Re: [bug?] curses + threads = non-blocking getch

In article <[e-mail]>,
  William Morgan <[e-mail]> writes:

> Using the curses library, it looks like non-blocking getch (i.e. when
> Ncurses.nodelay = 1) will block when there are other Threads running.
> Once the other Thread dies, it resumes non-blocking operation, but only
> once a key is pressed. With the ncurses library, this problem doesn't
> happen.

It is not a non-blocking I/O.  It checks an available input before
reading.  It can be re-implemented as follows:

  require "curses"

  class Curses::Window
    def getch_nodelay
      if IO.select([STDIN], nil, nil, 0)
        getch
      else
        -1
      end
    end
  end

  begin
    Curses.init_screen
    Curses.noecho

    start = Time.now
    Thread.new { sleep 5; }

    while true
      Curses.stdscr.setpos(5, 5)
      Curses.stdscr.addstr("#{(Time.now - start).round} waiting for input...")
      Curses.refresh

      x = Curses.stdscr.getch_nodelay

      Curses.stdscr.setpos(5, 5)
      Curses.stdscr.addstr("#{(Time.now - start).round} got: #{x}             ")
      Curses.refresh

      sleep 0.5
    end
  ensure
    Curses.echo
    Curses.close_screen
  end
-- 
Tanaka Akira