+typedef struct hash_tuning Hash_tuning;
+
+struct hash_table;
+
+typedef struct hash_table Hash_table;
+
+/* Information and lookup. */
+size_t hash_get_n_buckets (const Hash_table *) _GL_ATTRIBUTE_PURE;
+size_t hash_get_n_buckets_used (const Hash_table *) _GL_ATTRIBUTE_PURE;
+size_t hash_get_n_entries (const Hash_table *) _GL_ATTRIBUTE_PURE;
+size_t hash_get_max_bucket_length (const Hash_table *) _GL_ATTRIBUTE_PURE;
+bool hash_table_ok (const Hash_table *) _GL_ATTRIBUTE_PURE;
+void hash_print_statistics (const Hash_table *, FILE *);
+void *hash_lookup (const Hash_table *, const void *);
+
+/* Walking. */
+void *hash_get_first (const Hash_table *) _GL_ATTRIBUTE_PURE;
+void *hash_get_next (const Hash_table *, const void *);
+size_t hash_get_entries (const Hash_table *, void **, size_t);
+size_t hash_do_for_each (const Hash_table *, Hash_processor, void *);
+
+/* Allocation and clean-up. */
+size_t hash_string (const char *, size_t) _GL_ATTRIBUTE_PURE;
+void hash_reset_tuning (Hash_tuning *);
+Hash_table *hash_initialize (size_t, const Hash_tuning *,
+ Hash_hasher, Hash_comparator,
+ Hash_data_freer) _GL_ATTRIBUTE_WUR;
+void hash_clear (Hash_table *);
+void hash_free (Hash_table *);
+
+/* Insertion and deletion. */
+bool hash_rehash (Hash_table *, size_t) _GL_ATTRIBUTE_WUR;
+void *hash_insert (Hash_table *, const void *) _GL_ATTRIBUTE_WUR;
+
+/* Deprecate this interface. It has been renamed to hash_insert_if_absent. */
+int hash_insert0 (Hash_table *table, /* FIXME: remove in 2013 */
+ const void *entry,
+ const void **matched_ent) _GL_ATTRIBUTE_DEPRECATED;
+int hash_insert_if_absent (Hash_table *table, const void *entry,
+ const void **matched_ent);
+void *hash_delete (Hash_table *, const void *);
+
+#endif