`cmpfn` stores the comparison function specified in `hashmap_init()`. In
advanced scenarios, it may be useful to change this, e.g. to switch between
case-sensitive and case-insensitive lookup.
++
+When `disallow_rehash` is set, automatic rehashes are prevented during inserts
+and deletes.
`struct hashmap_entry`::
`unsigned int strihash(const char *buf)`::
`unsigned int memhash(const void *buf, size_t len)`::
`unsigned int memihash(const void *buf, size_t len)`::
+`unsigned int memihash_cont(unsigned int hash_seed, const void *buf, size_t len)`::
Ready-to-use hash functions for strings, using the FNV-1 algorithm (see
http://www.isthe.com/chongo/tech/comp/fnv).
`memihash` operate on arbitrary-length memory.
+
`strihash` and `memihash` are case insensitive versions.
++
+`memihash_cont` is a variant of `memihash` that allows a computation to be
+continued with another chunk of data.
`unsigned int sha1hash(const unsigned char *sha1)`::
+
Returns the removed entry, or NULL if not found.
+`void hashmap_disallow_rehash(struct hashmap *map, unsigned value)`::
+
+ Disallow/allow automatic rehashing of the hashmap during inserts
+ and deletes.
++
+This is useful if the caller knows that the hashmap will be accessed
+by multiple threads.
++
+The caller is still responsible for any necessary locking; this simply
+prevents unexpected rehashing. The caller is also responsible for properly
+sizing the initial hashmap to ensure good performance.
++
+A call to allow rehashing does not force a rehash; that might happen
+with the next insert or delete.
+
`void hashmap_iter_init(struct hashmap *map, struct hashmap_iter *iter)`::
`void *hashmap_iter_next(struct hashmap_iter *iter)`::
`void *hashmap_iter_first(struct hashmap *map, struct hashmap_iter *iter)`::