---
title: kCFURLFileResourceIdentifierKey
framework: corefoundation
role: symbol
role_heading: Global Variable
path: corefoundation/kcfurlfileresourceidentifierkey
---

# kCFURLFileResourceIdentifierKey

Key for the resource’s unique identifier, returned as a CFType object.

## Declaration

```swift
let kCFURLFileResourceIdentifierKey: CFString!
```

## Discussion

Discussion This identifier can be used to determine equality between file system resources with the CFEqual(_:_:) function. Two resources are equal if they have the same file-system path or if their paths link to the same inode on the same file system. The value of this identifier is not persistent across system restarts.

## See Also

### Constants

- [kCFURLNameKey](corefoundation/kcfurlnamekey.md)
- [kCFURLLocalizedNameKey](corefoundation/kcfurllocalizednamekey.md)
- [kCFURLPathKey](corefoundation/kcfurlpathkey.md)
- [kCFURLIsRegularFileKey](corefoundation/kcfurlisregularfilekey.md)
- [kCFURLIsDirectoryKey](corefoundation/kcfurlisdirectorykey.md)
- [kCFURLIsSymbolicLinkKey](corefoundation/kcfurlissymboliclinkkey.md)
- [kCFURLIsVolumeKey](corefoundation/kcfurlisvolumekey.md)
- [kCFURLIsPackageKey](corefoundation/kcfurlispackagekey.md)
- [kCFURLIsSystemImmutableKey](corefoundation/kcfurlissystemimmutablekey.md)
- [kCFURLIsUserImmutableKey](corefoundation/kcfurlisuserimmutablekey.md)
- [kCFURLIsHiddenKey](corefoundation/kcfurlishiddenkey.md)
- [kCFURLHasHiddenExtensionKey](corefoundation/kcfurlhashiddenextensionkey.md)
- [kCFURLCreationDateKey](corefoundation/kcfurlcreationdatekey.md)
- [kCFURLContentAccessDateKey](corefoundation/kcfurlcontentaccessdatekey.md)
- [kCFURLContentModificationDateKey](corefoundation/kcfurlcontentmodificationdatekey.md)