Return values in Wayland XML specification

[adlo]

> On 26 Apr 2017, at 08:23, Pekka Paalanen <ppaalanen at gmail.com> wrote:
> 
> If you need a client to receive something as a reply to a request, you
> need to specify an event for delivering it. There are no shortcuts for
> that, because each roundtrip makes everything a tiny bit slower, and
> that accumulates. Therefore one should reconsider if a roundtrip is
> really necessary, or if things could be designed to be asynchronous
> instead.

For example, getting a list of windows and returning it as an array. How would this be done? How are arrays represented in Wayland XML?

Regards

adlo