@@ -23,10 +23,11 @@
 /*!
  * @class OFSystemInfo OFSystemInfo.h ObjFW/OFSystemInfo.h
  *
  * @brief A class for querying information about the system.
  */
+OF_SUBCLASSING_RESTRICTED
 @interface OFSystemInfo: OFObject
 #ifdef OF_HAVE_CLASS_PROPERTIES
 @property (class, readonly, nonatomic) size_t pageSize;
 @property (class, readonly, nonatomic) size_t numberOfCPUs;
 @property (class, readonly, nonatomic) OFString *ObjFWVersion;