---
title: "CVDisplayLinkSetOutputCallback(_:_:_:)"
framework: corevideo
role: symbol
role_heading: Function
path: "corevideo/cvdisplaylinksetoutputcallback(_:_:_:)"
---

# CVDisplayLinkSetOutputCallback(_:_:_:)

Sets the renderer output callback function.

## Declaration

```swift
func CVDisplayLinkSetOutputCallback(_ displayLink: CVDisplayLink, _ callback: CVDisplayLinkOutputCallback?, _ userInfo: UnsafeMutableRawPointer?) -> CVReturn
```

## Parameters

- `displayLink`: The display link whose output callback you want to set.
- `callback`: The callback function to set for this display link. See doc://com.apple.corevideo/documentation/CoreVideo/CVDisplayLinkOutputCallback for more information about implementing this function.
- `userInfo`: A pointer to user data.

## Return Value

Return Value A Core Video result code. See Core Video Constants for possible values.

## Discussion

Discussion The display link invokes this callback whenever it wants you to output a frame.

## See Also

### Configuring Display Links

- [CVDisplayLinkSetCurrentCGDisplay(_:_:)](corevideo/cvdisplaylinksetcurrentcgdisplay(_:_:).md)
- [CVDisplayLinkSetCurrentCGDisplayFromOpenGLContext(_:_:_:)](corevideo/cvdisplaylinksetcurrentcgdisplayfromopenglcontext(_:_:_:).md)
- [CVDisplayLinkSetOutputHandler(_:_:)](corevideo/cvdisplaylinksetoutputhandler(_:_:).md)
- [CVDisplayLinkOutputHandler](corevideo/cvdisplaylinkoutputhandler.md)