add const
diff --git a/skeletons/ber_decoder.c b/skeletons/ber_decoder.c
index 919dea6..fffd1a1 100644
--- a/skeletons/ber_decoder.c
+++ b/skeletons/ber_decoder.c
@@ -27,7 +27,7 @@
* The BER decoder of any type.
*/
asn_dec_rval_t
-ber_decode(asn_codec_ctx_t *opt_codec_ctx,
+ber_decode(const asn_codec_ctx_t *opt_codec_ctx,
asn_TYPE_descriptor_t *type_descriptor,
void **struct_ptr, const void *ptr, size_t size) {
asn_codec_ctx_t s_codec_ctx;
@@ -62,7 +62,7 @@
* Check the set of <TL<TL<TL...>>> tags matches the definition.
*/
asn_dec_rval_t
-ber_check_tags(asn_codec_ctx_t *opt_codec_ctx,
+ber_check_tags(const asn_codec_ctx_t *opt_codec_ctx,
asn_TYPE_descriptor_t *td, asn_struct_ctx_t *opt_ctx,
const void *ptr, size_t size, int tag_mode, int last_tag_form,
ber_tlv_len_t *last_length, int *opt_tlv_form) {