add const
diff --git a/libasn1compiler/asn1c_C.c b/libasn1compiler/asn1c_C.c
index 7dc38cd..e5cd8dc 100644
--- a/libasn1compiler/asn1c_C.c
+++ b/libasn1compiler/asn1c_C.c
@@ -1674,7 +1674,7 @@
 			if((expr->expr_type == ASN_BASIC_ENUMERATED) ||
 				(expr->expr_type == ASN_BASIC_INTEGER)) {
 				if(expr->_type_referenced) {
-					OUT("extern asn_INTEGER_specifics_t "
+					OUT("extern const asn_INTEGER_specifics_t "
 						"asn_SPC_%s_specs_%d;\n", p, expr->_type_unique_index);
 				}
 			} else {