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From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: Junio C Hamano <gitster@pobox.com>
Cc: "René Scharfe" <l.s.r@web.de>, "Jeff King" <peff@peff.net>,
	git@vger.kernel.org
Subject: Re: [PATCH 0/6] Use time_t
Date: Tue, 28 Feb 2017 21:54:58 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1702282149160.3767@virtualbox> (raw)
In-Reply-To: <xmqqa896kuve.fsf@gitster.mtv.corp.google.com>

[-- Attachment #1: Type: text/plain, Size: 1715 bytes --]

Hi Junio,

On Tue, 28 Feb 2017, Junio C Hamano wrote:

> René Scharfe <l.s.r@web.de> writes:
> 
> > Am 28.02.2017 um 15:28 schrieb Jeff King:
> >
> >> It looks from the discussion like the sanest path forward is our own
> >> signed-64bit timestamp_t. That's unfortunate compared to using the
> >> standard time_t, but hopefully it would reduce the number of knobs
> >> (like TIME_T_IS_INT64) in the long run.
> >
> > Glibc will get a way to enable 64-bit time_t on 32-bit platforms
> > eventually (https://sourceware.org/glibc/wiki/Y2038ProofnessDesign).
> > Can platforms that won't provide a 64-bit time_t by 2038 be actually
> > used at that point?  How would we get time information on them?  How
> > would a custom timestamp_t help us?
> 
> That's a sensible "wait, let's step back a bit".  I take it that you are
> saying "time_t is just fine", and I am inclined to agree.
> 
> Right now, they may be able to have future timestamps ranging to
> year 2100 and switching to time_t would limit their ability to
> express future time to 2038 but they would be able to express
> timestamp in the past to cover most of 20th century.  Given that
> these 32-bit time_t software platforms will die off before year 2038
> (either by underlying hardware getting obsolete, or software updated
> to handle 64-bit time_t), the (temporary) loss of 2038-2100 range
> would not be too big a deal to warrant additional complexity.

You seem to assume that time_t is required to be signed. But from my
understanding that is only guaranteed by POSIX, not by ISO C.

We may very well buy ourselves a ton of trouble if we decide to switch to
`time_t` rather than to `int64_t`.

Ciao,
Johannes

  parent reply	other threads:[~2017-02-28 21:28 UTC|newest]

