diff --git a/src/ca/udpiiu.cpp b/src/ca/udpiiu.cpp
index 2e5560a3b..17dc43282 100644
--- a/src/ca/udpiiu.cpp
+++ b/src/ca/udpiiu.cpp
@@ -290,6 +290,10 @@ bool udpRecvThread::exitWait ( double delay )
     return this->thread.exitWait ( delay );
 }
 
+void udpRecvThread::show ( unsigned /* level */ ) const
+{
+}
+
 void udpRecvThread::run ()
 {
     epicsThreadPrivateSet ( caClientCallbackThreadId, &this->iiu );
diff --git a/src/ca/udpiiu.h b/src/ca/udpiiu.h
index 8daedd6c6..86373c1d8 100644
--- a/src/ca/udpiiu.h
+++ b/src/ca/udpiiu.h
@@ -57,7 +57,7 @@ class cac;
 class cacContextNotify;
 
 class udpRecvThread : 
-        public epicsThreadRunable {
+        private epicsThreadRunable {
 public:
     udpRecvThread ( 
         class udpiiu & iiuIn, cacContextNotify &, epicsMutex &,
@@ -65,6 +65,7 @@ public:
     virtual ~udpRecvThread ();
     void start ();
     bool exitWait ( double delay );
+    void show ( unsigned level ) const;
 private:
     class udpiiu & iiu;
     epicsMutex & cbMutex;
@@ -180,7 +181,7 @@ private:
         epicsGuard < epicsMutex > &, const caHdr &msg, 
         const osiSockAddr &net_addr, const epicsTime & );
 
-    friend void udpRecvThread::run ();
+    friend class udpRecvThread;
 
     void hostName ( 
         epicsGuard < epicsMutex > &,