day week; on 1940-06-27 it
+reverted to the 7-day week. With the 6-day week the usual days
+off were the 6th, 12th, 18th, 24th and 30th of the month.
+(Source: Evitiar Zerubavel, _The Seven Day Circle_)
+
+
+Mark Brader reported a similar story in "The Book of Calendars", edited
+by Frank Parise (1982, Facts on File, ISBN 0-8719-6467-8), page 377. But:
+
+From: Petteri Sulonen (via Usenet)
+Date: 14 Jan 1999 00:00:00 GMT
+...
+
+If your source is correct, how come documents between 1929 and 1940 were
+still dated using the conventional, Gregorian calendar?
+
+I can post a scan of a document dated December 1, 1934, signed by
+Yenukidze, the secretary, on behalf of Kalinin, the President of the
+Executive Committee of the Supreme Soviet, if you like.
+
+
+
+Sweden (and Finland)
+
+From: Mark Brader
+Subject: Re: Gregorian reform - a part of locale?
+<news:1996Jul6.012937.29190@sq.com>
+Date: 1996-07-06
+
+In 1700, Denmark made the transition from Julian to Gregorian. Sweden
+decided to *start* a transition in 1700 as well, but rather than have one of
+those unsightly calendar gaps :-), they simply decreed that the next leap
+year after 1696 would be in 1744 - putting the whole country on a calendar
+different from both Julian and Gregorian for a period of 40 years.
+
+However, in 1704 something went wrong and the plan was not carried through;
+they did, after all, have a leap year that year. And one in 1708. In 1712
+they gave it up and went back to Julian, putting 30 days in February that
+year!...
+
+Then in 1753, Sweden made the transition to Gregorian in the usual manner,
+getting there only 13 years behind the original schedule.
+
+(A previous posting of this story was challenged, and Swedish readers
+produced the following references to support it: "Tideräkning och historia"
+by Natanael Beckman (1924) and "Tid, en bok om tideräkning och
+kalenderväsen" by Lars-Olof Lodén (1968).
+
+
+Grotefend's data
+
+From: "Michael Palmer" [with one obvious typo fixed]
+Subject: Re: Gregorian Calendar (was Re: Another FHC related question
+Newsgroups: soc.genealogy.german
+Date: Tue, 9 Feb 1999 02:32:48 -800
+...
+
+The following is a(n incomplete) listing, arranged chronologically, of
+European states, with the date they converted from the Julian to the
+Gregorian calendar:
+
+04/15 Oct 1582 - Italy (with exceptions), Spain, Portugal, Poland (Roman
+ Catholics and Danzig only)
+09/20 Dec 1582 - France, Lorraine
+
+21 Dec 1582/
+ 01 Jan 1583 - Holland, Brabant, Flanders, Hennegau
+10/21 Feb 1583 - bishopric of Liege (Lüttich)
+13/24 Feb 1583 - bishopric of Augsburg
+04/15 Oct 1583 - electorate of Trier
+05/16 Oct 1583 - Bavaria, bishoprics of Freising, Eichstedt, Regensburg,
+ Salzburg, Brixen
+13/24 Oct 1583 - Austrian Oberelsaß and Breisgau
+20/31 Oct 1583 - bishopric of Basel
+02/13 Nov 1583 - duchy of Jülich-Berg
+02/13 Nov 1583 - electorate and city of Köln
+04/15 Nov 1583 - bishopric of Würzburg
+11/22 Nov 1583 - electorate of Mainz
+16/27 Nov 1583 - bishopric of Strassburg and the margraviate of Baden
+17/28 Nov 1583 - bishopric of Münster and duchy of Cleve
+14/25 Dec 1583 - Steiermark
+
+06/17 Jan 1584 - Austria and Bohemia
+11/22 Jan 1584 - Lucerne, Uri, Schwyz, Zug, Freiburg, Solothurn
+12/23 Jan 1584 - Silesia and the Lausitz
+22 Jan/
+ 02 Feb 1584 - Hungary (legally on 21 Oct 1587)
+ Jun 1584 - Unterwalden
+01/12 Jul 1584 - duchy of Westfalen
+
+16/27 Jun 1585 - bishopric of Paderborn
+
+14/25 Dec 1590 - Transylvania
+
+22 Aug/
+ 02 Sep 1612 - duchy of Prussia
+
+13/24 Dec 1614 - Pfalz-Neuburg
+
+ 1617 - duchy of Kurland (reverted to the Julian calendar in
+ 1796)
+
+ 1624 - bishopric of Osnabrück
+
+ 1630 - bishopric of Minden
+
+15/26 Mar 1631 - bishopric of Hildesheim
+
+ 1655 - Kanton Wallis
+
+05/16 Feb 1682 - city of Strassburg
+
+18 Feb/
+ 01 Mar 1700 - Protestant Germany (including Swedish possessions in
+ Germany), Denmark, Norway
+30 Jun/
+ 12 Jul 1700 - Gelderland, Zutphen
+10 Nov/
+ 12 Dec 1700 - Utrecht, Overijssel
+
+31 Dec 1700/
+ 12 Jan 1701 - Friesland, Groningen, Zürich, Bern, Basel, Geneva,
+ Turgau, and Schaffhausen
+
+ 1724 - Glarus, Appenzell, and the city of St. Gallen
+
+01 Jan 1750 - Pisa and Florence
+
+02/14 Sep 1752 - Great Britain
+
+17 Feb/
+ 01 Mar 1753 - Sweden
+
+1760-1812 - Graubünden
+
+The Russian empire (including Finland and the Baltic states) did not
+convert to the Gregorian calendar until the Soviet revolution of 1917.
+
+Source: H. Grotefend, _Taschenbuch der Zeitrechnung des deutschen
+Mittelalters und der Neuzeit_, herausgegeben von Dr. O. Grotefend
+(Hannover: Hahnsche Buchhandlung, 1941), pp. 26-28.
+
+-----
+
+This file is in the public domain, so clarified as of 2009-05-17 by
+Arthur David Olson.
+
+-----
+Local Variables:
+coding: utf-8
+End:
diff --git a/date.1 b/date.1
new file mode 100644
index 000000000000..28dc1d7c08a4
--- /dev/null
+++ b/date.1
@@ -0,0 +1,165 @@
+.TH DATE 1
+.SH NAME
+date \- show and set date and time
+.SH SYNOPSIS
+.if n .nh
+.if n .na
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.B date
+[
+.B \*-u
+] [
+.B \*-c
+] [
+.B \*-r
+.I seconds
+] [
+.BI + format
+] [
+\fR[\fIyyyy\fR]\fImmddhhmm\fR[\fIyy\fR][\fB.\fIss\fR]
+]
+.SH DESCRIPTION
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+.I Date
+without arguments writes the date and time to the standard output in
+the form
+.ce 1
+Wed Mar 8 14:54:40 EST 1989
+.br
+with
+.B EST
+replaced by the local time zone's abbreviation
+(or by the abbreviation for the time zone specified in the
+.B TZ
+environment variable if set).
+The exact output format depends on the locale.
+.PP
+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.
+In the format, when a percent sign (\c
+.q "\fB%\fP"
+appears,
+it and the character after it are not output,
+but rather identify part of the date or time
+to be output in a particular way
+(or identify a special character to output):
+.nf
+.sp
+.if t .in +.5i
+.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
+Use Universal Time when setting and showing the date and time.
+.TP
+.BI "\*-r " seconds
+Output the date that corresponds to
+.I seconds
+past the epoch of 1970-01-01 00:00:00 UTC, where
+.I seconds
+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
+/etc/localtime local time zone file
+.br
+/usr/lib/locale/\f2L\fP/LC_TIME description of time locale \f2L\fP
+.br
+/usr/share/zoneinfo time zone information directory
+.br
+/usr/share/zoneinfo/posixrules used with POSIX-style TZ's
+.br
+/usr/share/zoneinfo/GMT for UTC leap seconds
+.sp
+If
+.B /usr/share/zoneinfo/GMT
+is absent,
+UTC leap seconds are loaded from
+.BR /usr/share/zoneinfo/posixrules .
+.\" This file is in the public domain, so clarified as of
+.\" 2009-05-17 by Arthur David Olson.
diff --git a/date.1.txt b/date.1.txt
new file mode 100644
index 000000000000..de500a347081
--- /dev/null
+++ b/date.1.txt
@@ -0,0 +1,107 @@
+DATE(1) General Commands Manual DATE(1)
+
+NAME
+ date - show and set date and time
+
+SYNOPSIS
+ date [ -u ] [ -c ] [ -r seconds ] [ +format ] [ [yyyy]mmddhhmm[yy][.ss]
+ ]
+
+DESCRIPTION
+ Date without arguments writes the date and time to the standard output
+ in the form
+ Wed Mar 8 14:54:40 EST 1989
+ with EST replaced by the local time zone's abbreviation (or by the
+ abbreviation for the time zone specified in the TZ environment variable
+ if set). The exact output format depends on the locale.
+
+ If a command-line argument starts with a plus sign ("+"), the rest of
+ the argument is used as a format that controls what appears in the
+ output. In the format, when a percent sign ("%" appears, it and the
+ character after it are not output, but rather identify part of the date
+ or time to be output in a particular way (or identify a special
+ character to output):
+
+ 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*
+ * The exact output depends on the locale.
+
+ 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.
+
+ In Sunday-based week numbering, the first Sunday of the year begins
+ week 1; days preceding it are part of "week 0". In Monday-based week
+ numbering, the first Monday of the year begins week 1.
+
+ To set the date, use a command line argument with one of the following
+ forms:
+ 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 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.
+
+ These options are available:
+
+ -u or -c
+ Use Universal Time when setting and showing the date and time.
+
+ -r seconds
+ Output the date that corresponds to seconds past the epoch of
+ 1970-01-01 00:00:00 UTC, where seconds should be an integer,
+ either decimal, octal (leading 0), or hexadecimal (leading 0x),
+ preceded by an optional sign.
+
+FILES
+ /etc/localtime local time zone file
+ /usr/lib/locale/L/LC_TIME description of time locale L
+ /usr/share/zoneinfo time zone information directory
+ /usr/share/zoneinfo/posixrules used with POSIX-style TZ's
+ /usr/share/zoneinfo/GMT for UTC leap seconds
+
+ If /usr/share/zoneinfo/GMT is absent, UTC leap seconds are loaded from
+ /usr/share/zoneinfo/posixrules.
+
+ DATE(1)
diff --git a/date.c b/date.c
new file mode 100644
index 000000000000..2cc533fdd4d2
--- /dev/null
+++ b/date.c
@@ -0,0 +1,237 @@
+/* Display or set the current time and date. */
+
+/* Copyright 1985, 1987, 1988 The Regents of the University of California.
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+ 1. Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+ 3. Neither the name of the University nor the names of its contributors
+ may be used to endorse or promote products derived from this software
+ without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
+ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ SUCH DAMAGE. */
+
+#include "private.h"
+#include <locale.h>
+#include <stdio.h>
+
+/*
+** The two things date knows about time are. . .
+*/
+
+#ifndef TM_YEAR_BASE
+#define TM_YEAR_BASE 1900
+#endif /* !defined TM_YEAR_BASE */
+
+#ifndef SECSPERMIN
+#define SECSPERMIN 60
+#endif /* !defined SECSPERMIN */
+
+#if !HAVE_POSIX_DECLS
+extern char * optarg;
+extern int optind;
+#endif
+
+static int retval = EXIT_SUCCESS;
+
+static void display(const char *, time_t);
+static void dogmt(void);
+static void errensure(void);
+static void timeout(FILE *, const char *, const struct tm *);
+static _Noreturn void usage(void);
+
+int
+main(const int argc, char *argv[])
+{
+ register const char * format;
+ register const char * cp;
+ register int ch;
+ register bool rflag = false;
+ time_t t;
+ intmax_t secs;
+ char * endarg;
+
+#ifdef LC_ALL
+ setlocale(LC_ALL, "");
+#endif /* defined(LC_ALL) */
+#if HAVE_GETTEXT
+#ifdef TZ_DOMAINDIR
+ bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
+#endif /* defined(TEXTDOMAINDIR) */
+ textdomain(TZ_DOMAIN);
+#endif /* HAVE_GETTEXT */
+ t = time(NULL);
+ format = NULL;
+ while ((ch = getopt(argc, argv, "ucr:")) != EOF && ch != -1) {
+ switch (ch) {
+ default:
+ usage();
+ case 'u': /* do it in UT */
+ case 'c':
+ dogmt();
+ break;
+ case 'r': /* seconds since 1970 */
+ if (rflag) {
+ fprintf(stderr,
+ _("date: error: multiple -r's used"));
+ usage();
+ }
+ rflag = true;
+ errno = 0;
+ secs = strtoimax (optarg, &endarg, 0);
+ if (*endarg || optarg == endarg)
+ errno = EINVAL;
+ else if (! (TIME_T_MIN <= secs && secs <= TIME_T_MAX))
+ errno = ERANGE;
+ if (errno) {
+ perror(optarg);
+ errensure();
+ exit(retval);
+ }
+ t = secs;
+ break;
+ }
+ }
+ while (optind < argc) {
+ cp = argv[optind++];
+ if (*cp == '+')
+ if (format == NULL)
+ format = cp + 1;
+ else {
+ fprintf(stderr,
+_("date: error: multiple formats in command line\n"));
+ usage();
+ }
+ else {
+ fprintf(stderr, _("date: unknown operand: %s\n"), cp);
+ usage();
+ }
+ }
+
+ display(format, t);
+ return retval;
+}
+
+static void
+dogmt(void)
+{
+ static char ** fakeenv;
+
+ if (fakeenv == NULL) {
+ register int from;
+ register int to;
+ register int n;
+ static char tzegmt0[] = "TZ=GMT0";
+
+ for (n = 0; environ[n] != NULL; ++n)
+ continue;
+ fakeenv = malloc((n + 2) * sizeof *fakeenv);
+ if (fakeenv == NULL) {
+ perror(_("Memory exhausted"));
+ errensure();
+ exit(retval);
+ }
+ to = 0;
+ fakeenv[to++] = tzegmt0;
+ for (from = 1; environ[from] != NULL; ++from)
+ if (strncmp(environ[from], "TZ=", 3) != 0)
+ fakeenv[to++] = environ[from];
+ fakeenv[to] = NULL;
+ environ = fakeenv;
+ }
+}
+
+static void
+errensure(void)
+{
+ if (retval == EXIT_SUCCESS)
+ retval = EXIT_FAILURE;
+}
+
+static void
+usage(void)
+{
+ fprintf(stderr,
+ _("date: usage: date [-u] [-c] [-r seconds]"
+ " [+format]\n"));
+ errensure();
+ exit(retval);
+}
+
+static void
+display(char const *format, time_t now)
+{
+ struct tm *tmp;
+
+ tmp = localtime(&now);
+ if (!tmp) {
+ fprintf(stderr,
+ _("date: error: time out of range\n"));
+ errensure();
+ return;
+ }
+ timeout(stdout, format ? format : "%+", tmp);
+ putchar('\n');
+ fflush(stdout);
+ fflush(stderr);
+ if (ferror(stdout) || ferror(stderr)) {
+ fprintf(stderr,
+ _("date: error: couldn't write results\n"));
+ errensure();
+ }
+}
+
+#define INCR 1024
+
+static void
+timeout(FILE *fp, char const *format, struct tm const *tmp)
+{
+ char * cp;
+ size_t result;
+ size_t size;
+ struct tm tm;
+
+ if (*format == '\0')
+ return;
+ if (!tmp) {
+ fprintf(stderr, _("date: error: time out of range\n"));
+ errensure();
+ return;
+ }
+ tm = *tmp;
+ tmp = &tm;
+ size = INCR;
+ cp = malloc(size);
+ for ( ; ; ) {
+ if (cp == NULL) {
+ fprintf(stderr,
+ _("date: error: can't get memory\n"));
+ errensure();
+ exit(retval);
+ }
+ cp[0] = '\1';
+ result = strftime(cp, size, format, tmp);
+ if (result != 0 || cp[0] == '\0')
+ break;
+ size += INCR;
+ cp = realloc(cp, size);
+ }
+ fwrite(cp, 1, result, fp);
+ free(cp);
+}
diff --git a/difftime.c b/difftime.c
new file mode 100644
index 000000000000..856234a90d0b
--- /dev/null
+++ b/difftime.c
@@ -0,0 +1,58 @@
+/*
+** This file is in the public domain, so clarified as of
+** 1996-06-05 by Arthur David Olson.
+*/
+
+/*LINTLIBRARY*/
+
+#include "private.h" /* for time_t and TYPE_SIGNED */
+
+/* Return -X as a double. Using this avoids casting to 'double'. */
+static double
+dminus(double x)
+{
+ return -x;
+}
+
+double
+difftime(time_t time1, time_t time0)
+{
+ /*
+ ** If double is large enough, simply convert and subtract
+ ** (assuming that the larger type has more precision).
+ */
+ if (sizeof (time_t) < sizeof (double)) {
+ double t1 = time1, t0 = time0;
+ return t1 - t0;
+ }
+
+ /*
+ ** The difference of two unsigned values can't overflow
+ ** if the minuend is greater than or equal to the subtrahend.
+ */
+ if (!TYPE_SIGNED(time_t))
+ return time0 <= time1 ? time1 - time0 : dminus(time0 - time1);
+
+ /* Use uintmax_t if wide enough. */
+ if (sizeof (time_t) <= sizeof (uintmax_t)) {
+ uintmax_t t1 = time1, t0 = time0;
+ return time0 <= time1 ? t1 - t0 : dminus(t0 - t1);
+ }
+
+ /*
+ ** Handle cases where both time1 and time0 have the same sign
+ ** (meaning that their difference cannot overflow).
+ */
+ if ((time1 < 0) == (time0 < 0))
+ return time1 - time0;
+
+ /*
+ ** The values have opposite signs and uintmax_t is too narrow.
+ ** This suffers from double rounding; attempt to lessen that
+ ** by using long double temporaries.
+ */
+ {
+ long double t1 = time1, t0 = time0;
+ return t1 - t0;
+ }
+}
diff --git a/localtime.c b/localtime.c
new file mode 100644
index 000000000000..5b5a5b131b36
--- /dev/null
+++ b/localtime.c
@@ -0,0 +1,2342 @@
+/*
+** This file is in the public domain, so clarified as of
+** 1996-06-05 by Arthur David Olson.
+*/
+
+/*
+** Leap second handling from Bradley White.
+** POSIX-style TZ environment variable handling from Guy Harris.
+*/
+
+/*LINTLIBRARY*/
+
+#define LOCALTIME_IMPLEMENTATION
+#include "private.h"
+
+#include "tzfile.h"
+#include <fcntl.h>
+
+#if defined THREAD_SAFE && THREAD_SAFE
+# include <pthread.h>
+static pthread_mutex_t locallock = PTHREAD_MUTEX_INITIALIZER;
+static int lock(void) { return pthread_mutex_lock(&locallock); }
+static void unlock(void) { pthread_mutex_unlock(&locallock); }
+#else
+static int lock(void) { return 0; }
+static void unlock(void) { }
+#endif
+
+/* NETBSD_INSPIRED_EXTERN functions are exported to callers if
+ NETBSD_INSPIRED is defined, and are private otherwise. */
+#if NETBSD_INSPIRED
+# define NETBSD_INSPIRED_EXTERN
+#else
+# define NETBSD_INSPIRED_EXTERN static
+#endif
+
+#ifndef TZ_ABBR_MAX_LEN
+#define TZ_ABBR_MAX_LEN 16
+#endif /* !defined TZ_ABBR_MAX_LEN */
+
+#ifndef TZ_ABBR_CHAR_SET
+#define TZ_ABBR_CHAR_SET \
+ "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
+#endif /* !defined TZ_ABBR_CHAR_SET */
+
+#ifndef TZ_ABBR_ERR_CHAR
+#define TZ_ABBR_ERR_CHAR '_'
+#endif /* !defined TZ_ABBR_ERR_CHAR */
+
+/*
+** SunOS 4.1.1 headers lack O_BINARY.
+*/
+
+#ifdef O_BINARY
+#define OPEN_MODE (O_RDONLY | O_BINARY)
+#endif /* defined O_BINARY */
+#ifndef O_BINARY
+#define OPEN_MODE O_RDONLY
+#endif /* !defined O_BINARY */
+
+#ifndef WILDABBR
+/*
+** Someone might make incorrect use of a time zone abbreviation:
+** 1. They might reference tzname[0] before calling tzset (explicitly
+** or implicitly).
+** 2. They might reference tzname[1] before calling tzset (explicitly
+** or implicitly).
+** 3. They might reference tzname[1] after setting to a time zone
+** in which Daylight Saving Time is never observed.
+** 4. They might reference tzname[0] after setting to a time zone
+** in which Standard Time is never observed.
+** 5. They might reference tm.TM_ZONE after calling offtime.
+** What's best to do in the above cases is open to debate;
+** for now, we just set things up so that in any of the five cases
+** WILDABBR is used. Another possibility: initialize tzname[0] to the
+** string "tzname[0] used before set", and similarly for the other cases.
+** And another: initialize tzname[0] to "ERA", with an explanation in the
+** manual page of what this "time zone abbreviation" means (doing this so
+** that tzname[0] has the "normal" length of three characters).
+*/
+#define WILDABBR " "
+#endif /* !defined WILDABBR */
+
+static const char wildabbr[] = WILDABBR;
+
+static const char gmt[] = "GMT";
+
+/*
+** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
+** Default to US rules as of 2017-05-07.
+** POSIX does not specify the default DST rules;
+** for historical reasons, US rules are a common default.
+*/
+#ifndef TZDEFRULESTRING
+#define TZDEFRULESTRING ",M3.2.0,M11.1.0"
+#endif
+
+struct ttinfo { /* time type information */
+ int_fast32_t tt_gmtoff; /* UT offset in seconds */
+ bool tt_isdst; /* used to set tm_isdst */
+ int tt_abbrind; /* abbreviation list index */
+ bool tt_ttisstd; /* transition is std time */
+ bool tt_ttisgmt; /* transition is UT */
+};
+
+struct lsinfo { /* leap second information */
+ time_t ls_trans; /* transition time */
+ int_fast64_t ls_corr; /* correction to apply */
+};
+
+#define SMALLEST(a, b) (((a) < (b)) ? (a) : (b))
+#define BIGGEST(a, b) (((a) > (b)) ? (a) : (b))
+
+#ifdef TZNAME_MAX
+#define MY_TZNAME_MAX TZNAME_MAX
+#endif /* defined TZNAME_MAX */
+#ifndef TZNAME_MAX
+#define MY_TZNAME_MAX 255
+#endif /* !defined TZNAME_MAX */
+
+struct state {
+ int leapcnt;
+ int timecnt;
+ int typecnt;
+ int charcnt;
+ bool goback;
+ bool goahead;
+ time_t ats[TZ_MAX_TIMES];
+ unsigned char types[TZ_MAX_TIMES];
+ struct ttinfo ttis[TZ_MAX_TYPES];
+ char chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
+ (2 * (MY_TZNAME_MAX + 1)))];
+ struct lsinfo lsis[TZ_MAX_LEAPS];
+ int defaulttype; /* for early times or if no transitions */
+};
+
+enum r_type {
+ JULIAN_DAY, /* Jn = Julian day */
+ DAY_OF_YEAR, /* n = day of year */
+ MONTH_NTH_DAY_OF_WEEK /* Mm.n.d = month, week, day of week */
+};
+
+struct rule {
+ enum r_type r_type; /* type of rule */
+ int r_day; /* day number of rule */
+ int r_week; /* week number of rule */
+ int r_mon; /* month number of rule */
+ int_fast32_t r_time; /* transition time of rule */
+};
+
+static struct tm *gmtsub(struct state const *, time_t const *, int_fast32_t,
+ struct tm *);
+static bool increment_overflow(int *, int);
+static bool increment_overflow_time(time_t *, int_fast32_t);
+static bool normalize_overflow32(int_fast32_t *, int *, int);
+static struct tm *timesub(time_t const *, int_fast32_t, struct state const *,
+ struct tm *);
+static bool typesequiv(struct state const *, int, int);
+static bool tzparse(char const *, struct state *, bool);
+
+#ifdef ALL_STATE
+static struct state * lclptr;
+static struct state * gmtptr;
+#endif /* defined ALL_STATE */
+
+#ifndef ALL_STATE
+static struct state lclmem;
+static struct state gmtmem;
+#define lclptr (&lclmem)
+#define gmtptr (&gmtmem)
+#endif /* State Farm */
+
+#ifndef TZ_STRLEN_MAX
+#define TZ_STRLEN_MAX 255
+#endif /* !defined TZ_STRLEN_MAX */
+
+static char lcl_TZname[TZ_STRLEN_MAX + 1];
+static int lcl_is_set;
+
+/*
+** Section 4.12.3 of X3.159-1989 requires that
+** Except for the strftime function, these functions [asctime,
+** ctime, gmtime, localtime] return values in one of two static
+** objects: a broken-down time structure and an array of char.
+** Thanks to Paul Eggert for noting this.
+*/
+
+static struct tm tm;
+
+#if !HAVE_POSIX_DECLS || TZ_TIME_T
+# if HAVE_TZNAME
+char * tzname[2] = {
+ (char *) wildabbr,
+ (char *) wildabbr
+};
+# endif
+# if USG_COMPAT
+long timezone;
+int daylight;
+# endif
+# ifdef ALTZONE
+long altzone;
+# endif
+#endif
+
+/* Initialize *S to a value based on GMTOFF, ISDST, and ABBRIND. */
+static void
+init_ttinfo(struct ttinfo *s, int_fast32_t gmtoff, bool isdst, int abbrind)
+{
+ s->tt_gmtoff = gmtoff;
+ s->tt_isdst = isdst;
+ s->tt_abbrind = abbrind;
+ s->tt_ttisstd = false;
+ s->tt_ttisgmt = false;
+}
+
+static int_fast32_t
+detzcode(const char *const codep)
+{
+ register int_fast32_t result;
+ register int i;
+ int_fast32_t one = 1;
+ int_fast32_t halfmaxval = one << (32 - 2);
+ int_fast32_t maxval = halfmaxval - 1 + halfmaxval;
+ int_fast32_t minval = -1 - maxval;
+
+ result = codep[0] & 0x7f;
+ for (i = 1; i < 4; ++i)
+ result = (result << 8) | (codep[i] & 0xff);
+
+ if (codep[0] & 0x80) {
+ /* Do two's-complement negation even on non-two's-complement machines.
+ If the result would be minval - 1, return minval. */
+ result -= !TWOS_COMPLEMENT(int_fast32_t) && result != 0;
+ result += minval;
+ }
+ return result;
+}
+
+static int_fast64_t
+detzcode64(const char *const codep)
+{
+ register uint_fast64_t result;
+ register int i;
+ int_fast64_t one = 1;
+ int_fast64_t halfmaxval = one << (64 - 2);
+ int_fast64_t maxval = halfmaxval - 1 + halfmaxval;
+ int_fast64_t minval = -TWOS_COMPLEMENT(int_fast64_t) - maxval;
+
+ result = codep[0] & 0x7f;
+ for (i = 1; i < 8; ++i)
+ result = (result << 8) | (codep[i] & 0xff);
+
+ if (codep[0] & 0x80) {
+ /* Do two's-complement negation even on non-two's-complement machines.
+ If the result would be minval - 1, return minval. */
+ result -= !TWOS_COMPLEMENT(int_fast64_t) && result != 0;
+ result += minval;
+ }
+ return result;
+}
+
+static void
+update_tzname_etc(struct state const *sp, struct ttinfo const *ttisp)
+{
+#if HAVE_TZNAME
+ tzname[ttisp->tt_isdst] = (char *) &sp->chars[ttisp->tt_abbrind];
+#endif
+#if USG_COMPAT
+ if (!ttisp->tt_isdst)
+ timezone = - ttisp->tt_gmtoff;
+#endif
+#ifdef ALTZONE
+ if (ttisp->tt_isdst)
+ altzone = - ttisp->tt_gmtoff;
+#endif
+}
+
+static void
+settzname(void)
+{
+ register struct state * const sp = lclptr;
+ register int i;
+
+#if HAVE_TZNAME
+ tzname[0] = tzname[1] = (char *) (sp ? wildabbr : gmt);
+#endif
+#if USG_COMPAT
+ daylight = 0;
+ timezone = 0;
+#endif
+#ifdef ALTZONE
+ altzone = 0;
+#endif /* defined ALTZONE */
+ if (sp == NULL) {
+ return;
+ }
+ /*
+ ** And to get the latest zone names into tzname. . .
+ */
+ for (i = 0; i < sp->typecnt; ++i) {
+ register const struct ttinfo * const ttisp = &sp->ttis[i];
+ update_tzname_etc(sp, ttisp);
+ }
+ for (i = 0; i < sp->timecnt; ++i) {
+ register const struct ttinfo * const ttisp =
+ &sp->ttis[
+ sp->types[i]];
+ update_tzname_etc(sp, ttisp);
+#if USG_COMPAT
+ if (ttisp->tt_isdst)
+ daylight = 1;
+#endif
+ }
+}
+
+static void
+scrub_abbrs(struct state *sp)
+{
+ int i;
+ /*
+ ** First, replace bogus characters.
+ */
+ for (i = 0; i < sp->charcnt; ++i)
+ if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
+ sp->chars[i] = TZ_ABBR_ERR_CHAR;
+ /*
+ ** Second, truncate long abbreviations.
+ */
+ for (i = 0; i < sp->typecnt; ++i) {
+ register const struct ttinfo * const ttisp = &sp->ttis[i];
+ register char * cp = &sp->chars[ttisp->tt_abbrind];
+
+ if (strlen(cp) > TZ_ABBR_MAX_LEN &&
+ strcmp(cp, GRANDPARENTED) != 0)
+ *(cp + TZ_ABBR_MAX_LEN) = '\0';
+ }
+}
+
+static bool
+differ_by_repeat(const time_t t1, const time_t t0)
+{
+ if (TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
+ return 0;
+ return t1 - t0 == SECSPERREPEAT;
+}
+
+/* Input buffer for data read from a compiled tz file. */
+union input_buffer {
+ /* The first part of the buffer, interpreted as a header. */
+ struct tzhead tzhead;
+
+ /* The entire buffer. */
+ char buf[2 * sizeof(struct tzhead) + 2 * sizeof (struct state)
+ + 4 * TZ_MAX_TIMES];
+};
+
+/* TZDIR with a trailing '/' rather than a trailing '\0'. */
+static char const tzdirslash[sizeof TZDIR] = TZDIR "/";
+
+/* Local storage needed for 'tzloadbody'. */
+union local_storage {
+ /* The results of analyzing the file's contents after it is opened. */
+ struct file_analysis {
+ /* The input buffer. */
+ union input_buffer u;
+
+ /* A temporary state used for parsing a TZ string in the file. */
+ struct state st;
+ } u;
+
+ /* The file name to be opened. */
+ char fullname[BIGGEST(sizeof (struct file_analysis),
+ sizeof tzdirslash + 1024)];
+};
+
+/* Load tz data from the file named NAME into *SP. Read extended
+ format if DOEXTEND. Use *LSP for temporary storage. Return 0 on
+ success, an errno value on failure. */
+static int
+tzloadbody(char const *name, struct state *sp, bool doextend,
+ union local_storage *lsp)
+{
+ register int i;
+ register int fid;
+ register int stored;
+ register ssize_t nread;
+ register bool doaccess;
+ register union input_buffer *up = &lsp->u.u;
+ register int tzheadsize = sizeof (struct tzhead);
+
+ sp->goback = sp->goahead = false;
+
+ if (! name) {
+ name = TZDEFAULT;
+ if (! name)
+ return EINVAL;
+ }
+
+ if (name[0] == ':')
+ ++name;
+#ifdef SUPPRESS_TZDIR
+ /* Do not prepend TZDIR. This is intended for specialized
+ applications only, due to its security implications. */
+ doaccess = true;
+#else
+ doaccess = name[0] == '/';
+#endif
+ if (!doaccess) {
+ size_t namelen = strlen(name);
+ if (sizeof lsp->fullname - sizeof tzdirslash <= namelen)
+ return ENAMETOOLONG;
+
+ /* Create a string "TZDIR/NAME". Using sprintf here
+ would pull in stdio (and would fail if the
+ resulting string length exceeded INT_MAX!). */
+ memcpy(lsp->fullname, tzdirslash, sizeof tzdirslash);
+ strcpy(lsp->fullname + sizeof tzdirslash, name);
+
+ /* Set doaccess if '.' (as in "../") shows up in name. */
+ if (strchr(name, '.'))
+ doaccess = true;
+ name = lsp->fullname;
+ }
+ if (doaccess && access(name, R_OK) != 0)
+ return errno;
+ fid = open(name, OPEN_MODE);
+ if (fid < 0)
+ return errno;
+
+ nread = read(fid, up->buf, sizeof up->buf);
+ if (nread < tzheadsize) {
+ int err = nread < 0 ? errno : EINVAL;
+ close(fid);
+ return err;
+ }
+ if (close(fid) < 0)
+ return errno;
+ for (stored = 4; stored <= 8; stored *= 2) {
+ int_fast32_t ttisstdcnt = detzcode(up->tzhead.tzh_ttisstdcnt);
+ int_fast32_t ttisgmtcnt = detzcode(up->tzhead.tzh_ttisgmtcnt);
+ int_fast64_t prevtr = 0;
+ int_fast32_t prevcorr = 0;
+ int_fast32_t leapcnt = detzcode(up->tzhead.tzh_leapcnt);
+ int_fast32_t timecnt = detzcode(up->tzhead.tzh_timecnt);
+ int_fast32_t typecnt = detzcode(up->tzhead.tzh_typecnt);
+ int_fast32_t charcnt = detzcode(up->tzhead.tzh_charcnt);
+ char const *p = up->buf + tzheadsize;
+ if (! (0 <= leapcnt && leapcnt < TZ_MAX_LEAPS
+ && 0 < typecnt && typecnt < TZ_MAX_TYPES
+ && 0 <= timecnt && timecnt < TZ_MAX_TIMES
+ && 0 <= charcnt && charcnt < TZ_MAX_CHARS
+ && (ttisstdcnt == typecnt || ttisstdcnt == 0)
+ && (ttisgmtcnt == typecnt || ttisgmtcnt == 0)))
+ return EINVAL;
+ if (nread
+ < (tzheadsize /* struct tzhead */
+ + timecnt * stored /* ats */
+ + timecnt /* types */
+ + typecnt * 6 /* ttinfos */
+ + charcnt /* chars */
+ + leapcnt * (stored + 4) /* lsinfos */
+ + ttisstdcnt /* ttisstds */
+ + ttisgmtcnt)) /* ttisgmts */
+ return EINVAL;
+ sp->leapcnt = leapcnt;
+ sp->timecnt = timecnt;
+ sp->typecnt = typecnt;
+ sp->charcnt = charcnt;
+
+ /* Read transitions, discarding those out of time_t range.
+ But pretend the last transition before TIME_T_MIN
+ occurred at TIME_T_MIN. */
+ timecnt = 0;
+ for (i = 0; i < sp->timecnt; ++i) {
+ int_fast64_t at
+ = stored == 4 ? detzcode(p) : detzcode64(p);
+ sp->types[i] = at <= TIME_T_MAX;
+ if (sp->types[i]) {
+ time_t attime
+ = ((TYPE_SIGNED(time_t) ? at < TIME_T_MIN : at < 0)
+ ? TIME_T_MIN : at);
+ if (timecnt && attime <= sp->ats[timecnt - 1]) {
+ if (attime < sp->ats[timecnt - 1])
+ return EINVAL;
+ sp->types[i - 1] = 0;
+ timecnt--;
+ }
+ sp->ats[timecnt++] = attime;
+ }
+ p += stored;
+ }
+
+ timecnt = 0;
+ for (i = 0; i < sp->timecnt; ++i) {
+ unsigned char typ = *p++;
+ if (sp->typecnt <= typ)
+ return EINVAL;
+ if (sp->types[i])
+ sp->types[timecnt++] = typ;
+ }
+ sp->timecnt = timecnt;
+ for (i = 0; i < sp->typecnt; ++i) {
+ register struct ttinfo * ttisp;
+ unsigned char isdst, abbrind;
+
+ ttisp = &sp->ttis[i];
+ ttisp->tt_gmtoff = detzcode(p);
+ p += 4;
+ isdst = *p++;
+ if (! (isdst < 2))
+ return EINVAL;
+ ttisp->tt_isdst = isdst;
+ abbrind = *p++;
+ if (! (abbrind < sp->charcnt))
+ return EINVAL;
+ ttisp->tt_abbrind = abbrind;
+ }
+ for (i = 0; i < sp->charcnt; ++i)
+ sp->chars[i] = *p++;
+ sp->chars[i] = '\0'; /* ensure '\0' at end */
+
+ /* Read leap seconds, discarding those out of time_t range. */
+ leapcnt = 0;
+ for (i = 0; i < sp->leapcnt; ++i) {
+ int_fast64_t tr = stored == 4 ? detzcode(p) : detzcode64(p);
+ int_fast32_t corr = detzcode(p + stored);
+ p += stored + 4;
+ /* Leap seconds cannot occur before the Epoch. */
+ if (tr < 0)
+ return EINVAL;
+ if (tr <= TIME_T_MAX) {
+ /* Leap seconds cannot occur more than once per UTC month,
+ and UTC months are at least 28 days long (minus 1
+ second for a negative leap second). Each leap second's
+ correction must differ from the previous one's by 1
+ second. */
+ if (tr - prevtr < 28 * SECSPERDAY - 1
+ || (corr != prevcorr - 1 && corr != prevcorr + 1))
+ return EINVAL;
+ sp->lsis[leapcnt].ls_trans = prevtr = tr;
+ sp->lsis[leapcnt].ls_corr = prevcorr = corr;
+ leapcnt++;
+ }
+ }
+ sp->leapcnt = leapcnt;
+
+ for (i = 0; i < sp->typecnt; ++i) {
+ register struct ttinfo * ttisp;
+
+ ttisp = &sp->ttis[i];
+ if (ttisstdcnt == 0)
+ ttisp->tt_ttisstd = false;
+ else {
+ if (*p != true && *p != false)
+ return EINVAL;
+ ttisp->tt_ttisstd = *p++;
+ }
+ }
+ for (i = 0; i < sp->typecnt; ++i) {
+ register struct ttinfo * ttisp;
+
+ ttisp = &sp->ttis[i];
+ if (ttisgmtcnt == 0)
+ ttisp->tt_ttisgmt = false;
+ else {
+ if (*p != true && *p != false)
+ return EINVAL;
+ ttisp->tt_ttisgmt = *p++;
+ }
+ }
+ /*
+ ** If this is an old file, we're done.
+ */
+ if (up->tzhead.tzh_version[0] == '\0')
+ break;
+ nread -= p - up->buf;
+ memmove(up->buf, p, nread);
+ }
+ if (doextend && nread > 2 &&
+ up->buf[0] == '\n' && up->buf[nread - 1] == '\n' &&
+ sp->typecnt + 2 <= TZ_MAX_TYPES) {
+ struct state *ts = &lsp->u.st;
+
+ up->buf[nread - 1] = '\0';
+ if (tzparse(&up->buf[1], ts, false)
+ && ts->typecnt == 2) {
+
+ /* Attempt to reuse existing abbreviations.
+ Without this, America/Anchorage would be right on
+ the edge after 2037 when TZ_MAX_CHARS is 50, as
+ sp->charcnt equals 40 (for LMT AST AWT APT AHST
+ AHDT YST AKDT AKST) and ts->charcnt equals 10
+ (for AKST AKDT). Reusing means sp->charcnt can
+ stay 40 in this example. */
+ int gotabbr = 0;
+ int charcnt = sp->charcnt;
+ for (i = 0; i < 2; i++) {
+ char *tsabbr = ts->chars + ts->ttis[i].tt_abbrind;
+ int j;
+ for (j = 0; j < charcnt; j++)
+ if (strcmp(sp->chars + j, tsabbr) == 0) {
+ ts->ttis[i].tt_abbrind = j;
+ gotabbr++;
+ break;
+ }
+ if (! (j < charcnt)) {
+ int tsabbrlen = strlen(tsabbr);
+ if (j + tsabbrlen < TZ_MAX_CHARS) {
+ strcpy(sp->chars + j, tsabbr);
+ charcnt = j + tsabbrlen + 1;
+ ts->ttis[i].tt_abbrind = j;
+ gotabbr++;
+ }
+ }
+ }
+ if (gotabbr == 2) {
+ sp->charcnt = charcnt;
+
+ /* Ignore any trailing, no-op transitions generated
+ by zic as they don't help here and can run afoul
+ of bugs in zic 2016j or earlier. */
+ while (1 < sp->timecnt
+ && (sp->types[sp->timecnt - 1]
+ == sp->types[sp->timecnt - 2]))
+ sp->timecnt--;
+
+ for (i = 0; i < ts->timecnt; i++)
+ if (sp->ats[sp->timecnt - 1] < ts->ats[i])
+ break;
+ while (i < ts->timecnt
+ && sp->timecnt < TZ_MAX_TIMES) {
+ sp->ats[sp->timecnt] = ts->ats[i];
+ sp->types[sp->timecnt] = (sp->typecnt
+ + ts->types[i]);
+ sp->timecnt++;
+ i++;
+ }
+ sp->ttis[sp->typecnt++] = ts->ttis[0];
+ sp->ttis[sp->typecnt++] = ts->ttis[1];
+ }
+ }
+ }
+ if (sp->timecnt > 1) {
+ for (i = 1; i < sp->timecnt; ++i)
+ if (typesequiv(sp, sp->types[i], sp->types[0]) &&
+ differ_by_repeat(sp->ats[i], sp->ats[0])) {
+ sp->goback = true;
+ break;
+ }
+ for (i = sp->timecnt - 2; i >= 0; --i)
+ if (typesequiv(sp, sp->types[sp->timecnt - 1],
+ sp->types[i]) &&
+ differ_by_repeat(sp->ats[sp->timecnt - 1],
+ sp->ats[i])) {
+ sp->goahead = true;
+ break;
+ }
+ }
+ /*
+ ** If type 0 is unused in transitions,
+ ** it's the type to use for early times.
+ */
+ for (i = 0; i < sp->timecnt; ++i)
+ if (sp->types[i] == 0)
+ break;
+ i = i < sp->timecnt ? -1 : 0;
+ /*
+ ** Absent the above,
+ ** if there are transition times
+ ** and the first transition is to a daylight time
+ ** find the standard type less than and closest to
+ ** the type of the first transition.
+ */
+ if (i < 0 && sp->timecnt > 0 && sp->ttis[sp->types[0]].tt_isdst) {
+ i = sp->types[0];
+ while (--i >= 0)
+ if (!sp->ttis[i].tt_isdst)
+ break;
+ }
+ /*
+ ** If no result yet, find the first standard type.
+ ** If there is none, punt to type zero.
+ */
+ if (i < 0) {
+ i = 0;
+ while (sp->ttis[i].tt_isdst)
+ if (++i >= sp->typecnt) {
+ i = 0;
+ break;
+ }
+ }
+ sp->defaulttype = i;
+ return 0;
+}
+
+/* Load tz data from the file named NAME into *SP. Read extended
+ format if DOEXTEND. Return 0 on success, an errno value on failure. */
+static int
+tzload(char const *name, struct state *sp, bool doextend)
+{
+#ifdef ALL_STATE
+ union local_storage *lsp = malloc(sizeof *lsp);
+ if (!lsp)
+ return errno;
+ else {
+ int err = tzloadbody(name, sp, doextend, lsp);
+ free(lsp);
+ return err;
+ }
+#else
+ union local_storage ls;
+ return tzloadbody(name, sp, doextend, &ls);
+#endif
+}
+
+static bool
+typesequiv(const struct state *sp, int a, int b)
+{
+ register bool result;
+
+ if (sp == NULL ||
+ a < 0 || a >= sp->typecnt ||
+ b < 0 || b >= sp->typecnt)
+ result = false;
+ else {
+ register const struct ttinfo * ap = &sp->ttis[a];
+ register const struct ttinfo * bp = &sp->ttis[b];
+ result = ap->tt_gmtoff == bp->tt_gmtoff &&
+ ap->tt_isdst == bp->tt_isdst &&
+ ap->tt_ttisstd == bp->tt_ttisstd &&
+ ap->tt_ttisgmt == bp->tt_ttisgmt &&
+ strcmp(&sp->chars[ap->tt_abbrind],
+ &sp->chars[bp->tt_abbrind]) == 0;
+ }
+ return result;
+}
+
+static const int mon_lengths[2][MONSPERYEAR] = {
+ { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
+ { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
+};
+
+static const int year_lengths[2] = {
+ DAYSPERNYEAR, DAYSPERLYEAR
+};
+
+/*
+** Given a pointer into a time zone string, scan until a character that is not
+** a valid character in a zone name is found. Return a pointer to that
+** character.
+*/
+
+static const char *
+getzname(register const char *strp)
+{
+ register char c;
+
+ while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
+ c != '+')
+ ++strp;
+ return strp;
+}
+
+/*
+** Given a pointer into an extended time zone string, scan until the ending
+** delimiter of the zone name is located. Return a pointer to the delimiter.
+**
+** As with getzname above, the legal character set is actually quite
+** restricted, with other characters producing undefined results.
+** We don't do any checking here; checking is done later in common-case code.
+*/
+
+static const char *
+getqzname(register const char *strp, const int delim)
+{
+ register int c;
+
+ while ((c = *strp) != '\0' && c != delim)
+ ++strp;
+ return strp;
+}
+
+/*
+** Given a pointer into a time zone string, extract a number from that string.
+** Check that the number is within a specified range; if it is not, return
+** NULL.
+** Otherwise, return a pointer to the first character not part of the number.
+*/
+
+static const char *
+getnum(register const char *strp, int *const nump, const int min, const int max)
+{
+ register char c;
+ register int num;
+
+ if (strp == NULL || !is_digit(c = *strp))
+ return NULL;
+ num = 0;
+ do {
+ num = num * 10 + (c - '0');
+ if (num > max)
+ return NULL; /* illegal value */
+ c = *++strp;
+ } while (is_digit(c));
+ if (num < min)
+ return NULL; /* illegal value */
+ *nump = num;
+ return strp;
+}
+
+/*
+** Given a pointer into a time zone string, extract a number of seconds,
+** in hh[:mm[:ss]] form, from the string.
+** If any error occurs, return NULL.
+** Otherwise, return a pointer to the first character not part of the number
+** of seconds.
+*/
+
+static const char *
+getsecs(register const char *strp, int_fast32_t *const secsp)
+{
+ int num;
+
+ /*
+ ** 'HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
+ ** "M10.4.6/26", which does not conform to Posix,
+ ** but which specifies the equivalent of
+ ** "02:00 on the first Sunday on or after 23 Oct".
+ */
+ strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
+ if (strp == NULL)
+ return NULL;
+ *secsp = num * (int_fast32_t) SECSPERHOUR;
+ if (*strp == ':') {
+ ++strp;
+ strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
+ if (strp == NULL)
+ return NULL;
+ *secsp += num * SECSPERMIN;
+ if (*strp == ':') {
+ ++strp;
+ /* 'SECSPERMIN' allows for leap seconds. */
+ strp = getnum(strp, &num, 0, SECSPERMIN);
+ if (strp == NULL)
+ return NULL;
+ *secsp += num;
+ }
+ }
+ return strp;
+}
+
+/*
+** Given a pointer into a time zone string, extract an offset, in
+** [+-]hh[:mm[:ss]] form, from the string.
+** If any error occurs, return NULL.
+** Otherwise, return a pointer to the first character not part of the time.
+*/
+
+static const char *
+getoffset(register const char *strp, int_fast32_t *const offsetp)
+{
+ register bool neg = false;
+
+ if (*strp == '-') {
+ neg = true;
+ ++strp;
+ } else if (*strp == '+')
+ ++strp;
+ strp = getsecs(strp, offsetp);
+ if (strp == NULL)
+ return NULL; /* illegal time */
+ if (neg)
+ *offsetp = -*offsetp;
+ return strp;
+}
+
+/*
+** Given a pointer into a time zone string, extract a rule in the form
+** date[/time]. See POSIX section 8 for the format of "date" and "time".
+** If a valid rule is not found, return NULL.
+** Otherwise, return a pointer to the first character not part of the rule.
+*/
+
+static const char *
+getrule(const char *strp, register struct rule *const rulep)
+{
+ if (*strp == 'J') {
+ /*
+ ** Julian day.
+ */
+ rulep->r_type = JULIAN_DAY;
+ ++strp;
+ strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
+ } else if (*strp == 'M') {
+ /*
+ ** Month, week, day.
+ */
+ rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
+ ++strp;
+ strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
+ if (strp == NULL)
+ return NULL;
+ if (*strp++ != '.')
+ return NULL;
+ strp = getnum(strp, &rulep->r_week, 1, 5);
+ if (strp == NULL)
+ return NULL;
+ if (*strp++ != '.')
+ return NULL;
+ strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
+ } else if (is_digit(*strp)) {
+ /*
+ ** Day of year.
+ */
+ rulep->r_type = DAY_OF_YEAR;
+ strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
+ } else return NULL; /* invalid format */
+ if (strp == NULL)
+ return NULL;
+ if (*strp == '/') {
+ /*
+ ** Time specified.
+ */
+ ++strp;
+ strp = getoffset(strp, &rulep->r_time);
+ } else rulep->r_time = 2 * SECSPERHOUR; /* default = 2:00:00 */
+ return strp;
+}
+
+/*
+** Given a year, a rule, and the offset from UT at the time that rule takes
+** effect, calculate the year-relative time that rule takes effect.
+*/
+
+static int_fast32_t
+transtime(const int year, register const struct rule *const rulep,
+ const int_fast32_t offset)
+{
+ register bool leapyear;
+ register int_fast32_t value;
+ register int i;
+ int d, m1, yy0, yy1, yy2, dow;
+
+ INITIALIZE(value);
+ leapyear = isleap(year);
+ switch (rulep->r_type) {
+
+ case JULIAN_DAY:
+ /*
+ ** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
+ ** years.
+ ** In non-leap years, or if the day number is 59 or less, just
+ ** add SECSPERDAY times the day number-1 to the time of
+ ** January 1, midnight, to get the day.
