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Groups > comp.lang.c > #127105
| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Text Files |
| Date | 2018-02-26 14:40 -0800 |
| Organization | None to speak of |
| Message-ID | <ln8tbfidcx.fsf@kst-u.example.com> (permalink) |
| References | (13 earlier) <e8333d92-3eb3-4463-9720-725948c427ae@googlegroups.com> <lny3jjjjua.fsf@kst-u.example.com> <9990dccb-4af6-4d66-8a03-8842bd0f92a4@googlegroups.com> <lnzi3wiq0f.fsf@kst-u.example.com> <f206f5de-f8ad-42f2-9568-807262457ce4@googlegroups.com> |
supercat@casperkitty.com writes:
> On Sunday, February 25, 2018 at 5:55:12 PM UTC-6, Keith Thompson wrote:
>> supercat@casperkitty.com writes:
>> > The notion that UB should encourage quality implementations to
>> > behave in wackier fashion than IDB did not emerge until long after
>> > the Committee had decided which actions to classify as UB versus
>> > IDB.
>>
>> Nonsense. Nobody is talking about "encouraging" wacky behavior.
>> The point is that UB *permits* arbitrary behavior, and IDB does not.
>> That affects what I can safely do in code that's intended to be
>> portable.
>
> Perhaps the term "wacky" was unnecessarily pejorative and I should have been
> more precise: behaviors whose side-effects are undocumented, unbounded,
> unpredictable, and unrelated to the action being performed or the underlying
> platform's natural responses to such actions.
My objection was to the word "encouraging". Undefined behavior
means that the standard "imposes no requirements". That doesn't
encourage (or discourage) anything.
> An expression like "int1 > int2*int3;", where int1, int2, and int3 are all
> "int" objects without a volatile qualifier, would have two natural effects
> for any value of those objects: yield the value 0 to an enclosing expression,
> or yield the value 1 likewise. Some implementations might document that
> the expression may have other side-effects, and some platforms might document
> that they perform integer multiplication in ways that can have other side-
> effects. When neither condition applies, however, I don't think compiler
> writers would be eager to process such an expression in ways that could
> have undocumented, unbounded, and unpredictable side-effects if they didn't
> perceive the Standard as encouraging such treatment.
As you know, the behavior of overflow on signed integer multiplication
is undefined. Compilers take advantage of that for optimization. I
hardly think they need any encouragement from the standard to want to
generate faster code.
Compilers are also perfectly free to define the behavior of overflow on
signed integer multiplication. Nothing in the standard discourages them
from doing so.
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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Text Files G B <gb@gb.com> - 2018-02-14 11:47 -0400
Re: Text Files Ed Prochak <edprochak@gmail.com> - 2018-02-14 08:45 -0800
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-14 08:47 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-15 01:17 -0800
Re: Text Files gordonb.ea2mq@burditt.org (Gordon Burditt) - 2018-02-14 11:10 -0600
Re: Text Files "James R. Kuyper" <jameskuyper@verizon.net> - 2018-02-14 12:28 -0500
Re: Text Files jt@toerring.de (Jens Thoms Toerring) - 2018-02-14 21:07 +0000
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-14 15:31 -0700
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-15 06:59 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 10:20 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-14 22:51 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-15 11:04 +0100
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-15 06:16 -0800
Re: Text Files "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2018-02-15 22:22 +0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-15 15:58 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 16:31 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-15 21:31 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 21:21 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 22:17 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 23:36 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 23:48 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 10:09 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 12:57 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 15:50 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 15:50 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 17:07 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 20:44 +0000
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-17 11:22 +1300
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 17:48 +0000
Re: Text Files GOTHIER Nathan <nathan.gothier@gmail.com> - 2018-02-16 17:06 +0100
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-17 11:10 +1300
Re: Text Files supercat@casperkitty.com - 2018-02-16 14:48 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-16 15:14 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 23:25 +0000
Re: Text Files supercat@casperkitty.com - 2018-02-16 15:50 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-16 07:19 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 17:13 +0100
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-19 17:55 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-19 19:14 +0100
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-19 11:48 -0800
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 08:14 -0800
Re: Text Files Robert Wessel <robertwessel2@yahoo.com> - 2018-02-17 18:32 -0600
Re: Text Files jacobnavia <jacob@jacob.remcomp.fr> - 2018-02-15 22:57 +0100
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 22:58 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 00:19 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 02:26 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 02:57 +0000
Re: Text Files asetofsymbols@gmail.com - 2018-02-16 00:21 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 11:30 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 10:36 +0100
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 11:36 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 13:10 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 12:25 +0000
Re: Text Files Ike Naar <ike@iceland.freeshell.org> - 2018-03-06 19:33 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-03-06 20:55 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 04:42 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 16:58 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 20:02 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 21:43 +0100
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-17 04:01 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-17 13:10 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-17 05:27 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-17 14:20 +0000
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-16 09:04 -0700
