RE: How to orderly empty a tree view without memory leakage?

[martyn 2 russell bt com]

> What am I supposed to do in order to cleanly free the 
> contents of a tree
> view without memory leakage in GTK+ 2.2.? I have a tree view 
> which is to
> be refilled with completely different data when the user of my program
> selects different data sources.

The first thing to remember is GTK takes a copy of all the data you pass it,
hence, you are expected to free all memory you create, NOT all memory GTK
creates.

> My approach was to
> 1. gtk_tree_view_remove_column (tv, column) for every
>    gtk_tree_view_get_column (tv, 0) there is,
> 3. gtk_tree_view_set_model (tv, NULL) to free(?) the existing model.

The easiest way to do this is to use the gtk_tree_store_clear() or
gtk_list_store_clear() function.  This removes the data.  See here:
http://developer.gnome.org/doc/API/2.0/gtk/GtkListStore.html#gtk-list-store-
clear

Adding and removing columns is only necessary if you change the columns
based on the data being displayed.  If the data is similar, it is probably
best to hide/show columns as necessary.  If the data is completely
different, I would suggest having two different treeviews and hiding/showing
which ever one is required at the time.

> However, there is still a noticeable increase of memory 
> consumption by the
> program, each time when I refill the tree view. I then added step 2:
>
> 2. gtk_tree_view_get_model (tv) and g_object_unref () it!

When you use gtk_tree_store_new() or gtk_list_store_new(), there are two
references on the store.  One is GTKs reference and the other is for you
(although a quick look at the gtk_list_store_new() API documentation does
not state this and I think it should).

As the demo (gtk-demo) demonstrates, you should free your copy if you wish
to no longer keep it around. - This is usually after creation.

>   g_object_unref'ing the model reproducible for some of you 
> or am I wrong?
> - Am I really supposed to manually g_object_unref () the model?
> - Should I manually g_object_unref () more objects, for instance the
>   columns, before removing them or is it a bug in GTK+ 2.2 that models
>   have to be unref'd manually to prevent memory leaks?

See the documentation.  It *SHOULD* state those objects which should be
unreferences, all others should not.  If there is something that is not
documented that should be unreferenced, it is a bug in GTKs documentation
and should be reported to http://bugzilla.gnome.org

> - What about cell renderers? Are they (supposed to be) unref'd / freed
>   implicitly when all columns are removed or should I (try 
> to) unref them?

No, not as far as I am aware.

Regards,
Martyn