From -2107315184582059508 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,8d9af67f0c48e4ef X-Google-Attributes: gidf78e5,public X-Google-Thread: fc772,8d9af67f0c48e4ef X-Google-Attributes: gidfc772,public X-Google-ArrivalTime: 2002-04-30 09:52:08 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!bloom-beacon.mit.edu!nycmny1-snh1.gtei.net!denver-snf1.gtei.net!news.gtei.net!namche.sun.com!news2me.EBay.Sun.COM!engnews1.eng.sun.com!taumet!clamage From: "P.J. Plauger" Newsgroups: comp.std.c++,comp.lang.c++.moderated Subject: Re: Unsignedness of size_t Date: 29 Apr 2002 21:49:25 GMT Organization: unknown Lines: 62 Approved: stephen.clamage@sun.com (comp.std.c++) Message-ID: <3ccd58e5$0$20934$4c41069e@reader1.ash.ops.us.uu.net> References: <3CC7DB8F.52E75D62@bawi.org> NNTP-Posting-Host: taumet.eng.sun.com X-NNTP-Posting-Host: netlab.cs.rpi.edu X-Original-Date: Mon, 29 Apr 2002 10:30:19 -0400 X-Submission-Address: c++-submit@netlab.cs.rpi.edu X-Auth: PGPMoose V1.1 PGP comp.lang.c++.moderated iQBVAwUAPM22kEHMCo9UcraBAQFMQQIAjxR5Two3kfP9u2xijvH69lLZpjJVyM6z jqVaQxo38DCJMBq/QS8+FjrFYRPWx704PqKrJMkX3ox50zxsZgnh5Q== =ryBH X-Approved-For-Group: jep@[151.161.11.6] comp.lang.c++.moderated X-Scanned-By: MIMEDefang 2.3 (www dot roaringpenguin dot com slash mimedefang) Content-Length: 2390 X-Status: $$$$ Originator: clamage@taumet Xref: archiver1.google.com comp.std.c++:10905 comp.lang.c++.moderated:42394 "Sungbom Kim" wrote in message news:3CC7DB8F.52E75D62@bawi.org... > I often find it somewhat "flawed" that the standard requires the data > type representing sizes of objects to be an unsigned integral type. I don't. > They are just arithmetic quantities, like 'number of people'; no one > would recommend using unsigned numbers for those kind of quantities. Really? I would. And I usually do, in my own code. > They have semantics of neither modular arithmetics nor bit arrays. > As Stroustrup mentioned in TC++PL 4.4, usage of unsigned integer types > for that kind of situation is discouraged. By whom? Not by me. > It also causes many problems > in arithmetics mixed with signed integers. It is true that ``unsigned'' in C/C++ is really modulus arithmetic. Since neither language has a non-negative type, unsigned is the closest you can get. Indeed, I usually find it a better match than signed. Since the C Standard chose value-preserving promotion rules over unsigned-preserving, I have had few occasions where mixed arithmetic causes any real problems. The usual problem I see is busybody compilers that insist on warning that an operation *might* be dangerous -- the problem is that I have to add type casts to avoid customer complaints about warning messages. Java chose to deep six all the unsigned types. As a result, I've had to play ugly games in several places when writing the Java library. When you need unsigned arithmetic, you really need it. > I know that it is from C and that it's too late to change anything, > but I just want to hear what others have to say. You just did. In fairness, I have to confess that I'm the person who proposed the introduction of size_t as an unsigned type into Standard C. And I also fought hard for the VP rules over UP ones. So I'm doubtless biased in this area. P.J. Plauger Dinkumware, Ltd. http://www.dinkumware.com [ Send an empty e-mail to c++-help@netlab.cs.rpi.edu for info ] [ about comp.lang.c++.moderated. First time posters: do this! ] [ 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://www.jamesd.demon.co.uk/csc/faq.html ]