A null-terminated UTF8 representation of the string.
- iOS 2.0+
- macOS 10.0+
- tvOS 9.0+
- watchOS 2.0+
This C string is a pointer to a structure inside the string object, which may have a lifetime shorter than the string object and will certainly not have a longer lifetime. Therefore, you should copy the C string if it needs to be stored outside of the memory context in which you use this property.