> To establish a generic softintr there is a function
> 
> void *softintr_establish(int level, int (*fun)(void *), void *arg)
> 
> What is the purpose of the int returned by the `fun'?

Hmm.  Perhaps symmetry with hardware interrupt handlers which return int?

> As far as I can see the return value from calling the handler
> is always thrown away.  So using void would make more sense.

actually, the current implementation of softintr_* has the handler
return void (at variance with the section 9 man page).

				- Bill