zic.tproj/README

   1 @(#)README      7.11
   2
   3 "What time is it?" -- Richard Deacon as The King
   4 "Any time you want it to be." -- Frank Baxter as The Scientist
   5                                         (from the Bell System film "About Time")
   6
   7 The 1989 update of the time zone package featured
   8
   9 *       POSIXization (including interpretation of POSIX-style TZ environment
  10         variables, provided by Guy Harris),
  11 *       ANSIfication (including versions of "mktime" and "difftime"),
  12 *       SVIDulation (an "altzone" variable)
  13 *       MACHination (the "gtime" function)
  14 *       corrections to some time zone data (including corrections to the rules
  15         for Great Britain and New Zealand)
  16 *       reference data from the United States Naval Observatory for folks who
  17         want to do additional time zones
  18 *       and the 1989 data for Saudi Arabia.
  19
  20 (Since this code will be treated as "part of the implementation" in some places
  21 and as "part of the application" in others, there's no good way to name
  22 functions, such as timegm, that are not part of the proposed ANSI C standard;
  23 such functions have kept their old, underscore-free names in this update.)
  24
  25 And the "dysize" function has disappeared; it was present to allow compilation
  26 of the "date" command on old BSD systems, and a version of "date" is now
  27 provided in the package.  The "date" command is not created when you "make all"
  28 since it may lack options provided by the version distributed with your
  29 operating system, or may not interact with the system in the same way the
  30 native version does.
  31
  32 Since POSIX frowns on correct leap second handling, the default behavior of
  33 the "zic" command (in the absence of a "-L" option) has been changed to omit
  34 leap second information from its output files.
  35
  36 Here is a recipe for acquiring, building, installing, and testing the
  37 tz distribution on a GNU/Linux or similar host.
  38
  39         mkdir tz
  40         cd tz
  41         wget 'ftp://elsie.nci.nih.gov/pub/tz*.tar.gz'
  42         gzip -dc tzcode*.tar.gz | tar -xf -
  43         gzip -dc tzdata*.tar.gz | tar -xf -
  44
  45 Be sure to read the comments in "Makefile" and make any changes needed
  46 to make things right for your system, especially if you are using some
  47 platform other than GNU/Linux.  Then run the following commands,
  48 substituting your desired installation directory for "$HOME/tzdir":
  49
  50         make TOPDIR=$HOME/tzdir install
  51         $HOME/tzdir/etc/zdump -v America/Los_Angeles
  52
  53 To use the new functions, use a "-ltz" option when compiling or linking.
  54
  55 Historical local time information has been included here not because it
  56 is particularly useful, but rather to:
  57
  58 *       give an idea of the variety of local time rules that have
  59         existed in the past and thus an idea of the variety that may be
  60         expected in the future;
  61
  62 *       provide a test of the generality of the local time rule description
  63         system.
  64
  65 The information in the time zone data files is by no means authoritative;
  66 if you know that the rules are different from those in a file, by all means
  67 feel free to change file (and please send the changed version to
  68 tz@elsie.nci.nih.gov for use in the future).  Europeans take note!
  69
  70 Thanks to these Timezone Caballeros who've made major contributions to the
  71 time conversion package:  Keith Bostic; Bob Devine; Paul Eggert; Robert Elz;
  72 Guy Harris; Mark Horton; John Mackin; and Bradley White.  Thanks also to
  73 Michael Bloom, Art Neilson, Stephen Prince, John Sovereign, and Frank Wales
  74 for testing work, and to Gwillim Law for checking local mean time data.
  75 None of them are responsible for remaining errors.
  76
  77 Look in the ~ftp/pub directory of elsie.nci.nih.gov
  78 for updated versions of these files.
  79
  80 Please send comments or information to tz@elsie.nci.nih.gov.