Otherwise, any previously installed handler is uninstalled, and future occurrences of the event will cause an error (32).
Success: [eclipse 1]: event(hello). warning: no handler for event in hello yes. [eclipse 2]: set_event_handler(hello, writeln/1). yes. [eclipse 3]: event(hello). hello [eclipse 2]: reset_event_handler(hello). yes. [eclipse 3]: event(hello). warning: no handler for event in hello yes.