Connects a signal to the given callback. The callback will be called only after all "normal" (i.e. not-after) callbacks have been activated. For the exact callback parameters see the docs of the respective signal in the class documentation.
The method returns a signal handler id that can be used to block() or disconnect() the handler.
For more information about signals, see the Signal Handling tutorial
See also: connect() , connect_simple() , connect_simple_after() ,