diff --git a/src/mzscheme/src/error.c b/src/mzscheme/src/error.c
index ecc556cf00..eae21a0e4b 100644
--- a/src/mzscheme/src/error.c
+++ b/src/mzscheme/src/error.c
@@ -2880,18 +2880,15 @@ void scheme_log_message(Scheme_Logger *logger, int level, char *buffer, long len
             SCHEME_VEC_ELS(msg)[1] = v;
             SCHEME_VEC_ELS(msg)[2] = (data ? data : scheme_false);
           }
-          if (!lr->tail
-              && scheme_try_channel_put(lr->ch, msg)) {
-            /* delivered immediately */
-          } else {
-            /* enqueue */
-            q = scheme_make_raw_pair(msg, NULL);
-            if (lr->tail)
-              SCHEME_CDR(lr->tail) = q;
-            else
-              lr->head = q;
-            lr->tail = q;
-          }
+          
+          /* enqueue */
+          q = scheme_make_raw_pair(msg, NULL);
+          if (lr->tail)
+            SCHEME_CDR(lr->tail) = q;
+          else
+            lr->head = q;
+          lr->tail = q;
+          scheme_post_sema(lr->sema);
         }
       }
       queue = SCHEME_CDR(queue);
@@ -3048,7 +3045,7 @@ make_log_reader(int argc, Scheme_Object *argv[])
 {
   Scheme_Logger *logger;
   Scheme_Log_Reader *lr;
-  Scheme_Object *ch, *q;
+  Scheme_Object *sema, *q;
   int level;
 
   if (!SAME_TYPE(SCHEME_TYPE(argv[0]), scheme_logger_type))
@@ -3061,8 +3058,8 @@ make_log_reader(int argc, Scheme_Object *argv[])
   lr->so.type = scheme_log_reader_type;
   lr->want_level = level;
 
-  ch = scheme_make_channel();
-  lr->ch = ch;
+  sema = scheme_make_sema(0);
+  lr->sema = sema;
 
   /* Pair a weak reference to the reader with a strong reference to the
      channel. Channel gets are wrapped to reference the reader. That way,
@@ -3070,7 +3067,7 @@ make_log_reader(int argc, Scheme_Object *argv[])
      reader. */
 
   q = scheme_make_raw_pair(scheme_make_pair(scheme_make_weak_box((Scheme_Object *)lr), 
-                                            ch),
+                                            sema),
                            logger->readers);
   logger->readers = q;
   *logger->timestamp += 1;
@@ -3086,12 +3083,7 @@ log_reader_p(int argc, Scheme_Object *argv[])
           : scheme_false);
 }
 
-static Scheme_Object *id_that_preserves_reader(void *data, int argc, Scheme_Object **argv)
-{
-  return argv[0];
-}
-
-static int log_reader_get(Scheme_Object *_lr, Scheme_Schedule_Info *sinfo)
+static Scheme_Object *dequeue_log(Scheme_Object *_lr)
 {
   Scheme_Log_Reader *lr = (Scheme_Log_Reader *)_lr;
 
@@ -3101,18 +3093,20 @@ static int log_reader_get(Scheme_Object *_lr, Scheme_Schedule_Info *sinfo)
     lr->head = SCHEME_CDR(lr->head);
     if (!lr->head)
       lr->tail = NULL;
-    scheme_set_sync_target(sinfo, v, NULL, NULL, 0, 0);
-    return 1;
+    return v;
   } else {
-    Scheme_Object *w;
-
-    w = scheme_make_closed_prim(id_that_preserves_reader, lr);
-
-    scheme_set_sync_target(sinfo, lr->ch, w, NULL, 0, 0);
-    return 0;
+    scheme_signal_error("empty log-reader queue!?");
+    return NULL;
   }
 }
 
