How can I retain a local variable that is set in a block?

Question

So I have:

@interface testAppControl : NSObject
{
    NSString *s;
}

and then in my block I want to do

[SendAPI setGroupWithNam         


        

Answer 1

It seem as you are performing an asynchronous operation and when the completion block is called you have already left the function/scope where s was defined.

consider declaring s in a "global" scope (like a class variable or property) then as long as your class instance is alive, you will be able to read the results set by the block.

I would recommend using a property, and capturing a "weak self" pointer in the block, in order to avoid bad memory access in case that the instance holding s was deallocated.