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Groups > comp.lang.c > #108810
| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Is this code considered to transgress the signed overflow purism? |
| Date | 2017-04-30 14:25 -0700 |
| Organization | None to speak of |
| Message-ID | <ln37cpk2q7.fsf@kst-u.example.com> (permalink) |
| References | (3 earlier) <ln1ssdmrc5.fsf@kst-u.example.com> <6175390e-9ea6-45f9-bf8c-d87525c332da@googlegroups.com> <odutnq$8kf$1@dont-email.me> <e58d2e1a-5bee-458b-a503-30244dbbf7fc@googlegroups.com> <kfn7f211ue0.fsf@x-alumni2.alumni.caltech.edu> |
Tim Rentsch <txr@alumni.caltech.edu> writes:
> supercat@casperkitty.com writes:
>> On Friday, April 28, 2017 at 3:19:17 AM UTC-5, David Brown wrote:
>>> The context here is C programming unless explicitly stated otherwise,
>>> and in that context left-shifting a negative value is undefined.
>>
>> Did C89 become off-topic? In C89, left-shifting a negative value was
>> defined in a way [...]
>
> As he is wont to do, supercat is talking out of school here.
> Before the C99 standard, a left shift of a negative value
> is not defined behavior but implementation-defined behavior.
> Quoting the official response in DR 81:
>
> Subclause 6.3 states that the binary operator < , among
> others, has implementation-defined aspects for signed types.
> Therefore, the answer to ``What does it mean to left shift a
> signed value?'' is that it is implementation-defined.
It would be helpful if you'd Cite the DR you're referring to:
http://www.open-std.org/jtc1/sc22/wg14/www/docs/dr_081.html
(Note that the DR incorrectly refers to "<" rather than "<<",
presumably a typo.)
I'm not sure that supercat's interpretation is entirely unreasonable
given what the C90 standard actually says.
--
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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Is this code considered to transgress the signed overflow purism? joel.rees@gmail.com - 2017-04-27 03:13 -0700
Re: Is this code considered to transgress the signed overflow purism? joel.rees@gmail.com - 2017-04-27 03:41 -0700
Re: Is this code considered to transgress the signed overflow purism? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-27 11:59 +0100
Re: Is this code considered to transgress the signed overflow purism? joel.rees@gmail.com - 2017-04-27 14:35 -0700
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-04-27 15:13 -0700
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-28 00:58 +0200
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-04-27 16:44 -0700
Re: Is this code considered to transgress the signed overflow purism? joel.rees@gmail.com - 2017-04-27 20:04 -0700
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-28 08:53 +0200
Re: Is this code considered to transgress the signed overflow purism? supercat@casperkitty.com - 2017-04-28 08:23 -0700
Re: Is this code considered to transgress the signed overflow purism? Manfred <noname@invalid.add> - 2017-04-28 18:05 +0200
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-04-28 09:22 -0700
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-04-28 12:24 -0700
Re: Is this code considered to transgress the signed overflow purism? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-29 00:03 +0100
Re: Is this code considered to transgress the signed overflow purism? supercat@casperkitty.com - 2017-04-28 16:37 -0700
Re: Is this code considered to transgress the signed overflow purism? David Kleinecke <dkleinecke@gmail.com> - 2017-04-28 17:09 -0700
Re: Is this code considered to transgress the signed overflow purism? supercat@casperkitty.com - 2017-04-28 17:34 -0700
Re: Is this code considered to transgress the signed overflow purism? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-29 01:43 +0100
Re: Is this code considered to transgress the signed overflow purism? David Kleinecke <dkleinecke@gmail.com> - 2017-04-28 21:21 -0700
Re: Is this code considered to transgress the signed overflow purism? joel.rees@gmail.com - 2017-04-29 02:04 -0700
Re: Is this code considered to transgress the signed overflow purism? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-29 11:46 +0100
Re: Is this code considered to transgress the signed overflow purism? Robert Wessel <robertwessel2@yahoo.com> - 2017-04-30 12:05 -0500
Re: Is this code considered to transgress the signed overflow purism? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-29 11:33 +0100
Re: Is this code considered to transgress the signed overflow purism? David Kleinecke <dkleinecke@gmail.com> - 2017-04-29 08:26 -0700
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-29 17:58 +0200
Re: Is this code considered to transgress the signed overflow purism? David Kleinecke <dkleinecke@gmail.com> - 2017-04-29 09:13 -0700
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-30 12:55 +0200
Re: Is this code considered to transgress the signed overflow purism? David Kleinecke <dkleinecke@gmail.com> - 2017-04-30 09:17 -0700
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-30 20:35 +0200
Re: Is this code considered to transgress the signed overflow purism? David Kleinecke <dkleinecke@gmail.com> - 2017-04-30 15:39 -0700
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-05-01 16:21 +0200
Re: Is this code considered to transgress the signed overflow purism? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-05-02 06:35 -0700
