Re: Returning Refs

From:
"Victor Bazarov" <v.Abazarov@comAcast.net>
Newsgroups:
comp.lang.c++
Date:
Mon, 2 Apr 2007 10:32:07 -0400
Message-ID:
<eur459$dpi$1@news.datemas.de>
Greg Herlihy wrote:

On Apr 1, 6:18 pm, "Jim Langston" <tazmas...@rocketmail.com> wrote:

"Victor Bazarov" <v.Abaza...@comAcast.net> wrote in message

news:yvqdnS_pT4j-WJLbnZ2dnUVZ_v6tnZ2d@comcast.com...

Jim Langston wrote:

<EvilOld...@googlemail.com> wrote in message
news:1175349463.536538.36070@y80g2000hsf.googlegroups.com...

const Thing &operator++(int)
{
Thing temp = *this;
operator++();
return temp;
}
Is this code robust ?


No. You are returning a reference to a temporary item.


Just a clarification here... 'Temporary' has a very specific
meaning in C++. 'temp' here is an *automatic* object, and not
a C++ temporary. While it *is* temporary (hell, the whole
program is temporary since it only lasts while in computer's
memory), it has different lifetime than a _true temporary_.


Since a temporary is always used (though it may be optimized away) to
return a result from a function call, [..]


Uh... Wrong.

    int& foo() {
        static int blah = 42;
        return blah;
    }

*What* temporary?

V
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