1Date::Manip::TZ(3) User Contributed Perl Documentation Date::Manip::TZ(3)
2
6 Date::Manip::TZ - an interface to the time zone data
7
9 use Date::Manip::TZ;
10 $tz = new Date::Manip::TZ;
11 Data for most (and hopefully all) time zones used around the world have
13 been gathered and is publicly available in the zoneinfo (or Olson)
14 database.
15 This module uses the data from the zoneinfo database to perform various
17 time zone operations.
18
20 Every time zone has some of the following characteristics:
21 name
23 Every time zone has a unique name. In the zoneinfo database, these
24 are something similar to:
25 America/New_York
27 aliases
29 Time zones may have (but are not required to have) one or more
30 aliases. Each alias is unique, and is not the same as any time
31 zone name. An alias can be used in exactly the same way as a name.
32 periods
34 Every time zone is broken up into periods. Each period describes
35 how a portion of time relates to GMT, and how it might be
36 expressed.
37 Each period includes the following information:
39 start time, end time
41 The period begin and ends at certain times. The times are included
42 both as an absolute GMT time, and as a wall clock time. The wall
43 clock start time is the time that will be on a clock just as the
44 period starts (i.e. after a time change). The wall clock end time
45 is the time on a clock immediately before the period ends.
46 offset
48 The entire period has an offset which is how much the wall clock
49 time differs from GMT.
50 abbreviation
52 When expressing the time period, an abbreviation (such as EST) is
53 typically used.
54 daylight saving time flag
56 Every period is categorized as a standard time or a daylight saving
57 time. The flag will be 1 if it is a daylight saving time, or 0 if
58 it is a standard time.
59 Date::Manip includes all of the data for all of the time zones from the
61 zoneinfo database. This data is available from:
62 <ftp://ftp.iana.org/tz/>
64 Additional data from other standards are also used.
66 The zoneinfo database is not necessary in order to use Date::Manip.
68 Instead, all of that data has been extracted and stored in a series of
69 other modules which are used to handle each time zone. In that way,
70 Date::Manip has no dependency on any other source of data.
71 The Date::Manip::Zones document contains detailed information on the
73 data available.
74
76 In all methods, the following variables are used:
77 $zone
79 This is a string which contains a valid time zone name. For
80 example:
81 America/New_York
83 $alias
85 This is a strings which contains a valid time zone name, or a valid
86 time zone alias. For example:
87 America/New_York
89 US/Eastern
90 EST5EDT
91 $abbrev
93 This is a string which contains a valid time zone abbreviation. For
94 example:
95 EST
97 $offset
99 This is a time zone entered as an offset. An offset is either a
100 string of one of the formats:
101 +HH
103 +HHMM
104 +HHMMSS
105 +HH:MM
106 +HH:MM:SS
107 or it can be a list reference:
109 [HH,MM,SS]
111 If a list reference is used, the sign must be included with all
113 values. So, the offset "-05:30" would be the list reference:
114 [-5,-30,0]
116 $dstflag
118 This is always one of the values: std, stdonly, dst, dstonly
119 It defaults to "std" if it is not present. When determining a time
121 zone, it is usually necessary to check a number of different time
122 zone and DST combinations.
123 If $dstflag is "std", it will check both standard and daylight
125 saving times, but will give preference to standard times. If
126 $dstflag is "stdonly", only standard times will be checked.
127 The "dst" flag will search both, but give preference to daylight
129 saving times. The "dstonly" values will only use daylight saving
130 times.
131 $date
133 A date is always a string containing a date in one of the formats:
134 YYYYMMDDHH:MN:SS
136 YYYY-MM-DD-HH:MN:SS
137 YYYYMMDDHHMNSS
138 or a list reference:
140 [Y,M,D,H,MN,S]
142 $isdst
144 This is 0 if a date is in standard time, 1 if it is in daylight
145 saving time.
146 $period
148 A period is a list reference currently containing the following
149 items:
150 [ $dateUT, $dateLT, $offsetstr, $offset, $abbrev, $isdst,
152 $endUT, $endLT, $begUTs, $begLTs, $endUTs, $endLTs ]
153 $dateUT and $dateLT are the starting date of the period (i.e. the
155 first second in a period) in universal (GMT) time and local (wall
156 clock) time. $endUT and $endLT are the end date of the period (i.e.
157 the last second in a period) in universal and local time. These
158 are all stored as list references.
