iifun
(hw_ifun_t)iifun, (void *)slot);
static int iifun(int, int);
add_sicallback((si_farg)iifun, (void*)slot, 0);
static int iifun(int, int);
add_sicallback((si_farg)iifun, (void*)slot, 0);
(hw_ifun_t)iifun, (void *)slot);