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# appendInterpolation(_:privacy:attributes:)

Appends an interpolated object description with the specified attributes.

```
mutating func appendInterpolation(_ argumentObject: @autoclosure @escaping () -> NSObject, privacy: OSLogPrivacy = .auto, attributes: String)
```

## Parameters

`argumentObject`

The interpolated object, which the system automatically wraps in a closure. The object itself doesn’t appear in the log message. Instead, the system calls the object’s <doc://com.apple.documentation/documentation/ObjectiveC/NSObjectProtocol/description> method and incorporates the value it returns.

`privacy`

The privacy level of the interpolated value, which the system applies when it renders the value in a log message. For more information, see [`OSLogPrivacy`](/documentation/os/OSLogPrivacy). The default value is [`auto`](/documentation/os/OSLogPrivacy/auto).

`attributes`

Additional information about the interpolated value. Tools that process log messages interpret these attributes, which you typically provide as key-value pairs. For example, Instruments processes any e_ngineering types_ you embed in this value. For more information, see [Instruments Developer Help](https://help.apple.com/instruments/developer/mac/current/#/devcd5016d31).

## Discussion

> Important:
> You don’t call this method directly. Instead, the framework calls it automatically when you append an interpolated object description to a log message.

---

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