Why does NSError need double indirection? (pointer to a pointer)

Question

This concept seems to trouble me. Why does an NSError object need its pointer passed to a method that is modifying the object? For instance, wouldn\'t just passing a referen

Answer 1

Alternate statement of what n8gray said:

Because you're not receiving an object to send messages to; you're creating the object and returning it. You generally need the pointer-to-an-NSError *-variable argument because you can only use the return statement on one thing at a time, and you're already using it with NO.