diff options
Diffstat (limited to 'zic/zic.8')
| -rw-r--r-- | zic/zic.8 | 91 |
1 files changed, 80 insertions, 11 deletions
diff --git a/zic/zic.8 b/zic/zic.8 index 86b13544f971..f842927a7b7e 100644 --- a/zic/zic.8 +++ b/zic/zic.8 @@ -269,7 +269,7 @@ A zone line has the form .nf .ti +.5i .ta \w'Zone\0\0'u +\w'Australia/Adelaide\0\0'u +\w'GMTOFF\0\0'u +\w'RULES/SAVE\0\0'u +\w'FORMAT\0\0'u -Zone NAME GMTOFF RULES/SAVE FORMAT [UNTIL] +Zone NAME GMTOFF RULES/SAVE FORMAT [UNTILYEAR [MONTH [DAY [TIME]]]] .sp For example: .sp @@ -311,15 +311,15 @@ Alternately, a slash (/) separates standard and daylight abbreviations. .TP -.B UNTIL +.B UNTILYEAR [MONTH [DAY [TIME]]] The time at which the UTC offset or the rule(s) change for a location. It is specified as a year, a month, a day, and a time of day. If this is specified, the time zone information is generated from the given UTC offset and rule change until the time specified. The month, day, and time of day have the same format as the IN, ON, and AT -columns of a rule; trailing columns can be omitted, and default to the -earliest possible value for the missing columns. +fields of a rule; trailing fields can be omitted, and default to the +earliest possible value for the missing fields. .IP The next line must be a .q continuation @@ -328,11 +328,11 @@ string .q Zone and the name are omitted, as the continuation line will place information starting at the time specified as the -.B UNTIL -field in the previous line in the file used by the previous line. -Continuation lines may contain an -.B UNTIL -field, just as zone lines do, indicating that the next line is a further +.q until +information in the previous line in the file used by the previous line. +Continuation lines may contain +.q until +information, just as zone lines do, indicating that the next line is a further continuation. .PP A link line has the form @@ -411,14 +411,83 @@ or .q Rolling if the leap second time given by the other fields should be interpreted as local wall clock time. -.SH NOTE +.SH "EXTENDED EXAMPLE" +Here is an extended example of +.I zic +input, intended to illustrate many of its features. +.br +.ne 22 +.nf +.in +2m +.ta \w'# Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'TYPE\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00\0\0'u +\w'SAVE\0\0'u +.sp +# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S +Rule Swiss 1940 only - Nov 2 0:00 1:00 S +Rule Swiss 1940 only - Dec 31 0:00 0 - +Rule Swiss 1941 1942 - May Sun>=1 2:00 1:00 S +Rule Swiss 1941 1942 - Oct Sun>=1 0:00 0 +.sp .5 +Rule EU 1977 1980 - Apr Sun>=1 1:00u 1:00 S +Rule EU 1977 only - Sep lastSun 1:00u 0 - +Rule EU 1978 only - Oct 1 1:00u 0 - +Rule EU 1979 1995 - Sep lastSun 1:00u 0 - +Rule EU 1981 max - Mar lastSun 1:00u 1:00 S +Rule EU 1996 max - Oct lastSun 1:00u 0 - +.sp +.ta \w'# Zone\0\0'u +\w'Europe/Zurich\0\0'u +\w'0:34:08\0\0'u +\w'RULES/SAVE\0\0'u +\w'FORMAT\0\0'u +# Zone NAME GMTOFF RULES FORMAT UNTIL +Zone Europe/Zurich 0:34:08 - LMT 1848 Sep 12 + 0:29:44 - BMT 1894 Jun + 1:00 Swiss CE%sT 1981 + 1:00 EU CE%sT +.sp +Link Europe/Zurich Switzerland +.sp +.in +.fi +In this example, the zone is named Europe/Zurich but it has an alias +as Switzerland. Zurich was 34 minutes and 8 seconds west of GMT until +1848-09-12 at 00:00, when the offset changed to 29 minutes and 44 +seconds. After 1894-06-01 at 00:00 Swiss daylight saving rules (defined +with lines beginning with "Rule Swiss") apply, and the GMT offset +became one hour. From 1981 to the present, EU daylight saving rules have +applied, and the UTC offset has remained at one hour. +.PP +In 1940, daylight saving time applied from November 2 at 00:00 to +December 31 at 00:00. In 1941 and 1942, daylight saving time applied +from the first Sunday in May at 02:00 to the first Sunday in October +at 00:00. +The pre-1981 EU daylight-saving rules have no effect +here, but are included for completeness. Since 1981, daylight +saving has begun on the last Sunday in March at 01:00 UTC. +Until 1995 it ended the last Sunday in September at 01:00 UTC, +but this changed to the last Sunday in October starting in 1996. +.PP +For purposes of +display, "LMT" and "BMT" were initially used, respectively. Since +Swiss rules and later EU rules were applied, the display name for the +timezone has been CET for standard time and CEST for daylight saving +time. +.SH NOTES For areas with more than two types of local time, you may need to use local standard time in the .B AT field of the earliest transition time's rule to ensure that the earliest transition time recorded in the compiled file is correct. +.PP +If, +for a particular zone, +a clock advance caused by the start of daylight saving +coincides with and is equal to +a clock retreat caused by a change in UTC offset, +.IR zic +produces a single transition to daylight saving at the new UTC offset +(without any change in wall clock time). +To get separate transitions +use multiple zone continuation lines +specifying transition instants using universal time. .SH FILE /usr/local/etc/zoneinfo standard directory used for created files .SH "SEE ALSO" newctime(3), tzfile(5), zdump(8) -.\" @(#)zic.8 7.22 +.\" @(#)zic.8 8.4 |