159 $offsetstr is the string representation of the offset ("+05:00:00")
161 and $offset is the corresponding list reference form ([5,0,0]).
162 $abbrev is the abbreviation that applies during this period, and
164 $isdst is 0 or 1 if it is standard or daylight saving time.
165 When accessing the elements in a period, use ONLY positive indices.
167 In other words, to get $endUT, access it as $$period[6], NOT as
168 $$period[-2], since I am considering adding more information to the
169 period description that may speed up performance.
170 $begUTs is the string representation (YYYYMMDDHH:MN:SS) of $begUT.
172 Similar for $begLTs, $endUTs, and $endLTs.
173 The following methods are available:
175 base
177 config
178 err
179 new
180 new_config
181 Please refer to the Date::Manip::Obj documentation for these
182 methods.
183 all_periods
185 @periods = $tz->all_periods($zone,$year);
186 This returns the description of all time zone periods that occur
188 (in full or in part) during the given year. The year is measured
189 in universal (GMT) time.
190 convert
192 convert_to_gmt
193 convert_from_gmt
194 convert_to_local
195 convert_from_local
196 These functions convert a date from one time zone to another.
197 ($err,$date,$offset,$isdst,$abbrev) =
199 $tz->convert($date,$from,$to [,$isdst]);
200 This converts a date in the time zone given by $from to the time
202 zone given by $to.
203 ($err,$date,$offset,$isdst,$abbrev) =
205 $tz->convert_to_gmt($date [,$from] [,$isdst]);
206 This converts a date to GMT. If $from is given, it is the current
208 time zone of the date. If $from is omitted, it defaults to the
209 local time zone.
210 The value of $isdst returned is always 0.
212 ($err,$date,$offset,$isdst,$abbrev) =
214 $tz->convert_from_gmt($date [,$to]);
215 This converts a date from GMT to another time zone. If $to is
217 given, the date is converted to that time zone. Otherwise, it is
218 converted to the local time zone.
219 ($err,$date,$offset,$isdst,$abbrev) =
221 $tz->convert_to_local($date [,$from] [,$isdst]);
222 ($err,$date,$offset,$isdst,$abbrev) =
223 $tz->convert_from_local($date [,$to] [,$isdst]);
224 Similar to the convert_to_gmt and convert_from_gmt functions. If
226 $from or $to are omitted, they default to GMT.
227 If there is any ambiguity about whether $date is in DST or not
229 (i.e. if it is a date that is repeated during a time change due to
230 the clock being moved back), the $isdst option can be passed in as
231 an argument (it should be 0 or 1) to say which time to use. It is
232 ignored in all cases where $date can be determined without that
233 information.
234 The $isdst value passed back is 1 if the converted date is in DST.
236 The $offset value passed back is a list reference containing the
237 offset from GMT. $abbrev passed back is the time zone abbreviation.
238 Error codes are:
240 0 No error
242 1 Invalid arguments
243 2 Invalid FROM zone
244 3 Invalid TO zone
245 4 Invalid date
246 curr_zone
248 $tz->curr_zone();
249 This returns the system time zone. The system time zone is
251 determined using the methods described below in the "DETERMINING
252 THE SYSTEM TIME ZONE" section.
253 This is the time zone that is used by default unless the SetDate or
255 ForceDate config variable is set to a different zone.
256 $tz->curr_zone(1);
258 This clears the system time zone and re-determines it using the
260 methods described below.
261 The main reason to do this is if the curr_zone_methods method is
263 used to change how the time zone is determined.
264 curr_zone_methods
266 $tz->curr_zone_methods(@methods);
267 This sets the list and order of methods to use in determining the
269 local time zone. The various methods available are listed below in
270 the section "DETERMINING THE SYSTEM TIME ZONE".
271 Some methods may require one or more arguments. For example, the
273 method named "mainvar" takes an option that is the name of a
274 variable. The arguments must be included in the @methods list
275 immediately after the method name (so @methods is actually a
276 mixture of method names and arguments).
277 This method may not be used in any environment where taint checking
279 is enabled. If it is, it will issue a warning, but will NOT change
280 the method list.
281 date_period
283 $period = $tz->date_period($date,$zone,$wall_clock [,$isdst]);
284 This returns the period information for the given date. $date
286 defaults to GMT, but may be given as local (i.e. wall clock) time
287 if $wall_clock is non-zero. The period information is described in
288 the periods method below.
