PC-lint: Silence warning about virtual destructor

diff --git a/asyncio/async_io.hpp b/asyncio/async_io.hpp
index 3c2f62a..8291543 100644 (file)
--- a/asyncio/async_io.hpp
+++ b/asyncio/async_io.hpp
@@ -220,7 +220,7 @@ class IOImplementation
 
     public:
         IOImplementation(int read_fd=-1, int write_fd=-1);
-        virtual ~IOImplementation();
+        virtual ~IOImplementation();                //lint !e1509  // boost::signals::trackable is not virtual
 
         virtual void close(Direction direction = Direction::both);