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Groups > comp.lang.c > #110976
| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: C Macros Badly Defined? |
| Date | 2017-05-30 16:03 -0700 |
| Organization | None to speak of |
| Message-ID | <lnfufmq75f.fsf@kst-u.example.com> (permalink) |
| References | (11 earlier) <kfna85uebdg.fsf@x-alumni2.alumni.caltech.edu> <dd7db285-dbdc-4045-9b78-d742c677b123@googlegroups.com> <20170530191233.84e5575b78503611c757e526@gmail.com> <24fcaf3b-5a4a-46ad-ad65-ad7ab3e23c66@googlegroups.com> <dac46230-cfd9-4370-9f02-e4bb3e640a3d@googlegroups.com> |
supercat@casperkitty.com writes:
> On Tuesday, May 30, 2017 at 4:56:03 PM UTC-5, David Kleinecke wrote:
>> My biggest bitch with the Standards is that they use the
>> modal verb "shall" is an un-English way (which might be a
>> legalism). In fact, the modal "shall" has, these days,
>> disappeared from all but the most old-fashioned pedantic
>> English.
>
> That is a pretty severe problem.
No, it isn't.
> In most cases where a standard says that
> a conforming widget MUST do X, that implies that anything which does not do
> X is, *by definition*, not a conforming widget. The C Standard, however,
> uses the term "shall" in some cases where it means nothing beyond the fact
> that:
>
> 1. A program that fails to do what is specified is not strictly conforming.
>
> 2. The Standard does not require that conforming implementations behave
> in any particular fashion if programs fail to do what is specified.
The term, as you know, is "undefined behavior". Hiding it behind extra
wording is not helpful.
The C standard defines clearly and unambiguously what it means by
"shall". The meaning depends on the context; it means one thing in a
constraint, and something else outside a constraint.
> Note that if it would make sense for most implementations to process some
> action the same way (e.g. the way it was defined in C89) but there might
> possibly be some platforms where defining a consistent behavior would be
> expensive (e.g. ones'-complement machines), leaving the behavior Undefined
> should allow implementations to process such actions sensibly.
Leaving the behavior undefined quite literally allows implementations to
behave in any way they like, including whatever you think is sensible.
> All that's
> necessary is that implementers recognize that (1) there is significant
> value in following precedent absent a compelling reason to do otherwise,
> and (2) permission to do otherwise does not, in and of itself, constitute
> a compelling reason.
Do you really have a problem with the way the standard uses the word "shall"?
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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Re: C Macros Badly Defined? Tim Rentsch <txr@alumni.caltech.edu> - 2017-05-24 08:16 -0700
Re: C Macros Badly Defined? supercat@casperkitty.com - 2017-05-24 10:43 -0700
Re: C Macros Badly Defined? Ike Naar <ike@iceland.freeshell.org> - 2017-05-24 19:06 +0000
Re: C Macros Badly Defined? Tim Rentsch <txr@alumni.caltech.edu> - 2017-05-27 06:10 -0700
Re: C Macros Badly Defined? David Kleinecke <dkleinecke@gmail.com> - 2017-05-27 12:02 -0700
Re: C Macros Badly Defined? supercat@casperkitty.com - 2017-05-27 13:42 -0700
Re: C Macros Badly Defined? David Kleinecke <dkleinecke@gmail.com> - 2017-05-27 15:48 -0700
