What's the difference between unshare() and copy()?

Question

Both unshare() and copy() are used for copying an array, but I can't see the difference.

Answer 1

Unshare

As it says on Apple documentation unshare is to ensure that the copy of the array is unique, so when you call unshare you get non shared copy of the array, that could be the same array if that was the only reference to the array.

Copy

On the other hand copy forces the copy of the array and returns a new array containing the copied items.

So if you want to have 2 independent copies of the array you should use copy on other case you can use unsare to ensure the array has no other references.

Answer 2

unshare() will do nothing if the callee is already not shared. copy() will copy it regardless.