fixed proper shutdown of local CA subscriptions

src/db/dbCAC.h

@@ -72,6 +72,7 @@ public:
     dbSubscriptionIO ( dbServiceIO &, dbChannelIO &, struct dbAddr &, cacStateNotify &, 
         unsigned type, unsigned long count, unsigned mask, cacChannel::ioid * );
     void destroy ();
+    void channelDestroyException ();
     void show ( unsigned level ) const;
     void * operator new ( size_t size );
     void operator delete ( void *pCadaver, size_t size );

src/db/dbServiceIO.cpp

@@ -263,6 +263,9 @@ void dbServiceIO::destroyAllIO ( dbChannelIO & chan )
         }
     }
     while ( ( pIO = tmp.get() ) ) {
+        // If they call ioCancel() here it will be ignored
+        // because the IO has been unregistered above
+        pIO->channelDestroyException ();
         pIO->destroy ();
     }
     if ( chan.dbServicePrivateListOfIO::pBlocker ) {

src/db/dbSubscriptionIO.cpp

@@ -57,8 +57,6 @@ dbSubscriptionIO::~dbSubscriptionIO ()
     if ( this->es ) {
         db_cancel_event ( this->es );
     }
-    this->notify.exception ( ECA_CHANDESTROY,
-        this->chan.pName(), this->type, this->count );
 }
 
 void dbSubscriptionIO::destroy ()
@@ -66,6 +64,12 @@ void dbSubscriptionIO::destroy ()
     delete this;
 }
 
+void dbSubscriptionIO::channelDestroyException ()
+{
+    this->notify.exception ( ECA_CHANDESTROY, 
+        this->chan.pName(), this->type, this->count );
+}
+
 void * dbSubscriptionIO::operator new ( size_t size )
 {
     epicsAutoMutex locker ( dbSubscriptionIO::freeListMutex );