Does this help? This may be related to the cooked/uncooked/rare <http://en.wikipedia.org/wiki/POSIX_terminal_interface#Early_Unices%3a_Seventh_Edition_Unix> terminal modes; ^C does not always send a signal. It seems likely that readline uncooks the terminal, and thus any signals caused by keyboard input must be due to logic within readline itself; it seems plausible that it might only trigger a SIGINT on two sequential ^Cs (especially since for many programs that utilise readline such as shells and REPLs, the program exiting on a single ^C would be very annoying!).
You might be able to change this behaviour by using the readline API to rebind ^C to some of your own code that triggers a SIGINT. I haven't used readline from Haskell, just from C, so I'm not sure exactly how you'd go about this, but the binding <http://hackage.haskell.org/packages/archive/readline/latest/doc/html/System-Console-Readline.html> seems rich enough to achieve it. On Mon, Jul 21, 2014 at 12:39 PM, Juergen Sauermann < juergen.sauerm...@t-online.de> wrote: > Hi David, > > I see. The problem is that the line input (readline) does not return even > though I tell it to (by setting *rl_done* in the signal handler for ^C). > I haven't > found a way to fix this (hints more than welcome). This could also be > caused > by terminal settings ("cooked mode") but I thought readline would handle > this. > > Long term I will most likely replace readline because so far it has > created more problems > than it has helped. That would be a bigger issue and should also be > aligned with Elias' > emacs mode. So it would be after the next GNU APL release. > > /// Jürgen > > > > On 07/21/2014 06:32 PM, David B. Lamkins wrote: > > Thanks, Jüergen. > > The real issue, from my perspective, is that APL doesn't report the > ATTENTION message until it sees a newline on input. It seems to me that > typing a ^C should immediately suspend execution and show the ATTENTION > message. > > On Mon, 2014-07-21 at 18:23 +0200, Juergen Sauermann wrote: > > Hi David, > > I have changed readline to display a new line right after ^C, see SVN 382. > > For reasons that I don't fully understand, the next character after ^C > will be eaten by > readline; I tried a number of things to prevent this but haven't succeeded. > > I believe readline will be one of the next things removed from GNU APL. > > /// Jürgen > > > On 07/21/2014 02:32 AM, David Lamkins wrote: > > When the session is not executing APL code, the attention signal is > not handled until the next newline. > > To see this, enter the characters Control-C, 1, Return. > > > -- > "The secret to creativity is knowing how to hide your sources." > Albert Einstein > > http://soundcloud.com/davidlamkinshttp://reverbnation.com/lamkinshttp://reverbnation.com/lcwhttp://lamkins-guitar.com/http://lamkins.net/http://successful-lisp.com/ > > >
