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Diffstat (limited to 'doc/src/sgml/datetime.sgml')
| -rw-r--r-- | doc/src/sgml/datetime.sgml | 35 |
1 files changed, 20 insertions, 15 deletions
diff --git a/doc/src/sgml/datetime.sgml b/doc/src/sgml/datetime.sgml index 444b0ec2b93..ffd07151282 100644 --- a/doc/src/sgml/datetime.sgml +++ b/doc/src/sgml/datetime.sgml @@ -374,22 +374,27 @@ these formats: <synopsis> -<replaceable>time_zone_name</replaceable> <replaceable>offset</replaceable> -<replaceable>time_zone_name</replaceable> <replaceable>offset</replaceable> D +<replaceable>zone_abbreviation</replaceable> <replaceable>offset</replaceable> +<replaceable>zone_abbreviation</replaceable> <replaceable>offset</replaceable> D +<replaceable>zone_abbreviation</replaceable> <replaceable>time_zone_name</replaceable> @INCLUDE <replaceable>file_name</replaceable> @OVERRIDE </synopsis> </para> <para> - A <replaceable>time_zone_name</replaceable> is just the abbreviation - being defined. The <replaceable>offset</replaceable> is the zone's + A <replaceable>zone_abbreviation</replaceable> is just the abbreviation + being defined. The <replaceable>offset</replaceable> is the equivalent offset in seconds from UTC, positive being east from Greenwich and negative being west. For example, -18000 would be five hours west of Greenwich, or North American east coast standard time. <literal>D</> - indicates that the zone name represents local daylight-savings time - rather than standard time. Since all known time zone offsets are on - 15 minute boundaries, the number of seconds has to be a multiple of 900. + indicates that the zone name represents local daylight-savings time rather + than standard time. Alternatively, a <replaceable>time_zone_name</> can + be given, in which case that time zone definition is consulted, and the + abbreviation's meaning in that zone is used. This alternative is + recommended only for abbreviations whose meaning has historically varied, + as looking up the meaning is noticeably more expensive than just using + a fixed integer value. </para> <para> @@ -400,9 +405,9 @@ <para> The <literal>@OVERRIDE</> syntax indicates that subsequent entries in the - file can override previous entries (i.e., entries obtained from included - files). Without this, conflicting definitions of the same timezone - abbreviation are considered an error. + file can override previous entries (typically, entries obtained from + included files). Without this, conflicting definitions of the same + timezone abbreviation are considered an error. </para> <para> @@ -410,14 +415,14 @@ all the non-conflicting time zone abbreviations for most of the world. Additional files <filename>Australia</> and <filename>India</> are provided for those regions: these files first include the - <literal>Default</> file and then add or modify timezones as needed. + <literal>Default</> file and then add or modify abbreviations as needed. </para> <para> For reference purposes, a standard installation also contains files <filename>Africa.txt</>, <filename>America.txt</>, etc, containing information about every time zone abbreviation known to be in use - according to the <literal>zoneinfo</> timezone database. The zone name + according to the IANA timezone database. The zone name definitions found in these files can be copied and pasted into a custom configuration file as needed. Note that these files cannot be directly referenced as <varname>timezone_abbreviations</> settings, because of @@ -426,9 +431,9 @@ <note> <para> - If an error occurs while reading the time zone data sets, no new value is - applied but the old set is kept. If the error occurs while starting the - database, startup fails. + If an error occurs while reading the time zone abbreviation set, no new + value is applied and the old set is kept. If the error occurs while + starting the database, startup fails. </para> </note> |