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Diff for /src/lib/libc/time/zdump.8 between version 1.14 and 1.14.2.1

version 1.14, 2014/10/23 18:45:58 version 1.14.2.1, 2016/11/04 14:48:53
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 .\"     $NetBSD$  .\"     $NetBSD$
 .Dd October 23, 2014  .Dd October 6, 2016
 .Dt ZDUMP 8  .Dt ZDUMP 8
 .Os  .Os
 .Sh NAME  .Sh NAME
Line 26  These options are available:
Line 26  These options are available:
 .Bl -tag -width XXXXXXXXX -compact  .Bl -tag -width XXXXXXXXX -compact
 .It Fl \-version  .It Fl \-version
 Output version information and exit.  Output version information and exit.
   .It Fl i
   .Em This option is experimental: its behavior may change in future versions.
   Output a description of time intervals.
   For each
   .Ar zonename
   on the command line, output an interval-format description of the
   zone.
   See
   .Sx "INTERVAL FORMAT"
   below.
 .It Fl v  .It Fl v
   Output a verbose description of time intervals.
 For each  For each
 .Ar zonename  .Ar zonename
 on the command line,  on the command line,
Line 37  each detected time discontinuity,
Line 48  each detected time discontinuity,
 the time at one day less than the highest possible time value,  the time at one day less than the highest possible time value,
 and the time at the highest possible time value.  and the time at the highest possible time value.
 Each line is followed by  Each line is followed by
 .Dl isdst= D  .Em isdst=D
 where  where
 .Dl D  .Em D
 is positive, zero, or negative depending on whether  is positive, zero, or negative depending on whether
 the given time is daylight saving time, standard time,  the given time is daylight saving time, standard time,
 or an unknown time type, respectively.  or an unknown time type, respectively.
 Each line is also followed by  Each line is also followed by
 .Dl gmtoff= N  .Em gmtoff=N
 if the given local time is known to be  if the given local time is known to be
 .D N  .Em N
 seconds east of Greenwich.  seconds east of Greenwich.
 .It Fl c Ar [loyear,]highyear  .It Fl c Ar [loyear,]highyear
 Cut off verbose output at the given year(s).  Cut off interval output at the given year(s).
 Cutoff times are computed using the proleptic Gregorian calendar with year 0  Cutoff times are computed using the proleptic Gregorian calendar with year 0
 and with Universal Time (UT) ignoring leap seconds.  and with Universal Time (UT) ignoring leap seconds.
 The lower bound is exclusive and the upper is inclusive; for example, a  The lower bound is exclusive and the upper is inclusive; for example, a
 .Dl loyear  .Em loyear
 of 1970 excludes a transition occurring at 1970-01-01 00:00:00 UTC but a  of 1970 excludes a transition occurring at 1970-01-01 00:00:00 UTC but a
 .Dl hiyear  .Em hiyear
 of 1970 includes the transition.  of 1970 includes the transition.
 The default cutoff is  The default cutoff is
 .Dl \*-500,2500 .  .Em \&-500,2500 .
 .It Fl t Ar [lotime,]hightime  .It Fl t Ar [lotime,]hightime
 Cut off verbose output at the given time(s),  Cut off interval output at the given time(s),
 given in decimal seconds since 1970-01-01 00:00:00  given in decimal seconds since 1970-01-01 00:00:00
 Coordinated Universal Time (UTC).  Coordinated Universal Time (UTC).
 The  The
Line 76  except omit the times relative to the ex
Line 87  except omit the times relative to the ex
 This generates output that is easier to compare to that of  This generates output that is easier to compare to that of
 implementations with different time representations.  implementations with different time representations.
 .El  .El
   .Sh "INTERVAL FORMAT"
   .Em This format is experimental: it may change in future versions.
   .Pp
   The interval format is a compact text representation that is intended
   to be both human- and machine-readable.
   It consists of an empty line, then a line
   .Dq TZ=string
   where
   .Dv string
   is a double-quoted string giving the zone name, a second line
   .Dq \&- \&- interval
   describing the time interval before the first transition if any, and
   zero or more following lines
   .Dq date time interval
   one line for each transition time and following interval.
   Fields are separated by single tabs.
   .Pp
   Dates are in
   .Dv yyyy-mm-dd
   format and times are in 24-hour
   .Dv hh:mm:ss
   format where
   .Dv hh \*[Lt] 24 .
   Times are in local time immediately after the transition.
   A time interval description consists of a UT offset in signed
   .Dv \&+- hh : mm : ss
   format, a time zone abbreviation, and an isdst flag.
   An abbreviation that equals the UT offset is omitted; other abbreviations are
   double-quoted strings unless they consist of one or more alphabetic
   characters.
