---
title: uniqueID
framework: avfoundation
role: symbol
role_heading: Instance Property
path: avfoundation/avcapturephotosettings/uniqueid
---

# uniqueID

A unique identifier for this photo settings instance.

## Declaration

```swift
var uniqueID: Int64 { get }
```

## Mentioned in

Tracking photo capture progress

## Discussion

Discussion Creating a AVCapturePhotoSettings instance automatically assigns a unique value to this property. Use this property to track a photo capture request. After you call the capturePhoto(with:delegate:) method, the photo capture output calls your delegate object to provide information about the progress and results of the capture. Each delegate method includes a AVCaptureResolvedPhotoSettings whose uniqueID property matches the uniqueID value of the AVCapturePhotoSettings object you used to request capture. It is illegal to reuse a AVCapturePhotoSettings instance for multiple captures. Calling the capturePhoto(with:delegate:) method throws an exception (invalidArgumentException) if the settings object’s uniqueID value matches that of any previously used settings object.

## See Also

### Inspecting settings

- [format](avfoundation/avcapturephotosettings/format.md)
- [processedFileType](avfoundation/avcapturephotosettings/processedfiletype.md)
- [rawFileType](avfoundation/avcapturephotosettings/rawfiletype.md)
- [rawPhotoPixelFormatType](avfoundation/avcapturephotosettings/rawphotopixelformattype.md)