@@ -34,10 +34,11 @@
 /*!
  * @class OFFile OFFile.h ObjFW/OFFile.h
  *
  * @brief A class which provides methods to read and write files.
  */
+OF_SUBCLASSING_RESTRICTED
 @interface OFFile: OFSeekableStream
 #ifdef OF_FILE_HANDLE_IS_FD
     <OFReadyForReadingObserving, OFReadyForWritingObserving>
 #endif
 {