CVS commit: src/lib/libc/time

["Christos Zoulas" <christos%netbsd.org@localhost>]

Module Name:    src
Committed By:   christos
Date:           Fri Sep 20 19:06:54 UTC 2013

Modified Files:
        src/lib/libc/time: Makefile Theory checktab.awk ctime.3 difftime.c
            localtime.c private.h strftime.3 strftime.c tz-link.htm tzfile.5
            tzfile.h tzselect.8 tzselect.ksh tzset.3 version.h zdump.8 zdump.c
            zic.8 zic.c

Log Message:
Welcome to tzcode 2013e:

  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
    time stamps 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 Zoulos.)

    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 time stamps 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 time stamps.  The data 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://time.nist.gov/pub/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 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 time stamps 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.)


To generate a diff of this commit:
cvs rdiff -u -r1.14 -r1.15 src/lib/libc/time/Makefile \
    src/lib/libc/time/difftime.c
cvs rdiff -u -r1.13 -r1.14 src/lib/libc/time/Theory
cvs rdiff -u -r1.5 -r1.6 src/lib/libc/time/checktab.awk
cvs rdiff -u -r1.47 -r1.48 src/lib/libc/time/ctime.3
cvs rdiff -u -r1.77 -r1.78 src/lib/libc/time/localtime.c
cvs rdiff -u -r1.29 -r1.30 src/lib/libc/time/private.h \
    src/lib/libc/time/strftime.3
cvs rdiff -u -r1.28 -r1.29 src/lib/libc/time/strftime.c
cvs rdiff -u -r1.11 -r1.12 src/lib/libc/time/tz-link.htm \
    src/lib/libc/time/tzfile.h
cvs rdiff -u -r1.19 -r1.20 src/lib/libc/time/tzfile.5
cvs rdiff -u -r1.4 -r1.5 src/lib/libc/time/tzselect.8
cvs rdiff -u -r1.8 -r1.9 src/lib/libc/time/tzselect.ksh
cvs rdiff -u -r1.25 -r1.26 src/lib/libc/time/tzset.3
cvs rdiff -u -r1.1 -r1.2 src/lib/libc/time/version.h
cvs rdiff -u -r1.10 -r1.11 src/lib/libc/time/zdump.8
cvs rdiff -u -r1.30 -r1.31 src/lib/libc/time/zdump.c
cvs rdiff -u -r1.20 -r1.21 src/lib/libc/time/zic.8
cvs rdiff -u -r1.42 -r1.43 src/lib/libc/time/zic.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.