Missing hotplug support

[GitHub issues - opened]

alsa-project/alsa-lib issue #55 was opened from wm4:

Hotplug support is mandatory in any modern system. But in ALSA there is no way to be notified by audio device changes.

I'm aware that as a hack, one could listen to udev notifications. But this is not appropriate, because:
- udev is a different API, which makes this is inelegant and messy
- it requires a dependency on udev, which may not be a workable solution even if the host OS is Linux
- there may be devices that do not have anything to do with udev (for example network audio interfaces implemented in userspace)
- changes in udev may not be reflected in ALSA at the same time (creating the need to avoid race conditions with timeouts or whatever)
- it's ALSA's responsibility to provide this; I don't know any OS where you have to go to a completely different API for this

Issue URL     : https://github.com/alsa-project/alsa-lib/issues/55
Repository URL: https://github.com/alsa-project/alsa-lib