diff --git a/lib/decode_mac.cc b/lib/decode_mac.cc
index 4a22881..d90ad24 100644
--- a/lib/decode_mac.cc
+++ b/lib/decode_mac.cc
@@ -21,6 +21,7 @@
 
 #include <gnuradio/io_signature.h>
 #include <boost/crc.hpp>
+#include <iomanip>
 
 using namespace gr::ieee802_11;