From: Zack Weinberg <zackw@panix.com>
To: Albert ARIBAUD <albert.aribaud@3adev.fr>
Cc: Paul Eggert <eggert@cs.ucla.edu>,
GNU C Library <libc-alpha@sourceware.org>,
Gnulib bugs <bug-gnulib@gnu.org>
Subject: Re: [PATCH 1/1] Y2038: add function __difftime64
Date: Thu, 05 Jul 2018 19:13:00 -0000 [thread overview]
Message-ID: <CAKCAbMgDUuHzLKcLoV4siZURdsQsecNgUu50fi_JLBvo++xtcQ@mail.gmail.com> (raw)
In-Reply-To: <20180705203637.66ae4947@athena>
On Thu, Jul 5, 2018 at 2:36 PM, Albert ARIBAUD <albert.aribaud@3adev.fr> wrote:
> I have had a look at gnulib in the meantime, and I would like to know
> if the following assumptions are correct:
I can't comment on anything else at all, but:
> - gnulib does not contain any module which provides the time_t type, but
> some of gnulib's modules assume there is such a type, and it might be
> wider than 32 bits.
>
> - gnulib does not provide difftime either, so ATM a difftime patch
> would only make sense in glibc, not gnulib.
<time.h> has always been required to declare a type named time_t and a
function named difftime, ever since the original C standard in 1989.
So it makes sense for gnulib not to provide either, and to assume they
exist.
In the original C standard time_t is only required to be "an
arithmetic type capable of representing times". That means it could
be any size of integer or floating-point. This has not changed as of
C11 -- the term "arithmetic type" changed to "real type" because of
the addition of complex numbers, but that's all. POSIX adds the
additional guarantee that time_t is an integer type, but still says
nothing about how wide it is.
zw
next prev parent reply other threads:[~2018-07-05 19:13 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-20 12:14 [PATCH 0/1] Y2038 support batch 3 - difftime Albert ARIBAUD (3ADEV)
2018-06-20 12:14 ` [PATCH 1/1] Y2038: add function __difftime64 Albert ARIBAUD (3ADEV)
2018-06-20 19:29 ` Paul Eggert
2018-06-20 20:55 ` Albert ARIBAUD
2018-06-21 21:17 ` Paul Eggert
2018-06-25 22:32 ` Albert ARIBAUD
2018-06-25 23:56 ` Paul Eggert
2018-06-27 11:03 ` Albert ARIBAUD
2018-07-05 18:36 ` Albert ARIBAUD
2018-07-05 19:13 ` Zack Weinberg [this message]
2018-07-05 19:40 ` Paul Eggert
2018-07-05 20:38 ` Albert ARIBAUD
2018-07-05 21:17 ` Bruno Haible
2018-07-06 5:06 ` Albert ARIBAUD
2018-07-06 22:54 ` Paul Eggert
2018-07-06 22:40 ` Paul Eggert
2018-07-06 22:37 ` Paul Eggert
2018-07-17 20:40 ` Joseph Myers
2018-07-05 20:50 ` time_t in gnulib Bruno Haible
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