Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.lang.c > #112074
| From | David Brown <david.brown@hesbynett.no> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Arrays sorting!! |
| Date | 2017-06-12 21:22 +0200 |
| Organization | A noiseless patient Spider |
| Message-ID | <ohmpff$vch$1@dont-email.me> (permalink) |
| References | <ohl2ii$b85$2@gioia.aioe.org> <54a4187b-61cc-4acb-b71c-4a3021d54405@googlegroups.com> <BRv%A.173442$6r7.45165@fx34.am4> <U4w%A.40744$9M.16883@fx18.am4> <6681ba5c-0f02-40f2-9381-13c254b01843@googlegroups.com> |
On 12/06/17 16:36, supercat@casperkitty.com wrote: > On Monday, June 12, 2017 at 7:49:00 AM UTC-5, Bart wrote: >> On second thoughts, that might not matter. The array access can be well >> in bounds, but it's using an element that is not initialised. > > Under C11, if an automatic-duration object is not initialized but its address > is taken, and if the type is one without any trap representations, conforming > implementations are required to ensure that reading the variable will yield > some (possibly arbitrary) value of that type. > 6.7.9 (Initialization): "If an object that has automatic storage duration is not initialized explicitly, its value is indeterminate." Annex J.2 has a list of undefined behaviour, including: "the value of an object with automatic storage duration is used while it is indeterminate (6.2.4, 6.7.9, 6.8)." To me, that sounds like using the value of an uninitialised automatic storage object, before it has been written, is undefined behaviour. This appears to be the case whether you read it directly, or if you take a pointer and read through that. Can you give the reference in C11 for your interpretation of something different?
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Arrays sorting!! Christopher <info@invalid.invalid> - 2017-06-12 04:55 +0100
Re: Arrays sorting!! luser droog <luser.droog@gmail.com> - 2017-06-11 21:30 -0700
Re: Arrays sorting!! bartc <bc@freeuk.com> - 2017-06-12 13:32 +0100
Re: Arrays sorting!! bartc <bc@freeuk.com> - 2017-06-12 13:48 +0100
Re: Arrays sorting!! supercat@casperkitty.com - 2017-06-12 07:36 -0700
Re: Arrays sorting!! David Brown <david.brown@hesbynett.no> - 2017-06-12 21:22 +0200
Re: Arrays sorting!! supercat@casperkitty.com - 2017-06-12 14:00 -0700
Re: Arrays sorting!! David Brown <david.brown@hesbynett.no> - 2017-06-12 23:39 +0200
Re: Arrays sorting!! "James R. Kuyper" <jameskuyper@verizon.net> - 2017-06-12 18:47 -0400
Re: Arrays sorting!! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-12 12:03 +0100
Re: Arrays sorting!! "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2017-06-12 20:23 +0800
Re: Arrays sorting!! mark.bluemel@gmail.com - 2017-06-12 07:32 -0700
Re: Arrays sorting!! "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2017-06-12 23:06 +0800
Re: Arrays sorting!! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-12 16:08 +0100
Re: Arrays sorting!! "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2017-06-12 23:11 +0800
Re: Arrays sorting!! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-12 16:46 +0100
Re: Arrays sorting!! "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2017-06-13 17:49 +0800
Re: Arrays sorting!! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-06-12 15:57 +0100
Re: Arrays sorting!! Real Troll <Real.Troll@Trolls.com> - 2017-06-12 16:55 -0400
csiph-web