On Tue, Jan 20 2015, Fam Zheng <famz@redhat.com> wrote:

> DESCRIPTION
>
>        The epoll_mod_wait() system call can be seen as an enhanced combination
>        of several epoll_ctl(2) calls, which are followed by an epoll_pwait(2)
>        call. It is superior in two cases:
> 
>        1) When epoll_ctl(2) are followed by epoll_wait(2), using epoll_mod_wait
>        will save context switches between user mode and kernel mode;
> 
>        2) When you need higher precision than microsecond for wait timeout.

You probably want to say millisecond.

>            struct epoll_mod_cmd {
[...]
>            };


>            struct epoll_wait_spec {
[...]
>            } EPOLL_PACKED;

Either both or none of these should mention that EPOLL_PACKED is in fact
part of the actual definition. The changelog for 3/6 sorta mentions
that it's not really needed for epoll_mod_cmd. Why is it necessary for
either struct?

> RETURN VALUE
>
>        When successful, epoll_mod_wait() returns the number of file
>        descriptors ready for the requested I/O, or zero if no file descriptor
>        became ready during the requested timeout milliseconds.

And here, it doesn't make sense to mention a unit, since the new timeout
is given using struct timespec (this was the whole point, right?).

Rasmus