src/Pure/PIDE/command.ML

 val _ =
   print_function "Execution.print"
     (fn {args, exec_id, ...} =>
       if null args then
         SOME {delay = NONE, pri = 1, persistent = false, strict = true,
-          print_fn = fn _ => fn _ => Execution.apply_prints exec_id}
+          print_fn = fn _ => fn _ => Execution.fork_prints exec_id}
       else NONE);
 
 val _ =
   print_function "print_state"
     (fn {command_name, ...} =>