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Swift 2 - UnsafeMutablePointer <Void>到對(duì)象

Swift 2 - UnsafeMutablePointer <Void>到對(duì)象

滄海一幻覺(jué) 2019-08-28 10:48:04
Swift 2 - UnsafeMutablePointer <Void>到對(duì)象如果我有一個(gè)像這樣的方法：func someMethod(contextPtr: UnsafeMutablePointer<Void>)我如何從中獲取對(duì)象contextPtr？func someMethod(contextPtr: UnsafeMutablePointer<Void>){         let object:MyObject = contextPtr.memory}得到：'Void'不能轉(zhuǎn)換為'MyObject'什么是秘訣更多詳情：我在這里做的是設(shè)置一個(gè)全局回調(diào)函數(shù)SCNetworkReachability：func callback(reachability:SCNetworkReachability, flags: SCNetworkReachabilityFlags, info: UnsafeMutablePointer<Void>) {     let r:Reachability = info.memory}然后添加回調(diào)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)
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2 回答

?
qq_遁去的一_1

TA貢獻(xiàn)1725條經(jīng)驗(yàn) 獲得超8個(gè)贊


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

如果我們需要傳遞為UnsafeMutablePointer self到異步函數(shù)


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")


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反對(duì) 回復(fù) 2019-08-28
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