Returns a human-presentable failure reason for a given error.
- iOS 2.0+
- macOS 10.5+
- tvOS 9.0+
- watchOS 2.0+
- Core Foundation
The CFError to examine. If this is not a valid CFError, the behavior is undefined.
A localized, human-presentable failure reason for
NULL if no user-presentable string is available. Ownership follows the The Create Rule.
The failure reason is a complete sentence which describes why the operation failed. In many cases this will be just the "because" part of the description (but as a complete sentence, which makes localization easier). For example, an error description "Could not save file 'Letter' in folder 'Documents' because the volume 'MyDisk' doesn't have enough space." might have a corresponding failure reason, "The volume 'MyDisk' doesn't have enough space."
By default, this function looks for a value for the
k key in the user info dictionary. Toll-free bridged instances of
NSError might provide additional behaviors for manufacturing this value.
When you create a CFError, you should try to make sure the return value is human-presentable and localized by providing a value for
k in the user info dictionary.