We started out life with 16 "reserved" bytes in binary files; one of those was appropriated for the compiler version number so we're now at...

char tzh_version[1];

char tzh_reserved[15];

Adding something such as "2013e" wouldn't exhaust the reserved bytes; it would complicate regression testing (though not unduly).

--ado

On Mon, Sep 9, 2013 at 2:21 AM, Paul Eggert <eggert@cs.ucla.edu> wrote:

One other thing. It's been privately suggested to me,
more than once, that a tz binary file should have
a version number in it, identifying which version of
the tz data it came from. Presumably this could be
a new option to 'zic', used by Makefile, e.g.,

zic -V "$(VERSION)" ...

would copy the value of VERSION into the zic output file.

Do you think this is a good idea? If so, where would
be a good place to put the version information -- a
new "version=2013e" line after the POSIX TZ string?
If we are bumping from version '2' to 'version '3'
anyway, now may be a good time to add this, if it's
a good idea to add it that is.