extern void io_del(io_t *io);
extern void io_set(io_t *io, int flags);
-extern void timeout_add(timeout_t *timeout, timeout_cb_t cb, void *data, struct timeval *tv);
+extern void timeout_add(timeout_t *timeout, timeout_cb_t cb, void *data, const struct timeval *tv);
extern void timeout_del(timeout_t *timeout);
-extern void timeout_set(timeout_t *timeout, struct timeval *tv);
+extern void timeout_set(timeout_t *timeout, const struct timeval *tv);
extern void signal_add(signal_t *sig, signal_cb_t cb, void *data, int signum);
extern void signal_del(signal_t *sig);