unsafe-pointers

I'm attempting to call SecItemCopyMatching in my keychain utility class in order to get data out of the keychain, yet I'm running into a problem with getting the result argument, UnsafeMutablePointer<CFTypeRef?> . The original statement (in Swift 2, before migrating to Swift 3) was // query is a dictionary of [String : AnyObject] var result: Data? let status = withUnsafeMutablePointer(to: &result) { SecItemCopyMatching(query as CFDictionary, UnsafeMutablePointer($0)) } But in Swift 3, you are now required to call .withMemoryRebound in order to view memory. Based on what Xcode tells you to do,

I want to call the Posix socket functions socket and bind from Swift. socket is pretty easy—it takes Int32 s, but bind is causing a problem, because I have a sockaddr_in pointer, but it wants a sockaddr pointer. In C, this would be a cast, like: bind(sock, (struct sockaddr *)&sockAddress, sizeof(sockAddress)) Here's an attempt in Swift: let sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP) var sockAddress = sockaddr_in() bind(sock, &sockAddress, UInt32(MemoryLayout<sockaddr_in>.size)) The bind line fails to compile with: cannot convert value of type 'sockaddr_in' to expected argument type

I'd like to create an extension for UnsafeMutablePointer that only affects UnsafeMutablePointer<UInt8> ... I understand that these instructions are pertinent, but I'm not sure how: When you extend a generic type, you do not provide a type parameter list as part of the extension’s definition. Instead, the type parameter list from the original type definition is available within the body of the extension, and the original type parameter names are used to refer to the type parameters from the original definition. Basically, I'm trying to use this method: func toSwift(length: Int) -> [Int] { var

I'm looking for the simplest ways to achieve reasonable C interoperability in Swift, and my current block is converting an UnsafePointer<Int8> (which was a const char * ), into an [Int8] array. Currently, I have a naïve algorithm that can take an UnsafePointer and a number of bytes and converts it to an array, element by element: func convert(length: Int, data: UnsafePointer<Int8>) { let buffer = UnsafeBufferPointer(start: data, count: length); var arr: [Int8] = [Int8]() for (var i = 0; i < length; i++) { arr.append(buffer[i]) } } The loop itself can be sped up by using arr.reserveCapacity

My code snipet as follows …: let defaultRouteReachability = withUnsafePointer(to: &zeroAddress) { SCNetworkReachabilityCreateWithAddress(nil, UnsafePointer($0)) } … does no longer compile with the following error which I don't understand: "'init' is unavailable: use 'withMemoryRebound(to:capacity:_)' to temporarily view memory as another layout-compatible type." What to do to fix it? From the Release Notes of Xcode 8 beta 6: An Unsafe[Mutable]RawPointer type has been introduced, replacing Unsafe[Mutable]Pointer<Void> . Conversion from UnsafePointer<T> to UnsafePointer<U> has been disallowed.

I'm new to swift and I have some difficulties to deal with pointers of unmanaged CFString (or NSString). I'm working on a CoreMIDI project that implies usage of UnsafeMutablePointer?> as you can see in this function : func MIDIObjectGetStringProperty(_ obj: MIDIObjectRef, _ propertyID: CFString!, _ str: UnsafeMutablePointer<Unmanaged<CFString>?>) -> OSStatus My problem is that I want to allocate a buffer to receive the content of the property (_str) then call the function above, and finally print the content in the console by using println. At the moment I wrote this : // Get the first midi