41 #ifndef PB_DS_0_NODE_METADATA_HPP 
   42 #define PB_DS_0_NODE_METADATA_HPP 
   51     template<
typename Key, 
typename Data, 
typename _Alloc>
 
   56     typedef typename __traits_type::pointer         const_iterator;
 
   59     typedef const_iterator              value_type;
 
   60     typedef const_iterator              const_reference;
 
   61     typedef const_reference                 reference;
 
GNU extensions for policy-based data structures for public use. 
Traits for abstract types.