diff --git a/skeletons/IA5String.c b/skeletons/IA5String.c
index 32a7a7f82da4c4980c4cf3e757b93aa4c52d5f65..c4da875a51df993e54562b7c7b504e31118a70b1 100644
--- a/skeletons/IA5String.c
+++ b/skeletons/IA5String.c
@@ -48,10 +48,10 @@ IA5String_constraint(asn_TYPE_descriptor_t *td, const void *sptr,
 		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;
diff --git a/skeletons/NumericString.c b/skeletons/NumericString.c
index dbff6e21f77e8a06bd3e58ca31a4934adcc1462c..39404c25ed492acc20964d94d2783dd7ced020c2 100644
--- a/skeletons/NumericString.c
+++ b/skeletons/NumericString.c
@@ -54,10 +54,10 @@ NumericString_constraint(asn_TYPE_descriptor_t *td, const void *sptr,
 				continue;
 			}
 			_ASN_ERRLOG(app_errlog, app_key,
-				"%s: value byte %d (%d) "
+				"%s: value byte %ld (%d) "
 				"not in NumericString alphabet (%s:%d)",
 				td->name,
-				(buf - st->buf) + 1,
+				(long)((buf - st->buf) + 1),
 				*buf,
 				__FILE__, __LINE__);
 			return -1;
diff --git a/skeletons/PrintableString.c b/skeletons/PrintableString.c
index dc363d84699a30edb79d253e4a2492b604a4a6a9..bc48c0f87994c2ec36bdccb3779c1e0422d42b8c 100644
--- a/skeletons/PrintableString.c
+++ b/skeletons/PrintableString.c
@@ -72,11 +72,11 @@ PrintableString_constraint(asn_TYPE_descriptor_t *td, const void *sptr,
 		for(; buf < end; buf++) {
 			if(!_PrintableString_alphabet[*buf]) {
 				_ASN_ERRLOG(app_errlog, app_key,
-					"%s: value byte %d (%d) "
+					"%s: value byte %ld (%d) "
 					"not in PrintableString alphabet "
 					"(%s:%d)",
 					td->name,
-					(buf - st->buf) + 1,
+					(long)((buf - st->buf) + 1),
 					*buf,
 					__FILE__, __LINE__);
 				return -1;
diff --git a/skeletons/VisibleString.c b/skeletons/VisibleString.c
index 7170b542a70214fe8edb1ec4008cf7a7971616ff..30f294558fb868a5ecf2cb71b63cd29e13802523 100644
--- a/skeletons/VisibleString.c
+++ b/skeletons/VisibleString.c
@@ -51,10 +51,10 @@ VisibleString_constraint(asn_TYPE_descriptor_t *td, const void *sptr,
 		for(; buf < end; buf++) {
 			if(*buf < 0x20 || *buf > 0x7e) {
 				_ASN_ERRLOG(app_errlog, app_key,
-					"%s: value byte %d (%d) "
+					"%s: value byte %ld (%d) "
 					"not in VisibleString alphabet (%s:%d)",
 					td->name,
-					(buf - st->buf) + 1,
+					(long)((buf - st->buf) + 1),
 					*buf,
 					__FILE__, __LINE__);
 				return -1;