The optimal block size to use when reading or writing this file's data, returned as an
NSNumber object, or
nil if the preferred size is not available (read-only).
- iOS 5.0+
- macOS 10.7+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
static let isPackageKey: URLResourceKey
Key for determining whether the resource is a file package, returned as a Boolean
NSNumber object (read-write in macOS 10.8 and later, read-only in previous versions). A
true value means that the resource is a file package.
This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.Learn more about using Apple's beta software