Re: Pre And Post Increment Operator Output

From	nick_keighley_nospam@hotmail.com
Newsgroups	comp.lang.c
Subject	Re: Pre And Post Increment Operator Output
Date	2012-06-25 00:27 -0700
Organization	http://groups.google.com
Message-ID	<aa9350d4-e997-4535-afbd-9ae0daa01811@googlegroups.com> (permalink)
References	(2 earlier) <js03uf$sb3$1@dont-email.me> <js092m$pov$1@dont-email.me> <lnipek8bri.fsf@nuthaus.mib.org> <js1gf5$l7v$1@dont-email.me> <0.06d3eacd14619c86d384.20120622143458BST.87ehp7o4fx.fsf@bsb.me.uk>

Show all headers | View raw

On Friday, June 22, 2012 2:34:58 PM UTC+1, Ben Bacarisse wrote:
> "BartC" <bc@freeuk.com> writes:

<snip>

> I've never liked the view that anything can happen with undefined code;
> it sounds too much like a cheap pedagogical trick to say that the above
> could format your drive. 

a poster on here used to claim he'd seen a system pop up the old DOS dialog box saying "Are You Sure You Want To Reformat C:?". For some sort of UB (not tricks with ++ but (I think) some sort of out of bounds thing).

> But the other extreme -- we all know what
> *should* happen, don't we? -- is equally unconvincing.  When the C
> language does not define the meaning of a bit of code, something else
> does, and that's enough for me.  I don't want to write code whose
> meaning is in the hands of unknown entities.  This point of view covers
> the much more significant case where I *know* what entity will define
> the meaning of otherwise undefined code -- POSIX, for example.

I've seen program behaviour change due to UB when a compiler was upgraded (same manufacturer). Changing optimisation can do it too.

<snip>

Thread

Pre And Post Increment Operator Output Yogesh Yadav Pacheria <yogeshpacheria@gmail.com> - 2012-06-21 12:56 -0700
  Re: Pre And Post Increment Operator Output Paul N <gw7rib@aol.com> - 2012-06-21 13:08 -0700
    Re: Pre And Post Increment Operator Output Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-21 16:52 -0400
  Re: Pre And Post Increment Operator Output John Gordon <gordon@panix.com> - 2012-06-21 20:11 +0000
  Re: Pre And Post Increment Operator Output Andrew Cooper <amc96@cam.ac.uk> - 2012-06-21 21:29 +0100
  Re: Pre And Post Increment Operator Output "BartC" <bc@freeuk.com> - 2012-06-21 22:08 +0100
    Re: Pre And Post Increment Operator Output Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-21 17:32 -0400
      Re: Pre And Post Increment Operator Output "BartC" <bc@freeuk.com> - 2012-06-22 00:00 +0100
        Re: Pre And Post Increment Operator Output Keith Thompson <kst-u@mib.org> - 2012-06-21 16:51 -0700
          Re: Pre And Post Increment Operator Output "BartC" <bc@freeuk.com> - 2012-06-22 11:09 +0100
            Re: Pre And Post Increment Operator Output nick_keighley_nospam@hotmail.com - 2012-06-22 05:36 -0700
            Re: Pre And Post Increment Operator Output Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-22 14:34 +0100
              Re: Pre And Post Increment Operator Output Les Cargill <lcargill99@comcast.com> - 2012-06-22 12:45 -0500
              Re: Pre And Post Increment Operator Output nick_keighley_nospam@hotmail.com - 2012-06-25 00:27 -0700
                Re: Pre And Post Increment Operator Output Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-25 14:32 +0100
                Re: Pre And Post Increment Operator Output Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-25 09:42 -0400
                Re: Pre And Post Increment Operator Output Kenneth Brody <kenbrody@spamcop.net> - 2012-06-25 11:33 -0400
              Re: Pre And Post Increment Operator Output Richard Damon <news.x.richarddamon@xoxy.net> - 2012-07-04 16:27 -0400
                Re: Pre And Post Increment Operator Output Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-07-04 17:46 -0400
                Re: Pre And Post Increment Operator Output Richard Damon <news.x.richarddamon@xoxy.net> - 2012-07-05 09:08 -0400
                Re: Pre And Post Increment Operator Output "io_x" <a@b.c.invalid> - 2012-07-06 17:34 +0200
            Re: Pre And Post Increment Operator Output Keith Thompson <kst-u@mib.org> - 2012-06-22 12:31 -0700
              Re: Pre And Post Increment Operator Output Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-22 16:21 -0400
        Re: Pre And Post Increment Operator Output Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-21 21:06 -0400
          Re: Pre And Post Increment Operator Output Noob <root@127.0.0.1> - 2012-06-22 13:30 +0200
            Re: BartC (was: Pre And Post Increment Operator Output) "BartC" <bc@freeuk.com> - 2012-06-22 13:06 +0100
            Re: Pre And Post Increment Operator Output Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-22 09:26 -0400
              Re: Pre And Post Increment Operator Output "Bartc" <bc@freeuk.com> - 2012-07-01 16:33 +0100
                Re: Pre And Post Increment Operator Output Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-01 17:15 +0100
                Re: Pre And Post Increment Operator Output "Bartc" <bc@freeuk.com> - 2012-07-01 18:45 +0100
                Re: Pre And Post Increment Operator Output Keith Thompson <kst-u@mib.org> - 2012-07-01 13:03 -0700
                Re: Pre And Post Increment Operator Output Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-02 00:18 +0100
        Re: Pre And Post Increment Operator Output Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-06-24 23:45 +0300
      Re: Pre And Post Increment Operator Output Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-24 09:15 -0700
        Re: Pre And Post Increment Operator Output Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-06-24 23:54 +0300
          Re: Pre And Post Increment Operator Output Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-24 15:12 -0700
            Re: Pre And Post Increment Operator Output "BartC" <bc@freeuk.com> - 2012-06-25 11:00 +0100
              Re: Pre And Post Increment Operator Output Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-25 13:53 -0700
  Re: Pre And Post Increment Operator Output Keith Thompson <kst-u@mib.org> - 2012-06-21 15:17 -0700
  Re: Pre And Post Increment Operator Output Yogesh Yadav Pacheria <yogeshpacheria@gmail.com> - 2012-06-21 21:03 -0700
    Re: Pre And Post Increment Operator Output nick_keighley_nospam@hotmail.com - 2012-06-22 00:06 -0700
    Re: Pre And Post Increment Operator Output Mark Bluemel <mark_bluemel@pobox.com> - 2012-06-22 08:30 +0100
    Re: Pre And Post Increment Operator Output John Bode <jfbode1029@gmail.com> - 2012-06-22 09:18 -0700
      Re: Pre And Post Increment Operator Output Keith Thompson <kst-u@mib.org> - 2012-06-22 12:36 -0700
      Re: Pre And Post Increment Operator Output lawrence.jones@siemens.com - 2012-06-22 14:25 -0400
  Re: Pre And Post Increment Operator Output "Heinrich Wolf" <invalid@invalid.invalid> - 2012-06-22 10:27 +0200
    Re: Pre And Post Increment Operator Output Kenneth Brody <kenbrody@spamcop.net> - 2012-06-22 13:46 -0400
      Re: Pre And Post Increment Operator Output Michael Press <rubrum@pacbell.net> - 2012-07-13 02:09 -0700
  Re: Pre And Post Increment Operator Output Ian Collins <ian-news@hotmail.com> - 2012-06-22 23:11 +1200
    Re: Pre And Post Increment Operator Output Mark Bluemel <mark_bluemel@pobox.com> - 2012-06-22 12:18 +0100

csiph-web