In how many ways should this fail?

Newsgroups	comp.lang.c
Subject	In how many ways should this fail?
From	Anders Wegge Keller <wegge@wegge.dk>
Date	2012-01-30 16:32 +0100
Message-ID	<87hazdcikg.fsf@huddi.jernurt.dk> (permalink)
Organization	SunSITE.dk - Supporting Open source

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 At work, we got into a talk about weird C constructs. One of my
collegues volunteered this line:

 (a>b)?a:b = 42;

 According to him, he have found three different compilers with three
different ways of handling this. One did nothing, one always assigned
to b, and the last one did what one should expect, were it legal.

 We ended up discussing what the acutal problem here is. The
diffrerent compilers we had at hand gave different diagnostics, so
they giv no clue. We narrowed it down to one of two:

1) a and b are not lvalues in this context.

2) This expression invokes undefined behaviour, since there are no
   sequence point between (a>b) and the assignment.

 

-- 
/Wegge

Leder efter redundant peering af dk.*,linux.debian.*

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In how many ways should this fail? Anders Wegge Keller <wegge@wegge.dk> - 2012-01-30 16:32 +0100
  Re: In how many ways should this fail? James Kuyper <jameskuyper@verizon.net> - 2012-01-30 11:07 -0500
    Re: In how many ways should this fail? James Kuyper <jameskuyper@verizon.net> - 2012-01-30 11:11 -0500
    Re: In how many ways should this fail? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-30 17:42 +0000
  Re: In how many ways should this fail? gwowen <gwowen@gmail.com> - 2012-01-30 08:16 -0800
    Re: In how many ways should this fail? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-30 17:35 +0000
      Re: In how many ways should this fail? gwowen <gwowen@gmail.com> - 2012-01-30 23:47 -0800
      Re: In how many ways should this fail? Tim Rentsch <txr@alumni.caltech.edu> - 2012-02-01 00:00 -0800
        Re: In how many ways should this fail? "BartC" <bc@freeuk.com> - 2012-02-01 12:14 +0000
          Re: In how many ways should this fail? James Kuyper <jameskuyper@verizon.net> - 2012-02-01 08:04 -0500
          Re: In how many ways should this fail? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-01 13:31 +0000
        Re: In how many ways should this fail? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-01 12:59 +0000
          Re: In how many ways should this fail? James Kuyper <jameskuyper@verizon.net> - 2012-02-01 08:37 -0500
            Re: In how many ways should this fail? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-01 16:40 +0000
              Re: In how many ways should this fail? James Kuyper <jameskuyper@verizon.net> - 2012-02-01 12:13 -0500
                Re: In how many ways should this fail? Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-08 12:49 -0800
    Re: In how many ways should this fail? Anders Wegge Keller <wegge@wegge.dk> - 2012-01-30 19:20 +0100
  Re: In how many ways should this fail? Devil with the China Blue Dress <chine.bleu@yahoo.com> - 2012-01-30 08:30 -0800
    Re: In how many ways should this fail? "BartC" <bc@freeuk.com> - 2012-01-30 16:43 +0000
      Re: In how many ways should this fail? Devil with the China Blue Dress <chine.bleu@yahoo.com> - 2012-01-30 09:17 -0800
      Re: In how many ways should this fail? Kaz Kylheku <kaz@kylheku.com> - 2012-01-30 17:31 +0000
      Re: In how many ways should this fail? James Kuyper <jameskuyper@verizon.net> - 2012-01-30 12:31 -0500
        Re: In how many ways should this fail? "BartC" <bc@freeuk.com> - 2012-01-30 18:16 +0000
          Re: In how many ways should this fail? James Kuyper <jameskuyper@verizon.net> - 2012-01-30 14:05 -0500
            Re: In how many ways should this fail? "BartC" <bc@freeuk.com> - 2012-01-30 19:30 +0000
