11590Srgrimes@(#)README 8.3 2140392SrwatsonThis file is in the public domain, so clarified as of 397377Sdes2009-05-17 by Arthur David Olson. 41590Srgrimes 597377Sdes$FreeBSD$ 697377Sdes 797377Sdes"What time is it?" -- Richard Deacon as The King 897377Sdes"Any time you want it to be." -- Frank Baxter as The Scientist 997377Sdes (from the Bell System film "About Time") 101590Srgrimes 111590SrgrimesThe 1989 update of the time zone package featured 121590Srgrimes 131590Srgrimes* POSIXization (including interpretation of POSIX-style TZ environment 141590Srgrimes variables, provided by Guy Harris), 151590Srgrimes* ANSIfication (including versions of "mktime" and "difftime"), 161590Srgrimes* SVIDulation (an "altzone" variable) 171590Srgrimes* MACHination (the "gtime" function) 18140392Srwatson* corrections to some time zone data (including corrections to the rules 19140392Srwatson for Great Britain and New Zealand) 20140392Srwatson* reference data from the United States Naval Observatory for folks who 21140392Srwatson want to do additional time zones 22140392Srwatson* and the 1989 data for Saudi Arabia. 23140392Srwatson 24140392Srwatson(Since this code will be treated as "part of the implementation" in some places 25140392Srwatsonand as "part of the application" in others, there's no good way to name 26140392Srwatsonfunctions, such as timegm, that are not part of the proposed ANSI C standard; 27140392Srwatsonsuch functions have kept their old, underscore-free names in this update.) 28140392Srwatson 29140392SrwatsonAnd the "dysize" function has disappeared; it was present to allow compilation 30140392Srwatsonof the "date" command on old BSD systems, and a version of "date" is now 31140392Srwatsonprovided in the package. The "date" command is not created when you "make all" 32140392Srwatsonsince it may lack options provided by the version distributed with your 33140392Srwatsonoperating system, or may not interact with the system in the same way the 34140392Srwatsonnative version does. 35140392Srwatson 36140392SrwatsonSince POSIX frowns on correct leap second handling, the default behavior of 37140392Srwatsonthe "zic" command (in the absence of a "-L" option) has been changed to omit 38140392Srwatsonleap second information from its output files. 39140392Srwatson 40140392SrwatsonHere is a recipe for acquiring, building, installing, and testing the 41140392Srwatsontz distribution on a GNU/Linux or similar host. 42140392Srwatson 431590Srgrimes mkdir tz 441590Srgrimes cd tz 451590Srgrimes wget 'ftp://elsie.nci.nih.gov/pub/tz*.tar.gz' 461590Srgrimes gzip -dc tzcode*.tar.gz | tar -xf - 471590Srgrimes gzip -dc tzdata*.tar.gz | tar -xf - 481590Srgrimes 491590SrgrimesBe sure to read the comments in "Makefile" and make any changes needed 501590Srgrimesto make things right for your system, especially if you are using some 511590Srgrimesplatform other than GNU/Linux. Then run the following commands, 521590Srgrimessubstituting your desired installation directory for "$HOME/tzdir": 531590Srgrimes 541590Srgrimes make TOPDIR=$HOME/tzdir install 551590Srgrimes $HOME/tzdir/etc/zdump -v America/Los_Angeles 561590Srgrimes 571590SrgrimesTo use the new functions, use a "-ltz" option when compiling or linking. 581590Srgrimes 591590SrgrimesHistorical local time information has been included here to: 601590Srgrimes 6114440Smarkm* provide a compendium of data about the history of civil time 621590Srgrimes that is useful even if the data are not 100% accurate; 631590Srgrimes 641590Srgrimes* give an idea of the variety of local time rules that have 651590Srgrimes existed in the past and thus an idea of the variety that may be 66127848Scharnier expected in the future; 671590Srgrimes 681590Srgrimes* provide a test of the generality of the local time rule description 69127848Scharnier system. 7028099Scharnier 711590SrgrimesThe information in the time zone data files is by no means authoritative; 72127848Scharnierthe files currently do not even attempt to cover all time stamps before 73127848Scharnier1970, and there are undoubtedly errors even for time stamps since 1970. 74127848ScharnierIf you know that the rules are different from those in a file, by all means 751590Srgrimesfeel free to change file (and please send the changed version to 761590Srgrimestz@elsie.nci.nih.gov for use in the future). Europeans take note! 771590Srgrimes 7877220SmarkmThanks to these Timezone Caballeros who've made major contributions to the 791590Srgrimestime conversion package: Keith Bostic; Bob Devine; Paul Eggert; Robert Elz; 80161815ScsjpGuy Harris; Mark Horton; John Mackin; and Bradley White. Thanks also to 81161815ScsjpMichael Bloom, Art Neilson, Stephen Prince, John Sovereign, and Frank Wales 82161815Scsjpfor testing work, and to Gwillim Law for checking local mean time data. 83161815ScsjpNone of them are responsible for remaining errors. 84161815Scsjp 851590SrgrimesLook in the ~ftp/pub directory of elsie.nci.nih.gov 861590Srgrimesfor updated versions of these files. 87200462Sdelphij 8877220SmarkmPlease send comments or information to tz@elsie.nci.nih.gov. 891590Srgrimes