X-Git-Url: https://git.llucax.com/software/libev.git/blobdiff_plain/1f3e3ccd18ead040ca58e5eb754ca85018189fd9..49a82c163f76e2916974ec3eac8d395662e7187b:/ev.c

diff --git a/ev.c b/ev.c
index c4935e9..aefc9df 100644
--- a/ev.c
+++ b/ev.c
@@ -1,41 +1,57 @@
 #include <math.h>
 #include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <signal.h>
 
 #include <stdio.h>
 
+#include <assert.h>
 #include <errno.h>
 #include <sys/time.h>
 #include <time.h>
 
-#ifdef CLOCK_MONOTONIC
-# define HAVE_MONOTONIC 1
+#define HAVE_EPOLL 1
+
+#ifndef HAVE_MONOTONIC
+# ifdef CLOCK_MONOTONIC
+#  define HAVE_MONOTONIC 1
+# endif
 #endif
 
-#define HAVE_EPOLL 1
-#define HAVE_REALTIME 1
-#define HAVE_SELECT 0
+#ifndef HAVE_SELECT
+# define HAVE_SELECT 1
+#endif
+
+#ifndef HAVE_EPOLL
+# define HAVE_EPOLL 0
+#endif
+
+#ifndef HAVE_REALTIME
+# define HAVE_REALTIME 1 /* posix requirement, but might be slower */
+#endif
 
+#define MIN_TIMEJUMP  1. /* minimum timejump that gets detected (if monotonic clock available) */
 #define MAX_BLOCKTIME 60.
 
 #include "ev.h"
 
-struct ev_watcher {
-  EV_WATCHER (ev_watcher);
-};
-
-struct ev_watcher_list {
-  EV_WATCHER_LIST (ev_watcher_list);
-};
+typedef struct ev_watcher *W;
+typedef struct ev_watcher_list *WL;
+typedef struct ev_watcher_time *WT;
 
+static ev_tstamp now, diff; /* monotonic clock */
 ev_tstamp ev_now;
 int ev_method;
 
 static int have_monotonic; /* runtime */
 
 static ev_tstamp method_fudge; /* stupid epoll-returns-early bug */
-static void (*method_reify)(void);
+static void (*method_modify)(int fd, int oev, int nev);
 static void (*method_poll)(ev_tstamp timeout);
 
+/*****************************************************************************/
+
 ev_tstamp
 ev_time (void)
 {
@@ -69,12 +85,13 @@ get_clock (void)
   if ((cnt) > cur)					\
     {							\
       int newcnt = cur ? cur << 1 : 16;			\
-      fprintf (stderr, "resize(" # base ") from %d to %d\n", cur, newcnt);\
       base = realloc (base, sizeof (*base) * (newcnt));	\
       init (base + cur, newcnt - cur);			\
       cur = newcnt;					\
     }
 
+/*****************************************************************************/
+
 typedef struct
 {
   struct ev_io *head;
@@ -100,7 +117,7 @@ anfds_init (ANFD *base, int count)
 
 typedef struct
 {
-  struct ev_watcher *w;
+  W w;
   int events;
 } ANPENDING;
 
@@ -108,7 +125,7 @@ static ANPENDING *pendings;
 static int pendingmax, pendingcnt;
 
 static void
-event (struct ev_watcher *w, int events)
+event (W w, int events)
 {
   w->pending = ++pendingcnt;
   array_needsize (pendings, pendingmax, pendingcnt, );
@@ -127,17 +144,31 @@ fd_event (int fd, int events)
       int ev = w->events & events;
 
       if (ev)
-        event ((struct ev_watcher *)w, ev);
+        event ((W)w, ev);
     }
 }
 
+static void
+queue_events (W *events, int eventcnt, int type)
+{
+  int i;
+
+  for (i = 0; i < eventcnt; ++i)
+    event (events [i], type);
+}
+
+/*****************************************************************************/
+
 static struct ev_timer **timers;
 static int timermax, timercnt;
 
+static struct ev_periodic **periodics;
+static int periodicmax, periodiccnt;
+
 static void
-upheap (int k)
+upheap (WT *timers, int k)
 {
-  struct ev_timer *w = timers [k];
+  WT w = timers [k];
 
   while (k && timers [k >> 1]->at > w->at)
     {
@@ -152,15 +183,15 @@ upheap (int k)
 }
 
 static void
-downheap (int k)
+downheap (WT *timers, int N, int k)
 {
-  struct ev_timer *w = timers [k];
+  WT w = timers [k];
 
