[... clock ...]
"The current set of places where it will try to find Olson files is:
/usr/share/zoneinfo
/user/share/lib/zoneinfo
/user/lib/zoneinfo
/user/local/etc/zoneinfo
C:/Progra~1/cygwin/usr/local/etc/zoneinfoThat's what's done if a search for a Tcl time zone definition in $tcl_library/tzdata fails.
In addition, the set of hardcoded time zone names in ::tcl::clock::LegacyTimeZone is recognized, as is any Posix time zone specifier, and the special name 'localtime'."
"...'localtime' is not recommended ..."
"... if -timezone is not supplied, the order of preference is $env(TCL_TZ)*; $env(TZ); the time zone from the Windows registry; :Tcl/Localtime (allowing a site to install its own time zone definition in $tcl_library/tzdata), and :localtime (the C library)"
"... this structure means that Starpacks for Linux and Solaris [and Mac OS X ] can safely omit $tcl_library/tzdata with minimal loss of functionality, since those platforms have the Olson files always. Windows and HP-UX need tzdata for full functionality, but can omit it if 8.4-level timezone functionality is adequate ..."