diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index df21cbd..a57761e 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7328,6 +7328,11 @@
     }
 #endif
 
+#if !defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) &&        \
+    !defined(MBEDTLS_SSL_PROTO_DTLS)
+    ((void) ssl);
+#endif
+
     return( (int) max_len );
 }