The character contents of the receiver as an
- iOS 3.2+
- macOS 10.0+
- tvOS 9.0+
- watchOS 2.0+
Attachment characters are not removed from the value of this property.
For performance reasons, this property returns the current backing store of the attributed string object. If you want to maintain a snapshot of this as you manipulate the returned string, you should make a copy of the appropriate substring.
This primitive property must guarantee efficient access to an attributed string’s characters; subclasses should implement it to execute in O(1) time.