JOE never tries to use poll or select (it uses multiple sub-processes writing to the same pipe to implement input multiplexing). This archaic way works on all

JOE never tries to use poll or select (it uses multiple sub-processes writing to the same pipe to implement input multiplexing). This archaic way works on all version of UNIX, even very old ones which don't have select() or poll(). No #ifdefs needed :-) Output processing in JOE is interesting: when writing to the terminal, JOE periodically sleeps for a time based on the baud rate and amount of data. This is to prevent too much output buffering so that at low baud rates you can interrupt the screen refresh with type-ahead. If you don't do this at 1200 baud it's a big issue (you could wait for hours if you hit PageDown too many times).