+ */
+ value = (rulep->r_day - 1) * SECSPERDAY;
+ if (leapyear && rulep->r_day >= 60)
+ value += SECSPERDAY;
+ break;
+
+ case DAY_OF_YEAR:
+ /*
+ ** n - day of year.
+ ** Just add SECSPERDAY times the day number to the time of
+ ** January 1, midnight, to get the day.
+ */
+ value = rulep->r_day * SECSPERDAY;
+ break;
+
+ case MONTH_NTH_DAY_OF_WEEK:
+ /*
+ ** Mm.n.d - nth "dth day" of month m.
+ */
+
+ /*
+ ** Use Zeller's Congruence to get day-of-week of first day of
+ ** month.
+ */
+ m1 = (rulep->r_mon + 9) % 12 + 1;
+ yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
+ yy1 = yy0 / 100;
+ yy2 = yy0 % 100;
+ dow = ((26 * m1 - 2) / 10 +
+ 1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
+ if (dow < 0)
+ dow += DAYSPERWEEK;
+
+ /*
+ ** "dow" is the day-of-week of the first day of the month. Get
+ ** the day-of-month (zero-origin) of the first "dow" day of the
+ ** month.
+ */
+ d = rulep->r_day - dow;
+ if (d < 0)
+ d += DAYSPERWEEK;
+ for (i = 1; i < rulep->r_week; ++i) {
+ if (d + DAYSPERWEEK >=
+ mon_lengths[leapyear][rulep->r_mon - 1])
+ break;
+ d += DAYSPERWEEK;
+ }
+
+ /*
+ ** "d" is the day-of-month (zero-origin) of the day we want.
+ */
+ value = d * SECSPERDAY;
+ for (i = 0; i < rulep->r_mon - 1; ++i)
+ value += mon_lengths[leapyear][i] * SECSPERDAY;
+ break;
+ }
+
+ /*
+ ** "value" is the year-relative time of 00:00:00 UT on the day in
+ ** question. To get the year-relative time of the specified local
+ ** time on that day, add the transition time and the current offset
+ ** from UT.
+ */
+ return value + rulep->r_time + offset;
+}
+
+/*
+** Given a POSIX section 8-style TZ string, fill in the rule tables as
+** appropriate.
+*/
+
+static bool
+tzparse(const char *name, struct state *sp, bool lastditch)
+{
+ const char * stdname;
+ const char * dstname;
+ size_t stdlen;
+ size_t dstlen;
+ size_t charcnt;
+ int_fast32_t stdoffset;
+ int_fast32_t dstoffset;
+ register char * cp;
+ register bool load_ok;
+
+ stdname = name;
+ if (lastditch) {
+ stdlen = sizeof gmt - 1;
+ name += stdlen;
+ stdoffset = 0;
+ } else {
+ if (*name == '<') {
+ name++;
+ stdname = name;
+ name = getqzname(name, '>');
+ if (*name != '>')
+ return false;
+ stdlen = name - stdname;
+ name++;
+ } else {
+ name = getzname(name);
+ stdlen = name - stdname;
+ }
+ if (!stdlen)
+ return false;
+ name = getoffset(name, &stdoffset);
+ if (name == NULL)
+ return false;
+ }
+ charcnt = stdlen + 1;
+ if (sizeof sp->chars < charcnt)
+ return false;
+ load_ok = tzload(TZDEFRULES, sp, false) == 0;
+ if (!load_ok)
+ sp->leapcnt = 0; /* so, we're off a little */
+ if (*name != '\0') {
+ if (*name == '<') {
+ dstname = ++name;
+ name = getqzname(name, '>');
+ if (*name != '>')
+ return false;
+ dstlen = name - dstname;
+ name++;
+ } else {
+ dstname = name;
+ name = getzname(name);
+ dstlen = name - dstname; /* length of DST zone name */
+ }
+ if (!dstlen)
+ return false;
+ charcnt += dstlen + 1;
+ if (sizeof sp->chars < charcnt)
+ return false;
+ if (*name != '\0' && *name != ',' && *name != ';') {
+ name = getoffset(name, &dstoffset);
+ if (name == NULL)
+ return false;
+ } else dstoffset = stdoffset - SECSPERHOUR;
+ if (*name == '\0' && !load_ok)
+ name = TZDEFRULESTRING;
+ if (*name == ',' || *name == ';') {
+ struct rule start;
+ struct rule end;
+ register int year;
+ register int yearlim;
+ register int timecnt;
+ time_t janfirst;
+ int_fast32_t janoffset = 0;
+ int yearbeg;
+
+ ++name;
+ if ((name = getrule(name, &start)) == NULL)
+ return false;
+ if (*name++ != ',')
+ return false;
+ if ((name = getrule(name, &end)) == NULL)
+ return false;
+ if (*name != '\0')
+ return false;
+ sp->typecnt = 2; /* standard time and DST */
+ /*
+ ** Two transitions per year, from EPOCH_YEAR forward.
+ */
+ init_ttinfo(&sp->ttis[0], -dstoffset, true, stdlen + 1);
+ init_ttinfo(&sp->ttis[1], -stdoffset, false, 0);
+ sp->defaulttype = 0;
+ timecnt = 0;
+ janfirst = 0;
+ yearbeg = EPOCH_YEAR;
+
+ do {
+ int_fast32_t yearsecs
+ = year_lengths[isleap(yearbeg - 1)] * SECSPERDAY;
+ yearbeg--;
+ if (increment_overflow_time(&janfirst, -yearsecs)) {
+ janoffset = -yearsecs;
+ break;
+ }
+ } while (EPOCH_YEAR - YEARSPERREPEAT / 2 < yearbeg);
+
+ yearlim = yearbeg + YEARSPERREPEAT + 1;
+ for (year = yearbeg; year < yearlim; year++) {
+ int_fast32_t
+ starttime = transtime(year, &start, stdoffset),
+ endtime = transtime(year, &end, dstoffset);
+ int_fast32_t
+ yearsecs = (year_lengths[isleap(year)]
+ * SECSPERDAY);
+ bool reversed = endtime < starttime;
+ if (reversed) {
+ int_fast32_t swap = starttime;
+ starttime = endtime;
+ endtime = swap;
+ }
+ if (reversed
+ || (starttime < endtime
+ && (endtime - starttime
+ < (yearsecs
+ + (stdoffset - dstoffset))))) {
+ if (TZ_MAX_TIMES - 2 < timecnt)
+ break;
+ sp->ats[timecnt] = janfirst;
+ if (! increment_overflow_time
+ (&sp->ats[timecnt],
+ janoffset + starttime))
+ sp->types[timecnt++] = reversed;
+ else if (janoffset)
+ sp->defaulttype = reversed;
+ sp->ats[timecnt] = janfirst;
+ if (! increment_overflow_time
+ (&sp->ats[timecnt],
+ janoffset + endtime)) {
+ sp->types[timecnt++] = !reversed;
+ yearlim = year + YEARSPERREPEAT + 1;
+ } else if (janoffset)
+ sp->defaulttype = !reversed;
+ }
+ if (increment_overflow_time
+ (&janfirst, janoffset + yearsecs))
+ break;
+ janoffset = 0;
+ }
+ sp->timecnt = timecnt;
+ if (! timecnt)
+ sp->typecnt = 1; /* Perpetual DST. */
+ else if (YEARSPERREPEAT < year - yearbeg)
+ sp->goback = sp->goahead = true;
+ } else {
+ register int_fast32_t theirstdoffset;
+ register int_fast32_t theirdstoffset;
+ register int_fast32_t theiroffset;
+ register bool isdst;
+ register int i;
+ register int j;
+
+ if (*name != '\0')
+ return false;
+ /*
+ ** Initial values of theirstdoffset and theirdstoffset.
+ */
+ theirstdoffset = 0;
+ for (i = 0; i < sp->timecnt; ++i) {
+ j = sp->types[i];
+ if (!sp->ttis[j].tt_isdst) {
+ theirstdoffset =
+ -sp->ttis[j].tt_gmtoff;
+ break;
+ }
+ }
+ theirdstoffset = 0;
+ for (i = 0; i < sp->timecnt; ++i) {
+ j = sp->types[i];
+ if (sp->ttis[j].tt_isdst) {
+ theirdstoffset =
+ -sp->ttis[j].tt_gmtoff;
+ break;
+ }
+ }
+ /*
+ ** Initially we're assumed to be in standard time.
+ */
+ isdst = false;
+ theiroffset = theirstdoffset;
+ /*
+ ** Now juggle transition times and types
+ ** tracking offsets as you do.
+ */
+ for (i = 0; i < sp->timecnt; ++i) {
+ j = sp->types[i];
+ sp->types[i] = sp->ttis[j].tt_isdst;
+ if (sp->ttis[j].tt_ttisgmt) {
+ /* No adjustment to transition time */
+ } else {
+ /*
+ ** If daylight saving time is in
+ ** effect, and the transition time was
+ ** not specified as standard time, add
+ ** the daylight saving time offset to
+ ** the transition time; otherwise, add
+ ** the standard time offset to the
+ ** transition time.
+ */
+ /*
+ ** Transitions from DST to DDST
+ ** will effectively disappear since
+ ** POSIX provides for only one DST
+ ** offset.
+ */
+ if (isdst && !sp->ttis[j].tt_ttisstd) {
+ sp->ats[i] += dstoffset -
+ theirdstoffset;
+ } else {
+ sp->ats[i] += stdoffset -
+ theirstdoffset;
+ }
+ }
+ theiroffset = -sp->ttis[j].tt_gmtoff;
+ if (sp->ttis[j].tt_isdst)
+ theirdstoffset = theiroffset;
+ else theirstdoffset = theiroffset;
+ }
+ /*
+ ** Finally, fill in ttis.
+ */
+ init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
+ init_ttinfo(&sp->ttis[1], -dstoffset, true, stdlen + 1);
+ sp->typecnt = 2;
+ sp->defaulttype = 0;
+ }
+ } else {
+ dstlen = 0;
+ sp->typecnt = 1; /* only standard time */
+ sp->timecnt = 0;
+ init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
+ sp->defaulttype = 0;
+ }
+ sp->charcnt = charcnt;
+ cp = sp->chars;
+ memcpy(cp, stdname, stdlen);
+ cp += stdlen;
+ *cp++ = '\0';
+ if (dstlen != 0) {
+ memcpy(cp, dstname, dstlen);
+ *(cp + dstlen) = '\0';
+ }
+ return true;
+}
+
+static void
+gmtload(struct state *const sp)
+{
+ if (tzload(gmt, sp, true) != 0)
+ tzparse(gmt, sp, true);
+}
+
+/* Initialize *SP to a value appropriate for the TZ setting NAME.
+ Return 0 on success, an errno value on failure. */
+static int
+zoneinit(struct state *sp, char const *name)
+{
+ if (name && ! name[0]) {
+ /*
+ ** User wants it fast rather than right.
+ */
+ sp->leapcnt = 0; /* so, we're off a little */
+ sp->timecnt = 0;
+ sp->typecnt = 0;
+ sp->charcnt = 0;
+ sp->goback = sp->goahead = false;
+ init_ttinfo(&sp->ttis[0], 0, false, 0);
+ strcpy(sp->chars, gmt);
+ sp->defaulttype = 0;
+ return 0;
+ } else {
+ int err = tzload(name, sp, true);
+ if (err != 0 && name && name[0] != ':' && tzparse(name, sp, false))
+ err = 0;
+ if (err == 0)
+ scrub_abbrs(sp);
+ return err;
+ }
+}
+
+static void
+tzsetlcl(char const *name)
+{
+ struct state *sp = lclptr;
+ int lcl = name ? strlen(name) < sizeof lcl_TZname : -1;
+ if (lcl < 0
+ ? lcl_is_set < 0
+ : 0 < lcl_is_set && strcmp(lcl_TZname, name) == 0)
+ return;
+#ifdef ALL_STATE
+ if (! sp)
+ lclptr = sp = malloc(sizeof *lclptr);
+#endif /* defined ALL_STATE */
+ if (sp) {
+ if (zoneinit(sp, name) != 0)
+ zoneinit(sp, "");
+ if (0 < lcl)
+ strcpy(lcl_TZname, name);
+ }
+ settzname();
+ lcl_is_set = lcl;
+}
+
+#ifdef STD_INSPIRED
+void
+tzsetwall(void)
+{
+ if (lock() != 0)
+ return;
+ tzsetlcl(NULL);
+ unlock();
+}
+#endif
+
+static void
+tzset_unlocked(void)
+{
+ tzsetlcl(getenv("TZ"));
+}
+
+void
+tzset(void)
+{
+ if (lock() != 0)
+ return;
+ tzset_unlocked();
+ unlock();
+}
+
+static void
+gmtcheck(void)
+{
+ static bool gmt_is_set;
+ if (lock() != 0)
+ return;
+ if (! gmt_is_set) {
+#ifdef ALL_STATE
+ gmtptr = malloc(sizeof *gmtptr);
+#endif
+ if (gmtptr)
+ gmtload(gmtptr);
+ gmt_is_set = true;
+ }
+ unlock();
+}
+
+#if NETBSD_INSPIRED
+
+timezone_t
+tzalloc(char const *name)
+{
+ timezone_t sp = malloc(sizeof *sp);
+ if (sp) {
+ int err = zoneinit(sp, name);
+ if (err != 0) {
+ free(sp);
+ errno = err;
+ return NULL;
+ }
+ }
+ return sp;
+}
+
+void
+tzfree(timezone_t sp)
+{
+ free(sp);
+}
+
+/*
+** NetBSD 6.1.4 has ctime_rz, but omit it because POSIX says ctime and
+** ctime_r are obsolescent and have potential security problems that
+** ctime_rz would share. Callers can instead use localtime_rz + strftime.
+**
+** NetBSD 6.1.4 has tzgetname, but omit it because it doesn't work
+** in zones with three or more time zone abbreviations.
+** Callers can instead use localtime_rz + strftime.
+*/
+
+#endif
+
+/*
+** The easy way to behave "as if no library function calls" localtime
+** is to not call it, so we drop its guts into "localsub", which can be
+** freely called. (And no, the PANS doesn't require the above behavior,
+** but it *is* desirable.)
+**
+** If successful and SETNAME is nonzero,
+** set the applicable parts of tzname, timezone and altzone;
+** however, it's OK to omit this step if the time zone is POSIX-compatible,
+** since in that case tzset should have already done this step correctly.
+** SETNAME's type is intfast32_t for compatibility with gmtsub,
+** but it is actually a boolean and its value should be 0 or 1.
+*/
+
+/*ARGSUSED*/
+static struct tm *
+localsub(struct state const *sp, time_t const *timep, int_fast32_t setname,
+ struct tm *const tmp)
+{
+ register const struct ttinfo * ttisp;
+ register int i;
+ register struct tm * result;
+ const time_t t = *timep;
+
+ if (sp == NULL) {
+ /* Don't bother to set tzname etc.; tzset has already done it. */
+ return gmtsub(gmtptr, timep, 0, tmp);
+ }
+ if ((sp->goback && t < sp->ats[0]) ||
+ (sp->goahead && t > sp->ats[sp->timecnt - 1])) {
+ time_t newt = t;
+ register time_t seconds;
+ register time_t years;
+
+ if (t < sp->ats[0])
+ seconds = sp->ats[0] - t;
+ else seconds = t - sp->ats[sp->timecnt - 1];
+ --seconds;
+ years = (seconds / SECSPERREPEAT + 1) * YEARSPERREPEAT;
+ seconds = years * AVGSECSPERYEAR;
+ if (t < sp->ats[0])
+ newt += seconds;
+ else newt -= seconds;
+ if (newt < sp->ats[0] ||
+ newt > sp->ats[sp->timecnt - 1])
+ return NULL; /* "cannot happen" */
+ result = localsub(sp, &newt, setname, tmp);
+ if (result) {
+ register int_fast64_t newy;
+
+ newy = result->tm_year;
+ if (t < sp->ats[0])
+ newy -= years;
+ else newy += years;
+ if (! (INT_MIN <= newy && newy <= INT_MAX))
+ return NULL;
+ result->tm_year = newy;
+ }
+ return result;
+ }
+ if (sp->timecnt == 0 || t < sp->ats[0]) {
+ i = sp->defaulttype;
+ } else {
+ register int lo = 1;
+ register int hi = sp->timecnt;
+
+ while (lo < hi) {
+ register int mid = (lo + hi) >> 1;
+
+ if (t < sp->ats[mid])
+ hi = mid;
+ else lo = mid + 1;
+ }
+ i = (int) sp->types[lo - 1];
+ }
+ ttisp = &sp->ttis[i];
+ /*
+ ** To get (wrong) behavior that's compatible with System V Release 2.0
+ ** you'd replace the statement below with
+ ** t += ttisp->tt_gmtoff;
+ ** timesub(&t, 0L, sp, tmp);
+ */
+ result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
+ if (result) {
+ result->tm_isdst = ttisp->tt_isdst;
+#ifdef TM_ZONE
+ result->TM_ZONE = (char *) &sp->chars[ttisp->tt_abbrind];
+#endif /* defined TM_ZONE */
+ if (setname)
+ update_tzname_etc(sp, ttisp);
+ }
+ return result;
+}
+
+#if NETBSD_INSPIRED
+
+struct tm *
+localtime_rz(struct state *sp, time_t const *timep, struct tm *tmp)
+{
+ return localsub(sp, timep, 0, tmp);
+}
+
+#endif
+
+static struct tm *
+localtime_tzset(time_t const *timep, struct tm *tmp, bool setname)
+{
+ int err = lock();
+ if (err) {
+ errno = err;
+ return NULL;
+ }
+ if (setname || !lcl_is_set)
+ tzset_unlocked();
+ tmp = localsub(lclptr, timep, setname, tmp);
+ unlock();
+ return tmp;
+}
+
+struct tm *
+localtime(const time_t *timep)
+{
+ return localtime_tzset(timep, &tm, true);
+}
+
+struct tm *
+localtime_r(const time_t *timep, struct tm *tmp)
+{
+ return localtime_tzset(timep, tmp, false);
+}
+
+/*
+** gmtsub is to gmtime as localsub is to localtime.
+*/
+
+static struct tm *
+gmtsub(struct state const *sp, time_t const *timep, int_fast32_t offset,
+ struct tm *tmp)
+{
+ register struct tm * result;
+
+ result = timesub(timep, offset, gmtptr, tmp);
+#ifdef TM_ZONE
+ /*
+ ** Could get fancy here and deliver something such as
+ ** "+xx" or "-xx" if offset is non-zero,
+ ** but this is no time for a treasure hunt.
+ */
+ tmp->TM_ZONE = ((char *)
+ (offset ? wildabbr : gmtptr ? gmtptr->chars : gmt));
+#endif /* defined TM_ZONE */
+ return result;
+}
+
+/*
+* Re-entrant version of gmtime.
+*/
+
+struct tm *
+gmtime_r(const time_t *timep, struct tm *tmp)
+{
+ gmtcheck();
+ return gmtsub(gmtptr, timep, 0, tmp);
+}
+
+struct tm *
+gmtime(const time_t *timep)
+{
+ return gmtime_r(timep, &tm);
+}
+
+#ifdef STD_INSPIRED
+
+struct tm *
+offtime(const time_t *timep, long offset)
+{
+ gmtcheck();
+ return gmtsub(gmtptr, timep, offset, &tm);
+}
+
+#endif /* defined STD_INSPIRED */
+
+/*
+** Return the number of leap years through the end of the given year
+** where, to make the math easy, the answer for year zero is defined as zero.
+*/
+
+static int
+leaps_thru_end_of_nonneg(int y)
+{
+ return y / 4 - y / 100 + y / 400;
+}
+
+static int
+leaps_thru_end_of(register const int y)
+{
+ return (y < 0
+ ? -1 - leaps_thru_end_of_nonneg(-1 - y)
+ : leaps_thru_end_of_nonneg(y));
+}
+
+static struct tm *
+timesub(const time_t *timep, int_fast32_t offset,
+ const struct state *sp, struct tm *tmp)
+{
+ register const struct lsinfo * lp;
+ register time_t tdays;
+ register int idays; /* unsigned would be so 2003 */
+ register int_fast64_t rem;
+ int y;
+ register const int * ip;
+ register int_fast64_t corr;
+ register bool hit;
+ register int i;
+
+ corr = 0;
+ hit = false;
+ i = (sp == NULL) ? 0 : sp->leapcnt;
+ while (--i >= 0) {
+ lp = &sp->lsis[i];
+ if (*timep >= lp->ls_trans) {
+ corr = lp->ls_corr;
+ hit = (*timep == lp->ls_trans
+ && (i == 0 ? 0 : lp[-1].ls_corr) < corr);
+ break;
+ }
+ }
+ y = EPOCH_YEAR;
+ tdays = *timep / SECSPERDAY;
+ rem = *timep % SECSPERDAY;
+ while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
+ int newy;
+ register time_t tdelta;
+ register int idelta;
+ register int leapdays;
+
+ tdelta = tdays / DAYSPERLYEAR;
+ if (! ((! TYPE_SIGNED(time_t) || INT_MIN <= tdelta)
+ && tdelta <= INT_MAX))
+ goto out_of_range;
+ idelta = tdelta;
+ if (idelta == 0)
+ idelta = (tdays < 0) ? -1 : 1;
+ newy = y;
+ if (increment_overflow(&newy, idelta))
+ goto out_of_range;
+ leapdays = leaps_thru_end_of(newy - 1) -
+ leaps_thru_end_of(y - 1);
+ tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
+ tdays -= leapdays;
+ y = newy;
+ }
+ /*
+ ** Given the range, we can now fearlessly cast...
+ */
+ idays = tdays;
+ rem += offset - corr;
+ while (rem < 0) {
+ rem += SECSPERDAY;
+ --idays;
+ }
+ while (rem >= SECSPERDAY) {
+ rem -= SECSPERDAY;
+ ++idays;
+ }
+ while (idays < 0) {
+ if (increment_overflow(&y, -1))
+ goto out_of_range;
+ idays += year_lengths[isleap(y)];
+ }
+ while (idays >= year_lengths[isleap(y)]) {
+ idays -= year_lengths[isleap(y)];
+ if (increment_overflow(&y, 1))
+ goto out_of_range;
+ }
+ tmp->tm_year = y;
+ if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
+ goto out_of_range;
+ tmp->tm_yday = idays;
+ /*
+ ** The "extra" mods below avoid overflow problems.
+ */
+ tmp->tm_wday = EPOCH_WDAY +
+ ((y - EPOCH_YEAR) % DAYSPERWEEK) *
+ (DAYSPERNYEAR % DAYSPERWEEK) +
+ leaps_thru_end_of(y - 1) -
+ leaps_thru_end_of(EPOCH_YEAR - 1) +
+ idays;
+ tmp->tm_wday %= DAYSPERWEEK;
+ if (tmp->tm_wday < 0)
+ tmp->tm_wday += DAYSPERWEEK;
+ tmp->tm_hour = (int) (rem / SECSPERHOUR);
+ rem %= SECSPERHOUR;
+ tmp->tm_min = (int) (rem / SECSPERMIN);
+ /*
+ ** A positive leap second requires a special
+ ** representation. This uses "... ??:59:60" et seq.
+ */
+ tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
+ ip = mon_lengths[isleap(y)];
+ for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
+ idays -= ip[tmp->tm_mon];
+ tmp->tm_mday = (int) (idays + 1);
+ tmp->tm_isdst = 0;
+#ifdef TM_GMTOFF
+ tmp->TM_GMTOFF = offset;
+#endif /* defined TM_GMTOFF */
+ return tmp;
+
+ out_of_range:
+ errno = EOVERFLOW;
+ return NULL;
+}
+
+char *
+ctime(const time_t *timep)
+{
+/*
+** Section 4.12.3.2 of X3.159-1989 requires that
+** The ctime function converts the calendar time pointed to by timer
+** to local time in the form of a string. It is equivalent to
+** asctime(localtime(timer))
+*/
+ struct tm *tmp = localtime(timep);
+ return tmp ? asctime(tmp) : NULL;
+}
+
+char *
+ctime_r(const time_t *timep, char *buf)
+{
+ struct tm mytm;
+ struct tm *tmp = localtime_r(timep, &mytm);
+ return tmp ? asctime_r(tmp, buf) : NULL;
+}
+
+/*
+** Adapted from code provided by Robert Elz, who writes:
+** The "best" way to do mktime I think is based on an idea of Bob
+** Kridle's (so its said...) from a long time ago.
+** It does a binary search of the time_t space. Since time_t's are
+** just 32 bits, its a max of 32 iterations (even at 64 bits it
+** would still be very reasonable).
+*/
+
+#ifndef WRONG
+#define WRONG (-1)
+#endif /* !defined WRONG */
+
+/*
+** Normalize logic courtesy Paul Eggert.
+*/
+
+static bool
+increment_overflow(int *ip, int j)
+{
+ register int const i = *ip;
+
+ /*
+ ** If i >= 0 there can only be overflow if i + j > INT_MAX
+ ** or if j > INT_MAX - i; given i >= 0, INT_MAX - i cannot overflow.
+ ** If i < 0 there can only be overflow if i + j < INT_MIN
+ ** or if j < INT_MIN - i; given i < 0, INT_MIN - i cannot overflow.
+ */
+ if ((i >= 0) ? (j > INT_MAX - i) : (j < INT_MIN - i))
+ return true;
+ *ip += j;
+ return false;
+}
+
+static bool
+increment_overflow32(int_fast32_t *const lp, int const m)
+{
+ register int_fast32_t const l = *lp;
+
+ if ((l >= 0) ? (m > INT_FAST32_MAX - l) : (m < INT_FAST32_MIN - l))
+ return true;
+ *lp += m;
+ return false;
+}
+
+static bool
+increment_overflow_time(time_t *tp, int_fast32_t j)
+{
+ /*
+ ** This is like
+ ** 'if (! (TIME_T_MIN <= *tp + j && *tp + j <= TIME_T_MAX)) ...',
+ ** except that it does the right thing even if *tp + j would overflow.
+ */
+ if (! (j < 0
+ ? (TYPE_SIGNED(time_t) ? TIME_T_MIN - j <= *tp : -1 - j < *tp)
+ : *tp <= TIME_T_MAX - j))
+ return true;
+ *tp += j;
+ return false;
+}
+
+static bool
+normalize_overflow(int *const tensptr, int *const unitsptr, const int base)
+{
+ register int tensdelta;
+
+ tensdelta = (*unitsptr >= 0) ?
+ (*unitsptr / base) :
+ (-1 - (-1 - *unitsptr) / base);
+ *unitsptr -= tensdelta * base;
+ return increment_overflow(tensptr, tensdelta);
+}
+
+static bool
+normalize_overflow32(int_fast32_t *tensptr, int *unitsptr, int base)
+{
+ register int tensdelta;
+
+ tensdelta = (*unitsptr >= 0) ?
+ (*unitsptr / base) :
+ (-1 - (-1 - *unitsptr) / base);
+ *unitsptr -= tensdelta * base;
+ return increment_overflow32(tensptr, tensdelta);
+}
+
+static int
+tmcomp(register const struct tm *const atmp,
+ register const struct tm *const btmp)
+{
+ register int result;
+
+ if (atmp->tm_year != btmp->tm_year)
+ return atmp->tm_year < btmp->tm_year ? -1 : 1;
+ if ((result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
+ (result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
+ (result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
+ (result = (atmp->tm_min - btmp->tm_min)) == 0)
+ result = atmp->tm_sec - btmp->tm_sec;
+ return result;
+}
+
+static time_t
+time2sub(struct tm *const tmp,
+ struct tm *(*funcp)(struct state const *, time_t const *,
+ int_fast32_t, struct tm *),
+ struct state const *sp,
+ const int_fast32_t offset,
+ bool *okayp,
+ bool do_norm_secs)
+{
+ register int dir;
+ register int i, j;
+ register int saved_seconds;
+ register int_fast32_t li;
+ register time_t lo;
+ register time_t hi;
+ int_fast32_t y;
+ time_t newt;
+ time_t t;
+ struct tm yourtm, mytm;
+
+ *okayp = false;
+ yourtm = *tmp;
+ if (do_norm_secs) {
+ if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
+ SECSPERMIN))
+ return WRONG;
+ }
+ if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
+ return WRONG;
+ if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
+ return WRONG;
+ y = yourtm.tm_year;
+ if (normalize_overflow32(&y, &yourtm.tm_mon, MONSPERYEAR))
+ return WRONG;
+ /*
+ ** Turn y into an actual year number for now.
+ ** It is converted back to an offset from TM_YEAR_BASE later.
+ */
+ if (increment_overflow32(&y, TM_YEAR_BASE))
+ return WRONG;
+ while (yourtm.tm_mday <= 0) {
+ if (increment_overflow32(&y, -1))
+ return WRONG;
+ li = y + (1 < yourtm.tm_mon);
+ yourtm.tm_mday += year_lengths[isleap(li)];
+ }
+ while (yourtm.tm_mday > DAYSPERLYEAR) {
+ li = y + (1 < yourtm.tm_mon);
+ yourtm.tm_mday -= year_lengths[isleap(li)];
+ if (increment_overflow32(&y, 1))
+ return WRONG;
+ }
+ for ( ; ; ) {
+ i = mon_lengths[isleap(y)][yourtm.tm_mon];
+ if (yourtm.tm_mday <= i)
+ break;
+ yourtm.tm_mday -= i;
+ if (++yourtm.tm_mon >= MONSPERYEAR) {
+ yourtm.tm_mon = 0;
+ if (increment_overflow32(&y, 1))
+ return WRONG;
+ }
+ }
+ if (increment_overflow32(&y, -TM_YEAR_BASE))
+ return WRONG;
+ if (! (INT_MIN <= y && y <= INT_MAX))
+ return WRONG;
+ yourtm.tm_year = y;
+ if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
+ saved_seconds = 0;
+ else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
+ /*
+ ** We can't set tm_sec to 0, because that might push the
+ ** time below the minimum representable time.
+ ** Set tm_sec to 59 instead.
+ ** This assumes that the minimum representable time is
+ ** not in the same minute that a leap second was deleted from,
+ ** which is a safer assumption than using 58 would be.
+ */
+ if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
+ return WRONG;
+ saved_seconds = yourtm.tm_sec;
+ yourtm.tm_sec = SECSPERMIN - 1;
+ } else {
+ saved_seconds = yourtm.tm_sec;
+ yourtm.tm_sec = 0;
+ }
+ /*
+ ** Do a binary search (this works whatever time_t's type is).
+ */
+ lo = TIME_T_MIN;
+ hi = TIME_T_MAX;
+ for ( ; ; ) {
+ t = lo / 2 + hi / 2;
+ if (t < lo)
+ t = lo;
+ else if (t > hi)
+ t = hi;
+ if (! funcp(sp, &t, offset, &mytm)) {
+ /*
+ ** Assume that t is too extreme to be represented in
+ ** a struct tm; arrange things so that it is less
+ ** extreme on the next pass.
+ */
+ dir = (t > 0) ? 1 : -1;
+ } else dir = tmcomp(&mytm, &yourtm);
+ if (dir != 0) {
+ if (t == lo) {
+ if (t == TIME_T_MAX)
+ return WRONG;
+ ++t;
+ ++lo;
+ } else if (t == hi) {
+ if (t == TIME_T_MIN)
+ return WRONG;
+ --t;
+ --hi;
+ }
+ if (lo > hi)
+ return WRONG;
+ if (dir > 0)
+ hi = t;
+ else lo = t;
+ continue;
+ }
+#if defined TM_GMTOFF && ! UNINIT_TRAP
+ if (mytm.TM_GMTOFF != yourtm.TM_GMTOFF
+ && (yourtm.TM_GMTOFF < 0
+ ? (-SECSPERDAY <= yourtm.TM_GMTOFF
+ && (mytm.TM_GMTOFF <=
+ (SMALLEST (INT_FAST32_MAX, LONG_MAX)
+ + yourtm.TM_GMTOFF)))
+ : (yourtm.TM_GMTOFF <= SECSPERDAY
+ && ((BIGGEST (INT_FAST32_MIN, LONG_MIN)
+ + yourtm.TM_GMTOFF)
+ <= mytm.TM_GMTOFF)))) {
+ /* MYTM matches YOURTM except with the wrong UT offset.
+ YOURTM.TM_GMTOFF is plausible, so try it instead.
+ It's OK if YOURTM.TM_GMTOFF contains uninitialized data,
+ since the guess gets checked. */
+ time_t altt = t;
+ int_fast32_t diff = mytm.TM_GMTOFF - yourtm.TM_GMTOFF;
+ if (!increment_overflow_time(&altt, diff)) {
+ struct tm alttm;
+ if (funcp(sp, &altt, offset, &alttm)
+ && alttm.tm_isdst == mytm.tm_isdst
+ && alttm.TM_GMTOFF == yourtm.TM_GMTOFF
+ && tmcomp(&alttm, &yourtm) == 0) {
+ t = altt;
+ mytm = alttm;
+ }
+ }
+ }
+#endif
+ if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
+ break;
+ /*
+ ** Right time, wrong type.
+ ** Hunt for right time, right type.
+ ** It's okay to guess wrong since the guess
+ ** gets checked.
+ */
+ if (sp == NULL)
+ return WRONG;
+ for (i = sp->typecnt - 1; i >= 0; --i) {
+ if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
+ continue;
+ for (j = sp->typecnt - 1; j >= 0; --j) {
+ if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
+ continue;
+ newt = t + sp->ttis[j].tt_gmtoff -
+ sp->ttis[i].tt_gmtoff;
+ if (! funcp(sp, &newt, offset, &mytm))
+ continue;
+ if (tmcomp(&mytm, &yourtm) != 0)
+ continue;
+ if (mytm.tm_isdst != yourtm.tm_isdst)
+ continue;
+ /*
+ ** We have a match.
+ */
+ t = newt;
+ goto label;
+ }
+ }
+ return WRONG;
+ }
+label:
+ newt = t + saved_seconds;
+ if ((newt < t) != (saved_seconds < 0))
+ return WRONG;
+ t = newt;
+ if (funcp(sp, &t, offset, tmp))
+ *okayp = true;
+ return t;
+}
+
+static time_t
+time2(struct tm * const tmp,
+ struct tm *(*funcp)(struct state const *, time_t const *,
+ int_fast32_t, struct tm *),
+ struct state const *sp,
+ const int_fast32_t offset,
+ bool *okayp)
+{
+ time_t t;
+
+ /*
+ ** First try without normalization of seconds
+ ** (in case tm_sec contains a value associated with a leap second).
+ ** If that fails, try with normalization of seconds.
+ */
+ t = time2sub(tmp, funcp, sp, offset, okayp, false);
+ return *okayp ? t : time2sub(tmp, funcp, sp, offset, okayp, true);
+}
+
+static time_t
+time1(struct tm *const tmp,
+ struct tm *(*funcp) (struct state const *, time_t const *,
+ int_fast32_t, struct tm *),
+ struct state const *sp,
+ const int_fast32_t offset)
+{
+ register time_t t;
+ register int samei, otheri;
+ register int sameind, otherind;
+ register int i;
+ register int nseen;
+ char seen[TZ_MAX_TYPES];
+ unsigned char types[TZ_MAX_TYPES];
+ bool okay;
+
+ if (tmp == NULL) {
+ errno = EINVAL;
+ return WRONG;
+ }
+ if (tmp->tm_isdst > 1)
+ tmp->tm_isdst = 1;
+ t = time2(tmp, funcp, sp, offset, &okay);
+ if (okay)
+ return t;
+ if (tmp->tm_isdst < 0)
+#ifdef PCTS
+ /*
+ ** POSIX Conformance Test Suite code courtesy Grant Sullivan.
+ */
+ tmp->tm_isdst = 0; /* reset to std and try again */
+#else
+ return t;
+#endif /* !defined PCTS */
+ /*
+ ** We're supposed to assume that somebody took a time of one type
+ ** and did some math on it that yielded a "struct tm" that's bad.
+ ** We try to divine the type they started from and adjust to the
+ ** type they need.
+ */
+ if (sp == NULL)
+ return WRONG;
+ for (i = 0; i < sp->typecnt; ++i)
+ seen[i] = false;
+ nseen = 0;
+ for (i = sp->timecnt - 1; i >= 0; --i)
+ if (!seen[sp->types[i]]) {
+ seen[sp->types[i]] = true;
+ types[nseen++] = sp->types[i];
+ }
+ for (sameind = 0; sameind < nseen; ++sameind) {
+ samei = types[sameind];
+ if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
+ continue;
+ for (otherind = 0; otherind < nseen; ++otherind) {
+ otheri = types[otherind];
+ if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
+ continue;
+ tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
+ sp->ttis[samei].tt_gmtoff;
+ tmp->tm_isdst = !tmp->tm_isdst;
+ t = time2(tmp, funcp, sp, offset, &okay);
+ if (okay)
+ return t;
+ tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
+ sp->ttis[samei].tt_gmtoff;
+ tmp->tm_isdst = !tmp->tm_isdst;
+ }
+ }
+ return WRONG;
+}
+
+static time_t
+mktime_tzname(struct state *sp, struct tm *tmp, bool setname)
+{
+ if (sp)
+ return time1(tmp, localsub, sp, setname);
+ else {
+ gmtcheck();
+ return time1(tmp, gmtsub, gmtptr, 0);
+ }
+}
+
+#if NETBSD_INSPIRED
+
+time_t
+mktime_z(struct state *sp, struct tm *tmp)
+{
+ return mktime_tzname(sp, tmp, false);
+}
+
+#endif
+
+time_t
+mktime(struct tm *tmp)
+{
+ time_t t;
+ int err = lock();
+ if (err) {
+ errno = err;
+ return -1;
+ }
+ tzset_unlocked();
+ t = mktime_tzname(lclptr, tmp, true);
+ unlock();
+ return t;
+}
+
+#ifdef STD_INSPIRED
+
+time_t
+timelocal(struct tm *tmp)
+{
+ if (tmp != NULL)
+ tmp->tm_isdst = -1; /* in case it wasn't initialized */
+ return mktime(tmp);
+}
+
+time_t
+timegm(struct tm *tmp)
+{
+ return timeoff(tmp, 0);
+}
+
+time_t
+timeoff(struct tm *tmp, long offset)
+{
+ if (tmp)
+ tmp->tm_isdst = 0;
+ gmtcheck();
+ return time1(tmp, gmtsub, gmtptr, offset);
+}
+
+#endif /* defined STD_INSPIRED */
+
+/*
+** XXX--is the below the right way to conditionalize??
+*/
+
+#ifdef STD_INSPIRED
+
+/*
+** IEEE Std 1003.1 (POSIX) says that 536457599
+** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
+** is not the case if we are accounting for leap seconds.
+** So, we provide the following conversion routines for use
+** when exchanging timestamps with POSIX conforming systems.
+*/
+
+static int_fast64_t
+leapcorr(struct state const *sp, time_t t)
+{
+ register struct lsinfo const * lp;
+ register int i;
+
+ i = sp->leapcnt;
+ while (--i >= 0) {
+ lp = &sp->lsis[i];
+ if (t >= lp->ls_trans)
+ return lp->ls_corr;
+ }
+ return 0;
+}
+
+NETBSD_INSPIRED_EXTERN time_t
+time2posix_z(struct state *sp, time_t t)
+{
+ return t - leapcorr(sp, t);
+}
+
+time_t
+time2posix(time_t t)
+{
+ int err = lock();
+ if (err) {
+ errno = err;
+ return -1;
+ }
+ if (!lcl_is_set)
+ tzset_unlocked();
+ if (lclptr)
+ t = time2posix_z(lclptr, t);
+ unlock();
+ return t;
+}
+
+NETBSD_INSPIRED_EXTERN time_t
+posix2time_z(struct state *sp, time_t t)
+{
+ time_t x;
+ time_t y;
+ /*
+ ** For a positive leap second hit, the result
+ ** is not unique. For a negative leap second
+ ** hit, the corresponding time doesn't exist,
+ ** so we return an adjacent second.
+ */
+ x = t + leapcorr(sp, t);
+ y = x - leapcorr(sp, x);
+ if (y < t) {
+ do {
+ x++;
+ y = x - leapcorr(sp, x);
+ } while (y < t);
+ x -= y != t;
+ } else if (y > t) {
+ do {
+ --x;
+ y = x - leapcorr(sp, x);
+ } while (y > t);
+ x += y != t;
+ }
+ return x;
+}
+
+time_t
+posix2time(time_t t)
+{
+ int err = lock();
+ if (err) {
+ errno = err;
+ return -1;
+ }
+ if (!lcl_is_set)
+ tzset_unlocked();
+ if (lclptr)
+ t = posix2time_z(lclptr, t);
+ unlock();
+ return t;
+}
+
+#endif /* defined STD_INSPIRED */
+
+#if TZ_TIME_T
+
+# if !USG_COMPAT
+# define daylight 0
+# define timezone 0
+# endif
+# ifndef ALTZONE
+# define altzone 0
+# endif
+
+/* Convert from the underlying system's time_t to the ersatz time_tz,
+ which is called 'time_t' in this file. Typically, this merely
+ converts the time's integer width. On some platforms, the system
+ time is local time not UT, or uses some epoch other than the POSIX
+ epoch.
+
+ Although this code appears to define a function named 'time' that
+ returns time_t, the macros in private.h cause this code to actually
+ define a function named 'tz_time' that returns tz_time_t. The call
+ to sys_time invokes the underlying system's 'time' function. */
+
+time_t
+time(time_t *p)
+{
+ time_t r = sys_time(0);
+ if (r != (time_t) -1) {
+ int_fast32_t offset = EPOCH_LOCAL ? (daylight ? timezone : altzone) : 0;
+ if (increment_overflow32(&offset, -EPOCH_OFFSET)
+ || increment_overflow_time (&r, offset)) {
+ errno = EOVERFLOW;
+ r = -1;
+ }
+ }
+ if (p)
+ *p = r;
+ return r;
+}
+
+#endif
diff --git a/newctime.3 b/newctime.3
new file mode 100644
index 000000000000..d4645adee62f
--- /dev/null
+++ b/newctime.3
@@ -0,0 +1,317 @@
+.TH NEWCTIME 3
+.SH NAME
+asctime, ctime, difftime, gmtime, localtime, mktime \- convert date and time
+.SH SYNOPSIS
+.nf
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.B #include <time.h>
+.PP
+.BR "extern char *tzname[];" " /\(** (optional) \(**/"
+.PP
+.B char *ctime(time_t const *clock);
+.PP
+.B char *ctime_r(time_t const *clock, char *buf);
+.PP
+.B double difftime(time_t time1, time_t time0);
+.PP
+.B char *asctime(struct tm const *tm);
+.PP
+.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
+.fi
+.SH DESCRIPTION
+.ie '\(en'' .ds en \-
+.el .ds en \(en
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+.I Ctime
+converts a long integer, pointed to by
+.IR clock ,
+and returns 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.
+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
+timestamp represents the time in seconds since 1970-01-01 00:00:00
+Coordinated Universal Time (UTC).
+The POSIX standard says that timestamps must be nonnegative
+and must ignore leap seconds.
+Many implementations extend POSIX by allowing negative timestamps,
+and can therefore represent timestamps that predate the
+introduction of UTC and are some other flavor of Universal Time (UT).
+Some implementations support leap seconds, in contradiction to POSIX.
+.PP
+.I Localtime
+and
+.I gmtime
+return pointers to
+.q "tm"
+structures, described below.
+.I Localtime
+corrects for the time zone and any time zone adjustments
+(such as Daylight Saving Time in the United States).
+After filling in the
+.q "tm"
+structure,
+.I localtime
+sets the
+.BR tm_isdst 'th
+element of
+.B tzname
+to a pointer to a string that's the time zone abbreviation to be used with
+.IR localtime 's
+return value.
+.PP
+.I Gmtime
+converts to Coordinated Universal Time.
+.PP
+.I Asctime
+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.
+.PP
+.I Mktime
+converts the broken-down time,
+expressed as local time,
+in the structure pointed to by
+.I tm
+into a calendar time value with the same encoding as that of the values
+returned by the
+.I time
+function.
+The original values of the
+.B tm_wday
+and
+.B tm_yday
+components of the structure are ignored,
+and the original values of the other components are not restricted
+to their normal ranges.
+(A positive or zero value for
+.B tm_isdst
+causes
+.I mktime
+to presume initially that daylight saving time
+respectively,
+is or is not in effect for the specified time.
+A negative value for
+.B tm_isdst
+causes the
+.I mktime
+function to attempt to divine whether daylight saving time is in effect
+for the specified time; in this case it does not use a consistent
+rule and may give a different answer when later
+presented with the same argument.)
+On successful completion, the values of the
+.B tm_wday
+and
+.B tm_yday
+components of the structure are set appropriately,
+and the other components are set to represent the specified calendar time,
+but with their values forced to their normal ranges; the final value of
+.B tm_mday
+is not set until
+.B tm_mon
+and
+.B tm_year
+are determined.
+.I Mktime
+returns the specified calendar time;
+If the calendar time cannot be represented,
+it returns \-1.
+.PP
+.I Difftime
+returns the difference between two calendar times,
+.RI ( time1
+\-
+.IR time0 ),
+expressed in seconds.
+.PP
+.IR Ctime_r ,
+.IR localtime_r ,
+.IR gmtime_r ,
+and
+.I asctime_r
+are like their unsuffixed counterparts, except that they accept an
+additional argument specifying where to store the result if successful.
+.PP
+.IR Localtime_rz
+and
+.I mktime_z
+are like their unsuffixed counterparts, except that they accept an
+extra initial
+.B zone
+argument specifying the time zone to be used for conversion.
+If
+.B zone
+is null, UT is used; otherwise,
+.B zone
+should be have been allocated by
+.I tzalloc
+and should not be freed until after all uses (e.g., by calls to
+.IR strftime )
+of the filled-in
+.B tm_zone
+fields.
+.PP
+Declarations of all the functions and externals, and the
+.q "tm"
+structure,
+are in the
+.B <time.h>
+header file.
+The structure (of type)
+.B struct tm
+includes the following fields:
+.RS
+.PP
+.nf
+.ta 2n +\w'long tm_gmtoff;nn'u
+ int tm_sec; /\(** seconds (0\*(en60) \(**/
+ int tm_min; /\(** minutes (0\*(en59) \(**/
+ int tm_hour; /\(** hours (0\*(en23) \(**/
+ int tm_mday; /\(** day of month (1\*(en31) \(**/
+ int tm_mon; /\(** month of year (0\*(en11) \(**/
+ int tm_year; /\(** year \- 1900 \(**/
+ int tm_wday; /\(** day of week (Sunday = 0) \(**/
+ int tm_yday; /\(** day of year (0\*(en365) \(**/
+ int tm_isdst; /\(** is daylight saving time in effect? \(**/
+ char \(**tm_zone; /\(** time zone abbreviation (optional) \(**/
+ long tm_gmtoff; /\(** offset from UT in seconds (optional) \(**/
+.fi
+.RE
+.PP
+.I Tm_isdst
+is non-zero if daylight saving time is in effect.
+.PP
+.I Tm_gmtoff
+is the offset (in seconds) of the time represented
+from UT, with positive values indicating east
+of the Prime Meridian.
+The field's name is derived from Greenwich Mean Time, a precursor of UT.
+.PP
+In
+.B struct tm
+the
+.I tm_zone
+and
+.I tm_gmtoff
+fields exist, and are filled in, only if arrangements to do
+so were made when the library containing these functions was
+created.
+Similarly, the
+.B tzname
+variable is optional.
+There is no guarantee that these fields and this variable will
+continue to exist in this form in future releases of this code.
+.SH FILES
+.ta \w'/usr/share/zoneinfo/posixrules\0\0'u
+/usr/share/zoneinfo time zone information directory
+.br
+/usr/share/zoneinfo/localtime local time zone file
+.br
+/usr/share/zoneinfo/posixrules used with POSIX-style TZ's
+.br
+/usr/share/zoneinfo/GMT for UTC leap seconds
+.sp
+If
+.B /usr/share/zoneinfo/GMT
+is absent,
+UTC leap seconds are loaded from
+.BR /usr/share/zoneinfo/posixrules .
+.SH SEE ALSO
+getenv(3),
+newstrftime(3),
+newtzset(3),
+time(2),
+tzfile(5)
+.SH NOTES
+The return values of
+.IR asctime ,
+.IR ctime ,
+.IR gmtime ,
+and
+.I localtime
+point to static data
+overwritten by each call.
+The
+.B tzname
+variable (once set) and the
+.B tm_zone
+field of a returned
+.B "struct tm"
+both point to an array of characters that
+can be freed or overwritten by later calls to the functions
+.IR localtime ,
+.IR tzfree ,
+and
+.IR tzset ,
+if these functions affect the time zone information that specifies the
+abbreviation in question.
+The remaining functions and data are thread-safe.
+.PP
+.IR Asctime ,
+.IR asctime_r ,
+.IR ctime ,
+and
+.I ctime_r
+behave strangely for years before 1000 or after 9999.
+The 1989 and 1999 editions of the C Standard say
+that years from \-99 through 999 are converted without
+extra spaces, but this conflicts with longstanding
+tradition and with this implementation.
+The 2011 edition says that the behavior
+is undefined if the year is before 1000 or after 9999.
+Traditional implementations of these two functions are
+restricted to years in the range 1900 through 2099.
+To avoid this portability mess, new programs should use
+.I strftime
+instead.
+.\" This file is in the public domain, so clarified as of
+.\" 2009-05-17 by Arthur David Olson.
diff --git a/newctime.3.txt b/newctime.3.txt
new file mode 100644
index 000000000000..2957a6ce9355
--- /dev/null
+++ b/newctime.3.txt
@@ -0,0 +1,171 @@
+NEWCTIME(3) Library Functions Manual NEWCTIME(3)
+
+NAME
+ asctime, ctime, difftime, gmtime, localtime, mktime - convert date and
+ time
+
+SYNOPSIS
+ #include <time.h>
+
+ extern char *tzname[]; /* (optional) */
+
+ char *ctime(time_t const *clock);
+
+ char *ctime_r(time_t const *clock, char *buf);
+
+ double difftime(time_t time1, time_t time0);
+
+ char *asctime(struct tm const *tm);
+
+ char *asctime_r(struct tm const *restrict tm,
+ char *restrict result);
+
+ struct tm *localtime(time_t const *clock);
+
+ struct tm *localtime_r(time_t const *restrict clock,
+ struct tm *restrict result);
+
+ struct tm *localtime_rz(timezone_t restrict zone,
+ time_t const *restrict clock,
+ struct tm *restrict result);
+
+ struct tm *gmtime(time_t const *clock);
+
+ struct tm *gmtime_r(time_t const *restrict clock,
+ struct tm *restrict result);
+
+ time_t mktime(struct tm *tm);
+
+ time_t mktime_z(timezone_t restrict zone,
+ struct tm *restrict tm);
+
+ cc ... -ltz
+
+DESCRIPTION
+ Ctime converts a long integer, pointed to by clock, and returns a
+ pointer to a string of the form
+ Thu Nov 24 18:22:48 1986\n\0
+ Years requiring fewer than four characters are padded with leading
+ zeroes. For years longer than four characters, the string is of the
+ form
+ Thu Nov 24 18:22:48 81986\n\0
+ 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.
