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Re: Equal yet different pointers

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NNTP-Posting-Date Thu, 16 Nov 2017 13:20:18 -0600
From Gareth Owen <gwowen@gmail.com>
Newsgroups comp.lang.c
Subject Re: Equal yet different pointers
References <pointers-20171116105459@ram.dialup.fu-berlin.de> <oujpb3$b9s$1@dont-email.me> <elePB.43928$WQ.6569@fx10.am4> <ouk4q6$ql4$1@dont-email.me> <87k1yqyxgx.fsf@kst-u.example.com>
Date Thu, 16 Nov 2017 19:20:18 +0000
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Keith Thompson <kst-u@mib.org> writes:

>> gcc /does/ do something wrong here - it accepts this program without
>> warnings, even with -Wall -Wextra.  So I do have something to complain
>> about here with gcc.
>
> Why do you expect a warning?  There may or may not be undefined
> behavior, but as far as I can tell no diagnostic is required.

Because some people have expectations that extend beyond the C standard?
I appreciate that the holy standard (peace be upon it) is your sole
point of reference in all things, but most people quite like that GCC
sometimes give diagnostics for dangerous or undefined constructs, even
when the standard says they're not required.

Its not unreasonable to expect one in a trivial case of UB like this.

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Re: Equal yet different pointers David Brown <david.brown@hesbynett.no> - 2017-11-16 11:29 +0100
  Re: Equal yet different pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-11-16 03:01 -0800
    Re: Equal yet different pointers "Bill Davy" <Bill@XchelSys.co.uk> - 2017-11-16 11:03 +0000
    Re: Equal yet different pointers David Brown <david.brown@hesbynett.no> - 2017-11-16 13:55 +0100
      Re: Equal yet different pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-11-16 06:44 -0800
        Re: Equal yet different pointers Spiros Bousbouras <spibou@gmail.com> - 2017-11-16 14:49 +0000
          Re: Equal yet different pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2017-11-16 08:28 -0800
        Re: Equal yet different pointers David Brown <david.brown@hesbynett.no> - 2017-11-16 16:46 +0100
      Re: Equal yet different pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2017-11-16 12:29 -0500
        Re: Equal yet different pointers Nick Bowler <nbowler@draconx.ca> - 2017-11-17 22:47 +0000
          Re: Equal yet different pointers Richard Damon <Richard@Damon-Family.org> - 2017-11-18 17:03 -0500
  Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-16 11:09 +0000
    Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-16 11:14 +0000
    Re: Equal yet different pointers "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-11-16 03:41 -0800
      Rick's neuroses (Was: Equal yet different pointers) gazelle@shell.xmission.com (Kenny McCormack) - 2017-11-16 12:11 +0000
        Re: Rick's neuroses (Was: Equal yet different pointers) "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-11-16 04:30 -0800
          Re: Rick's neuroses (Was: Equal yet different pointers) David Brown <david.brown@hesbynett.no> - 2017-11-16 14:52 +0100
            Obscure references (Was: Rick's neuroses (Was: Equal yet different pointers)) gazelle@shell.xmission.com (Kenny McCormack) - 2017-11-19 12:32 +0000
              Re: Obscure references Noob <root@127.0.0.1> - 2017-11-20 11:08 +0100
                Re: Obscure references David Brown <david.brown@hesbynett.no> - 2017-11-20 12:36 +0100
    Re: Equal yet different pointers David Brown <david.brown@hesbynett.no> - 2017-11-16 14:45 +0100
      Re: Equal yet different pointers Keith Thompson <kst-u@mib.org> - 2017-11-16 08:55 -0800
        Re: Equal yet different pointers Spiros Bousbouras <spibou@gmail.com> - 2017-11-16 17:09 +0000
          Re: Equal yet different pointers Keith Thompson <kst-u@mib.org> - 2017-11-16 09:33 -0800
        Re: Equal yet different pointers Gareth Owen <gwowen@gmail.com> - 2017-11-16 19:20 +0000
          Re: Equal yet different pointers Keith Thompson <kst-u@mib.org> - 2017-11-16 11:36 -0800
            Re: Equal yet different pointers David Brown <david.brown@hesbynett.no> - 2017-11-16 22:50 +0100
              Re: Equal yet different pointers supercat@casperkitty.com - 2017-11-16 14:34 -0800
                Re: Equal yet different pointers David Brown <david.brown@hesbynett.no> - 2017-11-17 10:44 +0100
                Re: Equal yet different pointers supercat@casperkitty.com - 2017-11-17 08:23 -0800
                Re: Equal yet different pointers David Brown <david.brown@hesbynett.no> - 2017-11-17 19:13 +0100
                Re: Equal yet different pointers supercat@casperkitty.com - 2017-11-17 16:45 -0800
                Re: Equal yet different pointers Spiros Bousbouras <spibou@gmail.com> - 2017-11-18 07:30 +0000
        Re: Equal yet different pointers David Brown <david.brown@hesbynett.no> - 2017-11-16 22:25 +0100
          Re: Equal yet different pointers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-11-16 23:11 +0000
            Re: Equal yet different pointers supercat@casperkitty.com - 2017-11-16 15:47 -0800