Thread overview: 113+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-27 21:30 [PATCH 0/6] Use time_t Johannes Schindelin
2017-02-27 21:30 ` [PATCH 1/6] t0006 & t5000: prepare for 64-bit time_t Johannes Schindelin
2017-02-27 22:55   ` Junio C Hamano
2017-02-27 21:30 ` [PATCH 2/6] Specify explicitly where we parse timestamps Johannes Schindelin
2017-02-27 22:37   ` Junio C Hamano
2017-02-27 22:51     ` Junio C Hamano
2017-02-28 10:49       ` Johannes Schindelin
2017-02-27 21:31 ` [PATCH 3/6] Introduce a new "printf format" for timestamps Johannes Schindelin
2017-03-01 18:20   ` Junio C Hamano
2017-03-01 19:53     ` Junio C Hamano
2017-02-27 21:31 ` [PATCH 4/6] Prepare for timestamps to use 64-bit signed types Johannes Schindelin
2017-02-27 21:31 ` [PATCH 5/6] ref-filter: avoid using `unsigned long` for catch-all data type Johannes Schindelin
2017-02-27 21:31 ` [PATCH 6/6] Use time_t where appropriate Johannes Schindelin
2017-02-27 22:48 ` [PATCH 0/6] Use time_t Junio C Hamano
2017-02-28 11:32   ` Johannes Schindelin
2017-02-28 14:28 ` Jeff King
2017-02-28 15:01   ` Johannes Schindelin
2017-02-28 16:38   ` René Scharfe
2017-02-28 18:55     ` Junio C Hamano
2017-02-28 20:04       ` Jeff King
2017-02-28 20:54       ` Johannes Schindelin [this message]
2017-02-28 21:31         ` Jeff King
2017-02-28 21:31         ` René Scharfe
2017-02-28 23:10           ` Johannes Schindelin
2017-03-01  0:59             ` René Scharfe
2017-02-28 17:26   ` Junio C Hamano
2017-02-28 20:01     ` Jeff King
2017-02-28 22:27       ` Junio C Hamano
2017-02-28 22:33         ` Jeff King
2017-03-01 17:23           ` Junio C Hamano
2017-04-02 19:06 ` [PATCH v2 0/8] Introduce timestamp_t for timestamps Johannes Schindelin
2017-04-02 19:06   ` [PATCH v2 1/8] ref-filter: avoid using `unsigned long` for catch-all data type Johannes Schindelin
2017-04-03  4:22     ` Torsten Bögershausen
2017-04-03 22:47       ` Johannes Schindelin
2017-04-02 19:06   ` [PATCH v2 2/8] t0006 & t5000: prepare for 64-bit timestamps Johannes Schindelin
2017-04-02 19:06   ` [PATCH v2 3/8] t0006 & t5000: skip "far in the future" test when time_t is too limited Johannes Schindelin
2017-04-02 19:06   ` [PATCH v2 4/8] Specify explicitly where we parse timestamps Johannes Schindelin
2017-04-03  4:26     ` Torsten Bögershausen
2017-04-03 22:50       ` Johannes Schindelin
2017-04-02 19:06   ` [PATCH v2 5/8] Introduce a new "printf format" for timestamps Johannes Schindelin
2017-04-02 19:06   ` [PATCH v2 6/8] Introduce a new data type " Johannes Schindelin
2017-04-02 19:07   ` [PATCH v2 7/8] Abort if the system time cannot handle one of our timestamps Johannes Schindelin
2017-04-02 19:07   ` [PATCH v2 8/8] Use uintmax_t for timestamps Johannes Schindelin
2017-04-20 20:52   ` [PATCH v3 0/8] Introduce timestamp_t " Johannes Schindelin
2017-04-20 20:52     ` [PATCH v3 1/8] ref-filter: avoid using `unsigned long` for catch-all data type Johannes Schindelin
2017-04-20 20:52     ` [PATCH v3 2/8] t0006 & t5000: prepare for 64-bit timestamps Johannes Schindelin
2017-04-20 20:58     ` [PATCH v3 3/8] t0006 & t5000: skip "far in the future" test when time_t is too limited Johannes Schindelin
2017-04-20 20:58     ` [PATCH v3 4/8] Specify explicitly where we parse timestamps Johannes Schindelin
2017-04-20 20:58     ` [PATCH v3 5/8] Introduce a new "printf format" for timestamps Johannes Schindelin
2017-04-20 20:58     ` [PATCH v3 6/8] Introduce a new data type " Johannes Schindelin
2017-04-20 20:58     ` [PATCH v3 7/8] Abort if the system time cannot handle one of our timestamps Johannes Schindelin
2017-04-20 20:59     ` [PATCH v3 8/8] Use uintmax_t for timestamps Johannes Schindelin
2017-04-21  6:05     ` [PATCH v3 0/8] Introduce timestamp_t " Junio C Hamano
2017-04-21 10:44       ` Johannes Schindelin
2017-04-21 10:45     ` [PATCH v4 0/9] " Johannes Schindelin
2017-04-21 10:45       ` [PATCH v4 1/9] ref-filter: avoid using `unsigned long` for catch-all data type Johannes Schindelin
2017-04-21 10:45       ` [PATCH v4 2/9] t0006 & t5000: prepare for 64-bit timestamps Johannes Schindelin
2017-04-21 10:45       ` [PATCH v4 3/9] t0006 & t5000: skip "far in the future" test when time_t is too limited Johannes Schindelin
