Instance Property


A callback to the host for transport state information.


iOS, Mac Catalyst, tvOS
@property(copy, nonatomic) AUHostTransportStateBlock transportStateBlock;
@property(copy, atomic) AUHostTransportStateBlock transportStateBlock;


An audio unit accessing this property should cache it in realtime-safe storage before beginning to render.

This version 3 property is bridged to the version 2 HostCallback_GetTransportState and HostCallback_GetTransportState2 callback members in the kAudioUnitProperty_HostCallbacks API.

See Also

Host Callbacks


A callback to the host for musical context information.


Information about the host context in which the audio unit is connected, for display in the audio unit’s view.

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