-  while (k < (timercnt >> 1))
+  while (k < (N >> 1))
     {
       int j = k << 1;
 
-      if (j + 1 < timercnt && timers [j]->at > timers [j + 1]->at)
+      if (j + 1 < N && timers [j]->at > timers [j + 1]->at)
         ++j;
 
       if (w->at <= timers [j]->at)
@@ -175,16 +206,87 @@ downheap (int k)
   timers [k]->active = k + 1;
 }
 
-static struct ev_signal **signals;
-static int signalmax, signalcnt;
+/*****************************************************************************/
+
+typedef struct
+{
+  struct ev_signal *head;
+  sig_atomic_t gotsig;
+} ANSIG;
+
+static ANSIG *signals;
+static int signalmax;
+
+static int sigpipe [2];
+static sig_atomic_t gotsig;
+static struct ev_io sigev;
 
 static void
-signals_init (struct ev_signal **base, int count)
+signals_init (ANSIG *base, int count)
 {
   while (count--)
-    *base++ = 0;
+    {
+      base->head   = 0;
+      base->gotsig = 0;
+      ++base;
+    }
+}
+
+static void
+sighandler (int signum)
+{
+  signals [signum - 1].gotsig = 1;
+
+  if (!gotsig)
+    {
+      gotsig = 1;
+      write (sigpipe [1], &gotsig, 1);
+    }
+}
+
+static void
+sigcb (struct ev_io *iow, int revents)
+{
+  struct ev_signal *w;
+  int sig;
+
+  gotsig = 0;
+  read (sigpipe [0], &revents, 1);
+
+  for (sig = signalmax; sig--; )
+    if (signals [sig].gotsig)
+      {
+        signals [sig].gotsig = 0;
+
+        for (w = signals [sig].head; w; w = w->next)
+          event ((W)w, EV_SIGNAL);
+      }
+}
+
+static void
+siginit (void)
+{
+  fcntl (sigpipe [0], F_SETFD, FD_CLOEXEC);
+  fcntl (sigpipe [1], F_SETFD, FD_CLOEXEC);
+
+  /* rather than sort out wether we really need nb, set it */
+  fcntl (sigpipe [0], F_SETFL, O_NONBLOCK);
+  fcntl (sigpipe [1], F_SETFL, O_NONBLOCK);
+
+  evio_set (&sigev, sigpipe [0], EV_READ);
+  evio_start (&sigev);
 }
 
+/*****************************************************************************/
+
+static struct ev_idle **idles;
+static int idlemax, idlecnt;
+
+static struct ev_check **checks;
+static int checkmax, checkcnt;
+
+/*****************************************************************************/
+
 #if HAVE_EPOLL
 # include "ev_epoll.c"
 #endif
@@ -203,33 +305,81 @@ int ev_init (int flags)
 #endif
 
   ev_now = ev_time ();
+  now    = get_clock ();
+  diff   = ev_now - now;
 
+  if (pipe (sigpipe))
+    return 0;
+
+  ev_method = EVMETHOD_NONE;
 #if HAVE_EPOLL
-  if (epoll_init (flags))
-    return ev_method;
+  if (ev_method == EVMETHOD_NONE) epoll_init (flags);
 #endif
 #if HAVE_SELECT
-  if (select_init (flags))
-    return ev_method;
+  if (ev_method == EVMETHOD_NONE) select_init (flags);
 #endif
 
-  ev_method = EVMETHOD_NONE;
+  if (ev_method)
+    {
+      evw_init (&sigev, sigcb);
+      siginit ();
+    }
+
   return ev_method;
 }
 
