Using the TZ Database with Windows

[Jonathan M Davis via Digitalmars-d]

On Wednesday, December 10, 2014 17:21:01 Jake via Digitalmars-d wrote:
> Hello,
>
> I'm doing some research with D concerning time zones and I need
> to be able to handle a single time zone style on both Windows and
> Linux. That pretty much leaves me with the IANA Time Zone
> Database.
>
> Has anyone around here dealt with compiling the data files for
> the tz database on Windows? Or is there some easy way to do it
> for D?

I really need to catch up on reading posts in the newsgroup, or I would have
seen this a month ago. Sorry about that. In any case,
std.datetime.PosixTimeZone supports reading from the TZ database time zone
files directly. So, as long as you have those files on Windows, you can use
PosixTimeZone on there just as easily as you do on Linux. So, instead of
doing

auto tz = PosixTimeZone.getTimeZone("America/Los_Angeles");

you'd do

auto tz = PosixTimeZone.getTimeZone("America/Los_Angeles", pathToTZFiles);

and you can do something like

version(Posix)
    auto tz = PosixTimeZone.getTimeZone("America/Los_Angeles");
else version(Windows)
    auto tz = PosixTimeZone.getTimeZone("America/Los_Angeles", pathToTZFiles);

or

version(Posix)
    auto pathToTZFiles = PosixTimeZone.defaultTZDatabaseDir;
else version(Windows)
    auto pathToTZFiles = "My path on Windows";

auto tz = PosixTimeZone.getTimeZone("America/Los_Angeles", pathToTZFiles);

differentiate between Windows and the POSIX systems. In either caes, you can
then do stuff like

auto st = Clock.currTime(tz);

or

auto st = SysTime(/* whatever my arguments are */, tz);

to get a SysTime with that time zone.

Regardless, you should be able to just take the binary files from Linux and
use them directly on Windows without compiling anything. I'd like to add
support for just reading them from a tar.gz or .zip file rather than forcing
you to put them all in a directory on Windows, but I've never gotten around
to it.

- Jonathan M Davis