Re: pointers

From	Tim Rentsch <txr@alumni.caltech.edu>
Newsgroups	comp.lang.c
Subject	Re: pointers
Date	2016-10-25 08:56 -0700
Organization	A noiseless patient Spider
Message-ID	<kfnfunkwhfw.fsf@x-alumni2.alumni.caltech.edu> (permalink)
References	(5 earlier) <ln7f8yd20j.fsf@kst-u.example.com> <nukp62$tfg$1@dont-email.me> <ba27dbcd-c6c2-4954-aa9a-6e1c54fab1a4@googlegroups.com> <kfn1sz5xxyt.fsf@x-alumni2.alumni.caltech.edu> <lnh981a0fl.fsf@kst-u.example.com>

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Keith Thompson <kst-u@mib.org> writes:

> Tim Rentsch <txr@alumni.caltech.edu> writes:
>> supercat@casperkitty.com writes:
>>> The Standard does [say] that no conforming extension should alter
>>> the effect of a strictly-conforming program, but many of the
>>> "Common Extensions" listed in the annex would do precisely that.
>>
>> That depends on how the extension is implemented, doesn't it?  Or
>> are you saying that some of the listed common extensions would be
>> impossible to implement without changing some strictly conforming
>> programs?  If so, which of the listed extensions fall into that
>> category?
>
> The "fortran" and "asm" keywords, if they're treated as keywords in
> all contexts, would clearly break strictly conforming programs that
> use them as identifiers (J.5.9, J.5.10).

Sure.  If treated as keywords in the same way that regular C
keywords are treated, then yes.  If instead they were treated as
some form of optional, context-dependent keywords, then they
wouldn't necessarily intrude on the strictly-conformingness
property - right?

> Likewise for predefined
> macro names using unreserved identifers (J.5.12).

In this case too I believe it is possible to implement some form
of "weak" macro definitions that would not intrude on the
strictly-conformingness property.  I admit that it's harder to do
that with macros than the previous case.  But there is another
point worth mentioning here:  the offending macro definitions may
be in force only when the compilation is already in some sort of
non-conforming mode.  In gcc, for example, there are predefined
macros such as 'unix', but these predefined macros go away when
an option like -std=c99 or -ansi is used.  So the objection is
very likely not strictly correct, but even in cases where it
applies it seems to be vastly overblown.

Thread

pointers asetofsymbols@gmail.com - 2016-10-23 08:11 -0700
  Re: pointers Richard Heathfield <rjh@cpax.org.uk> - 2016-10-23 16:26 +0100
    Re: pointers asetofsymbols@gmail.com - 2016-10-23 10:35 -0700
      Re: pointers Ike Naar <ike@iceland.freeshell.org> - 2016-10-23 17:47 +0000
        Re: pointers asetofsymbols@gmail.com - 2016-10-25 12:55 -0700
      Re: pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2016-10-23 13:58 -0400
        Re: pointers BartC <bc@freeuk.com> - 2016-10-24 00:55 +0100
          Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-23 17:27 -0700
            Re: pointers BartC <bc@freeuk.com> - 2016-10-24 11:53 +0100
              Re: pointers supercat@casperkitty.com - 2016-10-24 07:29 -0700
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 08:55 -0700
                Re: pointers Tim Rentsch <txr@alumni.caltech.edu> - 2016-10-24 14:02 -0700
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 14:42 -0700
                Re: pointers Tim Rentsch <txr@alumni.caltech.edu> - 2016-10-25 08:56 -0700
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 12:17 -0700
                Re: pointers Tim Rentsch <txr@alumni.caltech.edu> - 2016-10-26 06:37 -0700
              Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 08:49 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-24 17:25 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 09:52 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-24 18:15 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 12:20 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-24 20:58 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 13:16 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-24 23:53 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 13:38 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-25 23:06 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 15:39 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 00:26 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 16:44 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 01:02 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 17:35 -0700
                Re: pointers Ike Naar <ike@iceland.freeshell.org> - 2016-10-26 06:27 +0000
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 12:47 +0100
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-26 09:05 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 18:46 +0100
                Re: pointers supercat@casperkitty.com - 2016-10-26 11:44 -0700
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 20:12 +0100
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 20:30 +0100
                Re: pointers supercat@casperkitty.com - 2016-10-26 13:02 -0700
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-26 11:52 -0700
                Re: pointers Ike Naar <ike@iceland.freeshell.org> - 2016-10-26 19:11 +0000
                Re: pointers BartC <bc@freeuk.com> - 2016-10-26 21:25 +0100
                Re: pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2016-10-25 18:56 -0400
                Re: pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2016-10-25 19:12 -0400
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-25 16:31 -0700
                Re: pointers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-10-24 21:36 +0100
                Re: pointers BartC <bc@freeuk.com> - 2016-10-25 16:54 +0100
                Re: pointers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-10-25 19:09 +0100
                Re: pointers supercat@casperkitty.com - 2016-10-24 11:33 -0700
                Re: pointers Keith Thompson <kst-u@mib.org> - 2016-10-24 12:22 -0700
          Re: pointers James Kuyper <jameskuyper@verizon.net> - 2016-10-24 10:23 -0400
  Re: pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2016-10-23 12:31 -0400
    Re: pointers Richard Heathfield <rjh@cpax.org.uk> - 2016-10-23 17:38 +0100
  Re: pointers Lorinczy Zsigmond <zsiga@nospam.for.me> - 2016-10-24 14:02 +0200
  Re: pointers John Bode <jfbode1029@gmail.com> - 2016-10-24 13:34 -0700

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