diff --git a/skeletons/OBJECT_IDENTIFIER.c b/skeletons/OBJECT_IDENTIFIER.c
index 798929f..f899ab0 100644
--- a/skeletons/OBJECT_IDENTIFIER.c
+++ b/skeletons/OBJECT_IDENTIFIER.c
@@ -310,7 +310,7 @@
 asn_dec_rval_t
 OBJECT_IDENTIFIER_decode_xer(asn_codec_ctx_t *opt_codec_ctx,
 	asn_TYPE_descriptor_t *td, void **sptr, const char *opt_mname,
-		void *buf_ptr, size_t size) {
+		const void *buf_ptr, size_t size) {
 
 	return xer_decode_primitive(opt_codec_ctx, td,
 		sptr, sizeof(OBJECT_IDENTIFIER_t), opt_mname,