+IMAP folder names use UTF7-IMAP charset. Folder names that are stored in
+conf.pl must be encoded in UTF7-IMAP charset. SquirrelMail uses internal
+functions that convert folder names from/to utf7-imap charset. By default those
+functions work with iso-8859-1 charset. Other charsets are supported only
+when php mbstring extension supports them.
+
+TODO: write independent implementation of charset to utf7-imap conversion.
+
+---------------
+6. Plural forms
+---------------
+From v.1.5.1 SquirrelMail includes support for plural forms. It allows the use
+of correct translation forms with numbers. For example. "We have %s squirrel
+on the roof." and "We have %s squirrels on the roof." can be written in one
+function call without checking actual number of squirrels. The gettext
+functions also deal with non English languages that might use different word
+forms for two, five, ten or more units.
+
+Plural forms support is provided by ngettext functions that exist in the php
+gettext extension as of php 4.2.0 and by ngettext function replacements from
+the php-gettext classes (http://savannah.nongnu.org/projects/php-gettext).
+In order to provide identical functionality when the php gettext extension does
+not have ngettext support, SquirrelMail uses bindtextdomain and textdomain
+wrappers that load the missing functions.
+
+If plugin authors want to use ngettext functions without increasing php
+requirements to 4.2.0 with gettext support, they should require at least
+SquirrelMail 1.5.1, and use the sq_change_text_domain function instead of
+separate calls to bindtextdomain and textdomain. If sq_change_text_domain
+cannot be used, the sq_bindtextdomain function should be used instead of
+bindtextdomain and the sq_textdomain function should be used instead of the
+textdomain function. If these latter two SquirrelMail wrapper functions are
+used (but again, please use sq_change_text_domain), there is no need to issue
+a call to sq_bindtextdomain when a plugin reverts to the SquirrelMail domain.
+
+More information about ngettext and plural forms can be found at:
+http://www.gnu.org/software/gettext/manual/html_chapter/gettext_10.html#SEC150
+
+-----------------
+7. Language setup
+-----------------
+SquirrelMail uses set_up_language() function to setup language environment.
+Environment is setup automatically when include/validate.php is loaded.
+
+SquirrelMail gets interface language from three places:
+ a) user preference. It is set in Options -> Display Preferences -> Language.
+ preference uses language key. If user's preferences are not available (user
+ is not logged in), system tries to extract language value from
+ 'squirrelmail_language' cookie.
+ b) default squirrelmail language that is set in configuration
+ ($squirrelmail_default_language variable).
+ c) preferred language setting provided by browser. It is used only when default
+ squirrelmail language is set to empty string
+
+If language information is not available, SquirrelMail falls back to US English
+translation.
+
+-------------
+8. Time zones
+-------------
+If php install allows modifying environment variable TZ, SquirrelMail allows
+end users to select different time zone in their preferences. It can be set in
+Options -> Personal Information -> Your current timezone. Time zone is
+setup automatically when include/validate.php is loaded.
+
+If TZ variable can't be modified (php is running is safe mode and variable
+is not listed in php safe_mode_allowed_env_vars), user's time zone options are
+not visible and interface uses default webserver's time zone.
+
+SquirrelMail 1.5.0 and older store list of available time zones in
+locale/timezones.cfg. Since 1.5.1 standard times zones are moved to
+include/timezones/standard.php and time zone handling differs from older
+SquirrelMail versions. Time zone configuration is controlled in SquirrelMail
+configuration utility (conf.pl), 4. General Options -> 15. Time zone
+configuration menu option. Administrator can select standard, strict, custom
+and custom strict time zone handling.
+
+Standard handling does not differ from previous SquirrelMail versions and
+SquirrelMail uses GNU C geographical location based time zone names. Strict
+handling uses time zone codes with offset from GMT. Strict time zones should
+work on systems that don't support GNU C time zone naming. Custom and custom
+strict handling uses config/timezones.php file instead of
+include/timezones/standard.php.
