Framework
The CFNull opaque type defines a unique object used to represent null values in collection objects (which don’t allow NULL values). CFNull objects are neither created nor destroyed. Instead, a single CFNull constant object—k—is defined and is used wherever a null value is needed.
The CFNull opaque type is available in macOS 10.2 and later.
func CFNullReturns the type identifier for the CFNull opaque type.
class CFNullA reference to a CFNull object.
Predefined CFNull object.
The CFFileDescriptor provides an opaque type to monitor file descriptors for read and write activity via CFRunLoop.
CFStringTokenizer allows you to tokenize strings into words, sentences or paragraphs in a language-neutral way. It supports languages such as Japanese and Chinese that do not delimit words by spaces, as well as de-compounding German compounds. You can obtain Latin transcription for tokens. It also provides language identification API.