289 If a wall clock time is given, no period is returned if the wall
291 clock time doesn't ever appear (such as when a time change results
292 in the clock moving forward "skipping" a period of time). If the
293 wall clock time appears twice (i.e. when a time change results in
294 the clock being set back), the $isdst variable is used. The
295 standard time is used unless $isdst is non-zero. $isdst is ignored
296 except in the case where there are two possible periods.
297 define_abbrev
299 ($err,$val) = $tz->define_abbrev($abbrev,@zone);
300 When encountering an abbreviation, by default, all time zones which
302 ever include the abbreviation will be examine in the order given in
303 the Date::Manip::Zones manual.
304 Occasionally, it may be necessary to change the order. This is true
306 if you are parsing dates in a time zone which uses an abbreviation
307 which is also used in another time zone, and where the other time
308 zone is given preference. As an example, the abbreviation "ADT"
309 will default to the "Atlantic/Bermuda" time zone. If you are in the
310 "America/Halifax" time zone (which also uses that abbreviation),
311 you may want to change the order of time zones.
312 This will take an abbreviation (which must be a known
314 abbreviation... there is no means of defining a totally new
315 abbreviation) and a list of zones. This will set the list of zones
316 that will be checked, and the order in which they are checked, when
317 a date is encountered with the given abbreviation. It is not
318 necessary that the list include every zone that has ever used the
319 abbreviation, but it may not include a zone that has never used it.
320 If $abbrev is "reset", all abbreviations are reset to the standard
322 values. If @zone includes only the element 'reset', the default
323 list for $abbrev is restored.
324 The following error codes are returned:
326 0 No error
328 1 $abbrev is not a valid abbreviation in any time zone
329 2 A zone (returned as $val) is not a valid time zone
330 3 A zone (returned as $val) does not use the abbreviation
331 For more information about the different zones which may correspond
333 to each abbreviation, and the order in which they will be examined
334 by default, refer to the Date::Manip::Zones manual.
335 define_alias
337 $err = $tz->define_alias($alias,$zone);
338 This will define a new alias (or override an existing alias). $zone
340 must be a valid zone or an error is returned.
341 For more information about the different aliases which are set by
343 default, refer to the Date::Manip::Zones manual.
344 If $alias is "reset", all aliases will be reset to the standard
346 values. If $zone is "reset", $alias will be reset to the standard
347 value.
348 define_offset
350 ($err,$val) = $tz->define_offset($offset, [$dstflag,] @zone);
351 This is similar to the define_abbrev method. When an offset is
353 encountered, all time zones which have ever included that offset
354 are checked. This will defined which time zones, and in what order,
355 they should be checked.
356 The zones to both standard and daylight saving times which include
358 the offset (if $dstflag is "std" or "dst") or to only one or the
359 other.
360 If $offset is "reset", all lists are reset to the default values.
362 If @zone includes only the element 'reset', the default list and
363 order is restored for $offset ($dstflag must not be given).
364 The following error codes are returned:
366 0 No error
368 1 $offset is not a valid offset in any time zone
369 2 $offset is not a valid offset in the selected
370 time (if doing "dstonly" or "stdonly")
371 3 A zone (returned as $val) is not a valid time zone
372 4 A zone (returned as $val) does not use the offset
373 5 A zone (returned as $val) does not include the
374 offset in the selected time (if doing "dstonly"
375 or "stdonly")
376 9 Offset is not a valid offset
378 periods
380 @periods = $tz->periods($zone,$year);
381 This returns the description of all time zone periods that begin
383 during the year given. The year is measured in universal (GMT)
384 time.
385 If no time zone period starts in the given year, nothing is
387 returned.
388 @periods = $tz->periods($zone,undef,$year);
390 This returns all periods that begin in any year from 0001 to $year.
392 @periods = $tz->periods($zone,$year0,$year1);
394 This returns all periods that begin in any year from $year0 to
396 $year1.
397 tzdata
399 tzcode
400 $vers = $tz->tzdata();
401 $vers = $tz->tzcode();
402 These return the versions of the tzdata and tzcode packages used to
404 generate the modules.
405 zone
407 $zone = $tz->zone(@args);
408 @zone = $tz->zone(@args);
409 This function will return a list of all zones, or the default zone,
411 which matches all of the supplied information. In scalar context,
412 it will return only the default zone. In list context, it will
413 return all zones.
414 @args may include any of the following items, and the order is not
416 important.
417 A zone name or alias ($alias)
419 A zone abbreviation ($abbrev)
421 An offset ($offset)
423 A dstflag ($dstflag)
425 A date ($date)
427 It is NOT valid to include two of any of the items. Any time zone
429 returned will match all of the data supplied.
