1Date::Manip::TZ(3) User Contributed Perl Documentation Date::Manip::TZ(3)
2
3
4
6 Date::Manip::TZ - an interface to the time zone data
7
9 use Date::Manip::TZ;
10 $tz = new Date::Manip::TZ;
11
12 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
16 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
22 name
23 Every time zone has a unique name. In the zoneinfo database, these
24 are something similar to:
25
26 America/New_York
27
28 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
33 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
38 Each period includes the following information:
39
40 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 wallclock time. The
43 wallclock start time is the time that will be on a clock just as
44 the period starts (i.e. after a time change). The wallclock end
45 time is the time on a clock immediately before the period ends.
46
47 offset
48 The entire period has an offset which is how much the wallclock
49 time differs from GMT.
50
51 abbreviation
52 When expressing the time period, an abbreviation (such as EST) is
53 typically used.
54
55 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
60 Date::Manip includes all of the data for all of the time zones from the
61 zoneinfo database. This data is available from:
62
63 ftp://elsie.nci.nih.gov/pub/
64
65 Additional data from other standards are also used.
66
67 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
72 The Date::Manip::Zones document contains detailed information on the
73 data available.
74
76 In all methods, the following variables are used:
77
78 $zone
79 This is a string which contains a valid time zone name. For
80 example:
81
82 America/New_York
83
84 $alias
85 This is a strings which contains a valid time zone name, or a valid
86 time zone alias. For example:
87
88 America/New_York
89 US/Eastern
90 EST5EDT
91
92 $abbrev
93 This is a string which contains a valid time zone abbreviation. For
94 example:
95
96 EST
97
98 $offset
99 This is a time zone entered as an offset. An offset is either a
100 string of one of the formats:
101
102 +HH
103 +HHMM
104 +HHMMSS
105 +HH:MM
106 +HH:MM:SS
107
108 or it can be a list reference:
109
110 [HH,MM,SS]
111
112 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
115 [-5,-30,0]
116
117 $dstflag
118 This is always one of the values: std, stdonly, dst, dstonly
119
120 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
124 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
128 The "dst" and "dstonly" values are similar but will check daylight
129 saving times in preference.
130
131 $date
132 A date is always a string containing a date in one of the formats:
133
134 YYYYMMDDHH:MN:SS
135 YYYY-MM-DD-HH:MN:SS
136 YYYYMMDDHHMNSS
137
138 or a list reference:
139
140 [Y,M,D,H,MN,S]
141
142 $isdst
143 This is 0 if a date is in standard time, 1 if it is in daylight
144 saving time.
145
146 $period
147 A period is a list reference currently containing the following
148 items:
149
150 [ $dateUT, $dateLT, $offsetstr, $offset, $abbrev, $isdst,
151 $endUT, $endLT, $begUTs, $begLTs, $endUTs, $endLTs ]
152
153 $dateUT and $dateLT are the starting date of the period (i.e. the
154 first second in a period) in universal (GMT) time and local
155 (wallclock) time. $endUT and $endLT are the end date of the period
156 (i.e. the last second in a period) in universal and local time.
157 These are all stored as list references.
158
159 $offsetstr is the string representation of the offset ("+05:00:00")
160 and $offset is the corresponding list reference form ([5,0,0]).
161
162 $abbrev is the abbreviation that applies during this period, and
163 $isdst is 0 or 1 if it is standard or daylight saving time.
164
165 When accessing the elements in a period, use ONLY positive indices.
166 In other words, to get $endUT, access it as $$period[6], NOT as
167 $$period[-2], since I am looking at adding more information to the
168 period description that may speed up performance.
169
170 $begUTs is the string representation (YYYYMMDDHH:MN:SS) of $begUT.
171 Similar for $begLTs, $endUTs, and $endLTs.
172
173 The following methods are available:
174
175 base
176 config
177 err
178 new
179 new_config
180 Please refer to the Date::Manip::Obj documentation for these
181 methods.
182
183 all_periods
184 @periods = $tz->all_periods($zone,$year);
185
186 This returns the description of all time zone periods that occur
187 (in full or in part) during the given year.