+
+ The *clock timestamp represents the time in seconds since 1970-01-01
+ 00:00:00 Coordinated Universal Time (UTC). The POSIX standard says
+ that timestamps must be nonnegative and must ignore leap seconds. Many
+ implementations extend POSIX by allowing negative timestamps, and can
+ therefore represent timestamps that predate the introduction of UTC and
+ are some other flavor of Universal Time (UT). Some implementations
+ support leap seconds, in contradiction to POSIX.
+
+ Localtime and gmtime return pointers to "tm" structures, described
+ below. Localtime corrects for the time zone and any time zone
+ adjustments (such as Daylight Saving Time in the United States). After
+ filling in the "tm" structure, localtime sets the tm_isdst'th element
+ of tzname to a pointer to a string that's the time zone abbreviation to
+ be used with localtime's return value.
+
+ Gmtime converts to Coordinated Universal Time.
+
+ Asctime converts a time value contained in a "tm" structure to a
+ string, as shown in the above example, and returns a pointer to the
+ string.
+
+ Mktime converts the broken-down time, expressed as local time, in the
+ structure pointed to by tm into a calendar time value with the same
+ encoding as that of the values returned by the time function. The
+ original values of the tm_wday and tm_yday components of the structure
+ are ignored, and the original values of the other components are not
+ restricted to their normal ranges. (A positive or zero value for
+ tm_isdst causes mktime to presume initially that daylight saving time
+ respectively, is or is not in effect for the specified time. A
+ negative value for tm_isdst causes the mktime function to attempt to
+ divine whether daylight saving time is in effect for the specified
+ time; in this case it does not use a consistent rule and may give a
+ different answer when later presented with the same argument.) On
+ successful completion, the values of the tm_wday and tm_yday components
+ of the structure are set appropriately, and the other components are
+ set to represent the specified calendar time, but with their values
+ forced to their normal ranges; the final value of tm_mday is not set
+ until tm_mon and tm_year are determined. Mktime returns the specified
+ calendar time; If the calendar time cannot be represented, it returns
+ -1.
+
+ Difftime returns the difference between two calendar times, (time1 -
+ time0), expressed in seconds.
+
+ Ctime_r, localtime_r, gmtime_r, and asctime_r are like their unsuffixed
+ counterparts, except that they accept an additional argument specifying
+ where to store the result if successful.
+
+ Localtime_rz and mktime_z are like their unsuffixed counterparts,
+ except that they accept an extra initial zone argument specifying the
+ time zone to be used for conversion. If zone is null, UT is used;
+ otherwise, zone should be have been allocated by tzalloc and should not
+ be freed until after all uses (e.g., by calls to strftime) of the
+ filled-in tm_zone fields.
+
+ Declarations of all the functions and externals, and the "tm"
+ structure, are in the <time.h> header file. The structure (of type)
+ struct tm includes the following fields:
+
+ int tm_sec; /* seconds (0-60) */
+ int tm_min; /* minutes (0-59) */
+ int tm_hour; /* hours (0-23) */
+ int tm_mday; /* day of month (1-31) */
+ int tm_mon; /* month of year (0-11) */
+ int tm_year; /* year - 1900 */
+ int tm_wday; /* day of week (Sunday = 0) */
+ int tm_yday; /* day of year (0-365) */
+ int tm_isdst; /* is daylight saving time in effect? */
+ char *tm_zone; /* time zone abbreviation (optional) */
+ long tm_gmtoff; /* offset from UT in seconds (optional) */
+
+ Tm_isdst is non-zero if daylight saving time is in effect.
+
+ Tm_gmtoff is the offset (in seconds) of the time represented from UT,
+ with positive values indicating east of the Prime Meridian. The
+ field's name is derived from Greenwich Mean Time, a precursor of UT.
+
+ In struct tm the tm_zone and tm_gmtoff fields exist, and are filled in,
+ only if arrangements to do so were made when the library containing
+ these functions was created. Similarly, the tzname variable is
+ optional. There is no guarantee that these fields and this variable
+ will continue to exist in this form in future releases of this code.
+
+FILES
+ /usr/share/zoneinfo time zone information directory
+ /usr/share/zoneinfo/localtime local time zone file
+ /usr/share/zoneinfo/posixrules used with POSIX-style TZ's
+ /usr/share/zoneinfo/GMT for UTC leap seconds
+
+ If /usr/share/zoneinfo/GMT is absent, UTC leap seconds are loaded from
+ /usr/share/zoneinfo/posixrules.
+
+SEE ALSO
+ getenv(3), newstrftime(3), newtzset(3), time(2), tzfile(5)
+
+NOTES
+ The return values of asctime, ctime, gmtime, and localtime point to
+ static data overwritten by each call. The tzname variable (once set)
+ and the tm_zone field of a returned struct tm both point to an array of
+ characters that can be freed or overwritten by later calls to the
+ functions localtime, tzfree, and tzset, if these functions affect the
+ time zone information that specifies the abbreviation in question. The
+ remaining functions and data are thread-safe.
+
+ Asctime, asctime_r, ctime, and ctime_r behave strangely for years
+ before 1000 or after 9999. The 1989 and 1999 editions of the C
+ Standard say that years from -99 through 999 are converted without
+ extra spaces, but this conflicts with longstanding tradition and with
+ this implementation. The 2011 edition says that the behavior is
+ undefined if the year is before 1000 or after 9999. Traditional
+ implementations of these two functions are restricted to years in the
+ range 1900 through 2099. To avoid this portability mess, new programs
+ should use strftime instead.
+
+ NEWCTIME(3)
diff --git a/newstrftime.3 b/newstrftime.3
new file mode 100644
index 000000000000..f1a1a6d7c1cd
--- /dev/null
+++ b/newstrftime.3
@@ -0,0 +1,238 @@
+.\" Based on the UCB file whose corrected copyright information appears below.
+.\" Copyright 1989, 1991 The Regents of the University of California.
+.\" All rights reserved.
+.\"
+.\" This code is derived from software contributed to Berkeley by
+.\" the American National Standards Committee X3, on Information
+.\" Processing Systems.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. Neither the name of the University nor the names of its contributors
+.\" may be used to endorse or promote products derived from this software
+.\" without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" from: @(#)strftime.3 5.12 (Berkeley) 6/29/91
+.\" $Id: strftime.3,v 1.4 1993/12/15 20:33:00 jtc Exp $
+.\"
+.TH NEWSTRFTIME 3
+.SH NAME
+strftime \- format date and time
+.SH SYNOPSIS
+.nf
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.B #include <time.h>
+.PP
+.B "size_t strftime(char *restrict buf, size_t maxsize,"
+.B " char const *restrict format, struct tm const *restrict timeptr);"
+.PP
+.B cc ... \-ltz
+.fi
+.SH DESCRIPTION
+.ie '\(en'' .ds en \-
+.el .ds en \(en
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+The
+.I strftime
+function formats the information from
+.I timeptr
+into the buffer
+.I buf
+according to the string pointed to by
+.IR format .
+.PP
+The
+.I format
+string consists of zero or more conversion specifications and
+ordinary characters.
+All ordinary characters are copied directly into the buffer.
+A conversion specification consists of a percent sign
+.Ql %
+and one other character.
+.PP
+No more than
+.I maxsize
+characters are placed into the array.
+If the total number of resulting characters, including the terminating
+null character, is not more than
+.IR maxsize ,
+.I strftime
+returns the number of characters in the array, not counting the
+terminating null.
+Otherwise, zero is returned.
+.PP
+Each conversion specification is replaced by the characters as
+follows which are then copied into the buffer.
+.TP
+%A
+is replaced by the locale's full weekday name.
+.TP
+%a
+is replaced by the locale's abbreviated weekday name.
+.TP
+%B
+is replaced by the locale's full month name.
+.TP
+%b or %h
+is replaced by the locale's abbreviated month name.
+.TP
+%C
+is replaced by the century (a year divided by 100 and truncated to an integer)
+as a decimal number (00\*(en99).
+.TP
+%c
+is replaced by the locale's appropriate date and time representation.
+.TP
+%D
+is replaced by the date in the format %m/%d/%y.
+.TP
+%d
+is replaced by the day of the month as a decimal number (01\*(en31).
+.TP
+%e
+is replaced by the day of month as a decimal number (1\*(en31);
+single digits are preceded by a blank.
+.TP
+%F
+is replaced by the date in the format %Y\*-%m\*-%d.
+.TP
+%G
+is replaced by the ISO 8601 year with century as a decimal number.
+.TP
+%g
+is replaced by the ISO 8601 year without century as a decimal number (00\*(en99).
+.TP
+%H
+is replaced by the hour (24-hour clock) as a decimal number (00\*(en23).
+.TP
+%I
+is replaced by the hour (12-hour clock) as a decimal number (01\*(en12).
+.TP
+%j
+is replaced by the day of the year as a decimal number (001\*(en366).
+.TP
+%k
+is replaced by the hour (24-hour clock) as a decimal number (0\*(en23);
+single digits are preceded by a blank.
+.TP
+%l
+is replaced by the hour (12-hour clock) as a decimal number (1\*(en12);
+single digits are preceded by a blank.
+.TP
+%M
+is replaced by the minute as a decimal number (00\*(en59).
+.TP
+%m
+is replaced by the month as a decimal number (01\*(en12).
+.TP
+%n
+is replaced by a newline.
+.TP
+%p
+is replaced by the locale's equivalent of either AM or PM.
+.TP
+%R
+is replaced by the time in the format %H:%M.
+.TP
+%r
+is replaced by the locale's representation of 12-hour clock time
+using AM/PM notation.
+.TP
+%S
+is replaced by the second as a decimal number (00\*(en60).
+.TP
+%s
+is replaced by the number of seconds since the Epoch (see newctime(3)).
+.TP
+%T
+is replaced by the time in the format %H:%M:%S.
+.TP
+%t
+is replaced by a tab.
+.TP
+%U
+is replaced by the week number of the year (Sunday as the first day of
+the week) as a decimal number (00\*(en53).
+.TP
+%u
+is replaced by the weekday (Monday as the first day of the week)
+as a decimal number (1\*(en7).
+.TP
+%V
+is replaced by the week number of the year (Monday as the first day of
+the week) as a decimal number (01\*(en53). If the week containing January
+1 has four or more days in the new year, then it is week 1; otherwise
+it is week 53 of the previous year, and the next week is week 1.
+.TP
+%W
+is replaced by the week number of the year (Monday as the first day of
+the week) as a decimal number (00\*(en53).
+.TP
+%w
+is replaced by the weekday (Sunday as the first day of the week)
+as a decimal number (0\*(en6).
+.TP
+%X
+is replaced by the locale's appropriate time representation.
+.TP
+%x
+is replaced by the locale's appropriate date representation.
+.TP
+%Y
+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\*(en99).
+.TP
+%Z
+is replaced by the time zone name,
+or by the empty string if this is not determinable.
+.TP
+%z
+is replaced by the offset from the Prime Meridian
+in the format +HHMM or \*-HHMM as appropriate,
+with positive values representing locations east of Greenwich,
+or by the empty string if this is not determinable.
+The numeric time zone \*-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 "\*-" .
+.TP
+%%
+is replaced by a single %.
+.TP
+%+
+is replaced by the date and time in date(1) format.
+.SH SEE ALSO
+date(1),
+getenv(3),
+newctime(3),
+newtzset(3),
+time(2),
+tzfile(5)
diff --git a/newstrftime.3.txt b/newstrftime.3.txt
new file mode 100644
index 000000000000..52daff142abf
--- /dev/null
+++ b/newstrftime.3.txt
@@ -0,0 +1,145 @@
+NEWSTRFTIME(3) Library Functions Manual NEWSTRFTIME(3)
+
+NAME
+ strftime - format date and time
+
+SYNOPSIS
+ #include <time.h>
+
+ size_t strftime(char *restrict buf, size_t maxsize,
+ char const *restrict format, struct tm const *restrict timeptr);
+
+ cc ... -ltz
+
+DESCRIPTION
+ The strftime function formats the information from timeptr into the
+ buffer buf according to the string pointed to by format.
+
+ The format string consists of zero or more conversion specifications
+ and ordinary characters. All ordinary characters are copied directly
+ into the buffer. A conversion specification consists of a percent sign
+ and one other character.
+
+ No more than maxsize characters are placed into the array. If the
+ total number of resulting characters, including the terminating null
+ character, is not more than maxsize, strftime returns the number of
+ characters in the array, not counting the terminating null. Otherwise,
+ zero is returned.
+
+ Each conversion specification is replaced by the characters as follows
+ which are then copied into the buffer.
+
+ %A is replaced by the locale's full weekday name.
+
+ %a is replaced by the locale's abbreviated weekday name.
+
+ %B is replaced by the locale's full month name.
+
+ %b or %h
+ is replaced by the locale's abbreviated month name.
+
+ %C is replaced by the century (a year divided by 100 and truncated
+ to an integer) as a decimal number (00-99).
+
+ %c is replaced by the locale's appropriate date and time
+ representation.
+
+ %D is replaced by the date in the format %m/%d/%y.
+
+ %d is replaced by the day of the month as a decimal number (01-31).
+
+ %e is replaced by the day of month as a decimal number (1-31);
+ single digits are preceded by a blank.
+
+ %F is replaced by the date in the format %Y-%m-%d.
+
+ %G is replaced by the ISO 8601 year with century as a decimal
+ number.
+
+ %g is replaced by the ISO 8601 year without century as a decimal
+ number (00-99).
+
+ %H is replaced by the hour (24-hour clock) as a decimal number
+ (00-23).
+
+ %I is replaced by the hour (12-hour clock) as a decimal number
+ (01-12).
+
+ %j is replaced by the day of the year as a decimal number
+ (001-366).
+
+ %k is replaced by the hour (24-hour clock) as a decimal number
+ (0-23); single digits are preceded by a blank.
+
+ %l is replaced by the hour (12-hour clock) as a decimal number
+ (1-12); single digits are preceded by a blank.
+
+ %M is replaced by the minute as a decimal number (00-59).
+
+ %m is replaced by the month as a decimal number (01-12).
+
+ %n is replaced by a newline.
+
+ %p is replaced by the locale's equivalent of either AM or PM.
+
+ %R is replaced by the time in the format %H:%M.
+
+ %r is replaced by the locale's representation of 12-hour clock time
+ using AM/PM notation.
+
+ %S is replaced by the second as a decimal number (00-60).
+
+ %s is replaced by the number of seconds since the Epoch (see
+ newctime(3)).
+
+ %T is replaced by the time in the format %H:%M:%S.
+
+ %t is replaced by a tab.
+
+ %U is replaced by the week number of the year (Sunday as the first
+ day of the week) as a decimal number (00-53).
+
+ %u is replaced by the weekday (Monday as the first day of the week)
+ as a decimal number (1-7).
+
+ %V is replaced by the week number of the year (Monday as the first
+ day of the week) as a decimal number (01-53). If the week
+ containing January 1 has four or more days in the new year, then
+ it is week 1; otherwise it is week 53 of the previous year, and
+ the next week is week 1.
+
+ %W is replaced by the week number of the year (Monday as the first
+ day of the week) as a decimal number (00-53).
+
+ %w is replaced by the weekday (Sunday as the first day of the week)
+ as a decimal number (0-6).
+
+ %X is replaced by the locale's appropriate time representation.
+
+ %x is replaced by the locale's appropriate date representation.
+
+ %Y is replaced by the year with century as a decimal number.
+
+ %y is replaced by the year without century as a decimal number
+ (00-99).
+
+ %Z is replaced by the time zone name, or by the empty string if
+ this is not determinable.
+
+ %z is replaced by the offset from the Prime Meridian in the format
+ +HHMM or -HHMM as appropriate, with positive values representing
+ locations east of Greenwich, or by the empty string if this is
+ not determinable. The numeric time zone -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 "-".
+
+ %% is replaced by a single %.
+
+ %+ is replaced by the date and time in date(1) format.
+
+SEE ALSO
+ date(1), getenv(3), newctime(3), newtzset(3), time(2), tzfile(5)
+
+ NEWSTRFTIME(3)
diff --git a/newtzset.3 b/newtzset.3
new file mode 100644
index 000000000000..0eab7327e8f5
--- /dev/null
+++ b/newtzset.3
@@ -0,0 +1,344 @@
+.TH NEWTZSET 3
+.SH NAME
+tzset \- initialize time conversion information
+.SH SYNOPSIS
+.nf
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.B #include <time.h>
+.PP
+.B timezone_t tzalloc(char const *TZ);
+.PP
+.B void tzfree(timezone_t tz);
+.PP
+.B void tzset(void);
+.PP
+.B cc ... \*-ltz
+.fi
+.SH DESCRIPTION
+.ie '\(en'' .ds en \-
+.el .ds en \(en
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+.I Tzalloc
+allocates and returns a time zone object described by
+.BR TZ .
+If
+.B TZ
+is not a valid time zone description, or if the object cannot be allocated,
+.I tzalloc
+returns a null pointer and sets
+.BR errno .
+.PP
+.I Tzfree
+frees a time zone object
+.BR tz ,
+which should have been successfully allocated by
+.IR tzalloc .
+This invalidates any
+.B tm_zone
+pointers that
+.B tz
+was used to set.
+.PP
+.I Tzset
+acts like
+.BR tzalloc(getenv("TZ")) ,
+except it saves any resulting time zone object into internal
+storage that is accessed by
+.IR localtime ,
+.IR localtime_r ,
+and
+.IR mktime .
+The anonymous shared time zone object is freed by the next call to
+.IR tzset .
+If the implied call to
+.B tzalloc
+fails,
+.I tzset
+falls back on Universal Time (UT).
+.PP
+If
+.B TZ
+is null, the best available approximation to local wall
+clock time, as specified by the
+.IR tzfile (5)-format
+file
+.B localtime
+in the system time conversion information directory, is used.
+If
+.B TZ
+is the empty string,
+UT is used, with the abbreviation "UTC"
+and without leap second correction; please see
+.IR newctime (3)
+for more about UT, UTC, and leap seconds. If
+.B TZ
+is nonnull and nonempty:
+.IP
+if the value begins with a colon, it is used as a pathname of a file
+from which to read the time conversion information;
+.IP
+if the value does not begin with a colon, it is first used as the
+pathname of a file from which to read the time conversion information,
+and, if that file cannot be read, is used directly as a specification of
+the time conversion information.
+.PP
+When
+.B TZ
+is used as a pathname, if it begins with a slash,
+it is used as an absolute pathname; otherwise,
+it is used as a pathname relative to a system time conversion information
+directory.
+The file must be in the format specified in
+.IR tzfile (5).
+.PP
+When
+.B TZ
+is used directly as a specification of the time conversion information,
+it must have the following syntax (spaces inserted for clarity):
+.IP
+\fIstd\|offset\fR[\fIdst\fR[\fIoffset\fR][\fB,\fIrule\fR]]
+.PP
+Where:
+.RS
+.TP 15
+.IR std " and " dst
+Three or more bytes that are the designation for the standard
+.RI ( std )
+or the alternative
+.RI ( dst ,
+such as daylight saving time)
+time zone. Only
+.I std
+is required; if
+.I dst
+is missing, then daylight saving time does not apply in this locale.
+Upper- and lowercase letters are explicitly allowed. Any characters
+except a leading colon
+.RB ( : ),
+digits, comma
+.RB ( , ),
+ASCII minus
+.RB ( \*- ),
+ASCII plus
+.RB ( + ),
+and NUL bytes are allowed.
+Alternatively, a designation can be surrounded by angle brackets
+.B <
+and
+.BR > ;
+in this case, the designation can contain any characters other than
+.B >
+and NUL.
+.TP
+.I offset
+Indicates the value one must add to the local time to arrive at
+Coordinated Universal Time. The
+.I offset
+has the form:
+.RS
+.IP
+\fIhh\fR[\fB:\fImm\fR[\fB:\fIss\fR]]
+.RE
+.IP
+The minutes
+.RI ( mm )
+and seconds
+.RI ( ss )
+are optional. The hour
+.RI ( hh )
+is required and may be a single digit. The
+.I offset
+following
+.I std
+is required. If no
+.I offset
+follows
+.IR dst ,
+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 "\*-" ,
+the time zone shall be east of the Prime Meridian; otherwise it shall be
+west (which may be indicated by an optional preceding
+.q "+" .
+.TP
+.I rule
+Indicates when to change to and back from daylight saving time. The
+.I rule
+has the form:
+.RS
+.IP
+\fIdate\fB/\fItime\fB,\fIdate\fB/\fItime\fR
+.RE
+.IP
+where the first
+.I date
+describes when the change from standard to daylight saving time occurs and the
+second
+.I date
+describes when the change back happens. Each
+.I time
+field describes when, in current local time, the change to the other
+time is made.
+As an extension to POSIX, daylight saving is assumed to be in effect
+all year if it begins January 1 at 00:00 and ends December 31 at
+24:00 plus the difference between daylight saving and standard time,
+leaving no room for standard time in the calendar.
+.IP
+The format of
+.I date
+is one of the following:
+.RS
+.TP 10
+.BI J n
+The Julian day
+.I n
+.RI "(1\ \(<=" "\ n\ " "\(<=\ 365).
+Leap days are not counted; that is, in all years \*(en including leap
+years \*(en February 28 is day 59 and March 1 is day 60. It is
+impossible to explicitly refer to the occasional February 29.
+.TP
+.I n
+The zero-based Julian day
+.RI "(0\ \(<=" "\ n\ " "\(<=\ 365).
+Leap days are counted, and it is possible to refer to February 29.
+.TP
+.BI M m . n . d
+The
+.IR d' th
+day
+.RI "(0\ \(<=" "\ d\ " "\(<=\ 6)
+of week
+.I n
+of month
+.I m
+of the year
+.RI "(1\ \(<=" "\ n\ " "\(<=\ 5,
+.RI "1\ \(<=" "\ m\ " "\(<=\ 12,
+where week 5 means
+.q "the last \fId\fP day in month \fIm\fP"
+which may occur in either the fourth or the fifth week). Week 1 is the
+first week in which the
+.IR d' th
+day occurs. Day zero is Sunday.
+.RE
+.IP "" 15
+The
+.I time
+has the same format as
+.I offset
+except that POSIX does not allow a leading sign (\c
+.q "\*-"
+or
+.q "+" ).
+As an extension to POSIX, the hours part of
+.I time
+can range from \-167 through 167; this allows for unusual rules such
+as
+.q "the Saturday before the first Sunday of March" .
+The default, if
+.I time
+is not given, is
+.BR 02:00:00 .
+.RE
+.LP
+Here are some examples of
+.B TZ
+values that directly specify the time zone rules; they use some of the
+extensions to POSIX.
+.TP
+.B EST5
+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
+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
+first Sunday on or after January 14). The abbreviations for standard
+and daylight saving time are
+.q "+12"
+and
+.q "+13".
+.TP
+.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
+stands for permanent daylight saving time, 3 hours behind UT with
+abbreviation
+.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>
+is a placeholder.
+.TP
+.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"
+and
+.q "\*-02".
+.PP
+If no
+.I rule
+is present in
+.BR TZ ,
+the rules specified
+by the
+.IR tzfile (5)-format
+file
+.B posixrules
+in the system time conversion information directory are used, with the
+standard and daylight saving time offsets from UT replaced by those specified by
+the
+.I offset
+values in
+.BR TZ .
+.PP
+For compatibility with System V Release 3.1, a semicolon
+.RB ( ; )
+may be used to separate the
+.I rule
+from the rest of the specification.
+.SH FILES
+.ta \w'/usr/share/zoneinfo/posixrules\0\0'u
+/usr/share/zoneinfo time zone information directory
+.br
+/usr/share/zoneinfo/localtime local time zone file
+.br
+/usr/share/zoneinfo/posixrules used with POSIX-style TZ's
+.br
+/usr/share/zoneinfo/GMT for UTC leap seconds
+.sp
+If
+.B /usr/share/zoneinfo/GMT
+is absent,
+UTC leap seconds are loaded from
+.BR /usr/share/zoneinfo/posixrules .
+.SH SEE ALSO
+getenv(3),
+newctime(3),
+newstrftime(3),
+time(2),
+tzfile(5)
+.\" This file is in the public domain, so clarified as of
+.\" 2009-05-17 by Arthur David Olson.
diff --git a/newtzset.3.txt b/newtzset.3.txt
new file mode 100644
index 000000000000..765e4aaba710
--- /dev/null
+++ b/newtzset.3.txt
@@ -0,0 +1,199 @@
+NEWTZSET(3) Library Functions Manual NEWTZSET(3)
+
+NAME
+ tzset - initialize time conversion information
+
+SYNOPSIS
+ #include <time.h>
+
+ timezone_t tzalloc(char const *TZ);
+
+ void tzfree(timezone_t tz);
+
+ void tzset(void);
+
+ cc ... -ltz
+
+DESCRIPTION
+ Tzalloc allocates and returns a time zone object described by TZ. If
+ TZ is not a valid time zone description, or if the object cannot be
+ allocated, tzalloc returns a null pointer and sets errno.
+
+ Tzfree frees a time zone object tz, which should have been successfully
+ allocated by tzalloc. This invalidates any tm_zone pointers that tz
+ was used to set.
+
+ Tzset acts like tzalloc(getenv("TZ")), except it saves any resulting
+ time zone object into internal storage that is accessed by localtime,
+ localtime_r, and mktime. The anonymous shared time zone object is
+ freed by the next call to tzset. If the implied call to tzalloc fails,
+ tzset falls back on Universal Time (UT).
+
+ If TZ is null, the best available approximation to local wall clock
+ time, as specified by the tzfile(5)-format file localtime in the system
+ time conversion information directory, is used. If TZ is the empty
+ string, UT is used, with the abbreviation "UTC" and without leap second
+ correction; please see newctime(3) for more about UT, UTC, and leap
+ seconds. If TZ is nonnull and nonempty:
+
+ if the value begins with a colon, it is used as a pathname of a
+ file from which to read the time conversion information;
+
+ if the value does not begin with a colon, it is first used as
+ the pathname of a file from which to read the time conversion
+ information, and, if that file cannot be read, is used directly
+ as a specification of the time conversion information.
+
+ When TZ is used as a pathname, if it begins with a slash, it is used as
+ an absolute pathname; otherwise, it is used as a pathname relative to a
+ system time conversion information directory. The file must be in the
+ format specified in tzfile(5).
+
+ When TZ is used directly as a specification of the time conversion
+ information, it must have the following syntax (spaces inserted for
+ clarity):
+
+ stdoffset[dst[offset][,rule]]
+
+ Where:
+
+ std and dst Three or more bytes that are the designation for
+ the standard (std) or the alternative (dst, such
+ as daylight saving time) time zone. Only std is
+ required; if dst is missing, then daylight saving
+ time does not apply in this locale. Upper- and
+ lowercase letters are explicitly allowed. Any
+ characters except a leading colon (:), digits,
+ comma (,), ASCII minus (-), ASCII plus (+), and
+ NUL bytes are allowed. Alternatively, a
+ designation can be surrounded by angle brackets <
+ and >; in this case, the designation can contain
+ any characters other than > and NUL.
+
+ offset Indicates the value one must add to the local
+ time to arrive at Coordinated Universal Time.
+ The offset has the form:
+
+ hh[:mm[:ss]]
+
+ The minutes (mm) and seconds (ss) are optional.
+ The hour (hh) is required and may be a single
+ digit. The offset following std is required. If
+ no offset follows dst, 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) - if present - between zero and 59. If
+ preceded by a "-", the time zone shall be east of
+ the Prime Meridian; otherwise it shall be west
+ (which may be indicated by an optional preceding
+ "+".
+
+ rule Indicates when to change to and back from
+ daylight saving time. The rule has the form:
+
+ date/time,date/time
+
+ where the first date describes when the change
+ from standard to daylight saving time occurs and
+ the second date describes when the change back
+ happens. Each time field describes when, in
+ current local time, the change to the other time
+ is made. As an extension to POSIX, daylight
+ saving is assumed to be in effect all year if it
+ begins January 1 at 00:00 and ends December 31 at
+ 24:00 plus the difference between daylight saving
+ and standard time, leaving no room for standard
+ time in the calendar.
+
+ The format of date is one of the following:
+
+ Jn The Julian day n (1 <= n <= 365). Leap
+ days are not counted; that is, in all
+ years - including leap years - February
+ 28 is day 59 and March 1 is day 60. It
+ is impossible to explicitly refer to
+ the occasional February 29.
+
+ n The zero-based Julian day
+ (0 <= n <= 365). Leap days are
+ counted, and it is possible to refer to
+ February 29.
+
+ Mm.n.d The d'th day (0 <= d <= 6) of week n of
+ month m of the year (1 <= n <= 5,
+ 1 <= m <= 12, where week 5 means "the
+ last d day in month m" which may occur
+ in either the fourth or the fifth
+ week). Week 1 is the first week in
+ which the d'th day occurs. Day zero is
+ Sunday.
+
+ The time has the same format as offset except
+ that POSIX does not allow a leading sign ("-" or
+ "+"). As an extension to POSIX, the hours part
+ of time can range from -167 through 167; this
+ allows for unusual rules such as "the Saturday
+ before the first Sunday of March". The default,
+ if time is not given, is 02:00:00.
+
+ Here are some examples of TZ values that directly specify the time zone
+ rules; they use some of the extensions to POSIX.
+
+ EST5 stands for US Eastern Standard Time (EST), 5 hours behind UT,
+ without daylight saving.
+
+ <+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 first Sunday on or
+ after January 14). The abbreviations for standard and daylight
+ saving time are "+12" and "+13".
+
+ 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.
+
+ <-04>4<-03>,J1/0,J365/25
+ stands for permanent daylight saving time, 3 hours behind UT
+ with abbreviation "-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 <-04> is a placeholder.
+
+ <-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 "-03"
+ and "-02".
+
+ If no rule is present in TZ, the rules specified by the
+ tzfile(5)-format file posixrules in the system time conversion
+ information directory are used, with the standard and daylight saving
+ time offsets from UT replaced by those specified by the offset values
+ in TZ.
+
+ For compatibility with System V Release 3.1, a semicolon (;) may be
+ used to separate the rule from the rest of the specification.
+
+FILES
+ /usr/share/zoneinfo time zone information directory
+ /usr/share/zoneinfo/localtime local time zone file
+ /usr/share/zoneinfo/posixrules used with POSIX-style TZ's
+ /usr/share/zoneinfo/GMT for UTC leap seconds
+
+ If /usr/share/zoneinfo/GMT is absent, UTC leap seconds are loaded from
+ /usr/share/zoneinfo/posixrules.
+
+SEE ALSO
+ getenv(3), newctime(3), newstrftime(3), time(2), tzfile(5)
+
+ NEWTZSET(3)
diff --git a/private.h b/private.h
new file mode 100644
index 000000000000..641f905e4131
--- /dev/null
+++ b/private.h
@@ -0,0 +1,760 @@
+#ifndef PRIVATE_H
+
+#define PRIVATE_H
+
+/*
+** This file is in the public domain, so clarified as of
+** 1996-06-05 by Arthur David Olson.
+*/
+
+/*
+** This header is for use ONLY with the time conversion code.
+** There is no guarantee that it will remain unchanged,
+** or that it will remain at all.
+** Do NOT copy it to any system include directory.
+** Thank you!
+*/
+
+/*
+** zdump has been made independent of the rest of the time
+** conversion package to increase confidence in the verification it provides.
+** You can use zdump to help in verifying other implementations.
+** To do this, compile with -DUSE_LTZ=0 and link without the tz library.
+*/
+#ifndef USE_LTZ
+# define USE_LTZ 1
+#endif
+
+/* This string was in the Factory zone through version 2016f. */
+#define GRANDPARENTED "Local time zone must be set--see zic manual page"
+
+/*
+** Defaults for preprocessor symbols.
+** You can override these in your C compiler options, e.g. '-DHAVE_GETTEXT=1'.
+*/
+
+#ifndef HAVE_DECL_ASCTIME_R
+#define HAVE_DECL_ASCTIME_R 1
+#endif
+
+#if !defined HAVE_GENERIC && defined __has_extension
+# if __has_extension(c_generic_selections)
+# define HAVE_GENERIC 1
+# else
+# define HAVE_GENERIC 0
+# endif
+#endif
+/* _Generic is buggy in pre-4.9 GCC. */
+#if !defined HAVE_GENERIC && defined __GNUC__
+# define HAVE_GENERIC (4 < __GNUC__ + (9 <= __GNUC_MINOR__))
+#endif
+#ifndef HAVE_GENERIC
+# define HAVE_GENERIC (201112 <= __STDC_VERSION__)
+#endif
+
+#ifndef HAVE_GETTEXT
+#define HAVE_GETTEXT 0
+#endif /* !defined HAVE_GETTEXT */
+
+#ifndef HAVE_INCOMPATIBLE_CTIME_R
+#define HAVE_INCOMPATIBLE_CTIME_R 0
+#endif
+
+#ifndef HAVE_LINK
+#define HAVE_LINK 1
+#endif /* !defined HAVE_LINK */
+
+#ifndef HAVE_POSIX_DECLS
+#define HAVE_POSIX_DECLS 1
+#endif
+
+#ifndef HAVE_STDBOOL_H
+#define HAVE_STDBOOL_H (199901 <= __STDC_VERSION__)
+#endif
+
+#ifndef HAVE_STRDUP
+#define HAVE_STRDUP 1
+#endif
+
+#ifndef HAVE_STRTOLL
+#define HAVE_STRTOLL 1
+#endif
+
+#ifndef HAVE_SYMLINK
+#define HAVE_SYMLINK 1
+#endif /* !defined HAVE_SYMLINK */
+
+#ifndef HAVE_SYS_STAT_H
+#define HAVE_SYS_STAT_H 1
+#endif /* !defined HAVE_SYS_STAT_H */
+
+#ifndef HAVE_SYS_WAIT_H
+#define HAVE_SYS_WAIT_H 1
+#endif /* !defined HAVE_SYS_WAIT_H */
+
+#ifndef HAVE_UNISTD_H
+#define HAVE_UNISTD_H 1
+#endif /* !defined HAVE_UNISTD_H */
+
+#ifndef HAVE_UTMPX_H
+#define HAVE_UTMPX_H 1
+#endif /* !defined HAVE_UTMPX_H */
+
+#ifndef NETBSD_INSPIRED
+# define NETBSD_INSPIRED 1
+#endif
+
+#if HAVE_INCOMPATIBLE_CTIME_R
+#define asctime_r _incompatible_asctime_r
+#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
+
+/* To avoid having 'stat' fail unnecessarily with errno == EOVERFLOW,
+ enable large files on GNUish systems ... */
+#ifndef _FILE_OFFSET_BITS
+# define _FILE_OFFSET_BITS 64
+#endif
+/* ... and on AIX ... */
+#define _LARGE_FILES 1
+/* ... and enable large inode numbers on Mac OS X 10.5 and later. */
+#define _DARWIN_USE_64_BIT_INODE 1
+
+/*
+** Nested includes
+*/
+
+/* Avoid clashes with NetBSD by renaming NetBSD's declarations. */
+#define localtime_rz sys_localtime_rz
+#define mktime_z sys_mktime_z
+#define posix2time_z sys_posix2time_z
+#define time2posix_z sys_time2posix_z
+#define timezone_t sys_timezone_t
+#define tzalloc sys_tzalloc
+#define tzfree sys_tzfree
+#include <time.h>
+#undef localtime_rz
+#undef mktime_z
+#undef posix2time_z
+#undef time2posix_z
+#undef timezone_t
+#undef tzalloc
+#undef tzfree
+
+#include <sys/types.h> /* for time_t */
+#include <string.h>
+#include <limits.h> /* for CHAR_BIT et al. */
+#include <stdlib.h>
+
+#include <errno.h>
+
+#ifndef ENAMETOOLONG
+# define ENAMETOOLONG EINVAL
+#endif
+#ifndef ENOTSUP
+# define ENOTSUP EINVAL
+#endif
+#ifndef EOVERFLOW
+# define EOVERFLOW EINVAL
+#endif
+
+#if HAVE_GETTEXT
+#include <libintl.h>
+#endif /* HAVE_GETTEXT */
+
+#if HAVE_UNISTD_H
+#include <unistd.h> /* for R_OK, and other POSIX goodness */
+#endif /* HAVE_UNISTD_H */
+
+#ifndef HAVE_STRFTIME_L
+# if _POSIX_VERSION < 200809
+# define HAVE_STRFTIME_L 0
+# else
+# define HAVE_STRFTIME_L 1
+# endif
+#endif
+
+#ifndef USG_COMPAT
+# ifndef _XOPEN_VERSION
+# define USG_COMPAT 0
+# else
+# define USG_COMPAT 1
+# endif
+#endif
+
+#ifndef HAVE_TZNAME
+# if _POSIX_VERSION < 198808 && !USG_COMPAT
+# define HAVE_TZNAME 0
+# else
+# define HAVE_TZNAME 1
+# endif
+#endif
+
+#ifndef R_OK
+#define R_OK 4
+#endif /* !defined R_OK */
+
+/* Unlike <ctype.h>'s isdigit, this also works if c < 0 | c > UCHAR_MAX. */
+#define is_digit(c) ((unsigned)(c) - '0' <= 9)
+
+/*
+** Define HAVE_STDINT_H's default value here, rather than at the
+** start, since __GLIBC__ and INTMAX_MAX's values depend on
+** previously-included files. glibc 2.1 and Solaris 10 and later have
+** stdint.h, even with pre-C99 compilers.
+*/
+#ifndef HAVE_STDINT_H
+#define HAVE_STDINT_H \
+ (199901 <= __STDC_VERSION__ \
+ || 2 < __GLIBC__ + (1 <= __GLIBC_MINOR__) \
+ || __CYGWIN__ || INTMAX_MAX)
+#endif /* !defined HAVE_STDINT_H */
+
+#if HAVE_STDINT_H
+#include <stdint.h>
+#endif /* !HAVE_STDINT_H */
+
+#ifndef HAVE_INTTYPES_H
+# define HAVE_INTTYPES_H HAVE_STDINT_H
+#endif
+#if HAVE_INTTYPES_H
+# include <inttypes.h>
+#endif
+
+/* Pre-C99 GCC compilers define __LONG_LONG_MAX__ instead of LLONG_MAX. */
+#ifdef __LONG_LONG_MAX__
+# ifndef LLONG_MAX
+# define LLONG_MAX __LONG_LONG_MAX__
+# endif
+# ifndef LLONG_MIN
+# define LLONG_MIN (-1 - LLONG_MAX)
+# endif
+#endif
+
+#ifndef INT_FAST64_MAX
+# ifdef LLONG_MAX
+typedef long long int_fast64_t;
+# define INT_FAST64_MIN LLONG_MIN
+# define INT_FAST64_MAX LLONG_MAX
+# else
+# if LONG_MAX >> 31 < 0xffffffff
+Please use a compiler that supports a 64-bit integer type (or wider);
+you may need to compile with "-DHAVE_STDINT_H".
+# endif
+typedef long int_fast64_t;
+# define INT_FAST64_MIN LONG_MIN
+# define INT_FAST64_MAX LONG_MAX
+# endif
+#endif
+
+#ifndef PRIdFAST64
+# if INT_FAST64_MAX == LLONG_MAX
+# define PRIdFAST64 "lld"
+# else
+# define PRIdFAST64 "ld"
+# endif
+#endif
+
+#ifndef SCNdFAST64
+# define SCNdFAST64 PRIdFAST64
+#endif
+
+#ifndef INT_FAST32_MAX
+# if INT_MAX >> 31 == 0
+typedef long int_fast32_t;
+# define INT_FAST32_MAX LONG_MAX
+# define INT_FAST32_MIN LONG_MIN
+# else
+typedef int int_fast32_t;
+# define INT_FAST32_MAX INT_MAX
+# define INT_FAST32_MIN INT_MIN
+# endif
+#endif
+
+#ifndef INTMAX_MAX
+# ifdef LLONG_MAX
+typedef long long intmax_t;
+# if HAVE_STRTOLL
+# define strtoimax strtoll
+# endif
+# define INTMAX_MAX LLONG_MAX
+# define INTMAX_MIN LLONG_MIN
+# else
+typedef long intmax_t;
+# define INTMAX_MAX LONG_MAX
+# define INTMAX_MIN LONG_MIN
+# endif
+# ifndef strtoimax
+# define strtoimax strtol
+# endif
+#endif
+
+#ifndef PRIdMAX
+# if INTMAX_MAX == LLONG_MAX
+# define PRIdMAX "lld"
+# else
+# define PRIdMAX "ld"
+# endif
+#endif
+
+#ifndef UINT_FAST64_MAX
+# if defined ULLONG_MAX || defined __LONG_LONG_MAX__
+typedef unsigned long long uint_fast64_t;
+# else
+# if ULONG_MAX >> 31 >> 1 < 0xffffffff
+Please use a compiler that supports a 64-bit integer type (or wider);
+you may need to compile with "-DHAVE_STDINT_H".
+# endif
+typedef unsigned long uint_fast64_t;
+# endif
+#endif
+
+#ifndef UINTMAX_MAX
+# if defined ULLONG_MAX || defined __LONG_LONG_MAX__
+typedef unsigned long long uintmax_t;
+# else
+typedef unsigned long uintmax_t;
+# endif
+#endif
+
+#ifndef PRIuMAX
+# if defined ULLONG_MAX || defined __LONG_LONG_MAX__
+# define PRIuMAX "llu"
+# else
+# define PRIuMAX "lu"
+# endif
+#endif
+
+#ifndef INT32_MAX
+#define INT32_MAX 0x7fffffff
+#endif /* !defined INT32_MAX */
+#ifndef INT32_MIN
+#define INT32_MIN (-1 - INT32_MAX)
+#endif /* !defined INT32_MIN */
+
+#ifndef SIZE_MAX
+#define SIZE_MAX ((size_t) -1)
+#endif
+
+#if 3 <= __GNUC__
+# define ATTRIBUTE_CONST __attribute__ ((const))
+# define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
+# define ATTRIBUTE_PURE __attribute__ ((__pure__))
+# define ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+#else
+# define ATTRIBUTE_CONST /* empty */
+# define ATTRIBUTE_MALLOC /* empty */
+# define ATTRIBUTE_PURE /* empty */
+# define ATTRIBUTE_FORMAT(spec) /* empty */
+#endif
+
+#if !defined _Noreturn && __STDC_VERSION__ < 201112
+# if 2 < __GNUC__ + (8 <= __GNUC_MINOR__)
+# define _Noreturn __attribute__ ((__noreturn__))
+# else
+# define _Noreturn
+# endif
+#endif
+
+#if __STDC_VERSION__ < 199901 && !defined restrict
+# define restrict /* empty */
+#endif
+
+/*
+** Workarounds for compilers/systems.
+*/
+
+#ifndef EPOCH_LOCAL
+# define EPOCH_LOCAL 0
+#endif
+#ifndef EPOCH_OFFSET
+# define EPOCH_OFFSET 0
+#endif
+#ifndef RESERVE_STD_EXT_IDS
+# define RESERVE_STD_EXT_IDS 0
+#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'. */
+#if !defined time_tz && RESERVE_STD_EXT_IDS && USE_LTZ
+# define time_tz time_t
+#endif
+
+/*
+** Compile with -Dtime_tz=T to build the tz package with a private
+** time_t type equivalent to T rather than the system-supplied time_t.
+** This debugging feature can test unusual design decisions
+** (e.g., time_t wider than 'long', or unsigned time_t) even on
+** typical platforms.
+*/
+#if defined time_tz || EPOCH_LOCAL || EPOCH_OFFSET != 0
+# define TZ_TIME_T 1
+#else
+# define TZ_TIME_T 0
+#endif
+
+#if TZ_TIME_T
+# ifdef LOCALTIME_IMPLEMENTATION
+static time_t sys_time(time_t *x) { return time(x); }
+# endif
+
+typedef time_tz tz_time_t;
+
+# undef ctime
+# define ctime tz_ctime
+# undef ctime_r
+# define ctime_r tz_ctime_r
+# undef difftime
+# define difftime tz_difftime
+# undef gmtime
+# define gmtime tz_gmtime
+# undef gmtime_r
+# define gmtime_r tz_gmtime_r
+# undef localtime
+# define localtime tz_localtime
+# undef localtime_r
+# define localtime_r tz_localtime_r
+# undef localtime_rz
+# define localtime_rz tz_localtime_rz
+# undef mktime
+# define mktime tz_mktime
+# undef mktime_z
+# define mktime_z tz_mktime_z
+# undef offtime
+# define offtime tz_offtime
+# undef posix2time
+# define posix2time tz_posix2time
+# undef posix2time_z
+# define posix2time_z tz_posix2time_z
+# undef strftime
+# define strftime tz_strftime
+# undef time
+# define time tz_time
+# undef time2posix
+# define time2posix tz_time2posix
+# undef time2posix_z
+# define time2posix_z tz_time2posix_z
+# undef time_t
+# define time_t tz_time_t
+# undef timegm
+# define timegm tz_timegm
+# undef timelocal
+# define timelocal tz_timelocal
+# undef timeoff
+# define timeoff tz_timeoff
+# undef tzalloc
+# define tzalloc tz_tzalloc
+# undef tzfree
+# define tzfree tz_tzfree
+# undef tzset
+# define tzset tz_tzset
+# undef tzsetwall
+# define tzsetwall tz_tzsetwall
+# if HAVE_STRFTIME_L
+# undef strftime_l
+# define strftime_l tz_strftime_l
+# endif
+# if HAVE_TZNAME
+# undef tzname
+# define tzname tz_tzname
+# endif
+# if USG_COMPAT
+# undef daylight
+# define daylight tz_daylight
+# undef timezone
+# define timezone tz_timezone
+# endif
+# ifdef ALTZONE
+# undef altzone
+# define altzone tz_altzone
+# endif
+
+char *ctime(time_t const *);
+char *ctime_r(time_t const *, char *);
+double difftime(time_t, time_t) ATTRIBUTE_CONST;
+size_t strftime(char *restrict, size_t, char const *restrict,
+ struct tm const *restrict);
+# if HAVE_STRFTIME_L
+size_t strftime_l(char *restrict, size_t, char const *restrict,
+ struct tm const *restrict, locale_t);
+# endif
+struct tm *gmtime(time_t const *);
+struct tm *gmtime_r(time_t const *restrict, struct tm *restrict);
+struct tm *localtime(time_t const *);
+struct tm *localtime_r(time_t const *restrict, struct tm *restrict);
+time_t mktime(struct tm *);
+time_t time(time_t *);
+void tzset(void);
+#endif
+
+#if !HAVE_DECL_ASCTIME_R && !defined asctime_r
+extern char *asctime_r(struct tm const *restrict, char *restrict);
+#endif
+
+#ifndef HAVE_DECL_ENVIRON
+# if defined environ || defined __USE_GNU
+# define HAVE_DECL_ENVIRON 1
+# else
+# define HAVE_DECL_ENVIRON 0
+# endif
+#endif
+
+#if !HAVE_DECL_ENVIRON
+extern char **environ;
+#endif
+
+#if TZ_TIME_T || !HAVE_POSIX_DECLS
+# if HAVE_TZNAME
+extern char *tzname[];
+# endif
+# if USG_COMPAT
+extern long timezone;
+extern int daylight;
+# endif
+#endif
+
+#ifdef ALTZONE
+extern long altzone;
+#endif
+
+/*
+** The STD_INSPIRED functions are similar, but most also need
+** declarations if time_tz is defined.
+*/
+
+#ifdef STD_INSPIRED
+# if TZ_TIME_T || !defined tzsetwall
+void tzsetwall(void);
+# endif
+# if TZ_TIME_T || !defined offtime
+struct tm *offtime(time_t const *, long);
+# endif
+# if TZ_TIME_T || !defined timegm
+time_t timegm(struct tm *);
+# endif
+# if TZ_TIME_T || !defined timelocal
+time_t timelocal(struct tm *);
+# endif
+# if TZ_TIME_T || !defined timeoff
+time_t timeoff(struct tm *, long);
+# endif
+# if TZ_TIME_T || !defined time2posix
+time_t time2posix(time_t);
+# endif
+# if TZ_TIME_T || !defined posix2time
+time_t posix2time(time_t);
+# endif
+#endif
+
+/* Infer TM_ZONE on systems where this information is known, but suppress
+ guessing if NO_TM_ZONE is defined. Similarly for TM_GMTOFF. */
+#if (defined __GLIBC__ \
+ || defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__ \
+ || (defined __APPLE__ && defined __MACH__))
+# if !defined TM_GMTOFF && !defined NO_TM_GMTOFF
+# define TM_GMTOFF tm_gmtoff
+# endif
+# if !defined TM_ZONE && !defined NO_TM_ZONE
+# define TM_ZONE tm_zone
+# endif
+#endif
+
+/*
+** Define functions that are ABI compatible with NetBSD but have
+** better prototypes. NetBSD 6.1.4 defines a pointer type timezone_t
+** and labors under the misconception that 'const timezone_t' is a
+** pointer to a constant. This use of 'const' is ineffective, so it
+** is not done here. What we call 'struct state' NetBSD calls
+** 'struct __state', but this is a private name so it doesn't matter.
