ios - What type can't be copied in objective C -

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i passing through interview, , there question couldn't answer.

what objects can't copied (property copy) in objective c. , specific details on copy property.

i've looked through web, didn't find information it. there suggestions?

there copyable objects in objective c, confirm nscopying , nssecurecoding protocols. object don't confirm these protocols, not copyable. hope, clears things out.

p.s.: there nsmutablecopying protocol copying mutable version of object well.


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