Document how to unset attributes

Unsetting won't work on all attributes. Currently, only
metadata attributes are supported.

https://bugzilla.gnome.org/show_bug.cgi?id=620423

diff --git a/gio/gfile.c b/gio/gfile.c
index a5d00fe..c67dab9 100644 (file)
--- a/gio/gfile.c
+++ b/gio/gfile.c
@@ -3828,6 +3828,9 @@ g_file_query_writable_namespaces (GFile         *file,
  * @error: a #GError, or %NULL
  * 
  * Sets an attribute in the file with attribute name @attribute to @value.
+ *
+ * Some attributes can be unset by setting @attribute to
+ * %G_FILE_ATTRIBUTE_TYPE_INVALID and @value to %NULL.
  * 
  * If @cancellable is not %NULL, then the operation can be cancelled by
  * triggering the cancellable object from another thread. If the operation