diff --git a/occ/occlib/RuntimeControlledObject.h b/occ/occlib/RuntimeControlledObject.h
index c898667c..3002606d 100644
--- a/occ/occlib/RuntimeControlledObject.h
+++ b/occ/occlib/RuntimeControlledObject.h
@@ -26,6 +26,7 @@
 #ifndef OCC_RUNTIMECONTROLLEDOBJECT_H
 #define OCC_RUNTIMECONTROLLEDOBJECT_H
 
+#include <cstdint> 
 #include "OccState.h"
 #include "occ_export.h"