Re: [boost] [move][container] Review Request (new versions of Boost.Move and Boost.Container in sandbox and vault)

Subject: Re: [boost] [move][container] Review Request (new versions of Boost.Move and Boost.Container in sandbox and vault)
From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2009-08-12 15:53:53

David Abrahams escribió:

> Only in assignments?
> 
>   what about 
> 
>      consume(produce())
> 
>   scenarios?

obj produce()     { return obj(); }

void consume(obj ){}

int main()
{
    consume(produce());
    return 0;
}

At least in MSVC 7.1, GCC 4.3 and Intel 10.0 (which is EDG 3.8, 
http://software.intel.com/en-us/articles/intel-c-compiler-for-windows-general-compatibility-with-other-products/#17) 
this produces just a default constructor and no calls to copy 
constructor. And the same happens with:

    obj o = produce();
and
    obj o(produce());

>> This is not the case with constructors (the original Klaus Triendl proposal included
>> them, http://lists.boost.org/Archives/boost/2009/06/153266.php) because it terribly
>> uglifies syntax 
> 
> Are you sure you've looked at all the alternatives?  Every move library
> I'm aware of before yours supports implicitly move constructing from
> non-const rvalues.

Well, I can't say I've looked all of them ;-). I think this alternative 
is one of the most balanced ones, and allows writing optimal code for 
c++0x compilers without creating temporaries.

Regards,

Ion