add callback API for detecting connection/removal of devices

[rossb]

Add an API to allow clients to be notified (or to poll) for whether audio devices have been connected or disconnected.

[rossb]

Robert Bielik adds: As it is now, the available audio devices are discovered during Pa_Initialize(). I'd like to have it possible to check if any new devices have been added (such as a headset), while still playing a stream with connected devices. Would that be possible?

[rossb]

Erik Bunce submitted a patch for this in October 2007: http://techweb.rfa.org/pipermail/portaudio/2007-October/007719.html

There were a number of issues raised, see discussion in October: http://techweb.rfa.org/pipermail/portaudio/2007-October/thread.html#7719 and November: http://techweb.rfa.org/pipermail/portaudio/2007-November/

All under the subject "Plug-and-play patch for portaudio"

From memory one of the issues was concerned with dealing with concurrency issues.

This issue needs to revisited and a decision reached.

[rossb]

Eric Bunce's Plug-and-play patch for portaudio, see http://techweb.rfa.org/pipermail/portaudio/2007-October/007719.html