diff --git a/include/sys/socket.h b/include/sys/socket.h
index aacb0540b..65d1a8128 100644
--- a/include/sys/socket.h
+++ b/include/sys/socket.h
@@ -61,6 +61,8 @@ _PROTOTYPE( int getsockname, (int _socket,
 				socklen_t *_RESTRICT _address_len)	);
 _PROTOTYPE( int setsockopt,(int _socket, int _level, int _option_name,
 		const void *_option_value, socklen_t _option_len)	);
+_PROTOTYPE( int getsockopt, (int _socket, int _level, int _option_name,
+        void *_RESTRICT _option_value, socklen_t *_RESTRICT _option_len));
 _PROTOTYPE( int listen, (int _socket, int _backlog)			);
 _PROTOTYPE( ssize_t recvfrom, (int _socket, void *_RESTRICT _buffer,
 	size_t _length, int _flags, struct sockaddr *_RESTRICT _address,