---
title: progressHandler
framework: vision
role: symbol
role_heading: Instance Property
path: vision/vnrequestprogressproviding/progresshandler
---

# progressHandler

A block of code executed periodically during a Vision request to report progress on long-running tasks.

## Declaration

```swift
var progressHandler: VNRequestProgressHandler { get set }
```

## Discussion

Discussion The progress handler is an optional method that allows clients of the request to report progress to the user or to display partial results as they become available. The Vision framework may call this handler on a different dispatch queue from the thread on which you initiated the original request, so ensure that your handler can execute asynchronously, in a thread-safe manner.

## See Also

### Tracking Progress

- [indeterminate](vision/vnrequestprogressproviding/indeterminate.md)