188
189 convert
190 convert_to_gmt
191 convert_from_gmt
192 convert_to_local
193 convert_from_local
194 These functions convert a date from one time zone to another.
195
196 ($err,$date,$offset,$isdst,$abbrev) =
197 $tz->convert($date,$from,$to [,$isdst]);
198
199 This converts a date in the time zone given by $from to the time
200 zone given by $to.
201
202 ($err,$date,$offset,$isdst,$abbrev) =
203 $tz->convert_to_gmt($date [,$from] [,$isdst]);
204
205 This converts a date to GMT. If $from is given, it is the current
206 time zone of the date. If $from is omitted, it defaults to the
207 local time zone.
208
209 The value of $isdst returned is always 0.
210
211 ($err,$date,$offset,$isdst,$abbrev) =
212 $tz->convert_from_gmt($date [,$to]);
213
214 This converts a date from GMT to another time zone. If $to is
215 given, the date is converted to that time zone. Otherwise, it is
216 converted to the local time zone.
217
218 ($err,$date,$offset,$isdst,$abbrev) =
219 $tz->convert_to_local($date [,$from] [,$isdst]);
220 ($err,$date,$offset,$isdst,$abbrev) =
221 $tz->convert_from_local($date [,$to] [,$isdst]);
222
223 Similar to the convert_to_gmt and convert_from_gmt functions. If
224 $from or $to are omitted, they default to GMT.
225
226 If there is any ambiguity about whether $date is in DST or not
227 (i.e. if it is a date that is repeated during a time change due to
228 the clock being moved back), the $isdst option can be passed in as
229 an argument (it should be 0 or 1) to say which time to use. It is
230 ignored in all cases where $date can be determined without that
231 information.
232
233 The $isdst value passed back is 1 if the converted date is in DST.
234 The $offset value passed back is a list reference containing the
235 offset from GMT. $abbrev passed back is the time zone abbreviation.
236
237 Error codes are:
238
239 0 No error
240 1 Invalid arguments
241 2 Invalid FROM zone
242 3 Invalid TO zone
243 4 Invalid date
244
245 curr_zone
246 $tz->curr_zone();
247
248 This returns the system time zone. The system time zone is
249 determined using the methods described below in the DETERMINING THE
250 SYSTEM TIME ZONE section.
251
252 This is the time zone that is used by default unless the SetDate or
253 ForceDate config variable is set to a different zone.
254
255 $tz->curr_zone(1);
256
257 This clears the system time zone and re-determines it using the
258 methods described below.
259
260 The main reason to do this is if the curr_zone_methods method is
261 used to change how the time zone is determined.
262
263 curr_zone_methods
264 $tz->curr_zone_methods(@methods);
265
266 This sets the list and order of methods to use in determining the
267 local time zone. The various methods available are listed below in
268 the section DETERMINING THE SYSTEM TIME ZONE.
269
270 Some methods may require one or more arguments. For example, the
271 method named "mainvar" takes an option that is the name of a
272 variable. The arguments must be included in the @methods list
273 immediately after the method name (so @methods is actually a
274 mixture of method names and arguments).
275
276 This method may not be used in any environment where taint checking
277 is enabled. If it is, it will issue a warning, but will NOT change
278 the method list.
279
280 date_period
281 $period = $tz->date_period($date,$zone,$wallclock [,$isdst]);
282
283 This returns the period information for the given date. $date
284 defaults to GMT, but may be given as local (i.e. wallclock) time if
285 $wallclock is non-zero. The period information is described in the
286 periods method below.
287
288 If a wallclock time is given, no period is returned if the
289 wallclock time doesn't ever appear (such as when a time change
290 results in the clock moving forward "skipping" a period of time).
291 If the wallclock time appears twice (i.e. when a time change
292 results in the clock being set back), the $isdst variable is used.
293 The standard time is used unless $isdst is non-zero. $isdst is
294 ignored except in the case where there are two possible periods.
295
296 define_abbrev
297 ($err,$val) = $tz->define_abbrev($abbrev,@zone);
298
299 When encountering an abbreviation, by default, all time zones which
300 ever include the abbreviation will be examine in the order given in
301 the Date::Manip::Zones manual.
