stuffs

[software/libev.git] / ev.c

diff --git a/ev.c b/ev.c
index 1e54f21b7b54296f806f8a256a813b8c1474c0d3..8a09326689781cc46d8270135b2d77ca54622ec1 100644 (file)
--- a/ev.c
+++ b/ev.c
@@ -1,18 +1,48 @@
+/*
+ * Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *
+ *     * Redistributions in binary form must reproduce the above
+ *       copyright notice, this list of conditions and the following
+ *       disclaimer in the documentation and/or other materials provided
+ *       with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+

 #include <math.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <signal.h>
 #include <math.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <signal.h>

+#include <stddef.h>

 
 #include <stdio.h>
 
 #include <assert.h>
 #include <errno.h>
 
 #include <stdio.h>
 
 #include <assert.h>
 #include <errno.h>

+#include <sys/types.h>
+#include <sys/wait.h>

 #include <sys/time.h>
 #include <time.h>
 
 #include <sys/time.h>
 #include <time.h>
 

-#define HAVE_EPOLL 1
-

 #ifndef HAVE_MONOTONIC
 # ifdef CLOCK_MONOTONIC
 #  define HAVE_MONOTONIC 1
 #ifndef HAVE_MONOTONIC
 # ifdef CLOCK_MONOTONIC
 #  define HAVE_MONOTONIC 1


@@ -33,21 +63,10 @@
 
 #define MIN_TIMEJUMP  1. /* minimum timejump that gets detected (if monotonic clock available) */
 #define MAX_BLOCKTIME 60.
 
 #define MIN_TIMEJUMP  1. /* minimum timejump that gets detected (if monotonic clock available) */
 #define MAX_BLOCKTIME 60.

+#define PID_HASHSIZE  16 /* size of pid hahs table, must be power of two */

 
 #include "ev.h"
 
 
 #include "ev.h"
 

-struct ev_watcher {
-  EV_WATCHER (ev_watcher);
-};
-
-struct ev_watcher_list {
-  EV_WATCHER_LIST (ev_watcher_list);
-};
-
-struct ev_watcher_time {
-  EV_WATCHER_TIME (ev_watcher_time);
-};
-

 typedef struct ev_watcher *W;
 typedef struct ev_watcher_list *WL;
 typedef struct ev_watcher_time *WT;
 typedef struct ev_watcher *W;
 typedef struct ev_watcher_list *WL;
 typedef struct ev_watcher_time *WT;


@@ -96,8 +115,13 @@ get_clock (void)
 #define array_needsize(base,cur,cnt,init)              \
   if ((cnt) > cur)                                     \
     {                                                  \
 #define array_needsize(base,cur,cnt,init)              \
   if ((cnt) > cur)                                     \
     {                                                  \

-      int newcnt = cur ? cur << 1 : 16;                        \
-      fprintf (stderr, "resize(" # base ") from %d to %d\n", cur, newcnt);\
+      int newcnt = cur;                                        \
+      do                                               \
+        {                                              \
+          newcnt = (newcnt << 1) | 4 & ~3;             \
+        }                                              \
+      while ((cnt) > newcnt);                          \
+                                                       \

       base = realloc (base, sizeof (*base) * (newcnt));        \
       init (base + cur, newcnt - cur);                 \
       cur = newcnt;                                    \
       base = realloc (base, sizeof (*base) * (newcnt));        \
       init (base + cur, newcnt - cur);                 \
       cur = newcnt;                                    \


@@ -140,10 +164,13 @@ static int pendingmax, pendingcnt;
 static void
 event (W w, int events)
 {
 static void
 event (W w, int events)
 {

-  w->pending = ++pendingcnt;
-  array_needsize (pendings, pendingmax, pendingcnt, );
-  pendings [pendingcnt - 1].w      = w;
-  pendings [pendingcnt - 1].events = events;
+  if (w->active)
+    {
+      w->pending = ++pendingcnt;
+      array_needsize (pendings, pendingmax, pendingcnt, );
+      pendings [pendingcnt - 1].w      = w;
+      pendings [pendingcnt - 1].events = events;
+    }

 }
 
 static void
 }
 
 static void


@@ -170,6 +197,22 @@ queue_events (W *events, int eventcnt, int type)
     event (events [i], type);
 }
 
     event (events [i], type);
 }
 

+/* called on EBADF to verify fds */
+static void
+fd_recheck (void)
+{
+  int fd;
+
+  for (fd = 0; fd < anfdmax; ++fd)
+    if (anfds [fd].wev)
+      if (fcntl (fd, F_GETFD) == -1 && errno == EBADF)
+        while (anfds [fd].head)
+          {
+            event ((W)anfds [fd].head, EV_ERROR);
+            evio_stop (anfds [fd].head);
+          }
+}
+

