在Swift中声明自引用指针

Question

这个Obj-C代码的快速等价是什么？

我猜错了CMutableVoidPointer

static void *CapturingStillImageContext = &CapturingStillImageContext;

Answer 1

从Beta 3开始，

CMutableVoidPointer不再可用.Theres UnsafePointer和ConstUnsafePointer - 您可以这样声明：

let CapturingStillImageContext = UnsafePointer<()>()

Answer 2

可能是这样的：

var CapturingStillImageContext: COpaquePointer = nil
withUnsafePointer(&CapturingStillImageContext) {
    CapturingStillImageContext = COpaquePointer($0) }

Answer 3

我一直在使用这种技术，但找到更优雅的解决方案会很好：

var SelfReferencingKey = initialize_SelfReferencingKey()

func initialize_SelfReferencingKey() -> UnsafePointer<()> {
    return withUnsafePointer(&SelfReferencingKey, { UnsafePointer($0) } )
}