• _config : pmem::kv::config
• _db : pmem::kv::db
• c_cmp : pmem::kv::internal::comparator_config_entry
• cmp : pmem::kv::internal::comparator_wrapper< Comparator >
• ptr : pmem::kv::internal::comparator_config_entry , pmem::kv::internal::unique_ptr_wrapper< T, D >