Question

I have some typedef:

typedef void (^myBlock)(SomeObject);

And I have some object

@interface SomeObject : NSObject
@end

// Method of some arbitrary class
- (void) someMethod1 {
    SomeObject *someObject = [[SomeObject alloc] init];

    myBlock block = ^(SomeObject obj){
        // When _block(someObject)_ will be called inside someQueue - 
        // Is it guaranteed that someObject will be alive, retained inside me?       

        // Do something complex and involving (or not) obj ...    
    }

    dispatch_async(someQueue, ^{
        // Some bunch of code - after which we are sure that 
        // by the next line someMethod1 will run out, so its scope is lost

        block(someObject);
    });
}

The question is put inside the block variable’s block: is it guaranteed that someObject object we pass to the block block inside someQueue queue will be alive and retained inside the block block?

This question is a bit more complex variation of the question I’ve just asked: Does a passing of an object to a block guarantee that its lifecycle will be retained?.

Answer 1

I believe that what you’re asking is the same of the previous question.The only difference here is that you aren’t calling a method inside the block, but you are calling a block.
Maybe my answer wasn’t enough clear: everything is retained inside a block, even a block is retained.

dispatch_async(someQueue, ^{
    // Some bunch of code - after which we are sure that 
    // by the next line someMethod1 will run out, so its scope is lost

    block(someObject);
});

Inside the block you call someObject, so someObject is captured.Also the block is captured.