diff --git a/event.c b/event.c
index d3394b1d..0e711c81 100644
--- a/event.c
+++ b/event.c
@@ -134,7 +134,7 @@ static void	event_queue_insert(struct event_base *, struct event *, int);
 static void	event_queue_remove(struct event_base *, struct event *, int);
 static int	event_haveevents(struct event_base *);
 
-static void	event_process_active(struct event_base *);
+static int	event_process_active(struct event_base *);
 
 static int	timeout_next(struct event_base *, struct timeval **);
 static void	timeout_process(struct event_base *);
@@ -1341,19 +1341,19 @@ event_process_deferred_callbacks(struct deferred_cb_queue *queue, int *breakptr)
  * priority ones.
  */
 
-static void
+static int
 event_process_active(struct event_base *base)
 {
 	/* Caller must hold th_base_lock */
 	struct event_list *activeq = NULL;
-	int i, c;
+	int i, c = 0;
 
 	for (i = 0; i < base->nactivequeues; ++i) {
 		if (TAILQ_FIRST(&base->activequeues[i]) != NULL) {
 			activeq = &base->activequeues[i];
 			c = event_process_active_single_queue(base, activeq);
 			if (c < 0)
-				return;
+				return -1;
 			else if (c > 0)
 				break; /* Processed a real event; do not
 					* consider lower-priority events */
@@ -1363,6 +1363,7 @@ event_process_active(struct event_base *base)
 	}
 
 	event_process_deferred_callbacks(&base->defer_queue,&base->event_break);
+	return c;
 }
 
 /*
@@ -1547,8 +1548,10 @@ event_base_loop(struct event_base *base, int flags)
 		timeout_process(base);
 
 		if (N_ACTIVE_CALLBACKS(base)) {
-			event_process_active(base);
-			if (!base->event_count_active && (flags & EVLOOP_ONCE))
+			int n = event_process_active(base);
+			if ((flags & EVLOOP_ONCE)
+			    && N_ACTIVE_CALLBACKS(base) == 0
+			    && n != 0)
 				done = 1;
 		} else if (flags & EVLOOP_NONBLOCK)
 			done = 1;
diff --git a/include/event2/event.h b/include/event2/event.h
index 8978545b..ba21d221 100644
--- a/include/event2/event.h
+++ b/include/event2/event.h
@@ -324,8 +324,12 @@ int event_base_set(struct event_base *, struct event *);
  event_loop() flags
  */
 /*@{*/
-#define EVLOOP_ONCE	0x01	/**< Block at most once. */
-#define EVLOOP_NONBLOCK	0x02	/**< Do not block. */
+/** Block until we have an active event, then exit once all active events
+ * have had their callbacks run. */
+#define EVLOOP_ONCE	0x01
+/** Do not block: see which events are ready now, run the callbacks
+ * highest-priority ones, then exit. */
+#define EVLOOP_NONBLOCK	0x02
 /*@}*/
 
 /**