diff --git a/src/devices/wifi/adhoc-wifi-mac.h b/src/devices/wifi/adhoc-wifi-mac.h
index 7535ca2b0..5805ae709 100644
--- a/src/devices/wifi/adhoc-wifi-mac.h
+++ b/src/devices/wifi/adhoc-wifi-mac.h
@@ -85,6 +85,7 @@ private:
   /* invoked by the MacLows. */
   void ForwardUp (Ptr<Packet> packet, WifiMacHeader const*hdr);
   AdhocWifiMac (const AdhocWifiMac & ctor_arg);
+  AdhocWifiMac &operator = (const AdhocWifiMac &o);
   Mac48Address GetBssid (void) const;
 
   Ptr<DcaTxop> m_dca;
diff --git a/src/devices/wifi/nqap-wifi-mac.h b/src/devices/wifi/nqap-wifi-mac.h
index 48b9a2e7d..5b1948255 100644
--- a/src/devices/wifi/nqap-wifi-mac.h
+++ b/src/devices/wifi/nqap-wifi-mac.h
@@ -112,6 +112,7 @@ private:
   bool GetBeaconGeneration (void) const;
   virtual void DoDispose (void);
   NqapWifiMac (const NqapWifiMac & ctor_arg);
+  NqapWifiMac &operator = (const NqapWifiMac &o);
 
   Ptr<DcaTxop> m_dca;
   Ptr<DcaTxop> m_beaconDca;
diff --git a/src/devices/wifi/nqsta-wifi-mac.h b/src/devices/wifi/nqsta-wifi-mac.h
index 4ca01e84f..16e2064c4 100644
--- a/src/devices/wifi/nqsta-wifi-mac.h
+++ b/src/devices/wifi/nqsta-wifi-mac.h
@@ -129,6 +129,7 @@ private:
   Mac48Address GetBssid (void) const;
   virtual void DoDispose (void);
   NqstaWifiMac (const NqstaWifiMac & ctor_arg);
+  NqstaWifiMac &operator = (const NqstaWifiMac & ctor_arg);
 
   enum {
     ASSOCIATED,