+*/
+#if NETBSD_INSPIRED
+typedef struct state *timezone_t;
+struct tm *localtime_rz(timezone_t restrict, time_t const *restrict,
+ struct tm *restrict);
+time_t mktime_z(timezone_t restrict, struct tm *restrict);
+timezone_t tzalloc(char const *);
+void tzfree(timezone_t);
+# ifdef STD_INSPIRED
+# if TZ_TIME_T || !defined posix2time_z
+time_t posix2time_z(timezone_t, time_t) ATTRIBUTE_PURE;
+# endif
+# if TZ_TIME_T || !defined time2posix_z
+time_t time2posix_z(timezone_t, time_t) ATTRIBUTE_PURE;
+# endif
+# endif
+#endif
+
+/*
+** Finally, some convenience items.
+*/
+
+#if HAVE_STDBOOL_H
+# include <stdbool.h>
+#else
+# define true 1
+# define false 0
+# define bool int
+#endif
+
+#define TYPE_BIT(type) (sizeof (type) * CHAR_BIT)
+#define TYPE_SIGNED(type) (((type) -1) < 0)
+#define TWOS_COMPLEMENT(t) ((t) ~ (t) 0 < 0)
+
+/* Max and min values of the integer type T, of which only the bottom
+ B bits are used, and where the highest-order used bit is considered
+ to be a sign bit if T is signed. */
+#define MAXVAL(t, b) \
+ ((t) (((t) 1 << ((b) - 1 - TYPE_SIGNED(t))) \
+ - 1 + ((t) 1 << ((b) - 1 - TYPE_SIGNED(t)))))
+#define MINVAL(t, b) \
+ ((t) (TYPE_SIGNED(t) ? - TWOS_COMPLEMENT(t) - MAXVAL(t, b) : 0))
+
+/* The extreme time values, assuming no padding. */
+#define TIME_T_MIN_NO_PADDING MINVAL(time_t, TYPE_BIT(time_t))
+#define TIME_T_MAX_NO_PADDING MAXVAL(time_t, TYPE_BIT(time_t))
+
+/* The extreme time values. These are macros, not constants, so that
+ any portability problem occur only when compiling .c files that use
+ the macros, which is safer for applications that need only zdump and zic.
+ This implementation assumes no padding if time_t is signed and
+ either the compiler lacks support for _Generic or time_t is not one
+ of the standard signed integer types. */
+#if HAVE_GENERIC
+# define TIME_T_MIN \
+ _Generic((time_t) 0, \
+ signed char: SCHAR_MIN, short: SHRT_MIN, \
+ int: INT_MIN, long: LONG_MIN, long long: LLONG_MIN, \
+ default: TIME_T_MIN_NO_PADDING)
+# define TIME_T_MAX \
+ (TYPE_SIGNED(time_t) \
+ ? _Generic((time_t) 0, \
+ signed char: SCHAR_MAX, short: SHRT_MAX, \
+ int: INT_MAX, long: LONG_MAX, long long: LLONG_MAX, \
+ default: TIME_T_MAX_NO_PADDING) \
+ : (time_t) -1)
+#else
+# define TIME_T_MIN TIME_T_MIN_NO_PADDING
+# define TIME_T_MAX TIME_T_MAX_NO_PADDING
+#endif
+
+/*
+** 302 / 1000 is log10(2.0) rounded up.
+** Subtract one for the sign bit if the type is signed;
+** add one for integer division truncation;
+** add one more for a minus sign if the type is signed.
+*/
+#define INT_STRLEN_MAXIMUM(type) \
+ ((TYPE_BIT(type) - TYPE_SIGNED(type)) * 302 / 1000 + \
+ 1 + TYPE_SIGNED(type))
+
+/*
+** INITIALIZE(x)
+*/
+
+#ifdef GCC_LINT
+# define INITIALIZE(x) ((x) = 0)
+#else
+# define INITIALIZE(x)
+#endif
+
+#ifndef UNINIT_TRAP
+# define UNINIT_TRAP 0
+#endif
+
+/*
+** For the benefit of GNU folk...
+** '_(MSGID)' uses the current locale's message library string for MSGID.
+** The default is to use gettext if available, and use MSGID otherwise.
+*/
+
+#if HAVE_GETTEXT
+#define _(msgid) gettext(msgid)
+#else /* !HAVE_GETTEXT */
+#define _(msgid) msgid
+#endif /* !HAVE_GETTEXT */
+
+#if !defined TZ_DOMAIN && defined HAVE_GETTEXT
+# define TZ_DOMAIN "tz"
+#endif
+
+#if HAVE_INCOMPATIBLE_CTIME_R
+#undef asctime_r
+#undef ctime_r
+char *asctime_r(struct tm const *, char *);
+char *ctime_r(time_t const *, char *);
+#endif /* HAVE_INCOMPATIBLE_CTIME_R */
+
+/* Handy macros that are independent of tzfile implementation. */
+
+#define YEARSPERREPEAT 400 /* years before a Gregorian repeat */
+
+#define SECSPERMIN 60
+#define MINSPERHOUR 60
+#define HOURSPERDAY 24
+#define DAYSPERWEEK 7
+#define DAYSPERNYEAR 365
+#define DAYSPERLYEAR 366
+#define SECSPERHOUR (SECSPERMIN * MINSPERHOUR)
+#define SECSPERDAY ((int_fast32_t) SECSPERHOUR * HOURSPERDAY)
+#define MONSPERYEAR 12
+
+#define TM_SUNDAY 0
+#define TM_MONDAY 1
+#define TM_TUESDAY 2
+#define TM_WEDNESDAY 3
+#define TM_THURSDAY 4
+#define TM_FRIDAY 5
+#define TM_SATURDAY 6
+
+#define TM_JANUARY 0
+#define TM_FEBRUARY 1
+#define TM_MARCH 2
+#define TM_APRIL 3
+#define TM_MAY 4
+#define TM_JUNE 5
+#define TM_JULY 6
+#define TM_AUGUST 7
+#define TM_SEPTEMBER 8
+#define TM_OCTOBER 9
+#define TM_NOVEMBER 10
+#define TM_DECEMBER 11
+
+#define TM_YEAR_BASE 1900
+
+#define EPOCH_YEAR 1970
+#define EPOCH_WDAY TM_THURSDAY
+
+#define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
+
+/*
+** Since everything in isleap is modulo 400 (or a factor of 400), we know that
+** isleap(y) == isleap(y % 400)
+** and so
+** isleap(a + b) == isleap((a + b) % 400)
+** or
+** isleap(a + b) == isleap(a % 400 + b % 400)
+** This is true even if % means modulo rather than Fortran remainder
+** (which is allowed by C89 but not by C99 or later).
+** We use this to avoid addition overflow problems.
+*/
+
+#define isleap_sum(a, b) isleap((a) % 400 + (b) % 400)
+
+
+/*
+** The Gregorian year averages 365.2425 days, which is 31556952 seconds.
+*/
+
+#define AVGSECSPERYEAR 31556952L
+#define SECSPERREPEAT \
+ ((int_fast64_t) YEARSPERREPEAT * (int_fast64_t) AVGSECSPERYEAR)
+#define SECSPERREPEAT_BITS 34 /* ceil(log2(SECSPERREPEAT)) */
+
+#endif /* !defined PRIVATE_H */
diff --git a/strftime.c b/strftime.c
new file mode 100644
index 000000000000..e85589079172
--- /dev/null
+++ b/strftime.c
@@ -0,0 +1,633 @@
+/* Convert a broken-down timestamp to a string. */
+
+/* Copyright 1989 The Regents of the University of California.
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+ 1. Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+ 3. Neither the name of the University nor the names of its contributors
+ may be used to endorse or promote products derived from this software
+ without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
+ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ SUCH DAMAGE. */
+
+/*
+** Based on the UCB version with the copyright notice appearing above.
+**
+** This is ANSIish only when "multibyte character == plain character".
+*/
+
+#include "private.h"
+
+#include <fcntl.h>
+#include <locale.h>
+#include <stdio.h>
+
+#ifndef DEPRECATE_TWO_DIGIT_YEARS
+# define DEPRECATE_TWO_DIGIT_YEARS false
+#endif
+
+struct lc_time_T {
+ const char * mon[MONSPERYEAR];
+ const char * month[MONSPERYEAR];
+ const char * wday[DAYSPERWEEK];
+ const char * weekday[DAYSPERWEEK];
+ const char * X_fmt;
+ const char * x_fmt;
+ const char * c_fmt;
+ const char * am;
+ const char * pm;
+ const char * date_fmt;
+};
+
+#define Locale (&C_time_locale)
+
+static const struct lc_time_T C_time_locale = {
+ {
+ "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+ "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
+ }, {
+ "January", "February", "March", "April", "May", "June",
+ "July", "August", "September", "October", "November", "December"
+ }, {
+ "Sun", "Mon", "Tue", "Wed",
+ "Thu", "Fri", "Sat"
+ }, {
+ "Sunday", "Monday", "Tuesday", "Wednesday",
+ "Thursday", "Friday", "Saturday"
+ },
+
+ /* X_fmt */
+ "%H:%M:%S",
+
+ /*
+ ** x_fmt
+ ** C99 and later require this format.
+ ** Using just numbers (as here) makes Quakers happier;
+ ** it's also compatible with SVR4.
+ */
+ "%m/%d/%y",
+
+ /*
+ ** c_fmt
+ ** C99 and later require this format.
+ ** Previously this code used "%D %X", but we now conform to C99.
+ ** Note that
+ ** "%a %b %d %H:%M:%S %Y"
+ ** is used by Solaris 2.3.
+ */
+ "%a %b %e %T %Y",
+
+ /* am */
+ "AM",
+
+ /* pm */
+ "PM",
+
+ /* date_fmt */
+ "%a %b %e %H:%M:%S %Z %Y"
+};
+
+enum warn { IN_NONE, IN_SOME, IN_THIS, IN_ALL };
+
+static char * _add(const char *, char *, const char *);
+static char * _conv(int, const char *, char *, const char *);
+static char * _fmt(const char *, const struct tm *, char *, const char *,
+ enum warn *);
+static char * _yconv(int, int, bool, bool, char *, char const *);
+
+#ifndef YEAR_2000_NAME
+#define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
+#endif /* !defined YEAR_2000_NAME */
+
+#if HAVE_STRFTIME_L
+size_t
+strftime_l(char *s, size_t maxsize, char const *format, struct tm const *t,
+ locale_t locale)
+{
+ /* Just call strftime, as only the C locale is supported. */
+ return strftime(s, maxsize, format, t);
+}
+#endif
+
+size_t
+strftime(char *s, size_t maxsize, const char *format, const struct tm *t)
+{
+ char * p;
+ enum warn warn = IN_NONE;
+
+ tzset();
+ p = _fmt(format, t, s, s + maxsize, &warn);
+ if (DEPRECATE_TWO_DIGIT_YEARS
+ && warn != IN_NONE && getenv(YEAR_2000_NAME)) {
+ fprintf(stderr, "\n");
+ fprintf(stderr, "strftime format \"%s\" ", format);
+ fprintf(stderr, "yields only two digits of years in ");
+ if (warn == IN_SOME)
+ fprintf(stderr, "some locales");
+ else if (warn == IN_THIS)
+ fprintf(stderr, "the current locale");
+ else fprintf(stderr, "all locales");
+ fprintf(stderr, "\n");
+ }
+ if (p == s + maxsize)
+ return 0;
+ *p = '\0';
+ return p - s;
+}
+
+static char *
+_fmt(const char *format, const struct tm *t, char *pt,
+ const char *ptlim, enum warn *warnp)
+{
+ for ( ; *format; ++format) {
+ if (*format == '%') {
+label:
+ switch (*++format) {
+ case '\0':
+ --format;
+ break;
+ case 'A':
+ pt = _add((t->tm_wday < 0 ||
+ t->tm_wday >= DAYSPERWEEK) ?
+ "?" : Locale->weekday[t->tm_wday],
+ pt, ptlim);
+ continue;
+ case 'a':
+ pt = _add((t->tm_wday < 0 ||
+ t->tm_wday >= DAYSPERWEEK) ?
+ "?" : Locale->wday[t->tm_wday],
+ pt, ptlim);
+ continue;
+ case 'B':
+ pt = _add((t->tm_mon < 0 ||
+ t->tm_mon >= MONSPERYEAR) ?
+ "?" : Locale->month[t->tm_mon],
+ pt, ptlim);
+ continue;
+ case 'b':
+ case 'h':
+ pt = _add((t->tm_mon < 0 ||
+ t->tm_mon >= MONSPERYEAR) ?
+ "?" : Locale->mon[t->tm_mon],
+ pt, ptlim);
+ continue;
+ case 'C':
+ /*
+ ** %C used to do a...
+ ** _fmt("%a %b %e %X %Y", t);
+ ** ...whereas now POSIX 1003.2 calls for
+ ** something completely different.
+ ** (ado, 1993-05-24)
+ */
+ pt = _yconv(t->tm_year, TM_YEAR_BASE,
+ true, false, pt, ptlim);
+ continue;
+ case 'c':
+ {
+ enum warn warn2 = IN_SOME;
+
+ pt = _fmt(Locale->c_fmt, t, pt, ptlim, &warn2);
+ if (warn2 == IN_ALL)
+ warn2 = IN_THIS;
+ if (warn2 > *warnp)
+ *warnp = warn2;
+ }
+ continue;
+ case 'D':
+ pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp);
+ continue;
+ case 'd':
+ pt = _conv(t->tm_mday, "%02d", pt, ptlim);
+ continue;
+ case 'E':
+ case 'O':
+ /*
+ ** Locale modifiers of C99 and later.
+ ** The sequences
+ ** %Ec %EC %Ex %EX %Ey %EY
+ ** %Od %oe %OH %OI %Om %OM
+ ** %OS %Ou %OU %OV %Ow %OW %Oy
+ ** are supposed to provide alternative
+ ** representations.
+ */
+ goto label;
+ case 'e':
+ pt = _conv(t->tm_mday, "%2d", pt, ptlim);
+ continue;
+ case 'F':
+ pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp);
+ continue;
+ case 'H':
+ pt = _conv(t->tm_hour, "%02d", pt, ptlim);
+ continue;
+ case 'I':
+ pt = _conv((t->tm_hour % 12) ?
+ (t->tm_hour % 12) : 12,
+ "%02d", pt, ptlim);
+ continue;
+ case 'j':
+ pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
+ continue;
+ case 'k':
+ /*
+ ** This used to be...
+ ** _conv(t->tm_hour % 12 ?
+ ** t->tm_hour % 12 : 12, 2, ' ');
+ ** ...and has been changed to the below to
+ ** match SunOS 4.1.1 and Arnold Robbins'
+ ** strftime version 3.0. That is, "%k" and
+ ** "%l" have been swapped.
+ ** (ado, 1993-05-24)
+ */
+ pt = _conv(t->tm_hour, "%2d", pt, ptlim);
+ continue;
+#ifdef KITCHEN_SINK
+ case 'K':
+ /*
+ ** After all this time, still unclaimed!
+ */
+ pt = _add("kitchen sink", pt, ptlim);
+ continue;
+#endif /* defined KITCHEN_SINK */
+ case 'l':
+ /*
+ ** This used to be...
+ ** _conv(t->tm_hour, 2, ' ');
+ ** ...and has been changed to the below to
+ ** match SunOS 4.1.1 and Arnold Robbin's
+ ** strftime version 3.0. That is, "%k" and
+ ** "%l" have been swapped.
+ ** (ado, 1993-05-24)
+ */
+ pt = _conv((t->tm_hour % 12) ?
+ (t->tm_hour % 12) : 12,
+ "%2d", pt, ptlim);
+ continue;
+ case 'M':
+ pt = _conv(t->tm_min, "%02d", pt, ptlim);
+ continue;
+ case 'm':
+ pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
+ continue;
+ case 'n':
+ pt = _add("\n", pt, ptlim);
+ continue;
+ case 'p':
+ pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
+ Locale->pm :
+ Locale->am,
+ pt, ptlim);
+ continue;
+ case 'R':
+ pt = _fmt("%H:%M", t, pt, ptlim, warnp);
+ continue;
+ case 'r':
+ pt = _fmt("%I:%M:%S %p", t, pt, ptlim, warnp);
+ continue;
+ case 'S':
+ pt = _conv(t->tm_sec, "%02d", pt, ptlim);
+ continue;
+ case 's':
+ {
+ struct tm tm;
+ char buf[INT_STRLEN_MAXIMUM(
+ time_t) + 1];
+ time_t mkt;
+
+ tm = *t;
+ mkt = mktime(&tm);
+ if (TYPE_SIGNED(time_t))
+ sprintf(buf, "%"PRIdMAX,
+ (intmax_t) mkt);
+ else sprintf(buf, "%"PRIuMAX,
+ (uintmax_t) mkt);
+ pt = _add(buf, pt, ptlim);
+ }
+ continue;
+ case 'T':
+ pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp);
+ continue;
+ case 't':
+ pt = _add("\t", pt, ptlim);
+ continue;
+ case 'U':
+ pt = _conv((t->tm_yday + DAYSPERWEEK -
+ t->tm_wday) / DAYSPERWEEK,
+ "%02d", pt, ptlim);
+ continue;
+ case 'u':
+ /*
+ ** From Arnold Robbins' strftime version 3.0:
+ ** "ISO 8601: Weekday as a decimal number
+ ** [1 (Monday) - 7]"
+ ** (ado, 1993-05-24)
+ */
+ pt = _conv((t->tm_wday == 0) ?
+ DAYSPERWEEK : t->tm_wday,
+ "%d", pt, ptlim);
+ continue;
+ case 'V': /* ISO 8601 week number */
+ case 'G': /* ISO 8601 year (four digits) */
+ case 'g': /* ISO 8601 year (two digits) */
+/*
+** From Arnold Robbins' strftime version 3.0: "the week number of the
+** year (the first Monday as the first day of week 1) as a decimal number
+** (01-53)."
+** (ado, 1993-05-24)
+**
+** From <https://www.cl.cam.ac.uk/~mgk25/iso-time.html> by Markus Kuhn:
+** "Week 01 of a year is per definition the first week which has the
+** Thursday in this year, which is equivalent to the week which contains
+** the fourth day of January. In other words, the first week of a new year
+** is the week which has the majority of its days in the new year. Week 01
+** might also contain days from the previous year and the week before week
+** 01 of a year is the last week (52 or 53) of the previous year even if
+** it contains days from the new year. A week starts with Monday (day 1)
+** and ends with Sunday (day 7). For example, the first week of the year
+** 1997 lasts from 1996-12-30 to 1997-01-05..."
+** (ado, 1996-01-02)
+*/
+ {
+ int year;
+ int base;
+ int yday;
+ int wday;
+ int w;
+
+ year = t->tm_year;
+ base = TM_YEAR_BASE;
+ yday = t->tm_yday;
+ wday = t->tm_wday;
+ for ( ; ; ) {
+ int len;
+ int bot;
+ int top;
+
+ len = isleap_sum(year, base) ?
+ DAYSPERLYEAR :
+ DAYSPERNYEAR;
+ /*
+ ** What yday (-3 ... 3) does
+ ** the ISO year begin on?
+ */
+ bot = ((yday + 11 - wday) %
+ DAYSPERWEEK) - 3;
+ /*
+ ** What yday does the NEXT
+ ** ISO year begin on?
+ */
+ top = bot -
+ (len % DAYSPERWEEK);
+ if (top < -3)
+ top += DAYSPERWEEK;
+ top += len;
+ if (yday >= top) {
+ ++base;
+ w = 1;
+ break;
+ }
+ if (yday >= bot) {
+ w = 1 + ((yday - bot) /
+ DAYSPERWEEK);
+ break;
+ }
+ --base;
+ yday += isleap_sum(year, base) ?
+ DAYSPERLYEAR :
+ DAYSPERNYEAR;
+ }
+#ifdef XPG4_1994_04_09
+ if ((w == 52 &&
+ t->tm_mon == TM_JANUARY) ||
+ (w == 1 &&
+ t->tm_mon == TM_DECEMBER))
+ w = 53;
+#endif /* defined XPG4_1994_04_09 */
+ if (*format == 'V')
+ pt = _conv(w, "%02d",
+ pt, ptlim);
+ else if (*format == 'g') {
+ *warnp = IN_ALL;
+ pt = _yconv(year, base,
+ false, true,
+ pt, ptlim);
+ } else pt = _yconv(year, base,
+ true, true,
+ pt, ptlim);
+ }
+ continue;
+ case 'v':
+ /*
+ ** From Arnold Robbins' strftime version 3.0:
+ ** "date as dd-bbb-YYYY"
+ ** (ado, 1993-05-24)
+ */
+ pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp);
+ continue;
+ case 'W':
+ pt = _conv((t->tm_yday + DAYSPERWEEK -
+ (t->tm_wday ?
+ (t->tm_wday - 1) :
+ (DAYSPERWEEK - 1))) / DAYSPERWEEK,
+ "%02d", pt, ptlim);
+ continue;
+ case 'w':
+ pt = _conv(t->tm_wday, "%d", pt, ptlim);
+ continue;
+ case 'X':
+ pt = _fmt(Locale->X_fmt, t, pt, ptlim, warnp);
+ continue;
+ case 'x':
+ {
+ enum warn warn2 = IN_SOME;
+
+ pt = _fmt(Locale->x_fmt, t, pt, ptlim, &warn2);
+ if (warn2 == IN_ALL)
+ warn2 = IN_THIS;
+ if (warn2 > *warnp)
+ *warnp = warn2;
+ }
+ continue;
+ case 'y':
+ *warnp = IN_ALL;
+ pt = _yconv(t->tm_year, TM_YEAR_BASE,
+ false, true,
+ pt, ptlim);
+ continue;
+ case 'Y':
+ pt = _yconv(t->tm_year, TM_YEAR_BASE,
+ true, true,
+ pt, ptlim);
+ continue;
+ case 'Z':
+#ifdef TM_ZONE
+ pt = _add(t->TM_ZONE, pt, ptlim);
+#elif HAVE_TZNAME
+ if (t->tm_isdst >= 0)
+ pt = _add(tzname[t->tm_isdst != 0],
+ pt, ptlim);
+#endif
+ /*
+ ** C99 and later say that %Z must be
+ ** replaced by the empty string if the
+ ** time zone is not determinable.
+ */
+ continue;
+ case 'z':
+#if defined TM_GMTOFF || USG_COMPAT || defined ALTZONE
+ {
+ long diff;
+ char const * sign;
+ bool negative;
+
+# ifdef TM_GMTOFF
+ diff = t->TM_GMTOFF;
+# else
+ /*
+ ** C99 and later say that the UT offset must
+ ** be computed by looking only at
+ ** tm_isdst. This requirement is
+ ** incorrect, since it means the code
+ ** must rely on magic (in this case
+ ** altzone and timezone), and the
+ ** magic might not have the correct
+ ** offset. Doing things correctly is
+ ** tricky and requires disobeying the standard;
+ ** see GNU C strftime for details.
+ ** For now, punt and conform to the
+ ** standard, even though it's incorrect.
+ **
+ ** C99 and later say that %z must be replaced by
+ ** the empty string if the time zone is not
+ ** determinable, so output nothing if the
+ ** appropriate variables are not available.
+ */
+ if (t->tm_isdst < 0)
+ continue;
+ if (t->tm_isdst == 0)
+# if USG_COMPAT
+ diff = -timezone;
+# else
+ continue;
+# endif
+ else
+# ifdef ALTZONE
+ diff = -altzone;
+# else
+ continue;
+# endif
+# endif
+ negative = diff < 0;
+ if (diff == 0) {
+#ifdef TM_ZONE
+ negative = t->TM_ZONE[0] == '-';
+#else
+ negative = t->tm_isdst < 0;
+# if HAVE_TZNAME
+ if (tzname[t->tm_isdst != 0][0] == '-')
+ negative = true;
+# endif
+#endif
+ }
+ if (negative) {
+ sign = "-";
+ diff = -diff;
+ } else sign = "+";
+ pt = _add(sign, pt, ptlim);
+ diff /= SECSPERMIN;
+ diff = (diff / MINSPERHOUR) * 100 +
+ (diff % MINSPERHOUR);
+ pt = _conv(diff, "%04d", pt, ptlim);
+ }
+#endif
+ continue;
+ case '+':
+ pt = _fmt(Locale->date_fmt, t, pt, ptlim,
+ 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;
+ }
+ }
+ if (pt == ptlim)
+ break;
+ *pt++ = *format;
+ }
+ return pt;
+}
+
+static char *
+_conv(int n, const char *format, char *pt, const char *ptlim)
+{
+ char buf[INT_STRLEN_MAXIMUM(int) + 1];
+
+ sprintf(buf, format, n);
+ return _add(buf, pt, ptlim);
+}
+
+static char *
+_add(const char *str, char *pt, const char *ptlim)
+{
+ while (pt < ptlim && (*pt = *str++) != '\0')
+ ++pt;
+ return pt;
+}
+
+/*
+** POSIX and the C Standard are unclear or inconsistent about
+** what %C and %y do if the year is negative or exceeds 9999.
+** Use the convention that %C concatenated with %y yields the
+** same output as %Y, and that %Y contains at least 4 bytes,
+** with more only if necessary.
+*/
+
+static char *
+_yconv(int a, int b, bool convert_top, bool convert_yy,
+ char *pt, const char *ptlim)
+{
+ register int lead;
+ register int trail;
+
+#define DIVISOR 100
+ trail = a % DIVISOR + b % DIVISOR;
+ lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
+ trail %= DIVISOR;
+ if (trail < 0 && lead > 0) {
+ trail += DIVISOR;
+ --lead;
+ } else if (lead < 0 && trail > 0) {
+ trail -= DIVISOR;
+ ++lead;
+ }
+ if (convert_top) {
+ if (lead == 0 && trail < 0)
+ pt = _add("-0", pt, ptlim);
+ else pt = _conv(lead, "%02d", pt, ptlim);
+ }
+ if (convert_yy)
+ pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
+ return pt;
+}
diff --git a/theory.html b/theory.html
new file mode 100644
index 000000000000..fc2102b3e3c9
--- /dev/null
+++ b/theory.html
@@ -0,0 +1,1304 @@
+<html lang="en">
+<head>
+ <title>Theory and pragmatics of the tz code and data</title>
+ <meta charset="UTF-8">
+</head>
+
+<body>
+<h1>Theory and pragmatics of the <code><abbr>tz</abbr></code> code and data</h1>
+ <h3>Outline</h3>
+ <nav>
+ <ul>
+ <li><a href="#scope">Scope of the <code><abbr>tz</abbr></code>
+ database</a></li>
+ <li><a href="#naming">Names of time zone rulesets</a></li>
+ <li><a href="#abbreviations">Time zone abbreviations</a></li>
+ <li><a href="#accuracy">Accuracy of the <code><abbr>tz</abbr></code>
+ database</a></li>
+ <li><a href="#functions">Time and date functions</a></li>
+ <li><a href="#stability">Interface stability</a></li>
+ <li><a href="#calendar">Calendrical issues</a></li>
+ <li><a href="#planets">Time and time zones on other planets</a></li>
+ </ul>
+ </nav>
+
+<section>
+ <h2 id="scope">Scope of the <code><abbr>tz</abbr></code> database</h2>
+<p>
+The <a
+href="https://www.iana.org/time-zones"><code><abbr>tz</abbr></code>
+database</a> attempts to record the history and predicted future of
+all computer-based clocks that track civil time.
+It organizes <a href="tz-link.html">time zone and daylight saving time
+data</a> by partitioning the world into <a
+href="https://en.wikipedia.org/wiki/List_of_tz_database_time_zones">regions</a>
+whose clocks all agree about timestamps that occur after the <a
+href="https://en.wikipedia.org/wiki/Unix_time">POSIX Epoch</a>
+(1970-01-01 00:00:00 <a
+href="https://en.wikipedia.org/wiki/Coordinated_Universal_Time"><abbr
+title="Coordinated Universal Time">UTC</abbr></a>).
+The database labels each such region with a notable location and
+records all known clock transitions for that location.
+Although 1970 is a somewhat-arbitrary cutoff, there are significant
+challenges to moving the cutoff earlier even by a decade or two, due
+to the wide variety of local practices before computer timekeeping
+became prevalent.
+</p>
+
+<p>
+Clock transitions before 1970 are recorded for each such location,
+because most systems support timestamps before 1970 and could
+misbehave if data entries were omitted for pre-1970 transitions.
+However, the database is not designed for and does not suffice for
+applications requiring accurate handling of all past times everywhere,
+as it would take far too much effort and guesswork to record all
+details of pre-1970 civil timekeeping.
+Although some information outside the scope of the database is
+collected in a file <code>backzone</code> that is distributed along
+with the database proper, this file is less reliable and does not
+necessarily follow database guidelines.
+</p>
+
+<p>
+As described below, reference source code for using the
+<code><abbr>tz</abbr></code> database is also available.
+The <code><abbr>tz</abbr></code> code is upwards compatible with <a
+href="https://en.wikipedia.org/wiki/POSIX">POSIX</a>, an international
+standard for <a
+href="https://en.wikipedia.org/wiki/Unix">UNIX</a>-like systems.
+As of this writing, the current edition of POSIX is: <a
+href="http://pubs.opengroup.org/onlinepubs/9699919799/"> The Open
+Group Base Specifications Issue 7</a>, IEEE Std 1003.1-2017, 2018
+Edition.
+Because the database's scope encompasses real-world changes to civil
+timekeeping, its model for describing time is more complex than the
+standard and daylight saving times supported by POSIX.
+A <code><abbr>tz</abbr></code> region corresponds to a ruleset that can
+have more than two changes per year, these changes need not merely
+flip back and forth between two alternatives, and the rules themselves
+can change at times.
+Whether and when a <code><abbr>tz</abbr></code> region changes its
+clock, and even the region's notional base offset from UTC, are variable.
+It does not always make sense to talk about a region's
+"base offset", since it is not necessarily a single number.
+</p>
+
+</section>
+
+<section>
+ <h2 id="naming">Names of time zone rulesets</h2>
+<p>
+Each <code><abbr>tz</abbr></code> region has a unique name that
+corresponds to a set of time zone rules.
+Inexperienced users are not expected to select these names unaided.
+Distributors should provide documentation and/or a simple selection
+interface that explains the names; for one example, see the
+<code>tzselect</code> program in the <code><abbr>tz</abbr></code> code.
+The <a href="http://cldr.unicode.org/">Unicode Common Locale Data
+Repository</a> contains data that may be useful for other selection
+interfaces.
+</p>
+
+<p>
+The naming conventions attempt to strike a balance
+among the following goals:
+</p>
+
+<ul>
+ <li>
+ Uniquely identify every region where clocks have agreed since 1970.
+ This is essential for the intended use: static clocks keeping local
+ civil time.
+ </li>
+ <li>
+ Indicate to experts where that region is.
+ </li>
+ <li>
+ Be robust in the presence of political changes.
+ For example, names of countries are ordinarily not used, to avoid
+ incompatibilities when countries change their name (e.g.,
+ Zaire&rarr;Congo) or when locations change countries (e.g., Hong
+ Kong from UK colony to China).
+ </li>
+ <li>
+ Be portable to a wide variety of implementations.
+ </li>
+ <li>
+ Use a consistent naming conventions over the entire world.
+ </li>
+</ul>
+
+<p>
+Names normally have the form
+<var>AREA</var><code>/</code><var>LOCATION</var>, where
+<var>AREA</var> is the name of a continent or ocean, and
+<var>LOCATION</var> is the name of a specific location within that
+region.
+North and South America share the same area, '<code>America</code>'.
+Typical names are '<code>Africa/Cairo</code>',
+'<code>America/New_York</code>', and '<code>Pacific/Honolulu</code>'.
+Some names are further qualified to help avoid confusion; for example,
+'<code>America/Indiana/Petersburg</code>' distinguishes Petersburg,
+Indiana from other Petersburgs in America.
+</p>
+
+<p>
+Here are the general guidelines used for
+choosing <code><abbr>tz</abbr></code> region names,
+in decreasing order of importance:
+</p>
+
+<ul>
+ <li>
+ Use only valid POSIX file name components (i.e., the parts of
+ names other than '<code>/</code>').
+ Do not use the file name components '<code>.</code>' and
+ '<code>..</code>'.
+ Within a file name component, use only <a
+ href="https://en.wikipedia.org/wiki/ASCII">ASCII</a> letters,
+ '<code>.</code>', '<code>-</code>' and '<code>_</code>'.
+ Do not use digits, as that might create an ambiguity with <a
+ href="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03">POSIX
+ <code>TZ</code> strings</a>.
+ A file name component must not exceed 14 characters or start with
+ '<code>-</code>'.
+ E.g., prefer <code>Asia/Brunei</code> to
+ <code>Asia/Bandar_Seri_Begawan</code>.
+ Exceptions: see the discussion of legacy names below.
+ </li>
+ <li>
+ A name must not be empty, or contain '<code>//</code>', or
+ start or end with '<code>/</code>'.
+ </li>
+ <li>
+ Do not use names that differ only in case.
+ Although the reference implementation is case-sensitive, some
+ other implementations are not, and they would mishandle names
+ differing only in case.
+ </li>
+ <li>
+ If one name <var>A</var> is an initial prefix of another
+ name <var>AB</var> (ignoring case), then <var>B</var> must not
+ start with '<code>/</code>', as a regular file cannot have the
+ same name as a directory in POSIX.
+ For example, <code>America/New_York</code> precludes
+ <code>America/New_York/Bronx</code>.
+ </li>
+ <li>
+ Uninhabited regions like the North Pole and Bouvet Island
+ do not need locations, since local time is not defined there.
+ </li>
+ <li>
+ There should typically be at least one name for each <a
+ href="https://en.wikipedia.org/wiki/ISO_3166-1"><abbr
+ title="International Organization for Standardization">ISO</abbr>
+ 3166-1</a> officially assigned two-letter code for an inhabited
+ country or territory.
+ </li>
+ <li>
+ If all the clocks in a region have agreed since 1970,
+ do not bother to include more than one location
+ even if subregions' clocks disagreed before 1970.
+ Otherwise these tables would become annoyingly large.
+ </li>
+ <li>
+ If a name is ambiguous, use a less ambiguous alternative;
+ e.g., many cities are named San José and Georgetown, so
+ prefer <code>America/Costa_Rica</code> to
+ <code>America/San_Jose</code> and <code>America/Guyana</code>
+ to <code>America/Georgetown</code>.
+ </li>
+ <li>
+ Keep locations compact.
+ Use cities or small islands, not countries or regions, so that any
+ future changes do not split individual locations into different
+ <code><abbr>tz</abbr></code> regions.
+ E.g., prefer <code>Europe/Paris</code> to <code>Europe/France</code>,
+ since
+ <a href="https://en.wikipedia.org/wiki/Time_in_France#History">France
+ has had multiple time zones</a>.
+ </li>
+ <li>
+ Use mainstream English spelling, e.g., prefer
+ <code>Europe/Rome</code> to <code>Europe/Roma</code>, and
+ prefer <code>Europe/Athens</code> to the Greek
+ <code>Europe/Αθήνα</code> or the Romanized
+ <code>Europe/Athína</code>.
+ The POSIX file name restrictions encourage this guideline.
+ </li>
+ <li>
+ Use the most populous among locations in a region,
+ e.g., prefer <code>Asia/Shanghai</code> to
+ <code>Asia/Beijing</code>.
+ Among locations with similar populations, pick the best-known
+ location, e.g., prefer <code>Europe/Rome</code> to
+ <code>Europe/Milan</code>.
+ </li>
+ <li>
+ Use the singular form, e.g., prefer <code>Atlantic/Canary</code> to
+ <code>Atlantic/Canaries</code>.
+ </li>
+ <li>
+ Omit common suffixes like '<code>_Islands</code>' and
+ '<code>_City</code>', unless that would lead to ambiguity.
+ E.g., prefer <code>America/Cayman</code> to
+ <code>America/Cayman_Islands</code> and
+ <code>America/Guatemala</code> to
+ <code>America/Guatemala_City</code>, but prefer
+ <code>America/Mexico_City</code> to
+ <code>America/Mexico</code>
+ because <a href="https://en.wikipedia.org/wiki/Time_in_Mexico">the
+ country of Mexico has several time zones</a>.
+ </li>
+ <li>
+ Use '<code>_</code>' to represent a space.
+ </li>
+ <li>
+ Omit '<code>.</code>' from abbreviations in names.
+ E.g., prefer <code>Atlantic/St_Helena</code> to
+ <code>Atlantic/St._Helena</code>.
+ </li>
+ <li>
+ Do not change established names if they only marginally violate
+ the above guidelines.
+ For example, do not change the existing name <code>Europe/Rome</code> to
+ <code>Europe/Milan</code> merely because Milan's population has grown
+ to be somewhat greater than Rome's.
+ </li>
+ <li>
+ If a name is changed, put its old spelling in the
+ '<code>backward</code>' file.
+ This means old spellings will continue to work.
+ </li>
+</ul>
+
+<p>
+The file '<code>zone1970.tab</code>' lists geographical locations used
+to name <code><abbr>tz</abbr></code> regions.
+It is intended to be an exhaustive list of names for geographic
+regions as described above; this is a subset of the names in the data.
+Although a '<code>zone1970.tab</code>' location's
+<a href="https://en.wikipedia.org/wiki/Longitude">longitude</a>
+corresponds to
+its <a href="https://en.wikipedia.org/wiki/Local_mean_time">local mean
+time (<abbr>LMT</abbr>)</a> offset with one hour for every 15&deg;
+east longitude, this relationship is not exact.
+</p>
+
+<p>
+Older versions of this package used a different naming scheme,
+and these older names are still supported.
+See the file '<code>backward</code>' for most of these older names
+(e.g., '<code>US/Eastern</code>' instead of '<code>America/New_York</code>').
+The other old-fashioned names still supported are
+'<code>WET</code>', '<code>CET</code>', '<code>MET</code>', and
+'<code>EET</code>' (see the file '<code>europe</code>').
+</p>
+
+<p>
+Older versions of this package defined legacy names that are
+incompatible with the first guideline of location names, but which are
+still supported.
+These legacy names are mostly defined in the file
+'<code>etcetera</code>'.
+Also, the file '<code>backward</code>' defines the legacy names
+'<code>GMT0</code>', '<code>GMT-0</code>' and '<code>GMT+0</code>',
+and the file '<code>northamerica</code>' defines the legacy names
+'<code>EST5EDT</code>', '<code>CST6CDT</code>',
+'<code>MST7MDT</code>', and '<code>PST8PDT</code>'.
+</p>
+
+<p>
+Excluding '<code>backward</code>' should not affect the other data.
+If '<code>backward</code>' is excluded, excluding
+'<code>etcetera</code>' should not affect the remaining data.
+</p>
+</section>
+
+<section>
+ <h2 id="abbreviations">Time zone abbreviations</h2>
+<p>
+When this package is installed, it generates time zone abbreviations
+like '<code>EST</code>' to be compatible with human tradition and POSIX.
+Here are the general guidelines used for choosing time zone abbreviations,
+in decreasing order of importance:
+</p>
+
+<ul>
+ <li>
+ Use three to six characters that are ASCII alphanumerics or
+ '<code>+</code>' or '<code>-</code>'.
+ Previous editions of this database also used characters like
+ space and '<code>?</code>', but these characters have a
+ special meaning to the
+ <a href="https://en.wikipedia.org/wiki/Unix_shell">UNIX shell</a>
+ and cause commands like
+ '<code><a href="http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set">set</a>
+ `<a href="http://pubs.opengroup.org/onlinepubs/9699919799/utilities/date.html">date</a>`</code>'
+ to have unexpected effects.
+ Previous editions of this guideline required upper-case letters, but the
+ Congressman who introduced
+ <a href="https://en.wikipedia.org/wiki/Chamorro_Time_Zone">Chamorro
+ Standard Time</a> preferred "ChST", so lower-case letters are now
+ allowed.
+ Also, POSIX from 2001 on relaxed the rule to allow '<code>-</code>',
+ '<code>+</code>', and alphanumeric characters from the portable
+ character set in the current locale.
+ In practice ASCII alphanumerics and '<code>+</code>' and
+ '<code>-</code>' are safe in all locales.
+
+ <p>
+ In other words, in the C locale the POSIX extended regular
+ expression <code>[-+[:alnum:]]{3,6}</code> should match the
+ abbreviation.
+ This guarantees that all abbreviations could have been specified by a
+ POSIX <code>TZ</code> string.
+ </p>
+ </li>
+ <li>
+ Use abbreviations that are in common use among English-speakers,
+ e.g., 'EST' for Eastern Standard Time in North America.
+ We assume that applications translate them to other languages
+ as part of the normal localization process; for example,
+ a French application might translate 'EST' to 'HNE'.
+
+ <p>
+ <small>These abbreviations (for standard/daylight/etc. time) are:
+ ACST/ACDT Australian Central,
+ AST/ADT/APT/AWT/ADDT Atlantic,
+ AEST/AEDT Australian Eastern,
+ AHST/AHDT Alaska-Hawaii,
+ AKST/AKDT Alaska,
+ AWST/AWDT Australian Western,
+ BST/BDT Bering,
+ CAT/CAST Central Africa,
+ CET/CEST/CEMT Central European,
+ ChST Chamorro,
+ CST/CDT/CWT/CPT/CDDT Central [North America],
+ CST/CDT China,
+ GMT/BST/IST/BDST Greenwich,
+ EAT East Africa,
+ EST/EDT/EWT/EPT/EDDT Eastern [North America],
+ EET/EEST Eastern European,
+ GST Guam,
+ HST/HDT Hawaii,
+ HKT/HKST Hong Kong,
+ IST India,
+ IST/GMT Irish,
+ IST/IDT/IDDT Israel,
+ JST/JDT Japan,
+ KST/KDT Korea,
+ MET/MEST Middle European (a backward-compatibility alias for
+ Central European),
+ MSK/MSD Moscow,
+ MST/MDT/MWT/MPT/MDDT Mountain,
+ NST/NDT/NWT/NPT/NDDT Newfoundland,
+ NST/NDT/NWT/NPT Nome,
+ NZMT/NZST New Zealand through 1945,
+ NZST/NZDT New Zealand 1946&ndash;present,
+ PKT/PKST Pakistan,
+ PST/PDT/PWT/PPT/PDDT Pacific,
+ SAST South Africa,
+ SST Samoa,
+ WAT/WAST West Africa,
+ WET/WEST/WEMT Western European,
+ WIB Waktu Indonesia Barat,
+ WIT Waktu Indonesia Timur,
+ WITA Waktu Indonesia Tengah,
+ YST/YDT/YWT/YPT/YDDT Yukon</small>.
+ </p>
+ </li>
+ <li>
+ <p>
+ For times taken from a city's longitude, use the
+ traditional <var>x</var>MT notation.
+ The only abbreviation like this in current use is '<abbr>GMT</abbr>'.
+ The others are for timestamps before 1960,
+ except that Monrovia Mean Time persisted until 1972.
+ Typically, numeric abbreviations (e.g., '<code>-</code>004430' for
+ MMT) would cause trouble here, as the numeric strings would exceed
+ the POSIX length limit.
+ </p>
+
+ <p>
+ <small>These abbreviations are:
+ AMT Amsterdam, Asunción, Athens;
+ BMT Baghdad, Bangkok, Batavia, Bern, Bogotá, Bridgetown, Brussels,
+ Bucharest;
+ CMT Calamarca, Caracas, Chisinau, Colón, Copenhagen, Córdoba;
+ DMT Dublin/Dunsink;
+ EMT Easter;
+ FFMT Fort-de-France;
+ FMT Funchal;
+ GMT Greenwich;
+ HMT Havana, Helsinki, Horta, Howrah;
+ IMT Irkutsk, Istanbul;
+ JMT Jerusalem;
+ KMT Kaunas, Kiev, Kingston;
+ LMT Lima, Lisbon, local, Luanda;
+ MMT Macassar, Madras, Malé, Managua, Minsk, Monrovia, Montevideo,
+ Moratuwa, Moscow;
+ PLMT Phù Liễn;
+ PMT Paramaribo, Paris, Perm, Pontianak, Prague;
+ PMMT Port Moresby;
+ QMT Quito;
+ RMT Rangoon, Riga, Rome;
+ SDMT Santo Domingo;
+ SJMT San José;
+ SMT Santiago, Simferopol, Singapore, Stanley;
+ TBMT Tbilisi;
+ TMT Tallinn, Tehran;
+ WMT Warsaw</small>.
+ </p>
+
+ <p>
+ <small>A few abbreviations also follow the pattern that
+ <abbr>GMT<abbr>/<abbr>BST</abbr> established for time in the UK.
+ They are:
+ CMT/BST for Calamarca Mean Time and Bolivian Summer Time
+ 1890&ndash;1932,
+ DMT/IST for Dublin/Dunsink Mean Time and Irish Summer Time
+ 1880&ndash;1916,
+ MMT/MST/MDST for Moscow 1880&ndash;1919, and
+ RMT/LST for Riga Mean Time and Latvian Summer time 1880&ndash;1926.
+ An extra-special case is SET for Swedish Time (<em>svensk
+ normaltid</em>) 1879&ndash;1899, 3&deg; west of the Stockholm
+ Observatory.</small>
+ </p>
+ </li>
+ <li>
+ Use '<abbr>LMT</abbr>' for local mean time of locations before the
+ introduction of standard time; see "<a href="#scope">Scope of the
+ <code><abbr>tz</abbr></code> database</a>".
+ </li>
+ <li>
+ If there is no common English abbreviation, use numeric offsets like
+ <code>-</code>05 and <code>+</code>0830 that are generated
+ by <code>zic</code>'s <code>%z</code> notation.
+ </li>
+ <li>
+ Use current abbreviations for older timestamps to avoid confusion.
+ For example, in 1910 a common English abbreviation for time
+ in central Europe was 'MEZ' (short for both "Middle European
+ Zone" and for "Mitteleuropäische Zeit" in German).
+ Nowadays 'CET' ("Central European Time") is more common in
+ English, and the database uses 'CET' even for circa-1910
+ timestamps as this is less confusing for modern users and avoids
+ the need for determining when 'CET' supplanted 'MEZ' in common
+ usage.
+ </li>
+ <li>
+ Use a consistent style in a <code><abbr>tz</abbr></code> region's history.
+ For example, if history tends to use numeric
+ abbreviations and a particular entry could go either way, use a
+ numeric abbreviation.
+ </li>
+ <li>
+ Use
+ <a href="https://en.wikipedia.org/wiki/Universal_Time">Universal Time</a>
+ (<abbr>UT</abbr>) (with time zone abbreviation '<code>-</code>00') for
+ 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://tools.ietf.org/html/rfc3339">Internet
+ <abbr title="Request For Comments">RFC 3339</a>.
+ </li>
+</ul>
+
+<p>
+Application writers should note that these abbreviations are ambiguous
+in practice: e.g., 'CST' means one thing in China and something else
+in North America, and 'IST' can refer to time in India, Ireland or
+Israel.
+To avoid ambiguity, use numeric <abbr>UT</abbr> offsets like
+'<code>-</code>0600' instead of time zone abbreviations like 'CST'.
+</p>
+</section>
+
+<section>
+ <h2 id="accuracy">Accuracy of the <code><abbr>tz</abbr></code> database</h2>
+<p>
+The <code><abbr>tz</abbr></code> database is not authoritative, and it
+surely has errors.
+Corrections are welcome and encouraged; see the file <code>CONTRIBUTING</code>.
+Users requiring authoritative data should consult national standards
+bodies and the references cited in the database's comments.
+</p>
+
+<p>
+Errors in the <code><abbr>tz</abbr></code> database arise from many sources:
+</p>
+
+<ul>
+ <li>
+ The <code><abbr>tz</abbr></code> database predicts future
+ timestamps, and current predictions
+ will be incorrect after future governments change the rules.
+ For example, if today someone schedules a meeting for 13:00 next
+ October 1, Casablanca time, and tomorrow Morocco changes its
+ daylight saving rules, software can mess up after the rule change
+ if it blithely relies on conversions made before the change.
+ </li>
+ <li>
+ The pre-1970 entries in this database cover only a tiny sliver of how
+ clocks actually behaved; the vast majority of the necessary
+ information was lost or never recorded.
+ Thousands more <code><abbr>tz</abbr></code> regions would be needed if
+ the <code><abbr>tz</abbr></code> database's scope were extended to
+ cover even just the known or guessed history of standard time; for
+ example, the current single entry for France would need to split
+ into dozens of entries, perhaps hundreds.
+ And in most of the world even this approach would be misleading
+ due to widespread disagreement or indifference about what times
+ should be observed.
+ In her 2015 book
+ <cite><a
+ href="http://www.hup.harvard.edu/catalog.php?isbn=9780674286146">The
+ Global Transformation of Time, 1870&ndash;1950</a></cite>,
+ Vanessa Ogle writes
+ "Outside of Europe and North America there was no system of time
+ zones at all, often not even a stable landscape of mean times,
+ prior to the middle decades of the twentieth century".
+ See: Timothy Shenk, <a
+href="https://www.dissentmagazine.org/blog/booked-a-global-history-of-time-vanessa-ogle">Booked:
+ A Global History of Time</a>. <cite>Dissent</cite> 2015-12-17.
+ </li>
+ <li>
+ Most of the pre-1970 data entries come from unreliable sources, often
+ astrology books that lack citations and whose compilers evidently
+ invented entries when the true facts were unknown, without
+ reporting which entries were known and which were invented.
+ These books often contradict each other or give implausible entries,
+ and on the rare occasions when they are checked they are
+ typically found to be incorrect.
+ </li>
+ <li>
+ For the UK the <code><abbr>tz</abbr></code> database relies on
+ years of first-class work done by
+ Joseph Myers and others; see
+ "<a href="https://www.polyomino.org.uk/british-time/">History of
+ legal time in Britain</a>".
+ Other countries are not done nearly as well.
+ </li>
+ <li>
+ Sometimes, different people in the same city maintain clocks
+ that differ significantly.
+ Historically, railway time was used by railroad companies (which
+ did not always
+ agree with each other), church-clock time was used for birth
+ certificates, etc.
+ More recently, competing political groups might disagree about
+ clock settings. Often this is merely common practice, but
+ sometimes it is set by law.
+ For example, from 1891 to 1911 the <abbr>UT</abbr> offset in France
+ was legally <abbr>UT</abbr> +00:09:21 outside train stations and
+ <abbr>UT</abbr> +00:04:21 inside. Other examples include
+ Chillicothe in 1920, Palm Springs in 1946/7, and Jerusalem and
+ Ürümqi to this day.
