separate standard alarm from virtual alarm. timeout uses virtual alarm #112

C/exec.c

@@ -1497,9 +1497,9 @@ clean_trail(Term t, Term t0)
 	  } else {
 	    Bind(pt, t);
 	    Yap_WakeUp(pt);
+	    return;
 	  }
 	}
-	return;
       }
       pt1--;
     } else if (IsApplTerm(d1)) {

C/sysbits.c

@@ -1563,6 +1563,24 @@ HandleALRM(int s)
 #endif
 
 
+#if !defined(_WIN32)
+/* this routine is called if the system activated the alarm */
+static RETSIGTYPE
+#if (defined(__svr4__) || defined(__SVR4))
+HandleVTALRM (int s, siginfo_t   *x, ucontext_t *y)
+#else
+HandleVTALRM(int s)
+#endif
+{
+  my_signal (SIGVTALRM, HandleVTALRM);
+  /* force the system to creep */
+  Yap_signal (YAP_VTALARM_SIGNAL);
+  /* now, say what is going on */
+  Yap_PutValue(AtomAlarm, MkAtomTerm(AtomTrue));
+}
+#endif
+
+
 /*
  * This function is called after a normal interrupt had been caught.
  * It allows 6 possibilities: abort, continue, trace, debug, help, exit.
@@ -1651,6 +1669,7 @@ InitSignals (void)
     my_signal (SIGUSR2, ReceiveSignal);
     my_signal (SIGHUP,  ReceiveSignal);
     my_signal (SIGALRM, HandleALRM);
+    my_signal (SIGVTALRM, HandleVTALRM);
 #endif
 #ifdef SIGPIPE
     my_signal (SIGPIPE, ReceiveSignal);
@@ -2779,6 +2798,11 @@ p_first_signal(void)
     UNLOCK(SignalLock);
     return Yap_unify(ARG1, MkAtomTerm(AtomSigAlarm));
   }
+  if (ActiveSignals & YAP_VTALARM_SIGNAL) {
+    ActiveSignals &= ~YAP_VTALARM_SIGNAL;
+    UNLOCK(SignalLock);
+    return Yap_unify(ARG1, MkAtomTerm(AtomSigVTAlarm));
+  }
   if (ActiveSignals & YAP_DELAY_CREEP_SIGNAL) {
     ActiveSignals &= ~(YAP_CREEP_SIGNAL|YAP_DELAY_CREEP_SIGNAL);
 #ifdef THREADS
@@ -2864,6 +2888,9 @@ p_continue_signals(void)
   if (ActiveSignals & YAP_ALARM_SIGNAL) {
     Yap_signal(YAP_ALARM_SIGNAL);
   }
+  if (ActiveSignals & YAP_VTALARM_SIGNAL) {
+    Yap_signal(YAP_VTALARM_SIGNAL);
+  }
   if (ActiveSignals & YAP_CREEP_SIGNAL) {
     Yap_signal(YAP_CREEP_SIGNAL);
   }

H/Yap.h

@@ -578,7 +578,8 @@ typedef enum
   YAP_STATISTICS_SIGNAL = 0x8000,	/* received statistics */
   YAP_DELAY_CREEP_SIGNAL = 0x10000,	/* received a creep but should not do it */
   YAP_AGC_SIGNAL = 0x20000,	/* call atom garbage collector asap */
-  YAP_PIPE_SIGNAL = 0x40000	/* call atom garbage collector asap */
+  YAP_PIPE_SIGNAL = 0x40000,	/* call atom garbage collector asap */
+  YAP_VTALARM_SIGNAL = 0x80000	/* received SIGVTALARM */
 } yap_signals;
 
 #define NUMBER_OF_YAP_FLAGS  LAST_FLAG

H/iatoms.h

@@ -238,6 +238,7 @@
   AtomSigTrace = Yap_LookupAtom("sig_trace");
   AtomSigUsr1 = Yap_LookupAtom("sig_usr1");
   AtomSigUsr2 = Yap_LookupAtom("sig_usr2");
+  AtomSigVTAlarm = Yap_LookupAtom("sig_vtalarm");
   AtomSigWakeUp = Yap_LookupAtom("sig_wake_up");
   AtomSlash = Yap_LookupAtom("/");
   AtomSocket = Yap_LookupAtom("socket");

H/ratoms.h

@@ -240,6 +240,7 @@
   AtomSigTrace = AtomAdjust(AtomSigTrace);
   AtomSigUsr1 = AtomAdjust(AtomSigUsr1);
   AtomSigUsr2 = AtomAdjust(AtomSigUsr2);
+  AtomSigVTAlarm = AtomAdjust(AtomSigVTAlarm);
   AtomSigWakeUp = AtomAdjust(AtomSigWakeUp);
   AtomSlash = AtomAdjust(AtomSlash);
   AtomSocket = AtomAdjust(AtomSocket);

H/tatoms.h

@@ -482,6 +482,8 @@
 #define AtomSigUsr1 Yap_heap_regs->AtomSigUsr1_
   Atom AtomSigUsr2_;
 #define AtomSigUsr2 Yap_heap_regs->AtomSigUsr2_
+  Atom AtomSigVTAlarm_;
+#define AtomSigVTAlarm Yap_heap_regs->AtomSigVTAlarm_
   Atom AtomSigWakeUp_;
 #define AtomSigWakeUp Yap_heap_regs->AtomSigWakeUp_
   Atom AtomSlash_;

library/hacks.yap

@@ -39,13 +39,13 @@ run_formats([Com-Args|StackInfo], Stream) :-
 virtual_alarm(Interval, Goal, Left) :-
 	Interval == 0, !,
 	virtual_alarm(0, 0, Left0, _),
-	on_signal(sig_alarm, _, Goal),
+	on_signal(sig_vtalarm, _, Goal),
 	Left = Left0.
 virtual_alarm(Interval, Goal, Left) :-
 	integer(Interval), !,
-	on_signal(sig_alarm, _, Goal),
+	on_signal(sig_vtalarm, _, Goal),
 	virtual_alarm(Interval, 0, Left, _).
 virtual_alarm(Interval.USecs, Goal, Left.LUSecs) :-
-	on_signal(sig_alarm, _, Goal),
+	on_signal(sig_vtalarm, _, Goal),
 	virtual_alarm(Interval, USecs, Left, LUSecs).
 

misc/ATOMS

@@ -249,6 +249,7 @@ A	SigStatistics		N	"sig_statistic"
 A	SigTrace		N	"sig_trace"
 A	SigUsr1			N	"sig_usr1"
 A	SigUsr2			N	"sig_usr2"
+A	SigVTAlarm		N	"sig_vtalarm"
 A	SigWakeUp		N	"sig_wake_up"
 A	Slash			N	"/"
 A	Socket			N	"socket"

pl/signals.yap

@@ -96,6 +96,8 @@
 % Unix signals
 '$do_signal'(sig_alarm, G) :-
 	'$signal_handler'(sig_alarm, G).
+'$do_signal'(sig_vtalarm, G) :-
+	'$signal_handler'(sig_vtalarm, G).
 '$do_signal'(sig_hup, G) :-
 	'$signal_handler'(sig_hup, G).
 '$do_signal'(sig_usr1, G) :-