              Re: In how many ways should this fail? Keith Thompson <kst-u@mib.org> - 2012-01-30 12:50 -0800
              Re: In how many ways should this fail? James Kuyper <jameskuyper@verizon.net> - 2012-01-30 16:17 -0500
              Re: In how many ways should this fail? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-30 21:48 +0000
                Re: In how many ways should this fail? "BartC" <bc@freeuk.com> - 2012-01-31 12:43 +0000
                Re: In how many ways should this fail? Zoltan Kocsi <zoltan@bendor.com.au> - 2012-02-01 00:46 +1100
                Re: In how many ways should this fail? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-31 13:57 +0000
                Re: In how many ways should this fail? "BartC" <bc@freeuk.com> - 2012-01-31 15:05 +0000
                Re: In how many ways should this fail? Devil with the China Blue Dress <chine.bleu@yahoo.com> - 2012-01-31 07:16 -0800
                Re: In how many ways should this fail? "BartC" <bc@freeuk.com> - 2012-01-31 17:37 +0000
                Re: In how many ways should this fail? James Kuyper <jameskuyper@verizon.net> - 2012-01-31 11:34 -0500
                Re: In how many ways should this fail? "BartC" <bc@freeuk.com> - 2012-01-31 17:39 +0000
                Re: In how many ways should this fail? Keith Thompson <kst-u@mib.org> - 2012-01-31 19:42 -0800
                Re: In how many ways should this fail? "BartC" <bc@freeuk.com> - 2012-02-01 11:57 +0000
                Re: In how many ways should this fail? James Kuyper <jameskuyper@verizon.net> - 2012-02-01 08:14 -0500
                Re: In how many ways should this fail? Philip Lantz <prl@canterey.us> - 2012-02-01 00:04 -0800
                Re: In how many ways should this fail? James Kuyper <jameskuyper@verizon.net> - 2012-01-31 09:05 -0500
                Re: In how many ways should this fail? Devil with the China Blue Dress <chine.bleu@yahoo.com> - 2012-01-31 06:45 -0800
                Re: In how many ways should this fail? "BartC" <bc@freeuk.com> - 2012-01-31 17:34 +0000
                Re: In how many ways should this fail? Keith Thompson <kst-u@mib.org> - 2012-01-31 19:26 -0800
                Re: In how many ways should this fail? Keith Thompson <kst-u@mib.org> - 2012-01-31 19:29 -0800
        Re: In how many ways should this fail? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-30 21:28 +0000
  Re: In how many ways should this fail? timprince <tprince@computer.org> - 2012-01-30 11:44 -0500
    Re: In how many ways should this fail? Kaz Kylheku <kaz@kylheku.com> - 2012-01-30 17:35 +0000
  Re: In how many ways should this fail? Kaz Kylheku <kaz@kylheku.com> - 2012-01-30 17:21 +0000
    Re: In how many ways should this fail? Anders Wegge Keller <wegge@wegge.dk> - 2012-01-30 19:22 +0100
      Re: In how many ways should this fail? 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-30 11:09 -0800
  Re: In how many ways should this fail? jacob navia <jacob@spamsink.net> - 2012-01-30 19:04 +0100
    Re: In how many ways should this fail? "BartC" <bc@freeuk.com> - 2012-01-30 18:21 +0000
      Re: In how many ways should this fail? Jens Gustedt <jens.gustedt@loria.fr> - 2012-01-30 20:15 +0100
        Re: In how many ways should this fail? "BartC" <bc@freeuk.com> - 2012-01-30 19:32 +0000
          Re: In how many ways should this fail? Jens Gustedt <jens.gustedt@loria.fr> - 2012-01-30 21:01 +0100
            Re: In how many ways should this fail? "BartC" <bc@freeuk.com> - 2012-01-30 20:22 +0000
              Re: In how many ways should this fail? Keith Thompson <kst-u@mib.org> - 2012-01-30 12:56 -0800
  Re: In how many ways should this fail? blp@cs.stanford.edu (Ben Pfaff) - 2012-01-30 10:07 -0800

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