diff --git a/trick_source/codegen/Interface_Code_Gen/FieldDescription.cpp b/trick_source/codegen/Interface_Code_Gen/FieldDescription.cpp
index 8505c393..f1519ff2 100644
--- a/trick_source/codegen/Interface_Code_Gen/FieldDescription.cpp
+++ b/trick_source/codegen/Interface_Code_Gen/FieldDescription.cpp
@@ -57,6 +57,7 @@ FieldDescription::FieldDescription(
   is_stl(0) ,
   has_stl_clear(1) ,
   is_static(0) ,
+  is_reference(0) ,
   num_dims(0) ,
   array_sizes() {} ;
 
@@ -543,6 +544,14 @@ bool FieldDescription::isStatic() {
     return is_static ;
 }
 
+void FieldDescription::setReference(bool yes_no) {
+    is_reference = yes_no ;
+}
+
+bool FieldDescription::isReference() {
+    return is_reference ;
+}
+
 unsigned int FieldDescription::getNumDims() {
     return num_dims ;
 }
diff --git a/trick_source/codegen/Interface_Code_Gen/FieldDescription.hh b/trick_source/codegen/Interface_Code_Gen/FieldDescription.hh
index dff5fe86..28e2a745 100644
--- a/trick_source/codegen/Interface_Code_Gen/FieldDescription.hh
+++ b/trick_source/codegen/Interface_Code_Gen/FieldDescription.hh
@@ -87,6 +87,8 @@ class FieldDescription : public ConstructValues {
         bool hasSTLClear() ;
         void setStatic( bool yes_no ) ;
         bool isStatic() ;
+        void setReference( bool yes_no ) ;
+        bool isReference() ;
         void setInherited( bool yes_no ) ;
         bool isInherited() ;
         void setVirtualInherited( bool yes_no ) ;
@@ -184,6 +186,9 @@ class FieldDescription : public ConstructValues {
         /** is this field declared static */
         bool is_static ;
 
+        /** is this field a reference type */
+        bool is_reference ;
+
         /** map of strings to io numbers.  One copy for all fields */
         static std::map<std::string , unsigned int> io_map ;
 
diff --git a/trick_source/codegen/Interface_Code_Gen/FieldVisitor.cpp b/trick_source/codegen/Interface_Code_Gen/FieldVisitor.cpp
index 8c46bb1f..79bf2af8 100644
--- a/trick_source/codegen/Interface_Code_Gen/FieldVisitor.cpp
+++ b/trick_source/codegen/Interface_Code_Gen/FieldVisitor.cpp
@@ -43,12 +43,12 @@ bool FieldVisitor::VisitType(clang::Type *t) {
         std::cout << "FieldVisitor VisitType Type = " << t->getTypeClassName() << std::endl ;
         t->dump() ;
     }
-    // If this type is a reference, set IO to 0
     if ( t->isReferenceType() ) {
         if ( debug_level >= 3 ) {
-            std::cout << "FieldVisitor VisitType found reference, setIO = 0 " << std::endl ;
+            std::cout << "FieldVisitor VisitType found reference, setIO = 3 " << std::endl ;
         }
-        fdes->setIO(0) ;
+        fdes->setIO(3) ;
+        fdes->setReference(true) ;
     }
     return true;
 }
diff --git a/trick_source/codegen/Interface_Code_Gen/PrintFileContents10.cpp b/trick_source/codegen/Interface_Code_Gen/PrintFileContents10.cpp
index 4ba5d12a..533a16f7 100644
--- a/trick_source/codegen/Interface_Code_Gen/PrintFileContents10.cpp
+++ b/trick_source/codegen/Interface_Code_Gen/PrintFileContents10.cpp
@@ -76,7 +76,7 @@ void PrintFileContents10::print_field_attr(std::ostream & ostream ,  FieldDescri
         ostream << ", sizeof(" << fdes.getTypeName() << ")" ;
     }
     ostream << ", 0, 0, Language_CPP" ; // range_min, range_max, language
-    ostream << ", " << (fdes.isStatic() << 1) + (fdes.isDashDashUnits() << 2) << "," << std::endl ; // mods
+    ostream << ", " << fdes.isReference() + (fdes.isStatic() << 1) + (fdes.isDashDashUnits() << 2) << "," << std::endl ; // mods
     if ( fdes.isBitField() ) {
         // For bitfields we need the offset to start on 4 byte boundaries because that is what our
         // insert and extract bitfield routines work with.