430 If an error occurs, undef is returned. If no zone matches, an empty
432 string, or an empty list is returned.
433 The order of the zones will be determined in the following way:
435 If $abbrev is given, the order of time zones will be determined by
437 it (and $dstflag). If $dstflag is "std", all zones which match
438 $abbrev in standard time are included, followed by all that match
439 $abbrev in saving time (but no duplication is allowed). The reverse
440 is true if $dstflag is "dst".
441 If $abbrev is not given, but $offset is, $offset (and $dstflag)
443 will determine the order given. If $dstflag is "std", all zones
444 which match $offset in standard time are included, followed by all
445 that match $offset in saving time (but no duplication is allowed).
446 The reverse is true if $dstflag is "dst".
447 If $date is given, only zones in which $date will appear in a zone
449 that matches all other information are given. $date is a wall clock
450 time.
451 If no $zone, $abbrev, or $offset are entered, the local time zone
453 may be returned (unless $date is entered, and it doesn't exist in
454 the local time zone).
455 NOTE: there is one important thing to note with respect to $dstflag
457 when you are working with a timezone expressed as an offset and a
458 date is passed in. In this case, the default value of $dstflag is
459 "dst" (NOT "stdonly"), and you probably never want to pass in a
460 value of "std" (though passing in "stdonly" is okay).
461 For standard offsets (with no minute component), there is always a
463 standard timezone which matches that offset. For example, the
464 timezone "+0100" matches the timezone "Etc/GMT+01", so you will
465 never get a timezone in daylight saving time if $dstflag is "std".
466 If you want to pass in a date of 2001-07-01-00:00:00 and an
468 timezone of "+0100" and you want to get a timezone that refers to
469 that date as a daylight saving time date, you must use the $dstflag
470 of "dst" (or "dstonly").
471 Because this is almost always the behavior desired, when a zone is
473 passed in as an offset, and a date is passed in, the default
474 $dstflag is "dst" instead of "std". In all other situations, the
475 default is still "std".
476 If the timezone is expressed as an abbreviation, this problem does
478 not occur.
479
481 Date::Manip makes use of three potentially different time zones when
482 working with a date.
483 The first time zone that may be used is the actual local time zone.
485 This is the time zone that the computer is actually running in.
486 The second time zone is the working time zone. Usually, you will want
488 the default time zone to be the local time zone, but occasionally, you
489 may want the default time zone to be different.
490 The third time zone is the actual time zone that was parsed, or set,
492 for a date. If a date contains no time zone information, it will
493 default to the working time zone.
494 The local time zone is determined using the methods described in the
496 following section. Methods exist for locating the zone in one of the
497 system configuration files, determining it by running a system command,
498 or by looking it up in the registry (for Windows operating systems).
499 If all of these methods fail, the local time zone may be set using
500 either the $::TZ or $ENV{TZ} variables. Please note that these should
501 ONLY be used to set the actual local time zone.
502 If you are running in one time zone, but you want to force dates to be
504 specified in an alternate time zone by default, you need to set the
505 working time zone. The working time zone defaults to the local time
506 zone, but this can be changed using either the SetDate or ForceDate
507 config variables. Refer to the Date::Manip::Config manual for more
508 information.
509 Finally, when a date is actually parsed, if it contains any time zone
511 information, the date is stored in that time zone.
512
514 There are a large number of ways available for determining the time
515 zone. Some or all of them may be checked. A list of methods to use is
516 provided by default, and may be overridden by the curr_zone_methods
517 function described above. To override the default order and/or list of
518 methods, just pass in a list of method names (with arguments where
519 necessary), and only those methods will be done, and in the order
520 given.
521 The following methods are available:
523 Method Argument(s) Procedure
525 ====== =========== =========
526 main VAR The main variable named VAR is
528 checked. E.g. "main TZ" checks
529 the variable $::TZ .
530 env TYPE VAR The named environment variable
532 is checked and the type of
533 data stored there (TYPE can
534 be 'zone' or 'offset' which
535 is the number of seconds from
536 UTC).
537 file FILE Look in the given file for any
539 one of the following case
540 insensitive lines:
541 ZONE
542 tz = ZONE
543 zone = ZONE
544 timezone = ZONE
545 ZONE may be quoted (single or
546 double) and whitespace is
547 ignored (except that underscores
548 in the zone name may be replaced
549 by whitespace on some OSes). If
550 the entire line is a zone, it must
551 be the first non-blank non-comment
552 line in the file.
