Document the role of /usr/share/zoneinfo/GMT0. Also, improve the documentation for /usr/share/zoneinfo/posixrules. --- date.1 | 14 +++++--------- newctime.3 | 16 ++++++---------- newtzset.3 | 44 +++++++++++++++++++++++++------------------- zic.8 | 12 ++++++------ 4 files changed, 42 insertions(+), 44 deletions(-) diff --git a/date.1 b/date.1 index e8107212..01907bc7 100644 --- a/date.1 +++ b/date.1 @@ -154,15 +154,11 @@ hexadecimal (leading 0x), preceded by an optional sign. .br /usr/lib/locale/\f2L\fP/LC_TIME description of time locale \f2L\fP .br -/usr/share/zoneinfo timezone information directory +/usr/share/zoneinfo timezone directory .br -/usr/share/zoneinfo/posixrules default DST rules (obsolete, - and can cause bugs if present) +/usr/share/zoneinfo/posixrules default DST rules (obsolete) .br /usr/share/zoneinfo/GMT for UTC leap seconds -.sp -If -.B /usr/share/zoneinfo/GMT -is absent, -UTC leap seconds are loaded from -.BR /usr/share/zoneinfo/posixrules . +.PP +If /usr/share/zoneinfo/GMT is absent, +UTC leap seconds are loaded from /usr/share/zoneinfo/GMT0 if present. diff --git a/newctime.3 b/newctime.3 index 05bb7dea..3b54d4ad 100644 --- a/newctime.3 +++ b/newctime.3 @@ -292,20 +292,16 @@ will continue to exist in this form in future releases of this code. .SH FILES .ta \w'/usr/share/zoneinfo/posixrules\0\0'u -/usr/share/zoneinfo timezone information directory +/etc/localtime local timezone file .br -/usr/share/zoneinfo/localtime local timezone file +/usr/share/zoneinfo timezone directory .br -/usr/share/zoneinfo/posixrules default DST rules (obsolete, - and can cause bugs if present) +/usr/share/zoneinfo/posixrules default DST rules (obsolete) .br /usr/share/zoneinfo/GMT for UTC leap seconds -.sp -If -.B /usr/share/zoneinfo/GMT -is absent, -UTC leap seconds are loaded from -.BR /usr/share/zoneinfo/posixrules . +.PP +If /usr/share/zoneinfo/GMT is absent, +UTC leap seconds are loaded from /usr/share/zoneinfo/GMT0 if present. .SH SEE ALSO getenv(3), newstrftime(3), diff --git a/newtzset.3 b/newtzset.3 index 78b6b6ce..80617cd7 100644 --- a/newtzset.3 +++ b/newtzset.3 @@ -306,21 +306,31 @@ The abbreviations for standard and daylight saving time are and .q "\*-02". .PP -If no -.I rule -is present in -.BR TZ , -the rules specified -by the +If +.B TZ +specifies daylight saving time but does not specify a +.IR rule , +and the optional .BR tzfile (5)-format file .B posixrules -in the system time conversion information directory are used, with the -standard and daylight saving time offsets from UT replaced by those specified by -the +is present in the system time conversion information directory, the +rules in +.B posixrules +are used, with the +.B posixrules +standard and daylight saving time offsets from UT +replaced by those specified by the .I offset values in .BR TZ . +However, the +.B posixrules +file is obsolete: if it is present it is only for backward compatibility, +and it does not work reliably. +Therefore, applications that specify a +.B TZ +string with daylight saving time should specify rules explicitly. .PP For compatibility with System V Release 3.1, a semicolon .RB ( ; ) @@ -329,20 +339,16 @@ may be used to separate the from the rest of the specification. .SH FILES .ta \w'/usr/share/zoneinfo/posixrules\0\0'u -/usr/share/zoneinfo timezone information directory +/etc/localtime local timezone file .br -/usr/share/zoneinfo/localtime local timezone file +/usr/share/zoneinfo timezone directory .br -/usr/share/zoneinfo/posixrules default DST rules (obsolete, - and can cause bugs if present) +/usr/share/zoneinfo/posixrules default DST rules (obsolete) .br /usr/share/zoneinfo/GMT for UTC leap seconds -.sp -If -.B /usr/share/zoneinfo/GMT -is absent, -UTC leap seconds are loaded from -.BR /usr/share/zoneinfo/posixrules . +.PP +If /usr/share/zoneinfo/GMT is absent, +UTC leap seconds are loaded from /usr/share/zoneinfo/GMT0 if present. .SH SEE ALSO getenv(3), newctime(3), diff --git a/zic.8 b/zic.8 index c467efef..6bcef7ae 100644 --- a/zic.8 +++ b/zic.8 @@ -121,6 +121,12 @@ will act as if the input contained a link line of the form .ti +.5i Link \fItimezone\fP posixrules .sp +If +.I timezone +is +.q "\*-" +(the default), any already-existing link is removed. +.sp Unless .I timezone is .q "\*-" , @@ -131,12 +137,6 @@ and it should not be combined with if .IR timezone 's transitions are at standard time or Universal Time (UT) instead of local time. -.sp -If -.I timezone -is -.BR \*- , -any already-existing link is removed. .TP .BR "\*-r " "[\fB@\fP\fIlo\fP][\fB/@\fP\fIhi\fP]" Limit the applicability of output files -- 2.41.0