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# vImageCVImageFormat_GetUserData(_:)

Returns the user data of a Core Video image format.

```
func vImageCVImageFormat_GetUserData(_ format: vImageConstCVImageFormat) -> UnsafeMutableRawPointer!
```

## Parameters

`format`

The Core Video image format to query.

## Return Value

The address of `userData;` `NULL` if `userData` isn’t set.

## Discussion

The functions that create Core Video image formats, such as [`vImageCVImageFormat_CreateWithCVPixelBuffer(_:)`](/documentation/Accelerate/vImageCVImageFormat_CreateWithCVPixelBuffer(_:)), return a [`vImageCVImageFormat`](/documentation/Accelerate/vImageCVImageFormat). The following code shows how you create a [`vImageConstCVImageFormat`](/documentation/Accelerate/vImageConstCVImageFormat) representation of a [`vImageCVImageFormat`](/documentation/Accelerate/vImageCVImageFormat) instance to pass to [`vImageCVImageFormat_GetUserData(_:)`](/documentation/Accelerate/vImageCVImageFormat_GetUserData(_:)):

```swift
let userData = withUnsafeBytes(of: cvImageFormat) { bytes in
    let format = bytes.assumingMemoryBound(
        to: vImageConstCVImageFormat.self).first!
    
    return vImageCVImageFormat_GetUserData(format)
}
```

---

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