C ++ Boost binding value type

I'm looking at the documentation and source code, but I can't figure out how to get the return type of the boost bind function. I am trying to accomplish the following:

 35 template<typename T,size_t N, class F>
 36 boost::array<typename F::value_type, N> make_array(T (&input)[N], F unary) {
 37     boost::array<typename F::value_type, N> array;
 38     std::transform(input, input + N, array.begin(), unary);
 39     return array;
 40 }

      

        
        
        
      

    

where F can be a connecting functor. the above doesn't work because the functor has no value_type. in this regard, there is a standard interface for a unary / binary functor with respect to the return value.

: it should be result_type

. also the equivalent is defined argument_type

and first/second_argument_type

for binary functions

thanks