+/**
+ * Iterate the elements in the hash table.
+ *
+ * The typical usage is as below:
+ *
+ * // dump elements
+ * for (iter = ec_keyval_iter(keyval);
+ * ec_keyval_iter_valid(iter);
+ * ec_keyval_iter_next(iter)) {
+ * printf(" %s: %p\n",
+ * ec_keyval_iter_get_key(iter),
+ * ec_keyval_iter_get_val(iter));
+ * }
+ * ec_keyval_iter_free(iter);
+ *
+ * @param keyval
+ * The hash table.
+ * @return
+ * An iterator, or NULL on error (errno is set).
+ */
+struct ec_keyval_iter *
+ec_keyval_iter(const struct ec_keyval *keyval);
+
+/**
+ * Make the iterator point to the next element in the hash table.
+ *
+ * @param iter
+ * The hash table iterator.
+ */
+void ec_keyval_iter_next(struct ec_keyval_iter *iter);
+
+/**
+ * Free the iterator.
+ *
+ * @param iter
+ * The hash table iterator.
+ */
+void ec_keyval_iter_free(struct ec_keyval_iter *iter);
+
+/**
+ * Check if the iterator points to a valid element.
+ *
+ * @param iter
+ * The hash table iterator.
+ * @return
+ * true if the element is valid, else false.
+ */
+bool
+ec_keyval_iter_valid(const struct ec_keyval_iter *iter);
+
+/**
+ * Get the key of the current element.
+ *
+ * @param iter
+ * The hash table iterator.
+ * @return
+ * The current element key, or NULL if the iterator points to an
+ * invalid element.
+ */
+const char *
+ec_keyval_iter_get_key(const struct ec_keyval_iter *iter);
+
+/**
+ * Get the value of the current element.
+ *
+ * @param iter
+ * The hash table iterator.
+ * @return
+ * The current element value, or NULL if the iterator points to an
+ * invalid element.
+ */
+void *
+ec_keyval_iter_get_val(const struct ec_keyval_iter *iter);
+
+