Code review comment for lp:~robertcarr/mir/client-focus-notifications

> just curious...is this some convention ?
> mir_surface_focus_arraysize_
> didn't understand why it was in the surf attrib for focusstate

Yes, it is a sentinel element for the array, and its value is equal to the array size.

> in general...might be my lack of understanding. there are some mutex/surface
> locks in the proposed code....but i don't see unlocks (do those happen
> automagically as the code goes out of scope?)

std::unique_lock<> and std::lock_guard<> are scoped locks. They lock the associated mutex when created, and unlock it when going out of scope.