X-Git-Url: https://git.carlh.net/gitweb/?a=blobdiff_plain;f=src%2Flib%2Fevent_history.h;h=a98447f4246f58aa37d11514a59406e59a3af326;hb=ff639b3cf30afcc097bfd21d39c8d15f466cadd6;hp=5b0f9a6a3879a876810cacb772a1aa1d08761405;hpb=6a11232620e0006f6a2b1e8d2b56e56d84229d5c;p=dcpomatic.git

diff --git a/src/lib/event_history.h b/src/lib/event_history.h
index 5b0f9a6a3..a98447f42 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) 2017-2021 Carl Hetherington <cth@carlh.net>
 
     This file is part of DCP-o-matic.
 
@@ -18,15 +18,22 @@
 
 */
 
+
+#ifndef DCPOMATIC_EVENT_HISTORY_H
+#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:
@@ -39,3 +46,6 @@ private:
 	/** Number of events that we should keep history for */
 	int const _size;
 };
+
+
+#endif