@@ -22,17 +22,23 @@
 /**
  * @class OFRecursiveMutex OFRecursiveMutex.h ObjFW/OFRecursiveMutex.h
  *
  * @brief A class for creating mutual exclusions which can be entered
  *	  recursively.
+ *
+ * If the mutex is deallocated while being held, it throws an
+ * @ref OFStillLockedException. While this might break ARC's assumption that no
+ * object ever throws in dealloc, it is considered a fatal programmer error
+ * that should terminate the application.
  */
 OF_SUBCLASSING_RESTRICTED
 @interface OFRecursiveMutex: OFObject <OFLocking>
 {
 	OFPlainRecursiveMutex _rmutex;
 	bool _initialized;
 	OFString *_Nullable _name;
+	OF_RESERVE_IVARS(OFRecursiveMutex, 4)
 }
 
 /**
  * @brief Creates a new recursive mutex.
  *