std::__detail::_Hashtable_traits< _Cache_hash_code, _Constant_iterators, _Unique_keys > Struct Template Reference
Containers » Unordered Associative » Base and Implementation Classes

## Public Types

using | __constant_iterators = __bool_constant< _Constant_iterators >
using | __hash_cached = __bool_constant< _Cache_hash_code >
using | __unique_keys = __bool_constant< _Unique_keys >

## Detailed Description

### template<bool _Cache_hash_code, bool _Constant_iterators, bool _Unique_keys>
struct std::__detail::_Hashtable_traits< _Cache_hash_code, _Constant_iterators, _Unique_keys >

struct _Hashtable_traits

Important traits for hash tables.

Template Parameters

  _Cache_hash_code | Boolean value. True if the value of the hash function is stored along with the value. This is a time-space tradeoff. Storing it may improve lookup speed by reducing the number of times we need to call the _Equal function.
  _Constant_iterators | Boolean value. True if iterator and const_iterator are both constant iterator types. This is true for unordered_set and unordered_multiset, false for unordered_map and unordered_multimap.
  _Unique_keys | Boolean value. True if the return value of _Hashtable::count(k) is always at most one, false if it may be an arbitrary number. This is true for unordered_set and unordered_map, false for unordered_multiset and unordered_multimap.

Definition at line 212 of file hashtable_policy.h.

The documentation for this struct was generated from the following file:

- hashtable_policy.h