302
303 Occasionally, it may be necessary to change the order. This is true
304 if you are parsing dates in a time zone which uses an abbreviation
305 which is also used in another time zone, and where the other time
306 zone is given preference. As an example, the abbreviation "ADT"
307 will default to the "Atlantic/Bermuda" time zone. If you are in the
308 "America/Halifax" time zone (which also uses that abbreviation),
309 you may want to change the order of time zones.
310
311 This will take an abbreviation (which must be a known
312 abbreviation... there is no means of defining a totally new
313 abbreviation) and a list of zones. This will set the list of zones
314 that will be checked, and the order in which they are checked, when
315 a date is encountered with the given abbreviation. It is not
316 necessary that the list include every zone that has ever used the
317 abbreviation, but it may not include a zone that has never used it.
318
319 If $abbrev is "reset", all abbreviations are reset to the standard
320 values. If @zone includes only the element 'reset', the default
321 list for $abbrev is restored.
322
323 The following error codes are returned:
324
325 0 No error
326 1 $abbrev is not a valid abbreviation in any time zone
327 2 A zone (returned as $val) is not a valid time zone
328 3 A zone (returned as $val) does not use the abbreviation
329
330 For more information about the different zones which may correspond
331 to each abbreviation, and the order in which they will be examined
332 by default, refer to the Date::Manip::Zones manual.
333
334 define_alias
335 $err = $tz->define_alias($alias,$zone);
336
337 This will define a new alias (or override an existing alias). $zone
338 must be a valid zone or an error is returned.
339
340 For more information about the different aliases which are set by
341 default, refer to the Date::Manip::Zones manual.
342
343 If $alias is "reset", all aliases will be reset to the standard
344 values. If $zone is "reset", $alias will be reset to the standard
345 value.
346
347 define_offset
348 ($err,$val) = $tz->define_offset($offset, [$dstflag,] @zone);
349
350 This is similar to the define_abbrev method. When an offset is
351 encountered, all time zones which have ever included that offset
352 are checked. This will defined which time zones, and in what order,
353 they should be checked.
354
355 The zones to both standard and daylight saving times which include
356 the offset (if $dstflag is "std" or "dst") or to only one or the
357 other.
358
359 If $offset is "reset", all lists are reset to the default values.
360 If @zone includes only the element 'reset', the default list and
361 order is restored for $offset ($dstflag must not be given).
362
363 The following error codes are returned:
364
365 0 No error
366 1 $offset is not a valid offset in any time zone
367 2 $offset is not a valid offset in the selected
368 time (if doing "dstonly" or "stdonly")
369 3 A zone (returned as $val) is not a valid time zone
370 4 A zone (returned as $val) does not use the offset
371 5 A zone (returned as $val) does not include the
372 offset in the selected time (if doing "dstonly"
373 or "stdonly")
374
375 9 Offset is not a valid offset
376
377 periods
378 @periods = $tz->periods($zone,$year);
379
380 This returns the description of all time zone periods that begin
381 during the year given. The year is measured in universal (GMT)
382 time.
383
384 If no time zone period starts in the given year, nothing is
385 returned.
386
387 @periods = $tz->periods($zone,undef,$year);
388
389 This returns all periods that begin in any year from 0001 to $year.
390
391 @periods = $tz->periods($zone,$year0,$year1);
392
393 This returns all periods that begin in any year from $year0 to
394 $year1.
395
396 tzdata
397 tzcode
398 $vers = $tz->tzdata();
399 $vers = $tz->tzcode();
400
401 These return the versions of the tzdata and tzcode packages used to
402 generate the modules.
403
404 zone
405 $zone = $tz->zone(@args);
406 @zone = $tz->zone(@args);
407
408 This function will return a list of all zones, or the default zone,
409 which matches all of the supplied information. In scalar context,
410 it will return only the default zone. In list context, it will
411 return all zones.
412
413 @args may include any of the following items, and the order is not
414 important.
415
416 A zone name or alias ($alias)
417
418 A zone abbreviation ($abbrev)
419
420 An offset ($offset)
421
422 A dstflag ($dstflag)
423
424 A date ($date)
425
426 It is NOT valid to include two of any of the items. Any time zone
427 returned will match all of the data supplied.
428
429 If an error occurs, undef is returned. If no zone matches, an empty
430 string, or an empty list is returned.
