---
title: completionHandler
framework: vision
role: symbol
role_heading: Instance Property
path: vision/vnrequest/completionhandler
---

# completionHandler

The completion handler the system invokes after the request finishes processing.

## Declaration

```swift
var completionHandler: VNRequestCompletionHandler? { get }
```

## Discussion

Discussion Vision executes the completion handler on the same queue that it executes the request; however, this queue differs from the one where you called perform(_:).

## See Also

### Configuring a Request

- [VNRequestCompletionHandler](vision/vnrequestcompletionhandler.md)
- [preferBackgroundProcessing](vision/vnrequest/preferbackgroundprocessing.md)
- [results](vision/vnrequest/results.md)
- [revision](vision/vnrequest/revision.md)
- [usesCPUOnly](vision/vnrequest/usescpuonly.md)