加载中…POSIX1003.1 时区字符串格式
(2013-01-16 18:02:31)
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时区字符串格式
示例：
is
the designation for the time zone (in this case Hawaii Standard
Time) and is
the offset in hours. The offset indicates the value one must add to
the local time to arrive at Coordinated Universal Time (UTC, aka
GMT), and so it is positive for west of the meridian, e.g. America,
and negative for east, e.g. China.
and mean
the same thing. Note that the sign convention (+/-) used in a Posix
TZ string is the opposite to
that used in Internet time offsets ( RFC
3339)
and in =
designation for standard time when daylight saving is not in
force
=
offset in hours = 5 hours west of Greenwich meridian (i.e. behind
UTC)
=
designation when daylight saving is in force (if omitted there is
no daylight saving)
=
no offset number between code and comma, so default to one hour
ahead for daylight saving
=
when daylight saving starts = the 0th day (Sunday) in the second
week of month 3 (March)
=
the local time
when the switch occurs = 2 a.m. in this
case
=
when daylight saving ends = the 0th day (Sunday) in the first week
of month 11 (November). No time is given here so the switch occurs
at 02:00 local time.
=
designation for standard time when daylight saving is not in
force
=
offset in hours = negative so 1 hour east of Greenwich
meridian
=
designation when daylight saving is in force ("Central European
Summer Time")
=
no offset number between code and comma, so default to one hour
ahead for daylight saving
=
when daylight saving starts = the last Sunday in March (the "5th"
week means the last in the month)
=
the local time
when the switch occurs = 2 a.m. in this
case
=
when daylight saving ends = the last Sunday in
October.
=
the local time
when the switch occurs = 3 a.m. in this
case
[continent/city] TZ=posix-tz-stringTime zones that do not have daylight savings have a simple TZ string, e.g.
[Pacific/Honolulu] TZ=HST10Where
HST 10 [Asia/Beijing] TZ=CST-8Minutes and seconds are optional, so
CST-8 CST-08:00:00 Let's examine the TZ string for a city with daylight saving time
[America/New_York] TZ=EST5EDT,M3.2.0/2,M11.1.0
EST
5
EDT
,
M3.2.0
/2,
M11.1.0
So daylight saving starts on the second sunday in March and
finishes on the first Sunday in November. The switch occurs at
02:00 local time in both cases. This is the default switch time, so
the /2
[Europe/Paris] TZ=CET-1CEST,M3.5.0/2,M10.5.0/3
CET
-1
CEST
,
M3.5.0
/2,
M10.5.0
/3, The European Union time zones are arranged so the switch takes place at the same time in all zones.
[America/St_Johns] TZ=NST03:30NDT,M3.2.0/0:01,M11.1.0/0:01Newfoundland's standard time is three and a half hours behind UTC with daylight saving beginning on the second Sunday in March and ending on the first Sunday in November, but the switch occurs at one minute past midnight local time.
As an extreme example, consider the mythical city of Foobar in Atlantis.
[Atlantis/Foobar] TZ=AST2:45ADT0:45,M4.1.6/1:45,M10.5.6/2:45Atlantis Standard Time (AST) is 2 hours 45 minutes behind UTC and for daylight saving (ADT) they put their clocks forward two hours (i.e. to be 45 minutes behind UTC). Daylight saving starts on the first Saturday in April with the switch happening at 01:45 in the morning, and daylight saving ends on the last Saturday in October with the switch at 02:45 local time.
格式
=================================================================================
TZ Timezone information. TZ has the form:
stdoffset[dst[offset],[start[/time],end[/time]]]
std and dst
Three or more bytes that are the designation for
the standard (std) and daylight savings time
(dst) timezones. Only std is required. If dst
is missing, then daylight savings time does not
apply in this locale. Upper- and lower-case
letters are allowed. Any characters except a
leading colon (:), digits, a comma (,), a minus
(-) or a plus (+) are allowed.
offset
Indicates the value one must add to the local
time to arrive at Coordinated Universal Time.
The offset has the form:
hh[:mm[:ss]]
The minutes (mm) and seconds (ss) are optional.
The hour (hh) is required and may be a single
digit. The offset following std is required.
If no offset follows dst , daylight savings time
is assumed to be one hour ahead of standard
time. One or more digits may be used; the value
is always interpreted as a decimal number. The
hour must be between 0 and 24, and the minutes
(and seconds) if present between 0 and 59. Out
of range values may cause unpredictable
behavior. If preceded by a "-" the timezone is
east of the Prime Meridian; otherwise it is west
(which may be indicated by an optional preceding
"+" sign).
start/time,end/time
Indicate when to change to and back from day-
light savings time, where start/time describes
when the change from standard time to daylight
savings time occurs, and end/time describes when
the change back happens. Each time field
describes when, in current local time, the
change is made.
The formats of start and end are one of the fol-
lowing:
Jn The Julian day n (1 < n < 365). Leap days
are not counted. That is, in all years,
February 28 is day 59 and March 1 is day
60. It is impossible to refer to the
occasional February 29.
n The zero-based Julian day (0 < n < 365).
Leap days are counted, and it is possible
to refer to February 29.
Mm.n.d
The d**th day, (0 < d < 6) of week n of
month m of the year (1 < n < 5, 1 < m <
12), where week 5 means "the last d-day in
month m" which may occur in either the
fourth or the fifth week). Week 1 is the
first week in which the d**th day occurs.
Day zero is Sunday.
Implementation specific defaults are used for start
and end if these optional fields are not given.
The time has the same format as offset except
that no leading sign ("-" or "+" is allowed. The
default, if time is not given is 02:00:00.
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