added shutdown () sys call diagnostics

src/ca/tcpiiu.cpp

@@ -506,8 +506,14 @@ void tcpiiu::shutdown ()
 {
     LOCK ( this->pcas );
     if ( this->state != iiu_disconnected ) {
+        int status;
+
         this->state = iiu_disconnected;
-        ::shutdown ( this->sock, SD_BOTH );
+        status = ::shutdown ( this->sock, SD_BOTH );
+        if ( status ) {
+            errlogPrintf ("CAC TCP shutdown error was %s\n", 
+                SOCKERRSTR (SOCKERRNO) );
+        }
         cacRingBufferShutDown ( &this->send );
         cacRingBufferShutDown ( &this->recv );
         this->pcas->signalRecvActivityIIU ( *this );

src/ca/udpiiu.cpp

@@ -585,7 +585,14 @@ udpiiu::~udpiiu ()
  */
 void udpiiu::shutdown ()
 {
-    ::shutdown (this->sock, SD_BOTH);
+    int status;
+
+    status = ::shutdown (this->sock, SD_BOTH);
+    if ( status ) {
+        errlogPrintf ( "CAC UDP shutdown error was %s\n", 
+            SOCKERRSTR (SOCKERRNO) );
+    }
+
     this->shutdownCmd = true;
     semBinaryGive (this->xmitSignal);
 }