Re: [boost] [operators] moving forward use return by reference for compilers with proper support?

Subject: Re: [boost] [operators] moving forward use return by reference for compilers with proper support?
From: Andrew Ho (helloworld922_at_[hidden])
Date: 2013-04-30 21:06:22

> They do NOT apply to this scenario:
>
> X&& func(X&& x) { return std::move(x); }
> const X& r3 = func(temporary()); // DANGLING REFERENCE
> X&& r4 = func(temporary()); // DANGLING REFERENCE

Hmm, I see.

sub-clause of 12.2 clause 5:

> The lifetime of a temporary bound to the returned value in a function
return statement (6.6.3) is not extended; the temporary is destroyed at the
end of the full-expression in the return statement.

I presume there must be some implementation detail on why a returned
temporaries' lifetime can't be extended.

Too bad, looks like return by value is the best option available.