sample : sendAsynchronousRequest

gistfile1.m

    xmlData = [[NSMutableData alloc] init];
    NSURL *url = [NSURL URLWithString:
    @"http://forrums.bignerdranch.com/smartfeed.php?"
    @"limit=NO_LIMIT&count_limit20&sort_by=standard&"
    @"feed_type=RSS2.0&feed_style=COMPACT"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    //connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
    NSOperationQueue *queue = [[NSOperationQueue alloc]init];
    [NSURLConnection sendAsynchronousRequest:request
                                       queue:queue
                           completionHandler:^(NSURLResponse *response, NSData *data, NSError *error){
                               if (error) {
                                   xmlData = nil;
                                   NSLog(@"error:%@", error.localizedDescription);
                               }
                               [xmlData appendData:data];
                           }];