diff --git a/vhdlpp/library.cc b/vhdlpp/library.cc
index 61ae426df..87cf41fa2 100644
--- a/vhdlpp/library.cc
+++ b/vhdlpp/library.cc
@@ -409,6 +409,14 @@ void generate_global_types(ActiveScope*res)
       res->use_name(perm_string::literal("natural"),   &primitive_NATURAL);
 }
 
+void emit_std_types(ostream&out)
+{
+    out << "`ifndef __VHDL_STD_TYPES" << endl;
+    out << "`define __VHDL_STD_TYPES" << endl;
+    out << "typedef enum bit { \\false , \\true } boolean ;" << endl;
+    out << "`endif" << endl;
+}
+
 bool is_global_type(perm_string name)
 {
       if (name == "boolean") return true;
diff --git a/vhdlpp/library.h b/vhdlpp/library.h
index ab6464f45..fe04aad23 100644
--- a/vhdlpp/library.h
+++ b/vhdlpp/library.h
@@ -26,6 +26,7 @@ extern void library_add_directory(const char*directory);
 
 extern Subprogram*library_find_subprogram(perm_string name);
 
+extern void emit_std_types(ostream&out);
 extern int emit_packages(void);
 
 #endif /* IVL_library_H */
diff --git a/vhdlpp/main.cc b/vhdlpp/main.cc
index b142d3845..418e73daa 100644
--- a/vhdlpp/main.cc
+++ b/vhdlpp/main.cc
@@ -232,6 +232,8 @@ int main(int argc, char*argv[])
 	    return 3;
       }
 
+      emit_std_types(cout);
+
       errors = emit_packages();
       if (errors > 0) {
 	    fprintf(stderr, "%d errors emitting packages.\n", errors);
diff --git a/vhdlpp/vtype_emit.cc b/vhdlpp/vtype_emit.cc
index 64577e004..bfce8e215 100644
--- a/vhdlpp/vtype_emit.cc
+++ b/vhdlpp/vtype_emit.cc
@@ -149,6 +149,8 @@ int VTypePrimitive::emit_primitive_type(ostream&out) const
       int errors = 0;
       switch (type_) {
 	  case BOOLEAN:
+	    out << "boolean";
+	    break;
 	  case BIT:
 	    out << "bool";
 	    break;