+/*****************************************************************************/
+
 void ev_prefork (void)
 {
+  /* nop */
 }
 
 void ev_postfork_parent (void)
 {
+  /* nop */
 }
 
 void ev_postfork_child (void)
 {
 #if HAVE_EPOLL
-  epoll_postfork_child ();
+  if (ev_method == EVMETHOD_EPOLL)
+    epoll_postfork_child ();
 #endif
+
+  evio_stop (&sigev);
+  close (sigpipe [0]);
+  close (sigpipe [1]);
+  pipe (sigpipe);
+  siginit ();
+}
+
+/*****************************************************************************/
+
+static void
+fd_reify (void)
+{
+  int i;
+
+  for (i = 0; i < fdchangecnt; ++i)
+    {
+      int fd = fdchanges [i];
+      ANFD *anfd = anfds + fd;
+      struct ev_io *w;
+
+      int wev = 0;
+
+      for (w = anfd->head; w; w = w->next)
+        wev |= w->events;
+
+      if (anfd->wev != wev)
+        {
+          method_modify (fd, anfd->wev, wev);
+          anfd->wev = wev;
+        }
+    }
+
+  fdchangecnt = 0;
 }
 
 static void
@@ -252,83 +402,191 @@ call_pending ()
 }
 
 static void
-timer_reify (void)
+timers_reify ()
 {
-  while (timercnt && timers [0]->at <= ev_now)
+  while (timercnt && timers [0]->at <= now)
     {
       struct ev_timer *w = timers [0];
 
-          fprintf (stderr, "0 %f, %d c%d\n", w->at, w->active, timercnt);//D
-      /* first reschedule timer */
+      /* first reschedule or stop timer */
       if (w->repeat)
         {
-          fprintf (stderr, "a %f now %f repeat %f, %f\n", w->at, ev_now, w->repeat, w->repeat *1e30);//D
-          if (w->is_abs)
-            w->at += ceil ((ev_now - w->at) / w->repeat + 1.) * w->repeat;
-          else
-            w->at = ev_now + w->repeat;
+          w->at = now + w->repeat;
+          assert (("timer timeout in the past, negative repeat?", w->at > now));
+          downheap ((WT *)timers, timercnt, 0);
+        }
+      else
+        evtimer_stop (w); /* nonrepeating: stop timer */
 
-          fprintf (stderr, "b %f\n", w->at);//D
+      event ((W)w, EV_TIMEOUT);
+    }
+}
+
+static void
+periodics_reify ()
+{
+  while (periodiccnt && periodics [0]->at <= ev_now)
+    {
+      struct ev_periodic *w = periodics [0];
 
-          downheap (0);
+      /* first reschedule or stop timer */
+      if (w->interval)
+        {
+          w->at += floor ((ev_now - w->at) / w->interval + 1.) * w->interval;
+          assert (("periodic timeout in the past, negative interval?", w->at > ev_now));
+          downheap ((WT *)periodics, periodiccnt, 0);
         }
       else
+        evperiodic_stop (w); /* nonrepeating: stop timer */
+
+      event ((W)w, EV_TIMEOUT);
+    }
+}
+
+static void
+periodics_reschedule (ev_tstamp diff)
+{
+  int i;
+
+  /* adjust periodics after time jump */
+  for (i = 0; i < periodiccnt; ++i)
+    {
+      struct ev_periodic *w = periodics [i];
+
+      if (w->interval)
         {
-          fprintf (stderr, "c %f, %d c%d\n", w->at, w->active, timercnt);//D
-        evtimer_stop (w); /* nonrepeating: stop timer */
+          ev_tstamp diff = ceil ((ev_now - w->at) / w->interval) * w->interval;
+
+          if (fabs (diff) >= 1e-4)
+            {
+              evperiodic_stop (w);
+              evperiodic_start (w);
+
+              i = 0; /* restart loop, inefficient, but time jumps should be rare */
+            }
         }
+    }
+}
+
+static void
+time_update ()
+{
+  int i;
 
-      event ((struct ev_watcher *)w, EV_TIMEOUT);
+  ev_now = ev_time ();
+
+  if (have_monotonic)
+    {
+      ev_tstamp odiff = diff;
+
+      for (i = 4; --i; ) /* loop a few times, before making important decisions */
+        {
+          now = get_clock ();
+          diff = ev_now - now;
+
+          if (fabs (odiff - diff) < MIN_TIMEJUMP)
+            return; /* all is well */
+
+          ev_now = ev_time ();
+        }
+
+      periodics_reschedule (diff - odiff);
+      /* no timer adjustment, as the monotonic clock doesn't jump */
+    }
+  else
+    {
+      if (now > ev_now || now < ev_now - MAX_BLOCKTIME - MIN_TIMEJUMP)
+        {
+          periodics_reschedule (ev_now - now);
+
+          /* adjust timers. this is easy, as the offset is the same for all */
+          for (i = 0; i < timercnt; ++i)
+            timers [i]->at += diff;
+        }
+
+      now = ev_now;
     }
 }
 
 int ev_loop_done;
 
