Re: [boost] [move] new rvalue reference emulation

Subject: Re: [boost] [move] new rvalue reference emulation
From: Vicente Botet (vicente.botet_at_[hidden])
Date: 2012-01-21 19:22:44

Jeffrey Lee Hellrung, Jr.-2 wrote
> 
> 2011/4/11 Ion Gaztañaga <igaztanaga@>
> 
>> El 11/04/2011 3:22, Jeffrey Lee Hellrung, Jr. escribió:
>>
>>> On Mon, Apr 4, 2011 at 10:36 AM, Jeffrey Lee Hellrung, Jr.<
>>> jeffrey.hellrung@>  wrote:
>>> [...snipping original description...]
>>>
>>
>> Sorry for the lack of feedaback! I tried to your example in some
>> compilers
>> and checked that MSVC7.1 does not like pointer to function storage in the
>> generic rv (it's a msvc bug, but annoying, nevertheless).
> 
> 
> It sounds like that could be easily worked around without too much
> obfuscation.
> 
> 
>> I've been very busy with several interprocess issues and I couldn't take
>> time to study this but I promise to dedicate some time soon.
> 
> 
> Great, thanks; as long as I know that you've seen the message, I'm happy
> :)
> 
> 
>> I was a bit confused as you use a function object in your example. Can't
>> we
>> take rid of that function object and apply it to free functions?
> 
> 
> You can, but you would still need a function object to execute the visitor
> pattern on the genrv object, since the visitor must be polymorphic (it
> must
> accept many different argument types).  Making the function object *both*
> the visitor *and* the "housing" of the overload set is merely a
> convenience.
> 
> 
>> How can we apply this to the constructor of an object?
>>
> 
> Unfortunately, here the technique can get quite cumbersome.  After
> thinking
> a little about this, I think you'd have to be in one of the following
> situations:
> - Use no initializer lists, and perform the construction in an "init"
> method.  This should be okay for, e.g., pimpl classes.
> - All member object(s) and base class(es) that receive the to-be-forwarded
> argument can accept a genrv object.
> - Use some kind of "typeless opaque storage" for all member object(s) that
> receive the to-be-forwarded argument to delay initialization until the
> constructor body.  Should be strongly discouraged, but sometimes you gotta
> do what you gotta do...
> 
> 

Hi,

Are there any news about this Move improvements?

Best,
Vicente

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