+static int log_reader_get(Scheme_Object *_lr, Scheme_Schedule_Info *sinfo)
+{
+  Scheme_Log_Reader *lr = (Scheme_Log_Reader *)_lr;
+  scheme_set_sync_target(sinfo, lr->sema, (Scheme_Object *)lr, NULL, 0, 1, dequeue_log);
+  return 0;
+}
+
 /***********************************************************************/
 
 void
diff --git a/src/mzscheme/src/mzmark.c b/src/mzscheme/src/mzmark.c
index dbd985a514..517bf9029c 100644
--- a/src/mzscheme/src/mzmark.c
+++ b/src/mzscheme/src/mzmark.c
@@ -2677,7 +2677,7 @@ static int mark_log_reader_SIZE(void *p) {
 
 static int mark_log_reader_MARK(void *p) {
   Scheme_Log_Reader *lr = (Scheme_Log_Reader *)p;
-  gcMARK(lr->ch);
+  gcMARK(lr->sema);
   gcMARK(lr->head);
   gcMARK(lr->tail);
   return
@@ -2686,7 +2686,7 @@ static int mark_log_reader_MARK(void *p) {
 
 static int mark_log_reader_FIXUP(void *p) {
   Scheme_Log_Reader *lr = (Scheme_Log_Reader *)p;
-  gcFIXUP(lr->ch);
+  gcFIXUP(lr->sema);
   gcFIXUP(lr->head);
   gcFIXUP(lr->tail);
   return
@@ -4235,6 +4235,7 @@ static int mark_syncing_MARK(void *p) {
   gcMARK(w->wrapss);
   gcMARK(w->nackss);
   gcMARK(w->reposts);
+  gcMARK(w->accepts);
   gcMARK(w->disable_break);
 
   return
@@ -4248,6 +4249,7 @@ static int mark_syncing_FIXUP(void *p) {
   gcFIXUP(w->wrapss);
   gcFIXUP(w->nackss);
   gcFIXUP(w->reposts);
+  gcFIXUP(w->accepts);
   gcFIXUP(w->disable_break);
 
   return
diff --git a/src/mzscheme/src/mzmarksrc.c b/src/mzscheme/src/mzmarksrc.c
index 9bc1bff78c..f3611ec6db 100644
--- a/src/mzscheme/src/mzmarksrc.c
+++ b/src/mzscheme/src/mzmarksrc.c
@@ -1063,7 +1063,7 @@ mark_logger {
 mark_log_reader {
  mark:
   Scheme_Log_Reader *lr = (Scheme_Log_Reader *)p;
-  gcMARK(lr->ch);
+  gcMARK(lr->sema);
   gcMARK(lr->head);
   gcMARK(lr->tail);
  size:
@@ -1724,6 +1724,7 @@ mark_syncing {
   gcMARK(w->wrapss);
   gcMARK(w->nackss);
   gcMARK(w->reposts);
+  gcMARK(w->accepts);
   gcMARK(w->disable_break);
 
  size:
diff --git a/src/mzscheme/src/network.c b/src/mzscheme/src/network.c
index 6f8b895547..55f386009e 100644
--- a/src/mzscheme/src/network.c
+++ b/src/mzscheme/src/network.c
@@ -2465,7 +2465,7 @@ static int tcp_check_accept_evt(Scheme_Object *ae, Scheme_Schedule_Info *sinfo)
     tcp_accept(1, a);
     a[0] = scheme_current_thread->ku.multiple.array[0];
     a[1] = scheme_current_thread->ku.multiple.array[1];
-    scheme_set_sync_target(sinfo, scheme_build_list(2, a), NULL, NULL, 0, 0);
+    scheme_set_sync_target(sinfo, scheme_build_list(2, a), NULL, NULL, 0, 0, NULL);
     return 1;
   } else
     return 0;
@@ -3359,7 +3359,7 @@ static int udp_evt_check_ready(Scheme_Object *_uw, Scheme_Schedule_Info *sinfo)
       if (do_udp_recv("udp-receive!-evt", uw->udp, 
 		      uw->str, uw->offset, uw->offset + uw->len, 
 		      0, v)) {
-	scheme_set_sync_target(sinfo, scheme_build_list(3, v), NULL, NULL, 0, 0);
+	scheme_set_sync_target(sinfo, scheme_build_list(3, v), NULL, NULL, 0, 0, NULL);
 	return 1;
       } else
 	return 0;
@@ -3374,7 +3374,7 @@ static int udp_evt_check_ready(Scheme_Object *_uw, Scheme_Schedule_Info *sinfo)
 			 uw->dest_addr, uw->dest_addr_len,
 			 0);
       if (SCHEME_TRUEP(r)) {
-	scheme_set_sync_target(sinfo, scheme_void, NULL, NULL, 0, 0);
+	scheme_set_sync_target(sinfo, scheme_void, NULL, NULL, 0, 0, NULL);
 	return 1;
       } else
 	return 0;
diff --git a/src/mzscheme/src/port.c b/src/mzscheme/src/port.c
index d1dbc944f2..c2cb4f14b0 100644
--- a/src/mzscheme/src/port.c
+++ b/src/mzscheme/src/port.c
@@ -2135,7 +2135,7 @@ Scheme_Object *scheme_progress_evt(Scheme_Object *port)
 
