[gtk+] GtkBox: The center widget can be NULL

[Timm Bäder <baedert src gnome org>]

commit 88b4955fd92c5d3e8d351adac56199b5999fc9d8
Author: Timm Bäder <mail baedert org>
Date:   Tue Dec 1 13:36:21 2015 +0100

    GtkBox: The center widget can be NULL
    
    Propagates to GtkActionBar.

 gtk/gtkactionbar.c |    2 +-
 gtk/gtkbox.c       |    3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkactionbar.c b/gtk/gtkactionbar.c
index dd8aaf4..0d3f93b 100644
--- a/gtk/gtkactionbar.c
+++ b/gtk/gtkactionbar.c
@@ -359,7 +359,7 @@ gtk_action_bar_set_center_widget (GtkActionBar *action_bar,
  *
  * Retrieves the center bar widget of the bar.
  *
- * Returns: (transfer none): the center #GtkWidget.
+ * Returns: (transfer none) (nullable): the center #GtkWidget or %NULL.
  *
  * Since: 3.12
  */
diff --git a/gtk/gtkbox.c b/gtk/gtkbox.c
index 945f928..51eb5d4 100644
--- a/gtk/gtkbox.c
+++ b/gtk/gtkbox.c
@@ -2655,7 +2655,8 @@ gtk_box_set_center_widget (GtkBox    *box,
  *
  * Retrieves the center widget of the box.
  *
- * Returns: (transfer none): the center widget
+ * Returns: (transfer none) (nullable): the center widget
+ *   or %NULL in case no center widget is set.
  *
  * Since: 3.12
  */