ViewController.swift

//
//  ViewController.swift
//  a
//
//  Created by Tomoya Hirano on 2021/06/15.
//

import UIKit

class ViewController: UIViewController {
    static let dispatchQueue = DispatchQueue(label: "test")
    override func viewDidLoad() {
        super.viewDidLoad()
        
        ViewController.dispatchQueue.async {
            Thread.current.name = "test thread"
            print("done")
        }
    }
    
    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        threadIDs().forEach { id in
            print(threadName(id: id))
        }
    }
    
    func threadIDs() -> [UInt32] {
        var threadList = UnsafeMutablePointer<UInt32>.allocate(capacity: 1)
        var threadCount = UInt32(MemoryLayout<mach_task_basic_info_data_t>.size / MemoryLayout<natural_t>.size)
        let result = withUnsafeMutablePointer(to: &threadList) {
            $0.withMemoryRebound(to: thread_act_array_t?.self, capacity: 1) {
                task_threads(mach_task_self_, $0, &threadCount)
            }
        }
        if result != KERN_SUCCESS { return [] }
        var ids: [UInt32] = []
        for index in (0..<Int(threadCount)) {
            ids.append(threadList[index])
        }
        return ids
    }
    
    func threadName(id: UInt32) -> String {
        var threadInfo = thread_extended_info()
        var threadInfoCount = UInt32(THREAD_INFO_MAX)
        let result = withUnsafeMutablePointer(to: &threadInfo) {
            $0.withMemoryRebound(to: integer_t.self, capacity: 1) {
                thread_info(id, UInt32(THREAD_EXTENDED_INFO), $0, &threadInfoCount)
            }
        }
        let name = withUnsafePointer(to: threadInfo.pth_name) {
            $0.withMemoryRebound(to: UInt8.self, capacity: MemoryLayout.size(ofValue: $0)) {
                String(cString: $0)
            }
        }
        return name
    }
}