431
432 The order of the zones will be determined in the following way:
433
434 If $abbrev is given, the order of time zones will be determined by
435 it (and $dstflag). If $dstflag is "std", all zones which match
436 $abbrev in standard time are included, followed by all that match
437 $abbrev in saving time (but no duplication is allowed). The reverse
438 is true if $dstflag is "dst".
439
440 If $abbrev is not given, but $offset is, $offset (and $dstflag)
441 will determine the order given. If $dstflag is "std", all zones
442 which match $offset in standard time are included, followed by all
443 that match $offset in saving time (but no duplication is allowed).
444 The reverse is true if $dstflag is "dst".
445
446 If $date is given, only zones in which $date will appear in a zone
447 that matches all other information are given. $date is a wallclock
448 time.
449
450 If no $zone, $abbrev, or $offset are entered, the local time zone
451 may be returned (unless $date is entered, and it doesn't exist in
452 the local time zone).
453
454 NOTE: there is one important thing to note with respect to $dstflag
455 when you are working with a timezone expressed as an offset and a
456 date is passed in. In this case, the default value of $dstflag is
457 "dst" (NOT "stdonly"), and you probably never want to pass in a
458 value of "std" (though passing in "stdonly" is okay).
459
460 For standard offsets (with no minute component), there is always a
461 standard timezone which matches that offset. For example, the
462 timezone "+0100" matches the timezone "Etc/GMT+01", so you will
463 never get a timezone in daylight saving time if $dstflag is "std".
464
465 If you want to pass in a date of 2001-07-01-00:00:00 and an
466 timezone of "+0100" and you want to get a timezone that refers to
467 that date as a daylight saving time date, you must use the $dstflag
468 of "dst" (or "dstonly").
469
470 Because this is almost always the behavior desired, when a zone is
471 passed in as an offset, and a date is passed in, the default
472 $dstflag is "dst" instead of "std". In all other situations, the
473 default is still "std".
474
475 If the timezone is expressed as an abbreviation, this problem does
476 not occur.
477
479 Date::Manip makes use of three potentially different time zones when
480 working with a date.
481
482 The first time zone that may be used is the actual local time zone.
483 This is the time zone that the computer is actually running in.
484
485 The second time zone is the working time zone. Usually, you will want
486 the default time zone to be the local time zone, but occasionally, you
487 may want the default time zone to be different.
488
489 The third time zone is the actual time zone that was parsed, or set,
490 for a date. If a date contains no time zone information, it will
491 default to the working time zone.
492
493 The local time zone is determined using the methods described in the
494 following section. The preferred way is to locate the time zone in some
495 system file, or using some system command, or (in the case of a Windows
496 operating system) to look it up in the registry. If all of these
497 methods fail, the local time zone may be set using either the $::TZ or
498 $ENV{TZ} variables. Please note that these should ONLY be used to set
499 the actual local time zone.
500
501 If you are running in one time zone, but you want to force dates to be
502 specified in an alternate time zone by default, you need to set the
503 working time zone. The working time zone defaults to the local time
504 zone, but this can be changed using either the SetDate or ForceDate
505 config variables. Refer to the Date::Manip::Config manual for more
506 information.
507
508 Finally, when a date is actually parsed, if it contains any time zone
509 information, the date is stored in that time zone.
510
512 There are a large number of ways available for determining the time
513 zone. Some or all of them may be checked. A list of methods to use is
514 provided by default, and may be overridden by the curr_zone_methods
515 function described above. To override the default order and/or list of
516 methods, just pass in a list of method names (with arguments where
517 necessary), and only those methods will be done, and in the order
518 given.
519
520 The following methods are available:
521
522 Method Argument(s) Procedure
523 ====== =========== =========
524
525 main VAR The main variable named VAR is
526 checked. E.g. "main TZ" checks
527 the variable $::TZ .
528
529 env TYPE VAR The named environment variable
530 is checked and the type of
531 data stored there (TYPE can
532 be 'zone' or 'offset' which
533 is the number of seconds from
534 UTC).
535
536 file FILE Look in the given file for any
537 one of the following case
538 insensitive lines:
539 ZONE
540 tz = ZONE
541 zone = ZONE
542 timezone = ZONE
543 ZONE may be quoted (single or
544 double) and whitespace is
545 ignored. If the entire line
546 is a zone, it must be the first
547 non-blank non-comment line in
548 the file.
