[tz] Swiss time selectable for Germany

Guy Harris gharris at sonic.net
Sun Jan 8 20:46:10 UTC 2023

On Jan 7, 2023, at 6:01 PM, Benjamin Drung via tz <tz at iana.org> wrote:

> tzselect is shipped by the libc-bin binary package which comes from the
> glibc source package. I do not know and haven't investigated how
> tzselect migrates to the glibc source package (is this Debian/Ubuntu
> specific or does glibc upstream include it?).

Upstream glibc includes it.

tzdb releases include:

	the source time information files;

	source to zic and zdump, and their man pages;

	source to a version of the date command, and its man page;

	Makefile and assorted build scripts, including Awk files;

	assorted documents;


	source to versions of C library routines that use the tzdb.

This renders it something that doesn't conveniently fit into the package structure of operating systems divided into packages (various Linux distributions, as well as Darwin), as those C library routines generally belong in a "system library (or component thereof)" package.

Glibc has its own independent implementation of localtime() etc., using the tzdb, with its own code for reading tzdb files; presumably they put at least some of the rest of the tzdb release, including tzselect, into glibc because the API part is there.  Presumably updating glibc with a new tzdb release involves 1) updating libc's tzdb-reading code to support any new tzif features (and fix any bugs that we fixed, if they're also in their code, as well as picking up features they think reasonable) and 2) picking up new versions of the rest of the code and data.

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