Re: C Macros Badly Defined? supercat@casperkitty.com - 2017-05-28 14:40 -0700
Re: C Macros Badly Defined? Tim Rentsch <txr@alumni.caltech.edu> - 2017-05-29 08:33 -0700
Re: C Macros Badly Defined? Tim Rentsch <txr@alumni.caltech.edu> - 2017-05-29 08:17 -0700
Re: C Macros Badly Defined? bartc <bc@freeuk.com> - 2017-05-29 16:26 +0100
Re: C Macros Badly Defined? Tim Rentsch <txr@alumni.caltech.edu> - 2017-05-30 06:13 -0700
Re: C Macros Badly Defined? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-05-30 09:57 -0700
Re: C Macros Badly Defined? GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-05-30 19:12 +0200
Re: C Macros Badly Defined? David Kleinecke <dkleinecke@gmail.com> - 2017-05-30 14:55 -0700
Re: C Macros Badly Defined? supercat@casperkitty.com - 2017-05-30 15:39 -0700
Re: C Macros Badly Defined? Keith Thompson <kst-u@mib.org> - 2017-05-30 16:03 -0700
Re: C Macros Badly Defined? supercat@casperkitty.com - 2017-05-30 16:50 -0700
Re: C Macros Badly Defined? Keith Thompson <kst-u@mib.org> - 2017-05-30 17:12 -0700
Re: C Macros Badly Defined? supercat@casperkitty.com - 2017-05-31 06:30 -0700
Re: C Macros Badly Defined? Keith Thompson <kst-u@mib.org> - 2017-05-31 09:36 -0700
Re: C Macros Badly Defined? David Kleinecke <dkleinecke@gmail.com> - 2017-05-31 12:08 -0700
Re: C Macros Badly Defined? scott@slp53.sl.home (Scott Lurndal) - 2017-05-31 19:16 +0000
Re: C Macros Badly Defined? David Kleinecke <dkleinecke@gmail.com> - 2017-05-31 12:35 -0700
Re: C Macros Badly Defined? Tim Rentsch <txr@alumni.caltech.edu> - 2017-06-01 04:06 -0700
Re: C Macros Badly Defined? David Kleinecke <dkleinecke@gmail.com> - 2017-06-01 10:33 -0700
Re: C Macros Badly Defined? Keith Thompson <kst-u@mib.org> - 2017-06-01 12:00 -0700
Re: C Macros Badly Defined? David Kleinecke <dkleinecke@gmail.com> - 2017-06-01 15:35 -0700
Re: C Macros Badly Defined? Keith Thompson <kst-u@mib.org> - 2017-06-01 17:26 -0700
Re: C Macros Badly Defined? David Kleinecke <dkleinecke@gmail.com> - 2017-06-01 20:48 -0700
Re: C Macros Badly Defined? Keith Thompson <kst-u@mib.org> - 2017-05-31 12:43 -0700
Re: C Macros Badly Defined? David Kleinecke <dkleinecke@gmail.com> - 2017-05-31 21:50 -0700
Re: C Macros Badly Defined? raltbos@xs4all.nl (Richard Bos) - 2017-06-03 11:36 +0000
Re: C Macros Badly Defined? gazelle@shell.xmission.com (Kenny McCormack) - 2017-06-03 11:44 +0000
Re: C Macros Badly Defined? Keith Thompson <kst-u@mib.org> - 2017-06-03 09:19 -0700
Re: C Macros Badly Defined? gazelle@shell.xmission.com (Kenny McCormack) - 2017-06-03 16:22 +0000
Re: Standards in various formats Noob <root@127.0.0.1> - 2017-06-01 13:24 +0200
Re: C Macros Badly Defined? jadill33@gmail.com - 2017-05-31 13:02 -0700
Re: C Macros Badly Defined? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-05-30 22:06 -0700
Re: C Macros Badly Defined? David Brown <david.brown@hesbynett.no> - 2017-05-31 12:51 +0200
Re: C Macros Badly Defined? supercat@casperkitty.com - 2017-05-31 06:21 -0700
Re: C Macros Badly Defined? David Brown <david.brown@hesbynett.no> - 2017-05-31 17:16 +0200
Re: C Macros Badly Defined? GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-05-31 17:24 +0200
Re: C Macros Badly Defined? "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-05-31 22:18 +0200
Re: C Macros Badly Defined? GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-05-31 23:09 +0200
Re: C Macros Badly Defined? Jerry Stuckle <jstucklex@attglobal.net> - 2017-05-31 17:32 -0400
