如何快速获取IP地址

在讨论中发现，OP需要Mac上的接口地址，而不是我最初想的那样在iOS设备上。问题中引用的代码将检查接口名称“en0”，它是iPhone上的WiFi接口。在Mac上，改为检查任何“正在运行”的界面更有意义。因此，我重写了答案。现在，它是“检测任何连接的网络”中代码的快速翻译 。

getifaddrs()

<ifaddrs.h>

#include <ifaddrs.h>

以下函数返回一个数组，其中包含所有本地“正在运行的”网络接口的名称。

func getIFAddresses() -> [String] {    var addresses = [String]()    // Get list of all interfaces on the local machine:    var ifaddr : UnsafeMutablePointer<ifaddrs> = nil    if getifaddrs(&ifaddr) == 0 {        // For each interface ...        var ptr = ifaddr        while ptr != nil { defer { ptr = ptr.memory.ifa_next } let flags = Int32(ptr.memory.ifa_flags) let addr = ptr.memory.ifa_addr.memory // Check for running IPv4, IPv6 interfaces. Skip the loopback interface. if (flags & (IFF_UP|IFF_RUNNING|IFF_LOOPBACK)) == (IFF_UP|IFF_RUNNING) {     if addr.sa_family == UInt8(AF_INET) || addr.sa_family == UInt8(AF_INET6) {         // Convert interface address to a human readable string:         var hostname = [CChar](count: Int(NI_MAXHOST), repeatedValue: 0)         if (getnameinfo(ptr.memory.ifa_addr, socklen_t(addr.sa_len), &hostname, socklen_t(hostname.count),  nil, socklen_t(0), NI_NUMERICHOST) == 0) {  if let address = String.fromCString(hostname) {      addresses.append(address)  }         }     } }        }        freeifaddrs(ifaddr)    }    return addresses}

Swift 3的更新： 除了 对Swift 3 的许多更改采用代码之外 ，对所有接口进行迭代现在还可以使用新的通用

sequence()

func getIFAddresses() -> [String] {    var addresses = [String]()    // Get list of all interfaces on the local machine:    var ifaddr : UnsafeMutablePointer<ifaddrs>?    guard getifaddrs(&ifaddr) == 0 else { return [] }    guard let firstAddr = ifaddr else { return [] }    // For each interface ...    for ptr in sequence(first: firstAddr, next: { $0.pointee.ifa_next }) {        let flags = Int32(ptr.pointee.ifa_flags)        let addr = ptr.pointee.ifa_addr.pointee        // Check for running IPv4, IPv6 interfaces. Skip the loopback interface.        if (flags & (IFF_UP|IFF_RUNNING|IFF_LOOPBACK)) == (IFF_UP|IFF_RUNNING) { if addr.sa_family == UInt8(AF_INET) || addr.sa_family == UInt8(AF_INET6) {     // Convert interface address to a human readable string:     var hostname = [CChar](repeating: 0, count: Int(NI_MAXHOST))     if (getnameinfo(ptr.pointee.ifa_addr, socklen_t(addr.sa_len), &hostname, socklen_t(hostname.count),          nil, socklen_t(0), NI_NUMERICHOST) == 0) {         let address = String(cString: hostname)         addresses.append(address)     } }        }    }    freeifaddrs(ifaddr)    return addresses}