 static int progress_evt_ready(Scheme_Object *evt, Scheme_Schedule_Info *sinfo)
 {
-  scheme_set_sync_target(sinfo, SCHEME_PTR2_VAL(evt), evt, NULL, 0, 1);
+  scheme_set_sync_target(sinfo, SCHEME_PTR2_VAL(evt), evt, NULL, 0, 1, NULL);
   return 0;
 }
 
@@ -2642,7 +2642,7 @@ static int rw_evt_ready(Scheme_Object *_rww, Scheme_Schedule_Info *sinfo)
 
     v = ws(op, rww->v, 1);
     if (v) {
-      scheme_set_sync_target(sinfo, scheme_true, NULL, NULL, 0, 0);
+      scheme_set_sync_target(sinfo, scheme_true, NULL, NULL, 0, 0, NULL);
       return 1;
     } else	
       return 0;
@@ -2655,7 +2655,7 @@ static int rw_evt_ready(Scheme_Object *_rww, Scheme_Schedule_Info *sinfo)
     else if (!v && rww->size)
       return 0;
     else {
-      scheme_set_sync_target(sinfo, scheme_make_integer(v), NULL, NULL, 0, 0);
+      scheme_set_sync_target(sinfo, scheme_make_integer(v), NULL, NULL, 0, 0, NULL);
       return 1;
     }
   }
diff --git a/src/mzscheme/src/portfun.c b/src/mzscheme/src/portfun.c
index da8171c61e..2ba62999b4 100644
--- a/src/mzscheme/src/portfun.c
+++ b/src/mzscheme/src/portfun.c
@@ -1221,7 +1221,7 @@ static long user_read_result(const char *who, Scheme_Input_Port *port,
 	   when the read/peek (at some offset) succeeds. */
 	if (nonblock > 0) {
 	  if (sinfo) {
-	    scheme_set_sync_target(sinfo, val, (Scheme_Object *)port, NULL, 0, 1);
+	    scheme_set_sync_target(sinfo, val, (Scheme_Object *)port, NULL, 0, 1, NULL);
 	    return 0;
 	  } else {
 	    /* Poll: */
@@ -1655,7 +1655,7 @@ int scheme_user_port_write_probably_ready(Scheme_Output_Port *port, Scheme_Sched
 
   val = uop->evt;
 
-  scheme_set_sync_target(sinfo, val, (Scheme_Object *)port, NULL, 0, 1);
+  scheme_set_sync_target(sinfo, val, (Scheme_Object *)port, NULL, 0, 1, NULL);
   return 0;
 
 }
diff --git a/src/mzscheme/src/schpriv.h b/src/mzscheme/src/schpriv.h
index 809079cc14..84ea52b821 100644
--- a/src/mzscheme/src/schpriv.h
+++ b/src/mzscheme/src/schpriv.h
@@ -447,9 +447,13 @@ typedef struct {
   short is_poll;
 } Scheme_Schedule_Info;
 
