Wow. Haven’t seen that syntax in a long time. That was one of the various syntactic structures explored during the development of blocks. It was eventually rejected because it was too imprecise in declaring intent and the resulting behavior would have been confusing. Consider a scope with three blocks, two of which declare a variable … Read more
This is a FIFO queue in GCD: dispatch_queue_t serialQueue = dispatch_queue_create(“com.blah.queue”, DISPATCH_QUEUE_SERIAL); … dispatch_async(serialQueue, ^{ //block1 }); dispatch_async(serialQueue, ^{ //block2 });
It sounds like you wish to communicate with an existing class which is designed to take a delegate object. There are a number of approaches, including: using a category to add block-based variants of the appropriate methods; use a derived class to add the block-based variants; and write a class which implements the protocol and … Read more
In the latest clang version Apple clang version 4.0 (tags/Apple/clang-421.1.48) (based on LLVM 3.1svn), i.e. Xcode 4.4+, the __typeof__((__typeof__(self))self) trick is not necessary anymore. The __weak typeof(self) bself = self; line will compile just fine.
I’m not entirely sure what you’re trying to do there – your callback is a block… is that intentional? I would expect your method to look something like this: – (void)signInAccountWithUserName:(NSString *)userName password:(NSString *)password; If the intention of your callback is to execute some additional code (specified when you call the method) on completion, then … Read more
I created a light-weight solution for this. It’s called Sequencer and it’s up on github. It makes chaining API calls (or any other async code) easy and straightforward. Here’s an example of using AFNetworking with it: Sequencer *sequencer = [[Sequencer alloc] init]; [sequencer enqueueStep:^(id result, SequencerCompletion completion) { NSURL *url = [NSURL URLWithString:@”https://alpha-api.app.net/stream/0/posts/stream/global”]; NSURLRequest *request … Read more
@KennyTM and @David are correct, but your code is potentially wrong. Here’s why: When creating an NSArray with objects, it will retain the objects put into it. In the case of blocks, it’s using the Block_retain function. This means that the array has retained the blocks that you created, but that live on the stack … Read more
Assign whatever identifier you want using dispatch_queue_set_specific(). You can then check your identifier using dispatch_get_specific(). Remember that dispatch_get_specific() is nice because it’ll start at the current queue, and then walk up the target queues if the key isn’t set on the current one. This usually doesn’t matter, but can be useful in some cases.