主程式：
if let addr = getWiFiAddress() {
let ip_addr_array = addr.components(separatedBy: “.”)
self.IpAddressFirst2 = ip_addr_array[0] + “.” + ip_addr_array[1]
print(“ip address:” + IpAddressFirst2)
}
副程式：
// Return IP address of WiFi interface (en0) as a String, or `nil`
func getWiFiAddress() -> String? {
var address : String?
// Get list of all interfaces on the local machine:
var ifaddr : UnsafeMutablePointer<ifaddrs>?
guard getifaddrs(&ifaddr) == 0 else { return nil }
guard let firstAddr = ifaddr else { return nil }
// For each interface …
for ifptr in sequence(first: firstAddr, next: { $0.pointee.ifa_next }) {
let interface = ifptr.pointee
// Check for IPv4 or IPv6 interface:
let addrFamily = interface.ifa_addr.pointee.sa_family
if addrFamily == UInt8(AF_INET) || addrFamily == UInt8(AF_INET6) {
// Check interface name:
let name = String(cString: interface.ifa_name)
if name == “en0” {
// Convert interface address to a human readable string:
var hostname = [CChar](repeating: 0, count: Int(NI_MAXHOST))
getnameinfo(interface.ifa_addr, socklen_t(interface.ifa_addr.pointee.sa_len),
&hostname, socklen_t(hostname.count),
nil, socklen_t(0), NI_NUMERICHOST)
address = String(cString: hostname)
}
}
}
freeifaddrs(ifaddr)
return address
}