problems with developing with libical

Michael Cree mcree at
Wed Oct 15 01:59:21 PDT 2014

On Thu, Oct 09, 2014 at 11:27:27AM -0400, Ken Murchison wrote:
> On 10/03/2014 10:12 PM, Michael Cree wrote:
> >Now I am trying to write VCALENDARs with both VTIMEZONEs and VEVENTS
> >and using the TZID on DTSTARTs, etc.  I am currently using the builtin
> >"Pacific/Auckland" timezone and if I create a VTIMEZONE for a calendar
> >by:
> >
> >vtimezone = icalcomponent_new_clone(icaltimezone_get_component(tz));
> >
> >  Why doesn't it use a RRULE?  That's what the
> >original builtin timezone in the zoneinfo directory has.  So I am
> >wondering what is the best why to get a compact VTIMEZONE written
> >out to an icalendar event file, and with the tzname of the VTIMEZONE
> >matching the tzid value of the DTSTART parameter (as I presume they
> >should)?
> libical uses the vzic tool for creating VTIMEZONE components from the IANA
> tzdata.  As you noted, its over use of RDATEs is annoying. I have local
> changes to vzic that I'm using to create VTIMEZONE components for my
> implementation of a Time Zone Distribution Service
> <> and Time Zones by
> Reference
> <>.  The
> major changes are better use of RRULEs and sub-components sorted by DTSTART.
> I will look at integrating my changes in libical.

That would be nice.

> You can see what my VTIMEZONE for Pacific/Auckland (IANA v2014g) looks like
> here:

Complete historical information right back to the 19th century in a compact
form.  Nice.

> You can get a VTIMEZONE for just today and beyond using this request:

That's exactly what I was hoping for.  I presume, then, that I should just
put up with the verbose (and incorrect for years preceeding ~2007 for
Pacific/Auckland) VTIMEZONE presently generated by libical (it should work
fine for me in the meantime---it's just not neat) and look forward to a
later version that will include your code.


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