   An isdst flag is omitted for standard time, and otherwise
   is a decimal integer that is unsigned and positive (typically 1) for
   daylight saving time and negative for unknown.
   .Pp
   In times and UT offsets, the seconds are omitted if they are zero, and
   the minutes are also omitted if they are also zero.
   Positive UT offsets are east of Greenwich.  The UT offset \&-00 denotes a UT
   placeholder in areas where the actual offset is unspecified; by
   convention, this occurs when the UT offset is zero and the time zone
   abbreviation begins with
   .Dq \&-
   or is
   .Dq zzz .
   .Pp
   In double-quoted strings, escape sequences represent unusual
   characters.  The escape sequences are \es for space, and \e", \e\e,
   \ef, \en, \er, \et, and \ev with their usual meaning in the C
   programming language.
   E.g., the double-quoted string
   .Sq "CET\es\e"\e\e"
   represents the character sequence
   .Sq CET
   .Pp
   Here is an example of the output, with the leading empty line omitted.
   (This example is shown with tab stops set far enough apart so that the
   tabbed columns line up.)
   .Bd -literal
   TZ="Pacific/Honolulu"
   .Ed
   .Bl -column "XXXX-XX-XX" "HH:MM:SS" "-HH:MM:SS" "TZT" "X" -compact
   .It - Ta - Ta -10:31:26 Ta LMT Ta
   .It 1896-01-13 Ta 12:01:26 Ta -10:30 Ta HST Ta
   .It 1933-04-30 Ta 03 Ta -09:30 Ta HDT Ta 1
   .It 1933-05-21 Ta 11 Ta -10:30 Ta HST Ta
   .It 1942-02-09 Ta 03 Ta -09:30 Ta HDT Ta 1
   .It 1945-09-30 Ta 01 Ta -10:30 Ta HST Ta
   .It 1947-06-08 Ta 02:30 Ta -10 Ta HST Ta
   .El
   .Pp
   Here, local time begins 10 hours, 31 minutes and 26 seconds west of
   UT, and is a standard time abbreviated LMT.  Immediately after the
   first transition, the date is 1896-01-13 and the time is 12:01:26, and
   the following time interval is 10.5 hours west of UT, a standard time
   abbreviated HST.
   Immediately after the second transition, the date is
   1933-04-30 and the time is 03:00:00 and the following time interval is
   9.5 hours west of UT, is abbreviated HDT, and is daylight saving time.
   Immediately after the last transition the date is 1947-06-08 and the
   time is 02:30:00, and the following time interval is 10 hours west of
   UT, a standard time abbreviated HST.
   .Pp
   Here are excerpts from another example:
   .Bd -literal
   TZ="Europe/Astrakhan"
   .Ed
   .Bl -column "XXXX-XX-XX" "HH:MM:SS" "-HH:MM:SS" "TZT" "X" -compact
   .It - Ta - Ta +03:12:12 Ta LMT Ta
   .It 1924-04-30 Ta 23:47:48 Ta +03 Ta Ta
   .It 1930-06-21 Ta 01 Ta +04 Ta Ta
   .It 1981-04-01 Ta 01 Ta +05 Ta Ta 1
   .It 1981-09-30 Ta 23 Ta +04 Ta Ta
   .It \&... Ta Ta Ta Ta
   .It 2014-10-26 Ta 01 Ta +03 Ta Ta
   .It 2016-03-27 Ta 03 Ta +04 Ta Ta
   .El
   .Pp
   This time zone is east of UT, so its UT offsets are positive.  Also,
   many of its time zone abbreviations are omitted since they duplicate
   the text of the UT offset.
 .Sh LIMITATIONS  .Sh LIMITATIONS
 Time discontinuities are found by sampling the results returned by localtime  Time discontinuities are found by sampling the results returned by localtime
 at twelve-hour intervals.  at twelve-hour intervals.
 This works in all real-world cases;  This works in all real-world cases;
 one can construct artificial time zones for which this fails.  one can construct artificial time zones for which this fails.
 .Pp  .Pp
 In the output,  In the
   .Fl v
   and
   .Fl V
   output,
 .Dq UT  .Dq UT
 denotes the value returned by  denotes the value returned by
 .Xr gmtime 3 ,  .Xr gmtime 3 ,
Line 92  No attempt is currently made to have the
Line 206  No attempt is currently made to have the
 .Dq UTC  .Dq UTC
 for newer and  for newer and
 .Dq UT  .Dq UT
 for older time stamps,  for older time stamps, partly because the exact date of the
 partly because the exact date of the introduction of UTC is problematic.  introduction of UTC is problematic.
 .Sh SEE ALSO  .Sh SEE ALSO
 .Xr ctime 3 ,  .Xr ctime 3 ,
 .Xr tzfile 5 ,  .Xr tzfile 5 ,
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