 /*****************************************************************************/
 
 static struct ev_timer **timers;
 /*****************************************************************************/
 
 static struct ev_timer **timers;


@@ -295,11 +338,38 @@ siginit (void)
 static struct ev_idle **idles;
 static int idlemax, idlecnt;
 
 static struct ev_idle **idles;
 static int idlemax, idlecnt;
 

+static struct ev_prepare **prepares;
+static int preparemax, preparecnt;
+

 static struct ev_check **checks;
 static int checkmax, checkcnt;
 
 /*****************************************************************************/
 
 static struct ev_check **checks;
 static int checkmax, checkcnt;
 
 /*****************************************************************************/
 

+static struct ev_child *childs [PID_HASHSIZE];
+static struct ev_signal childev;
+
+#ifndef WCONTINUED
+# define WCONTINUED 0
+#endif
+
+static void
+childcb (struct ev_signal *sw, int revents)
+{
+  struct ev_child *w;
+  int pid, status;
+
+  while ((pid = waitpid (-1, &status, WNOHANG | WUNTRACED | WCONTINUED)) != -1)
+    for (w = childs [pid & (PID_HASHSIZE - 1)]; w; w = w->next)
+      if (w->pid == pid || w->pid == -1)
+        {
+          w->status = status;
+          event ((W)w, EV_CHILD);
+        }
+}
+
+/*****************************************************************************/
+

 #if HAVE_EPOLL
 # include "ev_epoll.c"
 #endif
 #if HAVE_EPOLL
 # include "ev_epoll.c"
 #endif


@@ -307,35 +377,53 @@ static int checkmax, checkcnt;
 # include "ev_select.c"
 #endif
 
 # include "ev_select.c"
 #endif
 

+int
+ev_version_major (void)
+{
+  return EV_VERSION_MAJOR;
+}
+
+int
+ev_version_minor (void)
+{
+  return EV_VERSION_MINOR;
+}
+

 int ev_init (int flags)
 {
 int ev_init (int flags)
 {

+  if (!ev_method)
+    {

 #if HAVE_MONOTONIC
 #if HAVE_MONOTONIC

-  {
-    struct timespec ts;
-    if (!clock_gettime (CLOCK_MONOTONIC, &ts))
-      have_monotonic = 1;
-  }
+      {
+        struct timespec ts;
+        if (!clock_gettime (CLOCK_MONOTONIC, &ts))
+          have_monotonic = 1;
+      }

 #endif
 
 #endif
 

-  ev_now = ev_time ();
-  now    = get_clock ();
-  diff   = ev_now - now;
+      ev_now = ev_time ();
+      now    = get_clock ();
+      diff   = ev_now - now;

 
 

-  if (pipe (sigpipe))
-    return 0;
+      if (pipe (sigpipe))
+        return 0;

 
 

-  ev_method = EVMETHOD_NONE;
+      ev_method = EVMETHOD_NONE;

 #if HAVE_EPOLL
 #if HAVE_EPOLL

-  if (ev_method == EVMETHOD_NONE) epoll_init (flags);
+      if (ev_method == EVMETHOD_NONE) epoll_init (flags);

 #endif
 #if HAVE_SELECT
 #endif
 #if HAVE_SELECT

-  if (ev_method == EVMETHOD_NONE) select_init (flags);
+      if (ev_method == EVMETHOD_NONE) select_init (flags);

 #endif
 
 #endif
 

-  if (ev_method)
-    {
-      evw_init (&sigev, sigcb);
-      siginit ();
+      if (ev_method)
+        {
+          evw_init (&sigev, sigcb);
+          siginit ();
+
+          evsignal_init (&childev, childcb, SIGCHLD);
+          evsignal_start (&childev);
+        }

     }
 
   return ev_method;
     }
 
   return ev_method;


@@ -343,17 +431,20 @@ int ev_init (int flags)
 
 /*****************************************************************************/
 
 
 /*****************************************************************************/
 

-void ev_prefork (void)
+void
+ev_prefork (void)

 {
   /* nop */
 }
 
 {
   /* nop */
 }
 

-void ev_postfork_parent (void)
+void
+ev_postfork_parent (void)

 {
   /* nop */
 }
 
 {
   /* nop */
 }
 

-void ev_postfork_child (void)
+void
+ev_postfork_child (void)