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-05-02 16:29 +0200
Re: Is this code considered to transgress the signed overflow purism? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-29 20:58 +0100
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-28 18:43 +0200
Re: Is this code considered to transgress the signed overflow purism? bartc <bc@freeuk.com> - 2017-04-28 14:09 +0100
Re: Is this code considered to transgress the signed overflow purism? scott@slp53.sl.home (Scott Lurndal) - 2017-04-28 14:23 +0000
Re: Is this code considered to transgress the signed overflow purism? bartc <bc@freeuk.com> - 2017-04-28 16:17 +0100
Re: Is this code considered to transgress the signed overflow purism? scott@slp53.sl.home (Scott Lurndal) - 2017-04-28 15:55 +0000
Re: Is this code considered to transgress the signed overflow purism? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-04-28 19:11 -0700
Re: Is this code considered to transgress the signed overflow purism? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-29 11:23 +0100
Re: Is this code considered to transgress the signed overflow purism? bartc <bc@freeuk.com> - 2017-04-29 11:31 +0100
Re: Is this code considered to transgress the signed overflow purism? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-29 12:01 +0100
Re: Is this code considered to transgress the signed overflow purism? bartc <bc@freeuk.com> - 2017-04-29 12:47 +0100
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-29 15:20 +0200
Re: Is this code considered to transgress the signed overflow purism? bartc <bc@freeuk.com> - 2017-04-29 15:22 +0100
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-29 16:52 +0200
Re: Is this code considered to transgress the signed overflow purism? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-29 15:18 +0100
Re: Is this code considered to transgress the signed overflow purism? Jean-Marc Bourguet <jm@bourguet.org> - 2017-04-29 14:25 +0200
Re: Is this code considered to transgress the signed overflow purism? Jerry Stuckle <jstucklex@attglobal.net> - 2017-04-29 08:05 -0400
Re: Is this code considered to transgress the signed overflow purism? Gareth Owen <gwowen@gmail.com> - 2017-04-29 13:34 +0100
Re: Is this code considered to transgress the signed overflow purism? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-04-29 05:55 -0700
Re: Is this code considered to transgress the signed overflow purism? GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-04-29 15:11 +0200
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-29 15:24 +0200
Re: Is this code considered to transgress the signed overflow purism? Gareth Owen <gwowen@gmail.com> - 2017-04-29 14:57 +0100
Re: Is this code considered to transgress the signed overflow purism? asetofsymbols@gmail.com - 2017-05-03 12:17 -0700
Re: Is this code considered to transgress the signed overflow purism? supercat@casperkitty.com - 2017-05-03 16:36 -0700
Re: Is this code considered to transgress the signed overflow purism? asetofsymbols@gmail.com - 2017-05-03 11:26 -0700
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-05-03 21:40 +0200
Re: Is this code considered to transgress the signed overflow purism? asetofsymbols@gmail.com - 2017-05-03 23:46 -0700
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-04-28 08:55 -0700
Re: Is this code considered to transgress the signed overflow purism? joel.rees@gmail.com - 2017-04-27 20:20 -0700
Re: Is this code considered to transgress the signed overflow purism? joel.rees@gmail.com - 2017-04-27 20:26 -0700
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-28 10:19 +0200
Re: Is this code considered to transgress the signed overflow purism? James Kuyper <jameskuyper@verizon.net> - 2017-04-28 09:57 -0400
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-28 17:06 +0200
Re: Is this code considered to transgress the signed overflow purism? supercat@casperkitty.com - 2017-04-28 08:38 -0700
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-28 18:51 +0200
Re: Is this code considered to transgress the signed overflow purism? supercat@casperkitty.com - 2017-04-29 12:43 -0700
Re: Is this code considered to transgress the signed overflow purism? Tim Rentsch <txr@alumni.caltech.edu> - 2017-04-30 14:02 -0700
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-04-30 14:25 -0700
Re: Is this code considered to transgress the signed overflow purism? Tim Rentsch <txr@alumni.caltech.edu> - 2017-04-30 15:01 -0700
Re: Is this code considered to transgress the signed overflow purism? James Kuyper <jameskuyper@verizon.net> - 2017-04-28 09:48 -0400
Re: Is this code considered to transgress the signed overflow purism? supercat@casperkitty.com - 2017-04-28 08:07 -0700
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-28 18:56 +0200
Re: Is this code considered to transgress the signed overflow purism? supercat@casperkitty.com - 2017-04-28 11:30 -0700
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-04-28 08:35 -0700
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-28 00:54 +0200
Re: Is this code considered to transgress the signed overflow purism? joel.rees@gmail.com - 2017-04-27 21:05 -0700
Re: Is this code considered to transgress the signed overflow purism? David Brown <david.brown@hesbynett.no> - 2017-04-28 10:58 +0200
Re: Is this code considered to transgress the signed overflow purism? bartc <bc@freeuk.com> - 2017-04-28 10:50 +0100
