What are the new type qualifiers introduced with ARC?

Question

Automatic Reference Counting (ARC) introduces some new type qualifiers. I\'ve seen __strong and __weak, but what do they do?

Answer 1

The type qualifiers are __autoreleasing, __strong, __unsafe_unretained, and __weak. The property modifiers are strong, unsafe_unretained, and weak.

Have a look at section 4 of Automatic Reference Counting in the LLVM/Clang documentation.