Stores data and an accompanying descriptor type to form the basic building block of all Apple Events.


struct AEDesc


The Apple Event Manager uses one or more descriptors to construct Apple event attributes and parameters, object specifiers, tokens, and many other types of data it works with. (Token is defined in AEDisposeToken(_:).) A descriptor consists of an opaque data storage container and a descriptor type that identifies the type of the data stored in the descriptor.

The descriptor type is a structure of type DescType, which in turn is of data type ResType—that is, a four-character code. Descriptor Type Constants lists the constants for the basic descriptor types used by the Apple Event Manager. For information about descriptor types used with object specifiers, see Key Form and Descriptor Type Object Specifier Constants.


Prior to Carbon, the AEDataStorage data type was defined as follows:

typedef Handle AEDataStorage;


Instance Properties

var dataHandle: AEDataStorage!

An opaque storage type that points to the storage for the descriptor data. Your application doesn’t access this data directly—rather, it calls one of the functions AEGetDescDataSize(_:), AEGetDescData(_:_:_:), or AEReplaceDescData(_:_:_:_:). See AEDataStorage.

var descriptorType: DescType

A four-character code of type DescType that indicates the type of data in the structure. See DescType.