---
title: "CGImageMetadataTagCopyPrefix(_:)"
framework: imageio
role: symbol
role_heading: Function
path: "imageio/cgimagemetadatatagcopyprefix(_:)"
---

# CGImageMetadataTagCopyPrefix(_:)

Returns an immutable copy of the tag’s prefix.

## Declaration

```swift
func CGImageMetadataTagCopyPrefix(_ tag: CGImageMetadataTag) -> CFString?
```

## Parameters

- `tag`: The metadata tag from which to fetch the namespace information.

## Return Value

Return Value An immutable string that contains the tag’s prefix. For example, EXIF metadata uses the prefix exif. You are responsible for releasing this string.

## See Also

### Getting the Attributes of the Tag

- [CGImageMetadataTagCopyNamespace(_:)](imageio/cgimagemetadatatagcopynamespace(_:).md)
- [CGImageMetadataTagCopyName(_:)](imageio/cgimagemetadatatagcopyname(_:).md)
- [CGImageMetadataTagCopyValue(_:)](imageio/cgimagemetadatatagcopyvalue(_:).md)
- [CGImageMetadataTagCopyQualifiers(_:)](imageio/cgimagemetadatatagcopyqualifiers(_:).md)