diff --git a/skeletons/asn_codecs_prim.c b/skeletons/asn_codecs_prim.c
index a363f56b3df30719956378f6f60adaa6490482e1..bd5481096d90b7a80b6615f4c852448d8b4e1430 100644
--- a/skeletons/asn_codecs_prim.c
+++ b/skeletons/asn_codecs_prim.c
@@ -217,7 +217,7 @@ xer_decode__primitive_body(void *key, const void *chunk_buf, size_t chunk_size,
 	}
 
 	lead_wsp_size = xer_whitespace_span(chunk_buf, chunk_size);
-	chunk_buf = (char *)chunk_buf + lead_wsp_size;
+	chunk_buf = (const char *)chunk_buf + lead_wsp_size;
 	chunk_size -= lead_wsp_size;
 
 	bret = arg->prim_body_decoder(arg->type_descriptor,