diff --git a/libofa/examples/protocol.h b/libofa/examples/protocol.h
index 304c9e1..4ed84e2 100644
--- a/libofa/examples/protocol.h
+++ b/libofa/examples/protocol.h
@@ -9,6 +9,7 @@
 #ifndef __PROTOCOL_H__
 #define __PROTOCOL_H__
 
+#include <unistd.h>
 #include <string>
 #include "ofa1/ofa.h"