diff -r 818c4ac5d64d -r 13d0b67de111 stage4/generate_c/generate_c_il.cc
--- a/stage4/generate_c/generate_c_il.cc	Fri Dec 20 11:44:38 2013 +0000
+++ b/stage4/generate_c/generate_c_il.cc	Sun Dec 22 09:50:02 2013 +0000
@@ -367,7 +367,8 @@
       unsigned int vartype = search_var_instance_decl->get_vartype(symbol);
       if (wanted_variablegeneration == fparam_output_vg) {
         if (vartype == search_var_instance_decl_c::external_vt) {
-          if (search_var_instance_decl->type_is_fb(symbol))
+          if (!get_datatype_info_c::is_type_valid    (symbol->datatype)) ERROR;
+          if ( get_datatype_info_c::is_function_block(symbol->datatype))
             s4o.print(GET_EXTERNAL_FB_BY_REF);
           else
             s4o.print(GET_EXTERNAL_BY_REF);
@@ -379,7 +380,8 @@
       }
       else {
         if (vartype == search_var_instance_decl_c::external_vt) {
-          if (search_var_instance_decl->type_is_fb(symbol))
+          if (!get_datatype_info_c::is_type_valid    (symbol->datatype)) ERROR;
+          if ( get_datatype_info_c::is_function_block(symbol->datatype))
             s4o.print(GET_EXTERNAL_FB);
           else
             s4o.print(GET_EXTERNAL);
@@ -414,7 +416,8 @@
         unsigned int vartype = search_var_instance_decl->get_vartype(symbol);
         type_is_complex = analyse_variable_c::contains_complex_type(symbol);
         if (vartype == search_var_instance_decl_c::external_vt) {
-          if (search_var_instance_decl->type_is_fb(symbol))
+          if (!get_datatype_info_c::is_type_valid    (symbol->datatype)) ERROR;
+          if ( get_datatype_info_c::is_function_block(symbol->datatype))
             s4o.print(SET_EXTERNAL_FB);
           else
             s4o.print(SET_EXTERNAL);
@@ -572,7 +575,7 @@
 // SYM_REF2(structured_variable_c, record_variable, field_selector)
 void *visit(structured_variable_c *symbol) {
   TRACE("structured_variable_c");
-  bool type_is_complex = search_var_instance_decl->type_is_complex(symbol->record_variable);
+  bool type_is_complex = analyse_variable_c::is_complex_type(symbol->record_variable);
   switch (wanted_variablegeneration) {
     case complextype_base_vg:
     case complextype_base_assignment_vg: