iu_eh_sighandler_t
iu_eh_register_signal(iu_eh_t *eh, int sig, iu_eh_sighandler_t *handler,
int iu_eh_register_signal(iu_eh_t *, int, iu_eh_sighandler_t *,
iu_eh_sighandler_t *iues_handler; /* handler for a given signal */