# Hash and Probe Policies

As mentioned in Hash Policies, some of the containers require a ranged-hash function policy for mapping key types into a non-negative integral type in a range. E.g., collision-based containers (`cc_ht_map`, `cc_ht_set`, `cc_ht_multimap`, and `cc_ht_multiset`), require a ranged-hash function.

Similarly, some hash tables need a ranged-probe function policy for mapping key types into a sequence of non-negative integral types in a range. E.g., probing-based containers (`gp_ht_map`, `gp_ht_set`, `gp_ht_multimap`, and `gp_ht_multiset`), require a ranged-hash function.

Policy Classes contains classes for creating ranged-hash and ranged-probe function policies.