Swift3 通过单例重复创建对象，但对象地址不同

这是我的代码：

class Test {
    static let sharedInstance = Test()
    private init() {}
}

var obj1 = Test.sharedInstance
var obj2 = Test.sharedInstance

withUnsafePointer(to: &obj1) {
    print(" obj1 value \(obj1) has address: \($0)")
}

withUnsafePointer(to: &obj2) {
    print(" obj2 value \(obj2) has address: \($0)")
}

日志：

obj1值测试的地址为：0x0000000112cc5bf8

obj2值测试的地址为：0x0000000112C5C00

---

提前感谢！

您的代码显示了两个变量的地址，

obj1

和

obj2

import Foundation

class Test {
    static let sharedInstance = Test()
    init() {} //Make initializer accessible for testing.
}

var obj1 = Test.sharedInstance
var obj2 = Test.sharedInstance

withUnsafePointer(to: &obj1) {
    print(" var obj1 is located at address: \($0)")
}
withUnsafePointer(to: &obj2) {
    print(" var obj2 is located at address: \($0)")
}
obj2 = Test() //Create new instance.
withUnsafePointer(to: &obj2) {
    print(" var obj2 is still located at address: \($0)")
}

输出：

 var obj1 is located at address: 0x00000001003e4398
 var obj2 is located at address: 0x00000001003e43a0
 var obj2 is still located at address: 0x00000001003e43a0

 ObjectIdentifier of obj1 is ObjectIdentifier(0x0000000100e04a80)
 ObjectIdentifier of obj2 is ObjectIdentifier(0x0000000100e04a80)
 ObjectIdentifier of obj2 is now ObjectIdentifier(0x0000000100e075f0)

Address of obj1 = 0000000100E04A50
Address of obj2 = 0000000100E049E0

如果要比较

obj1

和

obj2

中包含的引用，使用

ObjectIdentifier

将是一种简单的方法：

obj2 = Test.sharedInstance
print(" ObjectIdentifier of obj1 is \(ObjectIdentifier(obj1))")
print(" ObjectIdentifier of obj2 is \(ObjectIdentifier(obj2))")
obj2 = Test()
print(" ObjectIdentifier of obj2 is now \(ObjectIdentifier(obj2))")

输出：

 var obj1 is located at address: 0x00000001003e4398
 var obj2 is located at address: 0x00000001003e43a0
 var obj2 is still located at address: 0x00000001003e43a0

 ObjectIdentifier of obj1 is ObjectIdentifier(0x0000000100e04a80)
 ObjectIdentifier of obj2 is ObjectIdentifier(0x0000000100e04a80)
 ObjectIdentifier of obj2 is now ObjectIdentifier(0x0000000100e075f0)

Address of obj1 = 0000000100E04A50
Address of obj2 = 0000000100E049E0

或者，您可以将引用转换为不透明指针，然后再转换为int，如下所示：

let addrInt1 = Int(bitPattern: Unmanaged.passRetained(obj1).toOpaque())
print("Address of obj1 = \(String(format: "%016lX", addrInt1))")
let addrInt2 = Int(bitPattern: Unmanaged.passRetained(obj2).toOpaque())
print("Address of obj2 = \(String(format: "%016lX", addrInt2))")

输出：

 var obj1 is located at address: 0x00000001003e4398
 var obj2 is located at address: 0x00000001003e43a0
 var obj2 is still located at address: 0x00000001003e43a0

 ObjectIdentifier of obj1 is ObjectIdentifier(0x0000000100e04a80)
 ObjectIdentifier of obj2 is ObjectIdentifier(0x0000000100e04a80)
 ObjectIdentifier of obj2 is now ObjectIdentifier(0x0000000100e075f0)

Address of obj1 = 0000000100E04A50
Address of obj2 = 0000000100E049E0

---

您的代码显示两个变量的地址，

obj1

和

obj2

import Foundation

class Test {
    static let sharedInstance = Test()
    init() {} //Make initializer accessible for testing.
}

var obj1 = Test.sharedInstance
var obj2 = Test.sharedInstance

withUnsafePointer(to: &obj1) {
    print(" var obj1 is located at address: \($0)")
}
withUnsafePointer(to: &obj2) {
    print(" var obj2 is located at address: \($0)")
}
obj2 = Test() //Create new instance.
withUnsafePointer(to: &obj2) {
    print(" var obj2 is still located at address: \($0)")
}

输出：

 var obj1 is located at address: 0x00000001003e4398
 var obj2 is located at address: 0x00000001003e43a0
 var obj2 is still located at address: 0x00000001003e43a0

 ObjectIdentifier of obj1 is ObjectIdentifier(0x0000000100e04a80)
 ObjectIdentifier of obj2 is ObjectIdentifier(0x0000000100e04a80)
 ObjectIdentifier of obj2 is now ObjectIdentifier(0x0000000100e075f0)

Address of obj1 = 0000000100E04A50
Address of obj2 = 0000000100E049E0

如果要比较

obj1

和

obj2

中包含的引用，使用

ObjectIdentifier

将是一种简单的方法：

obj2 = Test.sharedInstance
print(" ObjectIdentifier of obj1 is \(ObjectIdentifier(obj1))")
print(" ObjectIdentifier of obj2 is \(ObjectIdentifier(obj2))")
obj2 = Test()
print(" ObjectIdentifier of obj2 is now \(ObjectIdentifier(obj2))")

输出：

 var obj1 is located at address: 0x00000001003e4398
 var obj2 is located at address: 0x00000001003e43a0
 var obj2 is still located at address: 0x00000001003e43a0

 ObjectIdentifier of obj1 is ObjectIdentifier(0x0000000100e04a80)
 ObjectIdentifier of obj2 is ObjectIdentifier(0x0000000100e04a80)
 ObjectIdentifier of obj2 is now ObjectIdentifier(0x0000000100e075f0)

Address of obj1 = 0000000100E04A50
Address of obj2 = 0000000100E049E0

或者，您可以将引用转换为不透明指针，然后再转换为int，如下所示：

let addrInt1 = Int(bitPattern: Unmanaged.passRetained(obj1).toOpaque())
print("Address of obj1 = \(String(format: "%016lX", addrInt1))")
let addrInt2 = Int(bitPattern: Unmanaged.passRetained(obj2).toOpaque())
print("Address of obj2 = \(String(format: "%016lX", addrInt2))")

输出：

 var obj1 is located at address: 0x00000001003e4398
 var obj2 is located at address: 0x00000001003e43a0
 var obj2 is still located at address: 0x00000001003e43a0

 ObjectIdentifier of obj1 is ObjectIdentifier(0x0000000100e04a80)
 ObjectIdentifier of obj2 is ObjectIdentifier(0x0000000100e04a80)
 ObjectIdentifier of obj2 is now ObjectIdentifier(0x0000000100e075f0)

Address of obj1 = 0000000100E04A50
Address of obj2 = 0000000100E049E0

---

我知道了，非常感谢！我知道了，非常感谢！