Conditionally archives a given object.
- macOS 10.0–10.13Deprecated
The object to archive.
This method overrides the superclass implementation to allow
object to be encoded only if it is also encoded unconditionally by another object in the object graph. Conditional encoding lets you encode one part of a graph detached from the rest. (See Archives and Serializations Programming Guide for more information.)
This method should be invoked only from within an
encode method. If
NSArchiver object encodes it unconditionally as
nil. This method raises an
NSInvalid if no root object has been encoded.