Is DispatchQueue.serial or .concurrent the default?

Question

This is a straightforward question.

let serial = DispatchQueue(label: "serial", attributes: .serial)
let concurrent = DispatchQueue(label: "concurrent", attributes: .concurrent)
let q = DispatchQueue(label: "q")

I do not see a property that I can check for q, which will tell me.

Running on the playground with PlaygroundPage.current.needsIndefiniteExecution = trueserial behavior shows, but I don't want to rely on the playground (like janky with an asynchronous file) or undocumented behavior.

Can someone suggest a hard answer with reference to the documentation?

Answer 1

Swift 3 - nil dispatch_queue_create , . , , DispatchQueue, .

, :

public convenience init(
    label: String,
    attributes: DispatchQueueAttributes = .serial, 
    target: DispatchQueue? = nil)
{
    ...
}

, .