Returns the dictionary key used by a directory to identify a given file wrapper.
- iOS 4.0+
- macOS 10.0+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
The child file wrapper for which you want the key.
Dictionary key used to store the file wrapper in the directory’s list of file wrappers. The dictionary key is a unique filename, which may not be the same as the passed-in file wrapper's preferred filename if more than one file wrapper in the directory's dictionary of children has the same preferred filename. See Accessing File Wrapper Identities in File System Programming Guide for more information about the file-wrapper list structure. Returns
nil if the file wrapper specified in
child is not a child of the directory.
This method raises
NSInternal if the receiver is not a directory file wrapper.