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Groups > comp.lang.c > #110978

Re: C Macros Badly Defined?

From Keith Thompson <kst-u@mib.org>
Newsgroups comp.lang.c
Subject Re: C Macros Badly Defined?
Date 2017-05-30 17:12 -0700
Organization None to speak of
Message-ID <lnbmq9rijy.fsf@kst-u.example.com> (permalink)
References (13 earlier) <20170530191233.84e5575b78503611c757e526@gmail.com> <24fcaf3b-5a4a-46ad-ad65-ad7ab3e23c66@googlegroups.com> <dac46230-cfd9-4370-9f02-e4bb3e640a3d@googlegroups.com> <lnfufmq75f.fsf@kst-u.example.com> <ce4d2265-c85d-4944-855e-19a2d9b55fa5@googlegroups.com>

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supercat@casperkitty.com writes:
> On Tuesday, May 30, 2017 at 6:03:48 PM UTC-5, Keith Thompson wrote:
>> The term, as you know, is "undefined behavior".  Hiding it behind extra
>> wording is not helpful.
>
> Many useful tasks cannot be performed efficiently, or at all, without using
> behaviors which are defined by some implementations but are not mandated by 
> the Standard.  What terminology would you use to distinguish those behaviors
> from behaviors which are not defined by anything whatsoever?

"Non-portable", I suppose.

> The fact that programs which invoke upon not-defined-by-anything behaviors
> are broken does not imply that programs which invoke not-defined-by-the-
> Standard-but-instead-defined-by-other-things behaviors are broken.  Some
> compiler writers seem unable to distinguish those categories, however.

Feel free to complain to them.

>> 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.
>
> Most standards specify what conforming entities have to "do", and are quite
> specific about what entities are responsible for ensuring what.  The Standard
> sometimes talks about obligations of programs or implementations, but
> sometimes uses "shall be" to impose obligations upon grammatical constructs.

For example?

[...]

-- 
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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Thread

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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