fix bad behavior of time_out by making sure interrupts are disabled during critical operation, up

to setting a throw.

library/timeout.yap

@@ -24,15 +24,38 @@
 %
 % not the nicest program I've ever seen.
 %
+%
+% I cannot use setup_call_cleanup because I can only take interrupts *after* I set up
+% the catcher, so I have to do the dirty deed myself.
+%
 time_out(Goal, Time, Result) :-
 	T is Time//1000,
 	UT is (Time mod 1000)*1000,
+	yap_hacks:disable_interrupts,
 	% enable alarm
 	alarm(T.UT,throw(time_out),_),
 	% launch goal and wait for signal
-	call_cleanup(
-		catch( ( Result0 = success, once(Goal) ),
+	catch( run_goal(Goal, Result0),
 	       time_out,
 	       Result0 = time_out ),
-		alarm(0,_,_) ),
 	Result = Result0.
+
+run_goal(Goal, Result0) :-
+	% we can only enable interrupts after alarm was been enabled.
+	yap_hacks:enable_interrupts,
+	Result0 = success,
+	call(Goal),
+	!,
+	% make sure we're not getting an extraneous interrupt if we terminate early....
+	yap_hacks:disable_interrupts.
+	alarm(0,_,_),
+	true.
+run_goal(Goal, Result0) :-
+	yap_hacks:disable_interrupts,
+	% make sure we're not getting an extraneous interrupt if we terminate early....
+	alarm(0,_,_),
+	fail.
+
+complete_time_out :-
+	alarm(0,_,_),
+	yap_hacks:enable_interrupts.