The type for atomic-write backend stores.

The type for keys.

The type for raw values.

mem t k is true iff k is present in t.

find t k is Some v if k is associated to v in t and None is k is not present in t.

set t k v replaces the contents of k by v in t. If k is not already defined in t, create a fresh binding. Raise Invalid_argument if k is the empty path.

test_and_set t key ~test ~set sets key to set only if the current value of key is test and in that case returns true. If the current value of key is different, it returns false. None means that the value does not have to exist or is removed.

Note: The operation is guaranteed to be atomic.

remove t k remove the key k in t.

list t it the list of keys in t.

The type of watch handlers.

watch t ?init f adds f to the list of t's watch handlers and returns the watch handler to be used with unwatch. init is the optional initial values. It is more efficient to use watch_key to watch only a single given key.

watch_key t k ?init f adds f to the list of t's watch handlers for the key k and returns the watch handler to be used with unwatch. init is the optional initial value of the key.

unwatch t w removes w from t's watch handlers.

Clear the store. This operation is expected to be slow.

close t frees up all the resources associated with t. Any operations run on a closed handle will raise Closed.