diff --git a/lib/isc/event.c b/lib/isc/event.c
index 261b4e8789..b1d8b14340 100644
--- a/lib/isc/event.c
+++ b/lib/isc/event.c
@@ -29,6 +29,13 @@
  *** Events.
  ***/
 
+static void
+destroy(isc_event_t *event) {
+	isc_mem_t *mctx = event->destroy_arg;
+
+	isc_mem_put(mctx, event, event->size);
+}
+
 isc_event_t *
 isc_event_allocate(isc_mem_t *mctx, void *sender, isc_eventtype_t type,
 		   isc_taskaction_t action, void *arg, size_t size)
@@ -43,13 +50,14 @@ isc_event_allocate(isc_mem_t *mctx, void *sender, isc_eventtype_t type,
 	event = isc_mem_get(mctx, size);
 	if (event == NULL)
 		return (NULL);
-	event->mctx = mctx;
 	event->size = size;
-	event->sender = sender;
+	event->attributes = 0;
 	event->type = type;
+	event->sender = sender;
 	event->action = action;
 	event->arg = arg;
-	event->destroy = NULL;
+	event->destroy = destroy;
+	event->destroy_arg = mctx;
 	ISC_LINK_INIT(event, link);
 
 	return (event);
@@ -65,7 +73,6 @@ isc_event_free(isc_event_t **eventp) {
 
 	if (event->destroy != NULL)
 		(event->destroy)(event);
-	isc_mem_put(event->mctx, event, event->size);
 
 	*eventp = NULL;
 }
diff --git a/lib/isc/include/isc/event.h b/lib/isc/include/isc/event.h
index cbc13added..53550fb51e 100644
--- a/lib/isc/include/isc/event.h
+++ b/lib/isc/include/isc/event.h
@@ -31,19 +31,34 @@ ISC_LANG_BEGINDECLS
 
 typedef void (*isc_eventdestructor_t)(isc_event_t *);
 
+/*
+ * XXXRTH  These fields may soon be prefixed with something like "ev_"
+ *         so that there's no way someone using ISC_EVENT_COMMON could
+ *         have a namespace conflict with us.
+ *
+ *	   On the other hand, if we ever changed the contents of this
+ *	   structure, we'd break binary compatibility, so maybe this isn't
+ *         really an issue.
+ */
+#define ISC_EVENT_COMMON(ltype)		\
+	size_t				size; \
+	unsigned int			attributes; \
+	isc_eventtype_t			type; \
+	isc_taskaction_t		action; \
+	void *				arg; \
+	void *				sender; \
+	isc_eventdestructor_t		destroy; \
+	void *				destroy_arg; \
+	ISC_LINK(ltype)			link
+
+#define ISC_EVENTATTR_NOPURGE		0x00000001
+
 /*
  * This structure is public because "subclassing" it may be useful when
  * defining new event types.
  */ 
 struct isc_event {
-	isc_mem_t *			mctx;
-	size_t				size;
-	void *				sender;
-	isc_eventtype_t			type;
-	isc_taskaction_t		action;
-	void *				arg;
-	isc_eventdestructor_t		destroy;
-	ISC_LINK(struct isc_event)	link;
+	ISC_EVENT_COMMON(struct isc_event);
 };
 
 #define ISC_EVENTTYPE_FIRSTEVENT	0x00000000