diff --git a/include/polarssl/ssl.h b/include/polarssl/ssl.h
index 012b89a..678deb8 100644
--- a/include/polarssl/ssl.h
+++ b/include/polarssl/ssl.h
@@ -1831,6 +1831,8 @@
 #if defined(POLARSSL_SSL_PROTO_DTLS)
     if( ssl->transport == SSL_TRANSPORT_DATAGRAM )
         return( 13 );
+#else
+    ((void) ssl);
 #endif
     return( 5 );
 }