diff --git a/mosquitto.c b/mosquitto.c
index a104fbe..9b07ee3 100644
--- a/mosquitto.c
+++ b/mosquitto.c
@@ -886,6 +886,7 @@ PHP_MOSQUITTO_API void php_mosquitto_disconnect_callback(struct mosquitto *mosq,
 
 	MAKE_STD_ZVAL(rc_zval);
 	ZVAL_LONG(rc_zval, rc);
+	params[0] = &rc_zval;
 
 	object->disconnect_callback.params = params;
 	object->disconnect_callback.param_count = 1;