From: Pit Capitain <pit@...>
Date: 2007-03-16T22:59:33+09:00
Subject: Re: Trapping ESC key

RubyCrazy schrieb:
> Harry, I have tried HighLine but that's not what I want (or am I making a
> mistake here?). I am trying to solve the problem - ** "Display series of
> numbers (1,2,3,4, 5�.etc) in an infinite loop. The program should quit if
> someone hits a specific key (Say ESCAPE key)."
> 
> Somehow I want to keep checking in a thread (this should be non-blocking)
> for the ESC key press. Once ESC is pressed my program terminates. Right 
> now,
> my thread code blocks till I press ESC key, as you can see here -
> 
> require 'Win32API'
> def getchar
>  char = Win32API.new("crtdll", "_getch", [], 'L').call
>  if char == 27 # ESC key
>    exit
>  end
> end
> 
> i = 0
> loop do
>  print "#{i+=1}, "
>  getchar
> end
> 
> What should I do? Thanks.

Change your operating system, or don't use threads with blocking 
keyboard I/O. It doesn't work on Windows. For your code above (which 
doesn't use threads) you could call the Win32 function "_kbhit" before 
calling "_getch". In a thread you could do the same in a busy loop, but 
don't forget to sleep a little bit inside the loop.

Regards,
Pit