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| From | Eric Sosman <esosman@comcast-dot-net.invalid> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Pointer Arithmetic & UB |
| Date | 2012-12-17 08:47 -0500 |
| Organization | A noiseless patient Spider |
| Message-ID | <kan7qh$7lf$1@dont-email.me> (permalink) |
| References | (5 earlier) <50C8DCC5.1020205@spamcop.net> <kaarct$au1$1@dont-email.me> <50C8F391.3050605@verizon.net> <kabdua$rn3$1@dont-email.me> <874njlkn92.fsf@bazspaz.fatphil.org> |
On 12/17/2012 5:04 AM, Phil Carmody wrote:
> Eric Sosman <esosman@comcast-dot-net.invalid> writes:
>>[...]
>> Although I haven't studied the C11 stuff in detail, I'd
>> be surprised (and disappointed!) if in
>>
>> #define WHICH 1
>> ...
>> int r = WHICH * (x + y) + (1 - WHICH) * (z - x);
>>
>> ... the Standard required that `z - x' be evaluated at all,
>> much less "before" the entire expression.
>
> I am deliriously happy that the Standard requires that (the implementation
> behave as if) `z - x' is evaluated. That would be, and is, consistent behaviour.
>
> Pulling out the big cannon - if z and x are volatile, of course you
> want x read twice, and z read once.
If `x' is volatile, the behavior is undefined.
--
Eric Sosman
esosman@comcast-dot-net.invalid
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Pointer Arithmetic & UB Edward Rutherford <edward.p.rutherford79@REMOVETHIS.gmail.com> - 2012-12-10 17:14 +0000
Re: Pointer Arithmetic & UB "christian.bau" <christian.bau@cbau.wanadoo.co.uk> - 2012-12-10 09:35 -0800
Re: Pointer Arithmetic & UB James Kuyper <jameskuyper@verizon.net> - 2012-12-10 12:55 -0500
Re: Pointer Arithmetic & UB Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-12-10 13:25 -0500
Re: Pointer Arithmetic & UB falk@rahul.net (Edward A. Falk) - 2012-12-11 00:46 +0000
Re: Pointer Arithmetic & UB James Kuyper <jameskuyper@verizon.net> - 2012-12-10 21:28 -0500
Re: Pointer Arithmetic & UB Ken Brody <kenbrody@spamcop.net> - 2012-12-12 14:36 -0500
Re: Pointer Arithmetic & UB glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-12 20:35 +0000
Re: Pointer Arithmetic & UB James Kuyper <jameskuyper@verizon.net> - 2012-12-12 15:57 -0500
Re: Pointer Arithmetic & UB Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-12-12 16:02 -0500
Re: Pointer Arithmetic & UB James Kuyper <jameskuyper@verizon.net> - 2012-12-12 16:13 -0500
Re: Pointer Arithmetic & UB Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-12-12 21:18 -0500
Re: Pointer Arithmetic & UB James Kuyper <jameskuyper@verizon.net> - 2012-12-12 22:42 -0500
Re: Pointer Arithmetic & UB Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-12-17 12:04 +0200
Re: Pointer Arithmetic & UB Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-12-17 08:47 -0500
Re: Pointer Arithmetic & UB Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-17 14:58 +0000
Re: Pointer Arithmetic & UB Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-12-17 10:59 -0500
Re: Pointer Arithmetic & UB Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-17 17:26 +0000
Re: Pointer Arithmetic & UB Shao Miller <sha0.miller@gmail.com> - 2012-12-17 19:33 -0500
Re: Pointer Arithmetic & UB Ken Brody <kenbrody@spamcop.net> - 2012-12-20 11:00 -0500
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-20 10:03 -0800
Re: Pointer Arithmetic & UB Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-20 22:02 +0000
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-21 13:09 -0800
Re: Pointer Arithmetic & UB glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-21 22:40 +0000
Re: Pointer Arithmetic & UB Ken Brody <kenbrody@spamcop.net> - 2012-12-21 23:39 -0500
Re: Pointer Arithmetic & UB glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-22 06:50 +0000
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-22 00:15 -0800
Re: Pointer Arithmetic & UB glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-22 10:34 +0000
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-22 09:32 -0800
Re: Pointer Arithmetic & UB glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-23 09:38 +0000
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-23 09:55 -0800
Re: Pointer Arithmetic & UB Ken Brody <kenbrody@spamcop.net> - 2012-12-26 13:35 -0500
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-27 09:03 -0800
Re: Pointer Arithmetic & UB Ken Brody <kenbrody@spamcop.net> - 2012-12-27 21:31 -0500
Re: Pointer Arithmetic & UB Philip Lantz <prl@canterey.us> - 2012-12-28 01:55 -0800
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-29 13:43 -0800
Re: Pointer Arithmetic & UB Philip Lantz <prl@canterey.us> - 2012-12-28 01:39 -0800
Re: Pointer Arithmetic & UB glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-28 11:31 +0000
Re: Pointer Arithmetic & UB Keith Thompson <kst-u@mib.org> - 2012-12-28 08:47 -0800
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-29 17:45 -0800
Re: Pointer Arithmetic & UB glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-30 04:06 +0000
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2013-01-02 10:08 -0800
