diff --git a/types/user/enum/read.C b/types/user/enum/read.C
index 54f4050..541c321 100644
--- a/types/user/enum/read.C
+++ b/types/user/enum/read.C
@@ -4,6 +4,8 @@
 using ROOT::Experimental::REntry;
 using ROOT::Experimental::RNTupleReader;
 
+#include <TSystem.h>
+
 #include <cstdint>
 #include <fstream>
 #include <ostream>