diff --git a/cg/cglib01.cpp b/cg/cglib01.cpp
index 5189c8e14..de638a4f5 100755
--- a/cg/cglib01.cpp
+++ b/cg/cglib01.cpp
@@ -3,6 +3,7 @@
 #include <diction.h>
 #include <mask.h>
 #include <recarray.h>
+#include <relation.h>
 #include <tabutil.h>
 
 #include <pconti.h>