How does libev invoke an io watcher if both EV_READ and EV_WRITE are pending?

[Cheyi Lin]

If both EV_READ and EV_WRITE are pending, libev will ...

1) invoke the callback twice, one is for EV_READ, the other is for EV_WRITE.
2) invoke the callback once, revents |= (EV_READ | EV_WRITE).

Which is correct? Thanks.

Regards,
Cheyi Lin