dispatch_async Does Not Run - ios

Question

I'm new to queues and threading. Below I have the following code that seeks to run various methods within an asynchronous queue. Each item in the queue will update a count when finished, and when all the items are done in the queue, the update count will be complete and ready for return.
The problem is that when this code runs the last line is called and then, it hangs with no errors and I cannot continue to step through the trace.
__block int masterUpdateCount = 0;
dispatch_group_t group = dispatch_group_create();
dispatch_group_enter(group);
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[self updateStuffWithCompletionCount:^(int updatedItemsCount) {
masterUpdateCount += updatedItemsCount;
}];
[self updateMoreStuffWithCompletionCount:^(int updatedItemsCount) {
masterUpdateCount += updatedItemsCount; // Never gets called
}];
}); // <------ APPLICATION HANGS HERE after calling dispatch_group_wait(group, DISPATCH_TIME_FOREVER);
dispatch_group_wait(group, DISPATCH_TIME_FOREVER);
return masterUpdateCount;
Something I noticed is that the completion blocks never get called, which could very well be why it hangs forever, but my question is why? If it helps, inside the updateStuffWithCompletionCount type methods I'm actually initializing an NSURLSession with an NSURLSessionDataTask and I am in fact running the task by calling [task resume];, so I don't see why the completion wouldn't be called.
Here is what it looks like inside the updateStuffWithCompletionCount method:
- (void) updateStuffWithCompletionCount: (void (^)(int)) completionResult
{
__block int updateCount = 0;
NSString *someURL = #"www.someplace.com";
NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration defaultSessionConfiguration];
NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration: defaultConfigObject delegate: self delegateQueue: [NSOperationQueue mainQueue]];
NSURLSessionDataTask * getDataTask = [defaultSession dataTaskWithURL:[NSURL someURL] completionHandler:^(NSData *data, NSURLResponse *response, NSError *error)
{
if(error == nil)
{
// do stuff, if updated, add to count
updateCount ++;
if(updateCount > 0) {
completionResult(updateCount); // Invoke the completion handler
} else {
completionResult(0); // Invoke the completion handler
}
}
else {
NSLog(#"Error: %#", error);
completionResult(-1);
}
}];
[getDataTask resume];
}
Hopefully an experienced eye can point it out. Appreciated.

Answer 1

Include code for your dataTask please. This line masterUpdateCount += updatedItemsCount; // Never gets called , because its in the completion block which means it doesn't get ran until your datatask is complete, Did you set a breakpoint within your datatask and make sure something its jumping in there? Do you have a NSLog(%#, error.description) line in there in case your getting one? Looks like you may need to do more debugging there.