diff --git a/tools/nfdc/find-face.hpp b/tools/nfdc/find-face.hpp
index 2661aa6..120718b 100644
--- a/tools/nfdc/find-face.hpp
+++ b/tools/nfdc/find-face.hpp
@@ -92,6 +92,11 @@
     return m_results;
   }
 
+  /** \return FaceId for all results
+   */
+  std::set<uint64_t>
+  getFaceIds() const;
+
   /** \return a single face status
    *  \pre getResults().size() == 1
    */