Meanwhile I found a solution that I get at least compiled and that doesn’t crash. I’m using IOUserAudioCustomProperty to add an icon property but the icon still doesn’t appear. In the console I’m seeing this output, which makes me think I’m not completely wrong with this approach.
standard 17:47:07.554960+0200 Audio MIDI Setup HALC_ProxyObject.cpp:881 HALC_ProxyObject::GetPropertyData ('icon', 'glob', 0, DCFURL): got an error from the server, 0x77686174
fehler 17:47:07.554982+0200 Audio MIDI Setup HALC_ShellObject.mm:449 HALC_ShellObject::GetPropertyData: call to the proxy failed, Error: 2003329396 (what)
fehler 17:47:07.554996+0200 Audio MIDI Setup HALPlugIn.cpp:295 HALPlugIn::ObjectGetPropertyData: got an error from the plug-in routine, Error: 2003329396 (what)
fehler 17:47:07.555026+0200 Audio MIDI Setup CAHALAudioObject::GetPropertyData: got an error getting the property data, Error: 2003329396 (what)
Do you have any idea how can I set the correct DCFURL for my icon which is inside my dexts resources?