     // how to refer to self?
   
   public init() {
+#if os(Linux) // no sin_len on Linux
+#else
     sin_len    = sockaddr_in.size
+#endif
     sin_family = sa_family_t(sockaddr_in.domain)
     sin_port   = 0
     sin_addr   = INADDR_ANY

      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 0, 0, 0, 0, 0, 0, 0
    );
  }
  
  public var len: __uint8_t {

    if ai_family != AF_UNSPEC { s += sa_family_t(ai_family).description }
    switch ai_socktype {
      case 0:           break
      case sys_SOCK_STREAM: s += " stream"
      case sys_SOCK_DGRAM:  s += " datagram"
      default:              s += " type[\(ai_socktype)]"
    }
    
    if let cn = canonicalName {
