Type Alias


Callback function used to retain a program-defined information pointer.


typealias CFTreeRetainCallBack = (UnsafeRawPointer?) -> UnsafeRawPointer?



The program-supplied information pointer provided in a CFTreeContext structure.

Return Value

The value to use whenever the information pointer is retained, which is usually the info parameter passed to this callback, but may be a different value if a different value should be used.

See Also


typealias CFTreeApplierFunction

Type of the callback function used by the CFTree apply function.

typealias CFTreeCopyDescriptionCallBack

Callback function used to provide a description of the program-defined information pointer.

typealias CFTreeReleaseCallBack

Callback function used to release a previously retained program-defined information pointer.

Beta Software

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