diff options
Diffstat (limited to 'zic.8')
| -rw-r--r-- | zic.8 | 57 |
1 files changed, 42 insertions, 15 deletions
@@ -28,6 +28,16 @@ zic \- timezone compiler . ds : . ds - \- .\} +.ds d " degrees +.ds m " minutes +.ds s " seconds +.ds _ " \" +.if t .if \n(.g .if c \(de .if c \(fm .if c \(sd \{\ +. ds d \(de +. ds m \(fm +. ds s \(sd +. ds _ \| +.\} The .B zic program reads text from the file(s) named on the command line @@ -136,8 +146,7 @@ are possibly-signed decimal counts of seconds since the Epoch Omitted counts default to extreme values. The output files use UT offset 0 and abbreviation .q "\*-00" -in place of the omitted timestamp data; -this typically reduces the files' sizes. +in place of the omitted timestamp data. For example, .q "zic \*-r @0" omits data intended for negative timestamps (i.e., before the Epoch), and @@ -146,12 +155,31 @@ outputs data intended only for nonnegative timestamps that fit into 31-bit signed integers. On platforms with GNU .BR date , -.q "zic \-r @$(date +%s)" +.q "zic \*-r @$(date +%s)" omits data intended for past timestamps. +Although this option typically reduces the output file's size, +the size can increase due to the need to represent the timestamp range +boundaries, particularly if +.I hi +causes a TZif file to contain explicit entries for +.RI pre- hi +transitions rather than concisely representing them +with an extended POSIX TZ string. Also see the .B "\*-b slim" option for another way to shrink output size. .TP +.BI "\*-R @" hi +Generate redundant trailing explicit transitions for timestamps +that occur less than +.I hi +seconds since the Epoch, even though the transitions could be +more concisely represented via the extended POSIX TZ string. +This option does not affect the represented timestamps. +Although it accommodates nonstandard TZif readers +that ignore the extended POSIX TZ string, +it increases the size of the altered output files. +.TP .BI "\*-t " file When creating local time information, put the configuration link in the named file rather than in the standard location. @@ -253,7 +281,8 @@ format. .PP Input files should be text files, that is, they should be a series of zero or more lines, each ending in a newline byte and containing at -most 511 bytes, and without any NUL bytes. The input text's encoding +most 2048 bytes counting the newline, and without any NUL bytes. +The input text's encoding is typically UTF-8 or ASCII; it should have a unibyte representation for the POSIX Portable Character Set (PPCS) \*<https://pubs\*:.opengroup\*:.org/\*:onlinepubs/\*:9699919799/\*:basedefs/\*:V1_chap06\*:.html\*> @@ -521,7 +550,7 @@ This field has the same format as the .B AT and .B SAVE -fields of rule lines; +fields of rule lines, except without suffix letters; begin the field with a minus sign if time must be subtracted from UT. .TP .B RULES @@ -749,15 +778,13 @@ The .BR DAY , and .B HH:MM:SS -fields give the expiration timestamp in UTC for the leap second table; +fields give the expiration timestamp in UTC for the leap second table. +.br +.ne 22 .SH "EXTENDED EXAMPLE" Here is an extended example of .B zic input, intended to illustrate many of its features. -In this example, the EU rules are for the European Union -and for its predecessor organization, the European Communities. -.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'\*-\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00\0\0'u +\w'SAVE\0\0'u @@ -784,13 +811,13 @@ Link Europe/Zurich Europe/Vaduz .sp .in .fi -In this example, the timezone is named Europe/Zurich but it has an alias -as Europe/Vaduz. This example says that Zurich was 34 minutes and 8 +In this example, the EU rules are for the European Union +and for its predecessor organization, the European Communities. +The timezone is named Europe/Zurich and it has the alias Europe/Vaduz. +This example says that Zurich was 34 minutes and 8 seconds east of UT until 1853-07-16 at 00:00, when the legal offset was changed to -.ds o 7 degrees 26 minutes 22.50 seconds -.if \n(.g .if c \(de .if c \(fm .if c \(sd .ds o 7\(de\|26\(fm\|22.50\(sd -\*o, +7\*d\*_26\*m\*_22.50\*s, which works out to 0:29:45.50; .B zic treats this by rounding it to 0:29:46. |