diff --git a/Surface_mesher/demo/Surface_mesher/parameters.C b/Surface_mesher/demo/Surface_mesher/parameters.C
index e75323c042f..44a77f8a2da 100644
--- a/Surface_mesher/demo/Surface_mesher/parameters.C
+++ b/Surface_mesher/demo/Surface_mesher/parameters.C
@@ -10,6 +10,8 @@
 //
 // Author(s)     : Laurent Rineau
 
+#include <assert.h>
+
 #include "parameters.h"
 #include "implicit_functions.h"