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# appendInterpolation(_:format:align:privacy:attributes:)

Appends an interpolated double with the specified attributes.

```
mutating func appendInterpolation(_ number: @autoclosure @escaping () -> Double, format: OSLogFloatFormatting = .fixed, align: OSLogStringAlignment = .none, privacy: OSLogPrivacy = .auto, attributes: String)
```

## Parameters

`number`

The interpolated double. The system automatically wraps this value in a closure.

`format`

The format to apply to the value when the system renders it in a log message. For more information, see [`OSLogFloatFormatting`](/documentation/os/OSLogFloatFormatting). The default value is [`fixed`](/documentation/os/OSLogFloatFormatting/fixed).

`align`

The alignment and minimum number of columns to use when the system renders the value in a log message. For more information, see [`OSLogStringAlignment`](/documentation/os/OSLogStringAlignment). The default value is [`none`](/documentation/os/OSLogStringAlignment/none).

`privacy`

The privacy level of the 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 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 double to a log message.

---

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