Article View: comp.std.c++
Article #3768Re: Referencing pointers after delete
From: joe (j.) halpin
Date: Fri, 22 Mar 1996 02:02
Date: Fri, 22 Mar 1996 02:02
49 lines
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2358 bytes
In article <4isca2$t20@news.BelWue.DE>, Dietmar Kuehl <dietmar.kuehl@uni-konstanz.de> wrote: >Hi, > >joe (j.) halpin (jhalpin@bnr.ca) wrote: >: In 3.7.3.2.4 the January working paper says: > >: 4 A deallocation function can free the storage referenced by the pointer >: given as its argument and renders the pointer invalid. The storage >: can be made available for further allocation. An invalid pointer con- >: tains an unusable value: it cannot even be used in an expression. > >: This sounds as though, in the following: > >: char *pc = new char[128]; >: delete pc; >: pc = 0; > >: it makes the final assignment (an expression) invalid. > >No. You cannot use the value of the pointer but you can use the pointer So, in the sentence above - "An invalid pointer contains an unusable value: it cannot even be used in an expression." - the word 'it' refers to the value and not the pointer? That makes sense, although the phrasing is a bit ambiguous. >(actually, you get undefined behavior in the code above because you >delete an array object with 'delete' instead of 'delete[]'; I assume Mea culpa. [...] Thanks Joe -- Joe Halpin jhalpin@nortel.com Nortel Wireless (214) 684-5657 Richardson, TX 75083-3871 <standard disclaimer applies> ------------------------------------------------------------------------------- --- [ comp.std.c++ is moderated. To submit articles: try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ FAQ: http://reality.sgi.com/employees/austern_mti/std-c++/faq.html ] [ Policy: http://reality.sgi.com/employees/austern_mti/std-c++/policy.html ] [ Comments? mailto:std-c++-request@ncar.ucar.edu ]
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From: "joe (j.) halpin" <jhalpin@bnr.ca> Message-ID: <4iss70$82f@crchh327.rich.bnr.ca> X-Original-Date: Fri, 22 Mar 1996 00:28:16 +0000 Path: arc1-ca.pugleaf.net!in2.uu.net!bounce-back Date: 22 Mar 96 02:02:01 GMT Approved: fjh@cs.mu.oz.au Subject: Re: Referencing pointers after delete Newsgroups: comp.std.c++ Organization: Bell-Northern Research, Richardson, TX X-Auth: PGPMoose V1.1 PGP comp.std.c++ iQBFAgUBMVIKSuEDnX0m9pzZAQGFNAF9FadegeWAJQ5D0E/0lNpBKRJAL1/NyKfk 5n5fa96+ZbiBSwHSh8g2P+JvoduVpHXk =de/9