|  | 
        A type trait that determines whether a require
        expression is well-formed.
      
template< typename T, typename... Properties> struct can_require : public integral_constant< bool, automatically_determined >
        Class template can_require
        is a trait that is derived from true_type
        if the expression asio::require(std::declval<T>(),
        std::declval<Properties>()...)
        is well formed; otherwise false_type.
      
        Header: asio/require.hpp
      
        Convenience header: asio.hpp