diff --git a/skeletons/IA5String.c b/skeletons/IA5String.c
index 32a7a7f..c4da875 100644
--- a/skeletons/IA5String.c
+++ b/skeletons/IA5String.c
@@ -48,10 +48,10 @@
 		for(; buf < end; buf++) {
 			if(*buf > 0x7F) {
 				_ASN_ERRLOG(app_errlog, app_key,
-					"%s: value byte %d out of range: "
+					"%s: value byte %ld out of range: "
 					"%d > 127 (%s:%d)",
 					td->name,
-					(buf - st->buf) + 1,
+					(long)((buf - st->buf) + 1),
 					*buf,
 					__FILE__, __LINE__);
 				return -1;