From patchwork Fri Jan 16 22:05:50 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: J William Piggott X-Patchwork-Id: 4717 Received: (qmail 32232 invoked by alias); 16 Jan 2015 22:06:01 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 32222 invoked by uid 89); 16 Jan 2015 22:06:00 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00, FREEMAIL_FROM, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=ham version=3.3.2 X-HELO: mout.gmx.net Message-ID: <54B98B3E.4020400@gmx.com> Date: Fri, 16 Jan 2015 17:05:50 -0500 From: JWP MIME-Version: 1.0 To: libc-alpha@sourceware.org Subject: [PATCH] manual/time.texi: TZ and zoneinfo updates References: <54B989EA.3080307@gmx.com> In-Reply-To: <54B989EA.3080307@gmx.com> X-UI-Out-Filterresults: notjunk:1; Update the manual regarding the use of the TZ environment variable and that the zoneinfo data is no longer installed by glibc. Signed-off-by: J William Piggott --- The following changes since commit 026eb207eda8cc93f6f7f0980f0a8e51587d8011: S390: Get rid of linknamespace failures for utmp functions. (2015-01-16 09:18:58 +0100) are available in the git repository at: git@github.com:jwpi/glibc.git time for you to fetch changes up to 30b60e63821928e11208e6319fd05ca0c39248a7: manual/time.texi: TZ and zoneinfo updates (2015-01-16 15:34:50 -0500) Change log: 2015-01-16 J William Piggott * manual/search.texi: TZ and zoneinfo updates manual/time.texi | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/manual/time.texi b/manual/time.texi index 8a5f94e..5aaa042 100644 --- a/manual/time.texi +++ b/manual/time.texi @@ -403,8 +403,11 @@ represents an elapsed time. When interpreted as a calendar time value, it represents the number of seconds elapsed since 00:00:00 on January 1, 1970, Coordinated Universal Time. (This calendar time is sometimes referred to as the @dfn{epoch}.) POSIX requires that this count not -include leap seconds, but on some systems this count includes leap seconds -if you set @code{TZ} to certain values (@pxref{TZ Variable}). +include leap seconds. On nonstandard systems where this count includes +leap seconds, the system must be configured to use the ``right'' (now +called leaps) timezone database by replacing all of the files in the +root of the ``zoneinfo'' directory with the ``right'' timezone files in +order to output the correct civil timescales (@pxref{TZ Variable}). Note that a simple time has no concept of local time zone. Calendar Time @var{T} is the same instant in time regardless of where on the @@ -2358,6 +2361,9 @@ set @code{TZ} if you are using a computer over a network from a different time zone, and would like times reported to you in the time zone local to you, rather than what is local to the computer. +If the @code{TZ} environment variable is set to a value that @theglibc{} +cannot interpret correctly then UTC will be used by default. + In POSIX.1 systems the value of the @code{TZ} variable can be in one of three formats. With @theglibc{}, the most common format is the last one, which can specify a selection from a large database of time @@ -2500,7 +2506,7 @@ zone. @pindex /etc/localtime @pindex localtime -If the @code{TZ} environment variable does not have a value, the +If the @code{TZ} environment variable is not set, the operation chooses a time zone by default. In @theglibc{}, the default time zone is like the specification @samp{TZ=:/etc/localtime} (or @samp{TZ=:/usr/local/etc/localtime}, depending on how @theglibc{} @@ -2509,20 +2515,22 @@ rule for choosing the default time zone, so there is little we can say about them. @cindex time zone database -@pindex /share/lib/zoneinfo +@pindex /usr/share/zoneinfo @pindex zoneinfo If @var{characters} begins with a slash, it is an absolute file name; otherwise the library looks for the file -@w{@file{/share/lib/zoneinfo/@var{characters}}}. The @file{zoneinfo} +@w{@file{/usr/share/zoneinfo/@var{characters}}}. The @file{zoneinfo} directory contains data files describing local time zones in many different parts of the world. The names represent major cities, with subdirectories for geographical areas; for example, @file{America/New_York}, @file{Europe/London}, @file{Asia/Hong_Kong}. These data files are installed by the system administrator, who also sets @file{/etc/localtime} to point to the data file for the local time -zone. @Theglibc{} comes with a large database of time zone +zone. @Theglibc{} is compatible with The IANA Time Zone Database, +sometimes called tz, or zoneinfo. This is a large database of time zone information for most regions of the world, which is maintained by a -community of volunteers and put in the public domain. +community of volunteers and put in the public domain. It is located at +@url{http://www.iana.org/time-zones}. @node Time Zone Functions @subsection Functions and Variables for Time Zones