549
550 command COMMAND Runs a command which produces
551 a time zone as the output.
552
553 cmdfield COMMAND N Runs a command which produces
554 whitespace separated fields,
555 the Nth one containing the
556 time zone (fields are numbered
557 starting at 0, or from the
558 end starting at -1).
559
560 gmtoff Uses the current offset from
561 GMT to come up with a best guess.
562
563 registry Look up the value in the
564 Windows registry. This is only
565 available to hosts running a
566 Windows operating system.
567
568 Note that the "main" and "env" methods should only be used to specify
569 the actual time zone the system is running in. Use the SetDate and
570 ForceDate config variables to specify an alternate time zone that you
571 want to work in.
572
573 By default, the following methods are checked (in the order given) on
574 Unix systems:
575
576 main TZ
577 env zone TZ
578 file /etc/TIMEZONE
579 file /etc/timezone
580 file /etc/sysconfig/clock
581 file /etc/default/init
582 command "/bin/date +%Z"
583 command "/usr/bin/date +%Z"
584 command "/usr/local/bin/date +%Z"
585 cmdfield /bin/date -2
586 cmdfield /usr/bin/date -2
587 cmdfield /usr/local/bin/date -2
588 gmtoff
589
590 The default methods for Windows systems are:
591
592 main TZ
593 env zone TZ
594 registry
595 gmtoff
596
597 The default methods for VMS systems are:
598
599 main TZ
600 env zone TZ
601 env zone SYS$TIMEZONE_NAME
602 env zone UCX$TZ
603 env zone TCPIP$TZ
604 env zone MULTINET_TIMEZONE
605 env offset SYS$TIMEZONE_DIFFERENTIAL
606 gmtoff
607
608 The default methods for all other systems are:
609
610 main TZ
611 env zone TZ
612 gmtoff
613
614 If anyone wants better support for a specific OS, please contact me and
615 we'll coordinate adding it.
616
617 In all cases, the value returned from the method may be any of the
618 following:
619
620 the full name of a time zone (e.g. America/New_York)
621 or an alias
622
623 an abbreviation (e.g. EDT) which will be used to
624 determine the zone if possible
625
626 an offset (+hh, +hhmn, +hh:mm, +hh:mm:ss) from GMT
627
628 The Date::Manip::Zones module contains information about the time zones
629 and aliases available, and what time zones contain the abbreviations.
630
632 The design decisions made in writing this module may cause some
633 questions (and probably complaints). The time zone modules are all
634 generated using scripts (included in the Date::Manip distribution)
635 which use the standard tzdata tools to parse the tzdata files and store
636 that information in perl modules.
637
638 I'd like to address some of them, to avoid answering some of the "why
639 did you do it that way" remarks. I do welcome discussion about these
640 decisions... but preferably after you understand why those decisions
641 were made so that that we have an informed basis to begin a discussion.
642
643 Why not use existing zoneinfo files
644 Some people will probably think that I should have written an
645 interface to the zoneinfo files which are distributed with most
646 operating systems. Although I considered doing that, I rejected
647 the idea for two reasons.
648
649 First, not all operating systems come with the zoneinfo databases
650 in a user accessible state (Micro$oft for example). Even those
651 that do include them store the information in various formats and
652 locations. In order to bypass all that, I have included the data
653 directly in these modules.
654
655 Second, as I was doing my initial investigations into this, I ran
656 into a bug in the Solaris zoneinfo tools (long since fixed I'm
657 sure). I decided then that I didn't want to depend on an
658 implementation where I could not control and fix the bugs.
659
660 Why not use the native tzdata files
661 Another decision people may question is that I parse the tzdata
662 files and store the data from them in a large number of perl
663 modules instead of creating an interface to the tzdata files
664 directly. This was done solely for the sake of speed. Date::Manip
665 is already a slow module. I didn't want to slow it down further by
666 doing the complex parsing required to interpret the tzdata files
667 while manipulating dates. By storing the data in these modules,
668 there is little or no parsing done while using Date::Manip modules.
669 It costs a little disk space to store this information... but very
670 little of it is actually loaded at runtime (time zone data is only
671 loaded when the time zone is actually referred to), so I feel it's
672 a good tradeoff.
