printf Conversions) Both Tanmoy Bhattacharya and Dan Pop pointed out a mistake in Table B-1 (on p. 244)
about printf conversions. Tanmoy provided a citation to the standard. Dan explained where the confusion may have come from.
Newsgroups: comp.lang.c From: Tanmoy Bhattacharya <tanmoy@qcd.lanl.gov> Subject: Re: Posted code MUST compile Date: 14 Feb 1997 14:35:43 -0700 Organization: Los Alamos National Laboratory Lines: 37 Distribution: inet Message-ID: <y84tff840g.fsf@qcd.lanl.gov> References: <5dqsbs$i8j$3@brokaw.wa.com> <5dvbli$6ma@news1.mnsinc.com> <y8hgjg8bih.fsf@qcd.lanl.gov> <5e259b$4mg@hnssysb.hns.com> X-Newsreader: Gnus v5.3/Emacs 19.34 sthuang@hns.com (Steven Huang) writes: <snip> > >> Eh? The %x format displays its 'int' parameter in unsigned > > ^^^ > >unsigned int according to the standard. > > I thought so, too. Table B-1 of K&R2 (where I copied from) however said > 'int', converted to unsigned hexadecimal notation. My manpage said: > > d,i,o,u,x,X The integer arg is converted to signed decimal (d > and i are identical), unsigned octal (o), decimal > (u), or hexadecimal notation (x and X), respectively; > > I think we need a lawyer now. :) No, the standard is at hand, and clearly states that it is undigned int: d,i The int argument .... o,u,x,X The unsigned int argument ... (7.9.6.1) I vaguely remember there was a defect report that the standard fails to mention that not passing the `correct' type leads to undefined behaviour and the committee clarified that it was indeed undefined, but I am sure c.l.c is not the right place for nit picks at that level. Cheers Tanmoy -- tanmoy@qcd.lanl.gov(128.165.23.46) DECNET: BETA::"tanmoy@lanl.gov"(1.218=1242) Tanmoy Bhattacharya O:T-8(MS B285)LANL,NM87545 H:#9,3000,Trinity Drive,NM87544 Others see <gopher://yaleinfo.yale.edu:7700/00/Internet-People/internet-mail>, <http://alpha.acast.nova.edu/cgi-bin/inmgq.pl>or<ftp://csd4.csd.uwm.edu/pub/ internetwork-mail-guide>. -- <http://nqcd.lanl.gov/people/tanmoy/tanmoy.html> fax: 1 (505) 665 3003 voice: 1 (505) 665 4733 [ Home: 1 (505) 662 5596 ]
Newsgroups: comp.lang.c From: Dan.Pop@cern.ch (Dan Pop) Subject: Re: Posted code MUST compile Message-ID: <danpop.855943185@news.cern.ch> Sender: news@news.cern.ch (USENET News System) Organization: CERN European Lab for Particle Physics X-Newsreader: NN version 6.5.0 #18 (NOV) References: <5dqsbs$i8j$3@brokaw.wa.com> <5dvbli$6ma@news1.mnsinc.com> <y8hgjg8bih.fsf@qcd.lanl.gov> <5e259b$4mg@hnssysb.hns.com> Distribution: inet Date: Fri, 14 Feb 1997 17:59:45 GMT Lines: 36 In <5e259b$4mg@hnssysb.hns.com> sthuang@hns.com (Steven Huang) writes: >In article <y8hgjg8bih.fsf@qcd.lanl.gov> Tanmoy Bhattacharya <tanmoy@qcd.lanl.gov> writes: >>huang@mnsinc.com (Szu-Wen Huang) writes: > >>> Eh? The %x format displays its 'int' parameter in unsigned >> ^^^ >>unsigned int according to the standard. > >I thought so, too. Table B-1 of K&R2 (where I copied from) however said >'int', converted to unsigned hexadecimal notation. My manpage said: > > d,i,o,u,x,X The integer arg is converted to signed decimal (d > and i are identical), unsigned octal (o), decimal > (u), or hexadecimal notation (x and X), respectively; > >I think we need a lawyer now. :) No need for a lawyer, the standard is right, by definition, even when it's wrong :-) The origin of the confusion has to be searched in the history of the standard itself. As late as 1988 (i.e. by the time K&R2 was printed) the draft said: d, i, o, u, x, X The int argument is converted to signed decimal (d or i), unsigned octal (o), unsigned decimal (u), or unsigned hexadecimal notation (x or X); ... Dan -- Dan Pop CERN, IT Division Email: Dan.Pop@cern.ch Mail: CERN - PPE, Bat. 31 1-014, CH-1211 Geneve 23, Switzerland