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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 Mac OS X v10.2 and later.

Functions

CFNullGetTypeID

Returns the type identifier for the CFNull opaque type.

CFTypeID CFNullGetTypeID (
   void
);

Return Value

The type identifier for the CFNull opaque type.

Availability

• Available in Mac OS X v10.2 and later.

Declared In

CFBase.h

Data Types

CFNullRef

A reference to a CFNull object.

typedef const struct __CFNull *CFNullRef;

Availability

• Available in Mac OS X v10.2 and later.

Declared In

CFBase.h

Constants

Predefined Value

Predefined CFNull object.

const CFNullRef kCFNull;

Constants

kCFNull

The singleton CFNull object.

Available in Mac OS X v10.2 and later.

Declared in CFBase.h

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