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Re: Pointers and Sequence Point

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On 5/2/2011 7:38 AM, arnuld wrote:
> I have this program which is causing confusion to me. I am told that last
> printf() of main() will always print "Second", not "First". I think line:
>
>   x = myAlloc(x);

While it is possible to write evil code in which myAlloc could modify x, 
in C myAlloc receives a copy of the value of x and has no clue where x 
is or how to modify it.  There are not two or more instances of 
modifying x between sequence points.

> is UB. My colleague is disagreeing on this while I was saying that its UB
> because there is no sequence point here. It is just like using this line:
>
>   i = i++;

Now there _are_ two instances of modifying i between sequence points.

Do you see the difference?

> But he says that sequence point will not affect the pointers

"pointers" are not relevant.

> and hence
> this is perfectly valid ANSI C program. I am confused on this:

Your program has other problems, but none related to the question you 
raised.

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Pointers and Sequence Point arnuld <sunrise@invalid.address> - 2011-05-02 11:38 +0000
  Re: Pointers and Sequence Point James Kuyper <jameskuyper@verizon.net> - 2011-05-02 08:23 -0400
  Re: Pointers and Sequence Point Martin Ambuhl <mambuhl@earthlink.net> - 2011-05-02 09:58 -0400
    Re: Pointers and Sequence Point Chad <cdalten@gmail.com> - 2011-05-02 09:36 -0700
      Re: Pointers and Sequence Point Angel <angel+news@spamcop.net> - 2011-05-02 17:21 +0000
      Re: Pointers and Sequence Point James Kuyper <jameskuyper@verizon.net> - 2011-05-02 23:20 -0400
        Re: Pointers and Sequence Point Keith Thompson <kst-u@mib.org> - 2011-05-02 23:26 -0700
          Re: Pointers and Sequence Point James Kuyper <jameskuyper@verizon.net> - 2011-05-03 05:33 -0400
    Re: Pointers and Sequence Point Kenneth Brody <kenbrody@spamcop.net> - 2011-05-02 13:35 -0400
      Re: Pointers and Sequence Point Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2011-05-03 17:45 +0300
  Re: Pointers and Sequence Point John Bode <jfbode1029@gmail.com> - 2011-05-02 10:17 -0700
  Re: Pointers and Sequence Point Tim Rentsch <txr@alumni.caltech.edu> - 2011-05-02 10:31 -0700
  Re: Pointers and Sequence Point "Morris Keesan" <mkeesan@post.harvard.edu> - 2011-05-02 20:55 -0400
    Re: Pointers and Sequence Point David Resnick <lndresnick@gmail.com> - 2011-05-03 08:01 -0700

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