Network request comes back after the controller is popped

Question

I make a network request within a viewcontroller, the simplified code is as below:

- (void)viewDidLoad {

    [super viewDidLoad];

    [self http_request];

}

- (void)http_request {

    dispatch_async(gAsynQueueT, ^{

        NSString *response;

        NSURL *url = [NSURL URLWithString:@"http://www.google.com"];

        ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];

        sleep(5); //leave some time for poping this controller

        [request startSynchronous];

        NSError *error = [request error];

        if (!error) {

           response = [request responseString];

        }

        dispatch_async(gMainQueueT, ^{

            _data = response;  //_data is an global variable

        });

    });


}

Before the network request coming back, I popped the controller. I think this should lead to memory leak, cause when the network request came back the controller is released. But I found nothing wrong with instrument tool.

So, how to expain this situation. Thanks~

Answer 1

You already used dispatch_async(gAsynQueueT, {...}) and it will run on another thread.

And in block, you didn't use view controller's property so I think there is no reason for memory leak.

block was already dispatched to queue so it isn't related to view controller anyway.