Re: [Boost-users] [result_of]

26 Oct 2009


      er wrote:
...
If G derives privately from F,
and F::result_type is defined,
but I provide, say, G::result,
boost::result_of::type attempts to access the private 
F::result_type, instead of G::result::type.
I guess, if I really want to keep F a private base, I could wrap it in a 
class, W<F>, that does not expose result_type, yet I'm hoping someone 
might have a better idea.
The only solution I can think of is to (partially) specialize 
boost::result_of directly, as below ...

   #include 

   struct B
   {
     typedef void result_type;
   };

   struct D : private B
   {
     template<class S>
     struct result
     {
       typedef int type;
     };
   };

   namespace boost
   {
     template<typename T>
     struct result_of : D::result {};

     template<typename T>
     struct result_of : D::result {};

     // For completeness, specialize for D volatile and
     // D const volatile, too.
   }

   int main()
   {
     typedef boost::result_of::type t;
   }

HTH,

-- 
Eric Niebler
BoostPro Computing
http://www.boostpro.com