Could anyone help to explain what does the two rules for unique pointer mean?
Especially confused about "before the call"
Can use existing memory on the client without allocating new memory. When a unique pointer changes during a call from one non-NULL value to another, the pointer is assumed to point to a data object of the same type. Data returned from the server is written into existing storage specified by the value of the unique pointer before the call.
Can orphan memory on the client. Memory referenced by a non-NULL unique pointer may never be freed if the unique pointer changes to NULL during a call and the client does not have another means of dereferencing the storage.
thanks in advance,