At 10:25 PM -0400 4/7/04, John E. Malmberg wrote: >Craig A. Berry wrote: >> >>If there is a discrepancy between your current offset from UTC and your timezone >>rule, then something that is explicitly testing that the two are in synch may run >>into problems. Anything that uses UTC >>or offsets from it (in short, anything using the standard C library functions) would >>have the same problem during the window between the time change and the system clock >>being reset. > >The actual problem is that there are multiple independent ways of specifying the >offset from the local time to UTC on OpenVMS for historical reasons. > >I had a conversation with the editor of the OpenVMS FAQ about this today, and there >will likely be an update to at least the OpenVMS FAQ. > >The bottom line is to prevent problems, if you are not changing to/from DST at the >exact time that the timezone rule states, you need to use the ZIC utility to create a >new timezone.
Good to know about. Just to be clear, the particular problem that manifested itself is something that happens when running the Perl test suite (specifically [.lib]vmsish.t) during the window between the DST change and the clock reset. vmsish.t uses the logical name SYS$TIMEZONE_DIFFERENTIAL as a base for comparison to test various timezone-related functions in Perl, which are in turn (usually) based on CRTL functions.* I think the safest thing to say is that running the test during this window is unsupported. *For ancient CRTLs that have a non-functioning gmtime(), Perl does its best to determine the timezone offset using SYS$TIMEZONE_DIFFERENTIAL, and if it can't do that because the logical is not defined, it assumes the local time is UTC. Perl also has rudimentary timezone rule parsing capabilities, again for very ancient CRTLs. I leave the definition of "ancient" intentionally ambiguous since I don't know at what point in the century previous to ours these CRTL issues were resolved. -- ________________________________________ Craig A. Berry mailto:[EMAIL PROTECTED] "... getting out of a sonnet is much more difficult than getting in." Brad Leithauser
