what does the caret sign mean in Objective-C?

Question

There is a piece of code like

typedef void (^SignIn) (NSString *email, NSString *password);

What does the ^ mean before SignIn? Is this Objective-C specific usage?

[here](http://stackoverflow.com/a/17691526/766570) is some block syntax explanation using examples — abbood, Jul 28 '13 at 05:46

score 4 · Answer 1 · answered Jul 28 '13 at 02:36

4

It's the syntax for blocks.

That typedef declares SignIn to mean a block which takes two NSString* arguments and returns void (i.e. nothing).

answered Jul 28 '13 at 02:36

Jeremy Roman

score 1 · Answer 2 · answered Jul 28 '13 at 02:47

1

It is a block.

For a guide to understanding blocks, see this tutorial

Unless, you already know what a block is, and you just didn't know what the caret was for.

answered Jul 28 '13 at 02:47

CaptJak

2 Answers2