diff -ur sched.c sched.c
--- sched.c	Wed Jan 30 19:46:11 2002
+++ sched.c	Fri Jan 21 15:14:24 2005
@@ -232,6 +232,21 @@
   return 0;
 }
 
+st_switch_cb_t st_set_switch_in_cb(st_switch_cb_t cb)
+{
+  st_switch_cb_t ocb = _st_this_vp.switch_in_cb;
+
+  _st_this_vp.switch_in_cb = cb;
+  return (ocb);
+}
+
+st_switch_cb_t st_set_switch_out_cb(st_switch_cb_t cb)
+{
+  st_switch_cb_t ocb = _st_this_vp.switch_out_cb;
+
+  _st_this_vp.switch_out_cb = cb;
+  return (ocb);
+}
 
 /*
  * Start function for the idle thread