GCD
GCD
Intro
Every queue is always First In First Out (FIFO) order.
The queue itself could be on main thread or background thread with varying Quality of services.
Refer Main thread dispatch_main
Refer Background threads dispatch_global
low-level C-based API
NSOperation and NSOperationQueue are Objective-C classes.
NSOperationQueue is objective C wrapper over GCD. If you are using NSOperation, then you are implicitly using Grand Central Dispatch.
Advantages
GCD advantage over NSOperation:
- implementation
For GCD implementation is very light-weight
NSOperationQueue is complex and heavy-weight
Main thread
DispatchQueue.main.async {
self.tableView.reloadData()
}
Background Threads
DispatchQueue.global(qos: .background).async {
doSomething()
}
References
https://developer.apple.com/videos/play/wwdc2015/718/