diff --git a/root/io/uniquePointer/rwconst.C b/root/io/uniquePointer/rwconst.C
index b6a5dc5bc9..79d9c2d1c1 100644
--- a/root/io/uniquePointer/rwconst.C
+++ b/root/io/uniquePointer/rwconst.C
@@ -1,3 +1,5 @@
+#include "classes.h"
+
 #include "memory"
 #include "TFile.h"
 #include "TH1F.h"