namespace boost {
  namespace icl {
    template<typename DomainT, 
             ICL_COMPARE Compare = ICL_COMPARE_INSTANCE(ICL_COMPARE_DEFAULT, DomainT)> 
      class closed_interval;
    template<typename DomainT, ICL_COMPARE Compare> 
      struct interval_traits<icl::closed_interval< DomainT, Compare >>;
    template<typename DomainT, ICL_COMPARE Compare> 
      struct interval_bound_type<closed_interval< DomainT, Compare >>;
    template<typename DomainT, ICL_COMPARE Compare> 
      struct type_to_string<icl::closed_interval< DomainT, Compare >>;
    template<typename DomainT> 
      struct value_size<icl::closed_interval< DomainT >>;
  }
}