- * @return NULL if seen_results_count is 0, otherwise a BF
- * that would match the given results.
+ * @return #GNUNET_SYSERR if not supported, #GNUNET_OK on success
+ */
+int
+GNUNET_BLOCK_group_set_seen (struct GNUNET_BLOCK_Group *bg,
+ const struct GNUNET_HashCode *seen_results,
+ unsigned int seen_results_count);
+
+
+/**
+ * Try merging two block groups. Afterwards, @a bg1 should remain
+ * valid and contain the rules from both @a bg1 and @bg2, and
+ * @a bg2 should be destroyed (as part of this call). The latter
+ * should happen even if merging is not supported.
+ *
+ * @param[in,out] bg1 first group to merge, is updated
+ * @param bg2 second group to merge, is destroyed
+ * @return #GNUNET_OK on success,
+ * #GNUNET_NO if merge failed due to different nonce
+ * #GNUNET_SYSERR if merging is not supported