Re: Missed optimization with const member

[Ion Gaztañaga <igaztanaga at gmail dot com>]

On 05/07/2017 17:24, Martin Sebor wrote:

> [*] While the example (copied below) is valid, accessing the object
> after someFunction() has returned via a reference or pointer to it
> is not.
>
>    void somefunction(const Object& object);
>    {
>      void* p = &object;
>      object.~Object();
>      new(p) Object();
>    }

I think it's problematic as explained in p0532r0.pdf. We construct and 
destroy objects in the internal buffer of std::vector and we don't 
update the pointer every time. I don't see myself understanding when 
std::launder must be used, looks too expert-grade feature.

Best,

Ion