553 command COMMAND Runs a command which produces
555 a time zone as the output.
556 cmdfield COMMAND N Runs a command which produces
558 whitespace separated fields,
559 the Nth one containing the
560 time zone (fields are numbered
561 starting at 0, or from the
562 end starting at -1).
563 gmtoff Uses the current offset from
565 GMT to come up with a best guess.
566 tzdata FILE DIR This uses a system config file that
568 contains a pointer to the local tzdata
569 files to determine the timezone. On
570 many operating systems, use:
571 tzdata /etc/localtime /usr/share/zoneinfo
573 FILE is the system file. DIR is the
575 directory where the tzdata files are stored.
576 The config file is either a link to a file
578 in the tzdata directory or a copy of one
579 of the files.
580 registry Look up the value in the
582 Windows registry. This is only
583 available to hosts running a
584 Windows operating system.
585 Note that the "main" and "env" methods should only be used to specify
587 the actual time zone the system is running in. Use the SetDate and
588 ForceDate config variables to specify an alternate time zone that you
589 want to work in.
590 By default, the following methods are checked (in the order given) on
592 Unix systems:
593 main TZ
595 env zone TZ
596 file /etc/TIMEZONE
597 file /etc/timezone
598 file /etc/sysconfig/clock
599 file /etc/default/init
600 command "/bin/date +%Z"
601 command "/usr/bin/date +%Z"
602 command "/usr/local/bin/date +%Z"
603 cmdfield /bin/date -2
604 cmdfield /usr/bin/date -2
605 cmdfield /usr/local/bin/date -2
606 command "/bin/date +%z"
607 command "/usr/bin/date +%z"
608 command "/usr/local/bin/date +%z"
609 tzdata /etc/localtime /usr/share/zoneinfo
610 gmtoff
611 The default methods for Windows systems are:
613 main TZ
615 env zone TZ
616 registry
617 gmtoff
618 The default methods for VMS systems are:
620 main TZ
622 env zone TZ
623 env zone SYS$TIMEZONE_NAME
624 env zone UCX$TZ
625 env zone TCPIP$TZ
626 env zone MULTINET_TIMEZONE
627 env offset SYS$TIMEZONE_DIFFERENTIAL
628 gmtoff
629 The default methods for all other systems are:
631 main TZ
633 env zone TZ
634 gmtoff
635 If anyone wants better support for a specific OS, please contact me and
637 we'll coordinate adding it.
638 In all cases, the value returned from the method may be any of the
640 following:
641 the full name of a time zone (e.g. America/New_York)
643 or an alias
644 an abbreviation (e.g. EDT) which will be used to
646 determine the zone if possible
647 an offset (+hh, +hhmn, +hh:mm, +hh:mm:ss) from GMT
649 The Date::Manip::Zones module contains information about the time zones
651 and aliases available, and what time zones contain the abbreviations.
652
654 The design decisions made in writing this module may cause some
655 questions (and probably complaints). The time zone modules are all
656 generated using scripts (included in the Date::Manip distribution)
657 which use the standard tzdata tools to parse the tzdata files and store
658 that information in perl modules.
659 I'd like to address some of them, to avoid answering some of the "why
661 did you do it that way" remarks. I do welcome discussion about these
662 decisions... but preferably after you understand why those decisions
663 were made so that that we have an informed basis to begin a discussion.
664 Why not use existing zoneinfo files
666 Some people will probably think that I should have written an
667 interface to the zoneinfo files which are distributed with most
668 operating systems. Although I considered doing that, I rejected
669 the idea for two reasons.
670 First, not all operating systems come with the zoneinfo databases
672 in a user accessible state (Microsoft for example). Even those
673 that do include them store the information in various formats and
674 locations. In order to bypass all that, I have included the data
675 directly in these modules.
676 Second, as I was doing my initial investigations into this, I ran
678 into a bug in the Solaris zoneinfo tools (long since fixed I'm
679 sure). I decided then that I didn't want to depend on an
680 implementation where I could not control and fix the bugs.
681 Why not use the native tzdata files
683 Another decision people may question is that I parse the tzdata
684 files and store the data from them in a large number of perl
685 modules instead of creating an interface to the tzdata files
686 directly. This was done solely for the sake of speed. Date::Manip
687 is already a slow module. I didn't want to slow it down further by
688 doing the complex parsing required to interpret the tzdata files
689 while manipulating dates. By storing the data in these modules,
690 there is little or no parsing done while using Date::Manip modules.