+typedef Scheme_Object *(*Scheme_Accept_Sync)(Scheme_Object *wrap);
+
 void scheme_set_sync_target(Scheme_Schedule_Info *sinfo, Scheme_Object *target,
 			    Scheme_Object *wrap, Scheme_Object *nack,
-			    int repost, int retry);
+			    int repost, int retry, Scheme_Accept_Sync accept);
+struct Syncing;
+void scheme_accept_sync(struct Syncing *syncing, int i);
 
 typedef int (*Scheme_Ready_Fun_FPC)(Scheme_Object *o, Scheme_Schedule_Info *sinfo);
 
@@ -1327,6 +1331,7 @@ typedef struct Syncing {
   Scheme_Object **wrapss;
   Scheme_Object **nackss;
   char *reposts;
+  Scheme_Accept_Sync *accepts;
 
   Scheme_Thread *disable_break; /* when result is set */
 } Syncing;
@@ -2770,13 +2775,13 @@ struct Scheme_Logger {
   int want_level;
   long *timestamp, local_timestamp; /* determines when want_level is up-to-date */
   int syslog_level, stderr_level;
-  Scheme_Object *readers; /* list of (cons (make-weak-box <reader>) <channel>) */
+  Scheme_Object *readers; /* list of (cons (make-weak-box <reader>) <sema>) */
 };
 
 typedef struct Scheme_Log_Reader {
   Scheme_Object so;
   int want_level;
-  Scheme_Object *ch;
+  Scheme_Object *sema;
   Scheme_Object *head, *tail;
 } Scheme_Log_Reader;
 
diff --git a/src/mzscheme/src/sema.c b/src/mzscheme/src/sema.c
index 6fe168cead..5a24a9b5a5 100644
--- a/src/mzscheme/src/sema.c
+++ b/src/mzscheme/src/sema.c
@@ -301,6 +301,8 @@ void scheme_post_sema(Scheme_Object *o)
 	    consumed = 1;
 	  } else
 	    consumed = 0;
+          if (w->syncing->accepts && w->syncing->accepts[w->syncing_i])
+            scheme_accept_sync(w->syncing, w->syncing_i);
 	} else {
 	  /* In this case, we will remove the syncer from line, but
 	     someone else might grab the post. This is unfair, but it
@@ -481,7 +483,7 @@ static void ext_get_into_line(Scheme_Object *ch, Scheme_Schedule_Info *sinfo)
 
   get_into_line((Scheme_Sema *)ch, w);
 
-  scheme_set_sync_target(sinfo, (Scheme_Object *)w, NULL, NULL, 0, 0);
+  scheme_set_sync_target(sinfo, (Scheme_Object *)w, NULL, NULL, 0, 0, NULL);
 }
 
 void scheme_get_outof_line(Scheme_Channel_Syncer *ch_w)
@@ -637,6 +639,8 @@ int scheme_wait_semas_chs(int n, Scheme_Object **o, int just_try, Syncing *synci
 	if (semas[i]->value) {
 	  if ((semas[i]->value > 0) && (!syncing || !syncing->reposts || !syncing->reposts[i]))
 	    --semas[i]->value;
+          if (syncing && syncing->accepts && syncing->accepts[i])
+            scheme_accept_sync(syncing, i);
 	  break;
 	}
       } else if (semas[i]->so.type == scheme_never_evt_type) {
@@ -811,6 +815,8 @@ int scheme_wait_semas_chs(int n, Scheme_Object **o, int just_try, Syncing *synci
 	    if (semas[i]->value) {
 	      if ((semas[i]->value > 0) && (!syncing || !syncing->reposts || !syncing->reposts[i]))
 		--semas[i]->value;
+              if (syncing && syncing->accepts && syncing->accepts[i])
+                scheme_accept_sync(syncing, i);
 	      break;
 	    }
 	  }  else if (semas[i]->so.type == scheme_never_evt_type) {
@@ -988,7 +994,7 @@ static int channel_get_ready(Scheme_Object *ch, Scheme_Schedule_Info *sinfo)
   Scheme_Object *result;
 
   if (try_channel((Scheme_Sema *)ch, (Syncing *)sinfo->current_syncing, -1, &result)) {
-    scheme_set_sync_target(sinfo, result, NULL, NULL, 0, 0);
+    scheme_set_sync_target(sinfo, result, NULL, NULL, 0, 0, NULL);
     return 1;
   }
 
