Function

AudioUnitGetProperty(_:_:_:_:_:_:)

Gets the value of an audio unit property.

Declaration

func AudioUnitGetProperty(_ inUnit: AudioUnit, _ inID: AudioUnitPropertyID, _ inScope: AudioUnitScope, _ inElement: AudioUnitElement, _ outData: UnsafeMutableRawPointer, _ ioDataSize: UnsafeMutablePointer<UInt32>) -> OSStatus

Parameters

inUnit

The audio unit that you want to get a property value from.

inID

The identifier for the property.

inScope

The audio unit scope for the property.

inElement

The audio unit element for the property.

outData

On successful output, the current value for the specified audio unit property. Set this parameter to NULL when calling this function if you only want to determine how much memory to allocate for a variable size property.

ioDataSize

On input, the expected size of the property value, as pointed to by the outData parameter. On output, the size of the data that was returned.

Return Value

A result code.

Discussion

Some Core Audio property values are C types and others are Core Foundation objects.

If you call this function to retrieve a value that is a Core Foundation object, then this function—despite the use of “Get” in its name—duplicates the object. You are responsible for releasing the object, as described in The Create Rule in Memory Management Programming Guide for Core Foundation.