diff --git a/src/mfm.hpp b/src/mfm.hpp
index 9ea89b5d..01f3fdb2 100644
--- a/src/mfm.hpp
+++ b/src/mfm.hpp
@@ -1,7 +1,11 @@
 #pragma once
 
+#include "mfm_options.hpp"
+
 namespace mfm
 {
   int main(int    argc,
            char **argv);
+
+  void dup(Opts::Dup &dup);
 }