Re: Is this code considered to transgress the signed overflow purism? James Kuyper <jameskuyper@verizon.net> - 2017-04-28 10:01 -0400
Re: Is this code considered to transgress the signed overflow purism? Tim Rentsch <txr@alumni.caltech.edu> - 2017-05-02 05:06 -0700
Re: Is this code considered to transgress the signed overflow purism? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-04-28 23:57 +0100
Re: Is this code considered to transgress the signed overflow purism? Tim Rentsch <txr@alumni.caltech.edu> - 2017-04-30 12:28 -0700
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-04-30 12:41 -0700
Re: Is this code considered to transgress the signed overflow purism? bartc <bc@freeuk.com> - 2017-04-30 21:46 +0100
Re: Is this code considered to transgress the signed overflow purism? Thiago Adams <thiago.adams@gmail.com> - 2017-05-01 05:41 -0700
Re: Is this code considered to transgress the signed overflow purism? bartc <bc@freeuk.com> - 2017-05-01 13:57 +0100
Re: Is this code considered to transgress the signed overflow purism? Tim Rentsch <txr@alumni.caltech.edu> - 2017-05-02 05:30 -0700
Re: Is this code considered to transgress the signed overflow purism? bartc <bc@freeuk.com> - 2017-05-02 16:13 +0100
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-05-02 09:12 -0700
Re: Is this code considered to transgress the signed overflow purism? bartc <bc@freeuk.com> - 2017-05-02 18:15 +0100
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-05-02 11:26 -0700
Re: Is this code considered to transgress the signed overflow purism? bartc <bc@freeuk.com> - 2017-05-02 21:39 +0100
Re: Is this code considered to transgress the signed overflow purism? supercat@casperkitty.com - 2017-05-02 13:53 -0700
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-05-02 14:10 -0700
Re: Is this code considered to transgress the signed overflow purism? bartc <bc@freeuk.com> - 2017-05-02 22:36 +0100
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-05-02 15:27 -0700
Re: Is this code considered to transgress the signed overflow purism? Robert Wessel <robertwessel2@yahoo.com> - 2017-05-03 00:45 -0500
Re: Is this code considered to transgress the signed overflow purism? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-05-03 11:57 +0100
Re: Is this code considered to transgress the signed overflow purism? Robert Wessel <robertwessel2@yahoo.com> - 2017-05-03 13:34 -0500
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-05-03 12:05 -0700
Re: Is this code considered to transgress the signed overflow purism? Tim Rentsch <txr@alumni.caltech.edu> - 2017-05-05 02:58 -0700
Re: Is this code considered to transgress the signed overflow purism? Thiago Adams <thiago.adams@gmail.com> - 2017-05-03 05:26 -0700
Re: Is this code considered to transgress the signed overflow purism? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-05-03 05:54 -0700
Re: Is this code considered to transgress the signed overflow purism? Thiago Adams <thiago.adams@gmail.com> - 2017-05-03 06:49 -0700
Re: Is this code considered to transgress the signed overflow purism? Thiago Adams <thiago.adams@gmail.com> - 2017-05-03 06:51 -0700
Re: Is this code considered to transgress the signed overflow purism? jadill33@gmail.com - 2017-05-03 09:03 -0700
Re: Is this code considered to transgress the signed overflow purism? supercat@casperkitty.com - 2017-05-02 14:47 -0700
Re: Is this code considered to transgress the signed overflow purism? joel.rees@gmail.com - 2017-05-03 17:45 -0700
Re: Is this code considered to transgress the signed overflow purism? Tim Rentsch <txr@alumni.caltech.edu> - 2017-04-30 14:42 -0700
Re: Is this code considered to transgress the signed overflow purism? joel.rees@gmail.com - 2017-04-30 23:57 -0700
Re: Is this code considered to transgress the signed overflow purism? Tim Rentsch <txr@alumni.caltech.edu> - 2017-05-02 04:32 -0700
Re: Is this code considered to transgress the signed overflow purism? joel.rees@gmail.com - 2017-05-03 18:20 -0700
Re: Is this code considered to transgress the signed overflow purism? luser droog <luser.droog@gmail.com> - 2017-05-08 23:12 -0700
Re: Is this code considered to transgress the signed overflow purism? joel.rees@gmail.com - 2017-05-09 19:54 -0700
Re: Is this code considered to transgress the signed overflow purism? luser droog <luser.droog@gmail.com> - 2017-05-09 21:21 -0700
Re: Is this code considered to transgress the signed overflow purism? James Kuyper <jameskuyper@verizon.net> - 2017-04-27 10:46 -0400
Re: Is this code considered to transgress the signed overflow purism? supercat@casperkitty.com - 2017-04-27 08:37 -0700
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-04-27 09:38 -0700
Re: Is this code considered to transgress the signed overflow purism? supercat@casperkitty.com - 2017-04-27 10:17 -0700
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-04-27 12:10 -0700
Re: Is this code considered to transgress the signed overflow purism? Tim Rentsch <txr@alumni.caltech.edu> - 2017-04-30 13:50 -0700
Re: Is this code considered to transgress the signed overflow purism? Keith Thompson <kst-u@mib.org> - 2017-04-30 14:11 -0700
Re: Is this code considered to transgress the signed overflow purism? Tim Rentsch <txr@alumni.caltech.edu> - 2017-04-30 14:44 -0700
Re: Is this code considered to transgress the signed overflow purism? joel.rees@gmail.com - 2017-04-30 22:05 -0700
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