Guarantee of side-effect free assignment

From:
"Alf P. Steinbach" <alfps@start.no>
Newsgroups:
comp.std.c++
Date:
Sat, 6 Oct 2007 19:07:24 CST
Message-ID:
<13gg864lbre40bd@corp.supernews.com>
 From discussions in [comp.lang.c++] and [comp.lang.c++.moderated], as
well as articles on the net about concurrency in C++, I'm reasonably
sure that given

   #include <iostream>
   #include <ostream>

   struct S { S(){ throw 123; } int foo(){ return 666; } };

   int main()
   {
       S* p = 0;

       try
       {
           p = new S();
       }
       catch( ... )
       {}

       if( p ) { std::cout << p->foo() << std::endl; }
   }

there is no guarantee that this code will not end up in a call to
p->foo() with an invalid pointer p, i.e., that might well happen.

Surely that couldn't have been the committee's intention?

Why isn't assignment treated as a function call?

Cheers,

- Alf

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

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