41 #ifndef PB_DS_RB_TREE_NODE_AND_IT_TRAITS_HPP 
   42 #define PB_DS_RB_TREE_NODE_AND_IT_TRAITS_HPP 
   52     template<
typename Key,
 
   55          template<
typename Node_CItr,
 
   68     typename types_traits<Key, Mapped, _Alloc, false>::value_type,
 
   69     typename tree_node_metadata_dispatch<Key, Mapped, Cmp_Fn, Node_Update,
 
   77     template<
typename Key,
 
   79          template<
typename Node_CItr,
 
   92       typename types_traits<Key, null_type, _Alloc, false>::value_type,
 
   93       typename tree_node_metadata_dispatch<Key, null_type, Cmp_Fn, Node_Update,
 
GNU extensions for policy-based data structures for public use. 
Represents no type, or absence of type, for template tricks. 
Tree traits class, primary template. 
Binary search tree traits, primary template.