added channel destroy notify mf

src/db/dbSubscriptionIO.cpp

@@ -23,6 +23,7 @@
 
 #include "cacIO.h"
 #include "db_access.h" // need to eliminate this
+#include "cadef.h" // this can be eliminated when the callbacks use the new interface
 
 #define epicsExportSharedSymbols
 #include "dbCAC.h"
@@ -76,6 +77,12 @@ extern "C" void dbSubscriptionEventCallback ( void *pPrivate, struct dbAddr * /*
     pIO->chan.callStateNotify ( pIO->type, pIO->count, pfl, pIO->notify );
 }
 
+void dbSubscriptionIO::channelDestroyNotify ()
+{
+    this->notify.exception ( ECA_CHANDESTROY,
+        this->chan.pName(), this->type, this->count );
+}
+
 void dbSubscriptionIO::show ( unsigned level ) const
 {
     printf ( "Data base subscription IO at %p\n",