It's really a lower level protocol issue. The serial terminals upon which the "tty" model is based had no event stream outside of characters being sent or recei

It's really a lower level protocol issue. The serial terminals upon which the "tty" model is based had no event stream outside of characters being sent or received. There are events provided by the serial port itself and delivered out-of-band though (example: modem DCD line drops, SIGHUP is generated.)