diff --git a/IOStreams/StreamState.h b/IOStreams/StreamState.h
index f9d247a..b3263a4 100644
--- a/IOStreams/StreamState.h
+++ b/IOStreams/StreamState.h
@@ -4,6 +4,9 @@ static_assert( __cplusplus > 2020'99 );
 
 #include <ios>
 #include <exception>
+#include <functional>
+
+#include <boost/noncopyable.hpp>
 
 #include <Alepha/Alepha.h>