src/Pure/PIDE/session.scala

       case Session.Terminated(result) => result
       case phase => error("Bad session phase after shutdown: " + quote(phase.print))
     }
   }
 
+  def system_output(text: String): Unit =
+    manager.send(new Prover.System_Output(text))
+
   def protocol_command_raw(name: String, args: List[Bytes]): Unit =
     manager.send(Protocol_Command_Raw(name, args))
 
   def protocol_command_args(name: String, args: List[XML.Body]): Unit =
     manager.send(Protocol_Command_Args(name, args))