• The connection is explicitly disconnected via the connection's disconnect method directly, or indirectly via the signal's disconnect method or scoped_connection's destructor.

• A trackable object bound to the slot is destroyed.

• The signal is destroyed.

Is anyone aware of other conditions under which a connection could become NULL ?

Here is a code snippet:

-----------------------------------------------------------------
boost::signal<int(vtkLookupTable*)> m_signal;
boost::signals::connection m_connection;
....
CScalarBarLayerGeometry* l_receive = cast_poly<CScalarBarLayerGeometry*>(p_layer->GetGeometry())
m_connection =  m_signal.connect(boost::bind(&CScalarBarLayerGeometry::SetLookupTable,l_receive, _1));
-------------------------------------------------------------------

The first time I invoke m_connection.connected()
it returns true. The second time it returns false and the connection is NULL.

Any help would be appreciated.
Best regards, Oliver