Thanks to everyone who sent me data. The majority of systems seem to
revert to wall clock time if there is no TZ variable in the environment.
This is clearly documented for Linux, which claims it conforms to SVID
3, POSIX, and BSD 4.3. The systems that behave differently are, ... wait
for it ... surprise, surprise ...
AIX which gives you GMT
HP-UX which gives you EST (yes, indeed!)
IRIX which gives you GMT
SCO_SV which gives you GMT (documented as "implementation defined")
I'm not sure about DGUX, because the only test was run in the GMT zone.
(Ken, can you try again once we are on BST, please?)
What I have done is to implement conditional code to remove the entire
environment (since Exim makes no use of it, and flattening it all is
easy), and set up the four OS above to opt out of it. If anybody can
tell me how to enforce wall clock time in those OS, I'll consider adding
something special for them.
I currently have no information about the following systems, but have
not opted them out.
GNU/Hurd likely to be same as Linux since it uses glibc
HI-OSF
HI_UX
mips
QNX
ULTRIX
UNIX_SV
USG
Unixware7
I will also implement a "do all logging in UTC" option, but the default
will not change.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.