Title: AUv2: Property Listener Callback Lifetime During AudioComponentInstanceDispose I’m developing a macOS Audio Unit v2 (AUv2) instrument in C++ and investigating the correct lifetime and synchronization requirements for property-listener callbacks. I would appreciate clarification from Apple engineers or developers with direct AUv2 implementation experience. Specifically: Does AudioComponentInstanceDispose guarantee that the Audio Unit’s Close operation has completed before the call returns? Does disposal guarantee that all property-listener callbacks registered through AudioUnitAddPropertyListener have finished executing before the instance and its associated callback data can be destroyed? What are the documented guarantees of AudioUnitRemovePropertyListenerWithUserData regarding callbacks that are currently executing or already queued? Is there a documented synchronization procedure that allows an AUv2 plug-in to safely release listener callback state during instance shutdown? Are there host-ordering requirements or documented assumptions that plug-in developers must follow when registering, removing, and destroying property listeners? My implementation is designed to avoid use-after-free, concurrent access to destroyed objects, and unsafe callback-data reclamation. I want to base the implementation on documented Apple API guarantees rather than assumptions about host behaviour. If relevant, please point me to the authoritative documentation or recommended implementation pattern. Environment: macOS 12 Monterey, Xcode 14.2, AUv2 instrument, C++.

AUv2: Property Listener Callback Lifetime During AudioComponentInstanceDispose

Title: AUv2: Property Listener Callback Lifetime During AudioComponentInstanceDispose

I’m developing a macOS Audio Unit v2 (AUv2) instrument in C++ and investigating the correct lifetime and synchronization requirements for property-listener callbacks.

I would appreciate clarification from Apple engineers or developers with direct AUv2 implementation experience.

Specifically:

Does AudioComponentInstanceDispose guarantee that the Audio Unit’s Close operation has completed before the call returns?
Does disposal guarantee that all property-listener callbacks registered through AudioUnitAddPropertyListener have finished executing before the instance and its associated callback data can be destroyed?
What are the documented guarantees of AudioUnitRemovePropertyListenerWithUserData regarding callbacks that are currently executing or already queued?
Is there a documented synchronization procedure that allows an AUv2 plug-in to safely release listener callback state during instance shutdown?
Are there host-ordering requirements or documented assumptions that plug-in developers must follow when registering, removing, and destroying property listeners?

My implementation is designed to avoid use-after-free, concurrent access to destroyed objects, and unsafe callback-data reclamation.

I want to base the implementation on documented Apple API guarantees rather than assumptions about host behaviour.

If relevant, please point me to the authoritative documentation or recommended implementation pattern.

Environment: macOS 12 Monterey, Xcode 14.2, AUv2 instrument, C++.