+ </li>
+ <li>
+ Although a named location in the <code><abbr>tz</abbr></code>
+ database stands for the containing region, its pre-1970 data
+ entries are often accurate for only a small subset of that region.
+ For example, <code>Europe/London</code> stands for the United
+ Kingdom, but its pre-1847 times are valid only for locations that
+ have London's exact meridian, and its 1847 transition
+ to <abbr>GMT</abbr> is known to be valid only for the L&amp;NW and
+ the Caledonian railways.
+ </li>
+ <li>
+ The <code><abbr>tz</abbr></code> database does not record the
+ earliest time for which a <code><abbr>tz</abbr></code> region's
+ data entries are thereafter valid for every location in the region.
+ For example, <code>Europe/London</code> is valid for all locations
+ in its region after <abbr>GMT</abbr> was made the standard time,
+ but the date of standardization (1880-08-02) is not in the
+ <code><abbr>tz</abbr></code> database, other than in commentary.
+ For many <code><abbr>tz</abbr></code> regions the earliest time of
+ validity is unknown.
+ </li>
+ <li>
+ The <code><abbr>tz</abbr></code> database does not record a
+ region's boundaries, and in many cases the boundaries are not known.
+ For example, the <code><abbr>tz</abbr></code> region
+ <code>America/Kentucky/Louisville</code> represents a region
+ around the city of Louisville, the boundaries of which are
+ unclear.
+ </li>
+ <li>
+ Changes that are modeled as instantaneous transitions in the
+ <code><abbr>tz</abbr></code>
+ database were often spread out over hours, days, or even decades.
+ </li>
+ <li>
+ Even if the time is specified by law, locations sometimes
+ deliberately flout the law.
+ </li>
+ <li>
+ Early timekeeping practices, even assuming perfect clocks, were
+ often not specified to the accuracy that the
+ <code><abbr>tz</abbr></code> database requires.
+ </li>
+ <li>
+ Sometimes historical timekeeping was specified more precisely
+ than what the <code><abbr>tz</abbr></code> code can handle.
+ For example, from 1909 to 1937 <a
+ href="https://www.staff.science.uu.nl/~gent0113/wettijd/wettijd.htm"
+ hreflang="nl">Netherlands clocks</a> were legally Amsterdam Mean
+ Time (estimated to be <abbr>UT</abbr>
+ +00:19:32.13), but the <code><abbr>tz</abbr></code>
+ code cannot represent the fractional second.
+ In practice these old specifications were rarely if ever
+ implemented to subsecond precision.
+ </li>
+ <li>
+ Even when all the timestamp transitions recorded by the
+ <code><abbr>tz</abbr></code> database are correct, the
+ <code><abbr>tz</abbr></code> rules that generate them may not
+ faithfully reflect the historical rules.
+ For example, from 1922 until World War II the UK moved clocks
+ forward the day following the third Saturday in April unless that
+ was Easter, in which case it moved clocks forward the previous
+ Sunday.
+ Because the <code><abbr>tz</abbr></code> database has no
+ way to specify Easter, these exceptional years are entered as
+ separate <code><abbr>tz</abbr> Rule</code> lines, even though the
+ legal rules did not change.
+ </li>
+ <li>
+ The <code><abbr>tz</abbr></code> database models pre-standard time
+ using the <a
+ href="https://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar">proleptic
+ Gregorian calendar</a> and local mean time, but many people used
+ other calendars and other timescales.
+ For example, the Roman Empire used
+ the <a href="https://en.wikipedia.org/wiki/Julian_calendar">Julian
+ calendar</a>,
+ and <a href="https://en.wikipedia.org/wiki/Roman_timekeeping">Roman
+ timekeeping</a> had twelve varying-length daytime hours with a
+ non-hour-based system at night.
+ </li>
+ <li>
+ Early clocks were less reliable, and data entries do not represent
+ clock error.
+ </li>
+ <li>
+ The <code><abbr>tz</abbr></code> database assumes Universal Time
+ (<abbr>UT</abbr>) as an origin, even though <abbr>UT</abbr> is not
+ standardized for older timestamps.
+ In the <code><abbr>tz</abbr></code> database commentary,
+ <abbr>UT</abbr> denotes a family of time standards that includes
+ Coordinated Universal Time (<abbr>UTC</abbr>) along with other
+ variants such as <abbr>UT1</abbr> and <abbr>GMT</abbr>,
+ with days starting at midnight.
+ Although <abbr>UT</abbr> equals <abbr>UTC</abbr> for modern
+ timestamps, <abbr>UTC</abbr> was not defined until 1960, so
+ commentary uses the more-general abbreviation <abbr>UT</abbr> for
+ timestamps that might predate 1960.
+ Since <abbr>UT</abbr>, <abbr>UT1</abbr>, etc. disagree slightly,
+ and since pre-1972 <abbr>UTC</abbr> seconds varied in length,
+ interpretation of older timestamps can be problematic when
+ subsecond accuracy is needed.
+ </li>
+ <li>
+ Civil time was not based on atomic time before 1972, and we do not
+ know the history of
+ <a href="https://en.wikipedia.org/wiki/Earth's_rotation">earth's
+ rotation</a> accurately enough to map <a
+ href="https://en.wikipedia.org/wiki/International_System_of_Units"><abbr
+ title="International System of Units">SI</abbr></a> seconds to
+ historical <a href="https://en.wikipedia.org/wiki/Solar_time">solar time</a>
+ to more than about one-hour accuracy.
+ See: Stephenson FR, Morrison LV, Hohenkerk CY.
+ <a href="http://dx.doi.org/10.1098/rspa.2016.0404">Measurement of
+ the Earth's rotation: 720 BC to AD 2015</a>.
+ <cite>Proc Royal Soc A</cite>. 2016 Dec 7;472:20160404.
+ Also see: Espenak F. <a
+ href="https://eclipse.gsfc.nasa.gov/SEhelp/uncertainty2004.html">Uncertainty
+ in Delta T (ΔT)</a>.
+ </li>
+ <li>
+ The relationship between POSIX time (that is, <abbr>UTC</abbr> but
+ ignoring <a href="https://en.wikipedia.org/wiki/Leap_second">leap
+ seconds</a>) and <abbr>UTC</abbr> is not agreed upon after 1972.
+ Although the POSIX
+ clock officially stops during an inserted leap second, at least one
+ proposed standard has it jumping back a second instead; and in
+ practice POSIX clocks more typically either progress glacially during
+ a leap second, or are slightly slowed while near a leap second.
+ </li>
+ <li>
+ The <code><abbr>tz</abbr></code> database does not represent how
+ uncertain its information is.
+ Ideally it would contain information about when data entries are
+ incomplete or dicey.
+ Partial temporal knowledge is a field of active research, though,
+ and it is not clear how to apply it here.
+ </li>
+</ul>
+
+<p>
+In short, many, perhaps most, of the <code><abbr>tz</abbr></code>
+database's pre-1970 and future timestamps are either wrong or
+misleading.
+Any attempt to pass the
+<code><abbr>tz</abbr></code> database off as the definition of time
+should be unacceptable to anybody who cares about the facts.
+In particular, the <code><abbr>tz</abbr></code> database's
+<abbr>LMT</abbr> offsets should not be considered meaningful, and
+should not prompt creation of <code><abbr>tz</abbr></code> regions
+merely because two locations
+differ in <abbr>LMT</abbr> or transitioned to standard time at
+different dates.
+</p>
+</section>
+
+<section>
+ <h2 id="functions">Time and date functions</h2>
+<p>
+The <code><abbr>tz</abbr></code> code contains time and date functions
+that are upwards compatible with those of POSIX.
+Code compatible with this package is already
+<a href="tz-link.html#tzdb">part of many platforms</a>, where the
+primary use of this package is to update obsolete time-related files.
+To do this, you may need to compile the time zone compiler
+'<code>zic</code>' supplied with this package instead of using the
+system '<code>zic</code>', since the format of <code>zic</code>'s
+input is occasionally extended, and a platform may still be shipping
+an older <code>zic</code>.
+</p>
+
+<h3 id="POSIX">POSIX properties and limitations</h3>
+<ul>
+ <li>
+ <p>
+ In POSIX, time display in a process is controlled by the
+ environment variable <code>TZ</code>.
+ Unfortunately, the POSIX
+ <code>TZ</code> string takes a form that is hard to describe and
+ is error-prone in practice.
+ Also, POSIX <code>TZ</code> strings cannot deal with daylight
+ saving time rules not based on the Gregorian calendar (as in
+ Iran), or with situations where more than two time zone
+ abbreviations or <abbr>UT</abbr> offsets are used in an area.
+ </p>
+
+ <p>
+ The POSIX <code>TZ</code> string takes the following form:
+ </p>
+
+ <p>
+ <var>stdoffset</var>[<var>dst</var>[<var>offset</var>][<code>,</code><var>date</var>[<code>/</code><var>time</var>]<code>,</code><var>date</var>[<code>/</code><var>time</var>]]]
+ </p>
+
+ <p>
+ where:
+ </p>
+
+ <dl>
+ <dt><var>std</var> and <var>dst</var></dt><dd>
+ are 3 or more characters specifying the standard
+ and daylight saving time (<abbr>DST</abbr>) zone names.
+ Starting with POSIX.1-2001, <var>std</var> and <var>dst</var>
+ may also be in a quoted form like '<code>&lt;+09&gt;</code>';
+ this allows "<code>+</code>" and "<code>-</code>" in the names.
+ </dd>
+ <dt><var>offset</var></dt><dd>
+ is of the form
+ '<code>[&plusmn;]<var>hh</var>:[<var>mm</var>[:<var>ss</var>]]</code>'
+ and specifies the offset west of <abbr>UT</abbr>.
+ '<var>hh</var>' may be a single digit;
+ 0&le;<var>hh</var>&le;24.
+ The default <abbr>DST</abbr> offset is one hour ahead of
+ standard time.
+ </dd>
+ <dt><var>date</var>[<code>/</code><var>time</var>]<code>,</code><var>date</var>[<code>/</code><var>time</var>]</dt><dd>
+ specifies the beginning and end of <abbr>DST</abbr>.
+ If this is absent, the system supplies its own ruleset
+ for <abbr>DST</abbr>, and its rules can differ from year to year;
+ typically <abbr>US</abbr> <abbr>DST</abbr> rules are used.
+ </dd>
+ <dt><var>time</var></dt><dd>
+ takes the form
+ '<var>hh</var><code>:</code>[<var>mm</var>[<code>:</code><var>ss</var>]]'
+ and defaults to 02:00.
+ This is the same format as the offset, except that a
+ leading '<code>+</code>' or '<code>-</code>' is not allowed.
+ </dd>
+ <dt><var>date</var></dt><dd>
+ takes one of the following forms:
+ <dl>
+ <dt>J<var>n</var> (1&le;<var>n</var>&le;365)</dt><dd>
+ origin-1 day number not counting February 29
+ </dd>
+ <dt><var>n</var> (0&le;<var>n</var>&le;365)</dt><dd>
+ origin-0 day number counting February 29 if present
+ </dd>
+ <dt><code>M</code><var>m</var><code>.</code><var>n</var><code>.</code><var>d</var>
+ (0[Sunday]&le;<var>d</var>&le;6[Saturday], 1&le;<var>n</var>&le;5,
+ 1&le;<var>m</var>&le;12)</dt><dd>
+ for the <var>d</var>th day of week <var>n</var> of
+ month <var>m</var> of the year, where week 1 is the first
+ week in which day <var>d</var> appears, and
+ '<code>5</code>' stands for the last week in which
+ day <var>d</var> appears (which may be either the 4th or
+ 5th week).
+ Typically, this is the only useful form; the <var>n</var>
+ and <code>J</code><var>n</var> forms are rarely used.
+ </dd>
+ </dl>
+ </dd>
+ </dl>
+
+ <p>
+ Here is an example POSIX <code>TZ</code> string for New
+ Zealand after 2007.
+ It says that standard time (<abbr>NZST</abbr>) is 12 hours ahead
+ of <abbr>UT</abbr>, and that daylight saving time
+ (<abbr>NZDT</abbr>) is observed from September's last Sunday at
+ 02:00 until April's first Sunday at 03:00:
+ </p>
+
+ <pre><code>TZ='NZST-12NZDT,M9.5.0,M4.1.0/3'</code></pre>
+
+ <p>
+ This POSIX <code>TZ</code> string is hard to remember, and
+ mishandles some timestamps before 2008.
+ With this package you can use this instead:
+ </p>
+
+ <pre><code>TZ='Pacific/Auckland'</code></pre>
+ </li>
+ <li>
+ POSIX does not define the exact meaning of <code>TZ</code> values like
+ "<code>EST5EDT</code>".
+ Typically the current <abbr>US</abbr> <abbr>DST</abbr> rules
+ are used to interpret such values, but this means that the
+ <abbr>US</abbr> <abbr>DST</abbr> rules are compiled into each
+ program that does time conversion.
+ This means that when
+ <abbr>US</abbr> time conversion rules change (as in the United
+ States in 1987), all programs that do time conversion must be
+ recompiled to ensure proper results.
+ </li>
+ <li>
+ The <code>TZ</code> environment variable is process-global, which
+ makes it hard to write efficient, thread-safe applications that
+ need access to multiple time zone rulesets.
+ </li>
+ <li>
+ In POSIX, there is no tamper-proof way for a process to learn the
+ system's best idea of local wall clock.
+ (This is important for applications that an administrator wants
+ used only at certain times &ndash; without regard to whether the
+ user has fiddled the
+ <code>TZ</code> environment variable.
+ While an administrator can "do everything in <abbr>UT</abbr>" to
+ get around the problem, doing so is inconvenient and precludes
+ handling daylight saving time shifts - as might be required to
+ limit phone calls to off-peak hours.)
+ </li>
+ <li>
+ POSIX provides no convenient and efficient way to determine
+ the <abbr>UT</abbr> offset and time zone abbreviation of arbitrary
+ timestamps, particularly for <code><abbr>tz</abbr></code> regions
+ that do not fit into the POSIX model.
+ </li>
+ <li>
+ POSIX requires that systems ignore leap seconds.
+ </li>
+ <li>
+ The <code><abbr>tz</abbr></code> code attempts to support all the
+ <code>time_t</code> implementations allowed by POSIX.
+ The <code>time_t</code> type represents a nonnegative count of seconds
+ since 1970-01-01 00:00:00 <abbr>UTC</abbr>, ignoring leap seconds.
+ In practice, <code>time_t</code> is usually a signed 64- or 32-bit
+ integer; 32-bit signed <code>time_t</code> values stop working after
+ 2038-01-19 03:14:07 <abbr>UTC</abbr>, so new implementations these
+ days typically use a signed 64-bit integer.
+ Unsigned 32-bit integers are used on one or two platforms, and 36-bit
+ and 40-bit integers are also used occasionally.
+ Although earlier POSIX versions allowed <code>time_t</code> to be a
+ floating-point type, this was not supported by any practical systems,
+ and POSIX.1-2013 and the <code><abbr>tz</abbr></code> code both
+ require <code>time_t</code> to be an integer type.
+ </li>
+</ul>
+
+<h3 id="POSIX-extensions">Extensions to POSIX in the
+<code><abbr>tz</abbr></code> code</h3>
+<ul>
+ <li>
+ <p>
+ The <code>TZ</code> environment variable is used in generating
+ the name of a binary file from which time-related information is read
+ (or is interpreted à la POSIX); <code>TZ</code> is no longer
+ constrained to be a three-letter time zone
+ abbreviation followed by a number of hours and an optional three-letter
+ daylight time zone abbreviation.
+ The daylight saving time rules to be used for a
+ particular <code><abbr>tz</abbr></code> region are encoded in the
+ binary file; the format of the file
+ allows U.S., Australian, and other rules to be encoded, and
+ allows for situations where more than two time zone
+ abbreviations are used.
+ </p>
+ <p>
+ It was recognized that allowing the <code>TZ</code> environment
+ variable to take on values such as '<code>America/New_York</code>'
+ might cause "old" programs (that expect <code>TZ</code> to have a
+ certain form) to operate incorrectly; consideration was given to using
+ some other environment variable (for example, <code>TIMEZONE</code>)
+ to hold the string used to generate the binary file's name.
+ In the end, however, it was decided to continue using
+ <code>TZ</code>: it is widely used for time zone purposes;
+ separately maintaining both <code>TZ</code>
+ and <code>TIMEZONE</code> seemed a nuisance; and systems where
+ "new" forms of <code>TZ</code> might cause problems can simply
+ use <code>TZ</code> values such as "<code>EST5EDT</code>" which
+ can be used both by "new" programs (à la POSIX) and "old"
+ programs (as zone names and offsets).
+ </p>
+ </li>
+ <li>
+ The code supports platforms with a <abbr>UT</abbr> offset member
+ in <code>struct tm</code>, e.g., <code>tm_gmtoff</code>.
+ </li>
+ <li>
+ The code supports platforms with a time zone abbreviation member in
+ <code>struct tm</code>, e.g., <code>tm_zone</code>.
+ </li>
+ <li>
+ Functions <code>tzalloc</code>, <code>tzfree</code>,
+ <code>localtime_rz</code>, and <code>mktime_z</code> for
+ more-efficient thread-safe applications that need to use multiple
+ time zone rulesets.
+ The <code>tzalloc</code> and <code>tzfree</code> functions
+ allocate and free objects of type <code>timezone_t</code>,
+ and <code>localtime_rz</code> and <code>mktime_z</code> are
+ like <code>localtime_r</code> and <code>mktime</code> with an
+ extra <code>timezone_t</code> argument.
+ The functions were inspired by <a href="https://netbsd.org/">NetBSD</a>.
+ </li>
+ <li>
+ A function <code>tzsetwall</code> has been added to arrange for the
+ system's best approximation to local wall clock time to be delivered
+ by subsequent calls to <code>localtime</code>.
+ Source code for portable applications that "must" run on local wall
+ clock time should call <code>tzsetwall</code>;
+ if such code is moved to "old" systems that do not
+ provide <code>tzsetwall</code>, you will not be able to generate an
+ executable program.
+ (These functions also arrange for local wall clock time to
+ be used if <code>tzset</code> is called &ndash; directly or
+ indirectly &ndash; and there is no <code>TZ</code> environment
+ variable; portable applications should not, however, rely on this
+ behavior since it is not the way <a
+ href="https://en.wikipedia.org/wiki/UNIX_System_V#SVR2"><abbr>SVR2</abbr></a>
+ systems behave.)
+ </li>
+ <li>
+ Negative <code>time_t</code> values are supported, on systems
+ where <code>time_t</code> is signed.
+ </li>
+ <li>
+ These functions can account for leap seconds, thanks to Bradley White.
+ </li>
+</ul>
+
+<h3 id="vestigial">POSIX features no longer needed</h3>
+<p>
+POSIX and <a href="https://en.wikipedia.org/wiki/ISO_C"><abbr>ISO</abbr> C</a>
+define some <a href="https://en.wikipedia.org/wiki/API"><abbr
+title="application programming interface">API</abbr>s</a> that are vestigial:
+they are not needed, and are relics of a too-simple model that does
+not suffice to handle many real-world timestamps.
+Although the <code><abbr>tz</abbr></code> code supports these
+vestigial <abbr>API</abbr>s for backwards compatibility, they should
+be avoided in portable applications.
+The vestigial <abbr>API</abbr>s are:
+</p>
+<ul>
+ <li>
+ The POSIX <code>tzname</code> variable does not suffice and is no
+ longer needed.
+ To get a timestamp's time zone abbreviation, consult
+ the <code>tm_zone</code> member if available; otherwise,
+ use <code>strftime</code>'s <code>"%Z"</code> conversion
+ specification.
+ </li>
+ <li>
+ The POSIX <code>daylight</code> and <code>timezone</code>
+ variables do not suffice and are no longer needed.
+ To get a timestamp's <abbr>UT</abbr> offset, consult
+ the <code>tm_gmtoff</code> member if available; otherwise,
+ subtract values returned by <code>localtime</code>
+ and <code>gmtime</code> using the rules of the Gregorian calendar,
+ or use <code>strftime</code>'s <code>"%z"</code> conversion
+ specification if a string like <code>"+0900"</code> suffices.
+ </li>
+ <li>
+ 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.
+ 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, this
+ disambiguation does not work when standard time itself jumps back,
+ which can occur when a location changes to a time zone with a
+ lesser <abbr>UT</abbr> offset.
+ </li>
+</ul>
+
+<h3 id="other-portability">Other portability notes</h3>
+<ul>
+ <li>
+ The <a href="https://en.wikipedia.org/wiki/Version_7_Unix">7th Edition
+ UNIX</a> <code>timezone</code> function is not present in this
+ package; it is impossible to reliably map <code>timezone</code>'s
+ arguments (a "minutes west of <abbr>GMT</abbr>" value and a
+ "daylight saving time in effect" flag) to a time zone
+ abbreviation, and we refuse to guess.
+ 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>
+ (if <code>HAVE_TZNAME</code> is defined) to learn the correct time
+ zone abbreviation to use.
+ </li>
+ <li>
+ The <a
+ href="https://en.wikipedia.org/wiki/History_of_the_Berkeley_Software_Distribution#4.2BSD"><abbr>4.2BSD</abbr></a>
+ <code>gettimeofday</code> function is not
+ used in this package.
+ This formerly let users obtain the current <abbr>UTC</abbr> offset
+ and <abbr>DST</abbr> flag, but this functionality was removed in
+ later versions of <abbr>BSD</abbr>.
+ </li>
+ <li>
+ In <abbr>SVR2</abbr>, time conversion fails for near-minimum or
+ near-maximum <code>time_t</code> values when doing conversions
+ for places that do not use <abbr>UT</abbr>.
+ This package takes care to do these conversions correctly.
+ A comment in the source code tells how to get compatibly wrong
+ results.
+ </li>
+ <li>
+ The functions that are conditionally compiled
+ if <code>STD_INSPIRED</code> is defined should, at this point, be
+ looked on primarily as food for thought.
+ They are not in any sense "standard compatible" &ndash; some are
+ not, in fact, specified in <em>any</em> standard.
+ They do, however, represent responses of various authors to
+ standardization proposals.
+ </li>
+ <li>
+ Other time conversion proposals, in particular the one developed
+ by folks at Hewlett Packard, offer a wider selection of functions
+ that provide capabilities beyond those provided here.
+ The absence of such functions from this package is not meant to
+ discourage the development, standardization, or use of such
+ functions.
+ Rather, their absence reflects the decision to make this package
+ contain valid extensions to POSIX, to ensure its broad
+ acceptability.
+ If more powerful time conversion functions can be standardized, so
+ much the better.
+ </li>
+</ul>
+</section>
+
+<section>
+ <h2 id="stability">Interface stability</h2>
+<p>
+The <code><abbr>tz</abbr></code> code and data supply the following interfaces:
+</p>
+
+<ul>
+ <li>
+ A set of <code><abbr>tz</abbr></code> region names as per
+ "<a href="#naming">Names of time zone rulesets</a>" above.
+ </li>
+ <li>
+ Library functions described in "<a href="#functions">Time and date
+ functions</a>" above.
+ </li>
+ <li>
+ The programs <code>tzselect</code>, <code>zdump</code>,
+ and <code>zic</code>, documented in their man pages.
+ </li>
+ <li>
+ The format of <code>zic</code> input files, documented in
+ the <code>zic</code> man page.
+ </li>
+ <li>
+ The format of <code>zic</code> output files, documented in
+ the <code>tzfile</code> man page.
+ </li>
+ <li>
+ The format of zone table files, documented in <code>zone1970.tab</code>.
+ </li>
+ <li>
+ The format of the country code file, documented in <code>iso3166.tab</code>.
+ </li>
+ <li>
+ The version number of the code and data, as the first line of
+ the text file '<code>version</code>' in each release.
+ </li>
+</ul>
+
+<p>
+Interface changes in a release attempt to preserve compatibility with
+recent releases.
+For example, <code><abbr>tz</abbr></code> data files typically do not
+rely on recently-added <code>zic</code> features, so that users can
+run older <code>zic</code> versions to process newer data files.
+<a href="tz-link.html#download">Downloading
+the <code><abbr>tz</abbr></code> database</a> describes how releases
+are tagged and distributed.
+</p>
+
+<p>
+Interfaces not listed above are less stable.
+For example, users should not rely on particular <abbr>UT</abbr>
+offsets or abbreviations for timestamps, as data entries are often
+based on guesswork and these guesses may be corrected or improved.
+</p>
+</section>
+
+<section>
+ <h2 id="calendar">Calendrical issues</h2>
+<p>
+Calendrical issues are a bit out of scope for a time zone database,
+but they indicate the sort of problems that we would run into if we
+extended the time zone database further into the past.
+An excellent resource in this area is Edward M. Reingold
+and Nachum Dershowitz, <cite><a
+href="https://www.cambridge.org/fr/academic/subjects/computer-science/computing-general-interest/calendrical-calculations-ultimate-edition-4th-edition">Calendrical
+Calculations: The Ultimate Edition</a></cite>, Cambridge University Press (2018).
+Other information and sources are given in the file '<code>calendars</code>'
+in the <code><abbr>tz</abbr></code> distribution.
+They sometimes disagree.
+</p>
+</section>
+
+<section>
+ <h2 id="planets">Time and time zones on other planets</h2>
+<p>
+Some people's work schedules
+use <a href="https://en.wikipedia.org/wiki/Timekeeping on Mars">Mars time</a>.
+Jet Propulsion Laboratory (JPL) coordinators kept Mars time on
+and off during the
+<a href="https://en.wikipedia.org/wiki/Mars_Pathfinder#End_of_mission">Mars
+Pathfinder</a> mission.
+Some of their family members also adapted to Mars time.
+Dozens of special Mars watches were built for JPL workers who kept
+Mars time during the Mars Exploration Rovers mission (2004).
+These timepieces look like normal Seikos and Citizens but use Mars
+seconds rather than terrestrial seconds.
+</p>
+
+<p>
+A Mars solar day is called a "sol" and has a mean period equal to
+about 24 hours 39 minutes 35.244 seconds in terrestrial time.
+It is divided into a conventional 24-hour clock, so each Mars second
+equals about 1.02749125 terrestrial seconds.
+</p>
+
+<p>
+The <a href="https://en.wikipedia.org/wiki/Prime_meridian">prime
+meridian</a> of Mars goes through the center of the crater
+<a href="https://en.wikipedia.org/wiki/Airy-0">Airy-0</a>, named in
+honor of the British astronomer who built the Greenwich telescope that
+defines Earth's prime meridian.
+Mean solar time on the Mars prime meridian is
+called <a href="https://en.wikipedia.org/wiki/Mars_Coordinated_Time">Mars
+Coordinated Time (<abbr>MTC</abbr>)</a>.
+</p>
+
+<p>
+Each landed mission on Mars has adopted a different reference for
+solar time keeping, so there is no real standard for Mars time zones.
+For example, the
+<a href="https://en.wikipedia.org/wiki/Mars_Exploration_Rover">Mars
+Exploration Rover</a> project (2004) defined two time zones "Local
+Solar Time A" and "Local Solar Time B" for its two missions, each zone
+designed so that its time equals local true solar time at
+approximately the middle of the nominal mission.
+Such a "time zone" is not particularly suited for any application
+other than the mission itself.
+</p>
+
+<p>
+Many calendars have been proposed for Mars, but none have achieved
+wide acceptance.
+Astronomers often use Mars Sol Date (<abbr>MSD</abbr>) which is a
+sequential count of Mars solar days elapsed since about 1873-12-29
+12:00 <abbr>GMT</abbr>.
+</p>
+
+<p>
+In our solar system, Mars is the planet with time and calendar most
+like Earth's.
+On other planets, Sun-based time and calendars would work quite
+differently.
+For example, although Mercury's
+<a href="https://en.wikipedia.org/wiki/Rotation_period">sidereal
+rotation period</a> is 58.646 Earth days, Mercury revolves around the
+Sun so rapidly that an observer on Mercury's equator would see a
+sunrise only every 175.97 Earth days, i.e., a Mercury year is 0.5 of a
+Mercury day.
+Venus is more complicated, partly because its rotation is slightly
+<a href="https://en.wikipedia.org/wiki/Retrograde_motion">retrograde</a>:
+its year is 1.92 of its days.
+Gas giants like Jupiter are trickier still, as their polar and
+equatorial regions rotate at different rates, so that the length of a
+day depends on latitude.
+This effect is most pronounced on Neptune, where the day is about 12
+hours at the poles and 18 hours at the equator.
+</p>
+
+<p>
+Although the <code><abbr>tz</abbr></code> database does not support
+time on other planets, it is documented here in the hopes that support
+will be added eventually.
+</p>
+
+<p>
+Sources for time on other planets:
+</p>
+
+<ul>
+ <li>
+ Michael Allison and Robert Schmunk,
+ "<a href="https://www.giss.nasa.gov/tools/mars24/help/notes.html">Technical
+ Notes on Mars Solar Time as Adopted by the Mars24 Sunclock</a>"
+ (2015-06-30).
+ </li>
+ <li>
+ Jia-Rui Chong,
+ "<a href="http://articles.latimes.com/2004/jan/14/science/sci-marstime14">Workdays
+ Fit for a Martian</a>", <cite>Los Angeles Times</cite>
+ (2004-01-14), pp A1, A20&ndash;A21.
+ </li>
+ <li>
+ Tom Chmielewski,
+ "<a href="https://www.theatlantic.com/technology/archive/2015/02/jet-lag-is-worse-on-mars/386033/">Jet
+ Lag Is Worse on Mars</a>", <cite>The Atlantic</cite> (2015-02-26)
+ </li>
+ <li>
+ Matt Williams,
+ "<a href="https://www.universetoday.com/37481/days-of-the-planets/">How
+ long is a day on the other planets of the solar system?</a>"
+ (2017-04-27).
+ </li>
+</ul>
+</section>
+
+<footer>
+ <hr>
+ This file is in the public domain, so clarified as of 2009-05-17 by
+ Arthur David Olson.
+</footer>
+</body>
+</html>
diff --git a/time2posix.3 b/time2posix.3
new file mode 100644
index 000000000000..e4b8e8199063
--- /dev/null
+++ b/time2posix.3
@@ -0,0 +1,129 @@
+.TH TIME2POSIX 3
+.SH NAME
+time2posix, posix2time \- convert seconds since the Epoch
+.SH SYNOPSIS
+.nf
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.B #include <time.h>
+.PP
+.B time_t time2posix(time_t t);
+.PP
+.B time_t posix2time(time_t t);
+.PP
+.B cc ... \*-ltz
+.fi
+.SH DESCRIPTION
+.ie '\(en'' .ds en \-
+.el .ds en \(en
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+IEEE Standard 1003.1
+(POSIX)
+requires the time_t value 536457599 to stand for 1986-12-31 23:59:59 UTC.
+This effectively implies that POSIX time_t values cannot include leap
+seconds and,
+therefore,
+that the system time must be adjusted as each leap occurs.
+.PP
+If the time package is configured with leap-second support
+enabled,
+however,
+no such adjustment is needed and
+time_t values continue to increase over leap events
+(as a true
+.q "seconds since..."
+value).
+This means that these values will differ from those required by POSIX
+by the net number of leap seconds inserted since the Epoch.
+.PP
+Typically this is not a problem as the type time_t is intended
+to be
+(mostly)
+opaque \*(en time_t values should only be obtained-from and
+passed-to functions such as
+.IR time(2) ,
+.IR localtime(3) ,
+.IR mktime(3) ,
+and
+.IR difftime(3) .
+However,
+POSIX gives an arithmetic
+expression for directly computing a time_t value from a given date/time,
+and the same relationship is assumed by some
+(usually older)
+applications.
+Any programs creating/dissecting time_t's
+using such a relationship will typically not handle intervals
+over leap seconds correctly.
+.PP
+The
+.I time2posix
+and
+.I posix2time
+functions are provided to address this time_t mismatch by converting
+between local time_t values and their POSIX equivalents.
+This is done by accounting for the number of time-base changes that
+would have taken place on a POSIX system as leap seconds were inserted
+or deleted.
+These converted values can then be used in lieu of correcting the older
+applications,
+or when communicating with POSIX-compliant systems.
+.PP
+.I Time2posix
+is single-valued.
+That is,
+every local time_t
+corresponds to a single POSIX time_t.
+.I Posix2time
+is less well-behaved:
+for a positive leap second hit the result is not unique,
+and for a negative leap second hit the corresponding
+POSIX time_t doesn't exist so an adjacent value is returned.
+Both of these are good indicators of the inferiority of the
+POSIX representation.
+.PP
+The following table summarizes the relationship between a time
+T and it's conversion to,
+and back from,
+the POSIX representation over the leap second inserted at the end of June,
+1993.
+.nf
+.ta \w'93/06/30 'u +\w'23:59:59 'u +\w'A+0 'u +\w'X=time2posix(T) 'u
+DATE TIME T X=time2posix(T) posix2time(X)
+93/06/30 23:59:59 A+0 B+0 A+0
+93/06/30 23:59:60 A+1 B+1 A+1 or A+2
+93/07/01 00:00:00 A+2 B+1 A+1 or A+2
+93/07/01 00:00:01 A+3 B+2 A+3
+
+A leap second deletion would look like...
+
+DATE TIME T X=time2posix(T) posix2time(X)
+??/06/30 23:59:58 A+0 B+0 A+0
+??/07/01 00:00:00 A+1 B+2 A+1
+??/07/01 00:00:01 A+2 B+3 A+2
+.sp
+.ce
+ [Note: posix2time(B+1) => A+0 or A+1]
+.fi
+.PP
+If leap-second support is not enabled,
+local time_t's and
+POSIX time_t's are equivalent,
+and both
+.I time2posix
+and
+.I posix2time
+degenerate to the identity function.
+.SH SEE ALSO
+difftime(3),
+localtime(3),
+mktime(3),
+time(2)
+.\" This file is in the public domain, so clarified as of
+.\" 1996-06-05 by Arthur David Olson.
diff --git a/time2posix.3.txt b/time2posix.3.txt
new file mode 100644
index 000000000000..d9db97010ebe
--- /dev/null
+++ b/time2posix.3.txt
@@ -0,0 +1,76 @@
+TIME2POSIX(3) Library Functions Manual TIME2POSIX(3)
+
+NAME
+ time2posix, posix2time - convert seconds since the Epoch
+
+SYNOPSIS
+ #include <time.h>
+
+ time_t time2posix(time_t t);
+
+ time_t posix2time(time_t t);
+
+ cc ... -ltz
+
+DESCRIPTION
+ IEEE Standard 1003.1 (POSIX) requires the time_t value 536457599 to
+ stand for 1986-12-31 23:59:59 UTC. This effectively implies that POSIX
+ time_t values cannot include leap seconds and, therefore, that the
+ system time must be adjusted as each leap occurs.
+
+ If the time package is configured with leap-second support enabled,
+ however, no such adjustment is needed and time_t values continue to
+ increase over leap events (as a true "seconds since..." value). This
+ means that these values will differ from those required by POSIX by the
+ net number of leap seconds inserted since the Epoch.
+
+ Typically this is not a problem as the type time_t is intended to be
+ (mostly) opaque - time_t values should only be obtained-from and
+ passed-to functions such as time(2), localtime(3), mktime(3), and
+ difftime(3). However, POSIX gives an arithmetic expression for
+ directly computing a time_t value from a given date/time, and the same
+ relationship is assumed by some (usually older) applications. Any
+ programs creating/dissecting time_t's using such a relationship will
+ typically not handle intervals over leap seconds correctly.
+
+ The time2posix and posix2time functions are provided to address this
+ time_t mismatch by converting between local time_t values and their
+ POSIX equivalents. This is done by accounting for the number of time-
+ base changes that would have taken place on a POSIX system as leap
+ seconds were inserted or deleted. These converted values can then be
+ used in lieu of correcting the older applications, or when
+ communicating with POSIX-compliant systems.
+
+ Time2posix is single-valued. That is, every local time_t corresponds
+ to a single POSIX time_t. Posix2time is less well-behaved: for a
+ positive leap second hit the result is not unique, and for a negative
+ leap second hit the corresponding POSIX time_t doesn't exist so an
+ adjacent value is returned. Both of these are good indicators of the
+ inferiority of the POSIX representation.
+
+ The following table summarizes the relationship between a time T and
+ it's conversion to, and back from, the POSIX representation over the
+ leap second inserted at the end of June, 1993.
+ DATE TIME T X=time2posix(T) posix2time(X)
+ 93/06/30 23:59:59 A+0 B+0 A+0
+ 93/06/30 23:59:60 A+1 B+1 A+1 or A+2
+ 93/07/01 00:00:00 A+2 B+1 A+1 or A+2
+ 93/07/01 00:00:01 A+3 B+2 A+3
+
+ A leap second deletion would look like...
+
+ DATE TIME T X=time2posix(T) posix2time(X)
+ ??/06/30 23:59:58 A+0 B+0 A+0
+ ??/07/01 00:00:00 A+1 B+2 A+1
+ ??/07/01 00:00:01 A+2 B+3 A+2
+
+ [Note: posix2time(B+1) => A+0 or A+1]
+
+ If leap-second support is not enabled, local time_t's and POSIX
+ time_t's are equivalent, and both time2posix and posix2time degenerate
+ to the identity function.
+
+SEE ALSO
+ difftime(3), localtime(3), mktime(3), time(2)
+
+ TIME2POSIX(3)
diff --git a/tz-art.html b/tz-art.html
new file mode 100644
index 000000000000..9624d8cd2292
--- /dev/null
+++ b/tz-art.html
@@ -0,0 +1,610 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="UTF-8">
+<title>Time and the Arts</title>
+</head>
+<body>
+<h1>Time and the Arts</h1>
+<h2>Documentaries</h2>
+<ul>
+<li>
+"<a href="https://www.youtube.com/watch?v=84aWtseb2-4">Daylight
+Saving Time Explained</a>" (2011; 6:39) lightly covers daylight saving
+time's theory, history, pros and cons. Among other things, it explains
+Arizona's daylight-saving enclaves quite well.</li>
+<li>
+"<a href="https://www.youtube.com/watch?v=-5wpm-gesOY">The Problem
+with Time &amp; Timezones &ndash; Computerphile</a>" (2013; 10:12) delves
+into problems that programmers have with timekeeping.</li>
+<li>
+<a href="https://www.rferl.org/a/28375932.html">All The Time In The World:
+Explaining The Mysteries Of Time Zones</a>" (2017; 2:15)
+briefly says why France has more time zones than Russia.
+<li>
+"About Time" (1962; 53 minutes) is part of the
+Bell Science extravaganza, with Frank Baxter, Richard Deacon, and Les Tremayne.
+Its advisor was Richard Feynman, and it was voiced by Mel Blanc.
+(<a href="http://www.imdb.com/title/tt0154110/">IMDb entry</a>.)</li>
+</ul>
+<h2>Movies</h2>
+<ul>
+<li>
+In the 1946 movie <em>A Matter of Life and Death</em>
+(U.S. title <em>Stairway to Heaven</em>)
+there is a reference to British Double Summer Time.
+The time does not play a large part in the plot;
+it's just a passing reference to the time when one of the
+characters was supposed to have died (but didn't).
+The IMDb page is at
+<a href="http://us.imdb.com/title/tt0038733/">
+http://us.imdb.com/title/tt0038733/
+</a>. (Dave Cantor)
+<li>
+The 1953 railway comedy movie <em>The Titfield Thunderbolt</em> includes a
+play on words on British Double Summer Time. Valentine's wife wants
+him to leave the pub and asks him, "Do you know what time it is?"
+And he, happy where he is, replies: "Yes, my love. Summer double time."
+IMDb page:
+<a href="http://us.imdb.com/title/tt0046436/">
+http://us.imdb.com/title/tt0046436/
+</a>. (Mark Brader, 2009-10-02)
+</li>
+<li>
+The premise of the 1999 caper movie <em>Entrapment</em> involves computers
+in an international banking network being shut down briefly at
+midnight in each time zone to avoid any problems at the transition
+from the year 1999 to 2000 in that zone. (Hmmmm.) If this shutdown
+is extended by 10 seconds, it will create a one-time opportunity for
+a gigantic computerized theft. To achieve this, at one location the
+crooks interfere with the microwave system supplying time signals to
+the computer, advancing the time by 0.1 second each minute over the
+last hour of 1999. (So this movie teaches us that 0.1 &times; 60 = 10.)
+IMDb page:
+<a href="http://us.imdb.com/title/tt0137494/">
+http://us.imdb.com/title/tt0137494/
+</a>. (Mark Brader, 2009-10-02)
+</li>
+<li>
+One mustn't forget the
+<a href="https://www.youtube.com/watch?v=k4EUTMPuvHo">trailer</a>
+(2014; 2:23) for the movie <em>Daylight Saving</em>.
+</li>
+</ul>
+<h2>TV episodes</h2>
+<ul>
+<li>
+An episode of <em>The Adventures of Superman</em> entitled "The Mysterious
+Cube," first aired 1958-02-24, had Superman convincing the controllers
+of the Arlington Time Signal to broadcast ahead of actual time;
+doing so got a crook trying to be declared dead to
+emerge a bit too early from the titular enclosure.
+</li>
+<li>
+"The Chimes of Big Ben", <em>The Prisoner</em>, episode 2, ITC, 1967-10-06.
+Our protagonist tumbles to
+the fraudulent nature of a Poland-to-England escape upon hearing "Big
+Ben" chiming on Polish local time.
+</li>
+<li>
+"The Susie", <em>Seinfeld</em>, season 8, episode 15, NBC, 1997-02-13.
+Kramer decides that daylight saving time
+isn't coming fast enough, so he sets his watch ahead an hour.
+</li>
+<li>
+"20 Hours in America", <em>The West Wing</em>, season 4, episodes 1&ndash;2,
+2002-09-25, contained a <a
+href="https://www.youtube.com/watch?v=-J1NHzQ1sgc">scene</a> that
+saw White House staffers stranded in Indiana; they thought they had time to
+catch Air Force One but were done in by intra-Indiana local time changes.
+</li>
+<li>
+"In what time zone would you find New York City?" was a $200 question on
+the 1999-11-13 United States airing of <em>Who Wants to Be a Millionaire?</em>,
+and "In 1883, what industry led the movement to divide the U.S. into four time
+zones?" was a $32,000 question on the 2001-05-23 United States airing of
+the same show. At this rate, the million-dollar time-zone
+question should have been asked 2002-06-04.
+</li>
+<li>
+A private jet's mid-flight change of time zones distorts Alison Dubois'
+premonition in the "We Had a Dream" episode of <em>Medium</em>
+(originally aired 2007-02-28).
+</li>
+<li>
+In the <em>30 Rock</em> episode "Anna Howard Shaw Day"
+(first broadcast 2010-02-11),
+Jack Donaghy's date realizes that a Geneva-to-New-York business phone call
+received in the evening must be fake given the difference in local times.
+</li>
+<li>
+In the "Run by the Monkeys" episode of <em>Da Vinci's Inquest</em>
+(first broadcast 2002-11-17),
+a witness in a five-year-old fire case realizes they may not have set
+their clock back when daylight saving ended on the day of the fire,
+introducing the possibility of an hour when arson might have occurred.
+</li>
+<li>
+In "The Todd Couple" episode of <em>Outsourced</em> (first aired 2011-02-10),
+Manmeet sets up Valentine's Day teledates for 6:00 and 9:00pm;
+since one is with a New Yorker and the other with a San Franciscan,
+hilarity ensues.
+(Never mind that this should be 7:30am in Mumbai, yet for some reason the show
+proceeds as though it's also mid-evening there.)
+</li>
+<li>
+In the "14 Days to Go"/"T Minus..." episode of
+<em>You, Me and the Apocalypse</em>
+(first aired 2015-11-11 in the UK, 2016-03-10 in the US),
+the success of a mission to deal with a comet
+hinges on whether or not Russia observes daylight saving time.
+(In the US, the episode first aired in the week before the switch to DST.)
+</li>
+<li>
+"The Lost Hour", <em>Eerie, Indiana</em>, episode 10, NBC, 1991-12-01.
+Despite Indiana's then-lack of DST, Marshall changes his clock with
+unusual consequences.
+See "<a
+href="https://www.avclub.com/eerie-indiana-was-a-few-dimensions-ahead-of-its-time-1819833380"><em>Eerie,
+Indiana</em> was a few dimensions ahead of its time</a>".
+</li>
+<li>
+"Time Tunnel", <em>The Adventures of Pete &amp; Pete</em>, season 2, episode 5,
+Nickelodeon, 1994-10-23.
+The two Petes travel back in time an hour on the day that DST ends.
+</li>
+<li>
+"King-Size Homer", <em>The Simpsons</em>, episode 135, Fox, 1995-11-05.
+Homer, working from home, remarks "8:58, first
+time I've ever been early for work. Except for all those daylight
+savings days. Lousy farmers."
+</li>
+<li>
+"Tracks", <em>The Good Wife</em>, season 7, episode 12,
+CBS, 2016-01-17.
+The applicability of a contract hinges on the
+time zone associated with a video timestamp.
+</li>
+<li>
+"Justice", <em>Veep</em>, season 6, episode 4, HBO, 2017-05-07.
+Jonah's inability to understand DST ends up impressing a wealthy
+backer who sets him up for a 2020 presidential run.
+</li>
+</ul>
+<h2>Books, plays, and magazines</h2>
+<ul>
+<li>
+Jules Verne, <em>Around the World in Eighty Days</em>
+(<em>Le tour du monde en quatre-vingts jours</em>), 1873.
+Wall-clock time plays a central role in the plot.
+European readers of the 1870s clearly held the U.S. press in
+deep contempt; the protagonists cross the U.S. without once
+reading a paper.
+Available versions include
+<a href="http://www.literature.org/Works/Jules-Verne/eighty">an English
+translation</a>, and
+<a href="https://fourmilab.ch/etexts/www/tdm80j">the original French</a>
+"with illustrations from the original 1873 French-language edition".
+</li>
+<li>
+Nick Enright, <em>Daylight Saving</em>, 1989.
+A fast-paced comedy about love and loneliness as the clocks turn back.
+</li>
+<li>
+Umberto Eco, <em>The Island of the Day Before</em>
+(<em>L'isola del giorno prima</em>), 1994.
+"...the story of a 17th century Italian nobleman trapped near an island
+on the International Date Line. Time and time zones play an integral
+part in the novel." (Paul Eggert, 2006-04-22)
+</li>
+<li>
+John Dunning, <a
+href="http://books.simonandschuster.com/Two-OClock-Eastern-Wartime/John-Dunning/9781439171530"><em>Two
+O'Clock, Eastern Wartime</em></a>, 2001.
+Mystery, history, daylight saving time, and old-time radio.
+</li>
+<li>
+Surrealist artist Guy Billout's work "Date Line" appeared on page 103
+of the 1999-11 <em>Atlantic Monthly</em>.
+</li>
+<li>
+"Gloom, Gloom, Go Away" by Walter Kirn appeared on page 106 of <em>Time</em>
+magazine's 2002-11-11 issue; among other things, it proposed
+year-round DST as a way of lessening wintertime despair.
+</li>
+</ul>
+<h2>Music</h2>
+<p>
+Data on recordings of "Save That Time," Russ Long, Serrob Publishing, BMI:</p>
+<table>
+<tr><td>Artist</td><td>Karrin Allyson</td></tr>
+<tr><td>CD</td><td>I Didn't Know About You</td></tr>
+<tr><td>Copyright Date</td><td>1993</td></tr>
+<tr><td>Label</td><td>Concord Jazz, Inc.</td></tr>
+<tr><td>ID</td><td>CCD-4543</td></tr>
+<tr><td>Track Time</td><td>3:44</td></tr>
+<tr><td>Personnel</td><td>Karrin Allyson, vocal;
+Russ Long, piano;
+Gerald Spaits, bass;
+Todd Strait, drums</td></tr>
+<tr><td>Notes</td><td>CD notes "additional lyric by Karrin Allyson;
+arranged by Russ Long and Karrin Allyson"</td></tr>
+<tr><td>ADO Rating</td><td>1 star</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/i-didnt-know-about-you-mw0000618657">AMG Rating</a></td><td>4 stars</td></tr>
+<tr><td>Penguin Rating</td><td>3.5 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Kevin Mahogany</td></tr>
+<tr><td>CD</td><td>Double Rainbow</td></tr>
+<tr><td>Copyright Date</td><td>1993</td></tr>
+<tr><td>Label</td><td>Enja Records</td></tr>
+<tr><td>ID</td><td>ENJ-7097 2</td></tr>
+<tr><td>Track Time</td><td>6:27</td></tr>
+<tr><td>Personnel</td><td>Kevin Mahogany, vocal;
+Kenny Barron, piano;
+Ray Drummond, bass;
+Ralph Moore, tenor saxophone;
+Lewis Nash, drums</td></tr>
+<tr><td>ADO Rating</td><td>1.5 stars</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/double-rainbow-mw0000620371">AMG Rating</a></td><td>3 stars</td></tr>
+<tr><td>Penguin Rating</td><td>3 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Joe Williams</td></tr>
+<tr><td>CD</td><td>Here's to Life</td></tr>
+<tr><td>Copyright Date</td><td>1994</td></tr>
+<tr><td>Label</td><td>Telarc International Corporation</td></tr>
+<tr><td>ID</td><td>CD-83357</td></tr>
+<tr><td>Track Time</td><td>3:58</td></tr>
+<tr><td>Personnel</td><td>Joe Williams, vocal
+The Robert Farnon [39 piece] Orchestra</td></tr>
+<tr><td>Notes</td><td>This CD is also available as part of a 3-CD package from
+Telarc, "Triple Play" (CD-83461)</td></tr>
+<tr><td>ADO Rating</td><td>black dot</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/heres-to-life-mw0000623648">AMG Rating</a></td><td>2 stars</td></tr>
+<tr><td>Penguin Rating</td><td>3 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Charles Fambrough</td></tr>
+<tr><td>CD</td><td>Keeper of the Spirit</td></tr>
+<tr><td>Copyright Date</td><td>1995</td></tr>
+<tr><td>Label</td><td>AudioQuest Music</td></tr>
+<tr><td>ID</td><td>AQ-CD1033</td></tr>
+<tr><td>Track Time</td><td>7:07</td></tr>
+<tr><td>Personnel</td><td>Charles Fambrough, bass;
+Joel Levine, tenor recorder;
+Edward Simon, piano;
+Lenny White, drums;
+Marion Simon, percussion</td></tr>
+<tr><td>ADO Rating</td><td>2 stars</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/keeper-of-the-spirit-mw0000176559">AMG Rating</a></td><td>unrated</td></tr>
+<tr><td>Penguin Rating</td><td>3 stars</td></tr>
+</table>
+<hr>
+<p>Also of note:</p>
+<table>
+<tr><td>Artist</td><td>Holly Cole Trio</td></tr>
+<tr><td>CD</td><td>Blame It On My Youth</td></tr>
+<tr><td>Copyright Date</td><td>1992</td></tr>
+<tr><td>Label</td><td>Manhattan</td></tr>
+<tr><td>ID</td><td>CDP 7 97349 2</td></tr>
+<tr><td>Total Time</td><td>37:45</td></tr>
+<tr><td>Personnel</td><td>Holly Cole, voice;
+Aaron Davis, piano;
+David Piltch, string bass</td></tr>
+<tr><td>Notes</td><td>Lyrical reference to "Eastern Standard Time" in
+Tom Waits' "Purple Avenue"</td></tr>
+<tr><td>ADO Rating</td><td>2.5 stars</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/blame-it-on-my-youth-mw0000274303">AMG Rating</a></td><td>3 stars</td></tr>
+<tr><td>Penguin Rating</td><td>unrated</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Milt Hinton</td></tr>
+<tr><td>CD</td><td>Old Man Time</td></tr>
+<tr><td>Copyright Date</td><td>1990</td></tr>
+<tr><td>Label</td><td>Chiaroscuro</td></tr>
+<tr><td>ID</td><td>CR(D) 310</td></tr>
+<tr><td>Total Time</td><td>149:38 (two CDs)</td></tr>
+<tr><td>Personnel</td><td>Milt Hinton, bass;
+Doc Cheatham, Dizzy Gillespie, Clark Terry, trumpet;
+Al Grey, trombone;
+Eddie Barefield, Joe Camel (Flip Phillips), Buddy Tate,
+clarinet and saxophone;
+John Bunch, Red Richards, Norman Simmons, Derek Smith,
+Ralph Sutton, piano;
+Danny Barker, Al Casey, guitar;
+Gus Johnson, Gerryck King, Bob Rosengarden, Jackie Williams,
+drums;
+Lionel Hampton, vibraphone;
+Cab Calloway, Joe Williams, vocal;
+Buck Clayton, arrangements</td></tr>
+<tr><td>Notes</td><td>tunes include Old Man Time, Time After Time,
+Sometimes I'm Happy,
+A Hot Time in the Old Town Tonight,
+Four or Five Times, Now's the Time,
+Time on My Hands, This Time It's Us,
+and Good Time Charlie.
