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Re: C++ PATCH to add auto return type deduction with -std=c++1y


On Sun, 25 Mar 2012, Marc Glisse wrote:

- a first goal is simple functions, with a single return statement (which may even often be the only statement).

After playing with it a bit, I am not sure how to use it in the simple forwarding case:


T f(int);
auto g(int i){return f(i);}

If T is a reference, this does a copy.

auto&& g(int i){return f(i);}

Now if T is not a reference, this returns a reference to a destroyed temporary.

So I am back to writing the following, which is precisely what we never want to write:

auto g(int i)->decltype(f(i)){return f(i);}

Maybe having just auto (no auto const&, auto&& and others) without stripping cv-ref from it would work better in this case? It would have drawbacks in other cases...

I guess the discussion should happen on a different forum once the proposal is published...

--
Marc Glisse


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