691 It costs a little disk space to store this information... but very
692 little of it is actually loaded at runtime (time zone data is only
693 loaded when the time zone is actually referred to), so I feel it's
694 a good tradeoff.
695 Why store the information in so many files
697 The data from the native tzdata files are parsed and stored in two
698 sets of modules. These include almost 500 Date::Manip::Offset::*
699 modules and almost 450 Date::Manip::TZ::* modules.
700 I note that on my linux box, /usr/share/zoneinfo (which contains
702 data files generated from the tzdata files) contains over 1700
703 files, so I'm not doing anything "new" by breaking up the
704 information into separate files. And doing so has a huge impact on
705 performance... it is not necessary to load and/or manipulate data
706 from time zones which are not in use.
707 The minute I made the decision to distribute the timezone
709 information myself, as opposed to using the system version, it was
710 a given that there would be a lot of files.
711 These modules are loaded only when the time zone or offset is
713 actually used, so, unless dates from around the world are being
714 parsed, only a very small number of these modules will actually be
715 loaded. In many applications, only a single TZ module will be
716 loaded. If parsing dates which have timezone information stored as
717 offsets, one or two Offset modules will also be loaded.
718 The disk space seems excessive
720 Currently, the disk usage of the perl files is around 9 MB. Total
721 disk usage for /usr/share/zoneinfo on my computer is around 4 MB.
722 There are a couple of differences.
723 The primary difference is that the zoneinfo files are stored in a
725 binary (and hence, more compressed) version, where the perl modules
726 have all the data in pure text.
727 Since these are all automatically generated and used, it may be
729 beneficial to store the data in some packed binary format instead
730 of the fully expanded text form that is currently in use. This
731 would decrease the disk space usage, and might improve performance.
732 However, the performance improvement would happen only once per
733 timezone, and would make for more complicated code, so I'm not very
734 interested in pursuing this.
735 Another aspect of the current modules is that they all include pod
737 documentation. Although not necessary, this allows users to easily
738 see what modules handle which time zones, and that's nice. It also
739 allows me to use pod_coverage tests for the module which is a nice
740 check to make sure that the documentation is accurate.
741 All told, I don't consider the disk usage excessive at all.
743
745 Unable to determine Time Zone
746 When using Date::Manip, when the module is initialized, it must be
747 able to determine the local time zone. If it fails to do so, an
748 error will occur:
749 Unable to determine Time Zone
751 and the script will exit.
753 In the past, this was the most common problem with using
755 Date::Manip . With the release of 6.00, this problem should be
756 significantly less common. If you do get this error, please refer
757 to the section above DETERMINING THE SYSTEM TIME ZONE for
758 information about determining the local time zone. I am also
759 interested in hearing about this so that I can update the default
760 list of methods to be able to determine the local time zone better.
761 Asia/Jerusalem time zone
763 The Asia/Jerusalem time zone has a non-standard way of specifying
764 the start and end of Daylight Saving Time based on the Hebrew
765 calendar.
766 As a result, there is no way to specify a simple rule to define
768 time zone changes for all years in the future. As such, this module
769 supports all time zone changes currently specified in the zoneinfo
770 database (which currently goes to the year 2037) but does not
771 attempt to correctly handle zone changes beyond that date. As a
772 result, Date::Manip should not be used to parse dates in the
773 Jerusalem time zone that are far enough in the future that
774 information is not included in the current version of the zoneinfo
775 database.
776 LMT and zzz abbreviations
778 Both the LMT and zzz abbreviations are used in the zoneinfo
779 databases. LMT is use for most time zones for the times before the
780 Gregorian calendar was adopted, and zzz is used for a few where the
781 time zone was created and no description of dates prior to that are
782 supported. Both LMT and zzz are basically ignored in parsing dates
783 (because there is no reasonable way to determine which zone they
784 are referring to), and will be treated as the local time zone
785 regardless.
786
788 None known.
789
791 Please refer to the Date::Manip::Problems documentation for information
792 on submitting bug reports or questions to the author.
793
795 Date::Manip - main module documentation
796
798 This script is free software; you can redistribute it and/or modify it
799 under the same terms as Perl itself.
800
802 Sullivan Beck (sbeck@cpan.org)
803perl v5.30.2 2020-04-27 Date::Manip::TZ(3)