Asynchronous url requests inside dispatch_async

Question

I am trying to implement asynchronous url requests in a particular function, I want all these requests to complete and then do a particular action but the action precedes th

Answer 1

@tkanzakic is on the right path. The correct construct to use is the dispatch_group_t. But the implementation could be improved. By using a semaphore you can launch all your downloads asynchronously and still make sure that you don't have too many running concurrently. Here is a code sample that illustrates how you should use dispatch_group_t as well as make all your downloads parallel:

dispatch_queue_t fetchQ = dispatch_queue_create("Featured Doc Downloader", NULL);
dispatch_group_t fetchGroup = dispatch_group_create();

// This will allow up to 8 parallel downloads.
dispatch_semaphore_t downloadSema = dispatch_semaphore_create(8);

// We start ALL our downloads in parallel throttled by the above semaphore.
for (int i=0; i