Ran into issues with TZ in the past too. ActiveState Perl is picky.
I use the PST8PDT format for TZ, but could be other Window programs that
won't accept that.
$ TZ="" date
Tue, May 9, 2017 2:02:50 PM
$ TZ="America/Los_Angeles" date
Tue, May 9, 2017 7:01:39 AM
$ TZ="PST8PEDT" date
Tue, May 9, 2017 7:01:49 AM
Cygwin Perl
=========
$ TZ="" perl -e "print scalar localtime(time);"
Tue May 9 13:59:57 2017
$ TZ="America/Los_Angeles" perl -e "print scalar localtime(time);"
Tue May 9 07:00:28 2017
$ TZ="PST8PDT" perl -e "print scalar localtime(time);"
Tue May 9 07:00:45 2017
ActiveState Perl
============
$ TZ="" ./perl -e "print scalar localtime(time);"
Tue May 9 07:06:06 2017
$ TZ="America/Los_Angeles" ./perl -e "print scalar localtime(time);"
Tue May 9 15:06:29 2017
$ TZ="PST8PDT" ./perl -e "print scalar localtime(time);"
Tue May 9 07:06:47 2017
Glenn
====================================================================
Hi,
Currently, all commands in a Cygwin command window are run with the TZ
environment variable set.
It is set by /etc/profile.d/tzset.sh (or its csh equivalent,
/etc/profile.d/tzset.csh).
Setting TZ is harmful in two ways:
1) When the user changes the time zone (through the Windows Control Panel) -
for example when traveling - the programs run in the Cygwin command
window will display a stale notion of local time. Only after the user
closes and re-opens a new Cygwin command window, will the programs
display local time according to the new time zone.
2) It causes native Windows programs (built through mingw, MSVC) to assume
a time zone that is different from the intended one and different from
the one that the user has set in the Windows Control Panel (see APPENDIX 1
below). This is because in most geographies, the values of TZ (produced
by winsup/utils/tzset.c and winsup/utils/tzmap.h) contains a slash, and
the tzset() function in the Microsoft CRT does not understand this syntax
- it understands only a different syntax
https://msdn.microsoft.com/en-us/library/90s5c885.aspx .
When TZ is not set, both Cygwin and native Windows programs take their time
zone information from the Windows Control Panel settings. See APPENDIX 2 below
and https://lists.gnu.org/archive/html/bug-gnulib/2017-05/msg00035.html .
What are the benefits of setting the TZ environment variable? I don't see any!
===> Please remove /etc/profile.d/tzset.{sh,csh} ! <===
Side note: An empty TZ value is equivalent to an unset TZ variable for mingw
and MSVC compiled programs, but not for Cygwin programs (which interpret it as
GMT). See APPENDIX 2 below.
Bruno
======= APPENDIX 1: Effects of Cygwin-set TZ on programs =========
$ ./showtime-cygwin.exe
now = 17286 17 157
as GMT: 2017-04-30 17:02:37 dst=0
as GMT: Sun Apr 30 17:02:37 2017
as localtime: 2017-04-30 19:02:37 dst=1
as localtime: Sun Apr 30 19:02:37 2017 tzname[0] = CET, tzname[1] = CEST
$ ./showtime-mingw.exe
now = 17286 17 175
as GMT: 2017-04-30 17:02:55 dst=0
as GMT: Sun Apr 30 17:02:55 2017
as localtime: 2017-04-30 18:02:55 dst=1
as localtime: Sun Apr 30 18:02:55 2017 tzname[0] = Eur, tzname[1] = ope
$ ./showtime-msvc.exe
now = 17286 17 234
as GMT: 2017-04-30 17:03:54 dst=0
as GMT: Sun Apr 30 17:03:54 2017
as localtime: 2017-04-30 18:03:54 dst=1
as localtime: Sun Apr 30 18:03:54 2017 tzname[0] = Eur, tzname[1] = ope
======= APPENDIX 2: Effects of unset TZ or empty TZ on programs =======
Cygwin: makes a difference
$ (unset TZ; ./showtime-cygwin.exe )
now = 17292 20 3383
as GMT: 2017-05-06 20:56:23 dst=0
as GMT: Sat May 6 20:56:23 2017
as localtime: 2017-05-06 22:56:23 dst=1
as localtime: Sat May 6 22:56:23 2017 tzname[0] = WEST, tzname[1] = WEST
$ TZ= ./showtime-cygwin.exe
now = 17292 20 3420
as GMT: 2017-05-06 20:57:00 dst=0
as GMT: Sat May 6 20:57:00 2017
as localtime: 2017-05-06 20:57:00 dst=0
as localtime: Sat May 6 20:57:00 2017 tzname[0] = GMT, tzname[1] =
mingw: no difference
$ (unset TZ; ./showtime-mingw.exe )
now = 17292 20 3395
as GMT: 2017-05-06 20:56:35 dst=0
as GMT: Sat May 06 20:56:35 2017
as localtime: 2017-05-06 22:56:35 dst=1
as localtime: Sat May 06 22:56:35 2017 tzname[0] = W. Europe Standard Time,
tzname[1] = W. Europe Summer Time
$ TZ= ./showtime-mingw.exe
now = 17292 20 3426
as GMT: 2017-05-06 20:57:06 dst=0
as GMT: Sat May 06 20:57:06 2017
as localtime: 2017-05-06 22:57:06 dst=1
as localtime: Sat May 06 22:57:06 2017 tzname[0] = W. Europe Standard Time,
tzname[1] = W. Europe Summer Time
msvc: no difference
$ (unset TZ; ./showtime-msvc.exe )
now = 17292 20 3401
as GMT: 2017-05-06 20:56:41 dst=0
as GMT: Sat May 6 20:56:41 2017
as localtime: 2017-05-06 22:56:41 dst=1
as localtime: Sat May 6 22:56:41 2017 tzname[0] = W. Europe Standard Time,
tzname[1] = W. Europe Summer Time
$ TZ= ./showtime-msvc.exe
now = 17292 20 3431
as GMT: 2017-05-06 20:57:11 dst=0
as GMT: Sat May 6 20:57:11 2017
as localtime: 2017-05-06 22:57:11 dst=1
as localtime: Sat May 6 22:57:11 2017 tzname[0] = W. Europe Standard Time,
tzname[1] = W. Europe Summer Time
--
Problem reports: http://cygwin.com/problems.html
FAQ: http://cygwin.com/faq/
Documentation: http://cygwin.com/docs.html
Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
--
Problem reports: http://cygwin.com/problems.html
FAQ: http://cygwin.com/faq/
Documentation: http://cygwin.com/docs.html
Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
