Article View: comp.std.c++
Article #3760Using pointers after delete
From: joe (j.) halpin
Date: Thu, 21 Mar 1996 19:08
Date: Thu, 21 Mar 1996 19:08
36 lines
2153 bytes
2153 bytes
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.
Am I misunderstanding something, or is it illegal to zero out pointers
after they've been deallocated? I'm assuming that the intent was to
disallow dereferencing of pointers that have been handed to
delete. The wording seems to disallow the above as well.
In fact, it sounds like it also rules out things like 'if(pc == 0)
...' after the above fragment.
Joe
--
Joe Halpin jhalpin@nortel.com
Nortel Wireless (214) 684-5657
Richardson, TX 75083-3871 <standard disclaimer applies>
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Path: arc1-ca.pugleaf.net!chronicle.mti.sgi.com!austern From: "joe (j.) halpin" <jhalpin@bnr.ca> Newsgroups: comp.std.c++ Subject: Using pointers after delete Date: 21 Mar 1996 11:08:42 PST Organization: Bell-Northern Research, Richardson, TX Approved: austern@isolde.mti.sgi.com Message-ID: <4irkhs$8al@crchh327.rich.bnr.ca> NNTP-Posting-Host: isolde.mti.sgi.com X-Original-Date: Thu, 21 Mar 1996 13:11:24 +0000 Content-Identifier: Using pointer... X-Auth: PGPMoose V1.1 PGP comp.std.c++ iQBVAwUBMVGpm0y4NqrwXLNJAQGtpgIAgXYveU7qMkMyxwlfi0myt0w5NTDN9qFP RL+AcDtiraLG5Gvnj6QZFofuVOyC4kdHyPTm158EIKiQuKiAvGA3YA== =0mMj Originator: austern@isolde.mti.sgi.com