Article View: comp.std.c
Article #537Re: ANSI C, hardware protection, out-of-bounds pointers
From: Joseph S. D. Yao
Date: Thu, 07 Sep 1989 03:45
Date: Thu, 07 Sep 1989 03:45
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1077 bytes
In article <427@maytag.waterloo.edu> lhf@aries5 (Luiz H. deFigueiredo) writes: -ANSI C says that is *is* legal to use mention (but not dereference) a pointer -just out-of-bounds as in - - char a[N]; - char *last=a+N; /* Here! */ - char *p; - for (p=a; p<last; p++) -Now I ask, it is possible/legal to do the analogous thing for a-1 as in - char *head=a-1; /* Here! */ - for (p=last-1; p>head; p--) This, too, is an out-of-bounds pointer, and is covered by the same rule. Nothing says that an OOB ptr has to be positively offset. joe yao
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arc1-ca.pugleaf.net!utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!mailrus!purdue!decwrl!shlump.nac.dec.com!decuac!hadron!jsdyReferences:
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!mailrus!purdue!decwrl!shlump.nac.dec.com!decuac!hadron!jsdy From: jsdy@hadron.UUCP (Joseph S. D. Yao) Newsgroups: comp.std.c Subject: Re: ANSI C, hardware protection, out-of-bounds pointers Keywords: ANSI C, hardware protection, out-of-bounds pointers Message-ID: <867@hadron.UUCP> Date: 7 Sep 89 03:45:27 GMT References: <427@maytag.waterloo.edu> Reply-To: jsdy@hadron.UUCP (Joseph S. D. Yao) Organization: Hadron, Inc., Fairfax, VA Lines: 16