diff --git a/src/cas/generic/casInternal.h b/src/cas/generic/casInternal.h
index aac470955..0d196eb51 100644
--- a/src/cas/generic/casInternal.h
+++ b/src/cas/generic/casInternal.h
@@ -284,7 +284,7 @@ class casChannelI : public tsDLNode<casChannelI>, public casRes,
 				public casEvent {
 public:
 	casChannelI (const casCtx &ctx);
-	virtual ~casChannelI();
+	epicsShareFunc virtual ~casChannelI();
 
 	casCoreClient &getClient () const
 	{