 {
 #if HAVE_EPOLL
   if (ev_method == EVMETHOD_EPOLL)
 {
 #if HAVE_EPOLL
   if (ev_method == EVMETHOD_EPOLL)


@@ -396,13 +487,11 @@ fd_reify (void)
 }
 
 static void
 }
 
 static void

-call_pending ()
+call_pending (void)

 {
 {

-  int i;
-
-  for (i = 0; i < pendingcnt; ++i)
+  while (pendingcnt)

     {
     {

-      ANPENDING *p = pendings + i;
+      ANPENDING *p = pendings + --pendingcnt;

 
       if (p->w)
         {
 
       if (p->w)
         {


@@ -410,17 +499,17 @@ call_pending ()
           p->w->cb (p->w, p->events);
         }
     }
           p->w->cb (p->w, p->events);
         }
     }

-
-  pendingcnt = 0;

 }
 
 static void
 }
 
 static void

-timers_reify ()
+timers_reify (void)

 {
   while (timercnt && timers [0]->at <= now)
     {
       struct ev_timer *w = timers [0];
 
 {
   while (timercnt && timers [0]->at <= now)
     {
       struct ev_timer *w = timers [0];
 

+      event ((W)w, EV_TIMEOUT);
+

       /* first reschedule or stop timer */
       if (w->repeat)
         {
       /* first reschedule or stop timer */
       if (w->repeat)
         {


@@ -430,13 +519,11 @@ timers_reify ()
         }
       else
         evtimer_stop (w); /* nonrepeating: stop timer */
         }
       else
         evtimer_stop (w); /* nonrepeating: stop timer */

-
-      event ((W)w, EV_TIMEOUT);

     }
 }
 
 static void
     }
 }
 
 static void

-periodics_reify ()
+periodics_reify (void)

 {
   while (periodiccnt && periodics [0]->at <= ev_now)
     {
 {
   while (periodiccnt && periodics [0]->at <= ev_now)
     {


@@ -457,11 +544,11 @@ periodics_reify ()
 }
 
 static void
 }
 
 static void

-time_jump (ev_tstamp diff)
+periodics_reschedule (ev_tstamp diff)

 {
   int i;
 
 {
   int i;
 

-  /* adjust periodics */
+  /* adjust periodics after time jump */

   for (i = 0; i < periodiccnt; ++i)
     {
       struct ev_periodic *w = periodics [i];
   for (i = 0; i < periodiccnt; ++i)
     {
       struct ev_periodic *w = periodics [i];


@@ -479,14 +566,10 @@ time_jump (ev_tstamp diff)
             }
         }
     }
             }
         }
     }

-
-  /* adjust timers. this is easy, as the offset is the same for all */
-  for (i = 0; i < timercnt; ++i)
-    timers [i]->at += diff;

 }
 
 static void
 }
 
 static void

-time_update ()
+time_update (void)

 {
   int i;
 
 {
   int i;
 


@@ -507,12 +590,19 @@ time_update ()
           ev_now = ev_time ();
         }
 
           ev_now = ev_time ();
         }
 

-      time_jump (diff - odiff);
+      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)
     }
   else
     {
       if (now > ev_now || now < ev_now - MAX_BLOCKTIME - MIN_TIMEJUMP)

-        time_jump (ev_now - now);
+        {
+          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;
     }
 
       now = ev_now;
     }


@@ -523,22 +613,24 @@ int ev_loop_done;
 void ev_loop (int flags)
 {
   double block;
 void ev_loop (int flags)
 {
   double block;

-  ev_loop_done = flags & EVLOOP_ONESHOT;
-
-  if (checkcnt)
-    {
-      queue_events ((W *)checks, checkcnt, EV_CHECK);
-      call_pending ();
-    }
+  ev_loop_done = flags & EVLOOP_ONESHOT ? 1 : 0;

 
   do
     {
 
   do
     {

+      /* queue check watchers (and execute them) */
+      if (preparecnt)
+        {
+          queue_events ((W *)prepares, preparecnt, EV_PREPARE);
+          call_pending ();
+        }
+

       /* update fd-related kernel structures */
       fd_reify ();
 
       /* calculate blocking time */
 
       /* update fd-related kernel structures */
       fd_reify ();
 
       /* calculate blocking time */
 

-      /* we only need this for !monotonic clock, but as we always have timers, we just calculate it every time */
+      /* we only need this for !monotonic clockor timers, but as we basically
+         always have timers, we just calculate it always */

       ev_now = ev_time ();
 
       if (flags & EVLOOP_NONBLOCK || idlecnt)
       ev_now = ev_time ();
 
       if (flags & EVLOOP_NONBLOCK || idlecnt)


