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handling a keyboard interrupt

   Date: Mon, 23 Apr 90 15:59 EDT
   From: Barry Margolin <barmar@Think.COM>

       Date: Mon, 23 Apr 90 11:44:02 PDT
       From: kosma%flow@STC.LOCKHEED.COM (Monty Kosma)

	  From: jwalker@crl.dec.com
	  Date: Fri, 20 Apr 90 17:31:13 EDT

	  I think you want to look at the documentation in the section
	  called Conditions.  You don't want to handle keyboard
	  interrupts; you want to provide your own handler for
	  conditions like sys:abort.  It takes some time staring at
	  examples to figure out this condition stuff but it is
	  cleaner than what I think you are thinking of.

       This is true; however, with lucid 3.0 which I've been using lately, the
       condition stuff does just about everything EXCEPT handle keyboard
       interrupts.  It's too bad they didn't/couldn't hook it into the CL
       condition stuff.  Anyway, I'll do this for the symbolics code.  thanks....

   It should be pretty easy to write your own Lucid interrupt handlers that
   turn keyboard interrupts into conditions as Symbolics does.  The only
   caveat is that the interface from Lucid to Unix signals is undocumented
   and internal:

   (lucid::setup-interrupt-handler <interrupt-number> <handler>)

   <interrupt-number> is a Unix signal number, and <handler> is either
   :IGNORE or a function of two arguments, the signal number and a code
   (which I assume are the same as the parameters passed to a signal
   handler defined by the C function signal()).  Something like this should

   (define-condition abort (condition) ()

   (defun ^C-handler (signal code)
     (declare (ignore signal code))
     (interrupt-process *keyboard-interrupt-process*
			#'(lambda () (signal 'abort))))

   (defconstant SIGINT 2)

   (lucid::setup-interrupt-handler SIGINT #'^C-handler)

   This makes ^C in Lucid equivalent to C-Abort in Genera.  However, you'll
   still have to set up handlers for it.


this is a good idea; this will make most of the code as "CL" as possible...