From 1988143095130126321 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: 2002-05-03 07:42:08 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!bloom-beacon.mit.edu!nycmny1-snh1.gtei.net!cpk-news-hub1.bbnplanet.com!denver-snf1.gtei.net!news.gtei.net!namche.sun.com!sunnews1.Eng.Sun.COM!engnews1.eng.sun.com!taumet!clamage From: Francis Glassborow Newsgroups: comp.std.c++,comp.lang.c++.moderated Subject: Re: Unsignedness of size_t Date: 3 May 2002 14:37:50 GMT Organization: Southfield Microcomputer SS Lines: 53 Approved: stephen.clamage@sun.com (comp.std.c++) Message-ID: References: <3CC7DB8F.52E75D62@bawi.org> <1020129034.890475@cswreg.cos.agilent.com> Reply-To: Francis Glassborow NNTP-Posting-Host: taumet.eng.sun.com X-NNTP-Posting-Host: netlab.cs.rpi.edu X-Original-Date: Thu, 2 May 2002 13:24:23 +0100 X-Submission-Address: c++-submit@netlab.cs.rpi.edu X-Auth: PGPMoose V1.1 PGP comp.lang.c++.moderated iQBVAwUAPNG4DEHMCo9UcraBAQHfkAIAnGW+QgTxLyNUW2B36jrsTiUoagn339/A GKErywf0PseK7Ma4a7qWuz6vBBoOzqiEl4tvLxziLdkkhGZ0zgi0zg== =7NUq 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: 2326 X-Status: $$$T X-UID: 0000000001 Originator: clamage@taumet Xref: archiver1.google.com comp.std.c++:11007 comp.lang.c++.moderated:42589 In article <1020129034.890475@cswreg.cos.agilent.com>, Geoff Field writes >> They are just arithmetic quantities, like 'number of people'; no one >> would recommend using unsigned numbers for those kind of quantities. > >Why not? Can one have *negative* numbers of people, or negative sizes? >To my mind, unsigned integral types are the most natural model of a >count of anything "real" - be it people, bytes or bits. Sure, they are fine for counting. However in a world where only unsigned values were used (before mathematicians invented negative numbers) subtracting a larger number from a smaller one 'failed', it did not generate a ridiculously large answer. Trying to use a negative value for an unsigned type should raise an exception. > >Apart from that, unsigned types on most platforms have an extra bit >available for counting before going to the next size up. This may not >matter in the hosted world, but for us embedded folks it usually means >adding lots of overhead to drag in another library or set of routines to >handle the bigger data type. But in the world of embedded coding there are many other restraints. Anyone who jumps into that world without doing some form of conversion course (if only careful study in private) will write poor code. The requirements of embedded coding are special and should not be imposed on everyone. I have no problem with unsigned integer types per se. I have a big problem with being forced to use them or to use casts to remove them. I think size_t is wrongly specified, and I think time_t and clock_t are underspecified (if you use either of those in arithmetic you have the problem that they may be any arithmetic type.) -- Francis Glassborow ACCU 64 Southfield Rd Oxford OX4 1PA +44(0)1865 246490 All opinions are mine and do not represent those of any organisation [ 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 ]