diff --git a/skeletons/OCTET_STRING.c b/skeletons/OCTET_STRING.c
index 57e17af..19ae95d 100644
--- a/skeletons/OCTET_STRING.c
+++ b/skeletons/OCTET_STRING.c
@@ -87,7 +87,7 @@
 			} else {					\
 				RETURN(RC_FAIL);			\
 			}						\
-			ASN_DEBUG("Reallocating into %ld", _ns);	\
+			ASN_DEBUG("Reallocating into %ld", (long)_ns);	\
 		}							\
 		memcpy(st->buf + st->size, bufptr, _bs);		\
 		/* Convenient nul-termination */			\