--- a/src/Pure/Concurrent/multithreading.ML Mon Feb 19 10:35:53 2018 +0100
+++ b/src/Pure/Concurrent/multithreading.ML Mon Feb 19 11:13:25 2018 +0100
@@ -9,6 +9,7 @@
val max_threads: unit -> int
val max_threads_update: int -> unit
val enabled: unit -> bool
+ val relevant: 'a list -> bool
val sync_wait: Time.time option -> ConditionVar.conditionVar -> Mutex.mutex -> bool Exn.result
val trace: int ref
val tracing: int -> (unit -> string) -> unit
@@ -41,6 +42,8 @@
fun max_threads_update m = max_threads_state := max_threads_result m;
fun enabled () = max_threads () > 1;
+val relevant = (fn [] => false | [_] => false | _ => enabled ());
+
end;