[tz] zdump with version 1 files
Paul Eggert
eggert at cs.ucla.edu
Sat Mar 21 21:30:44 UTC 2020
On 3/21/20 2:06 PM, Hal Murray wrote:
>> As far as I can recall, only Android limits itself to 32-bit timestamps
>> (expiring in 2039) among current operating systems, even the 32-bit OSes.
> I assume you mean time_t when you say "timestamps".
I should have been clearer. I was referring to the TZif files, not to time_t.
That is, my understanding is that even 32-bit Debian, FreeBSD/Intel, etc. ship
TZif files that support 64-bit timestamps. This is because zic.c (which these
OSes use) generates only version-2 and version-3 TZif files, and these TZif
files support 64-bit timestamps. Even when zic.c is compiled on a machine where
time_t and long are only 32 bits wide, it should still generate 64-bit timestamps.
In the old days these 64-bit TZif files were arguably overkill for 32-bit OSes,
but even then the convenience of architecture-independence outweighed the
disadvantage of bloat on 32-bit platforms. And now that Internet RFC 8536 says
that version-1 TZif files should not be generated and that readers should ignore
the version 1 header and data block in TZif files, only museum-piece platforms
should have version-1 TZif files.
By "museum-piece" I mean platforms derived from tzcode2006a and earlier, as
2006b introduced 64-bit support and no longer generated 32-bit-only TZif files.
I hope we can safely ignore such platforms now.
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