Rob Watson writes:
> In CoreAudio, if a device which is being read from is suddenly removed/unplugged, then PortAudio repeatedly loops while printing an error:
>
> Error on line 2134: err='-10863', msg=Audio Unit: cannot do in current context
>
> and then usually crashes. I can see that this is the call to AudioUnitRender in pa_mac_core.c.

> I'm testing with a simple line in from a Maya 44 USB 4in/4out.

I haven't changed any [pa_mac_core.h stream modes], just the default

Ross says:
> I think there are a cluster of related issues in PA/CoreAudio that cause this kind of behavior when "things change" (sample rates, headphone disconnect, and now, apparently device disconnect).

( This is related to #102 )

> a quick hack fix is to check for this error code and return from the IOProc -- that should hopefully prevent the crash (and certainly the error message).
>
> A better fix is to have a notification listener that gets all the necessary changes and does something to reset the AudioUnits.
>
> getting a notification to your app that the device has been unplugged is the subject of some development. In the short term you may need to look for a way to get a notification outside the scope of PortAudio... but fixing the crash I think should be a priority (I can look into it if Bjorn doesn't have time).