GSocketConnectable

Objects that describe one or more potential socket endpoints implement gio.socket_connectable.SocketConnectable. Callers can then use gio.socket_connectable.SocketConnectable.enumerate to get a gio.socket_address_enumerator.SocketAddressEnumerator to try out each socket address in turn until one succeeds, as shown in the sample code below.

MyConnectionType *
connect_to_host (const char    *hostname,
                 guint16        port,
                 GCancellable  *cancellable,
                 GError       **error)
{
  MyConnection *conn = NULL;
  GSocketConnectable *addr;
  GSocketAddressEnumerator *enumerator;
  GSocketAddress *sockaddr;
  GError *conn_error = NULL;

  addr = g_network_address_new (hostname, port);
  enumerator = g_socket_connectable_enumerate (addr);
  g_object_unref (addr);

  // Try each sockaddr until we succeed. Record the first connection error,
  // but not any further ones (since they'll probably be basically the same
  // as the first).
  while (!conn && (sockaddr = g_socket_address_enumerator_next (enumerator, cancellable, error))
    {
      conn = connect_to_sockaddr (sockaddr, conn_error ? NULL : &conn_error);
      g_object_unref (sockaddr);
    }
  g_object_unref (enumerator);

  if (conn)
    {
      if (conn_error)
        {
          // We couldn't connect to the first address, but we succeeded
          // in connecting to a later address.
          g_error_free (conn_error);
        }
      return conn;
    }
  else if (error)
    {
      /// Either initial lookup failed, or else the caller cancelled us.
      if (conn_error)
        g_error_free (conn_error);
      return NULL;
    }
  else
    {
      g_error_propagate (error, conn_error);
      return NULL;
    }
}