+
+config/timezones.php file should store $aTimeZones array with different set of
+time zones. See default time zone set in include/timezones/standard.php.For
+example:
+
+<?php
+// World outside US border is a mirage
+
+$aTimeZones=array();
+$aTimeZones['America/New_York']['NAME']='US Eastern standard time';
+$aTimeZones['America/New_York']['TZ']='EST5EDT';
+
+$aTimeZones['America/Chicago']['NAME']='US Central standard time';
+$aTimeZones['America/Chicago']['TZ']='CST6CDT';
+
+// Oliver County, ND
+$aTimeZones['America/North_Dakota/Center']['NAME']='US, Oliver County [ND]';
+$aTimeZones['America/North_Dakota/Center']['TZ']='CST6CDT'; // CST since 1992
+
+$aTimeZones['America/Denver']['NAME']='US Mountain standard time';
+$aTimeZones['America/Denver']['TZ']='MST7MDT';
+
+$aTimeZones['America/Los_Angeles']['NAME']='US Pacific standard time';
+$aTimeZones['America/Los_Angeles']['TZ']='PST8PDT';
+
+// Aliaska
+$aTimeZones['America/Juneau']['NAME']='Aliaska, Juneau';
+$aTimeZones['America/Juneau']['TZ']='NAST9NADT';
+$aTimeZones['America/Yakutat']['NAME']='Aliaska, Yakutat';
+$aTimeZones['America/Yakutat']['TZ']='NAST9NADT';
+$aTimeZones['America/Anchorage']['NAME']='Aliaska, Anchorage';
+$aTimeZones['America/Anchorage']['TZ']='NAST9NADT';
+$aTimeZones['America/Nome']['NAME']='Aliaska, Nome';
+$aTimeZones['America/Nome']['TZ']='NAST9NADT';
+$aTimeZones['America/Adak']['NAME']='US, Aleutian Islands';
+$aTimeZones['America/Adak']['TZ']='AST10ADT';
+
+$aTimeZones['Pacific/Honolulu']['NAME']='US, Hawaii';
+$aTimeZones['Pacific/Honolulu']['TZ']='UCT10';
+$aTimeZones['America/Phoenix']['NAME']='US, Arizona';
+$aTimeZones['America/Phoenix']['TZ']='MST7'; // gmt-7
+$aTimeZones['America/Shiprock']['LINK']='America/Denver';
+
+$aTimeZones['America/Boise']['NAME']='US, South Idaho';
+$aTimeZones['America/Boise']['TZ']='MST7MDT';
+$aTimeZones['America/Indianapolis']['NAME']='US, Indiana';
+$aTimeZones['America/Indianapolis']['TZ']='EST5';
+$aTimeZones['America/Indiana/Indianapolis']['LINK']='America/Indianapolis';
+// Crawford County, Indiana
+$aTimeZones['America/Indiana/Marengo']['NAME']='US, Crawford County [IN]';
+$aTimeZones['America/Indiana/Marengo']['TZ']='EST5';
+// Starke County, Indiana
+$aTimeZones['America/Indiana/Knox']['NAME']='US, Starke County [IN]';
+$aTimeZones['America/Indiana/Knox']['TZ']='EST5';
+// Switzerland County, Indiana
+$aTimeZones['America/Indiana/Vevay']['NAME']='US, Switzerland County [IN]';
+$aTimeZones['America/Indiana/Vevay']['TZ']='EST5';
+$aTimeZones['America/Louisville']['NAME']='US, Louisville [KY]';
+$aTimeZones['America/Louisville']['TZ']='EST5EDT';
+$aTimeZones['America/Kentucky/Louisville']['LINK']='America/Louisville';
+// Wayne, Clinton, and Russell Counties, Kentucky
+$aTimeZones['America/Kentucky/Monticello']['NAME']='US, Wayne, Clinton, and Russell Counties [KY]';
+$aTimeZones['America/Kentucky/Monticello']['TZ']='EST5EDT';
+// Michigan
+$aTimeZones['America/Detroit']['NAME']='US, Michigan';
+$aTimeZones['America/Detroit']['TZ']='EST5EDT';
+// The Michigan border with Wisconsin switched from EST to CST/CDT in 1973.
+$aTimeZones['America/Menominee']['NAME']='US, Menominee [MI]';
+$aTimeZones['America/Menominee']['TZ']='CST6CDT';
+?>
+
+GNU C time zone naming should be supported by many Unix OSes. It is recommended
+way of setting time zone, because it handles historical changes and daylight
+savings specific to selected geographical location. Strict time zones might
+provide inaccurate or outdated time zone settings.
+
+If modifications in TZ environment are visible in your webserver's logs (time
+offset is changed), make sure that you can reproduce such behavior in latest php
+version and report bug to php developers. Issue can be fixed by blocking use of
+time zone (php safe mode and TZ is not listed in safe_mode_allowed_env_vars
+setting or forced_prefs plugin) or by attaching special php script with
+putenv('TZ=some time zone') call in php auto_append_file setting (suggestion is
+not tested and you might have to fix all SquirrelMail exit calls).
+
+Please note, that use of auto_append_file provides only temporally workaround
+and does not fix your php setup. Script that runs as unprivileged user, should
+be unable to affect webserver's logging system.
+
projects / squirrelmail.git / blobdiff