What does ^ in objective C mean? [duplicate]

Answer 1

It denotes a "block", a piece of code that can be packaged into an object and used later. In your example it specifies a completion handler to be called later, presumably when the user clicks "OK" or some similar button to close an alert.

Blocks can also be used with Grand Central Dispatch and in that case they are used to produce a unit of code that can be run on another thread, both synchronously and asynchronously.

Answer 2

This is a "block", you can read about this in the Apple-Developer-doc, it's mainly used for Multithreading.

Answer 3

It's used as part of the definition of a block:

^(return_type retval) {
  statements;
}

You'll see it as part of declarations of blocks too.