docs: Document gtk_recent_filter_filter() requirements

gtk_recent_filter_filter() needs the contains bitfield to be set, but
this only mentions that the other fields are required.

https://bugzilla.gnome.org/show_bug.cgi?id=726900

diff --git a/gtk/gtkrecentfilter.c b/gtk/gtkrecentfilter.c
index 8b4f2f7c3a55bc1aebce35df82b1d901446fef7e..a346e807e558e29c9b5aefa64a9f2bf56cabed90 100644 (file)
--- a/gtk/gtkrecentfilter.c
+++ b/gtk/gtkrecentfilter.c
@@ -695,7 +695,9 @@ gtk_recent_filter_add_custom (GtkRecentFilter      *filter,
  *
  * Tests whether a file should be displayed according to @filter.
  * The #GtkRecentFilterInfo @filter_info should include
- * the fields returned from gtk_recent_filter_get_needed().
+ * the fields returned from gtk_recent_filter_get_needed(), and
+ * must set the #GtkRecentFilterInfo.contains field of @filter_info
+ * to indicate which fields have been set.
  *
  * This function will not typically be used by applications; it
  * is intended principally for use in the implementation of