diff options
Diffstat (limited to 'zic.8')
| -rw-r--r-- | zic.8 | 47 |
1 files changed, 40 insertions, 7 deletions
@@ -63,7 +63,7 @@ Link \fItimezone\fP localtime Use .IR timezone 's rules when handling POSIX-format -timezone environment variables. +TZ strings like "CST6CDT" that lack transition rules. .B zic will act as if the input contained a link line of the form .sp @@ -79,6 +79,30 @@ Read leap second information from the file with the given name. If this option is not used, no leap second information appears in output files. .TP +.BR "\*-r " "[\fB@\fP\fIlo\fP][\fB/@\fP\fIhi\fP]" +Reduce the size of output files by limiting their applicability +to timestamps in the range from +.I lo +(inclusive) to +.I hi +(exclusive), where +.I lo +and +.I hi +are possibly-signed decimal counts of seconds since the Epoch +(1970-01-01 00:00:00 UTC). +Omitted counts default to extreme values. +For example, +.q "zic \*-r @0" +omits data intended for negative timestamps (i.e., before the Epoch), and +.q "zic \*-r @0/@2147483648" +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)" +omits data intended for past timestamps. +.TP .B \*-v Be more verbose, and complain about the following situations: .RS @@ -102,7 +126,7 @@ prohibit this. .PP The output file does not contain all the information about the long-term future of a timezone, because the future cannot be summarized as -an extended POSIX TZ string. For example, as of 2013 this problem +an extended POSIX TZ string. For example, as of 2019 this problem occurs for Iran's daylight-saving rules for the predicted future, as these rules are based on the Iranian calendar, which cannot be represented. @@ -125,11 +149,10 @@ or it contains a file name component that contains more than 14 bytes or that starts with .q "\*-" . .RE -.TP -.B \*-s -Limit time values stored in output files to values that are the same -whether they're taken to be signed or unsigned. -You can use this option to generate SVVS-compatible files. +.SH FILES +Input files use the format described in this section; output files use +.IR tzfile (5) +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 @@ -457,6 +480,16 @@ continuation. .PP If a zone changes at the same instant that a rule would otherwise take effect in the earlier zone or continuation line, the rule is ignored. +A zone or continuation line +.I L +with a named rule set starts with standard time by default: +that is, any of +.IR L 's +timestamps preceding +.IR L 's +earliest rule use the rule in effect after +.IR L 's +first transition into standard time. In a single zone it is an error if two rules take effect at the same instant, or if two zone changes take effect at the same instant. .PP |