Meaning of symbol ^ in Objective C [duplicate]

Answer 1

From the second page of Apple's Blocks Programming Topics:

You use the ^ operator to declare a block variable and to indicate the beginning of a block literal. The body of the block itself is contained within {}, as shown in this example (as usual with C, ; indicates the end of the statement):

Answer 2

That symbol is used to declare block.Blocks are addressable sections of code implemented inline (inside other functions). The inline-edness can be convenient but the real reason why blocks are different to regular functions and function pointers is that they can reference local variables from the scope of the function surrounding their implementation without the invoker of the block needing to know of the surrounding scope variables' existence.
How blocks are implemented (and the consequences)

Answer 3

That symbol is used to declare block.

For more information read here Blocks Programming Topics

Some more info:

Block objects are a C-level syntactic and runtime feature. They are similar to standard C functions, but in addition to executable code they may also contain variable bindings to automatic (stack) or managed (heap) memory. A block can therefore maintain a set of state (data) that it can use to impact behavior when executed.

You can use blocks to compose function expressions that can be passed to API, optionally stored, and used by multiple threads. Blocks are particular useful as a callback because the block carries both the code to be executed on callback and the data needed during that execution.