grand-central-dispatch

This question already has answers here : What's the best way to iterate over results from an APi, and know when it's finished? (1 answer) Swift Closures in for loop (1 answer) How do you run code after an async call finishes and the code is outside of the asyn function in swift3 (1 answer) Closed last year . Trying to make my for loop behave synchronously when I am making an asynchronous call in each iteration of the loop. I have a feeling I will need to use Grand Central Dispatch in some way but not sure. func test(strings: [String], completion: @escaping ((_ value: [String]) -> Void)) { var

public class Account { // MARK: Initializer // Custom initializer // MARK: Stored Properties let concurrentQueue: DispatchQueue = DispatchQueue( label: "concurrentQueue", qos: DispatchQoS.userInitiated, attributes: [DispatchQueue.Attributes.concurrent] ) private var _name: String public name: String { get { return self.concurrentQueue.sync { return self._name } } set { self.concurrentQueue.async(flags: .barrier) { self._name = newValue } } } } Let's say you have a class like above where you want thread safety. What is the difference between the getter in the Account class and defining the

I had a completely functioning codebase written in C++11 that used Grand Central Dispatch parallel processing, specifically dispatch_apply to do the basic parallel for loop for some trivial game calculations. Since upgrading to Sierra, this code still runs, but each block is run in serial -- the cout statement shows that they are being executed in serial order, and CPU usage graph shows no parallel working on. Queue is defined as: workQueue = dispatch_queue_create("workQueue", DISPATCH_QUEUE_CONCURRENT); And the relevant program code is: case Concurrency::Parallel: { dispatch_apply(stateMap

I've got this method -(void)addObjectToProcess(NSObject*)object; and i want this method to add the object to process queue which can process up to 4 objects in parallel. i've created my own dispatch_queue and semhphore _concurrentQueue = dispatch_queue_create([queue_id UTF8String],DISPATCH_QUEUE_CONCURRENT); _processSema = dispatch_semaphore_create(4); and the implementation of the method is: -(void)addObjectToProcess(NSObject*)object { dispatch_semaphore_wait(self.processSema, DISPATCH_TIME_FOREVER); __weak MyViewController* weakSelf = self; dispatch_async(self.concurrentQueue, ^{ // PROCESS.

I am using the CoreLocation's geocoder to get the CLLocation coordinates for multiple map items. The geocoder calls a completion block on completion for each item. How do I create a similar block functionality which is called when all of these containing asynchronous geocoder calls have been completed? (I could use a manual counter. But there must be a more elegant solution) Here's my geocoding function so far. It loops through an array of location items and starts a new geocoding process for each. -(void)geoCodeAllItems { for (EventItem* thisEvent in [[EventItemStore sharedStore] allItems]) {

//my_serial_queue is a serial_dispatch_queue dispatch_async(my_serial_queue, ^{ //access a shared resource such as a bank account balance [self changeBankAccountBalance]; }); If I submit 100 tasks that each access and mutate a bank account balance, I understand that a serial queue will execute each task sequentially, but do these tasks finish sequentially as well when using dispatch_async? What if task #23 that I submit asynchronously to the serial queue takes a really long time to finish? Would task #24 start only when task #23 is done, or would task #24 begin before task #23 is done? If so,