2017-04-21 10:45       ` [PATCH v4 4/9] Specify explicitly where we parse timestamps Johannes Schindelin
2017-04-24  3:19         ` Junio C Hamano
2017-04-21 10:45       ` [PATCH v4 5/9] Introduce a new "printf format" for timestamps Johannes Schindelin
2017-04-21 10:45       ` [PATCH v4 6/9] Introduce a new data type " Johannes Schindelin
2017-04-21 10:45       ` [PATCH v4 7/9] Abort if the system time cannot handle one of our timestamps Johannes Schindelin
2017-04-24  3:16         ` Junio C Hamano
2017-04-24 13:57           ` Johannes Schindelin
2017-04-25  2:37             ` Junio C Hamano
2017-04-25  3:56             ` Junio C Hamano
2017-04-21 10:46       ` [PATCH v4 8/9] Use uintmax_t for timestamps Johannes Schindelin
2017-04-24  3:24         ` Junio C Hamano
2017-04-24 10:28           ` Johannes Schindelin
2017-04-25  3:59             ` Junio C Hamano
2017-04-25 20:10               ` Johannes Schindelin
2017-04-26  1:52                 ` Junio C Hamano
2017-04-26  3:45                   ` Junio C Hamano
2017-04-26  9:32                   ` Johannes Schindelin
2017-04-26 13:18                     ` Junio C Hamano
2017-04-21 10:46       ` [PATCH v4 9/9] show_date_ident(): defer date overflow check Johannes Schindelin
2017-04-24  3:29       ` [PATCH v4 0/9] Introduce timestamp_t for timestamps Junio C Hamano
2017-04-24  6:15         ` Jacob Keller
2017-04-24 14:02           ` Johannes Schindelin
2017-04-24 11:37         ` Jeff King
2017-04-25 20:13           ` Johannes Schindelin
2017-04-24 14:00         ` Johannes Schindelin
2017-04-24 13:57       ` [PATCH v5 0/8] " Johannes Schindelin
2017-04-24 13:57         ` [PATCH v5 1/8] ref-filter: avoid using `unsigned long` for catch-all data type Johannes Schindelin
2017-04-24 13:57         ` [PATCH v5 2/8] t0006 & t5000: prepare for 64-bit timestamps Johannes Schindelin
2017-04-24 13:58         ` [PATCH v5 3/8] t0006 & t5000: skip "far in the future" test when time_t is too limited Johannes Schindelin
2017-04-24 13:58         ` [PATCH v5 4/8] Specify explicitly where we parse timestamps Johannes Schindelin
2017-04-25  5:59           ` Junio C Hamano
2017-04-24 13:58         ` [PATCH v5 5/8] Introduce a new "printf format" for timestamps Johannes Schindelin
2017-04-24 13:58         ` [PATCH v5 6/8] Introduce a new data type " Johannes Schindelin
2017-04-26 16:43           ` Johannes Sixt
2017-04-26 19:18             ` Johannes Schindelin
2017-04-26 22:32           ` René Scharfe
2017-04-24 13:58         ` [PATCH v5 7/8] Abort if the system time cannot handle one of our timestamps Johannes Schindelin
2017-04-24 13:58         ` [PATCH v5 8/8] Use uintmax_t for timestamps Johannes Schindelin
2017-04-26 16:36           ` Johannes Sixt
2017-04-26 19:09             ` Johannes Schindelin
2017-04-25 21:54         ` [PATCH v5 0/8] Introduce timestamp_t " René Scharfe
2017-04-25 22:22           ` Johannes Schindelin
2017-04-26 22:09             ` René Scharfe
2017-04-26  1:56           ` Junio C Hamano
2017-04-26 19:20         ` [PATCH v6 " Johannes Schindelin
2017-04-26 19:26           ` [PATCH v6 1/8] ref-filter: avoid using `unsigned long` for catch-all data type Johannes Schindelin
2017-04-26 19:26           ` [PATCH v6 2/8] t0006 & t5000: prepare for 64-bit timestamps Johannes Schindelin
2017-04-26 19:26           ` [PATCH v6 3/8] t0006 & t5000: skip "far in the future" test when time_t is too limited Johannes Schindelin
2017-04-26 19:26           ` [PATCH v6 4/8] Specify explicitly where we parse timestamps Johannes Schindelin
2017-04-26 19:29           ` [PATCH v6 5/8] Introduce a new "printf format" for timestamps Johannes Schindelin
2017-04-26 19:29           ` [PATCH v6 6/8] Introduce a new data type " Johannes Schindelin
2017-05-20  5:47             ` [PATCH] name-rev: change a "long" variable to timestamp_t Junio C Hamano
2017-05-22 13:39               ` Johannes Schindelin
2017-04-26 19:29           ` [PATCH v6 7/8] Abort if the system time cannot handle one of our timestamps Johannes Schindelin
2017-04-26 19:29           ` [PATCH v6 8/8] Use uintmax_t for timestamps Johannes Schindelin

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