CFNull Reference

Overview

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—kCFNull—is defined and is used wherever a null value is needed.

The CFNull opaque type is available in OS X v10.2 and later.

Functions

CFNullGetTypeID

Returns the type identifier for the CFNull opaque type.

CFTypeID CFNullGetTypeID (
   void
);

Data Types

CFNullRef

A reference to a CFNull object.

typedef const struct __CFNull *CFNullRef;

Constants

Predefined Value

Predefined CFNull object.

const CFNullRef kCFNull;

Constants

kCFNull

The singleton CFNull object.

Available in iOS 2.0 and later.

Declared in CFBase.h.