How can I access a __block variable, after the block has completed? [duplicate]

Answer 1

The code in the block is run asynchronously. So the code after the block is run before the code in the block has had a chance to run (or certainly complete at least).

see this tutorial on developer.apple.com Working with Blocks

Answer 2

You don't. Well, you can just access it like you are. But the purpose of the block is that it will be called asynchronously after some delay when the information is actually available so you should do your processing in the block or call another method from the block to do it.

Answer 3

You can use them outside block just like any other variable.

In your current code this log will print nil, because code inside the block gets executed asynchronously, in this case - when the search results return.

If you want meaningful value from myObject, you should really put your log inside the block, after myObject assignment.

See the order of execution in comments:

 __block PFObject *myObject = nil;             //1

PFQuery *query = [PFQuery queryWithClassName:@"ClassName"];   //2
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {  //3
   if (objects.count)     //5
       myObject = [objects lastObject];   //6
}];                                       //7

NSLog(@"%@",myObject);   //4