[glib] gcancellable: Clarify that GSources hold references to GCancellables

[Philip Withnall <pwithnall src gnome org>]

commit 203fe3b8a8817da8e1ec771e2ebd15c747653158
Author: Philip Withnall <philip withnall collabora co uk>
Date:   Wed Sep 24 14:06:02 2014 +0100

    gcancellable: Clarify that GSources hold references to GCancellables
    
    Clarify in the documentation that a GSource created with
    g_cancellable_source_new() must be explicitly removed from its
    GMainContext before the GCancellable can be finalised.
    
    This could be a common way of leaking GCancellables.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=737259

 gio/gcancellable.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gio/gcancellable.c b/gio/gcancellable.c
index 800e8f3..258b88d 100644
--- a/gio/gcancellable.c
+++ b/gio/gcancellable.c
@@ -722,6 +722,8 @@ static GSourceFuncs cancellable_source_funcs =
  * For convenience, you can call this with a %NULL #GCancellable,
  * in which case the source will never trigger.
  *
+ * The new #GSource will hold a reference to the #GCancellable.
+ *
  * Returns: (transfer full): the new #GSource.
  *
  * Since: 2.28