673
674 Why store the information in so many files
675 The data from the native tzdata files are parsed and stored in two
676 sets of modules. These include almost 500 Date::Manip::Offset::*
677 modules and almost 450 Date::Manip::TZ::* modules.
678
679 I note that on my linux box, /usr/share/zoneinfo (which contains
680 data files generated from the tzdata files) contains over 1700
681 files, so I'm not doing anything "new" by breaking up the
682 information into separate files. And doing so has a huge impact on
683 performance... it is not necessary to load and/or manipulate data
684 from time zones which are not in use.
685
686 The minute I made the decision to distribute the timezone
687 information myself, as opposed to using the system version, it was
688 a given that there would be a lot of files.
689
690 These modules are loaded only when the time zone or offset is
691 actually used, so, unless dates from around the world are being
692 parsed, only a very small number of these modules will actually be
693 loaded. In many applications, only a single TZ module will be
694 loaded. If parsing dates which have timezone information stored as
695 offsets, one or two Offset modules will also be loaded.
696
697 The disk space seems excessive
698 Currently, the disk usage of the perl files is around 9 MB. Total
699 disk usage for /usr/share/zoneinfo on my computer is around 4 MB.
700 There are a couple of differences.
701
702 The primary difference is that the zoneinfo files are stored in a
703 binary (and hence, more compressed) version, where the perl modules
704 have all the data in pure text.
705
706 Since these are all automatically generated and used, it may be
707 beneficial to store the data in some packed binary format instead
708 of the fully expanded text form that is currently in use. This
709 would decrease the disk space usage, and might improve performance.
710 However, the performance improvement would happen only once per
711 timezone, and would make for more complicated code, so I'm not very
712 interested in pursuing this.
713
714 Another aspect of the current modules is that they all include pod
715 documentation. Although not necessary, this allows users to easily
716 see what modules handle which time zones, and that's nice. It also
717 allows me to use pod_coverage tests for the module which is a nice
718 check to make sure that the documentation is accurate.
719
720 All told, I don't consider the disk usage excessive at all.
721
723 Unable to determine Time Zone
724 When using Date::Manip, when the module is initialized, it must be
725 able to determine the local time zone. If it fails to do so, an
726 error will occur:
727
728 Unable to determine Time Zone
729
730 and the script will exit.
731
732 In the past, this was the most common problem with using
733 Date::Manip . With the release of 6.00, this problem should be
734 significantly less common. If you do get this error, please refer
735 to the section above DETERMINING THE SYSTEM TIME ZONE for
736 information about determining the local time zone. I am also
737 interested in hearing about this so that I can update the default
738 list of methods to be able to determine the local time zone better.
739
740 Asia/Jerusalem time zone
741 The Asia/Jerusalem time zone has a non-standard way of specifying
742 the start and end of Daylight Saving Time based on the Hebrew
743 calendar.
744
745 As a result, there is no way to specify a simple rule to define
746 time zone changes for all years in the future. As such, this module
747 supports all time zone changes currently specified in the zoneinfo
748 database (which currently goes to the year 2037) but does not
749 attempt to correctly handle zone changes beyond that date. As a
750 result, Date::Manip should not be used to parse dates in the
751 Jerusalem time zone that are far enough in the future that
752 information is not included in the current version of the zoneinfo
753 database.
754
755 LMT and zzz abbreviations
756 Both the LMT and zzz abbreviations are used in the zoneinfo
757 databases. LMT is use for most time zones for the times before the
758 Gregorian calendar was adopted, and zzz is used for a few where the
759 time zone was created and no description of dates prior to that are
760 supported. Both LMT and zzz are basically ignored in parsing dates
761 (because there is no reasonable way to determine which zone they
762 are referring to), and will be treated as the local time zone
763 regardless.
764
766 None known.
767
769 Please refer to the Date::Manip::Problems documentation for information
770 on submitting bug reports or questions to the author.
771
773 Date::Manip - main module documentation
774
776 This script is free software; you can redistribute it and/or modify it
777 under the same terms as Perl itself.
778
780 Sullivan Beck (sbeck@cpan.org)
781
782
783
784perl v5.10.1 2011-12-07 Date::Manip::TZ(3)