diff --git a/vpnor/test/write_rw.cpp b/vpnor/test/write_rw.cpp
index 7760fc7..76b1525 100644
--- a/vpnor/test/write_rw.cpp
+++ b/vpnor/test/write_rw.cpp
@@ -10,7 +10,9 @@
 
 #include "common.h"
 #include "mbox.h"
+extern "C" {
 #include "flash.h"
+}
 
 #include "vpnor/test/tmpd.hpp"