Break out of nested blocks Objective-C

Question

If I have a block inside a block inside a block, etc... how would I "stop" executing any further blocks.

void (^simpleBlock)(void) = ^{
    //block A
    void (^simpleBlock)(void) = ^{
        //block B

        //something happened, stop block C from executing...

        void (^simpleBlock)(void) = ^{
            //block C
        };
    };
};

Answer 1

If you want to terminate the execution of the block itself, you can simply return from the block, like this:

void (^simpleBlock)(void) = ^{
    //block B

    //something happened, stop block C from executing...
    return;

    void (^simpleBlock)(void) = ^{
        //block C
    };
};

If block C is running already, and you wish to let it know that it should quit as soon as possible, you can do this:

// Set up a flag that is shared among all blocks
__block BOOL blockCShouldStop = NO;
void (^simpleBlock)(void) = ^{
    //block A
    void (^simpleBlock)(void) = ^{
        //block B

        //something happened, stop block C from executing...
        blockCShouldStop = YES; // <<== Set the flag
        return;

        void (^simpleBlock)(void) = ^{
            //block C
            ...
            if (blockCShouldStop) { // <<== Check the flag
                return;
            }
        };
    };
};