diff --git a/src/processor_loopclosure_base.h b/src/processor_loopclosure_base.h
index f925669194a02fae352caa70035084567024ebdf..3b7e24fafe4320610f0d11de804db24f2f35cd8d 100644
--- a/src/processor_loopclosure_base.h
+++ b/src/processor_loopclosure_base.h
@@ -115,7 +115,7 @@ protected:
    *
    * WARNING! This function only votes! It does not create KeyFrames!
    */
-  virtual bool voteForKeyFrame() = 0;
+  virtual bool voteForKeyFrame() override = 0;
 };
 
 inline const std::vector<FrameBasePtr>&