Swift 2 - UnsafeMutablePointer <Void>到对象

Question

Swift 2 - UnsafeMutablePointer <Void>到对象如果我有一个像这样的方法：func someMethod(contextPtr: UnsafeMutablePointer<Void>)我如何从中获取对象contextPtr？func someMethod(contextPtr: UnsafeMutablePointer<Void>){         let object:MyObject = contextPtr.memory}得到：'Void'不能转换为'MyObject'什么是秘诀更多详情：我在这里做的是设置一个全局回调函数SCNetworkReachability：func callback(reachability:SCNetworkReachability, flags: SCNetworkReachabilityFlags, info: UnsafeMutablePointer<Void>) {     let r:Reachability = info.memory}然后添加回调如下：var context = SCNetworkReachabilityContext(version: 0, info: nil, retain: nil, release: nil, copyDescription: nil)var s = selfwithUnsafeMutablePointer(&s) {     context.info = UnsafeMutablePointer($0)}SCNetworkReachabilitySetCallback(reachability, callback, &context)

Answer 1

struct S {

    var i: Int = 10

}

var first = S()

func foo(contextPtr: UnsafeMutablePointer<Void>){

    let pS = UnsafeMutablePointer<S>(contextPtr)

    pS.memory.i = 100

}

print(first.i) // 10

foo(&first)

print(first.i) // 100

如果我们需要传递为UnsafeMutablePointer self到异步函数

import XCPlayground

XCPlaygroundPage.currentPage.needsIndefiniteExecution = true

import Foundation

// can be struct, class ...

class C {

    let queue = dispatch_queue_create("test", DISPATCH_QUEUE_CONCURRENT)

    var s: String = ""

    func foo() {

        var c = self

        dispatch_async(queue) { () -> Void in

            f(&c)

        }

    }

}

func f(pV: UnsafeMutablePointer<Void>) {

    let pC = UnsafeMutablePointer<C>(pV)

    sleep(1)

    print(pC.memory.s)

}

var c1: C? = C()

c1!.s = "C1"

c1!.foo()        // C1

var c2: C? = C()

c2!.s = "C2"

c2!.foo()        // C2

c1 = nil

c2 = nil

print("test")