Re: Pointer Arithmetic & UB Ken Brody <kenbrody@spamcop.net> - 2012-12-26 13:29 -0500
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-27 07:55 -0800
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-27 08:01 -0800
Re: Pointer Arithmetic & UB Ken Brody <kenbrody@spamcop.net> - 2012-12-27 21:10 -0500
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-29 18:03 -0800
Re: Pointer Arithmetic & UB Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-23 03:48 +0000
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-23 10:22 -0800
Re: Pointer Arithmetic & UB Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-27 10:34 +0000
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-27 10:16 -0800
Re: Pointer Arithmetic & UB Ben Bacarisse <ben.usenet@bsb.me.uk> - 2013-01-10 17:26 +0000
Re: Pointer Arithmetic & UB Robert Wessel <robertwessel2@yahoo.com> - 2012-12-20 12:21 -0600
Re: Pointer Arithmetic & UB James Kuyper <jameskuyper@verizon.net> - 2012-12-20 13:40 -0500
Re: Pointer Arithmetic & UB Robert Wessel <robertwessel2@yahoo.com> - 2012-12-20 13:32 -0600
Re: Pointer Arithmetic & UB James Kuyper <jameskuyper@verizon.net> - 2012-12-20 14:58 -0500
Re: Pointer Arithmetic & UB glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-20 21:54 +0000
Re: Pointer Arithmetic & UB Lanarcam <lanarcam1@yahoo.fr> - 2012-12-20 19:49 +0100
Re: Pointer Arithmetic & UB Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-12-21 02:38 +0200
Re: Pointer Arithmetic & UB Ken Brody <kenbrody@spamcop.net> - 2012-12-21 14:33 -0500
Re: Pointer Arithmetic & UB Shao Miller <sha0.miller@gmail.com> - 2012-12-21 03:18 -0500
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-21 13:16 -0800
Re: Pointer Arithmetic & UB Shao Miller <sha0.miller@gmail.com> - 2012-12-21 17:57 -0500
Re: Pointer Arithmetic & UB glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-21 23:52 +0000
Re: Pointer Arithmetic & UB Shao Miller <sha0.miller@gmail.com> - 2012-12-21 19:47 -0500
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-21 22:54 -0800
Re: Pointer Arithmetic & UB Shao Miller <sha0.miller@gmail.com> - 2012-12-22 03:31 -0500
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-22 09:16 -0800
Re: Pointer Arithmetic & UB Shao Miller <sha0.miller@gmail.com> - 2012-12-24 04:23 -0500
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-27 11:07 -0800
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-17 02:33 -0800
Re: Pointer Arithmetic & UB Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-17 02:18 -0800
Re: Pointer Arithmetic & UB Noob <root@127.0.0.1> - 2012-12-11 11:36 +0100
Re: Pointer Arithmetic & UB "christian.bau" <christian.bau@cbau.wanadoo.co.uk> - 2012-12-11 10:00 -0800
Re: Pointer Arithmetic & UB Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-12-17 12:11 +0200
Re: Pointer Arithmetic & UB Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-12-11 15:27 -0500
Re: Pointer Arithmetic & UB glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-11 21:09 +0000
Re: Pointer Arithmetic & UB Ken Brody <kenbrody@spamcop.net> - 2012-12-12 14:30 -0500
Re: Pointer Arithmetic & UB Keith Thompson <kst-u@mib.org> - 2012-12-12 11:42 -0800
Re: Pointer Arithmetic & UB Ken Brody <kenbrody@spamcop.net> - 2012-12-12 17:12 -0500
Re: Pointer Arithmetic & UB Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-12-17 12:16 +0200
Re: Pointer Arithmetic & UB Prathamesh Kulkarni <bilbotheelffriend@gmail.com> - 2012-12-10 12:04 -0800
Re: Pointer Arithmetic & UB James Kuyper <jameskuyper@verizon.net> - 2012-12-10 15:29 -0500
Re: Pointer Arithmetic & UB Prathamesh Kulkarni <bilbotheelffriend@gmail.com> - 2012-12-10 12:44 -0800
Re: Pointer Arithmetic & UB Prathamesh Kulkarni <bilbotheelffriend@gmail.com> - 2012-12-10 12:47 -0800
Re: Pointer Arithmetic & UB James Kuyper <jameskuyper@verizon.net> - 2012-12-10 16:02 -0500
Re: Pointer Arithmetic & UB Prathamesh Kulkarni <bilbotheelffriend@gmail.com> - 2012-12-10 13:08 -0800
Re: Pointer Arithmetic & UB Ken Brody <kenbrody@spamcop.net> - 2012-12-12 14:26 -0500
Re: Pointer Arithmetic & UB Greg Martin <greg@softsprocket.com> - 2012-12-10 14:55 -0800
Re: Pointer Arithmetic & UB Sjouke Burry <s@b> - 2012-12-10 21:18 +0000
Re: Pointer Arithmetic & UB falk@rahul.net (Edward A. Falk) - 2012-12-11 00:48 +0000
Re: Pointer Arithmetic & UB glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-10 21:01 +0000
Re: Pointer Arithmetic & UB Ken Brody <kenbrody@spamcop.net> - 2012-12-12 14:24 -0500
Re: Pointer Arithmetic & UB Robert Wessel <robertwessel2@yahoo.com> - 2012-12-12 14:34 -0600
Re: Pointer Arithmetic & UB glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-12 20:45 +0000
Re: Pointer Arithmetic & UB Robert Wessel <robertwessel2@yahoo.com> - 2012-12-12 15:29 -0600
Re: Pointer Arithmetic & UB glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-13 02:02 +0000
Re: Pointer Arithmetic & UB Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-12-17 05:57 -0800
Re: Pointer Arithmetic & UB pete <pfiland@mindspring.com> - 2012-12-10 20:20 -0500
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