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# AUImplementorDisplayNameWithLengthCallback

A block called to obtain a parameter node’s display name, possibly truncated to a desired length.

```
typealias AUImplementorDisplayNameWithLengthCallback = (AUParameterNode, Int) -> String
```

## Discussion

This block is only of interest to audio unit subclasses.

The block returns a truncated parameter node display name.

The block takes the following parameters:

- node: The parameter node to query.
- desiredLength: The desired length, in characters, of the display name.

## See Also

[`implementorDisplayNameWithLengthCallback`](/documentation/AudioToolbox/AUParameterNode/implementorDisplayNameWithLengthCallback)

The callback for obtaining an abbreviated version of a parameter node display name.


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