Re: Returning a reference to a temporary object

From:

"Victor Bazarov" <v.Abazarov@comAcast.net>

Newsgroups:

comp.lang.c++.moderated

Date:

31 May 2006 16:58:52 -0400

Message-ID:

<e5kqdn$eb8$1@news.datemas.de>

Catalin Pitis wrote:

I have a piece of code looking like this:

#include <iostream>
#include <string>

using namespace std;

string foo()
{
   return "Something";
}

int main( int, char*[])
{
   const std::string& value = foo(); // This is the interest point
   /// do something here....
   return 0;
}

I've tested the code with MS VC 8.0 and it seems that allows me to
hold a const reference to a temporary object without crashing (both
debug and release targets).

However, is this allowed, according to the standard? Can I use it like
this?

Yes, it is allowed. Yes, you can. You should know, however, that with
return value optimization (RVO) the compiler can forgo creation of extra
temporary objects if you write

     std::string value = foo(); // not a reference

the benefit here is that 'value' can be reused.
V
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