Re: [boost] rvalue ref best practices?

Subject: Re: [boost] rvalue ref best practices?
From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2012-06-15 17:36:01

El 15/06/2012 19:41, Mathias Gaunard escribió:
> On 15/06/2012 18:02, Dave Abrahams wrote:
>
>> Most people don't know what "most objects" are like :-)
>
> The copy and swap idiom is usually what's used for non-containers.
>
>>
>>> It doesn't seem a good idea to introduce a new function overloading
>>> mechanism to drop that would always void this guarantee.
>>
>> I don't understand this sentence.
>
> Some words were left when I was rewriting it.
>
> It doesn't seem a good idea to introduce a new function overloading
> mechanism that would always void this guarantee.

I agree that is not desirable to weaken strong exception guarantees for 
objects because of the syntax. However there is an alternative syntax 
explained in:

http://article.gmane.org/gmane.comp.lib.boost.devel/231570

that does not void this guarantee as already constructed parameters are 
passed like references. I don't think this should surprise the programmer:

//A & B constructed, c & d reused
C c(...); D d(...);
[A a, B b] -> int ret = produce_abcd(a, b, c, d);

Best,

Ion