-int ev_loop (int flags)
+void ev_loop (int flags)
 {
   double block;
-  ev_loop_done = flags & EVLOOP_ONESHOT;
+  ev_loop_done = flags & EVLOOP_ONESHOT ? 1 : 0;
+
+  if (checkcnt)
+    {
+      queue_events ((W *)checks, checkcnt, EV_CHECK);
+      call_pending ();
+    }
 
   do
     {
       /* update fd-related kernel structures */
-      method_reify (); fdchangecnt = 0;
+      fd_reify ();
 
       /* calculate blocking time */
+
+      /* we only need this for !monotonic clock, but as we always have timers, we just calculate it every time */
       ev_now = ev_time ();
 
-      if (flags & EVLOOP_NONBLOCK)
+      if (flags & EVLOOP_NONBLOCK || idlecnt)
         block = 0.;
-      else if (!timercnt)
-        block = MAX_BLOCKTIME;
       else
         {
-          block = timers [0]->at - ev_now + method_fudge;
+          block = MAX_BLOCKTIME;
+
+          if (timercnt)
+            {
+              ev_tstamp to = timers [0]->at - (have_monotonic ? get_clock () : ev_now) + method_fudge;
+              if (block > to) block = to;
+            }
+
+          if (periodiccnt)
+            {
+              ev_tstamp to = periodics [0]->at - ev_now + method_fudge;
+              if (block > to) block = to;
+            }
+
           if (block < 0.) block = 0.;
-          else if (block > MAX_BLOCKTIME) block = MAX_BLOCKTIME;
         }
 
-      fprintf (stderr, "block %f\n", block);//D
       method_poll (block);
 
-      /* put pending timers into pendign queue and reschedule them */
-      timer_reify ();
+      /* update ev_now, do magic */
+      time_update ();
+
+      /* queue pending timers and reschedule them */
+      periodics_reify (); /* absolute timers first */
+      timers_reify (); /* relative timers second */
+
+      /* queue idle watchers unless io or timers are pending */
+      if (!pendingcnt)
+        queue_events ((W *)idles, idlecnt, EV_IDLE);
+
+      /* queue check and possibly idle watchers */
+      queue_events ((W *)checks, checkcnt, EV_CHECK);
 
-      ev_now = ev_time ();
       call_pending ();
     }
   while (!ev_loop_done);
+
+  if (ev_loop_done != 2)
+    ev_loop_done = 0;
 }
 
+/*****************************************************************************/
+
 static void
-wlist_add (struct ev_watcher_list **head, struct ev_watcher_list *elem)
+wlist_add (WL *head, WL elem)
 {
   elem->next = *head;
   *head = elem;
 }
 
 static void
-wlist_del (struct ev_watcher_list **head, struct ev_watcher_list *elem)
+wlist_del (WL *head, WL elem)
 {
   while (*head)
     {
@@ -343,22 +601,23 @@ wlist_del (struct ev_watcher_list **head, struct ev_watcher_list *elem)
 }
 
 static void
-ev_start (struct ev_watcher *w, int active)
+ev_start (W w, int active)
 {
   w->pending = 0;
   w->active = active;
 }
 
 static void
-ev_stop (struct ev_watcher *w)
+ev_stop (W w)
 {
   if (w->pending)
     pendings [w->pending - 1].w = 0;
 
   w->active = 0;
-  /* nop */
 }
 
+/*****************************************************************************/
+
 void
 evio_start (struct ev_io *w)
 {
@@ -367,9 +626,9 @@ evio_start (struct ev_io *w)
 
   int fd = w->fd;
 
-  ev_start ((struct ev_watcher *)w, 1);
+  ev_start ((W)w, 1);
   array_needsize (anfds, anfdmax, fd + 1, anfds_init);
-  wlist_add ((struct ev_watcher_list **)&anfds[fd].head, (struct ev_watcher_list *)w);
+  wlist_add ((WL *)&anfds[fd].head, (WL)w);
 
