From: Lukasz Majewski <lukma@denx.de>
To: Paul Eggert <eggert@cs.ucla.edu>
Cc: libc-alpha@sourceware.org, Joseph Myers <joseph@codesourcery.com>
Subject: Re: [PATCH v2 1/2] Y2038: make __mktime_internal compatible with __time64_t
Date: Sat, 30 Mar 2019 15:39:00 +0100 [thread overview]
Message-ID: <20190330153900.0510f73c@jawa> (raw)
In-Reply-To: <2e5d75ad-2152-fc8f-2a98-892880dd0097@cs.ucla.edu>
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Hi Paul,
> On 3/29/19 7:24 AM, Lukasz Majewski wrote:
> > With __timespec64 exported (installed in usr/include/*) - there
> > would be an explicit type to show that we are Y2038 safe (when e.g.
> > debugging).
>
> That's not much of an argument for exporting __timespec64 to user
> code. When debugging a module, a developer can easily determine
> whether whether time_t is 32- or 64-bit by printing sizeof (time_t)
> in GDB, so the visibility of __timespec64 wouldn't give them any
> information that they don't already have.
Yes, indeed. From practical point of view it would be best to avoid
introducing any new types.
>
> > I do have a setup where only for glibc compilation I do disable
> > -D_TIME_BITS64, but for _all_ other source code it is enabled.
>
> Sorry, I'm not following what you mean by "disable -DTIME_BITS64". Do
> you mean that you compile applications with -D_TIME_BITS=64 and
> compile glibc without it?
Yes, exactly.
That was the case when I last time was trying to use/compile the glibc
being Y2038 safe and as the only libc on the OE/Yocto created system.
However, it was some time ago (before I did some cleanup)
The meta-y2038 relevant branch (but it is outdated now a bit):
https://github.com/lmajewski/meta-y2038/commits/y2038-glibc2.29-deploy
>
> Does -D_TIME_BITS=64 affect building the GNU C library itself, and if
> so, why?
I did not checked it with the new code, but yes the glibc was not
buildable with -D_TIME_BITS=64
> (Of course -D_TIME_BITS=64 will affect glibc's auxiliary
> programs like zdump, but these are exceptional cases; I'm worried
> about the library proper.) I thought _TIME_BITS was intended for use
> in user programs, not for use in glibc itself.
Yes, exactly. The _TIME_BITS shall be only supported when building user
programs. Glibc shall not be build with it.
>
> The answers to the above questions should be documented in
> manual/maint.texi; could you add that to your list of things to do?
>
Yes, noted.
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
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next prev parent reply other threads:[~2019-03-30 14:39 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-27 11:20 [PATCH v2 1/2] Y2038: make __mktime_internal compatible with __time64_t Lukasz Majewski
2019-02-27 11:20 ` [PATCH v2 2/2] Fix time/mktime.c and time/gmtime.c for gnulib compatibility Lukasz Majewski
2019-03-12 0:12 ` Paul Eggert
2019-03-06 11:31 ` [PATCH v2 1/2] Y2038: make __mktime_internal compatible with __time64_t Lukasz Majewski
2019-03-12 0:11 ` Paul Eggert
2019-03-12 0:36 ` Joseph Myers
2019-03-17 22:48 ` Lukasz Majewski
2019-03-18 16:27 ` Joseph Myers
2019-03-19 10:53 ` Lukasz Majewski
2019-03-12 6:58 ` Lukasz Majewski
2019-03-18 21:23 ` Paul Eggert
2019-03-19 13:39 ` Lukasz Majewski
2019-03-19 23:12 ` Paul Eggert
2019-03-20 7:03 ` Lukasz Majewski
2019-03-22 21:49 ` Paul Eggert
2019-03-23 21:34 ` Lukasz Majewski
2019-03-24 22:17 ` Lukasz Majewski
2019-03-23 11:59 ` Lukasz Majewski
2019-03-27 20:06 ` Paul Eggert
2019-03-28 8:59 ` Lukasz Majewski
2019-03-28 16:09 ` Paul Eggert
2019-03-29 14:24 ` Lukasz Majewski
2019-03-29 21:10 ` Paul Eggert
2019-03-30 14:39 ` Lukasz Majewski [this message]
2019-04-01 20:17 ` Joseph Myers
2019-04-01 20:51 ` Lukasz Majewski
2019-03-28 16:34 ` Joseph Myers
[not found] ` <20190404120715.150a5d44@jawa>
[not found] ` <20190424135748.502c34af@jawa>
2019-04-28 22:45 ` Paul Eggert
2019-04-30 7:59 ` Lukasz Majewski
2019-04-30 16:25 ` Paul Eggert
2019-05-02 7:19 ` Lukasz Majewski
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