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 14:31 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 06:42 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 14:58 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 07:23 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 15:24 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 04:13 -0800
Re: Text Files Siri Cruise <chine.bleu@yahoo.com> - 2018-02-16 04:29 -0800
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-20 16:41 +0000
Re: Text Files Siri Cruise <chine.bleu@yahoo.com> - 2018-02-20 09:39 -0800
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-20 19:16 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 12:46 +0000
Re: Text Files GOTHIER Nathan <nathan.gothier@gmail.com> - 2018-02-15 14:52 +0100
Re: Text Files Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-02-15 17:07 +0300
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 14:23 +0000
Re: Text Files Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-02-15 18:52 +0300
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 14:39 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 15:43 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 20:32 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 22:06 +0000
Re: Text Files GOTHIER Nathan <nathan.gothier@gmail.com> - 2018-02-15 23:12 +0100
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-15 15:12 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 23:43 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 23:54 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 23:35 +0000
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-16 17:07 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-17 02:38 +0000
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-17 17:26 +1300
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-17 11:22 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-17 12:07 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-17 04:17 -0800
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-17 16:25 +0300
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-17 07:35 -0800
Re: Text Files GOTHIER Nathan <nathan.gothier@gmail.com> - 2018-02-17 15:24 +0100
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-18 11:10 +1300
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-19 12:05 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-19 15:32 -0800
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-21 10:34 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-21 15:35 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-22 00:11 +0000
Re: Text Files Robert Wessel <robertwessel2@yahoo.com> - 2018-02-21 18:26 -0600
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-21 21:39 -0800
Re: Text Files Robert Wessel <robertwessel2@yahoo.com> - 2018-02-23 03:08 -0600
Re: Text Files supercat@casperkitty.com - 2018-02-23 16:16 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-23 16:46 -0800
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-24 02:49 -0800
Re: Text Files asetofsymbols@gmail.com - 2018-02-24 05:16 -0800
Re: Text Files "F. Russell" <fr@random.info> - 2018-02-24 14:35 +0000
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-24 08:48 -0700
Re: Text Files supercat@casperkitty.com - 2018-02-25 15:09 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-25 15:54 -0800
Re: Text Files supercat@casperkitty.com - 2018-02-26 11:04 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-26 11:52 -0800
Re: Text Files supercat@casperkitty.com - 2018-02-26 14:12 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-26 14:40 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-22 04:58 -0800
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-22 05:33 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-22 13:59 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-22 07:24 -0800
Re: Text Files supercat@casperkitty.com - 2018-02-20 12:14 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-15 21:37 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 21:34 +0000
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-15 14:15 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 10:47 +0100
Re: Text Files "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2018-02-15 22:20 +0800
Re: Text Files "F. Russell" <fr@random.info> - 2018-02-15 15:24 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 16:05 +0000
Re: Text Files "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2018-02-16 00:22 +0800
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-15 13:35 -0700
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-25 00:13 +0300
Re: Text Files bartc <bc@freeuk.com> - 2018-02-24 21:24 +0000
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-25 14:55 +0300
Re: Text Files bartc <bc@freeuk.com> - 2018-02-25 13:00 +0000
Re: Text Files Real Troll <Real.Troll@Trolls.com> - 2018-02-24 17:35 -0400
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-24 21:36 +0000
Re: Text Files Real Troll <Real.Troll@Trolls.com> - 2018-02-24 17:45 -0400
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-24 22:51 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-24 23:56 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-25 00:14 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-25 00:22 +0000
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-25 15:16 +0300
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-25 15:20 -0800
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-25 20:27 -0700
Re: Text Files gazelle@shell.xmission.com (Kenny McCormack) - 2018-02-26 06:19 +0000
Re: Text Files Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-02-26 15:35 +0300
Re: Text Files Reinhardt Behm <rbehm@hushmail.com> - 2018-02-26 20:53 +0800
Grammar Patrol (Was: Text Files) gazelle@shell.xmission.com (Kenny McCormack) - 2018-02-26 17:54 +0000
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-26 15:27 +0000
Re: Text Files Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-02-26 18:50 +0300
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-26 09:26 -0800
Re: Text Files scott@slp53.sl.home (Scott Lurndal) - 2018-02-26 19:46 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-27 09:04 +0100
Re: Text Files already5chosen@yahoo.com - 2018-02-27 00:56 -0800
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-27 22:07 +1300
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-27 14:37 +0100
Re: Text Files already5chosen@yahoo.com - 2018-02-27 07:38 -0800
Re: Text Files supercat@casperkitty.com - 2018-02-27 09:18 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-27 10:15 +0100
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-27 08:53 -0800
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-26 23:14 -0800
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-26 08:32 -0700
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-26 09:17 -0800
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-26 22:55 -0800
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-25 15:02 +0300
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-25 20:12 +0000
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