X-Git-Url: https://main.carlh.net/gitweb/?a=blobdiff_plain;f=src%2Flib%2Fevent_history.h;h=4670e7bfe8069b215448d09c62f545af909c7d1c;hb=4787f3a114115a16f7007c7b1bd36fb2e2121345;hp=f723591fbd19bd81c0fa052e997a59c88195a22c;hpb=b19987ae5342602977b265ba9167ec09e433367c;p=dcpomatic.git

diff --git a/src/lib/event_history.h b/src/lib/event_history.h
index f723591fb..4670e7bfe 100644
--- a/src/lib/event_history.h
+++ b/src/lib/event_history.h
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2017 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2017-2019 Carl Hetherington <cth@carlh.net>
 
     This file is part of DCP-o-matic.
 
@@ -22,14 +22,15 @@
 #define DCPOMATIC_EVENT_HISTORY_H
 
 #include <boost/thread/mutex.hpp>
+#include <boost/optional.hpp>
 #include <list>
 
 class EventHistory
 {
 public:
-	EventHistory (int size);
+	explicit EventHistory (int size);
 
-	float rate () const;
+	boost::optional<float> rate () const;
 	void event ();
 
 private: