---
title: "appendInterpolation(_:format:align:privacy:attributes:)"
framework: os
role: symbol
role_heading: Instance Method
path: "os/osloginterpolation/appendinterpolation(_:format:align:privacy:attributes:)-8bi90"
---

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

Appends an interpolated double with the specified attributes.

## Declaration

```swift
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 doc://com.apple.os/documentation/os/OSLogFloatFormatting. The default value is doc://com.apple.os/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 doc://com.apple.os/documentation/os/OSLogStringAlignment. The default value is doc://com.apple.os/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 doc://com.apple.os/documentation/os/OSLogPrivacy. The default value is doc://com.apple.os/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 https://help.apple.com/instruments/developer/mac/current/#/devcd5016d31.

## Discussion

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.

## See Also

### Appending Doubles

- [appendInterpolation(_:format:align:privacy:)](os/osloginterpolation/appendinterpolation(_:format:align:privacy:)-6mu00.md)