   ++fdchangecnt;
   array_needsize (fdchanges, fdchangemax, fdchangecnt, );
@@ -382,52 +641,96 @@ evio_stop (struct ev_io *w)
   if (!ev_is_active (w))
     return;
 
-  wlist_del ((struct ev_watcher_list **)&anfds[w->fd].head, (struct ev_watcher_list *)w);
-  ev_stop ((struct ev_watcher *)w);
+  wlist_del ((WL *)&anfds[w->fd].head, (WL)w);
+  ev_stop ((W)w);
 
   ++fdchangecnt;
   array_needsize (fdchanges, fdchangemax, fdchangecnt, );
   fdchanges [fdchangecnt - 1] = w->fd;
 }
 
+
 void
 evtimer_start (struct ev_timer *w)
 {
   if (ev_is_active (w))
     return;
 
-  fprintf (stderr, "t1 %f a %d\n", w->at, w->is_abs);//D
-  if (w->is_abs)
-    {
-      /* this formula differs from the one in timer_reify becuse we do not round up */
-      if (w->repeat)
-        w->at += ceil ((ev_now - w->at) / w->repeat) * w->repeat;
-    }
-  else
-    w->at += ev_now;
-  fprintf (stderr, "t2 %f a %d\n", w->at, w->is_abs);//D
+  w->at += now;
+
+  assert (("timer repeat value less than zero not allowed", w->repeat >= 0.));
 
-  ev_start ((struct ev_watcher *)w, ++timercnt);
+  ev_start ((W)w, ++timercnt);
   array_needsize (timers, timermax, timercnt, );
   timers [timercnt - 1] = w;
-  upheap (timercnt - 1);
+  upheap ((WT *)timers, timercnt - 1);
 }
 
 void
 evtimer_stop (struct ev_timer *w)
 {
-  fprintf (stderr, "-topping %d, %d\n", w->active, timercnt);//D
   if (!ev_is_active (w))
     return;
 
-  fprintf (stderr, "stopping %d, %d\n", w->active, timercnt);//D
-  if (w->active < timercnt)
+  if (w->active < timercnt--)
+    {
+      timers [w->active - 1] = timers [timercnt];
+      downheap ((WT *)timers, timercnt, w->active - 1);
+    }
+
+  w->at = w->repeat;
+
+  ev_stop ((W)w);
+}
+
+void
+evtimer_again (struct ev_timer *w)
+{
+  if (ev_is_active (w))
+    {
+      if (w->repeat)
+        {
+          w->at = now + w->repeat;
+          downheap ((WT *)timers, timercnt, w->active - 1);
+        }
+      else
+        evtimer_stop (w);
+    }
+  else if (w->repeat)
+    evtimer_start (w);
+}
+
+void
+evperiodic_start (struct ev_periodic *w)
+{
+  if (ev_is_active (w))
+    return;
+
+  assert (("periodic interval value less than zero not allowed", w->interval >= 0.));
+
+  /* this formula differs from the one in periodic_reify because we do not always round up */
+  if (w->interval)
+    w->at += ceil ((ev_now - w->at) / w->interval) * w->interval;
+
+  ev_start ((W)w, ++periodiccnt);
+  array_needsize (periodics, periodicmax, periodiccnt, );
+  periodics [periodiccnt - 1] = w;
+  upheap ((WT *)periodics, periodiccnt - 1);
+}
+
+void
+evperiodic_stop (struct ev_periodic *w)
+{
+  if (!ev_is_active (w))
+    return;
+
+  if (w->active < periodiccnt--)
     {
-      timers [w->active - 1] = timers [--timercnt];
-      downheap (w->active - 1);
+      periodics [w->active - 1] = periodics [periodiccnt];
+      downheap ((WT *)periodics, periodiccnt, w->active - 1);
     }
 
-  ev_stop ((struct ev_watcher *)w);
+  ev_stop ((W)w);
 }
 
 void
@@ -436,9 +739,18 @@ evsignal_start (struct ev_signal *w)
   if (ev_is_active (w))
     return;
 