            Re: Equal yet different pointers David Brown <david.brown@hesbynett.no> - 2017-11-17 10:49 +0100
      Re: Equal yet different pointers Gareth Owen <gwowen@gmail.com> - 2017-11-16 19:20 +0000
        Re: Equal yet different pointers "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-11-16 11:26 -0800
        Re: Equal yet different pointers gazelle@shell.xmission.com (Kenny McCormack) - 2017-11-16 22:22 +0000
          Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-16 23:09 +0000
            Re: Equal yet different pointers gazelle@shell.xmission.com (Kenny McCormack) - 2017-11-17 08:50 +0000
              Re: Equal yet different pointers Gareth Owen <gwowen@gmail.com> - 2017-11-17 17:42 +0000
                Re: Equal yet different pointers gazelle@shell.xmission.com (Kenny McCormack) - 2017-11-17 19:35 +0000
      Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-16 23:34 +0000
        Re: Equal yet different pointers supercat@casperkitty.com - 2017-11-16 15:58 -0800
        Re: Equal yet different pointers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-11-17 00:57 +0000
        Re: Equal yet different pointers David Brown <david.brown@hesbynett.no> - 2017-11-17 12:32 +0100
          Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-17 12:31 +0000
            Re: Equal yet different pointers mark.bluemel@gmail.com - 2017-11-17 07:23 -0800
            Re: Equal yet different pointers David Brown <david.brown@hesbynett.no> - 2017-11-17 17:14 +0100
              Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-18 00:12 +0000
                Re: Equal yet different pointers Ian Collins <ian-news@hotmail.com> - 2017-11-18 13:39 +1300
                Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-18 01:39 +0000
                Re: Equal yet different pointers Ian Collins <ian-news@hotmail.com> - 2017-11-18 14:42 +1300
                Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-18 02:01 +0000
                Re: Equal yet different pointers Melzzzzz <Melzzzzz@zzzzz.com> - 2017-11-18 02:07 +0000
                Re: Equal yet different pointers Ian Collins <ian-news@hotmail.com> - 2017-11-18 15:35 +1300
                Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-18 11:23 +0000
                Re: Equal yet different pointers Ian Collins <ian-news@hotmail.com> - 2017-11-19 12:02 +1300
                Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-18 23:25 +0000
                Re: Equal yet different pointers Ian Collins <ian-news@hotmail.com> - 2017-11-19 13:44 +1300
                Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-19 01:05 +0000
                Re: Equal yet different pointers Ian Collins <ian-news@hotmail.com> - 2017-11-19 14:30 +1300
                Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-19 01:48 +0000
                Re: Equal yet different pointers Ian Collins <ian-news@hotmail.com> - 2017-11-19 16:21 +1300
                Re: Equal yet different pointers Reinhardt Behm <rbehm@hushmail.com> - 2017-11-19 11:44 +0800
                Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-19 10:10 +0000
                Re: Equal yet different pointers mark.bluemel@gmail.com - 2017-11-20 00:52 -0800
                Re: Equal yet different pointers David Brown <david.brown@hesbynett.no> - 2017-11-19 23:27 +0100
                Re: Equal yet different pointers Richard Damon <Richard@Damon-Family.org> - 2017-11-19 22:48 -0500
                Re: Equal yet different pointers Ian Collins <ian-news@hotmail.com> - 2017-11-20 16:52 +1300
    Re: Equal yet different pointers Spiros Bousbouras <spibou@gmail.com> - 2017-11-16 14:28 +0000
      Re: Equal yet different pointers Barry Schwarz <schwarzb@dqel.com> - 2017-11-16 07:10 -0800
        Re: Equal yet different pointers David Brown <david.brown@hesbynett.no> - 2017-11-16 16:51 +0100
          Re: Equal yet different pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2017-11-16 12:57 -0500
      Re: Equal yet different pointers supercat@casperkitty.com - 2017-11-16 08:03 -0800
      Re: Equal yet different pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2017-11-16 12:38 -0500
        Re: Equal yet different pointers "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-11-16 20:13 +0100
          Re: Equal yet different pointers "James R. Kuyper" <jameskuyper@verizon.net> - 2017-11-16 14:29 -0500
    Re: Equal yet different pointers Jorgen Grahn <grahn+nntp@snipabacken.se> - 2017-11-16 15:57 +0000
      Re: Equal yet different pointers Spiros Bousbouras <spibou@gmail.com> - 2017-11-16 16:07 +0000
        Re: Equal yet different pointers Jorgen Grahn <grahn+nntp@snipabacken.se> - 2017-11-16 19:01 +0000
          Re: Equal yet different pointers Spiros Bousbouras <spibou@gmail.com> - 2017-11-16 19:14 +0000
            Re: Equal yet different pointers Jorgen Grahn <grahn+nntp@snipabacken.se> - 2017-11-16 19:47 +0000
      Re: Equal yet different pointers bartc <bc@freeuk.com> - 2017-11-16 23:08 +0000
        Re: Equal yet different pointers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-11-17 00:33 +0000

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