@@ -549,7 +641,7 @@ void ev_loop (int flags)
 
           if (timercnt)
             {
 
           if (timercnt)
             {

-              ev_tstamp to = timers [0]->at - get_clock () + method_fudge;
+              ev_tstamp to = timers [0]->at - (have_monotonic ? get_clock () : ev_now) + method_fudge;

               if (block > to) block = to;
             }
 
               if (block > to) block = to;
             }
 


@@ -568,19 +660,23 @@ void ev_loop (int flags)
       time_update ();
 
       /* queue pending timers and reschedule them */
       time_update ();
 
       /* queue pending timers and reschedule them */

-      periodics_reify (); /* absolute timers first */
-      timers_reify (); /* relative timers second */
+      timers_reify (); /* relative timers called last */
+      periodics_reify (); /* absolute timers called first */

 
       /* queue idle watchers unless io or timers are pending */
       if (!pendingcnt)
         queue_events ((W *)idles, idlecnt, EV_IDLE);
 
 
       /* 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);
+      /* queue check watchers, to be executed first */
+      if (checkcnt)
+        queue_events ((W *)checks, checkcnt, EV_CHECK);

 
       call_pending ();
     }
   while (!ev_loop_done);
 
       call_pending ();
     }
   while (!ev_loop_done);

+
+  if (ev_loop_done != 2)
+    ev_loop_done = 0;

 }
 
 /*****************************************************************************/
 }
 
 /*****************************************************************************/


@@ -607,19 +703,25 @@ wlist_del (WL *head, WL elem)
     }
 }
 
     }
 }
 

+static void
+ev_clear (W w)
+{
+  if (w->pending)
+    {
+      pendings [w->pending - 1].w = 0;
+      w->pending = 0;
+    }
+}
+

 static void
 ev_start (W w, int active)
 {
 static void
 ev_start (W w, int active)
 {

-  w->pending = 0;

   w->active = active;
 }
 
 static void
 ev_stop (W w)
 {
   w->active = active;
 }
 
 static void
 ev_stop (W w)
 {

-  if (w->pending)
-    pendings [w->pending - 1].w = 0;
-

   w->active = 0;
 }
 
   w->active = 0;
 }
 


@@ -645,6 +747,7 @@ evio_start (struct ev_io *w)
 void
 evio_stop (struct ev_io *w)
 {
 void
 evio_stop (struct ev_io *w)
 {

+  ev_clear ((W)w);

   if (!ev_is_active (w))
     return;
 
   if (!ev_is_active (w))
     return;
 


@@ -656,7 +759,6 @@ evio_stop (struct ev_io *w)
   fdchanges [fdchangecnt - 1] = w->fd;
 }
 
   fdchanges [fdchangecnt - 1] = w->fd;
 }
 

-

 void
 evtimer_start (struct ev_timer *w)
 {
 void
 evtimer_start (struct ev_timer *w)
 {


@@ -665,6 +767,8 @@ evtimer_start (struct ev_timer *w)
 
   w->at += now;
 
 
   w->at += now;
 

+  assert (("timer repeat value less than zero not allowed", w->repeat >= 0.));
+

   ev_start ((W)w, ++timercnt);
   array_needsize (timers, timermax, timercnt, );
   timers [timercnt - 1] = w;
   ev_start ((W)w, ++timercnt);
   array_needsize (timers, timermax, timercnt, );
   timers [timercnt - 1] = w;


@@ -674,6 +778,7 @@ evtimer_start (struct ev_timer *w)
 void
 evtimer_stop (struct ev_timer *w)
 {
 void
 evtimer_stop (struct ev_timer *w)
 {

+  ev_clear ((W)w);

   if (!ev_is_active (w))
     return;
 
   if (!ev_is_active (w))
     return;
 


@@ -683,15 +788,36 @@ evtimer_stop (struct ev_timer *w)
       downheap ((WT *)timers, timercnt, w->active - 1);
     }
 
       downheap ((WT *)timers, timercnt, w->active - 1);
     }
 

+  w->at = w->repeat;
+

   ev_stop ((W)w);
 }
 
   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;
 
 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;
   /* 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;


@@ -705,6 +831,7 @@ evperiodic_start (struct ev_periodic *w)
 void
 evperiodic_stop (struct ev_periodic *w)
 {
 void
 evperiodic_stop (struct ev_periodic *w)
 {

+  ev_clear ((W)w);

   if (!ev_is_active (w))
     return;
 
   if (!ev_is_active (w))
     return;
 


