将一个Swift结构体转换为UnsafeMutablePointer< Void> [英] Cast a Swift struct to UnsafeMutablePointer<Void>

问题描述

有一种方法可以将Swift结构体的地址转换为void UnsafeMutablePointer？

我没有成功尝试过：

Is there a way to cast a Swift struct's address to a void UnsafeMutablePointer?
I tried this without success:

struct TheStruct {
    var a:Int = 0
}

var myStruct = TheStruct()
var address = UnsafeMutablePointer<Void>(&myStruct)

谢谢！

strong> EDIT：上下文

我实际上试图将学习CoreAudio的第一个例子移植到Swift。

这是我的到目前为止：

the context
I am actually trying to port to Swift the first example in Learning CoreAudio.
This is what I have done until now:

func myAQInputCallback(inUserData:UnsafeMutablePointer<Void>,
    inQueue:AudioQueueRef,
    inBuffer:AudioQueueBufferRef,
    inStartTime:UnsafePointer<AudioTimeStamp>,
    inNumPackets:UInt32,
    inPacketDesc:UnsafePointer<AudioStreamPacketDescription>)
 { }

struct MyRecorder {
    var recordFile:     AudioFileID = AudioFileID()
    var recordPacket:   Int64       = 0
    var running:        Boolean     = 0
}

var queue:AudioQueueRef = AudioQueueRef()
AudioQueueNewInput(&asbd,
    myAQInputCallback,
    &recorder,  // <- this is where I *think* a void pointer is demanded
    nil,
    nil,
    UInt32(0),
    &queue)

$ b b

我正在努力留在Swift，但如果这证明是一个问题而不是一个优势，我将最终链接到一个C函数。

I am doing efforts to stay in Swift, but if this turns out to be more a problem than an advantage, I will end up linking to a C function.

编辑：底线

如果您遇到此问题，因为您试图在Swift中使用CoreAudio的AudioQueue ... 别。 （阅读注释的细节）

bottome line
If you came to this question because you are trying to use a CoreAudio's AudioQueue in Swift... don't. (read the comments for details)

推荐答案

据我所知，最简单的方法是：

As far as I know, the shortest way is:

var myStruct = TheStruct()
var address = withUnsafeMutablePointer(&myStruct) {UnsafeMutablePointer<Void>($0)}

但是，为什么你需要这个？如果您希望将其作为参数传递，则可以（并且应该）：

But, why you need this? If you want pass it as a parameter, you can (and should):

func foo(arg:UnsafeMutablePointer<Void>) {
    //...
}

var myStruct = TheStruct()
foo(&myStruct)

这篇关于将一个Swift结构体转换为UnsafeMutablePointer< Void>的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！