diff --git a/pjnath/src/pjnath-test/stun.c b/pjnath/src/pjnath-test/stun.c
index 29a8eb1..32a3171 100644
--- a/pjnath/src/pjnath-test/stun.c
+++ b/pjnath/src/pjnath-test/stun.c
@@ -637,7 +637,7 @@
 	}
 
 	pos = cmp_buf(buf, (const pj_uint8_t*)v->pdu, len);
-	if (pos != -1) {
+	if (pos != (unsigned)-1) {
 	    PJ_LOG(1,(THIS_FILE, "    Message mismatch at byte %d", pos));
 	    rc = -1060;
 	    goto on_return;