RE: Question about "only" RULE lines

it's the last ... rule in effect, which is 1919 Oct lastSun at 2:00, i.e., standard time.

Thank you. That part wasn't clear from the docs.

You can debug your understanding by using the command "zdump -v America/Chicago".

Well, actually I can't, since I'm stuck using Wintel systems. And while I can read C at about the level that most 13-year-olds read Hebrew (and for almost exactly the same reasons), I had some difficulty getting through the raw zdump.c code. Any tips for compiling it using MSVC? I'm a little out of my depth here.