---
title: FSExtentType.zeroFill
framework: fskit
role: symbol
role_heading: Case
path: fskit/fsextenttype/zerofill
---

# FSExtentType.zeroFill

An extent type to indicate uninitialized data.

## Declaration

```swift
case zeroFill
```

## Discussion

Discussion Only use this extent type in file systems that support sparse files, and only then to represent ranges in the file that aren’t allocated yet.

## See Also

### Working with extent types

- [FSExtentType.data](fskit/fsextenttype/data.md)
- [FSExtentType.readOnly](fskit/fsextenttype/readonly.md)