diff --git a/src/face.hpp b/src/face.hpp
index 11800c8..18f40e6 100644
--- a/src/face.hpp
+++ b/src/face.hpp
@@ -376,7 +376,9 @@
    * If registeredPrefixId was obtained using setInterestFilter, the corresponding
    * InterestFilter will be unset too.
    *
-   * @param registeredPrefixId The ID returned from registerPrefix.
+   * @param registeredPrefixId The ID returned from registerPrefix
+   * @param onSuccess          Callback to be called when operation succeeds
+   * @param onFailure          Callback to be called when operation fails
    */
   void
   unregisterPrefix(const RegisteredPrefixId* registeredPrefixId,