@@ -1184,7 +1190,7 @@ static int thread_recv_ready(Scheme_Object *ch, Scheme_Schedule_Info *sinfo)
 
   make_mbox_sema(p);
 
-  scheme_set_sync_target(sinfo, p->mbox_sema, thread_recv_evt, NULL, 1, 1);
+  scheme_set_sync_target(sinfo, p->mbox_sema, thread_recv_evt, NULL, 1, 1, NULL);
 
   return 0;
 }
diff --git a/src/mzscheme/src/struct.c b/src/mzscheme/src/struct.c
index b737c4f050..ab0d92ec59 100644
--- a/src/mzscheme/src/struct.c
+++ b/src/mzscheme/src/struct.c
@@ -999,7 +999,7 @@ static int evt_struct_is_ready(Scheme_Object *o, Scheme_Schedule_Info *sinfo)
     } else {
       v = (Scheme_Object *)scheme_output_port_record(o);
     }
-    scheme_set_sync_target(sinfo, v, NULL, NULL, 0, 1);
+    scheme_set_sync_target(sinfo, v, NULL, NULL, 0, 1, NULL);
     return 0;
   }
 
@@ -1007,7 +1007,7 @@ static int evt_struct_is_ready(Scheme_Object *o, Scheme_Schedule_Info *sinfo)
     v = ((Scheme_Structure *)o)->slots[SCHEME_INT_VAL(v)];
 
   if (scheme_is_evt(v)) {
-    scheme_set_sync_target(sinfo, v, NULL, NULL, 0, 1);
+    scheme_set_sync_target(sinfo, v, NULL, NULL, 0, 1, NULL);
     return 0;
   }
 
@@ -1026,12 +1026,12 @@ static int evt_struct_is_ready(Scheme_Object *o, Scheme_Schedule_Info *sinfo)
       if (scheme_is_evt(result)) {
 	SCHEME_USE_FUEL(1); /* Needed beause an apply of a mzc-generated function
 			       might not check for breaks. */
-	scheme_set_sync_target(sinfo, result, NULL, NULL, 0, 1);
+	scheme_set_sync_target(sinfo, result, NULL, NULL, 0, 1, NULL);
 	return 0;
       }
 
       /* non-evt => ready and result is self */
-      scheme_set_sync_target(sinfo, o, o, NULL, 0, 0);
+      scheme_set_sync_target(sinfo, o, o, NULL, 0, 0, NULL);
 
       return 1;
     }
@@ -2129,7 +2129,7 @@ static int wrapped_evt_is_ready(Scheme_Object *o, Scheme_Schedule_Info *sinfo)
     wrapper = scheme_box(ww->wrapper);
   }
 
-  scheme_set_sync_target(sinfo, ww->evt, wrapper, NULL, 0, 1);
+  scheme_set_sync_target(sinfo, ww->evt, wrapper, NULL, 0, 1, NULL);
   return 0;
 }
 
@@ -2149,7 +2149,7 @@ static int nack_guard_evt_is_ready(Scheme_Object *o, Scheme_Schedule_Info *sinfo
   /* Install the semaphore immediately, so that it's posted on
      exceptions (e.g., breaks) even if they happen while trying
      to run the maker. */
-  scheme_set_sync_target(sinfo, o, NULL, sema, 0, 0);
+  scheme_set_sync_target(sinfo, o, NULL, sema, 0, 0, NULL);
 
