From b38505cff25b873c3870669c02695632125e692a Mon Sep 17 00:00:00 2001
From: Ulrich Neumerkel <ulrich@complang.tuwien.ac.at>
Date: Tue, 19 May 2009 18:10:51 +0200
Subject: [PATCH] FIXED: time_out output argument, exceptions (unhappy about
 once)

?- time_out(true,3600,time_out).
yes
   ?- catch(time_out(throw(x),3600,R),x,length(L,L)).
     ERROR!!
     UNHANDLED EXCEPTION - message time_out unknown
---
 library/timeout.yap | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/library/timeout.yap b/library/timeout.yap
index 1ed0bf0f5..607e73f20 100644
--- a/library/timeout.yap
+++ b/library/timeout.yap
@@ -30,14 +30,9 @@ time_out(Goal, Time, Result) :-
 	% enable alarm
 	alarm(T.UT,throw(time_out),_),
 	% launch goal and wait for signal
-	( catch(Goal, time_out, Result = time_out)
-        % make sure to disable alarm
-          ->
-	    alarm(0,_,_)
-	  ;
-	    alarm(0,_,_),
-	    fail
-	),
-	% just couldn't resist...
-	(Result = success -> true ; true).
-
+	call_cleanup(
+		catch( ( Result0 = success, once(Goal) ),
+		       time_out,
+		       Result0 = time_out ),
+		alarm(0,_,_) ),
+	Result = Result0.