+<a href="http://www.chiaroscurojazz.com/album.php?C=310">Album info</a>
+is available.</td></tr>
+<tr><td>ADO Rating</td><td>3 stars</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/old-man-time-mw0000269353">AMG Rating</a></td><td>4.5 stars</td></tr>
+<tr><td>Penguin Rating</td><td>3 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Alan Broadbent</td></tr>
+<tr><td>CD</td><td>Pacific Standard Time</td></tr>
+<tr><td>Copyright Date</td><td>1995</td></tr>
+<tr><td>Label</td><td>Concord Jazz, Inc.</td></tr>
+<tr><td>ID</td><td>CCD-4664</td></tr>
+<tr><td>Total Time</td><td>62:42</td></tr>
+<tr><td>Personnel</td><td>Alan Broadbent, piano;
+Putter Smith, Bass;
+Frank Gibson, Jr., drums</td></tr>
+<tr><td>Notes</td><td>The CD cover features an analemma for equation-of-time fans</td></tr>
+<tr><td>ADO Rating</td><td>1 star</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/pacific-standard-time-mw0000645433">AMG Rating</a></td><td>4 stars</td></tr>
+<tr><td>Penguin Rating</td><td>3.5 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Anthony Braxton/Richard Teitelbaum</td></tr>
+<tr><td>CD</td><td>Silence/Time Zones</td></tr>
+<tr><td>Copyright Date</td><td>1996</td></tr>
+<tr><td>Label</td><td>Black Lion</td></tr>
+<tr><td>ID</td><td>BLCD 760221</td></tr>
+<tr><td>Total Time</td><td>72:58</td></tr>
+<tr><td>Personnel</td><td>Anthony Braxton, sopranino and alto saxophones,
+contrebasse clarinet, miscellaneous instruments;
+Leo Smith, trumpet and miscellaneous instruments;
+Leroy Jenkins, violin and miscellaneous instruments;
+Richard Teitelbaum, modular moog and micromoog synthesizer</td></tr>
+<tr><td>ADO Rating</td><td>black dot</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/silence-time-zones-mw0000595735">AMG Rating</a></td><td>4 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Charles Gayle</td></tr>
+<tr><td>CD</td><td>Time Zones</td></tr>
+<tr><td>Copyright Date</td><td>2006</td></tr>
+<tr><td>Label</td><td>Tompkins Square</td></tr>
+<tr><td>ID</td><td>TSQ2839</td></tr>
+<tr><td>Total Time</td><td>49:06</td></tr>
+<tr><td>Personnel</td><td>Charles Gayle, piano</td></tr>
+<tr><td>ADO Rating</td><td>1 star</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/time-zones-mw0000349642">AMG Rating</a></td><td>4.5 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>The Get Up Kids</td></tr>
+<tr><td>CD</td><td>Eudora</td></tr>
+<tr><td>Copyright Date</td><td>2001</td></tr>
+<tr><td>Label</td><td>Vagrant</td></tr>
+<tr><td>ID</td><td>357</td></tr>
+<tr><td>Total Time</td><td>65:12</td></tr>
+<tr><td>Notes</td><td>Includes the song "Central Standard Time." Thanks to Colin Bowern for this information.</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/eudora-mw0000592063">AMG Rating</a></td><td>2.5 stars</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+
+<tr><td>Artist</td><td>Coldplay</td></tr>
+<tr><td>Song</td><td>Clocks</td></tr>
+<tr><td>Copyright Date</td><td>2003</td></tr>
+<tr><td>Label</td><td>Capitol Records</td></tr>
+<tr><td>ID</td><td>52608</td></tr>
+<tr><td>Total Time</td><td>4:13</td></tr>
+<tr><td>Notes</td><td>Won the 2004 Record of the Year honor at the
+Grammy Awards. Co-written and performed by Chris Martin,
+great-great-grandson of DST inventor William Willett. The song's first
+line is "Lights go out and I can't be saved".</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+
+<tr><td>Artist</td><td>Jaime Guevara</td></tr>
+<tr><td>Song</td><td><a
+href="https://www.youtube.com/watch?v=ZfN4Fe_A50U">Qu&eacute;
+hora es</a></td></tr>
+<tr><td>Date</td><td>1993</td></tr>
+<tr><td>Total Time</td><td>3:04</td></tr>
+<tr><td>Notes</td><td>The song protested "Sixto Hour" in Ecuador
+(1992&ndash;3). Its lyrics include "Amanec&iacute;a en mitad de la noche, los
+guaguas iban a clase sin sol" ("It was dawning in the middle of the
+night, the buses went to class without sun").
+<tr><td>&nbsp;</td><td></td></tr>
+
+<tr><td>Artist</td><td>Irving Kahal and Harry Richman</td></tr>
+<tr><td>Song</td><td>There Ought to be a Moonlight Saving Time</td></tr>
+<tr><td>Copyright Date</td><td>1931</td>
+<tr><td>Notes</td><td>This musical standard was a No. 1 hit for Guy Lombardo
+in 1931, and was also performed by Maurice Chevalier, Blossom Dearie
+and many others. The phrase "Moonlight saving time" also appears in
+the 1995 country song "Not Enough Hours in the Night" written by Aaron
+Barker, Kim Williams and Rob Harbin and performed by Doug
+Supernaw.</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+
+<tr><td>Artist</td><td>The Microscopic Septet</td></tr>
+<tr><td>CD</td><td>Lobster Leaps In</td></tr>
+<tr><td>Copyright Date</td><td>2008</td></tr>
+<tr><td>Label</td><td>Cuneiform</td></tr>
+<tr><td>ID</td><td>272</td></tr>
+<tr><td>Total Time</td><td>73:05</td></tr>
+<tr><td>Notes</td><td>Includes the song "Twilight Time Zone."</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/lobster-leaps-in-mw0000794929">AMG Rating</a></td><td>3.5 stars</td></tr>
+<tr><td>ADO Rating</td><td>2 stars</td></tr>
+
+<tr><td>&nbsp;</td><td></td></tr>
+
+<tr><td>Artist</td><td>Bob Dylan</td></tr>
+<tr><td>CD</td><td>The Times They Are a-Changin'</td></tr>
+<tr><td>Copyright Date</td><td>1964</td></tr>
+<tr><td>Label</td><td>Columbia</td></tr>
+<tr><td>ID</td><td>CK-8905</td></tr>
+<tr><td>Total Time</td><td>45:36</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/the-times-they-a-changin-mw0000202344">AMG Rating</a></td><td>4.5 stars</td></tr>
+<tr><td>ADO Rating</td><td>1.5 stars</td></tr>
+<tr><td>Notes<td>The title song is also available on "Bob Dylan's Greatest Hits" and "The Essential Bob Dylan."</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+
+<tr><td>Artist</td><td>Luciana Souza</td></tr>
+<tr><td>CD</td><td>Tide</td></tr>
+<tr><td>Copyright Date</td><td>2009</td></tr>
+<tr><td>Label</td><td>Universal Jazz France</td></tr>
+<tr><td>ID</td><td>B0012688-02</td></tr>
+<tr><td>Total Time</td><td>42:31</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/tide-mw0000815692">AMG Rating</a></td><td>3.5 stars</td></tr>
+<tr><td>ADO Rating</td><td>2.5 stars</td></tr>
+<tr><td>Notes<td>Includes the song "Fire and Wood" with the lyric
+"The clocks were turned back you remember/Think it's still November."
+</td></tr>
+<tr><td>&nbsp;</td><td></td></tr>
+<tr><td>Artist</td><td>Ken Nordine</td></tr>
+<tr><td>CD</td><td>You're Getting Better: The Word Jazz Dot Masters</td></tr>
+<tr><td>Copyright Date</td><td>2005</td></tr>
+<tr><td>Label</td><td>Geffen</td></tr>
+<tr><td>ID</td><td>B0005171-02</td></tr>
+<tr><td>Total Time</td><td>156:22</td></tr>
+<tr><td>ADO Rating</td><td>1 star</td></tr>
+<tr><td><a href="http://www.allmusic.com/album/youre-getting-better-the-word-jazz-dot-masters-mw0000736197">AMG Rating</a></td><td>4.5 stars</td></tr>
+<tr><td>Notes</td><td>Includes the piece "What Time Is It"
+("He knew what time it was everywhere...that counted").</td></tr>
+</table>
+<h2>Comics</h2>
+<ul>
+<li>
+The webcomic <em>xkcd</em> has the strip
+"<a href='https://xkcd.com/673/'>The Sun</a>" (2009-12-09) and the panels
+"<a href='https://xkcd.com/1017/'>Backward in Time</a>" (2012-02-14),
+"<a href='https://xkcd.com/1061/'>EST</a>" (2012-05-28),
+"<a href='https://xkcd.com/1179/'>ISO 8601</a>" (2013-02-27),
+"<a href='https://xkcd.com/1335/'>Now</a>" (2014-02-26),
+"<a href='https://xkcd.com/1655/'>Doomsday Clock</a>" (2016-03-14),
+"<a href='https://xkcd.com/1799/'>Bad Map Projection: Time Zones</a>"
+(2017-02-15), and
+"<a href='https://xkcd.com/1883/'>Supervillain Plan</a>" (2017-08-30).
+The related book <em>What If?</em> has an entry
+"<a href='https://what-if.xkcd.com/26/'>Leap Seconds</a>" (2012-12-31).
+</li>
+<li>
+Pig kills time in <a
+href="http://www.gocomics.com/pearlsbeforeswine/2016/11/06"><em>Pearls
+Before Swine</em> (2016-11-06)</a>.
+</li>
+<li>
+Stonehenge is abandoned in <a
+href='http://www.gocomics.com/nonsequitur/2017/03/12'><em>Non Sequitur</em>
+(2017-03-12)</a>.
+<li>
+The boss freaks out in <a
+href='http://dilbert.com/strip/1998-03-14'><em>Dilbert</em> (1998-03-14)</a>.
+</li>
+<li>
+Peppermint Patty: "What if the world comes to an end tonight, Marcie?"
+<br>
+Marcie: "I promise there'll be a tomorrow, sir ... in fact,
+it's already tomorrow in Australia!"
+<br>
+(Charles M. Schulz, <a href='http://www.gocomics.com/peanuts/1980/06/13'><em>Peanuts</em>, 1980-06-13</a>)
+</li>
+</ul>
+<h2>Jokes</h2>
+<ul>
+<li>
+The idea behind daylight saving time was first proposed as a joke by
+Benjamin Franklin. To enforce it, he suggested, "Every
+morning, as soon as the sun rises, let all the bells in every church
+be set ringing; and if that is not sufficient, let cannon be fired in
+every street, to wake the sluggards effectually, and make them open
+their eyes to see their true interest. All the difficulty will be in
+the first two or three days: after which the reformation will be as
+natural and easy as the present irregularity; for, <em>ce n'est que le
+premier pas qui co&ucirc;te</em>."
+<a href="http://www.webexhibits.org/daylightsaving/franklin3.html">Franklin's
+joke</a> was first published on 1784-04-26 by the
+<em>Journal de Paris</em> as <a
+href="https://en.wikipedia.org/wiki/File:Franklin-Benjamin-Journal-de-Paris-1784.jpg">an
+anonymous letter translated into French</a>.
+</li>
+<li>
+"We've been using the five-cent nickel in this country since 1492.
+Now that's pretty near 100 years, daylight saving."
+(Groucho Marx as Captain Spaulding in <em>Animal Crackers</em>, 1930,
+as noted by Will Fitzgerald)
+</li>
+<li>
+BRADY. ...[Bishop Usher] determined that the Lord began the Creation
+on the 23rd of October in the Year 4,004 B.C. at &ndash; uh, 9 A.M.!
+<br>
+DRUMMOND. That Eastern Standard Time? (<em>Laughter.</em>) Or Rocky Mountain
+Time? (<em>More laughter.</em>) It wasn't daylight-saving time, was it? Because
+the Lord didn't make the sun until the fourth day!
+<br>
+(From the play <em>Inherit the Wind</em> by Jerome Lawrence and Robert E. Lee,
+filmed in 1960 with Spencer Tracy as Drummond and Fredric March as
+Brady, and several other times. Thanks to Mark Brader.)
+</li>
+<li>
+"Good news."
+"What did they do? Extend Daylight Saving Time year round?"
+(Professional tanner George Hamilton, in dialog from a
+May, 1999 episode of the syndicated television series <em>Baywatch</em>)
+</li>
+<li>
+"A fundamental belief held by Americans is that if you are on land, you
+cannot be killed by a fish...So most Americans remain on land, believing
+they're safe. Unfortunately, this belief &ndash; like so many myths, such as that
+there's a reason for 'Daylight Saving Time' &ndash; is false."
+(Dave Barry column, 2000-07-02)
+</li>
+<li>
+"I once had sex for an hour and five minutes, but that was on the day
+when you turn the clocks ahead."
+(Garry Shandling, 52nd Annual Emmys, 2000-09-10)
+</li>
+<li>
+"Would it impress you if I told you I invented Daylight Savings Time?"
+("Sahjhan" to "Lilah" in dialog from the "Loyalty" episode of <em>Angel</em>,
+originally aired 2002-02-25)
+</li>
+<li>
+"I thought you said Tulsa was a three-hour flight."
+"Well, you're forgetting about the time difference."
+("Joey" and "Chandler" in dialog from the episode of <em>Friends</em>
+entitled "The One With Rachel's Phone Number," originally aired 2002-12-05)
+</li>
+<li>
+"Is that a pertinent fact,
+or are you just trying to dazzle me with your command of time zones?"
+(Kelsey Grammer as "Frasier Crane" to "Roz" from the episode of <em>Frasier</em>
+entitled "The Kid," originally aired 1997-11-04)
+</li>
+<li>
+"I put myself and my staff through this crazy, huge ordeal, all because
+I refused to go on at midnight, okay? And so I work, you know, and
+then I get this job at eleven, supposed to be a big deal. Then
+yesterday daylight [saving] time ended. Right now it's basically
+midnight." (Conan O'Brien on the 2010-11-08 premiere of <em>Conan</em>.)
+</li>
+<li>
+"The best method, I told folks, was to hang a large clock high on a
+barn wall where all the cows could see it. If you have Holsteins, you
+will need to use an analog clock." (Jerry Nelson, <a
+href="http://www.agriculture.com/family/farm-humor/how-to-adjust-dairy-cows-to-daylight-savings-time">How
+to adjust dairy cows to daylight saving time</a>", <em>Successful Farming</em>,
+2017-10-09.)
+</li>
+<li>
+"And now, driving to California, I find that I must enter a password
+in order to change the time zone on my laptop clock. Evidently,
+someone is out to mess up my schedule and my clock must be secured."
+(Garrison Keillor,
+"<a href="http://www.garrisonkeillor.com/weve-never-been-here-before/">We've
+never been here before</a>", 2017-08-22)
+</li>
+<li>
+"Well, in my time zone that's all the time I have,
+but maybe in your time zone I haven't finished yet. So stay tuned!"
+(Goldie Hawn, <em>Rowan &amp; Martin's Laugh-In</em> No. 65, 1970-03-09)
+</li>
+</ul>
+<h2>See also</h2>
+<ul>
+<li><a href="tz-link.html">Sources for Time Zone and Daylight Saving
+Time Data</a></li>
+</ul>
+<hr>
+<address>
+This web page is in the public domain, so clarified as of
+2009-05-17 by Arthur David Olson.
+<br>
+Please send corrections to this web page to the
+<a href="mailto:tz@iana.org">time zone mailing list</a>.
+</address>
+</body>
+</html>
diff --git a/tz-how-to.html b/tz-how-to.html
new file mode 100644
index 000000000000..a54f54a9689e
--- /dev/null
+++ b/tz-how-to.html
@@ -0,0 +1,682 @@
+<!DOCTYPE html
+ PUBLIC "-//W3C//DTD HTML 4.01//EN"
+ "http://www.w3.org/TR/html4/strict.dtd">
+<html>
+<head>
+<title>How to Read the tz Database</title>
+<meta http-equiv="Content-type" content='text/html; charset="UTF-8"'>
+</head>
+<body>
+<h2>How to Read the <a href="https://en.wikipedia.org/wiki/Tz_database">tz
+Database</a> Source Files</h2>
+<h3>by Bill Seymour</h3>
+<p>This page uses the <code>America/Chicago</code> and
+<code>Pacific/Honolulu</code> zones as examples of how to infer
+times of day from the <a href="tz-link.html">tz database</a>
+source files. It might be helpful, but not absolutely necessary,
+for the reader to have already downloaded the
+latest release of the database and become familiar with the basic layout
+of the data files. The format is explained in the &ldquo;man
+page&rdquo; for the zic compiler, <code>zic.8.txt</code>, in
+the <code>code</code> subdirectory.</p>
+
+<p>We&rsquo;ll begin by talking about the rules for changing between standard
+and daylight saving time since we&rsquo;ll need that information when we talk
+about the zones.</p>
+
+<p>First, let&rsquo;s consider the special daylight saving time rules
+for Chicago (from the <code>northamerica</code> file in
+the <code>data</code> subdirectory):</p>
+
+<table border="1">
+<tr>
+ <th colspan="6">From the Source File</th>
+</tr>
+<tr>
+ <td colspan="6" align="center"><table><tr><td>
+<pre>
+#Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
+Rule Chicago 1920 only - Jun 13 2:00 1:00 D
+Rule Chicago 1920 1921 - Oct lastSun 2:00 0 S
+Rule Chicago 1921 only - Mar lastSun 2:00 1:00 D
+Rule Chicago 1922 1966 - Apr lastSun 2:00 1:00 D
+Rule Chicago 1922 1954 - Sep lastSun 2:00 0 S
+Rule Chicago 1955 1966 - Oct lastSun 2:00 0 S
+</pre>
+ </td></tr></table></td>
+</tr>
+<tr>
+ <th colspan="6">Reformatted a Bit</th>
+</tr>
+<tr>
+ <th>From</th>
+ <th>To</th>
+ <th colspan="2">On</th>
+ <th>At</th>
+ <th>Action</th>
+</tr>
+<tr align="center">
+ <td colspan="2">1920 only</td>
+ <td colspan="2">June 13<small><sup>th</sup></small></td>
+ <td rowspan="6">02:00 local</td>
+ <td>go to daylight saving time</td>
+</tr>
+<tr align="center">
+ <td>1920</td>
+ <td>1921</td>
+ <td rowspan="5">last Sunday</td>
+ <td>in October</td>
+ <td>return to standard time</td>
+</tr>
+<tr align="center">
+ <td colspan="2">1921 only</td>
+ <td>in March</td>
+ <td rowspan="2">go to daylight saving time</td>
+</tr>
+<tr align="center">
+ <td rowspan="2">1922</td>
+ <td>1966</td>
+ <td>in April</td>
+</tr>
+<tr align="center">
+ <td>1954</td>
+ <td>in September</td>
+ <td rowspan="2">return to standard time</td>
+</tr>
+<tr align="center">
+ <td>1955</td>
+ <td>1966</td>
+ <td>in October</td>
+</tr>
+</table>
+
+<p>We&rsquo;ll basically just ignore the <code>TYPE</code> column.
+In the 2007j release, the most recent as of this writing, the
+<code>TYPE</code> column never contains anything but a hyphen,
+a kind of null value. (From the description in <code>zic.8.txt</code>,
+this appears to be a mechanism for removing years from a set
+in some localizable way. It&rsquo;s used in the file, <code>pacificnew</code>,
+to determine whether a given year will have a US presidential election;
+but everything related to that use is commented out.)
+
+<p>The <code>SAVE</code> column contains the wall clock offset from
+local standard time.
+This is usually either zero for standard time or one hour for daylight
+saving time; but there&rsquo;s no reason, in principle, why it can&rsquo;t
+take on other values.
+
+<p>The <code>LETTER</code> (sometimes called <code>LETTER/S</code>)
+column can contain a variable
+part of the usual abbreviation of the time zone&rsquo;s name, or it can just
+be a hyphen if there&rsquo;s no variable part. For example, the abbreviation
+used in the central time zone will be either &ldquo;CST&rdquo; or
+&ldquo;CDT&rdquo;. The variable part is &lsquo;S&rsquo; or &lsquo;D&rsquo;;
+and, sure enough, that&rsquo;s just what we find in
+the <code>LETTER</code> column
+in the <code>Chicago</code> rules. More about this when we talk about
+&ldquo;Zone&rdquo; lines.
+
+<p>One important thing to notice is that &ldquo;Rule&rdquo; lines
+want at once to be both <i>transitions</i> and <i>steady states</i>:
+<ul>
+<li>On the one hand, they represent transitions between standard and
+daylight saving time; and any number of Rule lines can be in effect
+during a given period (which will always be a non-empty set of
+contiguous calendar years).</li>
+<li>On the other hand, the <code>SAVE</code> and <code>LETTER</code>
+columns contain state that exists between transitions. More about this
+when we talk about the US rules.</li>
+</ul>
+
+<p>In the example above, the transition to daylight saving time
+happened on the 13<small><sup>th</sup></small> of June in 1920, and on
+the last Sunday in March in 1921; but the return to standard time
+happened on the last Sunday in October in both of those
+years. Similarly, the rule for changing to daylight saving time was
+the same from 1922 to 1966; but the rule for returning to standard
+time changed in 1955. Got it?</p>
+
+<p>OK, now for the somewhat more interesting &ldquo;US&rdquo; rules:</p>
+
+<table border="1">
+<tr>
+ <th colspan="6">From the Source File</th>
+</tr>
+<tr>
+ <td colspan="6" align="center"><table><tr><td>
+<pre>
+#Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
+Rule US 1918 1919 - Mar lastSun 2:00 1:00 D
+Rule US 1918 1919 - Oct lastSun 2:00 0 S
+Rule US 1942 only - Feb 9 2:00 1:00 W # War
+Rule US 1945 only - Aug 14 23:00u 1:00 P # Peace
+Rule US 1945 only - Sep 30 2:00 0 S
+Rule US 1967 2006 - Oct lastSun 2:00 0 S
+Rule US 1967 1973 - Apr lastSun 2:00 1:00 D
+Rule US 1974 only - Jan 6 2:00 1:00 D
+Rule US 1975 only - Feb 23 2:00 1:00 D
+Rule US 1976 1986 - Apr lastSun 2:00 1:00 D
+Rule US 1987 2006 - Apr Sun&gt;=1 2:00 1:00 D
+Rule US 2007 max - Mar Sun&gt;=8 2:00 1:00 D
+Rule US 2007 max - Nov Sun&gt;=1 2:00 0 S
+</pre>
+ </td></tr></table></td>
+</tr>
+<tr>
+ <th colspan="6">Reformatted a Bit</th>
+</tr>
+<tr>
+ <th>From</th>
+ <th>To</th>
+ <th colspan="2">On</th>
+ <th>At</th>
+ <th>Action</th>
+</tr>
+<tr align="center">
+ <td rowspan="2">1918</td>
+ <td rowspan="2">1919</td>
+ <td rowspan="2">last Sunday</td>
+ <td>in March</td>
+ <td rowspan="3">02:00 local</td>
+ <td>go to daylight saving time</td>
+</tr>
+<tr align="center">
+ <td>in October</td>
+ <td>return to standard time</td>
+</tr>
+<tr align="center">
+ <td colspan="2">1942 only</td>
+ <td colspan="2">February 9<small><sup>th</sup></small></td>
+ <td>go to &ldquo;war time&rdquo;</td>
+</tr>
+<tr align="center">
+ <td colspan="2" rowspan="2">1945 only</td>
+ <td colspan="2">August 14<small><sup>th</sup></small></td>
+ <td>23:00 <a href="https://en.wikipedia.org/wiki/Universal_Time">UT</a></td>
+ <td>
+ rename &ldquo;war time&rdquo; to &ldquo;peace<br>time;&rdquo;
+ clocks don&rsquo;t change
+ </td>
+</tr>
+<tr align="center">
+ <td colspan="2">September 30<small><sup>th</sup></small></td>
+ <td rowspan="9">02:00 local</td>
+ <td rowspan="2">return to standard time</td>
+</tr>
+<tr align="center">
+ <td rowspan="2">1967</td>
+ <td>2006</td>
+ <td rowspan="2">last Sunday</td>
+ <td>in October</td>
+</tr>
+<tr align="center">
+ <td>1973</td>
+ <td>in April</td>
+ <td rowspan="6">go to daylight saving time</td>
+</tr>
+<tr align="center">
+ <td colspan="2">1974 only</td>
+ <td colspan="2">January 6<small><sup>th</sup></small></td>
+</tr>
+<tr align="center">
+ <td colspan="2">1975 only</td>
+ <td colspan="2">February 23<small><sup>rd</sup></small></td>
+</tr>
+<tr align="center">
+ <td>1976</td>
+ <td>1986</td>
+ <td>last Sunday</td>
+ <td rowspan="2">in April</td>
+</tr>
+<tr align="center">
+ <td>1987</td>
+ <td>2006</td>
+ <td>first Sunday</td>
+</tr>
+<tr align="center">
+ <td rowspan="2">2007</td>
+ <td rowspan="2">present</td>
+ <td colspan="2">second Sunday in March</td>
+</tr>
+<tr align="center">
+ <td colspan="2">first Sunday in November</td>
+ <td>return to standard time</td>
+</tr>
+</table>
+
+<p>There are two interesting things to note here.</p>
+
+<p>First, the time that something happens (in the <code>AT</code>
+column) is not necessarily the local wall clock time. The time can be
+suffixed with &lsquo;s&rsquo; (for &ldquo;standard&rdquo;) to mean
+local standard time (different from wall clock time when observing
+daylight saving time); or it can be suffixed with &lsquo;g&rsquo;,
+&lsquo;u&rsquo;, or &lsquo;z&rsquo;, all three of which mean the
+standard time at the
+<a href="https://en.wikipedia.org/wiki/Prime_Meridian">prime meridian</a>.
+&lsquo;g&rsquo; stands for &ldquo;<a
+href="https://en.wikipedia.org/wiki/Greenwich_Mean_Time">GMT</a>&rdquo;;
+&lsquo;u&rsquo; stands for &ldquo;<a
+href="https://en.wikipedia.org/wiki/Universal_Time">UT</a>&rdquo; or &ldquo;<a
+href="https://en.wikipedia.org/wiki/Coordinated_Universal_Time">UTC</a>&rdquo;
+(whichever was official at the time); &lsquo;z&rsquo; stands for the
+<a href="https://en.wikipedia.org/wiki/Nautical_time">nautical time zone</a>
+Z (a.k.a. &ldquo;Zulu&rdquo; which, in turn, stands for &lsquo;Z&rsquo;).
+The time can also be suffixed with &lsquo;w&rsquo; meaning &ldquo;wall
+clock time;&rdquo; but it usually isn&rsquo;t because that&rsquo;s the
+default.</p>
+
+<p>Second, the day in the <code>ON</code> column, in addition to
+&ldquo;<code>lastSun</code>&rdquo; or a particular day of the month,
+can have the form, &ldquo;<code>Sun&gt;=</code><i>x</i>&rdquo; or
+&ldquo;<code>Sun&lt;=</code><i>x</i>,&rdquo; where <i>x</i> is a day
+of the month. For example, &ldquo;<code>Sun&gt;=8</code>&rdquo; means
+&ldquo;the first Sunday on or after the eighth of the month,&rdquo; in
+other words, the second Sunday of the month. Furthermore, although
+there are no examples above, the weekday needn&rsquo;t be
+&ldquo;<code>Sun</code>&rdquo; in either form, but can be the usual
+three-character English abbreviation for any day of the week.</p>
+
+<p>And the US rules give us more examples of a couple of things
+already mentioned:</p>
+
+<ul>
+<li>The rules for changing to and from daylight saving time are
+actually <i>different sets</i> of rules; and the two sets can change
+independently. Consider, for example, that the rule for the return to
+standard time stayed the same from 1967 to 2006; but the rule for the
+transition to daylight saving time changed several times in the same
+period. There can also be periods, 1946 to 1966 for example, when no
+rule from this group is in effect, and so either no transition
+happened in those years, or some other rule is in effect (perhaps a
+state or other more local rule).</li>
+
+<li>The <code>SAVE</code> and <code>LETTER</code> columns
+contain <i>steady state</i>, not transitions. Consider, for example,
+the transition from &ldquo;war time&rdquo; to &ldquo;peace time&rdquo;
+that happened on August 14, 1945. The &ldquo;1:00&rdquo; in
+the <code>SAVE</code> column is <i>not</i> an instruction to advance
+the clock an hour. It means that clocks should <i>be</i> one hour
+ahead of standard time, which they already are because of the previous
+rule, so there should be no change.</li>
+
+</ul>
+
+<p>OK, now let&rsquo;s look at a Zone record:</p>
+
+<table border="1">
+<tr>
+ <th colspan="5">From the Source File</th>
+</tr>
+<tr>
+ <td colspan="6" align="center"><table><tr><td>
+<pre>
+#Zone NAME GMTOFF RULES FORMAT [UNTIL]
+Zone America/Chicago -5:50:36 - LMT 1883 Nov 18 12:09:24
+ -6:00 US C%sT 1920
+ -6:00 Chicago C%sT 1936 Mar 1 2:00
+ -5:00 - EST 1936 Nov 15 2:00
+ -6:00 Chicago C%sT 1942
+ -6:00 US C%sT 1946
+ -6:00 Chicago C%sT 1967
+ -6:00 US C%sT
+</pre>
+ </td></tr></table></td>
+</tr>
+<tr>
+ <th colspan="5">Columns Renamed</th>
+</tr>
+<tr>
+ <th rowspan="2">Standard Offset<br>
+ from <a href="https://en.wikipedia.org/wiki/Prime_Meridian">Prime
+ Meridian</a></th>
+ <th rowspan="2">Daylight<br>Saving Time</th>
+ <th rowspan="2">Abbreviation(s)</th>
+ <th colspan="2">Ending at Local Time</th>
+</tr>
+<tr>
+ <th>Date</th>
+ <th>Time</th>
+</tr>
+<tr align="center">
+ <td>&minus;5:50:36</td>
+ <td>not observed</td>
+ <td>LMT</td>
+ <td>1883-11-18</td>
+ <td>12:09:24</td>
+</tr>
+<tr align="center">
+ <td rowspan="2">&minus;6:00:00</td>
+ <td>US rules</td>
+ <td rowspan="2">CST or CDT</td>
+ <td>1920-01-01</td>
+ <td>00:00:00</td>
+</tr>
+<tr align="center">
+ <td>Chicago rules</td>
+ <td>1936-03-01</td>
+ <td rowspan="2">02:00:00</td>
+</tr>
+<tr align="center">
+ <td>&minus;5:00:00</td>
+ <td>not observed</td>
+ <td>EST</td>
+ <td>1936-11-15</td>
+</tr>
+<tr align="center">
+ <td rowspan="4">&minus;6:00:00</td>
+ <td>Chicago rules</td>
+ <td>CST or CDT</td>
+ <td>1942-01-01</td>
+ <td rowspan="3">00:00:00</td>
+</tr>
+<tr align="center">
+ <td>US rules</td>
+ <td>CST, CWT or CPT</td>
+ <td>1946-01-01</td>
+</tr>
+<tr align="center">
+ <td>Chicago rules</td>
+ <td rowspan="2">CST or CDT</td>
+ <td>1967-01-01</td>
+</tr>
+<tr align="center">
+ <td>US rules</td>
+ <td colspan="2">&mdash;</td>
+</tr>
+</table>
+
+<p>There are a couple of interesting differences between Zones and Rules.</p>
+
+<p>First, and somewhat trivially, whereas Rules are considered to
+contain one or more records, a Zone is considered to be a single
+record with zero or more <i>continuation lines</i>. Thus, the keyword,
+&ldquo;<code>Zone</code>,&rdquo; and the zone name are not
+repeated. The last line is the one without anything in
+the <code>[UNTIL]</code> column.</p>
+
+<p>Second, and more fundamentally, each line of a Zone represents a
+steady state, not a transition between states. The state exists from
+the date and time in the previous line&rsquo;s <code>[UNTIL]</code>
+column up to the date and time in the current
+line&rsquo;s <code>[UNTIL]</code> column. In other words, the date and
+time in the <code>[UNTIL]</code> column is the instant that separates
+this state from the next. Where that would be ambiguous because
+we&rsquo;re setting our clocks back, the <code>[UNTIL]</code> column
+specifies the first occurrence of the instant. The state specified by
+the last line, the one without anything in the <code>[UNTIL]</code>
+column, continues to the present.</p>
+
+<p>The first line typically specifies the mean solar time observed
+before the introduction of standard time. Since there&rsquo;s no line before
+that, it has no beginning. <code>8-) </code> For some places near the <a
+href="https://en.wikipedia.org/wiki/International_Date_Line">International
+Date Line</a>, the first <i>two</i> lines will show solar times
+differing by 24 hours; this corresponds to a movement of the Date
+Line. For example:</p>
+
+<pre>
+#Zone NAME GMTOFF RULES FORMAT [UNTIL]
+Zone America/Juneau 15:02:19 - LMT 1867 Oct 18
+ -8:57:41 - LMT ...
+</pre>
+
+<p>When Alaska was purchased from Russia in 1867, the Date Line moved
+from the Alaska/Canada border to the Bering Strait; and the time in
+Alaska was then 24 hours earlier than it had
+been. <code>&lt;aside&gt;</code>(6 October in the Julian calendar,
+which Russia was still using then for religious reasons, was followed
+by <i>a second instance of the same day with a different name</i>, 18
+October in the Gregorian calendar. Isn&rsquo;t civil time
+wonderful? <code>8-)</code>)<code>&lt;/aside&gt;</code></p>
+
+<p>The abbreviation, &ldquo;LMT&rdquo; stands for &ldquo;local mean
+time&rdquo;, which is an invention of
+the <a href="https://en.wikipedia.org/wiki/Tz_database">tz
+database</a> and was probably never actually used during the
+period. Furthermore, the value is almost certainly wrong except in the
+archetypal place after which the zone is named. (The tz database
+usually doesn&rsquo;t provide a separate Zone record for places where
+nothing significant happened after 1970.)</p>
+
+<p>The <code>RULES</code> column tells us whether daylight saving time is being observed:
+<ul>
+<li>A hyphen, a kind of null value, means that we have not set our
+clocks ahead of standard time.</li>
+
+<li>An amount of time (usually but not necessarily &ldquo;1:00&rdquo;
+meaning one hour) means that we have set our clocks ahead by that
+amount.</li>
+
+<li>Some alphabetic string means that we <i>might have</i> set our
+clocks ahead; and we need to check the rule the name of which is the
+given alphabetic string.</li>
+</ul>
+
+<p>An example of a specific amount of time is:</p>
+<pre>
+#Zone NAME GMTOFF RULES FORMAT [UNTIL]
+Zone Pacific/Honolulu ... 1933 Apr 30 2:00
+ -10:30 1:00 HDT 1933 May 21 2:00
+ ...
+</pre>
+
+<p>Hawaii tried daylight saving time for three weeks in 1933 and
+decided they didn&rsquo;t like it. <code>8-) </code>Note that
+the <code>GMTOFF</code> column always contains the standard time
+offset, so the wall clock time during this period was GMT &minus;
+10:30 + 1:00 = GMT &minus; 9:30.</p>
+
+<p>The <code>FORMAT</code> column specifies the usual abbreviation of
+the time zone name. It can have one of three forms:</p>
+<ul>
+
+<li>a string of three or more characters that are either ASCII alphanumerics,
+&ldquo;<code>+</code>&rdquo;, or &ldquo;<code>-</code>&rdquo;,
+in which case that&rsquo;s the abbreviation</li>
+
+<li>a pair of strings separated by a slash
+(&lsquo;<code>/</code>&rsquo;), in which case the first string is the
+abbreviation for the standard time name and the second string is the
+abbreviation for the daylight saving time name</li>
+
+<li>a string containing &ldquo;<code>%s</code>,&rdquo; in which case
+the &ldquo;<code>%s</code>&rdquo; will be replaced by the text in the
+appropriate Rule&rsquo;s <code>LETTER</code> column</li>
+</ul>
+
+<p>The last two make sense only if there&rsquo;s a named rule in effect.</p>
+
+<p>An example of a slash is:</p>
+<pre>
+#Zone NAME GMTOFF RULES FORMAT [UNTIL]
+Zone Europe/London ... 1996
+ 0:00 EU GMT/BST
+</pre>
+
+<p>The current time in the UK is called either Greenwich mean time or
+British summer time.</p>
+
+<p>One wrinkle, not fully explained in <code>zic.8.txt</code>, is what
+happens when switching to a named rule. To what values should
+the <code>SAVE</code> and <code>LETTER</code> data be initialized?</p>
+
+<ul>
+<li>If at least one transition has happened, use
+the <code>SAVE</code> and <code>LETTER</code> data from the most
+recent.</li>
+
+<li>If switching to a named rule before any transition has happened,
+assume standard time (<code>SAVE</code> zero), and use
+the <code>LETTER</code> data from the earliest transition with
+a <code>SAVE</code> of zero.
+
+</ul>
+
+<p>And three last things about the <code>FORMAT</code> column:</p>
+<ul>
+
+<li>The <a href="https://en.wikipedia.org/wiki/Tz_database">tz
+database</a> gives abbreviations for time zone names in <i>popular
+usage</i>, which is not necessarily &ldquo;correct&rdquo; by law. For
+example, the last line in
+<code>Zone</code> <code>Pacific/Honolulu</code> (shown below) gives
+&ldquo;HST&rdquo; for &ldquo;Hawaii standard time&rdquo; even though the
+<a href="https://www.law.cornell.edu/uscode/text/15/263">legal</a>
+name for that time zone is &ldquo;Hawaii-Aleutian standard time.&rdquo;
+This author has read that there are also some places in Australia where
+popular time zone names differ from the legal ones.
+
+<li>No attempt is made to <a
+href="https://en.wikipedia.org/wiki/Internationalization_and_localization">localize</a>
+the abbreviations. They are intended to be the values returned through the
+<code>"%Z"</code> format specifier to
+<a href="https://en.wikipedia.org/wiki/C_(programming_language)">C</a>&rsquo;s
+<a href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/strftime.html"><code>strftime</code></a>
+function in the
+<a href="http://kirste.userpage.fu-berlin.de/chemnet/use/info/libc/libc_19.html#SEC324">&ldquo;C&rdquo; locale</a>.
+
+<li>If there is no generally-accepted abbreviation for a time zone,
+a numeric offset is used instead, e.g., <code>+07</code> for 7 hours
+ahead of Greenwich. By convention, <code>-00</code> is used in a
+zone while uninhabited, where the offset is zero but in some sense
+the true offset is undefined.
+</ul>
+
+<p>As a final example, here&rsquo;s the complete history for Hawaii:</p>
+
+<table border="1">
+<tr>
+ <th colspan="6">Relevant Excerpts from the US Rules</th>
+</tr>
+<tr>
+ <td colspan="6" align="center"><table><tr><td>
+<pre>
+#Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
+Rule US 1918 1919 - Oct lastSun 2:00 0 S
+Rule US 1942 only - Feb 9 2:00 1:00 W # War
+Rule US 1945 only - Aug 14 23:00u 1:00 P # Peace
+Rule US 1945 only - Sep 30 2:00 0 S
+</pre>
+ </td></tr></table></td>
+</tr>
+<tr>
+ <th colspan="6">The Zone Record</th>
+</tr>
+<tr>
+ <td colspan="6" align="center"><table><tr><td>
+<pre>
+#Zone NAME GMTOFF RULES FORMAT [UNTIL]
+Zone Pacific/Honolulu -10:31:26 - LMT 1900 Jan 1 12:00
+ -10:30 - HST 1933 Apr 30 2:00
+ -10:30 1:00 HDT 1933 May 21 2:00
+ -10:30 US H%sT 1947 Jun 8 2:00
+ -10:00 - HST
+</pre>
+ </td></tr></table></td>
+</tr>
+<tr>
+ <th colspan="6">What We Infer</th>
+</tr>
+<tr>
+ <th rowspan="2">Wall-Clock<br>Offset from<br>Prime Meridian</th>
+ <th rowspan="2">Adjust<br>Clocks</th>
+ <th colspan="2">Time Zone</th>
+ <th colspan="2">Ending at Local Time</th>
+</tr>
+<tr>
+ <th>Abbrv.</th>
+ <th>Name</th>
+ <th>Date</th>
+ <th>Time</th>
+</tr>
+<tr align="center">
+ <td>&minus;10:31:26</td>
+ <td>&mdash;</td>
+ <td>LMT</td>
+ <td>local mean time</td>
+ <td>1900-01-01</td>
+ <td>12:00</td>
+</tr>
+<tr align="center">
+ <td>&minus;10:30</td>
+ <td>+0:01:26</td>
+ <td>HST</td>
+ <td>Hawaii standard time</td>
+ <td>1933-04-30</td>
+ <td rowspan="3">02:00</td>
+</tr>
+<tr align="center">
+ <td>&minus;9:30</td>
+ <td>+1:00</td>
+ <td>HDT</td>
+ <td>Hawaii daylight time</td>
+ <td>1933-05-21</td>
+</tr>
+<tr align="center">
+ <td>&minus;10:30&sup1;</td>
+ <td>&minus;1:00&sup1;</td>
+ <td>HST&sup1;</td>
+ <td>Hawaii standard time</td>
+ <td>1942-02-09</td>
+</tr>
+<tr align="center">
+ <td rowspan="2">&minus;9:30</td>
+ <td>+1:00</td>
+ <td>HWT</td>
+ <td>Hawaii war time</td>
+ <td>1945-08-14</td>
+ <td>13:30&sup2;</td>
+</tr>
+<tr align="center">
+ <td>0</td>
+ <td>HPT</td>
+ <td>Hawaii peace time</td>
+ <td>1945-09-30</td>
+ <td rowspan="2">02:00</td>
+</tr>
+<tr align="center">
+ <td>&minus;10:30</td>
+ <td>&minus;1:00</td>
+ <td rowspan="2">HST</td>
+ <td rowspan="2">Hawaii standard time</td>
+ <td>1947-06-08</td>
+</tr>
+<tr align="center">
+ <td>&minus;10:00&sup3;</td>
+ <td>+0:30&sup3;</td>
+ <td colspan="2">&mdash;</td>
+</tr>
+<tr>
+ <td colspan="6">
+ &sup1;Switching to US rules&hellip;most recent transition (in 1919) was to standard time
+ </td>
+</tr>
+<tr>
+ <td colspan="6">
+ &sup2;23:00 <a href="https://en.wikipedia.org/wiki/Universal_Time">UT</a>
+ + (&minus;9:30) = 13:30 local
+ </td>
+</tr>
+<tr>
+ <td colspan="6">
+ &sup3;Since <a href="https://en.wikipedia.org/wiki/ISO_8601">1947&ndash;06&ndash;08T12:30Z</a>,
+ the civil time in Hawaii has been
+ <a href="https://en.wikipedia.org/wiki/Universal_Time">UT</a>/<a href="https://en.wikipedia.org/wiki/Coordinated_Universal_Time">UTC</a>
+ &minus; 10:00 year-round.
+ </td>
+</tr>
+</table>
+
+<p>There will be a short quiz later. <code>8-)</code></p>
+
+<hr>
+<address>
+This web page is in the public domain, so clarified as of
+2015-10-20 by Bill Seymour.
+<br>
+All suggestions and corrections will be welcome; all flames will be amusing.
+Mail to was at pobox dot com.
+</address>
+</body>
+</html>
diff --git a/tz-link.html b/tz-link.html
new file mode 100644
index 000000000000..13a824d7e9af
--- /dev/null
+++ b/tz-link.html
@@ -0,0 +1,953 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<title>Sources for time zone and daylight saving time data</title>
+<meta charset="UTF-8">
+</head>
+<body>
+<h1>Sources for time zone and daylight saving time data</h1>
+<p>
+<a href="https://en.wikipedia.org/wiki/Time_zone">Time zone</a> and
+<a href="https://en.wikipedia.org/wiki/Daylight_saving_time">daylight-saving</a>
+rules are controlled by individual
+governments. They are sometimes changed with little notice, and their
+histories and planned futures are often recorded only fitfully. Here
+is a summary of attempts to organize and record relevant data in this
+area.
+</p>
+<h2 id="tzdb">The <code><abbr title="time zone">tz</abbr></code> database</h2>
+<p>
+The <a href="https://en.wikipedia.org/wiki/Public_domain">public-domain</a>
+time zone database contains code and data
+that represent the history of local time
+for many representative locations around the globe.
+It is updated periodically to reflect changes made by political bodies
+to time zone boundaries and daylight saving rules.
+This database (known as <code><abbr>tz</abbr></code>,
+<code><abbr>tzdb</abbr></code>, or <code>zoneinfo</code>)
+is used by several implementations,
+including
+<a href="https://www.gnu.org/software/libc/">the
+<abbr title="GNU's Not Unix">GNU</abbr>
+C Library</a> (used in
+<a href="https://en.wikipedia.org/wiki/Linux"><abbr>GNU</abbr>/Linux</a>),
+<a href="https://www.android.com">Android</a>,
+<a href="https://developer.mozilla.org/en-US/docs/Mozilla/B2G_OS">B2G
+<abbr title="Operating System">OS</abbr></a>,
+<a href="https://www.freebsd.org">Free<abbr
+title="Berkeley Software Distribution">BSD</abbr></a>,
+<a href="https://netbsd.org">Net<abbr>BSD</abbr></a>,
+<a href="https://www.openbsd.org">Open<abbr>BSD</abbr></a>,
+<a href="https://www.chromium.org/chromium-os">Chromium OS</a>,
+<a href="https://cygwin.com">Cygwin</a>,
+<a href="http://www.delorie.com/djgpp/"><abbr
+title="DJ's GNU Programming Platform">DJGPP</abbr></a>,
+<a href="https://en.wikipedia.org/wiki/MINIX">MINIX</a>,
+<a href="https://www.mysql.com">MySQL</a>,
+<a href="https://en.wikipedia.org/wiki/WebOS"><abbr
+title="Web Operating System">webOS</abbr></a>,
+<a href="https://ibm.com/aix"><abbr
+title="Advanced Interactive eXecutive">AIX</abbr></a>,
+<a href="https://en.wikipedia.org/wiki/BlackBerry_10">BlackBerry 10</a>,
+<a href="https://www.apple.com/ios/"><abbr
+title="iPhone OS">iOS</abbr></a>,
+<a href="https://www.apple.com/macos/">macOS</a>,
+<a href="https://www.microsoft.com/en-us/windows">Microsoft Windows</a>,
+<a href="https://www.hpe.com/info/openvms">Open<abbr
+title="Virtual Memory System">VMS</abbr></a>,
+<a href="https://www.oracle.com/database/index.html">Oracle Database</a>, and
+<a href="https://www.oracle.com/solaris">Oracle Solaris</a>.</p>
+<p>
+Each location in the database represents a region where all
+clocks keeping local time have agreed since 1970.
+Locations are identified by continent or ocean and then by the name of
+the location, which is typically the largest city within the region.
+For example, <code>America/New_York</code>
+represents most of the <abbr title="United States">US</abbr> eastern time zone;
+<code>America/Phoenix</code> represents most of Arizona, which
+uses mountain time without daylight saving time (<abbr
+title="daylight saving time">DST</abbr>);
+<code>America/Detroit</code> represents most of Michigan, which uses
+eastern time but with different <abbr>DST</abbr> rules in 1975;
+and other entries represent smaller regions like Starke County,
+Indiana, which switched from central to eastern time in 1991
+and switched back in 2006.
