[Vala] Allowable to add user data to callback?

[bsquared <bwcode4u gmail com>]

Hello,

I am trying to follow a c example for pulse audio and in it's setting
of a callback it adds a userdata parameter.

Can I do the same with vala? or should I use a field to store the
userdata from the callback?

The example [1]  is approximating this...

/////////// 8< from  libpulse.vapi ////////////
public delegate void NotifyCb(Context c);
public void set_state_callback(NotifyCb? cb = null);
///////////////////////////////////////////////////////////

private void pa_set_state_cb(Context ctx, void* userdata) {
  Context.State state = ctx.get_state();
  switch (state) {
    case e: *pa_ready = 2; break;
    case x: *pa_ready = 1; break;
    case y:
    case z:
    default: *pa_ready = 0; break;
  }
}

public int some_method() {
  int pa_ready = 0;
  PulseAudio.Context context = new PulseAudio.Context();
  context.set_state_callback(this.pa_set_state_cb, &pa_ready);
  int state = 0;
  context.connect();

  while (true) {
    if (pa_ready == 0} {}
    if (pa_ready == 1) {}
    if (pa_ready == 2) {}
  }
}


-- 
Regards,
-Brian

[1] - http://www.ypass.net/blog/2009/10/pulseaudio-an-async-example-to-get-device-lists/