@@ -40,10 +40,11 @@
 /*!
  * @class OFTimer OFTimer.h ObjFW/OFTimer.h
  *
  * @brief A class for creating and firing timers.
  */
+OF_SUBCLASSING_RESTRICTED
 @interface OFTimer: OFObject <OFComparing>
 {
 	OFDate *_fireDate;
 	of_time_interval_t _interval;
 	id _target;