   /* Remember both the sema and the current thread's dead evt: */
   nack = scheme_alloc_object();
@@ -2162,7 +2162,7 @@ static int nack_guard_evt_is_ready(Scheme_Object *o, Scheme_Schedule_Info *sinfo
   result = scheme_apply(nw->maker, 1, a);
 
   if (scheme_is_evt(result)) {
-    scheme_set_sync_target(sinfo, result, NULL, NULL, 0, 1);
+    scheme_set_sync_target(sinfo, result, NULL, NULL, 0, 1, NULL);
     return 0;
   } else
     return 1; /* Non-evt => ready */
@@ -2182,7 +2182,7 @@ static int nack_evt_is_ready(Scheme_Object *o, Scheme_Schedule_Info *sinfo)
   }
 
   /* Redirect to the set, and wrap with void: */
-  scheme_set_sync_target(sinfo, wset, scheme_void, NULL, 0, 1);
+  scheme_set_sync_target(sinfo, wset, scheme_void, NULL, 0, 1, NULL);
 
   return 0;
 }
@@ -2201,7 +2201,7 @@ static int poll_evt_is_ready(Scheme_Object *o, Scheme_Schedule_Info *sinfo)
   result = scheme_apply(nw->maker, 1, a);
 
   if (scheme_is_evt(result)) {
-    scheme_set_sync_target(sinfo, result, NULL, NULL, 0, 1);
+    scheme_set_sync_target(sinfo, result, NULL, NULL, 0, 1, NULL);
     return 0;
   } else
     return 1; /* Non-evt => ready */
diff --git a/src/mzscheme/src/thread.c b/src/mzscheme/src/thread.c
index 1d0d529824..59a702b9a4 100644
--- a/src/mzscheme/src/thread.c
+++ b/src/mzscheme/src/thread.c
@@ -2937,7 +2937,7 @@ static int thread_wait_done(Scheme_Object *p, Scheme_Schedule_Info *sinfo)
        the blocking thread can be dequeued: */
     Scheme_Object *evt;
     evt = scheme_get_thread_dead((Scheme_Thread *)p);
-    scheme_set_sync_target(sinfo, evt, p, NULL, 0, 0);
+    scheme_set_sync_target(sinfo, evt, p, NULL, 0, 0, NULL);
     return 0;
   } else
     return 1;
@@ -4978,11 +4978,11 @@ static int resume_suspend_ready(Scheme_Object *o, Scheme_Schedule_Info *sinfo)
 
   t = SCHEME_PTR2_VAL(o);
   if (t) {
-    scheme_set_sync_target(sinfo, o, t, NULL, 0, 0);
+    scheme_set_sync_target(sinfo, o, t, NULL, 0, 0, NULL);
     return 1;
   }
 
-  scheme_set_sync_target(sinfo, SCHEME_PTR1_VAL(o), o, NULL, 0, 1);
+  scheme_set_sync_target(sinfo, SCHEME_PTR1_VAL(o), o, NULL, 0, 1, NULL);
   return 0;
 }
 
@@ -5015,7 +5015,7 @@ Scheme_Object *scheme_get_thread_dead(Scheme_Thread *p)
 
 static int dead_ready(Scheme_Object *o, Scheme_Schedule_Info *sinfo)
 {
-  scheme_set_sync_target(sinfo, SCHEME_PTR_VAL(o), o, NULL, 0, 1);
+  scheme_set_sync_target(sinfo, SCHEME_PTR_VAL(o), o, NULL, 0, 1, NULL);
   return 0;
 }
 
@@ -5163,7 +5163,7 @@ static void *splice_ptr_array(void **a, int al, void **b, int bl, int i)
 
 static void set_sync_target(Syncing *syncing, int i, Scheme_Object *target, 
 			    Scheme_Object *wrap, Scheme_Object *nack, 
-			    int repost, int retry)
+			    int repost, int retry, Scheme_Accept_Sync accept)
 /* Not ready, deferred to target. */
 {
   Evt_Set *evt_set = syncing->set;
@@ -5202,6 +5202,16 @@ static void set_sync_target(Syncing *syncing, int i, Scheme_Object *target,
     syncing->reposts[i] = 1;
   }
 
