Interrupt handlers are not called

I'm trying to use the interrupts package's set-interrupt-handler! to
catch interrupts of type os-signal. The handler I set seems to never
be called though. If i send a sigchld to the scheme48 process, nothing
happens, and if i send something more exotic like sigpwr on linux, it
actually dies.

Interrupt handlers seem to work as expected in the scheme48 bundled
with scsh 0.6.7 (or else they changed it to work). It may be the case
that the package's usage has changed, but there doesn't seem to be any
documentation for it, so I can't tell. Should something like this
work?

(set-interrupt-handler! (enum interrupt os-signal)
                        (lambda (type enabled-interrupts)
                          (display type) (newline)
                          (display enabled-interrupts) (newline)))

-Roderic