Re: Life time of an object and Reference Var

From:
James Dennett <jdennett@cox.net>
Newsgroups:
comp.lang.c++.moderated
Date:
7 May 2006 08:39:34 -0400
Message-ID:
<3d97g.45116$iU2.32650@fed1read01>
maverick wrote:

Hi,

Pls consider the following code:

class Foo
{
};

Foo& getFoo ( void )
{
    Foo obj;


assuming you meant to add
       return obj; // NOTE: BUG
as the last line of this function.

}

int main ( void )


(Style note: most C++ "natives" don't use the C-style of
writing void to denote an empty argument list: int main()
means the same thing in C++. I have, however, seen house
styles which require the explicit "void" marker.)

{
    Foo &ref = g();
}

My question is if the obj will be live untill ref? because reference
variables must be initialised when declared and g() cannot return a
'dead' object. Is a logical bug as not to return reference of local
object or no problem at all.


Returning a reference to a local variable is a bug.
The object will be destroyed when the function exits
(or leaves the scope of that local variable), and
so you have a dangling reference.

-- James

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