+  if (accept) {
+    if (!syncing->accepts) {
+      Scheme_Accept_Sync *s;
+      s = (Scheme_Accept_Sync *)scheme_malloc_atomic(sizeof(Scheme_Accept_Sync) * evt_set->argc);
+      memset(s, 0, evt_set->argc * sizeof(Scheme_Accept_Sync));
+      syncing->accepts = s;
+    }
+    syncing->accepts[i] = accept;
+  }
+
   if (SCHEME_EVTSETP(target) && retry) {
     /* Flatten the set into this one */
     Evt_Set *wts = (Evt_Set *)target;
@@ -5257,6 +5267,19 @@ static void set_sync_target(Syncing *syncing, int i, Scheme_Object *target,
 	memcpy(s + i + wts->argc, syncing->reposts + i + 1, evt_set->argc - i - 1);
 	syncing->reposts = s;
       }
+      if (syncing->accepts) {
+	Scheme_Accept_Sync *s;
+	int len;
+	
+	len = evt_set->argc + wts->argc - 1;
+	
+	s = (Scheme_Accept_Sync *)scheme_malloc_atomic(len * sizeof(Scheme_Accept_Sync));
+	memset(s, 0, len * sizeof(Scheme_Accept_Sync));
+	
+	memcpy(s, syncing->accepts, i * sizeof(Scheme_Accept_Sync));
+	memcpy(s + i + wts->argc, syncing->accepts + i + 1, (evt_set->argc - i - 1) * sizeof(Scheme_Accept_Sync));
+	syncing->accepts = s;
+      }
 
       evt_set->argc += (wts->argc - 1);
 
@@ -5280,10 +5303,10 @@ static void set_sync_target(Syncing *syncing, int i, Scheme_Object *target,
 
 void scheme_set_sync_target(Scheme_Schedule_Info *sinfo, Scheme_Object *target, 
 			    Scheme_Object *wrap, Scheme_Object *nack, 
-			    int repost, int retry)
+			    int repost, int retry, Scheme_Accept_Sync accept)
 {
   set_sync_target((Syncing *)sinfo->current_syncing, sinfo->w_i,
-		  target, wrap, nack, repost, retry);
+		  target, wrap, nack, repost, retry, accept);
   if (retry) {
     /* Rewind one step to try new ones (or continue
        if the set was empty). */
@@ -5370,6 +5393,8 @@ static int syncing_ready(Scheme_Object *s, Scheme_Schedule_Info *sinfo)
 	    syncing->disable_break->suspend_break++;
 	  if (syncing->reposts && syncing->reposts[i])
 	    scheme_post_sema(o);
+          if (syncing->accepts && syncing->accepts[i])
+            scheme_accept_sync(syncing, i);
 	  scheme_post_syncing_nacks(syncing);
 	  result = 1;
 	  goto set_sleep_end_and_return;
@@ -5387,7 +5412,7 @@ static int syncing_ready(Scheme_Object *s, Scheme_Schedule_Info *sinfo)
       Scheme_Object *sema;
       
       sema = get_sema(o, &repost);
-      set_sync_target(syncing, i, sema, o, NULL, repost, 1);
+      set_sync_target(syncing, i, sema, o, NULL, repost, 1, NULL);
       j--; /* try again with this sema */
     }
   }
@@ -5425,6 +5450,25 @@ static int syncing_ready(Scheme_Object *s, Scheme_Schedule_Info *sinfo)
   return result;
 }
 
+void scheme_accept_sync(Syncing *syncing, int i)
+{
+  /* run atomic accept action to revise the wrap */
+  Scheme_Accept_Sync accept;
+  Scheme_Object *v, *pr;
+  
+  accept = syncing->accepts[i];
+  syncing->accepts[i] = NULL;
+  pr = syncing->wrapss[i];
+  
+  v = SCHEME_CAR(pr);
+  pr = SCHEME_CDR(pr);
+  
+  v = accept(v);
+  
+  pr = scheme_make_pair(v, pr);
+  syncing->wrapss[i] = pr;
+}
+
 static void syncing_needs_wakeup(Scheme_Object *s, void *fds)
 {
   int i;