@@ -18,10 +18,12 @@
 
 #ifndef OF_HAVE_SOCKETS
 # error No sockets available!
 #endif
 
+OF_ASSUME_NONNULL_BEGIN
+
 /*!
  * @class OFAlreadyConnectedException \
  *	  OFAlreadyConnectedException.h ObjFW/OFAlreadyConnectedException.h
  *
  * @brief An exception indicating an attempt to connect or bind an already
@@ -33,23 +35,25 @@
 }
 
 /*!
  * The socket which is already connected.
  */
-@property (readonly, nonatomic) id socket;
+@property OF_NULLABLE_PROPERTY (readonly, nonatomic) id socket;
 
 /*!
  * @brief Creates a new, autoreleased already connected exception.
  *
  * @param socket The socket which is already connected
  * @return A new, autoreleased already connected exception
  */
-+ (instancetype)exceptionWithSocket: (id)socket;
++ (instancetype)exceptionWithSocket: (nullable id)socket;
 
 /*!
  * @brief Initializes an already allocated already connected exception.
  *
  * @param socket The socket which is already connected
  * @return An initialized already connected exception
  */
-- initWithSocket: (id)socket;
+- initWithSocket: (nullable id)socket;
 @end
+
+OF_ASSUME_NONNULL_END