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Groups > comp.lang.c > #163514
| From | Meredith Montgomery <mmontgomery@levado.to> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' |
| Date | 2021-11-19 18:10 -0300 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <86wnl3kg25.fsf@levado.to> (permalink) |
| References | <86pmqwkm7u.fsf@levado.to> <lk1gpglc7tieirh54eeqdbiujmid08f8ej@4ax.com> |
Barry Schwarz <schwarzb@delq.com> writes: > On Fri, 19 Nov 2021 15:57:09 -0300, Meredith Montgomery > <mmontgomery@levado.to> wrote: > >>I did not get Brian Kernighan's concern with setting EOF to a char c. >>The context is >> >> char c = getchar(); >> >>And Kernighan says: >> >>--8<---------------cut here---------------start------------->8--- >>We must declare c to be a type big enough to hold any value that getchar >>returns. We can't use char since c must be big enough to hold EOF in >>addition to any possible char . Therefore we use int. >>--8<---------------cut here---------------end--------------->8--- >> >>I'm trying to justify this using C99's document. Here's what I find. >> >>--8<---------------cut here---------------start------------->8--- >>Section 6.25 Types >>[...] >> >>3. An object declared as type char is large enough to store any member >>of the basic execution character set. If a member of the basic execution >>character set is stored in a char object, its value is guaranteed to be >>positive. If any other character is stored in a char object, the >>resulting value is implementation-defined but shall be within the range >>of values that can be represented in that type. >>--8<---------------cut here---------------end--------------->8--- >> >>So I can't be sure a char would always be signed, for example. I can't >>be sure EOF would fit in a char. >> >>Am I looking at the right place, thinking the right thing? Thank you. > > Yes., you are. On some systems (for example, on IBM mainframes which > use EBCDIC coding), char is unsigned. Since EOF must be negative, it > would not fit. Thus getchar returns an int. Nice. Thanks very much for the IBM mainframe example.
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K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Meredith Montgomery <mmontgomery@levado.to> - 2021-11-19 15:57 -0300
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-11-19 12:21 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Meredith Montgomery <mmontgomery@levado.to> - 2021-11-19 18:14 -0300
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-11-19 14:10 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Meredith Montgomery <mmontgomery@levado.to> - 2021-11-20 17:30 -0300
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' scott@slp53.sl.home (Scott Lurndal) - 2021-11-21 16:01 +0000
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Philipp Klaus Krause <pkk@spth.de> - 2021-11-22 11:23 +0100
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-11-22 12:55 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Philipp Klaus Krause <pkk@spth.de> - 2021-11-23 17:04 +0100
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-11-23 09:43 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Philipp Klaus Krause <pkk@spth.de> - 2021-11-24 11:26 +0100
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-10 01:41 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' David Brown <david.brown@hesbynett.no> - 2021-12-10 14:40 +0100
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Barry Schwarz <schwarzb@delq.com> - 2021-11-19 12:22 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Meredith Montgomery <mmontgomery@levado.to> - 2021-11-19 18:10 -0300
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' David Brown <david.brown@hesbynett.no> - 2021-11-20 13:24 +0100
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Meredith Montgomery <mmontgomery@levado.to> - 2021-11-20 17:32 -0300
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Mark Bluemel <mark.bluemel@gmail.com> - 2021-11-22 00:27 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Mark Bluemel <mark.bluemel@gmail.com> - 2021-11-22 00:34 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-11-22 02:04 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Mark Bluemel <mark.bluemel@gmail.com> - 2021-11-22 02:46 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-11-22 21:22 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-11-22 22:03 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' scott@slp53.sl.home (Scott Lurndal) - 2021-11-23 14:52 +0000
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Dave Dunfield <dave.dunfield@gmail.com> - 2021-11-26 07:31 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Dave Dunfield <dave.dunfield@gmail.com> - 2021-12-08 07:26 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-08 12:16 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Dave Dunfield <dave.dunfield@gmail.com> - 2021-12-08 18:59 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-08 19:23 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Dave Dunfield <dave.dunfield@gmail.com> - 2021-12-09 06:30 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Manfred <noname@add.invalid> - 2021-12-09 16:10 +0100
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-12-09 16:05 +0000
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Bart <bc@freeuk.com> - 2021-12-09 17:41 +0000
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Dave Dunfield <dave.dunfield@gmail.com> - 2021-12-09 12:24 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-12-09 22:59 +0000
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-12-09 21:26 +0000
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Bart <bc@freeuk.com> - 2021-12-09 22:37 +0000
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-12-09 23:09 +0000
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-10 01:58 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-10 10:46 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-12 08:21 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Paul <nospam@needed.invalid> - 2021-12-09 10:31 -0500
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-12-09 13:32 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' luser droog <luser.droog@gmail.com> - 2021-12-09 17:08 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Dave Dunfield <dave.dunfield@gmail.com> - 2021-12-10 12:45 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Manfred <noname@add.invalid> - 2021-12-11 19:17 +0100
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Bart <bc@freeuk.com> - 2021-12-11 23:19 +0000
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-15 00:31 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Mark Bluemel <mark.bluemel@gmail.com> - 2021-12-09 02:26 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Bart <bc@freeuk.com> - 2021-12-09 11:20 +0000
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Dave Dunfield <dave.dunfield@gmail.com> - 2021-12-09 06:50 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Andrey Tarasevich <andreytarasevich@hotmail.com> - 2021-12-08 20:00 -0800
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' Kaz Kylheku <480-992-1380@kylheku.com> - 2021-12-12 18:55 +0000
Re: K&R, 2nd edition, Brian's concerns with ``char c = EOF'' James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-12-12 14:38 -0500
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