-  ev_start ((struct ev_watcher *)w, 1);
+  ev_start ((W)w, 1);
   array_needsize (signals, signalmax, w->signum, signals_init);
-  wlist_add ((struct ev_watcher_list **)&signals [w->signum - 1], (struct ev_watcher_list *)w);
+  wlist_add ((WL *)&signals [w->signum - 1].head, (WL)w);
+
+  if (!w->next)
+    {
+      struct sigaction sa;
+      sa.sa_handler = sighandler;
+      sigfillset (&sa.sa_mask);
+      sa.sa_flags = 0;
+      sigaction (w->signum, &sa, 0);
+    }
 }
 
 void
@@ -447,12 +759,50 @@ evsignal_stop (struct ev_signal *w)
   if (!ev_is_active (w))
     return;
 
-  wlist_del ((struct ev_watcher_list **)&signals [w->signum - 1], (struct ev_watcher_list *)w);
-  ev_stop ((struct ev_watcher *)w);
+  wlist_del ((WL *)&signals [w->signum - 1].head, (WL)w);
+  ev_stop ((W)w);
+
+  if (!signals [w->signum - 1].head)
+    signal (w->signum, SIG_DFL);
+}
+
+void evidle_start (struct ev_idle *w)
+{
+  if (ev_is_active (w))
+    return;
+
+  ev_start ((W)w, ++idlecnt);
+  array_needsize (idles, idlemax, idlecnt, );
+  idles [idlecnt - 1] = w;
+}
+
+void evidle_stop (struct ev_idle *w)
+{
+  idles [w->active - 1] = idles [--idlecnt];
+  ev_stop ((W)w);
+}
+
+void evcheck_start (struct ev_check *w)
+{
+  if (ev_is_active (w))
+    return;
+
+  ev_start ((W)w, ++checkcnt);
+  array_needsize (checks, checkmax, checkcnt, );
+  checks [checkcnt - 1] = w;
+}
+
+void evcheck_stop (struct ev_check *w)
+{
+  checks [w->active - 1] = checks [--checkcnt];
+  ev_stop ((W)w);
 }
 
 /*****************************************************************************/
-#if 1
+
+#if 0
+
+struct ev_io wio;
 
 static void
 sin_cb (struct ev_io *w, int revents)
@@ -463,31 +813,63 @@ sin_cb (struct ev_io *w, int revents)
 static void
 ocb (struct ev_timer *w, int revents)
 {
-  fprintf (stderr, "timer %f,%f (%x) (%f) d%p\n", w->at, w->repeat, revents, w->at - ev_time (), w->data);
+  //fprintf (stderr, "timer %f,%f (%x) (%f) d%p\n", w->at, w->repeat, revents, w->at - ev_time (), w->data);
+  evtimer_stop (w);
+  evtimer_start (w);
 }
 
-int main (void)
+static void
+scb (struct ev_signal *w, int revents)
 {
-  struct ev_io sin;
+  fprintf (stderr, "signal %x,%d\n", revents, w->signum);
+  evio_stop (&wio);
+  evio_start (&wio);
+}
+
+static void
+gcb (struct ev_signal *w, int revents)
+{
+  fprintf (stderr, "generic %x\n", revents);
+
+}
 
+int main (void)
+{
   ev_init (0);
 
-  evw_init (&sin, sin_cb, 55);
-  evio_set (&sin, 0, EV_READ);
-  evio_start (&sin);
+  evio_init (&wio, sin_cb, 0, EV_READ);
+  evio_start (&wio);
 
-  struct ev_timer t[1000];
+  struct ev_timer t[10000];
 
+#if 0
   int i;
-  for (i = 0; i < 1000; ++i)
+  for (i = 0; i < 10000; ++i)
     {
       struct ev_timer *w = t + i;
       evw_init (w, ocb, i);
-      evtimer_set_rel (w, drand48 (), 0);
+      evtimer_init_abs (w, ocb, drand48 (), 0.99775533);
       evtimer_start (w);
       if (drand48 () < 0.5)
         evtimer_stop (w);
     }
+#endif
+
+  struct ev_timer t1;
+  evtimer_init (&t1, ocb, 5, 10);
+  evtimer_start (&t1);
+
+  struct ev_signal sig;
+  evsignal_init (&sig, scb, SIGQUIT);
+  evsignal_start (&sig);
+
+  struct ev_check cw;
+  evcheck_init (&cw, gcb);
+  evcheck_start (&cw);
+
+  struct ev_idle iw;
+  evidle_init (&iw, gcb);
+  evidle_start (&iw);
 
   ev_loop (0);