---
title: "CFURLCreateCopyAppendingPathExtension(_:_:_:)"
framework: corefoundation
role: symbol
role_heading: Function
path: "corefoundation/cfurlcreatecopyappendingpathextension(_:_:_:)"
---

# CFURLCreateCopyAppendingPathExtension(_:_:_:)

Creates a copy of a given URL and appends a path extension.

## Declaration

```swift
func CFURLCreateCopyAppendingPathExtension(_ allocator: CFAllocator!, _ url: CFURL!, _ extension: CFString!) -> CFURL!
```

## Parameters

- `allocator`: The allocator to use to allocate memory for the new CFURL object. Pass NULL or doc://com.apple.corefoundation/documentation/CoreFoundation/kCFAllocatorDefault to use the current default allocator.
- `url`: The CFURL object to which to append a path extension.
- `extension`: The extension to append to url.

## Return Value

Return Value A copy of url appended with extension. Ownership follows the create rule. See The Create Rule.

## See Also

### Creating a CFURL

- [CFURLCopyAbsoluteURL(_:)](corefoundation/cfurlcopyabsoluteurl(_:).md)
- [CFURLCreateAbsoluteURLWithBytes(_:_:_:_:_:_:)](corefoundation/cfurlcreateabsoluteurlwithbytes(_:_:_:_:_:_:).md)
- [CFURLCreateByResolvingBookmarkData(_:_:_:_:_:_:_:)](corefoundation/cfurlcreatebyresolvingbookmarkdata(_:_:_:_:_:_:_:).md)
- [CFURLCreateCopyAppendingPathComponent(_:_:_:_:)](corefoundation/cfurlcreatecopyappendingpathcomponent(_:_:_:_:).md)
- [CFURLCreateCopyDeletingLastPathComponent(_:_:)](corefoundation/cfurlcreatecopydeletinglastpathcomponent(_:_:).md)
- [CFURLCreateCopyDeletingPathExtension(_:_:)](corefoundation/cfurlcreatecopydeletingpathextension(_:_:).md)
- [CFURLCreateFilePathURL(_:_:_:)](corefoundation/cfurlcreatefilepathurl(_:_:_:).md)
- [CFURLCreateFileReferenceURL(_:_:_:)](corefoundation/cfurlcreatefilereferenceurl(_:_:_:).md)
- [CFURLCreateFromFileSystemRepresentation(_:_:_:_:)](corefoundation/cfurlcreatefromfilesystemrepresentation(_:_:_:_:).md)
- [CFURLCreateFromFileSystemRepresentationRelativeToBase(_:_:_:_:_:)](corefoundation/cfurlcreatefromfilesystemrepresentationrelativetobase(_:_:_:_:_:).md)
- [CFURLCreateFromFSRef(_:_:)](corefoundation/cfurlcreatefromfsref(_:_:).md)
- [CFURLCreateWithBytes(_:_:_:_:_:)](corefoundation/cfurlcreatewithbytes(_:_:_:_:_:).md)
- [CFURLCreateWithFileSystemPath(_:_:_:_:)](corefoundation/cfurlcreatewithfilesystempath(_:_:_:_:).md)
- [CFURLCreateWithFileSystemPathRelativeToBase(_:_:_:_:_:)](corefoundation/cfurlcreatewithfilesystempathrelativetobase(_:_:_:_:_:).md)
- [CFURLCreateWithString(_:_:_:)](corefoundation/cfurlcreatewithstring(_:_:_:).md)