[racket] SIgnal-catching in Racket

I don't know myself, but control-c raises an exception from an
OS-level signal handler and so probably you'll have to make a similar
bridge and that code might be worth looking at.

Robby


On Sat, Dec 20, 2014 at 1:05 PM, Tony Garnock-Jones <tonyg at ccs.neu.edu> wrote:
> Hi all,
>
> If I wanted to catch a Unix signal (say, SIGUSR1) within my Racket
> program, how should I go about it?
>
> My current best guess is:
>  - load a C extension, which
>  - creates a semaphore and
>  - hooks the signal with a handler (MZ_SIGSET looks relevant), which
>  - posts to the semaphore when the signal arrives.
>
> However this seems like a recipe for problems. Is it even permitted to
> post to a semaphore from a signal handler? Will the runtime be upset
> about unscheduled intrusions into its demesne? Is it possible for a C
> extension to allocate a global value like a semaphore and make it
> available to Racket code?
>
> Is there a better way?
>
>  - Perhaps a self-pipe would be better than a semaphore?
>  - A thread from 2006 [1] points at scheme_signal_received() but
>    I don't understand why creating an event type is the right thing
>    to do.
>
> Tony
>
> [1] http://lists.racket-lang.org/users/archive/2006-July/013999.html
>
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