@@ -740,6 +867,7 @@ evsignal_start (struct ev_signal *w)
 void
 evsignal_stop (struct ev_signal *w)
 {
 void
 evsignal_stop (struct ev_signal *w)
 {

+  ev_clear ((W)w);

   if (!ev_is_active (w))
     return;
 
   if (!ev_is_active (w))
     return;
 


@@ -762,10 +890,34 @@ void evidle_start (struct ev_idle *w)
 
 void evidle_stop (struct ev_idle *w)
 {
 
 void evidle_stop (struct ev_idle *w)
 {

+  ev_clear ((W)w);
+  if (ev_is_active (w))
+    return;
+

   idles [w->active - 1] = idles [--idlecnt];
   ev_stop ((W)w);
 }
 
   idles [w->active - 1] = idles [--idlecnt];
   ev_stop ((W)w);
 }
 

+void evprepare_start (struct ev_prepare *w)
+{
+  if (ev_is_active (w))
+    return;
+
+  ev_start ((W)w, ++preparecnt);
+  array_needsize (prepares, preparemax, preparecnt, );
+  prepares [preparecnt - 1] = w;
+}
+
+void evprepare_stop (struct ev_prepare *w)
+{
+  ev_clear ((W)w);
+  if (ev_is_active (w))
+    return;
+
+  prepares [w->active - 1] = prepares [--preparecnt];
+  ev_stop ((W)w);
+}
+

 void evcheck_start (struct ev_check *w)
 {
   if (ev_is_active (w))
 void evcheck_start (struct ev_check *w)
 {
   if (ev_is_active (w))


@@ -778,13 +930,101 @@ void evcheck_start (struct ev_check *w)
 
 void evcheck_stop (struct ev_check *w)
 {
 
 void evcheck_stop (struct ev_check *w)
 {

+  ev_clear ((W)w);
+  if (ev_is_active (w))
+    return;
+

   checks [w->active - 1] = checks [--checkcnt];
   ev_stop ((W)w);
 }
 
   checks [w->active - 1] = checks [--checkcnt];
   ev_stop ((W)w);
 }
 

+void evchild_start (struct ev_child *w)
+{
+  if (ev_is_active (w))
+    return;
+
+  ev_start ((W)w, 1);
+  wlist_add ((WL *)&childs [w->pid & (PID_HASHSIZE - 1)], (WL)w);
+}
+
+void evchild_stop (struct ev_child *w)
+{
+  ev_clear ((W)w);
+  if (ev_is_active (w))
+    return;
+
+  wlist_del ((WL *)&childs [w->pid & (PID_HASHSIZE - 1)], (WL)w);
+  ev_stop ((W)w);
+}
+

 /*****************************************************************************/
 
 /*****************************************************************************/
 

-#if 1
+struct ev_once
+{
+  struct ev_io io;
+  struct ev_timer to;
+  void (*cb)(int revents, void *arg);
+  void *arg;
+};
+
+static void
+once_cb (struct ev_once *once, int revents)
+{
+  void (*cb)(int revents, void *arg) = once->cb;
+  void *arg = once->arg;
+
+  evio_stop (&once->io);
+  evtimer_stop (&once->to);
+  free (once);
+
+  cb (revents, arg);
+}
+
+static void
+once_cb_io (struct ev_io *w, int revents)
+{
+  once_cb ((struct ev_once *)(((char *)w) - offsetof (struct ev_once, io)), revents);
+}
+
+static void
+once_cb_to (struct ev_timer *w, int revents)
+{
+  once_cb ((struct ev_once *)(((char *)w) - offsetof (struct ev_once, to)), revents);
+}
+
+void
+ev_once (int fd, int events, ev_tstamp timeout, void (*cb)(int revents, void *arg), void *arg)
+{
+  struct ev_once *once = malloc (sizeof (struct ev_once));
+
+  if (!once)
+    cb (EV_ERROR, arg);
+  else
+    {
+      once->cb  = cb;
+      once->arg = arg;
+
+      evw_init (&once->io, once_cb_io);
+
+      if (fd >= 0)
+        {
+          evio_set (&once->io, fd, events);
+          evio_start (&once->io);
+        }
+
+      evw_init (&once->to, once_cb_to);
+
+      if (timeout >= 0.)
+        {
+          evtimer_set (&once->to, timeout, 0.);
+          evtimer_start (&once->to);
+        }
+    }
+}
+
+/*****************************************************************************/
+
+#if 0

 
 struct ev_io wio;
 
 
 struct ev_io wio;