From -4631092678261732002 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,fbd36da46c3cc7a0 X-Google-Attributes: gidf78e5,public From: Francis Glassborow Subject: Re: Discussion: type_info Date: 1999/12/08 Message-ID: #1/1 X-Deja-AN: 557940484 Distribution: you Approved: stephen.clamage@sun.com (comp.std.c++) References: <81ecdl$pq$1@nnrp1.deja.com> <81u646$kln$1@nnrp1.deja.com> <823n5t$7qg@library1.airnews.net> <384BBE4F.ABDC393C@lucent.com> <7QYbIRArmTT4Ew2J@robinton.demon.co.uk> <82ju8c$jbf$1@oak.prod.itd.earthlink.net> X-UID: 0000000001 X-Status: $$$T Organization: Southfield Microcomputer SS Mime-Version: 1.0 Reply-To: Francis Glassborow Newsgroups: comp.std.c++ Originator: clamage@taumet In article <82ju8c$jbf$1@oak.prod.itd.earthlink.net>, AllanW writes >AFAIK, any system that has a many-to-one relationship between pointers >and addresses also has some concept that I'll call "normalization" which >is already used when comparing two pointers for equality. This is by >definition platform-dependant, so we can't give out algorithms, but we >can give an example: > > Change the bit pattern so that when it is interpreted as a pointer, the > address does not change, but when it is interpreted as an integer, the > value is lower. Continue until this change is no longer possible, and > then the bit pattern represents the normalized value. > >Naturally, for any real platform there will be equivalent algorithms that >do not involve iteration. There is no problem with comparing pointers for equality (even without normalisation) however requiring that less than shall always 'work' is requiring a complete ordering of addresses and that is something else. > Francis Glassborow Journal Editor, Association of C & C++ Users 64 Southfield Rd Oxford OX4 1PA +44(0)1865 246490 All opinions are mine and do not represent those of any organisation [ 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 ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://reality.sgi.com/austern_mti/std-c++/faq.html ]