README revision 259065
169587Sgreen@(#)README 8.3 269587SgreenThis file is in the public domain, so clarified as of 369587Sgreen2009-05-17 by Arthur David Olson. 469587Sgreen 569587Sgreen$FreeBSD: releng/10.0/usr.sbin/zic/README 192890 2009-05-27 12:18:39Z edwin $ 669587Sgreen 769587Sgreen"What time is it?" -- Richard Deacon as The King 869587Sgreen"Any time you want it to be." -- Frank Baxter as The Scientist 969587Sgreen (from the Bell System film "About Time") 1069587Sgreen 1169587SgreenThe 1989 update of the time zone package featured 1269587Sgreen 1369587Sgreen* POSIXization (including interpretation of POSIX-style TZ environment 1469587Sgreen variables, provided by Guy Harris), 1569587Sgreen* ANSIfication (including versions of "mktime" and "difftime"), 1669587Sgreen* SVIDulation (an "altzone" variable) 1769587Sgreen* MACHination (the "gtime" function) 1869587Sgreen* corrections to some time zone data (including corrections to the rules 1969587Sgreen for Great Britain and New Zealand) 2069587Sgreen* reference data from the United States Naval Observatory for folks who 2169587Sgreen want to do additional time zones 2269587Sgreen* and the 1989 data for Saudi Arabia. 2369587Sgreen 2469587Sgreen(Since this code will be treated as "part of the implementation" in some places 2569587Sgreenand as "part of the application" in others, there's no good way to name 2692555Sdesfunctions, such as timegm, that are not part of the proposed ANSI C standard; 2769587Sgreensuch functions have kept their old, underscore-free names in this update.) 2869587Sgreen 2969587SgreenAnd the "dysize" function has disappeared; it was present to allow compilation 3069587Sgreenof the "date" command on old BSD systems, and a version of "date" is now 3169587Sgreenprovided in the package. The "date" command is not created when you "make all" 3269587Sgreensince it may lack options provided by the version distributed with your 3369587Sgreenoperating system, or may not interact with the system in the same way the 3469587Sgreennative version does. 3576259Sgreen 3669587SgreenSince POSIX frowns on correct leap second handling, the default behavior of 3769587Sgreenthe "zic" command (in the absence of a "-L" option) has been changed to omit 3876259Sgreenleap second information from its output files. 3976259Sgreen 4076259SgreenHere is a recipe for acquiring, building, installing, and testing the 4169587Sgreentz distribution on a GNU/Linux or similar host. 4292555Sdes 4369587Sgreen mkdir tz 4469587Sgreen cd tz 4569587Sgreen wget 'ftp://elsie.nci.nih.gov/pub/tz*.tar.gz' 4669587Sgreen gzip -dc tzcode*.tar.gz | tar -xf - 4769587Sgreen gzip -dc tzdata*.tar.gz | tar -xf - 4869587Sgreen 4969587SgreenBe sure to read the comments in "Makefile" and make any changes needed 5069587Sgreento make things right for your system, especially if you are using some 5169587Sgreenplatform other than GNU/Linux. Then run the following commands, 5269587Sgreensubstituting your desired installation directory for "$HOME/tzdir": 5369587Sgreen 5469587Sgreen make TOPDIR=$HOME/tzdir install 5569587Sgreen $HOME/tzdir/etc/zdump -v America/Los_Angeles 5669587Sgreen 5769587SgreenTo use the new functions, use a "-ltz" option when compiling or linking. 5869587Sgreen 5969587SgreenHistorical local time information has been included here to: 6069587Sgreen 6169587Sgreen* provide a compendium of data about the history of civil time 6269587Sgreen that is useful even if the data are not 100% accurate; 6369587Sgreen 6469587Sgreen* give an idea of the variety of local time rules that have 6569587Sgreen existed in the past and thus an idea of the variety that may be 6669587Sgreen expected in the future; 6769587Sgreen 6869587Sgreen* provide a test of the generality of the local time rule description 6969587Sgreen system. 7069587Sgreen 7169587SgreenThe information in the time zone data files is by no means authoritative; 7276259Sgreenthe files currently do not even attempt to cover all time stamps before 7376259Sgreen1970, and there are undoubtedly errors even for time stamps since 1970. 7469587SgreenIf you know that the rules are different from those in a file, by all means 7569587Sgreenfeel free to change file (and please send the changed version to 7669587Sgreentz@elsie.nci.nih.gov for use in the future). Europeans take note! 7769587Sgreen 7869587SgreenThanks to these Timezone Caballeros who've made major contributions to the 7969587Sgreentime conversion package: Keith Bostic; Bob Devine; Paul Eggert; Robert Elz; 8069587SgreenGuy Harris; Mark Horton; John Mackin; and Bradley White. Thanks also to 8192555SdesMichael Bloom, Art Neilson, Stephen Prince, John Sovereign, and Frank Wales 8292555Sdesfor testing work, and to Gwillim Law for checking local mean time data. 8392555SdesNone of them are responsible for remaining errors. 8492555Sdes 8576259SgreenLook in the ~ftp/pub directory of elsie.nci.nih.gov 8676259Sgreenfor updated versions of these files. 8769587Sgreen 8876259SgreenPlease send comments or information to tz@elsie.nci.nih.gov. 8976259Sgreen