[aravis] camera: allow null parameters for stream callback and user_data.

[Emmanuel Pacaud <emmanuel src gnome org>]

commit fce84886741565536e3e15dc65452dcbe203d0cc
Author: Emmanuel Pacaud <emmanuel gnome org>
Date:   Thu Apr 21 22:03:26 2011 +0200

    camera: allow null parameters for stream callback and user_data.

 src/arvcamera.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/arvcamera.c b/src/arvcamera.c
index ed74e6b..917c786 100644
--- a/src/arvcamera.c
+++ b/src/arvcamera.c
@@ -77,8 +77,8 @@ struct _ArvCameraPrivate {
 /**
  * arv_camera_create_stream:
  * @camera: a #ArvCamera
- * @callback: (scope call): a frame processing callback
- * @user_data: (closure) user data for @callback
+ * @callback: (scope call) (allow-none): a frame processing callback
+ * @user_data: (closure) (allow-none): user data for @callback
  * Return value: (transfer full): a new #ArvStream.
  *
  * Creates a new #ArvStream for video stream handling. See