Michael Lindner <mlindner@idttechnology.com> writes:
Is there a localtime()-like implementation out there that can do what I need, or do I have to write one?
I think the latter, unless you want to use Java <http://www.bmsi.com/java/#TZ>. Jonathan Lennox proposed a C API in http://www.cl.cam.ac.uk/~mgk25/time/c/proposal-lennox.txt I vaguely recall that something got implemented; perhaps you can consult the archive of the tz mailing list.
And if not and I have to write one, what code base is the "correct" one to start from (e.g. Linux, tzcode2003e.tar.gz from elsi.nci.nih.gov, etc.)?
GNU/Linux (i.e., glibc) and tzcode are both reasonable. Neither is bug-free. GNU/Linux currently has some problems with negative time stamps; tzcode with large 64-bit time_t values -- choose your poison. GNU/Linux is LPGLed and is probably more widely used; tzcode is public domain.