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    Chapter 5: Blocks Implementation > Capturing Objects

    Capturing Objects

    We saw examples using integer variables. Next, let’s see what will happen when an object is used from a Block. In the next source code, an object of the NSMutableArray class is created and the assigned variable has ownership of it. Because the scope of the variable, which qualified with __strong, is left immediately, the object is released and discarded.

    {
        id array = [[NSMutableArray alloc] init];
    }

    Listing 5–7 uses the variable “array” in a Block literal.

    Listing 5–7. Capturing an object

    blk_t blk;
    {
        id array = [[NSMutableArray alloc] init];
        blk = [^(id obj) {
            [array addObject:obj];
            NSLog(@"array count = %ld", [array count]);
        } copy];
     }
    blk([[NSObject alloc] init]);
    blk([[NSObject alloc] init]);

    blk([[NSObject alloc] init]);

      

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