+To use the database on an extended <a
+href="https://en.wikipedia.org/wiki/POSIX"><abbr
+title="Portable Operating System Interface">POSIX</abbr></a>
+implementation set the <code><abbr>TZ</abbr></code>
+environment variable to the location's full name,
+e.g., <code><abbr>TZ</abbr>="America/New_York"</code>.</p>
+<p>
+Associated with each region is a history of offsets from
+<a href="https://en.wikipedia.org/wiki/Universal_Time">Universal
+Time</a> (<abbr>UT</abbr>), which is <a
+href="https://en.wikipedia.org/wiki/Greenwich_Mean_Time">Greenwich Mean
+Time</a> (<abbr>GMT</abbr>) with days beginning at midnight;
+for time stamps after 1960 this is more precisely <a
+href="https://en.wikipedia.org/wiki/Coordinated_Universal_Time">Coordinated
+Universal Time</a> (<abbr>UTC</abbr>).
+The database also records when daylight saving time was in use,
+along with some time zone abbreviations such as <abbr>EST</abbr>
+for Eastern Standard Time in the <abbr>US</abbr>.</p>
+<h2 id="download">Downloading the <code><abbr>tz</abbr></code> database</h2>
+<p>
+The following <a
+href="https://en.wikipedia.org/wiki/Unix_shell">shell</a> commands download
+the latest release's two
+<a href="https://en.wikipedia.org/wiki/Tar_(computing)">tarballs</a>
+to a <abbr>GNU</abbr>/Linux or similar host.</p>
+<pre style="margin-left: 2em"><code>mkdir tzdb
+cd tzdb
+<a href="https://www.gnu.org/software/wget/">wget</a> https://www.iana.org/time-zones/repository/tzcode-latest.tar.gz
+wget https://www.iana.org/time-zones/repository/tzdata-latest.tar.gz
+<a href="https://www.gnu.org/software/gzip/">gzip</a> -dc tzcode-latest.tar.gz | <a href="https://www.gnu.org/software/tar/">tar</a> -xf -
+gzip -dc tzdata-latest.tar.gz | tar -xf -
+</code></pre>
+<p>Alternatively, the following shell commands download the same
+release in a single-tarball format containing extra data
+useful for regression testing:</p>
+<pre style="margin-left: 2em"><code>wget <a href="https://www.iana.org/time-zones/repository/tzdb-latest.tar.lz">https://www.iana.org/time-zones/repository/tzdb-latest.tar.lz</a>
+<a href="https://www.nongnu.org/lzip/">lzip</a> -dc tzdb-latest.tar.lz | tar -xf -
+</code></pre>
+<p>These commands use convenience links to the latest release
+of the <code><abbr>tz</abbr></code> database hosted by the
+<a href="https://www.iana.org/time-zones">Time Zone Database website</a>
+of the <a href="https://www.iana.org">Internet Assigned Numbers
+Authority (IANA)</a>.
+Older releases are in files named
+<code>tzcode<var>V</var>.tar.gz</code>,
+<code>tzdata<var>V</var>.tar.gz</code>, and
+<code>tzdb-<var>V</var>.tar.lz</code>,
+where <code><var>V</var></code> is the version.
+Since 1996, each version has been a four-digit year followed by
+lower-case letter (<samp>a</samp> through <samp>z</samp>,
+then <samp>za</samp> through <samp>zz</samp>, then <samp>zza</samp>
+through <samp>zzz</samp>, and so on).
+Since version 2016h, each release has contained a text file named
+"<samp>version</samp>" whose first (and currently only) line is the version.
+The releases are also available in an
+<a href="ftp://ftp.iana.org/tz/releases/"><abbr
+title="File Transfer Protocol">FTP</abbr> directory</a> via a
+less-secure protocol.</p>
+<p>Alternatively, a development repository of code and data can be
+retrieved from <a href="https://github.com">GitHub</a> via the shell
+command:</p>
+<pre style="margin-left: 2em"><code><a href="https://git-scm.com">git</a> clone <a href="https://github.com/eggert/tz">https://github.com/eggert/tz</a>
+</code></pre>
+<p>
+Since version 2012e, each release has been tagged in development repositories.
+Untagged commits are less well tested and probably contain
+more errors.</p>
+<p>
+After obtaining the code and data files, see the
+<code>README</code> file for what to do next.
+The code lets you compile the <code><abbr>tz</abbr></code> source files into
+machine-readable binary files, one for each location. It also lets
+you read a <code><abbr>tz</abbr></code> binary file and interpret time stamps for that
+location.</p>
+<h2 id="changes">Changes to the <code><abbr>tz</abbr></code> database</h2>
+<p>
+The <code><abbr>tz</abbr></code> code and data
+are by no means authoritative. If you find errors, please
+send changes to <a href="mailto:tz@iana.org"><code>tz@iana.org</code></a>,
+the time zone mailing list. You can also <a
+href="https://mm.icann.org/mailman/listinfo/tz">subscribe</a> to it
+and browse the <a
+href="https://mm.icann.org/pipermail/tz/">archive of old
+messages</a>.</p>
+<p>
+If your government plans to change its time zone boundaries or
+daylight saving rules, inform <code>tz@iana.org</code> well in
+advance, as this will coordinate updates to many cell phones,
+computers, and other devices around the world. With
+less than a year's notice there is a good chance that some
+computer-based clocks will operate incorrectly after the change, due
+to delays in propagating updates to software and data. The shorter
+the notice, the more likely clock problems will arise; see "<a
+href="https://codeofmatt.com/2016/04/23/on-the-timing-of-time-zone-changes/">On
+the Timing of Time Zone Changes</a>" for examples.
+</p>
+<p>
+Changes to the <code><abbr>tz</abbr></code> code and data are often
+propagated to clients via operating system updates, so
+client <code><abbr>tz</abbr></code> data can often be corrected by
+applying these updates. With GNU/Linux and similar systems, if your
+maintenance provider has not yet adopted the
+latest <code><abbr>tz</abbr></code> data, you can often short-circuit
+the process by tailoring the generic instructions in
+the <code><abbr>tz</abbr> README</code> file and installing the latest
+data yourself. System-specific instructions for installing the
+latest <code><abbr>tz</abbr></code> data have also been published
+for <a href="https://www.ibm.com/developerworks/aix/library/au-aix-olson-time-zone/index.html"><abbr>AIX</abbr></a>,
+<a
+href="https://play.google.com/store/apps/details?id=com.google.android.timezone.data">Android</a>,
+<a
+href="http://userguide.icu-project.org/datetime/timezone"><abbr
+title="International Components for Unicode">ICU</abbr></a>,
+<a href="https://developer.ibm.com/javasdk/support/dst/jtzu/"><abbr>IBM</abbr></a>
+and <a
+href="http://www.oracle.com/technetwork/java/javase/tzupdater-readme-136440.html">Oracle</a>
+Java, <a href="http://www.joda.org/joda-time/tz_update.html">Joda-Time</a>, <a
+href="https://dev.mysql.com/doc/refman/en/time-zone-support.html">MySQL</a>,
+and <a
+href="https://nodatime.org/userguide/tzdb">Noda Time</a> (see below).
+</p>
+<p>Sources for the <code><abbr>tz</abbr></code> database are
+<a href="https://en.wikipedia.org/wiki/UTF-8"><abbr
+title="Unicode Transformation Format 8-bit">UTF-8</abbr></a>
+<a href="https://en.wikipedia.org/wiki/Text_file">text files</a>
+with lines terminated by <a href="https://en.wikipedia.org/wiki/Newline"><abbr
+title="linefeed">LF</abbr></a>,
+which can be modified by common text editors such
+as <a href="https://www.gnu.org/software/emacs/">GNU Emacs</a>,
+<a href="https://wiki.gnome.org/Apps/Gedit">gedit</a>, and
+<a href="https://www.vim.org">vim</a>.
+Specialized source-file editing can be done via the
+<a href="https://packagecontrol.io/packages/zoneinfo">Sublime
+zoneinfo</a> package for <a
+href="https://www.sublimetext.com">Sublime Text</a> and the <a
+href="https://marketplace.visualstudio.com/items?itemName=gilmoreorless.vscode-zoneinfo">VSCode
+zoneinfo</a> extension for <a href="https://code.visualstudio.com">Visual
+Studio Code</a>.
+</p>
+<p>
+For further information about updates, please see
+<a href="https://tools.ietf.org/html/rfc6557">Procedures for
+Maintaining the Time Zone Database</a> (Internet <abbr
+title="Request For Comments">RFC</abbr> 6557). More detail can be
+found in <a href="theory.html">Theory and pragmatics of the tz code and data</a>.
+</p>
+<h2 id="commentary">Commentary on the <code><abbr>tz</abbr></code> database</h2>
+<ul>
+<li>The article
+<a href="https://en.wikipedia.org/wiki/Tz_database">tz database</a> is
+an encyclopedic summary.</li>
+<li><a href="tz-how-to.html">How to Read the
+tz Database Source Files</a> explains the <code><abbr>tz</abbr></code>
+database format.</li>
+<li><a
+href="https://blog.jonudell.net/2009/10/23/a-literary-appreciation-of-the-olsonzoneinfotz-database/">A
+literary appreciation of the Olson/Zoneinfo/tz database</a> comments on the
+database's style.</li>
+</ul>
+<h2 id="web">Web sites using recent versions of the
+<code><abbr>tz</abbr></code> database</h2>
+<p>
+These are listed roughly in ascending order of complexity and fanciness.
+</p>
+<ul>
+<li><a href="https://time.is">Time.is</a> shows locations'
+time and zones.</li>
+<li><a href="https://www.timejones.com">TimeJones.com</a>,
+<a href="https://timezoneconverterapp.com">Time Zone Converter</a> and
+<a href="http://worldclock.com">The World Clock</a>
+are time zone converters.</li>
+<li><a
+href="http://twiki.org/cgi-bin/xtra/tzdatepick.html">Date and Time Gateway</a>
+lets you see the <code><abbr>TZ</abbr></code> values directly.</li>
+<li><a
+href="http://www.convertit.com/Go/ConvertIt/World_Time/Current_Time.ASP">Current
+Time in 1000 Places</a> uses descriptions of the values.</li>
+<li><a href="http://www.timezoneconverter.com/cgi-bin/tzc.tzc">Time Zone
+Converter</a>
+uses a pulldown menu.</li>
+<li><a href="http://home.kpn.nl/vanadovv/time/TZworld.html">Complete
+timezone information for all countries</a> displays tables of DST rules.
+<li><a href="https://www.timeanddate.com/worldclock/">The World Clock &ndash;
+Worldwide</a> lets you sort zone names and convert times.</li>
+<li><a href="https://24timezones.com">24TimeZones</a> has a world
+time map and a time converter.</li>
+<li><a href="https://www.zeitverschiebung.net/en/">Time Difference</a>
+calculates the current time difference between locations.</li>
+<li><a href="http://www.wx-now.com">Weather Now</a> and
+<a href="http://www.thetimenow.com">The Time Now</a> list the weather too.</li>
+</ul>
+<h2 id="protocols">Network protocols for <code><abbr>tz</abbr></code> data</h2>
+<ul>
+<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://tools.ietf.org/html/rfc7808">TZDIST</a>
+(Internet <abbr>RFC</abbr> 7808), a time zone data distribution service,
+along with <a href="https://tools.ietf.org/html/rfc7809">CalDAV</a>
+(Internet <abbr>RFC</abbr> 7809), a calendar access protocol for
+transferring time zone data by reference. The draft <a
+id="TZDIST-Geolocate"
+href="https://tools.ietf.org/html/draft-murchison-tzdist-geolocate-01">TZDIST
+Geolocate Extension</a> lets a client determine its time zone region
+from its geographic location using a <a
+href="https://tools.ietf.org/html/rfc5870">'geo' URI</a>.</li>
+<li>The <a href="https://tools.ietf.org/html/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://tools.ietf.org/html/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://tools.ietf.org/html/rfc7265">jCal</a>
+(Internet <abbr>RFC</abbr> 7265)
+uses <a href="https://www.json.org"><abbr
+title="JavaScript Object Notation">JSON</abbr></a> format.</li>
+</ul>
+<h2 id="compilers">Other <code><abbr>tz</abbr></code> compilers</h2>
+<ul>
+<li><a href="https://sourceforge.net/projects/vzic/">Vzic</a> is a <a
+href="https://en.wikipedia.org/wiki/C_%28programming_language%29">C</a>
+program that compiles
+<code><abbr>tz</abbr></code> source into iCalendar-compatible VTIMEZONE files.
+Vzic is freely
+available under the <a
+href="https://www.gnu.org/copyleft/gpl.html"><abbr>GNU</abbr>
+General Public License (<abbr
+title="General Public License">GPL</abbr>)</a>.</li>
+<li><a href="https://sourceforge.net/projects/tzical/">tziCal &ndash; tz
+database conversion utility</a> is like Vzic, except for the <a
+href="https://www.microsoft.com/net">.NET framework</a>
+and with a <abbr>BSD</abbr>-style license.</li>
+<li><a
+href="http://search.cpan.org/dist/DateTime-TimeZone/">DateTime::TimeZone</a>
+contains a script <code>parse_olson</code> that compiles
+<code><abbr>tz</abbr></code> source into <a href="https://www.perl.org">Perl</a>
+modules. It is part of the Perl <a
+href="http://datetime.perl.org">DateTime Project</a>, which is freely
+available under both the <abbr>GPL</abbr> and the Perl Artistic
+License. DateTime::TimeZone also contains a script
+<code>tests_from_zdump</code> that generates test cases for each clock
+transition in the <code><abbr>tz</abbr></code> database.</li>
+<li>The <a href="https://howardhinnant.github.io/date/tz.html">Time Zone
+Database Parser</a> is a
+<a href="https://en.wikipedia.org/wiki/C%2B%2B">C++</a> parser and
+runtime library that is <a
+href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0355r4.html">moving
+forward</a> for inclusion in the next iteration of <a
+href="https://isocpp.org/std/the-standard"><em><abbr
+title="International Organization for Standardization">ISO</abbr>
+International Standard ISO/IEC 14882:2017(E) &ndash; Programming
+Language C++</em></a>.
+It is freely available under the
+<abbr title="Massachusetts Institute of Technology">MIT</abbr> license.</li>
+<li><a id="ICU" href="http://site.icu-project.org">International Components for
+Unicode (<abbr>ICU</abbr>)</a> contains C/C++ and <a
+href="https://en.wikipedia.org/wiki/Java_%28programming_language%29">Java</a>
+libraries for internationalization that
+has a compiler from <code><abbr>tz</abbr></code> source
+and from <abbr title="Common Locale Data Repository">CLDR</abbr> data
+(mentioned <a href="#CLDR">below</a>)
+into an <abbr>ICU</abbr>-specific format.
+<abbr>ICU</abbr> is freely available under a
+<abbr>BSD</abbr>-style license.</li>
+<li>The <a href="https://github.com/lau/tzdata">Tzdata</a> package for
+the <a href="https://elixir-lang.org">Elixir</a> language downloads
+and compiles tz source and exposes <abbr
+title="Application Program Interface">API</abbr>s for use. It is
+freely available under the <abbr>MIT</abbr> license.</li>
+<li>Java-based compilers and libraries include:
+<ul>
+<li>The <a
+href="http://www.oracle.com/technetwork/java/javase/tzupdater-readme-136440.html">TZUpdater
+tool</a> compiles <code><abbr>tz</abbr></code> source into the format used by
+Oracle Java.</li>
+<li>The <a
+href="http://www.oracle.com/technetwork/articles/java/jf14-date-time-2125367.html">Java
+8 <code>java.time</code> <abbr>API</abbr></a> can be supplemented by <a
+href="http://www.threeten.org/threeten-extra/">ThreeTen-Extra</a>,
+which is freely available under a <abbr>BSD</abbr>-style license.</li>
+<li><a href="http://www.joda.org/joda-time/">Joda-Time &ndash; Java date
+and time <abbr>API</abbr></a> contains a class
+<code>org.joda.time.tz.ZoneInfoCompiler</code> that compiles
+<code><abbr>tz</abbr></code> source into a binary format. It inspired
+Java 8 <code>java.time</code>, which its users should migrate to once
+they can assume Java 8 or later. It is available under the <a
+href="https://www.apache.org/licenses/LICENSE-2.0">Apache License</a>.</li>
+<li><a href="https://github.com/MenoData/Time4J/">Time4J &ndash;
+Advanced date, time and interval library for Java</a> contains a class
+<code>net.time4j.tool.TimezoneRepositoryCompiler</code> that compiles
+<code><abbr>tz</abbr></code> source into a binary format. Time4J is
+available under the <a
+href="https://www.gnu.org/copyleft/lesser.html"><abbr>GNU</abbr> Lesser
+General Public License (<abbr title="Lesser General Public
+License">LGPL</abbr>)</a>.</li>
+<li><abbr>ICU</abbr> (mentioned <a href="#ICU">above</a>) contains compilers and
+Java-based libraries.</li>
+</ul>
+<li><a href="https://nodatime.org">Noda Time &ndash; Date and
+time <abbr>API</abbr> for .NET</a>
+and <a href="http://www.babiej.demon.nl/Tz4Net/main.htm">TZ4Net</a>
+are similar to Joda-Time and Time4J, but for the .NET framework instead of
+Java. They are freely available under the
+Apache License
+and a <abbr>BSD</abbr>-style license, respectively.</li>
+<li><a href="https://en.wikipedia.org/wiki/JavaScript">JavaScript</a>-based
+compilers and libraries include:
+<ul>
+<li><a
+href="https://github.com/kshetline/compact-time-zone-generator">CompactTimeZoneGenerator</a>
+compiles time zone data into a compact form designed for
+JavaScript. It is freely available under a combination of
+the <abbr>MIT</abbr> license and the Apache License.</li>
+<li><a href="https://momentjs.com/timezone/">Moment Timezone</a> is a
+plugin for the <a href="https://momentjs.com">Moment.js</a> date
+manipulation library. It is freely available under the <abbr>MIT</abbr>
+license.</li>
+<li><a href="https://github.com/mde/timezone-js">TimezoneJS.Date</a>'s
+<abbr>API</abbr> is upward compatible with standard JavaScript
+Dates. It is freely available under the Apache License.</li>
+<li><a href="https://github.com/sproutsocial/walltime-js">Walltime-js</a>
+translates <abbr>UT</abbr> to local time. It is freely available under
+the <abbr>MIT</abbr> license.</li>
+</ul>
+<li><a href="https://github.com/JuliaTime/">JuliaTime</a> contains a
+compiler from <code><abbr>tz</abbr></code> source into
+<a href="https://julialang.org/">Julia</a>. It is freely available
+under the <abbr>MIT</abbr> license.</li>
+<li><a href="http://pytz.sourceforge.net">pytz &ndash; World Timezone
+Definitions for Python</a> compiles <code><abbr>tz</abbr></code> source into
+<a href="https://www.python.org">Python</a>.
+It is freely available under a <abbr>BSD</abbr>-style license.</li>
+<li><a href="https://tzinfo.github.io">TZInfo &ndash;
+Ruby Timezone Library</a>
+compiles <code><abbr>tz</abbr></code> source into
+<a href="https://www.ruby-lang.org/en/">Ruby</a>.
+It is freely available under the <abbr>MIT</abbr> license.</li>
+<li>The <a href="http://www.squeaksource.com/Chronos/">Chronos Date/Time
+Library</a> is
+a <a href="https://en.wikipedia.org/wiki/Smalltalk">Smalltalk</a> class
+library that compiles <code><abbr>tz</abbr></code> source into a time
+zone repository whose format
+is either proprietary or an <abbr>XML</abbr>-encoded
+representation.</li>
+<li><a id="Tcl" href="https://tcl.tk">Tcl</a>
+contains a developer-oriented parser that compiles <code><abbr>tz</abbr></code>
+source into text files, along with a runtime that can read those
+files. Tcl is freely available under a <abbr>BSD</abbr>-style
+license.</li>
+</ul>
+<h2 id="binary">Other <code><abbr>tz</abbr></code> binary file readers</h2>
+<ul>
+<li>The <a
+href="https://www.gnu.org/software/libc/"><abbr>GNU</abbr> C
+Library</a>
+has an independent, thread-safe implementation of
+a <code><abbr>tz</abbr></code> binary file reader.
+This library is freely available under the LGPL
+and is widely used in <abbr>GNU</abbr>/Linux systems.</li>
+<li><a href="https://www.gnome.org">GNOME</a>'s
+<a href="https://developer.gnome.org/glib/">GLib</a> has
+a <code><abbr>tz</abbr></code> binary file reader written in C that
+creates a <code>GTimeZone</code> object representing sets
+of <abbr>UT</abbr> offsets.
+It is freely available under the <abbr>LGPL</abbr>.</li>
+<li>The
+<a href="https://github.com/bloomberg/bde/wiki">BDE Standard Library</a>'s
+<code>baltzo::TimeZoneUtil</code> component contains a C++
+implementation of a binary file reader. It is freely available under
+the Apache License.</li>
+<li><a href="https://github.com/google/cctz">CCTZ</a> is a simple C++
+library that translates between <abbr>UT</abbr> and civil time and
+can read binary files. It is freely available under the Apache
+License.</li>
+<li><a href="http://bmsi.com/java/#TZ">ZoneInfo.java</a>
+is a <code><abbr>tz</abbr></code> binary file reader written in Java.
+It is freely available under the <abbr>LGPL</abbr>.</li>
+<li><a href="https://github.com/derickr/timelib">Timelib</a> is a C
+library that reads tz binary files and converts
+time stamps from one time zone or format to another.
+It is used by <a href="https://secure.php.net"><abbr
+title="PHP: Hypertext Preprocessor">PHP</abbr></a>,
+<a href="https://hhvm.com"><abbr title="HipHop Virtual Machine">HHVM</abbr></a>,
+and <a href="https://www.mongodb.com">MongoDB</a>.
+It is freely available under the <abbr>MIT</abbr> license.</li>
+<li><a href="https://github.com/bigeasy/timezone">Timezone</a> is a
+JavaScript library that supports date arithmetic that is time zone
+aware. It is freely available under the <abbr>MIT</abbr> license.</li>
+<li>Tcl, mentioned <a href="#Tcl">above</a>, also contains a
+<code><abbr>tz</abbr></code> binary file reader.</li>
+<li><a href="http://search.cpan.org/perldoc?DateTime::TimeZone::Tzfile">
+DateTime::TimeZone::Tzfile</a>
+is a <code><abbr>tz</abbr></code> binary file reader written in Perl.
+It is freely available under the same terms as Perl
+(dual <abbr>GPL</abbr> and Artistic license).</li>
+<li>The
+public-domain <a href="https://github.com/dbaron/tz.js">tz.js</a>
+library contains a Python tool that
+converts <code><abbr>tz</abbr></code> binary data into
+<abbr>JSON</abbr>-format data suitable for use
+in its JavaScript library for time zone conversion. Dates before 1970
+are not supported.</li>
+<li>The <a
+href="https://hackage.haskell.org/package/timezone-olson">timezone-olson</a>
+package contains <a href="https://www.haskell.org">Haskell</a> code that
+parses and uses <code><abbr>tz</abbr></code> binary data. It is freely
+available under a <abbr>BSD</abbr>-style license.</li>
+</ul>
+<h2 id="software">Other <code><abbr>tz</abbr></code>-based time zone software</h2>
+<ul>
+<li><a href="https://foxclocks.org">FoxClocks</a>
+is an extension for <a href="https://www.google.com/chrome/">Google
+Chrome</a> and for <a
+href="https://developer.mozilla.org/en-US/docs/Mozilla/Tech/Toolkit_API">Mozilla
+Toolkit</a> applications like <a
+href="https://www.mozilla.org/en-US/firefox/new/">Firefox</a> and <a
+href="https://www.mozilla.org/en-US/thunderbird/">Thunderbird</a>.
+It displays multiple clocks in the application window, and has a mapping
+interface to <a href="https://www.google.com/earth/">Google Earth</a>.
+It is freely available under the <abbr>GPL</abbr>.</li>
+<li><a href="https://golang.org">Go programming language</a>
+implementations contain a copy of a 32-bit subset of a recent
+<code><abbr>tz</abbr></code> database in a
+Go-specific format.</li>
+<li><a
+href="http://users.skynet.be/Peter.Verthez/projects/intclock/">International
+clock (intclock)</a> is a clock that displays multiple time zones on
+<abbr>GNU</abbr>/Linux and similar systems. It is freely available
+under the <abbr>GPL</abbr>.</li>
+<li>Microsoft Windows 8.1
+and later has <code><abbr>tz</abbr></code> data and <abbr>CLDR</abbr>
+data (mentioned <a href="#CLDR">below</a>) used by
+<a href="https://en.wikipedia.org/wiki/Windows_Runtime">Windows Runtime</a>
+classes such as <a
+href="https://msdn.microsoft.com/en-us/library/windows/apps/windows.globalization.datetimeformatting.datetimeformatter.aspx"><code>DateTimeFormatter</code></a>.
+<a id="System.TimeZoneInfo"
+href="https://blogs.msdn.microsoft.com/bclteam/2007/06/07/exploring-windows-time-zones-with-system-timezoneinfo-josh-free/">Exploring
+Windows Time Zones with <code>System.TimeZoneInfo</code></a> describes
+the older, proprietary method of Microsoft Windows 2000 and later,
+which stores time zone data in the
+<a href="https://en.wikipedia.org/wiki/Windows_Registry">Windows Registry</a>. The
+<a
+href="https://unicode.org/cldr/charts/latest/supplemental/zone_tzid.html">Zone &rarr;
+Tzid table</a> or <a
+href="https://unicode.org/repos/cldr/trunk/common/supplemental/windowsZones.xml"><abbr>XML</abbr>
+file</a> of the <abbr>CLDR</abbr> data maps proprietary zone IDs
+to <code><abbr>tz</abbr></code> names.
+<li><a
+href="https://www.oracle.com/java/index.html">Oracle
+Java</a> contains a copy of a subset of a recent
+<code><abbr>tz</abbr></code> database in a
+Java-specific format.</li>
+<li><a href="https://www.relativedata.com/time-zone-master">Time Zone
+Master</a> is a Microsoft Windows clock program that can automatically
+download, compile and use <code>tz</code> releases. The Basic version
+is free.</li>
+<li><a
+href="http://veladg.com/velaterra.html">VelaTerra</a> is
+a macOS program. Its developers
+<a href="http://veladg.com/tzoffer.html">offer free
+licenses</a> to <code><abbr>tz</abbr></code> contributors.</li>
+</ul>
+<h2 id="other-dbs">Other time zone databases</h2>
+<ul>
+<li><a href="https://www.astro.com/atlas">Time-zone Atlas</a>
+is Astrodienst's Web version of Shanks and Pottenger's
+time zone history atlases also published in <a
+href="https://astrocom.com/astrology-products/software/acs-atlas-software">software</a>
+form by <a href="https://astrocom.com">ACS-Starcrafts</a>.
+These atlases are extensive but unreliable, as Shanks appears to have
+guessed many <abbr>UT</abbr> offsets and transitions. The atlases cite no
+sources and do not indicate which entries are guesswork.</li>
+<li><a href="https://en.wikipedia.org/wiki/HP-UX">HP-UX</a> has a database in
+its own <code>tztab</code>(4) format.</li>
+<li>Microsoft Windows has proprietary data mentioned
+<a href="#System.TimeZoneInfo">above</a>.</li>
+<li><a href="https://www.worldtimeserver.com">World Time Server</a>
+is another time zone database.</li>
+<li><a href="http://tycho.usno.navy.mil/tzones.html">World Time Zones</a>
+contains data from the Time Service Department of the
+<abbr>US</abbr> Naval Observatory.</li>
+<li>The <a
+href="https://www.iata.org/publications/store/Pages/standard-schedules-information.aspx">Standard
+Schedules Information Manual</a> of the
+International Air Transport Association
+gives current time zone rules for airports served by commercial aviation.</li>
+</ul>
+<h2 id="maps">Maps</h2>
+<ul>
+<li>The <a href="https://www.cia.gov/index.html">United States Central
+Intelligence Agency (<abbr
+title="Central Intelligence Agency">CIA</abbr>)</a> publishes a <a
+href="https://www.cia.gov/library/publications/the-world-factbook/graphics/ref_maps/physical/pdf/standard_time_zones_of_the_world.pdf">time
+zone map</a>; the
+<a
+href="https://www.lib.utexas.edu/maps/world.html">Perry&ndash;Casta&ntilde;eda
+Library Map Collection</a>
+of the University of Texas at Austin has copies of
+recent editions.
+The pictorial quality is good,
+but the maps do not indicate daylight saving time,
+and parts of the data are a few years out of date.</li>
+<li><a href="https://www.worldtimezone.com">Current time around the world
+and standard time zones map of the world</a>
+has several fancy time zone maps; it covers Russia particularly well.
+The maps' pictorial quality is not quite as good as the
+<abbr>CIA</abbr>'s
+but the maps are more up to date.</li>
+<li><a
+href="https://blog.poormansmath.net/how-much-is-time-wrong-around-the-world/">How
+much is time wrong around the world?</a> maps the difference between
+mean solar and standard time, highlighting areas such as western China
+where the two differ greatly. It's a bit out of date, unfortunately.</li>
+</ul>
+<h2 id="boundaries">Time zone boundaries</h2>
+<p>Geographical boundaries between time zone regions are available
+from several <a href="https://en.wikipedia.org/wiki/Geolocation">geolocation</a>
+services and other sources.</p>
+<ul>
+<li>Databases of time zone boundaries include:
+<ul>
+<li><a href="https://github.com/evansiroky/timezone-boundary-builder">Timezone
+Boundary Builder</a> extracts
+<a href="https://www.openstreetmap.org">Open Street Map</a> data to build
+boundaries of <code><abbr>tz</abbr></code> regions.
+Its code is freely available under the <abbr>MIT</abbr> license, and
+its data entries are freely available under the
+<a href="https://opendatacommons.org/licenses/odbl/">Open Data Commons
+Open Database License</a>. The maps' borders appear to be quite accurate.</li>
+<li><a href="http://efele.net/maps/tz/"><abbr>TZ</abbr> timezones
+maps</a> contains <a
+href="https://en.wikipedia.org/wiki/Shapefile">shapefiles</a> of
+sets of <code><abbr>tz</abbr></code> regions. This includes
+<a href="http://efele.net/maps/tz/world/">tz_world</a>, a shapefile
+for all the world's regions. These maps are no longer maintained and
+are superseded by the Timezone Boundary Builder.</li>
+<li><a
+href="https://github.com/straup/whereonearth-timezone">Whereonearth-timezone</a>
+is in <a href="https://tools.ietf.org/html/rfc7946">GeoJSON</a> format
+(Internet <abbr>RFC</abbr> 7946), and combines the
+the tz_world shapefiles with the
+<a href="https://developer.yahoo.com/geo/geoplanet/">GeoPlanet</a>
+dataset.</li>
+</ul></li>
+<li>Programmatic interfaces that map geographical coordinates via tz_world to
+<code><abbr>tz</abbr></code> regions include:
+<ul>
+<li><a href="https://github.com/mj1856/GeoTimeZone">GeoTimeZone</a> is
+written in <a
+href="https://en.wikipedia.org/wiki/C_Sharp_(programming_language)">C#</a>
+and is freely available under the <abbr>MIT</abbr> license.</li>
+<li>The <a href="https://github.com/bradfitz/latlong">latlong package</a>
+is written in Go and is freely available under the Apache License.</li>
+<li><a href="https://github.com/drtimcooper/LatLongToTimezone">LatLongToTimezone</a>,
+in both Java and
+<a href="https://en.wikipedia.org/wiki/Swift_(programming_language)">Swift</a>
+form, is freely available under the MIT license.</li>
+<li>For <a href="https://nodejs.org/en/">Node.js</a>,
+the <a href="https://www.npmjs.com/package/geo-tz">geo-tz module</a>
+is freely available under the MIT license, and
+the <a href="https://www.npmjs.com/package/tz-lookup">tz-lookup module</a>
+is in the public domain.</li>
+<li>The <a
+href="https://github.com/MrMinimal64/timezonefinder">timezonefinder</a>
+library for Python is freely available under the MIT license.
+<li>The <a
+href="https://github.com/gunyarakun/timezone_finder">timezone_finder</a>
+library for Ruby is freely available under the MIT license.</li>
+<li><a href="https://derickrethans.nl/what-time-is-it.html">What Time
+is It Here?</a> applies MongoDB
+geospatial query operators to shapefiles' data.</li>
+</ul></li>
+<li>Free access via a network API, if you register a key, is provided by
+the <a href="http://www.geonames.org/export/web-services.html#timezone">GeoNames Timezone web service</a>,
+the <a href="https://developers.google.com/maps/documentation/timezone/intro">Google Maps Time Zone API</a>, and
+the <a href="https://timezonedb.com">Time Zone Database &amp; API</a>.
+Commercial network API access is provided
+by <a href="https://askgeo.com">AskGeo</a>
+and <a href="https://www.geogarage.com/blog/news-1/post/geogarage-time-zone-api-31">GeoGarage</a>.
+</li>
+<li>"<a
+href="https://stackoverflow.com/questions/16086962/how-to-get-a-time-zone-from-a-location-using-latitude-and-longitude-coordinates/16086964">How
+to get a time zone from a location using latitude and longitude
+coordinates?</a>" discusses other geolocation possibilities.</li>
+<li><a href="http://statoids.com/statoids.html">Administrative
+Divisions of Countries ("Statoids")</a> lists
+political subdivision data related to time zones.</li>
+<li><a href="http://home.kpn.nl/vanadovv/time/Multizones.html">Time
+zone boundaries for multizone countries</a> summarizes legal
+boundaries between time zones within countries.</li>
+<li><a href="http://manifold.net/info/freestuff.shtml">Manifold Software
+&ndash; GIS and Database Tools</a> includes a Manifold-format map of
+world time zone boundaries distributed under the
+<abbr>GPL</abbr>.</li>
+<li>A ship within the <a
+href="https://en.wikipedia.org/wiki/Territorial_waters">territorial
+waters</a> of any nation uses that nation's time. In international
+waters, time zone boundaries are meridians 15&deg; apart, except that
+<abbr>UT</abbr>&minus;12 and <abbr>UT</abbr>+12 are each 7.5&deg;
+wide and are separated by
+the 180&deg; meridian (not by the International Date Line, which is
+for land and territorial waters only). A captain can change ship's
+clocks any time after entering a new time zone; midnight changes are
+common.</li>
+</ul>
+<h2 id="civil">Civil time concepts and history</h2>
+<ul>
+<li><a href="https://www.nist.gov/pml/time-and-frequency-division/popular-links/walk-through-time">A
+Walk through Time</a>
+surveys the evolution of timekeeping.</li>
+<li><a href="http://www.webexhibits.org/daylightsaving/">About Daylight
+Saving Time &ndash; History, rationale, laws &amp; dates</a>
+is an overall history of <abbr>DST</abbr>.</li>
+<li><a href="https://www.w3.org/TR/timezone/">Working with Time Zones</a>
+contains guidelines and best practices for software applications that
+deal with civil time.</li>
+<li><a href="http://seizethedaylight.com/dst/">A Brief
+History of Daylight Saving Time</a> summarizes some of the contentious
+history of <abbr>DST</abbr>.</li>
+<li><a href="https://www.staff.science.uu.nl/~gent0113/idl/idl.htm">A History of
+the International Date Line</a> tells the story of the most important
+time zone boundary.</li>
+<li><a href="http://statoids.com/tconcept.html">Basic Time
+Zone Concepts</a> discusses terminological issues behind time zones.</li>
+</ul>
+<h2 id="national">National histories of legal time</h2>
+<dl>
+<dt>Australia</dt>
+<dd>The Parliamentary Library has commissioned a <a
+href="https://www.aph.gov.au/binaries/library/pubs/rp/2009-10/10rp10.pdf">research
+paper on daylight saving time in Australia</a>.
+The Bureau of Meteorology publishes a list of <a
+href="http://www.bom.gov.au/climate/averages/tables/dst_times.shtml">Implementation
+Dates of Daylight Savings Time within Australia</a>.</dd>
+<dt>Belgium</dt>
+<dd>The Royal Observatory of Belgium maintains a table of <a
+href="http://www.astro.oma.be/GENERAL/INFO/nli001a.html"
+hreflang="nl">time in Belgium (in Dutch)</a>.</dd>
+<dt>Brazil</dt>
+<dd>The Time Service Department of the National Observatory
+records <a href="http://pcdsh01.on.br/DecHV.html"
+hreflang="pt-BR">Brazil's daylight saving time decrees (in
+Portuguese)</a>.</dd>
+<dt>Canada</dt>
+<dd>National Research Council Canada publishes current
+and some older information about <a
+href="https://www.nrc-cnrc.gc.ca/eng/services/time/time_zones.html">time
+zones &amp; daylight saving time</a>.</dd>
+<dt>Chile</dt>
+<dd>The Hydrographic and Oceanographic Service of the Chilean Navy publishes a
+<a href="http://www.horaoficial.cl/historia_hora.html" hreflang="es">history of
+Chile's official time (in Spanish)</a>.</dd>
+<dt>Czech Republic</dt>
+<dd><a href="https://kalendar.beda.cz/kdy-zacina-a-konci-letni-cas"
+hreflang="cs">When daylight saving time starts and ends (in Czech)</a>
+summarizes and cites historical DST regulations.</dd>
+<dt>Germany</dt>
+<dd>The National Institute for Science and Technology maintains the <a
+href="https://www.ptb.de/cms/en/fachabteilungen/abt4/fb-44/ag-441/realisation-of-legal-time-in-germany.html">Realisation
+of Legal Time in Germany</a>.</dd>
+<dt>Israel</dt>
+<dd>The Interior Ministry periodically issues <a
+href="ftp://ftp.cs.huji.ac.il/pub/tz/announcements"
+hreflang="he">announcements (in Hebrew)</a>.</dd>
+<dt>Italy</dt>
+<dd>The National Institute of Metrological Research maintains a
+<a href="http://www.nanospin.eu/res/tf/ora_legale_i.shtml">table of civil time
+(in Italian)</a>.</dd>
+<dt>Mexico</dt>
+<dd>The Investigation and Analysis Service of the Mexican Library of
+Congress has published a <a
+href="http://www.diputados.gob.mx/bibliot/publica/inveyana/polisoc/horver/index.htm"
+hreflang="es">history of Mexican local time (in Spanish)</a>.</dd>
+<dt>Malaysia</dt>
+<dd>See Singapore <a href="#Singapore">below</a>.</dd>
+<dt>Netherlands</dt>
+<dd><a href="https://www.staff.science.uu.nl/~gent0113/wettijd/wettijd.htm"
+hreflang="nl">Legal time in the Netherlands (in Dutch)</a>
+covers the history of local time in the Netherlands from ancient times.</dd>
+<dt>New Zealand</dt>
+<dd>The Department of Internal Affairs maintains a brief <a
+href="https://www.dia.govt.nz/Daylight-Saving-History">History of
+Daylight Saving</a>. The privately-maintained <a
+href="http://astrologyschool.com/nztime.html">History of New Zealand
+time</a> has more details.</dd>
+<dt>Singapore</dt>
+<dd><a id="Singapore"
+href="http://www.math.nus.edu.sg/aslaksen/teaching/timezone.html">Why
+is Singapore in the "Wrong" Time Zone?</a> details the
+history of legal time in Singapore and Malaysia.</dd>
+<dt>United Kingdom</dt>
+<dd><a
+href="https://www.polyomino.org.uk/british-time/">History of
+legal time in Britain</a> discusses in detail the country
+with perhaps the best-documented history of clock adjustments.
+The National Physical Laboratory also maintains an <a
+href="http://www.npl.co.uk/educate-explore/what-is-time/archive-of-summer-time-dates">Archive
+of Summer time dates</a>.</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>
+<dt>Uruguay</dt>
+<dd>The Oceanography, Hydrography, and Meteorology Service of the Uruguayan
+Navy (SOHMA) publishes an annual <a
+href="http://www.armada.mil.uy/Pagina/institucion/dimat/sohma/almanaque.html" hreflang="es">almanac
+(in Spanish)</a>.</dd>
+</dl>
+<h2 id="precision">Precision timekeeping</h2>
+<ul>
+<li><a
+href="http://leapsecond.com/hpan/an1289.pdf">The
+Science of Timekeeping</a> is a thorough introduction
+to the theory and practice of precision timekeeping.</li>
+<li><a href="https://doi.org/10.1007/978-3-319-59909-0">The Science of
+Time 2016</a> contains several freely-readable papers.</li>
+<li><a href="http://www.ntp.org"><abbr
+title="Network Time Protocol">NTP</abbr>: The Network
+Time Protocol</a> (Internet <abbr>RFC</abbr> 5905)
+discusses how to synchronize clocks of
+Internet hosts.</li>
+<li>The <a
+href="https://www.nist.gov/intelligent-systems-division/ieee-1588">Precision
+Time Protocol</a> (<abbr
+title="Institute of Electrical and Electronics Engineers">IEEE</abbr> 1588)
+can achieve submicrosecond clock accuracy on a local area network.</li>
+<li><a
+href="https://tools.ietf.org/html/rfc4833">Timezone
+Options for <abbr title="Dynamic Host Configuration Protocol">DHCP</abbr></a>
+(Internet <abbr>RFC</abbr> 4833)
+specifies a <a
+href="https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol"><abbr>DHCP</abbr></a>
+option for a server to configure
+a client's time zone and daylight saving settings automatically.</li>
+<li><a
+href="https://www.cv.nrao.edu/~rfisher/Ephemerides/times.html">Astronomical
+Times</a> explains more abstruse astronomical time scales like
+<abbr title="Terrestrial Dynamic Time">TDT</abbr>,
+<abbr title="Geocentric Coordinate Time">TCG</abbr>, and
+<abbr title="Barycentric Dynamic Time">TDB</abbr>.
+<a href="https://www.ucolick.org/~sla/leapsecs/timescales.html">Time
+Scales</a> goes into more detail, particularly for historical variants.</li>
+<li>The <a href="https://www.iau.org"><abbr
+title="International Astronomical Union">IAU</abbr></a>'s <a
+href="http://www.iausofa.org"><abbr
+title="Standards Of Fundamental Astronomy">SOFA</abbr></a>
+collection contains C and <a
+href="https://en.wikipedia.org/wiki/Fortran">Fortran</a>
+code for converting among time scales like
+<abbr title="International Atomic Time">TAI</abbr>,
+<abbr>TDB</abbr>, <abbr>TDT</abbr> and
+<abbr>UTC</abbr>.</li>
+<li><a
+href="https://www.giss.nasa.gov/tools/mars24/help/notes.html">Mars24 Sunclock
+&ndash; Time on Mars</a> describes Airy Mean Time (<abbr>AMT</abbr>) and the
+diverse local time
+scales used by each landed mission on Mars.</li>
+<li><a href="http://leapsecond.com">LeapSecond.com</a> is
+dedicated not only to leap seconds but to precise time and frequency
+in general. It covers the state of the art in amateur timekeeping, and
+how the art has progressed over the past few decades.</li>
+<li><a
+href="https://www.iers.org/IERS/EN/Publications/Bulletins/bulletins.html"><abbr
+title="International Earth Rotation and Reference Systems Service">IERS</abbr>
+Bulletins</a> contains official publications of the International
+Earth Rotation and Reference Systems Service, which decides when leap
+seconds occur. The <code>tz</code> code and data support leap seconds
+via an optional "<code>right</code>" configuration, as opposed to the
+default "<code>posix</code>" configuration.</li>
+<li><a href="https://developers.google.com/time/smear">Leap Smear</a>
+discusses how to gradually adjust <abbr>POSIX</abbr> clocks near a
+leap second so that they disagree with <abbr>UTC</abbr> by at most a
+half second, even though every <abbr>POSIX</abbr> minute has exactly
+sixty seconds. This approach works with the default <code>tz</code>
+"<code>posix</code>" configuration, is <a
+href="http://bk1.ntp.org/ntp-stable/README.leapsmear">supported</a> by
+the <abbr>NTP</abbr> reference implementation, and is used by major
+cloud service providers.</li>
+<li>The <a
+href="https://pairlist6.pair.net/mailman/listinfo/leapsecs">Leap
+Second Discussion List</a> covers <a
+href="https://www2.unb.ca/gge/Resources/gpsworld.november99.pdf">McCarthy
+and Klepczynski's 1999 proposal to discontinue leap seconds</a>,
+discussed further in
+<a href="https://www.cl.cam.ac.uk/~mgk25/time/metrologia-leapsecond.pdf">The
+leap second: its history and possible future</a>.
+<a href="https://www.ucolick.org/~sla/leapsecs/"><abbr>UTC</abbr>
+might be redefined
+without Leap Seconds</a> gives pointers on this
+contentious issue, which was active until 2015 and could become active
+again.</li>
+</ul>
+<h2 id="notation">Time notation</h2>
+<ul>
+<li>The <a id="CLDR" href="http://cldr.unicode.org">Unicode Common Locale Data
+Repository (<abbr>CLDR</abbr>) Project</a> has localizations for time
+zone names, abbreviations, identifiers, and formats. For example, it
+contains French translations for "Eastern European Summer Time",
+"<abbr title="Eastern European Summer Time">EEST</abbr>", and
+"Bucharest". Its
+<a href="https://unicode.org/cldr/charts/latest/by_type/">by-type
+charts</a> show these values for many locales. Data values are available in
+both <abbr title="Locale Data Markup Language">LDML</abbr>
+(an <abbr>XML</abbr> format) and <abbr>JSON</abbr>.
+<li>
+<a href="https://www.cl.cam.ac.uk/~mgk25/iso-time.html">A summary of
+the international standard date and time notation</a> is a good
+summary of
+<a
+href="https://www.iso.org/standard/40874.html"><em><abbr>ISO</abbr>
+8601:2004 &ndash; Data elements and interchange formats &ndash; Information
+interchange &ndash; Representation of dates and times</em></a>.</li>
+<li>
+<a href="https://www.w3.org/TR/xmlschema-2/#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://tools.ietf.org/html/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://tools.ietf.org/html/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.</li>
+<li>
+<a href="https://www.hackcraft.net/web/datetime/">Date &amp; Time
+Formats on the Web</a> surveys web- and Internet-oriented date and time
+formats.</li>
+<li>Alphabetic time zone abbreviations should not be used as unique
+identifiers for <abbr>UT</abbr> offsets as they are ambiguous in
+practice. For example, in English-speaking North America
+"<abbr>CST</abbr>" denotes 6 hours behind <abbr>UT</abbr>,
+but in China it denotes 8 hours ahead of <abbr>UT</abbr>,
+and French-speaking North Americans prefer
+"<abbr title="Heure Normale du Centre">HNC</abbr>" to
+"<abbr>CST</abbr>". The <code><abbr>tz</abbr></code>
+database contains English abbreviations for many time stamps;
+unfortunately some of these abbreviations were merely the database maintainers'
+inventions, and these have been removed when possible.</li>
+<li>Numeric time zone abbreviations typically count hours east of
+<abbr>UT</abbr>, e.g., +09 for Japan and
+&minus;10 for Hawaii. However, the <abbr>POSIX</abbr>
+<code><abbr>TZ</abbr></code> environment variable uses the opposite convention.
+For example, one might use <code><abbr>TZ</abbr>="<abbr
+title="Japan Standard Time">JST</abbr>-9"</code> and
+<code><abbr>TZ</abbr>="<abbr title="Hawaii Standard Time">HST</abbr>10"</code>
+for Japan and Hawaii, respectively. If the
+<code><abbr>tz</abbr></code> database is available, it is usually better to use
+settings like <code><abbr>TZ</abbr>="Asia/Tokyo"</code> and
+<code><abbr>TZ</abbr>="Pacific/Honolulu"</code> instead, as this should avoid
+confusion, handle old time stamps better, and insulate you better from
+any future changes to the rules. One should never set
+<abbr>POSIX</abbr> <code><abbr>TZ</abbr></code> to a value like
+<code>"GMT-9"</code>, though, since this would incorrectly imply that
+local time is nine hours ahead of <abbr>UT</abbr> and the time zone
+is called "<abbr>GMT</abbr>".</li>
+</ul>
+<h2 id="see-also">See also</h2>
+<ul>
+<li><a href="theory.html">Theory and pragmatics of the tz code and data</a></li>
+<li><a href="tz-art.html">Time and the Arts</a></li>
+</ul>
+<hr>
+<address>
+This web page is in the public domain, so clarified as of
+2009-05-17 by Arthur David Olson.
+<br>
+Please send corrections to this web page to the
+<a href="mailto:tz@iana.org">time zone mailing list</a>.
+</address>
+</body>
+</html>
diff --git a/tzfile.5 b/tzfile.5
new file mode 100644
index 000000000000..530397f72e67
--- /dev/null
+++ b/tzfile.5
@@ -0,0 +1,190 @@
+.TH TZFILE 5
+.SH NAME
+tzfile \- time zone information
+.SH DESCRIPTION
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+The time zone information files used by
+.BR tzset (3)
+are typically found under a directory with a name like
+.IR /usr/share/zoneinfo .
+These files begin with a 44-byte header containing the following fields:
+.IP * 2
+The magic four-byte ASCII sequence
+.q "TZif"
+identifies the file as a time zone information file.
+.IP *
+A byte identifying the version of the file's format
+(as of 2017, either an ASCII NUL, or
+.q "2",
+or
+.q "3" ).
+.IP *
+Fifteen bytes containing zeros reserved for future use.
+.IP *
+Six four-byte integer values
+written in a standard byte order
+(the high-order byte of the value is written first).
+These values are,
+in order:
+.RS
+.TP
+.I tzh_ttisgmtcnt
+The number of UT/local indicators stored in the file.
+.TP
+.I tzh_ttisstdcnt
+The number of standard/wall indicators stored in the file.
+.TP
+.I tzh_leapcnt
+The number of leap seconds for which data entries are stored in the file.
+.TP
+.I tzh_timecnt
+The number of transition times for which data entries are stored
+in the file.
+.TP
+.I tzh_typecnt
+The number of local time types for which data entries are stored
+in the file (must not be zero).
+.TP
+.I tzh_charcnt
+The number of bytes of time zone abbreviation strings
+stored in the file.
+.RE
+.PP
+The above header is followed by the following fields, whose lengths
+depend on the contents of the header:
+.IP * 2
+.I tzh_timecnt
+four-byte signed integer values sorted in ascending order.
+These values are written in standard byte order.
+Each is used as a transition time (as returned by
+.BR time (2))
+at which the rules for computing local time change.
