Swift 2 - UnsafeMutablePointer <Void>到對象如果我有一個像這樣的方法：func someMethod(contextPtr: UnsafeMutablePointer<Void>)我如何從中獲取對象contextPtr？func someMethod(contextPtr: UnsafeMutablePointer<Void>){
let object:MyObject = contextPtr.memory}得到：'Void'不能轉換為'MyObject'什么是秘訣更多詳情：我在這里做的是設置一個全局回調函數SCNetworkReachability：func callback(reachability:SCNetworkReachability, flags: SCNetworkReachabilityFlags, info: UnsafeMutablePointer<Void>) {
let r:Reachability = info.memory}然后添加回調如下：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)
2 回答
qq_遁去的一_1
TA貢獻1725條經驗 獲得超8個贊
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
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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