Re: Returning a reference to a temporary object

From:

"Andrei Korostelev" <a.v.korostelev@tue.nl>

Newsgroups:

comp.lang.c++.moderated

Date:

31 May 2006 16:54:28 -0400

Message-ID:

<1149095839.776960.94580@c74g2000cwc.googlegroups.com>

Catalin Pitis wrote:

Hi *

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?

Thanks
Catalin

It's safe since value is actully copy-constructed there.

Another story would be if 'foo' were defined to return a reference:
std::string& foo()
{
  std::string str("something");
  return str;
}
Here str's destructor is called before the value is initialized, thus
you'd have problems here.

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