[glibmm/wip/dboles/Binding-Issue#62: 6/7] Binding: Clarify need to hold ref, poss empty objs

[Daniel Boles <dboles src gnome org>]

commit 9682c4d79c200408d18336a84f3312f19738baf1
Author: Daniel Boles <dboles src gmail com>
Date:   Mon Nov 18 11:22:34 2019 +0000

    Binding: Clarify need to hold ref, poss empty objs
    
    and move the documentation on lifetime away from bind_property_value()
    up to the class description/intro.
    
    https://gitlab.gnome.org/GNOME/glibmm/issues/62

 glib/src/binding.hg | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)
---
diff --git a/glib/src/binding.hg b/glib/src/binding.hg
index c6849e17..f88e254e 100644
--- a/glib/src/binding.hg
+++ b/glib/src/binding.hg
@@ -90,10 +90,13 @@ namespace Glib
  * various ways of blocking a signal emission, like Glib::SignalProxyNormal::emission_stop()
  * or g_signal_handler_block().
  *
- * A binding will be severed, and the resources it allocates freed, whenever
- * either one of the Glib::ObjectBase instances it refers to is deleted,
- * when unbind() is called, or when the Glib::Binding instance loses
- * its last reference.
+ * The binding between properties is broken, and its resources freed, when the
+ * Glib::Binding loses its last Glib::RefPtr, the source or target object is
+ * deleted, or unbind() is called. If a Glib::RefPtr to the Glib::Binding
+ * remains after the binding is broken another way, Glib::Binding::get_source()
+ * and Glib::Binding::get_target() return an empty Glib::RefPtr. So, you must
+ * keep a Glib::RefPtr to the Glib::Binding for as long as you want it to bind,
+ * but doing that does not guarantee the source/target are still alive or bound.
  *
  * @newin{2,44}
  */
@@ -148,10 +151,6 @@ public:
    * will be updated as well. The @a transform_from function is only used in case
    * of bidirectional bindings, otherwise it will be ignored.
    *
-   * The binding will automatically be removed when either the source or the
-   * target instance is deleted. To remove the binding without affecting the
-   * source and the target you can call unbind() on the returned Binding instance.
-   *
    * A Glib::ObjectBase instance can have multiple bindings.
    *
    * If you supply transformation functions, it is usually easier to use one of the