Re: [Boost-users] boost::ptr_vector::sort with c++11 lambdas

Subject: Re: [Boost-users] boost::ptr_vector::sort with c++11 lambdas
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2011-11-12 08:47:32

Le 12/11/11 05:34, Michel Morin a écrit :
> Vicente J. Botet Escriba wrote:
>> is there any reason result_of couldn't use decltype when available? That is,
>> could Boost define  BOOST_RESULT_OF_USE_DECLTYPE when decltype is
>> supporeted?
> First, (almost) all current implementation of decltype does not support N3276.
> Non-N3276-decltype requires type-completeness, while traditional result_of
> does not. So result_of with non-N3276-decltype is incompatible with
> the traditional result_of.
>
> We should proceed gradually even if N3276-decltype is available, because
> * decltype-based result_of can break user codes with (unintended) use
>    of result_of.
> * Implementation of N3276-decltype might be buggy for some time.
>
> Daniel already made a first step by updating the documentation.
> The doc on trunk says:
>      In a future release, BOOST_RESULT_OF_USE_DECLTYPE may be enabled
>      by default on compilers that support decltype, so if you use the above
>      protocol please take care to ensure that the result_type and
>      result<>  members accurately represent the result type.
>      If you wish to continue to use the protocol on compilers that
>      support decltype, use boost::tr1_result_of, which is also defined
>      in<boost/utility/result_of.hpp>.
>
Thanks for the clarification. So if IUC, the use of 
BOOST_RESULT_OF_USE_DECLTYPE in the user code could break other parts of 
her application, isn't it?

Best,
Vicente