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
7The 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
21and as "part of the application" in others, there's no good way to name
22functions, such as timegm, that are not part of the proposed ANSI C standard;
23such functions have kept their old, underscore-free names in this update.)
24
25And the "dysize" function has disappeared; it was present to allow compilation
26of the "date" command on old BSD systems, and a version of "date" is now
27provided in the package. The "date" command is not created when you "make all"
28since it may lack options provided by the version distributed with your
29operating system, or may not interact with the system in the same way the
30native version does.
31
32Since POSIX frowns on correct leap second handling, the default behavior of
33the "zic" command (in the absence of a "-L" option) has been changed to omit
34leap second information from its output files.
35
36Here is a recipe for acquiring, building, installing, and testing the
37tz 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
45Be sure to read the comments in "Makefile" and make any changes needed
46to make things right for your system, especially if you are using some
47platform other than GNU/Linux. Then run the following commands,
48substituting your desired installation directory for "$HOME/tzdir":
49
50 make TOPDIR=$HOME/tzdir install
51 $HOME/tzdir/etc/zdump -v America/Los_Angeles
52
53To use the new functions, use a "-ltz" option when compiling or linking.
54
55Historical local time information has been included here not because it
56is 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
65The information in the time zone data files is by no means authoritative;
66if you know that the rules are different from those in a file, by all means
67feel free to change file (and please send the changed version to
68tz@elsie.nci.nih.gov for use in the future). Europeans take note!
69
70Thanks to these Timezone Caballeros who've made major contributions to the
71time conversion package: Keith Bostic; Bob Devine; Paul Eggert; Robert Elz;
72Guy Harris; Mark Horton; John Mackin; and Bradley White. Thanks also to
73Michael Bloom, Art Neilson, Stephen Prince, John Sovereign, and Frank Wales
74for testing work, and to Gwillim Law for checking local mean time data.
75None of them are responsible for remaining errors.
76
77Look in the ~ftp/pub directory of elsie.nci.nih.gov
78for updated versions of these files.
79
80Please send comments or information to tz@elsie.nci.nih.gov.
81