Background Execution

I am doing SMTP related app in my application, to send th开发者_StackOverflowe mail.In IOS 4 background execution exceptions for audio,voip,location.How to use network operation.

There is no explicit exception for network access. You can request extra time to complete a task after your app exits but you can't create a daemon process that continually runs in the background.

Apple provides 600 sec to execute background task you can take help with code

 UIApplication *app = [UIApplication sharedApplication];
self.bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
    [app endBackgroundTask:bgTask];
    bgTask = UIBackgroundTaskInvalid;
}];

// Start the long-running task 
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

     while (1) {
    NSLog(@"BGTime left: %f", [UIApplication sharedApplication].backgroundTimeRemaining);
    [self.viewController performSelector:@selector(invokeCuisineSelector)];
          sleep(1);
      }   
});