Objective c blocks executing and reusing

Question

I'm trying to understand how objective c blocks work.

As far as I understood: block is just a function with no name.

So for example:

 ^(int a, int b) { return a + b; }; 

1. How can I invoke it?

2. Can I use it multiple times as I would use a function? If I can then how?

3. To what class will 'self' keyword refer to inside the block?

Any help is highly appreciated.

Answer 1

- (void)something
{
    void (^ sample)(void) = ^{
        NSLog(@"I am %@", self);
    };

    sample();
    sample();
}

...or more in keeping with your sample:

int (^ adder)(int a, int b) = ^(int a, int b) { return a + b; };
NSLog(@"Result: %d", adder(5, adder(5, 4)));