On 1 Feb 2017 7:51 p.m., "Olaf van der Spek" wrote: On Wed, Feb 1, 2017 at 12:39 PM, Oswin Krause wrote:

On 2017-02-01 12:02, Olaf van der Spek wrote:

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On Wed, Feb 1, 2017 at 11:24 AM, Oswin Krause wrote:

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For me, the biggest problem of the proposal is that observer_ptr<T> is implicitely constructed from T&. In my code I often use:

Foo a; Bar b(&a);//&a signals that b only references to a, but does not copy

it.

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Now, when I write

Bar b(a); //so is a now copied?

While the interface is clearer in documentation, the usage is less

clear!

IMO using pointers instead of references to indicate something isn't copied is bad practice.. the language is C++, not C.

This is not a C vs C++ thing.

But assume it was. How would you indicate that in C++? It should be clear without looking at the reference whether it is okay for a to go out of scope before b or not.

There's no way to indicate that, AFAIK. The way to indicate it is to require explicit conversion from `T&` to your pointer-like type. `make_observer` can play the role of a type-safe `&`. I would be happy to remove implicit conversion from `T&` if it is agreed to be undesirable. Joseph