| /* Provide tzset for systems that don't have it or for which it's broken. | |
| Copyright (C) 2001-2003, 2005-2007, 2009-2023 Free Software Foundation, Inc. | |
| This file is free software: you can redistribute it and/or modify | |
| it under the terms of the GNU Lesser General Public License as | |
| published by the Free Software Foundation, either version 3 of the | |
| License, or (at your option) any later version. | |
| This file is distributed in the hope that it will be useful, | |
| but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| GNU Lesser General Public License for more details. | |
| You should have received a copy of the GNU Lesser General Public License | |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ | |
| /* written by Jim Meyering */ | |
| /* Specification. */ | |
| void | |
| rpl_tzset (void) | |
| { | |
| /* Rectify the value of the environment variable TZ. | |
| There are four possible kinds of such values: | |
| - Traditional US time zone names, e.g. "PST8PDT". Syntax: see | |
| <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/tzset> | |
| - Time zone names based on geography, that contain one or more | |
| slashes, e.g. "Europe/Moscow". | |
| - Time zone names based on geography, without slashes, e.g. | |
| "Singapore". | |
| - Time zone names that contain explicit DST rules. Syntax: see | |
| <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03> | |
| The Microsoft CRT understands only the first kind. It produces incorrect | |
| results if the value of TZ is of the other kinds. | |
| But in a Cygwin environment, /etc/profile.d/tzset.sh sets TZ to a value | |
| of the second kind for most geographies, or of the first kind in a few | |
| other geographies. If it is of the second kind, neutralize it. For the | |
| Microsoft CRT, an absent or empty TZ means the time zone that the user | |
| has set in the Windows Control Panel. | |
| If the value of TZ is of the third or fourth kind -- Cygwin programs | |
| understand these syntaxes as well --, it does not matter whether we | |
| neutralize it or not, since these values occur only when a Cygwin user | |
| has set TZ explicitly; this case is 1. rare and 2. under the user's | |
| responsibility. */ | |
| const char *tz = getenv ("TZ"); | |
| if (tz != NULL && strchr (tz, '/') != NULL) | |
| _putenv ("TZ="); | |
| /* On native Windows, tzset() is deprecated. Use _tzset() instead. See | |
| <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/posix-tzset> | |
| <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/tzset> */ | |
| _tzset (); | |
| tzset (); | |
| } | |