guard PER references
diff --git a/skeletons/IA5String.c b/skeletons/IA5String.c
index b856d30..fe0c206 100644
--- a/skeletons/IA5String.c
+++ b/skeletons/IA5String.c
@@ -27,8 +27,13 @@
OCTET_STRING_encode_der,
OCTET_STRING_decode_xer_utf8,
OCTET_STRING_encode_xer_utf8,
+#ifdef ASN_DISABLE_PER_SUPPORT
+ 0,
+ 0,
+#else
OCTET_STRING_decode_uper,
OCTET_STRING_encode_uper,
+#endif /* ASN_DISABLE_PER_SUPPORT */
0, /* Use generic outmost tag fetcher */
asn_DEF_IA5String_tags,
sizeof(asn_DEF_IA5String_tags)