Re: C Macros Badly Defined? GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-05-31 23:50 +0200
Re: C Macros Badly Defined? Jerry Stuckle <jstucklex@attglobal.net> - 2017-05-31 18:01 -0400
Re: C Macros Badly Defined? GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-06-01 00:33 +0200
Re: C Macros Badly Defined? Jerry Stuckle <jstucklex@attglobal.net> - 2017-05-31 22:36 -0400
Re: C Macros Badly Defined? GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-06-01 06:08 +0200
Re: C Macros Badly Defined? Jerry Stuckle <jstucklex@attglobal.net> - 2017-06-01 11:08 -0400
Re: C Macros Badly Defined? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-06-01 01:30 -0700
Re: C Macros Badly Defined? GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-06-01 11:38 +0200
Re: C Macros Badly Defined? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-06-01 03:13 -0700
Re: C Macros Badly Defined? GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-06-01 12:25 +0200
Re: C Macros Badly Defined? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-06-01 04:48 -0700
Re: C Macros Badly Defined? GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-06-01 14:27 +0200
Re: C Macros Badly Defined? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-06-01 05:55 -0700
Re: C Macros Badly Defined? Jerry Stuckle <jstucklex@attglobal.net> - 2017-06-01 11:11 -0400
Re: C Macros Badly Defined? GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-06-01 17:40 +0200
Re: C Macros Badly Defined? Ian Collins <ian-news@hotmail.com> - 2017-06-02 08:32 +1200
Re: C Macros Badly Defined? GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-06-01 23:14 +0200
Re: C Macros Badly Defined? jameskuyper@verizon.net - 2017-06-01 14:41 -0700
Re: C Macros Badly Defined? Ian Collins <ian-news@hotmail.com> - 2017-06-02 09:48 +1200
Re: C Macros Badly Defined? David Brown <david.brown@hesbynett.no> - 2017-06-02 00:56 +0200
Re: C Macros Badly Defined? Ian Collins <ian-news@hotmail.com> - 2017-06-02 11:12 +1200
Re: C Macros Badly Defined? raltbos@xs4all.nl (Richard Bos) - 2017-06-03 11:54 +0000
Re: C Macros Badly Defined? Leon Taylor <leontaylor476@gmail.com> - 2017-06-03 05:10 -0700
Re: C Macros Badly Defined? David Brown <david.brown@hesbynett.no> - 2017-06-04 14:32 +0200
Re: C Macros Badly Defined? Melzzzzz <Melzzzzz@zzzzz.com> - 2017-06-01 21:44 +0000
Re: C Macros Badly Defined? raltbos@xs4all.nl (Richard Bos) - 2017-06-03 11:51 +0000
Re: C Macros Badly Defined? gazelle@shell.xmission.com (Kenny McCormack) - 2017-06-01 21:38 +0000
Re: C Macros Badly Defined? Ian Collins <ian-news@hotmail.com> - 2017-06-02 11:10 +1200
Re: C Macros Badly Defined? gazelle@shell.xmission.com (Kenny McCormack) - 2017-06-01 23:34 +0000
Re: C Macros Badly Defined? raltbos@xs4all.nl (Richard Bos) - 2017-06-03 11:48 +0000
Re: C Macros Badly Defined? supercat@casperkitty.com - 2017-06-01 08:56 -0700
Re: C Macros Badly Defined? David Brown <david.brown@hesbynett.no> - 2017-06-02 14:11 +0200
Re: C Macros Badly Defined? supercat@casperkitty.com - 2017-06-02 10:02 -0700
Re: C Macros Badly Defined? raltbos@xs4all.nl (Richard Bos) - 2017-06-03 11:45 +0000
Re: C Macros Badly Defined? Keith Thompson <kst-u@mib.org> - 2017-05-31 09:11 -0700
Re: C Macros Badly Defined? raltbos@xs4all.nl (Richard Bos) - 2017-06-03 11:29 +0000
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