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Re: I want to ask a question...

From James Kuyper <jameskuyper@verizon.net>
Newsgroups comp.lang.c
Subject Re: I want to ask a question...
Date 2015-08-20 13:02 -0400
Organization A noiseless patient Spider
Message-ID <mr514a$688$1@dont-email.me> (permalink)
References (3 earlier) <d9ea783a-d784-4e13-8133-3cb8d7b42032@googlegroups.com> <lnmvxm3gwa.fsf@kst-u.example.com> <mr38rc$mbb$1@speranza.aioe.org> <lnio8a3akw.fsf@kst-u.example.com> <mr5043$gfe$1@speranza.aioe.org>

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On 08/20/2015 12:43 PM, glen herrmannsfeldt wrote:
...
> For those using C as a replecement for assembly,

Which is an idiotic thing to do. If you want to specify precisely the
instructions to be generated, use a language whose defined behavior is
to do precisely that - C isn't such a language, and was never intended
to be.

> ... they often know
> exactly what the generated code will look like. ...

More accurately, they "assume they know".

> I am completely against programs that dereference pointers that
> aren't pointing to the right place, but not so much against ones
> that copy or compare pointers.

Why? It's undefined behavior either way, if the the pointer has an
indeterminate value, and the standard was written that way because there
are real systems on which comparison of a pointer with and indeterminate
value could have nasty consequences.
Copying with memcpy() should be safe even when the value of the pointer
is indeterminate, but it's hard to come up with a justification for
doing so, since it's just as much undefined behavior to do anything
meaningful with the copy as it was with the original.
-- 
James Kuyper

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Thread

Re: I want to ask a question... Gareth Owen <gwowen@gmail.com> - 2015-08-07 20:00 +0100
  Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-07 19:04 +0000
  Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-07 15:30 -0700
    Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-07 22:52 +0000
      Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-07 16:46 -0700
        Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-07 23:29 +0000
          Re: I want to ask a question... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-08-08 01:37 +0100
          Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-07 18:55 -0700
            Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-08 05:51 +0000
              Re: I want to ask a question... Robert Wessel <robertwessel2@yahoo.com> - 2015-08-08 01:44 -0500
    Re: I want to ask a question... Ken Brody <kenbrody@spamcop.net> - 2015-08-10 12:46 -0400
    Re: I want to ask a question... supercat@casperkitty.com - 2015-08-19 16:43 -0700
      Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-19 18:09 -0700
        Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-20 01:00 +0000
          Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-19 20:25 -0700
            Re: I want to ask a question... supercat@casperkitty.com - 2015-08-20 08:15 -0700
              Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-20 11:38 -0700
                Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-20 18:47 +0000
                Re: I want to ask a question... supercat@casperkitty.com - 2015-08-20 14:01 -0700
            Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-20 16:43 +0000
              Re: I want to ask a question... James Kuyper <jameskuyper@verizon.net> - 2015-08-20 13:02 -0400
                Re: I want to ask a question... Tonton Th <tTh@nowhere.invalid> - 2015-08-20 17:40 +0000
                Re: I want to ask a question... James Kuyper <jameskuyper@verizon.net> - 2015-08-20 15:27 -0400
                Re: I want to ask a question... David Brown <david.brown@hesbynett.no> - 2015-08-20 22:58 +0200
                Re: I want to ask a question... James Kuyper <jameskuyper@verizon.net> - 2015-08-20 23:24 -0400
                Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-21 06:19 +0000
                Re: I want to ask a question... Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-08-21 09:20 -0600
                Re: I want to ask a question... supercat@casperkitty.com - 2015-08-22 12:25 -0700
                Re: I want to ask a question... Robert Wessel <robertwessel2@yahoo.com> - 2015-08-23 01:33 -0500
                Re: I want to ask a question... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-08-20 19:28 +0000
              Re: I want to ask a question... Keith Thompson <kst-u@mib.org> - 2015-08-20 12:11 -0700
          Re: I want to ask a question... David Brown <david.brown@hesbynett.no> - 2015-08-20 10:02 +0200
        Re: I want to ask a question... raltbos@xs4all.nl (Richard Bos) - 2015-08-22 13:42 +0000
          Re: I want to ask a question... supercat@casperkitty.com - 2015-08-22 12:23 -0700

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