A #GstPoll keeps track of file descriptors much like fd_set (used with select ()) or a struct pollfd array (used with poll ()). Once created with gst.poll.Poll.new_, the set can be used to wait for file descriptors to be readable and/or writable. It is possible to make this wait be controlled by specifying true for the @controllable flag when creating the set (or later calling gst.poll.Poll.setControllable).