Re: signal handling different in 1.8.3 than 1.8.1?

[ludo@gnu.org (Ludovic Courtès)]

Hi,

Gregory Marton <gremio@csail.mit.edu> writes:

> Now that I've upgraded to 1.8.3 from 1.8.1, some old test cases are
> failing.  In particular:

According to `NEWS', there were no signal-related changes.

> (define (ensure body-lambda ensuring-lambda)
>    (dynamic-wind
>        (lambda () #t)
>        body-lambda
>        ensuring-lambda))
>
> (define (with-sigaction signum handler flags lamb)
>      (let ((old-sigaction (sigaction signum)))
>        (if flags (sigaction signum handler flags) (sigaction signum handler))
>        (ensure
>         lamb
>         (lambda ()
>           (sigaction signum (car old-sigaction) (cdr old-sigaction))))))

Signal handlers are invoked asynchronously as system asyncs, and system
asyncs are run whenever `SCM_TICK' is encountered in the C code.

There doesn't seem to be any Scheme procedure to force the execution of
system asyncs, but maybe you can try invoking LAMB above in
`call-with-unblocked-asyncs' and/or adding a `(sleep 0)' right before it
to force the execution of pending system asyncs.

Let us know if it helps.

Thanks,
Ludovic.