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<div class="moz-cite-prefix">On 07/19/2018 08:50 AM, <a
class="moz-txt-link-abbreviated"
href="mailto:lester@lsces.co.uk">lester@lsces.co.uk</a> wrote:<br>
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<blockquote type="cite"
cite="mid:a78114ff-f0d2-4151-a139-df3b090f823f.maildroid@localhost">The
bottom line is that currently we have no way of knowing just what
data is being supplied. Even if the data matches the raw tz
version, it may or may not include the pre-<a href="tel:1970"
moz-do-not-send="true">1970</a> data archived to backzone.</blockquote>
<br>
Yes, and this is partly why I have resisted putting version
information into the installed files. Version info is typically not
available unless you've merely cloned the development Git repository
and have made no change to the data or to the 'make' parameters that
select or alter the data, a situation that is reasonably rare in
practice. It would take quite a bit of effort to get reliable
version information in real installations, and nobody knows exactly
what would be entailed in that effort. Since many people have
requested version info I had compromised by putting a version string
into tzdata.zi as a sort of experiment. The experiment has clearly
failed so far.<br>
<br>
That being said, we can improve things a bit by putting into
tzdata.zi information about whether the file 'backward' was used, as
well as whether the (dicey) file 'backzone' and the (obsolete) file
'pacificnew' were used. We can also record whether the rearguard (or
vanguard) data format was selected. Proposed patch attached.<br>
<br>
Harold, if you're changing your C++ library to look for "unknown",
this patch might append some stuff to that "unknown" string.<br>
<br>
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