Is there any mechanism in boost::signals that could provide notification when a slot/connection dies (is disconnected)? This functionality is needed to "chain" signals effectively. Imagine wrapping an existing signal-based library with a signal-based interface of some other type: a user connects to some signal on the wrapper, which then connects to some corresponding signal in the inner library. If the user disconnects from the wrapper's signal, the wrapper library would like to disconnect its associated connection to the inner library signal---but it has no way of knowing when the user's connection dies. Am I missing some trick that would give me this functionality? Would a patch implementing this functionality be accepted? Any suggestions for such an interface? -- Bryan Silverthorn <bsilvert@cs.utexas.edu>