+.IP *
+.I tzh_timecnt
+one-byte unsigned integer values;
+each one tells which of the different types of local time types
+described in the file is associated with the time period
+starting with the same-indexed transition time.
+These values serve as indices into the next field.
+.IP *
+.I tzh_typecnt
+.I ttinfo
+entries, each defined as follows:
+.in +.5i
+.sp
+.nf
+.ta .5i +\w'unsigned char\0\0'u
+struct ttinfo {
+ int32_t tt_gmtoff;
+ unsigned char tt_isdst;
+ unsigned char tt_abbrind;
+};
+.in -.5i
+.fi
+.sp
+Each structure is written as a four-byte signed integer value for
+.IR tt_gmtoff ,
+in a standard byte order, followed by a one-byte value for
+.I tt_isdst
+and a one-byte value for
+.IR tt_abbrind .
+In each structure,
+.I tt_gmtoff
+gives the number of seconds to be added to UT,
+.I tt_isdst
+tells whether
+.I tm_isdst
+should be set by
+.BR localtime (3)
+and
+.I tt_abbrind
+serves as an index into the array of time zone abbreviation bytes
+that follow the
+.I ttinfo
+structure(s) in the file.
+.IP *
+.I tzh_leapcnt
+pairs of four-byte values, written in standard byte order;
+the first value of each pair gives the nonnegative time
+(as returned by
+.BR time (2))
+at which a leap second occurs;
+the second gives the
+.I total
+number of leap seconds to be applied during the time period
+starting at the given time.
+The pairs of values are sorted in ascending order by time.
+Each transition is for one leap second, either positive or negative;
+transitions always separated by at least 28 days minus 1 second.
+.IP *
+.I tzh_ttisstdcnt
+standard/wall indicators, each stored as a one-byte value;
+they tell whether the transition times associated with local time types
+were specified as standard time or wall clock time,
+and are used when a time zone file is used in handling POSIX-style
+time zone environment variables.
+.IP *
+.I tzh_ttisgmtcnt
+UT/local indicators, each stored as a one-byte value;
+they tell whether the transition times associated with local time types
+were specified as UT or local time,
+and are used when a time zone file is used in handling POSIX-style
+time zone environment variables.
+.PP
+The
+.BR localtime (3)
+function
+uses the first standard-time
+.I ttinfo
+structure in the file
+(or simply the first
+.I ttinfo
+structure in the absence of a standard-time structure)
+if either
+.I tzh_timecnt
+is zero or the time argument is less than the first transition time recorded
+in the file.
+.SS Version 2 format
+For version-2-format time zone files,
+the above header and data are followed by a second header and data,
+identical in format except that
+eight bytes are used for each transition time or leap second time.
+(Leap second counts remain four bytes.)
+After the second header and data comes a newline-enclosed,
+POSIX-TZ-environment-variable-style string for use in handling instants
+after the last transition time stored in the file
+(with nothing between the newlines if there is no POSIX representation for
+such instants).
+The POSIX-style string must agree with the local time type after
+both data's last transition times; for example, given the string
+.q "WET0WEST,M3.5.0,M10.5.0/3"
+then if a last transition time is in July, the transition's local time
+type must specify a daylight-saving time abbreviated
+.q "WEST"
+that is one hour east of UT.
+.SS Version 3 format
+For version-3-format time zone files, the POSIX-TZ-style string may
+use two minor extensions to the POSIX TZ format, as described in
+.BR newtzset (3).
+First, the hours part of its transition times may be signed and range from
+\*-167 through 167 instead of the POSIX-required unsigned values
+from 0 through 24. Second, DST is in effect all year if it starts
+January 1 at 00:00 and ends December 31 at 24:00 plus the difference
+between daylight saving and standard time.
+.PP
+Future changes to the format may append more data.
+.SH SEE ALSO
+.BR time (2),
+.BR localtime (3),
+.BR tzset (3),
+.BR tzselect (8),
+.BR zdump (8),
+.BR zic (8)
+.\" This file is in the public domain, so clarified as of
+.\" 1996-06-05 by Arthur David Olson.
diff --git a/tzfile.5.txt b/tzfile.5.txt
new file mode 100644
index 000000000000..d55ac47fcb27
--- /dev/null
+++ b/tzfile.5.txt
@@ -0,0 +1,129 @@
+TZFILE(5) File Formats Manual TZFILE(5)
+
+NAME
+ tzfile - time zone information
+
+DESCRIPTION
+ The time zone information files used by tzset(3) are typically found
+ under a directory with a name like /usr/share/zoneinfo. These files
+ begin with a 44-byte header containing the following fields:
+
+ * The magic four-byte ASCII sequence "TZif" identifies the file as a
+ time zone information file.
+
+ * A byte identifying the version of the file's format (as of 2017,
+ either an ASCII NUL, or "2", or "3").
+
+ * Fifteen bytes containing zeros reserved for future use.
+
+ * Six four-byte integer values written in a standard byte order (the
+ high-order byte of the value is written first). These values are, in
+ order:
+
+ tzh_ttisgmtcnt
+ The number of UT/local indicators stored in the file.
+
+ tzh_ttisstdcnt
+ The number of standard/wall indicators stored in the file.
+
+ tzh_leapcnt
+ The number of leap seconds for which data entries are stored
+ in the file.
+
+ tzh_timecnt
+ The number of transition times for which data entries are
+ stored in the file.
+
+ tzh_typecnt
+ The number of local time types for which data entries are
+ stored in the file (must not be zero).
+
+ tzh_charcnt
+ The number of bytes of time zone abbreviation strings stored
+ in the file.
+
+ The above header is followed by the following fields, whose lengths
+ depend on the contents of the header:
+
+ * tzh_timecnt four-byte signed integer values sorted in ascending
+ order. These values are written in standard byte order. Each is
+ used as a transition time (as returned by time(2)) at which the rules
+ for computing local time change.
+
+ * tzh_timecnt one-byte unsigned integer values; each one tells which of
+ the different types of local time types described in the file is
+ associated with the time period starting with the same-indexed
+ transition time. These values serve as indices into the next field.
+
+ * tzh_typecnt ttinfo entries, each defined as follows:
+
+ struct ttinfo {
+ int32_t tt_gmtoff;
+ unsigned char tt_isdst;
+ unsigned char tt_abbrind;
+ };
+
+ Each structure is written as a four-byte signed integer value for
+ tt_gmtoff, in a standard byte order, followed by a one-byte value for
+ tt_isdst and a one-byte value for tt_abbrind. In each structure,
+ tt_gmtoff gives the number of seconds to be added to UT, tt_isdst
+ tells whether tm_isdst should be set by localtime(3) and tt_abbrind
+ serves as an index into the array of time zone abbreviation bytes
+ that follow the ttinfo structure(s) in the file.
+
+ * tzh_leapcnt pairs of four-byte values, written in standard byte
+ order; the first value of each pair gives the nonnegative time (as
+ returned by time(2)) at which a leap second occurs; the second gives
+ the total number of leap seconds to be applied during the time period
+ starting at the given time. The pairs of values are sorted in
+ ascending order by time. Each transition is for one leap second,
+ either positive or negative; transitions always separated by at least
+ 28 days minus 1 second.
+
+ * tzh_ttisstdcnt standard/wall indicators, each stored as a one-byte
+ value; they tell whether the transition times associated with local
+ time types were specified as standard time or wall clock time, and
+ are used when a time zone file is used in handling POSIX-style time
+ zone environment variables.
+
+ * tzh_ttisgmtcnt UT/local indicators, each stored as a one-byte value;
+ they tell whether the transition times associated with local time
+ types were specified as UT or local time, and are used when a time
+ zone file is used in handling POSIX-style time zone environment
+ variables.
+
+ The localtime(3) function uses the first standard-time ttinfo structure
+ in the file (or simply the first ttinfo structure in the absence of a
+ standard-time structure) if either tzh_timecnt is zero or the time
+ argument is less than the first transition time recorded in the file.
+
+ Version 2 format
+ For version-2-format time zone files, the above header and data are
+ followed by a second header and data, identical in format except that
+ eight bytes are used for each transition time or leap second time.
+ (Leap second counts remain four bytes.) After the second header and
+ data comes a newline-enclosed, POSIX-TZ-environment-variable-style
+ string for use in handling instants after the last transition time
+ stored in the file (with nothing between the newlines if there is no
+ POSIX representation for such instants). The POSIX-style string must
+ agree with the local time type after both data's last transition times;
+ for example, given the string "WET0WEST,M3.5.0,M10.5.0/3" then if a
+ last transition time is in July, the transition's local time type must
+ specify a daylight-saving time abbreviated "WEST" that is one hour east
+ of UT.
+
+ Version 3 format
+ For version-3-format time zone files, the POSIX-TZ-style string may use
+ two minor extensions to the POSIX TZ format, as described in
+ newtzset(3). First, the hours part of its transition times may be
+ signed and range from 167 through 167 instead of the POSIX-required
+ unsigned values from 0 through 24. Second, DST is in effect all year
+ if it starts January 1 at 00:00 and ends December 31 at 24:00 plus the
+ difference between daylight saving and standard time.
+
+ Future changes to the format may append more data.
+
+SEE ALSO
+ time(2), localtime(3), tzset(3), tzselect(8), zdump(8), zic(8)
+
+ TZFILE(5)
diff --git a/tzfile.h b/tzfile.h
new file mode 100644
index 000000000000..f7f5cafd33bf
--- /dev/null
+++ b/tzfile.h
@@ -0,0 +1,117 @@
+#ifndef TZFILE_H
+
+#define TZFILE_H
+
+/*
+** This file is in the public domain, so clarified as of
+** 1996-06-05 by Arthur David Olson.
+*/
+
+/*
+** This header is for use ONLY with the time conversion code.
+** There is no guarantee that it will remain unchanged,
+** or that it will remain at all.
+** Do NOT copy it to any system include directory.
+** Thank you!
+*/
+
+/*
+** Information about time zone files.
+*/
+
+#ifndef TZDIR
+#define TZDIR "/usr/share/zoneinfo" /* Time zone object file directory */
+#endif /* !defined TZDIR */
+
+#ifndef TZDEFAULT
+#define TZDEFAULT "/etc/localtime"
+#endif /* !defined TZDEFAULT */
+
+#ifndef TZDEFRULES
+#define TZDEFRULES "posixrules"
+#endif /* !defined TZDEFRULES */
+
+/*
+** Each file begins with. . .
+*/
+
+#define TZ_MAGIC "TZif"
+
+struct tzhead {
+ char tzh_magic[4]; /* TZ_MAGIC */
+ char tzh_version[1]; /* '\0' or '2' or '3' as of 2013 */
+ char tzh_reserved[15]; /* reserved; must be zero */
+ char tzh_ttisgmtcnt[4]; /* coded number of trans. time flags */
+ char tzh_ttisstdcnt[4]; /* coded number of trans. time flags */
+ char tzh_leapcnt[4]; /* coded number of leap seconds */
+ char tzh_timecnt[4]; /* coded number of transition times */
+ char tzh_typecnt[4]; /* coded number of local time types */
+ char tzh_charcnt[4]; /* coded number of abbr. chars */
+};
+
+/*
+** . . .followed by. . .
+**
+** tzh_timecnt (char [4])s coded transition times a la time(2)
+** tzh_timecnt (unsigned char)s types of local time starting at above
+** tzh_typecnt repetitions of
+** one (char [4]) coded UT offset in seconds
+** one (unsigned char) used to set tm_isdst
+** one (unsigned char) that's an abbreviation list index
+** tzh_charcnt (char)s '\0'-terminated zone abbreviations
+** tzh_leapcnt repetitions of
+** one (char [4]) coded leap second transition times
+** one (char [4]) total correction after above
+** tzh_ttisstdcnt (char)s indexed by type; if 1, transition
+** time is standard time, if 0,
+** transition time is wall clock time
+** if absent, transition times are
+** assumed to be wall clock time
+** tzh_ttisgmtcnt (char)s indexed by type; if 1, transition
+** time is UT, if 0,
+** transition time is local time
+** if absent, transition times are
+** assumed to be local time
+*/
+
+/*
+** If tzh_version is '2' or greater, the above is followed by a second instance
+** of tzhead and a second instance of the data in which each coded transition
+** time uses 8 rather than 4 chars,
+** then a POSIX-TZ-environment-variable-style string for use in handling
+** instants after the last transition time stored in the file
+** (with nothing between the newlines if there is no POSIX representation for
+** such instants).
+**
+** If tz_version is '3' or greater, the above is extended as follows.
+** First, the POSIX TZ string's hour offset may range from -167
+** through 167 as compared to the POSIX-required 0 through 24.
+** Second, its DST start time may be January 1 at 00:00 and its stop
+** time December 31 at 24:00 plus the difference between DST and
+** standard time, indicating DST all year.
+*/
+
+/*
+** In the current implementation, "tzset()" refuses to deal with files that
+** exceed any of the limits below.
+*/
+
+#ifndef TZ_MAX_TIMES
+#define TZ_MAX_TIMES 2000
+#endif /* !defined TZ_MAX_TIMES */
+
+#ifndef TZ_MAX_TYPES
+/* This must be at least 17 for Europe/Samara and Europe/Vilnius. */
+#define TZ_MAX_TYPES 256 /* Limited by what (unsigned char)'s can hold */
+#endif /* !defined TZ_MAX_TYPES */
+
+#ifndef TZ_MAX_CHARS
+#define TZ_MAX_CHARS 50 /* Maximum number of abbreviation characters */
+ /* (limited by what unsigned chars can hold) */
+#endif /* !defined TZ_MAX_CHARS */
+
+#ifndef TZ_MAX_LEAPS
+#define TZ_MAX_LEAPS 50 /* Maximum number of leap second corrections */
+#endif /* !defined TZ_MAX_LEAPS */
+
+#endif /* !defined TZFILE_H */
diff --git a/tzselect.8 b/tzselect.8
new file mode 100644
index 000000000000..847d6dd45e88
--- /dev/null
+++ b/tzselect.8
@@ -0,0 +1,113 @@
+.TH TZSELECT 8
+.SH NAME
+tzselect \- select a time zone
+.SH SYNOPSIS
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.B tzselect
+[
+.B \*-c
+.I coord
+] [
+.B \*-n
+.I limit
+] [
+.B \*-\*-help
+] [
+.B \*-\*-version
+]
+.SH DESCRIPTION
+The
+.B tzselect
+program asks the user for information about the current location,
+and outputs the resulting time zone description to standard output.
+The output is suitable as a value for the TZ environment variable.
+.PP
+All interaction with the user is done via standard input and standard error.
+.SH OPTIONS
+.TP
+.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
+.I coord.
+Use ISO 6709 notation for
+.I coord,
+that is, a latitude immediately followed by a longitude. The latitude
+and longitude should be signed integers followed by an optional
+decimal point and fraction: positive numbers represent north and east,
+negative south and west. Latitudes with two and longitudes with three
+integer digits are treated as degrees; latitudes with four or six and
+longitudes with five or seven integer digits are treated as
+.I "DDMM, DDDMM, DDMMSS,"
+or
+.I DDDMMSS
+representing
+.I DD
+or
+.I DDD
+degrees,
+.I MM
+minutes,
+and zero or
+.I SS
+seconds, with any trailing fractions represent fractional minutes or
+(if
+.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"
+specifies 40.689\(de\|N, 74.045\(de\|W,
+.B "\*-c\ +4041.4\*-07402.7"
+specifies 40\(de\|41.4\(fm\|N, 74\(de\|2.7\(fm\|W, and
+.B "\*-c\ +404121\*-0740240"
+specifies 40\(de\|41\(fm\|21\(sd\|N, 74\(de\|2\(fm\|40\(sd\|W.
+If
+.I coord
+is not one of the documented forms, the resulting behavior is unspecified.
+.TP
+.BI "\*-n " limit
+When
+.B \*-c
+is used, display the closest
+.I limit
+locations (default 10).
+.TP
+.B "\*-\*-help"
+Output help information and exit.
+.TP
+.B "\*-\*-version"
+Output version information and exit.
+.SH "ENVIRONMENT VARIABLES"
+.TP
+\f3AWK\fP
+Name of a Posix-compliant
+.I awk
+program (default:
+.BR awk ).
+.TP
+\f3TZDIR\fP
+Name of the directory containing time zone data files (default:
+.BR /usr/share/zoneinfo ).
+.SH FILES
+.TP
+\f2TZDIR\fP\f3/iso3166.tab\fP
+Table of ISO 3166 2-letter country codes and country names.
+.TP
+\f2TZDIR\fP\f3/zone1970.tab\fP
+Table of country codes, latitude and longitude, zone names, and
+descriptive comments.
+.TP
+\f2TZDIR\fP\f3/\fP\f2TZ\fP
+Time zone data file for time zone \f2TZ\fP.
+.SH "EXIT STATUS"
+The exit status is zero if a time zone was successfully obtained from the user,
+nonzero otherwise.
+.SH "SEE ALSO"
+newctime(3), tzfile(5), zdump(8), zic(8)
+.SH NOTES
+Applications should not assume that
+.BR tzselect 's
+output matches the user's political preferences.
+.\" This file is in the public domain, so clarified as of
+.\" 2009-05-17 by Arthur David Olson.
diff --git a/tzselect.8.txt b/tzselect.8.txt
new file mode 100644
index 000000000000..991475087bdc
--- /dev/null
+++ b/tzselect.8.txt
@@ -0,0 +1,77 @@
+TZSELECT(8) System Manager's Manual TZSELECT(8)
+
+NAME
+ tzselect - select a time zone
+
+SYNOPSIS
+ tzselect [ -c coord ] [ -n limit ] [ --help ] [ --version ]
+
+DESCRIPTION
+ The tzselect program asks the user for information about the current
+ location, and outputs the resulting time zone description to standard
+ output. 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.
+
+OPTIONS
+ -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 coord.
+ Use ISO 6709 notation for coord, that is, a latitude immediately
+ followed by a longitude. The latitude and longitude should be
+ signed integers followed by an optional decimal point and
+ fraction: positive numbers represent north and east, negative
+ south and west. Latitudes with two and longitudes with three
+ integer digits are treated as degrees; latitudes with four or
+ six and longitudes with five or seven integer digits are treated
+ as DDMM, DDDMM, DDMMSS, or DDDMMSS representing DD or DDD
+ degrees, MM minutes, and zero or SS seconds, with any trailing
+ fractions represent fractional minutes or (if SS is present)
+ seconds. The decimal point is that of the current locale. For
+ example, in the (default) C locale, -c +40.689-074.045 specifies
+ 40.689oN, 74.045oW, -c +4041.4-07402.7 specifies 40o41.4'N,
+ 74o2.7'W, and -c +404121-0740240 specifies 40o41'21''N,
+ 74o2'40''W. If coord is not one of the documented forms, the
+ resulting behavior is unspecified.
+
+ -n limit
+ When -c is used, display the closest limit locations (default
+ 10).
+
+ --help Output help information and exit.
+
+ --version
+ Output version information and exit.
+
+ENVIRONMENT VARIABLES
+ AWK Name of a Posix-compliant awk program (default: awk).
+
+ TZDIR Name of the directory containing time zone data files (default:
+ /usr/share/zoneinfo).
+
+FILES
+ TZDIR/iso3166.tab
+ Table of ISO 3166 2-letter country codes and country names.
+
+ TZDIR/zone1970.tab
+ Table of country codes, latitude and longitude, zone names, and
+ descriptive comments.
+
+ TZDIR/TZ
+ Time zone data file for time zone TZ.
+
+EXIT STATUS
+ The exit status is zero if a time zone was successfully obtained from
+ the user, nonzero otherwise.
+
+SEE ALSO
+ newctime(3), tzfile(5), zdump(8), zic(8)
+
+NOTES
+ Applications should not assume that tzselect's output matches the
+ user's political preferences.
+
+ TZSELECT(8)
diff --git a/tzselect.ksh b/tzselect.ksh
new file mode 100644
index 000000000000..cde80d1be940
--- /dev/null
+++ b/tzselect.ksh
@@ -0,0 +1,561 @@
+#!/bin/bash
+
+PKGVERSION='(tzcode) '
+TZVERSION=see_Makefile
+REPORT_BUGS_TO=tz@iana.org
+
+# Ask the user about the time zone, and output the resulting TZ value to stdout.
+# Interact with the user via stderr and stdin.
+
+# Contributed by Paul Eggert. This file is in the public domain.
+
+# Porting notes:
+#
+# This script requires a Posix-like shell and prefers the extension of a
+# 'select' statement. The 'select' statement was introduced in the
+# Korn shell and is available in Bash and other shell implementations.
+# If your host lacks both Bash and the Korn shell, you can get their
+# source from one of these locations:
+#
+# Bash <https://www.gnu.org/software/bash/>
+# Korn Shell <http://www.kornshell.com/>
+# MirBSD Korn Shell <https://www.mirbsd.org/mksh.htm>
+#
+# For portability to Solaris 9 /bin/sh this script avoids some POSIX
+# features and common extensions, such as $(...) (which works sometimes
+# but not others), $((...)), and $10.
+#
+# This script also uses several features of modern awk programs.
+# If your host lacks awk, or has an old awk that does not conform to Posix,
+# you can use either of the following free programs instead:
+#
+# Gawk (GNU awk) <https://www.gnu.org/software/gawk/>
+# mawk <https://invisible-island.net/mawk/>
+
+
+# Specify default values for environment variables if they are unset.
+: ${AWK=awk}
+: ${TZDIR=`pwd`}
+
+# Output one argument as-is to standard output.
+# Safer than 'echo', which can mishandle '\' or leading '-'.
+say() {
+ printf '%s\n' "$1"
+}
+
+# Check for awk Posix compliance.
+($AWK -v x=y 'BEGIN { exit 123 }') </dev/null >/dev/null 2>&1
+[ $? = 123 ] || {
+ say >&2 "$0: Sorry, your '$AWK' program is not Posix compatible."
+ exit 1
+}
+
+coord=
+location_limit=10
+zonetabtype=zone1970
+
+usage="Usage: tzselect [--version] [--help] [-c COORD] [-n LIMIT]
+Select a time zone interactively.
+
+Options:
+
+ -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 COORD.
+ COORD should use ISO 6709 notation, for example, '-c +4852+00220'
+ for Paris (in degrees and minutes, North and East), or
+ '-c -35-058' for Buenos Aires (in degrees, South and West).
+
+ -n LIMIT
+ Display at most LIMIT locations when -c is used (default $location_limit).
+
+ --version
+ Output version information.
+
+ --help
+ Output this help.
+
+Report bugs to $REPORT_BUGS_TO."
+
+# Ask the user to select from the function's arguments,
+# and assign the selected argument to the variable 'select_result'.
+# Exit on EOF or I/O error. Use the shell's 'select' builtin if available,
+# falling back on a less-nice but portable substitute otherwise.
+if
+ case $BASH_VERSION in
+ ?*) : ;;
+ '')
+ # '; exit' should be redundant, but Dash doesn't properly fail without it.
+ (eval 'set --; select x; do break; done; exit') </dev/null 2>/dev/null
+ esac
+then
+ # Do this inside 'eval', as otherwise the shell might exit when parsing it
+ # even though it is never executed.
+ eval '
+ doselect() {
+ select select_result
+ do
+ case $select_result in
+ "") echo >&2 "Please enter a number in range." ;;
+ ?*) break
+ esac
+ done || exit
+ }
+
+ # Work around a bug in bash 1.14.7 and earlier, where $PS3 is sent to stdout.
+ case $BASH_VERSION in
+ [01].*)
+ case `echo 1 | (select x in x; do break; done) 2>/dev/null` in
+ ?*) PS3=
+ esac
+ esac
+ '
+else
+ doselect() {
+ # Field width of the prompt numbers.
+ select_width=`expr $# : '.*'`
+
+ select_i=
+
+ while :
+ do
+ case $select_i in
+ '')
+ select_i=0
+ for select_word
+ do
+ select_i=`expr $select_i + 1`
+ printf >&2 "%${select_width}d) %s\\n" $select_i "$select_word"
+ done ;;
+ *[!0-9]*)
+ echo >&2 'Please enter a number in range.' ;;
+ *)
+ if test 1 -le $select_i && test $select_i -le $#; then
+ shift `expr $select_i - 1`
+ select_result=$1
+ break
+ fi
+ echo >&2 'Please enter a number in range.'
+ esac
+
+ # Prompt and read input.
+ printf >&2 %s "${PS3-#? }"
+ read select_i || exit
+ done
+ }
+fi
+
+while getopts c:n:t:-: opt
+do
+ case $opt$OPTARG in
+ c*)
+ coord=$OPTARG ;;
+ n*)
+ location_limit=$OPTARG ;;
+ t*) # Undocumented option, used for developer testing.
+ zonetabtype=$OPTARG ;;
+ -help)
+ exec echo "$usage" ;;
+ -version)
+ exec echo "tzselect $PKGVERSION$TZVERSION" ;;
+ -*)
+ say >&2 "$0: -$opt$OPTARG: unknown option; try '$0 --help'"; exit 1 ;;
+ *)
+ say >&2 "$0: try '$0 --help'"; exit 1 ;;
+ esac
+done
+
+shift `expr $OPTIND - 1`
+case $# in
+0) ;;
+*) say >&2 "$0: $1: unknown argument"; exit 1 ;;
+esac
+
+# Make sure the tables are readable.
+TZ_COUNTRY_TABLE=$TZDIR/iso3166.tab
+TZ_ZONE_TABLE=$TZDIR/$zonetabtype.tab
+for f in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE
+do
+ <"$f" || {
+ say >&2 "$0: time zone files are not set up correctly"
+ exit 1
+ }
+done
+
+# If the current locale does not support UTF-8, convert data to current
+# locale's format if possible, as the shell aligns columns better that way.
+# Check the UTF-8 of U+12345 CUNEIFORM SIGN URU TIMES KI.
+! $AWK 'BEGIN { u12345 = "\360\222\215\205"; exit length(u12345) != 1 }' &&
+ { tmp=`(mktemp -d) 2>/dev/null` || {
+ tmp=${TMPDIR-/tmp}/tzselect.$$ &&
+ (umask 77 && mkdir -- "$tmp")
+ };} &&
+ trap 'status=$?; rm -fr -- "$tmp"; exit $status' 0 HUP INT PIPE TERM &&
+ (iconv -f UTF-8 -t //TRANSLIT <"$TZ_COUNTRY_TABLE" >$tmp/iso3166.tab) \
+ 2>/dev/null &&
+ TZ_COUNTRY_TABLE=$tmp/iso3166.tab &&
+ iconv -f UTF-8 -t //TRANSLIT <"$TZ_ZONE_TABLE" >$tmp/$zonetabtype.tab &&
+ TZ_ZONE_TABLE=$tmp/$zonetabtype.tab
+
+newline='
+'
+IFS=$newline
+
+
+# Awk script to read a time zone table and output the same table,
+# with each column preceded by its distance from 'here'.
+output_distances='
+ BEGIN {
+ FS = "\t"
+ while (getline <TZ_COUNTRY_TABLE)
+ if ($0 ~ /^[^#]/)
+ country[$1] = $2
+ country["US"] = "US" # Otherwise the strings get too long.
+ }
+ function abs(x) {
+ return x < 0 ? -x : x;
+ }
+ function min(x, y) {
+ return x < y ? x : y;
+ }
+ function convert_coord(coord, deg, minute, ilen, sign, sec) {
+ if (coord ~ /^[-+]?[0-9]?[0-9][0-9][0-9][0-9][0-9][0-9]([^0-9]|$)/) {
+ degminsec = coord
+ intdeg = degminsec < 0 ? -int(-degminsec / 10000) : int(degminsec / 10000)
+ minsec = degminsec - intdeg * 10000
+ intmin = minsec < 0 ? -int(-minsec / 100) : int(minsec / 100)
+ sec = minsec - intmin * 100
+ deg = (intdeg * 3600 + intmin * 60 + sec) / 3600
+ } else if (coord ~ /^[-+]?[0-9]?[0-9][0-9][0-9][0-9]([^0-9]|$)/) {
+ degmin = coord
+ intdeg = degmin < 0 ? -int(-degmin / 100) : int(degmin / 100)
+ minute = degmin - intdeg * 100
+ deg = (intdeg * 60 + minute) / 60
+ } else
+ deg = coord
+ return deg * 0.017453292519943296
+ }
+ function convert_latitude(coord) {
+ match(coord, /..*[-+]/)
+ return convert_coord(substr(coord, 1, RLENGTH - 1))
+ }
+ function convert_longitude(coord) {
+ match(coord, /..*[-+]/)
+ return convert_coord(substr(coord, RLENGTH))
+ }
+ # Great-circle distance between points with given latitude and longitude.
+ # Inputs and output are in radians. This uses the great-circle special
+ # case of the Vicenty formula for distances on ellipsoids.
+ function gcdist(lat1, long1, lat2, long2, dlong, x, y, num, denom) {
+ dlong = long2 - long1
+ x = cos(lat2) * sin(dlong)
+ y = cos(lat1) * sin(lat2) - sin(lat1) * cos(lat2) * cos(dlong)
+ num = sqrt(x * x + y * y)
+ denom = sin(lat1) * sin(lat2) + cos(lat1) * cos(lat2) * cos(dlong)
+ return atan2(num, denom)
+ }
+ # Parallel distance between points with given latitude and longitude.
+ # This is the product of the longitude difference and the cosine
+ # of the latitude of the point that is further from the equator.
+ # I.e., it considers longitudes to be further apart if they are
+ # nearer the equator.
+ function pardist(lat1, long1, lat2, long2) {
+ return abs(long1 - long2) * min(cos(lat1), cos(lat2))
+ }
+ # The distance function is the sum of the great-circle distance and
+ # the parallel distance. It could be weighted.
+ function dist(lat1, long1, lat2, long2) {
+ return gcdist(lat1, long1, lat2, long2) + pardist(lat1, long1, lat2, long2)
+ }
+ BEGIN {
+ coord_lat = convert_latitude(coord)
+ coord_long = convert_longitude(coord)
+ }
+ /^[^#]/ {
+ here_lat = convert_latitude($2)
+ here_long = convert_longitude($2)
+ line = $1 "\t" $2 "\t" $3
+ sep = "\t"
+ ncc = split($1, cc, /,/)
+ for (i = 1; i <= ncc; i++) {
+ line = line sep country[cc[i]]
+ sep = ", "
+ }
+ if (NF == 4)
+ line = line " - " $4
+ printf "%g\t%s\n", dist(coord_lat, coord_long, here_lat, here_long), line
+ }
+'
+
+# Begin the main loop. We come back here if the user wants to retry.
+while
+
+ echo >&2 'Please identify a location' \
+ 'so that time zone rules can be set correctly.'
+
+ continent=
+ country=
+ region=
+
+ case $coord in
+ ?*)
+ continent=coord;;
+ '')
+
+ # Ask the user for continent or ocean.
+
+ echo >&2 'Please select a continent, ocean, "coord", or "TZ".'
+
+ quoted_continents=`
+ $AWK '
+ BEGIN { FS = "\t" }
+ /^[^#]/ {
+ entry = substr($3, 1, index($3, "/") - 1)
+ if (entry == "America")
+ entry = entry "s"
+ if (entry ~ /^(Arctic|Atlantic|Indian|Pacific)$/)
+ entry = entry " Ocean"
+ printf "'\''%s'\''\n", entry
+ }
+ ' <"$TZ_ZONE_TABLE" |
+ sort -u |
+ tr '\n' ' '
+ echo ''
+ `
+
+ eval '
+ doselect '"$quoted_continents"' \
+ "coord - I want to use geographical coordinates." \
+ "TZ - I want to specify the time zone using the Posix TZ format."
+ continent=$select_result
+ case $continent in
+ Americas) continent=America;;
+ *" "*) continent=`expr "$continent" : '\''\([^ ]*\)'\''`
+ esac
+ '
+ esac
+
+ case $continent in
+ TZ)
+ # Ask the user for a Posix TZ string. Check that it conforms.
+ while
+ echo >&2 'Please enter the desired value' \
+ 'of the TZ environment variable.'
+ echo >&2 'For example, AEST-10 is a zone named AEST' \
+ 'that is 10 hours'
+ echo >&2 'ahead (east) of Greenwich,' \
+ 'with no daylight saving time.'
+ read TZ
+ $AWK -v TZ="$TZ" 'BEGIN {
+ tzname = "(<[[:alnum:]+-]{3,}>|[[:alpha:]]{3,})"
+ time = "(2[0-4]|[0-1]?[0-9])" \
+ "(:[0-5][0-9](:[0-5][0-9])?)?"
+ offset = "[-+]?" time
+ mdate = "M([1-9]|1[0-2])\\.[1-5]\\.[0-6]"
+ jdate = "((J[1-9]|[0-9]|J?[1-9][0-9]" \
+ "|J?[1-2][0-9][0-9])|J?3[0-5][0-9]|J?36[0-5])"
+ datetime = ",(" mdate "|" jdate ")(/" time ")?"
+ tzpattern = "^(:.*|" tzname offset "(" tzname \
+ "(" offset ")?(" datetime datetime ")?)?)$"
+ if (TZ ~ tzpattern) exit 1
+ exit 0
+ }'
+ do
+ say >&2 "'$TZ' is not a conforming Posix time zone string."
+ done
+ TZ_for_date=$TZ;;
+ *)
+ case $continent in
+ coord)
+ case $coord in
+ '')
+ echo >&2 'Please enter coordinates' \
+ 'in ISO 6709 notation.'
+ echo >&2 'For example, +4042-07403 stands for'
+ echo >&2 '40 degrees 42 minutes north,' \
+ '74 degrees 3 minutes west.'
+ read coord;;
+ esac
+ distance_table=`$AWK \
+ -v coord="$coord" \
+ -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
+ "$output_distances" <"$TZ_ZONE_TABLE" |
+ sort -n |
+ sed "${location_limit}q"
+ `
+ regions=`say "$distance_table" | $AWK '
+ BEGIN { FS = "\t" }
+ { print $NF }
+ '`
+ echo >&2 'Please select one of the following' \
+ 'time zone regions,'
+ echo >&2 'listed roughly in increasing order' \
+ "of distance from $coord".
+ doselect $regions
+ region=$select_result
+ TZ=`say "$distance_table" | $AWK -v region="$region" '
+ BEGIN { FS="\t" }
+ $NF == region { print $4 }
+ '`
+ ;;
+ *)
+ # Get list of names of countries in the continent or ocean.
+ countries=`$AWK \
+ -v continent="$continent" \
+ -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
+ '
+ BEGIN { FS = "\t" }
+ /^#/ { next }
+ $3 ~ ("^" continent "/") {
+ ncc = split($1, cc, /,/)
+ for (i = 1; i <= ncc; i++)
+ if (!cc_seen[cc[i]]++) cc_list[++ccs] = cc[i]
+ }
+ END {
+ while (getline <TZ_COUNTRY_TABLE) {
+ if ($0 !~ /^#/) cc_name[$1] = $2
+ }
+ for (i = 1; i <= ccs; i++) {
+ country = cc_list[i]
+ if (cc_name[country]) {
+ country = cc_name[country]
+ }
+ print country
+ }
+ }
+ ' <"$TZ_ZONE_TABLE" | sort -f`
+
+
+ # If there's more than one country, ask the user which one.
+ case $countries in
+ *"$newline"*)
+ echo >&2 'Please select a country' \
+ 'whose clocks agree with yours.'
+ doselect $countries
+ country=$select_result;;
+ *)
+ country=$countries
+ esac
+
+
+ # Get list of names of time zone rule regions in the country.
+ regions=`$AWK \
+ -v country="$country" \
+ -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
+ '
+ BEGIN {
+ FS = "\t"
+ cc = country
+ while (getline <TZ_COUNTRY_TABLE) {
+ if ($0 !~ /^#/ && country == $2) {
+ cc = $1
+ break
+ }
+ }
+ }
+ /^#/ { next }
+ $1 ~ cc { print $4 }
+ ' <"$TZ_ZONE_TABLE"`
+
+
+ # If there's more than one region, ask the user which one.
+ case $regions in
+ *"$newline"*)
+ echo >&2 'Please select one of the following' \
+ 'time zone regions.'
+ doselect $regions
+ region=$select_result;;
+ *)
+ region=$regions
+ esac
+
+ # Determine TZ from country and region.
+ TZ=`$AWK \
+ -v country="$country" \
+ -v region="$region" \
+ -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
+ '
+ BEGIN {
+ FS = "\t"
+ cc = country
+ while (getline <TZ_COUNTRY_TABLE) {
+ if ($0 !~ /^#/ && country == $2) {
+ cc = $1
+ break
+ }
+ }
+ }
+ /^#/ { next }
+ $1 ~ cc && $4 == region { print $3 }
+ ' <"$TZ_ZONE_TABLE"`
+ esac
+
+ # Make sure the corresponding zoneinfo file exists.
+ TZ_for_date=$TZDIR/$TZ
+ <"$TZ_for_date" || {
+ say >&2 "$0: time zone files are not set up correctly"
+ exit 1
+ }
+ esac
+
+
+ # Use the proposed TZ to output the current date relative to UTC.
+ # Loop until they agree in seconds.
+ # Give up after 8 unsuccessful tries.
+
+ extra_info=
+ for i in 1 2 3 4 5 6 7 8
+ do
+ TZdate=`LANG=C TZ="$TZ_for_date" date`
+ UTdate=`LANG=C TZ=UTC0 date`
+ TZsec=`expr "$TZdate" : '.*:\([0-5][0-9]\)'`
+ UTsec=`expr "$UTdate" : '.*:\([0-5][0-9]\)'`
+ case $TZsec in
+ $UTsec)
+ extra_info="
+Selected time is now: $TZdate.
+Universal Time is now: $UTdate."
+ break
+ esac
+ done
+
+
+ # Output TZ info and ask the user to confirm.
+
+ echo >&2 ""
+ echo >&2 "The following information has been given:"
+ echo >&2 ""
+ case $country%$region%$coord in
+ ?*%?*%) say >&2 " $country$newline $region";;
+ ?*%%) say >&2 " $country";;
+ %?*%?*) say >&2 " coord $coord$newline $region";;
+ %%?*) say >&2 " coord $coord";;
+ *) say >&2 " TZ='$TZ'"
+ esac
+ say >&2 ""
+ say >&2 "Therefore TZ='$TZ' will be used.$extra_info"
+ say >&2 "Is the above information OK?"
+
+ doselect Yes No
+ ok=$select_result
+ case $ok in
+ Yes) break
+ esac
+do coord=
+done
+
+case $SHELL in
+*csh) file=.login line="setenv TZ '$TZ'";;
+*) file=.profile line="TZ='$TZ'; export TZ"
+esac
+
+test -t 1 && say >&2 "
+You can make this change permanent for yourself by appending the line
+ $line
+to the file '$file' in your home directory; then log out and log in again.
+
+Here is that TZ value again, this time on standard output so that you
+can use the $0 command in shell scripts:"
+
+say "$TZ"
diff --git a/version b/version
new file mode 100644
index 000000000000..cc61cea271c9
--- /dev/null
+++ b/version
@@ -0,0 +1 @@
+2018e
diff --git a/workman.sh b/workman.sh
new file mode 100755
index 000000000000..4b3b64ae078e
--- /dev/null
+++ b/workman.sh
@@ -0,0 +1,32 @@
+#! /bin/sh
+
+# This file is in the public domain, so clarified as of
+# 2009-05-17 by Arthur David Olson.
+
+# Tell groff not to emit SGR escape sequences (ANSI color escapes).
+GROFF_NO_SGR=1
+export GROFF_NO_SGR
+
+echo ".am TH
+.hy 0
+.na
+..
+.rm }H
+.rm }F" | nroff -man - ${1+"$@"} | perl -ne '
+ binmode STDIN, '\'':encoding(utf8)'\'';
+ binmode STDOUT, '\'':encoding(utf8)'\'';
+ chomp;
+ s/.\010//g;
+ s/\s*$//;
+ if (/^$/) {
+ $sawblank = 1;
+ next;
+ } else {
+ if ($sawblank && $didprint) {
+ print "\n";
+ $sawblank = 0;
+ }
+ print "$_\n";
+ $didprint = 1;
+ }
+'
diff --git a/zdump.8 b/zdump.8
new file mode 100644
index 000000000000..ef611db7cf9e
--- /dev/null
+++ b/zdump.8
@@ -0,0 +1,226 @@
+.TH ZDUMP 8
+.SH NAME
+zdump \- time zone dumper
+.SH SYNOPSIS
+.B zdump
+[
+.I option
+\&... ] [
+.I zonename
+\&... ]
+.SH DESCRIPTION
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+.ie \n(.g .ds - \f(CW-\fP
+.el ds - \-
+.I Zdump
+prints the current time in each
+.I zonename
+named on the command line.
+.PP
+These options are available:
+.TP
+.BI "\*-\*-version"
+Output version information and exit.
+.TP
+.B \*-i
+.I "(This option is experimental: its behavior may change in future versions.)"
+Output a description of time intervals. For each
+.I zonename
+on the command line, output an interval-format description of the
+zone. See
+.q "INTERVAL FORMAT"
+below.
+.TP
+.B \*-v
+Output a verbose description of time intervals.
+For each
+.I zonename
+on the command line,
+print the time at the lowest possible time value,
+the time one day after the lowest possible time value,
+the times both one second before and exactly at
+each detected time discontinuity,
+the time at one day less than the highest possible time value,
+and the time at the highest possible time value.
+Each line is followed by
+.BI isdst= D
+where
+.I D
+is positive, zero, or negative depending on whether
+the given time is daylight saving time, standard time,
+or an unknown time type, respectively.
+Each line is also followed by
+.BI gmtoff= N
+if the given local time is known to be
+.I N
+seconds east of Greenwich.
+.TP
+.B \*-V
+Like
+.BR \*-v ,
+except omit the times relative to the extreme time values.
+This generates output that is easier to compare to that of
+implementations with different time representations.
+.TP
+.BI "\*-c " [loyear,]hiyear
+Cut off interval output at the given year(s).
+Cutoff times are computed using the proleptic Gregorian calendar with year 0
+and with Universal Time (UT) ignoring leap seconds.
+The lower bound is exclusive and the upper is inclusive; for example, a
+.I loyear
+of 1970 excludes a transition occurring at 1970-01-01 00:00:00 UTC but a
+.I hiyear
+of 1970 includes the transition.
+The default cutoff is
+.BR \*-500,2500 .
+.TP
+.BI "\*-t " [lotime,]hitime
+Cut off interval output at the given time(s),
+given in decimal seconds since 1970-01-01 00:00:00
+Coordinated Universal Time (UTC).
+The
+.I zonename
+determines whether the count includes leap seconds.
+As with
+.BR \*-c ,
+the cutoff's lower bound is exclusive and its upper bound is inclusive.
+.SH "INTERVAL FORMAT"
+.I "This format is experimental: it may change in future versions."
+.PP
+The interval format is a compact text representation that is intended
+to be both human- and machine-readable. It consists of an empty line,
+then a line
+.q "TZ=\fIstring\fP"
+where
+.I string
+is a double-quoted string giving the zone name, a second line
+.q "\*- \*- \fIinterval\fP"
+describing the time interval before the first transition if any, and
+zero or more following lines
+.q "\fIdate time interval\fP",
+one line for each transition time and following interval. Fields are
+separated by single tabs.
+.PP
+Dates are in
+.IR yyyy - mm - dd
+format and times are in 24-hour
+.IR hh : mm : ss
+format where
+.IR hh <24.
+Times are in local time immediately after the transition. A
+time interval description consists of a UT offset in signed
+.RI \(+- hhmmss
+format, a time zone abbreviation, and an isdst flag. An abbreviation
+that equals the UT offset is omitted; other abbreviations are
+double-quoted strings unless they consist of one or more alphabetic
+characters. An isdst flag is omitted for standard time, and otherwise
+is a decimal integer that is unsigned and positive (typically 1) for
+daylight saving time and negative for unknown.
+.PP
+In times and in UT offsets with absolute value less than 100 hours,
+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
+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
+.q "\*-"
+or is
+.q "zzz".
+.PP
+In double-quoted strings, escape sequences represent unusual
+characters. The escape sequences are \es for space, and \e", \e\e,
+\ef, \en, \er, \et, and \ev with their usual meaning in the C
+programming language. E.g., the double-quoted string
+\*(lq"CET\es\e"\e\e"\*(rq represents the character sequence \*(lqCET
+"\e\*(rq.\""
+.PP
+.ne 9
+Here is an example of the output, with the leading empty line omitted.
+(This example is shown with tab stops set far enough apart so that the
+tabbed columns line up.)
+.nf
+.sp
+.if \n(.g .ft CW
+.if t .in +.5i
+.if n .in +2
+.nr w \w'1896-01-13 'u
+.ta \nwu +\nwu +\nwu +\nwu
+TZ="Pacific/Honolulu"
+- - -10:31:26 LMT
+1896-01-13 12:01:26 -10:30 HST
+1933-04-30 03 -09:30 HDT 1
+1933-05-21 11 -10:30 HST
+1942-02-09 03 -09:30 HDT 1
+1945-09-30 01 -10:30 HST
+1947-06-08 02:30 -10 HST
+.in
+.if \n(.g .ft
+.sp
+.fi
+Here, local time begins 10 hours, 31 minutes and 26 seconds west of
+UT, and is a standard time abbreviated LMT. Immediately after the
+first transition, the date is 1896-01-13 and the time is 12:01:26, and
+the following time interval is 10.5 hours west of UT, a standard time
+abbreviated HST. Immediately after the second transition, the date is
+1933-04-30 and the time is 03:00:00 and the following time interval is
+9.5 hours west of UT, is abbreviated HDT, and is daylight saving time.
+Immediately after the last transition the date is 1947-06-08 and the
+time is 02:30:00, and the following time interval is 10 hours west of
+UT, a standard time abbreviated HST.
+.PP
+.ne 10
+Here are excerpts from another example:
+.nf
+.sp
+.if \n(.g .ft CW
+.if t .in +.5i
+.if n .in +2
+TZ="Europe/Astrakhan"
+- - +03:12:12 LMT
+1924-04-30 23:47:48 +03
+1930-06-21 01 +04
+1981-04-01 01 +05 1
+1981-09-30 23 +04
+\&...
+2014-10-26 01 +03
+2016-03-27 03 +04
+.in
+.if \n(.g .ft
+.sp
+.fi
+This time zone is east of UT, so its UT offsets are positive. Also,
+many of its time zone abbreviations are omitted since they duplicate
+the text of the UT offset.
+.SH LIMITATIONS
+Time discontinuities are found by sampling the results returned by localtime
+at twelve-hour intervals.
+This works in all real-world cases;
+one can construct artificial time zones for which this fails.
+.PP
+In the
+.B \*-v
+and
+.B \*-V
+output,
+.q "UT"
+denotes the value returned by
+.IR gmtime (3),
+which uses UTC for modern time stamps and some other UT flavor for
+time stamps that predate the introduction of UTC.
+No attempt is currently made to have the output use
+.q "UTC"
+for newer and
+.q "UT"
+for older time stamps, partly because the exact date of the
+introduction of UTC is problematic.
+.SH "SEE ALSO"
+newctime(3), tzfile(5), zic(8)
+.\" This file is in the public domain, so clarified as of
+.\" 2009-05-17 by Arthur David Olson.
diff --git a/zdump.8.txt b/zdump.8.txt
new file mode 100644
index 000000000000..a24d652deac3
--- /dev/null
+++ b/zdump.8.txt
@@ -0,0 +1,144 @@
+ZDUMP(8) System Manager's Manual ZDUMP(8)
+
+NAME
+ zdump - time zone dumper
+
+SYNOPSIS
+ zdump [ option ... ] [ zonename ... ]
+
+DESCRIPTION
+ Zdump prints the current time in each zonename named on the command
+ line.
+
+ These options are available:
+
+ --version
+ Output version information and exit.
+
+ -i (This option is experimental: its behavior may change in future
+ versions.) Output a description of time intervals. For each
+ zonename on the command line, output an interval-format
+ description of the zone. See "INTERVAL FORMAT" below.
+
+ -v Output a verbose description of time intervals. For each
+ zonename on the command line, print the time at the lowest
+ possible time value, the time one day after the lowest possible
+ time value, the times both one second before and exactly at each
+ detected time discontinuity, the time at one day less than the
+ highest possible time value, and the time at the highest
+ possible time value. Each line is followed by isdst=D where D
+ is positive, zero, or negative depending on whether the given
+ time is daylight saving time, standard time, or an unknown time
+ type, respectively. Each line is also followed by gmtoff=N if
+ the given local time is known to be N seconds east of Greenwich.
+
+ -V Like -v, except omit the times relative to the extreme time
+ values. This generates output that is easier to compare to that
+ of implementations with different time representations.
+
+ -c [loyear,]hiyear
+ Cut off interval output at the given year(s). Cutoff times are
+ computed using the proleptic Gregorian calendar with year 0 and
+ with Universal Time (UT) ignoring leap seconds. The lower bound
+ is exclusive and the upper is inclusive; for example, a loyear
+ of 1970 excludes a transition occurring at 1970-01-01 00:00:00
+ UTC but a hiyear of 1970 includes the transition. The default
+ cutoff is -500,2500.
+
+ -t [lotime,]hitime
+ Cut off interval output at the given time(s), given in decimal
+ seconds since 1970-01-01 00:00:00 Coordinated Universal Time
+ (UTC). The zonename determines whether the count includes leap
+ seconds. As with -c, the cutoff's lower bound is exclusive and
+ its upper bound is inclusive.
+
+INTERVAL FORMAT
+ This format is experimental: it may change in future versions.
+
+ The interval format is a compact text representation that is intended
+ to be both human- and machine-readable. It consists of an empty line,
+ then a line "TZ=string" where string is a double-quoted string giving
+ the zone name, a second line "- - interval" describing the time
+ interval before the first transition if any, and zero or more following
+ lines "date time interval", one line for each transition time and
+ following interval. Fields are separated by single tabs.
+
+ Dates are in yyyy-mm-dd format and times are in 24-hour hh:mm:ss format
+ where hh<24. Times are in local time immediately after the transition.
+ A time interval description consists of a UT offset in signed +-hhmmss
+ format, a time zone abbreviation, and an isdst flag. An abbreviation
+ that equals the UT offset is omitted; other abbreviations are double-
+ quoted strings unless they co