diff -r 42d56a6dec6e -r ae5bb6001afb src/HOL/Tools/ATP/watcher.ML
--- a/src/HOL/Tools/ATP/watcher.ML	Tue Sep 20 18:42:56 2005 +0200
+++ b/src/HOL/Tools/ATP/watcher.ML	Tue Sep 20 18:43:39 2005 +0200
@@ -270,7 +270,9 @@
 fun prems_string_of th =
   Meson.concat_with_and (map (Sign.string_of_term (sign_of_thm th)) (prems_of th))
 
-fun killChildren procs = List.app (ignore o Unix.reap) procs;
+fun killChild proc = (Unix.kill(proc, Posix.Signal.kill); Unix.reap proc);
+
+fun killChildren procs = List.app (ignore o killChild) procs;
 
 fun setupWatcher (thm,clause_arr) = 
   let