Re: GObject and floating reference count

[Tristan Van Berkom <tvb gnome org>]

Hannes Mayr wrote:
> Hello,
>
> I'm a little bit confused about the explanation of the floating 
> reference count.
>
> The documentation says about GObject:
> "The initial reference a GObject is created with is flagged as a 
> floating reference. This means that it is not specifically claimed to be 
> "owned" by any code portion."
> http://developer.gnome.org/doc/API/2.0/gobject/gobject-The-Base-Object-Type.html#floating-ref 
>
>
> And about GtkObject:
> "The most interesting difference between GtkObject and GObject is the 
> "floating" reference count. A GObject is created with a reference count 
> of 1, owned by the creator of the GObject. (The owner of a reference is 
> the code section that has the right to call g_object_unref() in order to 
> remove that reference.) A GtkObject is created with a reference count of 
> 1 also, but it isn't owned by anyone;"
> http://developer.gnome.org/doc/API/2.0/gtk/GtkObject.html
>
> So, the part of GtkObject says GObject is owned by the creator and the 
> docs about GObject itself says it isn't owned by anyone (until 
> g_object_sink() is called).
>
> Who is wrong here? Or maybe I unterstood something wrong...

This is a whole new can of bugs waiting to spill, the answer to your
question is that both are created floating in GTK+-2.10, before that
GObjects were never floating and floating widgets were the main incentive
to keep GtkObject around.

So the docs need love.

> Why I'm asking is because I don't know exactly if the following code 
> needs a g_object_unref of the GtkListStore, which has as parent GObject 
> and not GtkObject.
>
> Code:
>   GtkListStore *store;
>   store = gtk_list_store_new(N_EDIT_TV_COLUMNS,
>     G_TYPE_INT,
>     G_TYPE_STRING,
>     G_TYPE_STRING,
>     G_TYPE_INT
>   );
>
>   gtk_tree_view_set_model(GTK_TREE_VIEW(tview), GTK_TREE_MODEL(store));
>
>   // is this needed??
>   g_object_unref(G_OBJECT(store));

That is a damned good question, in my opinion it should be absolutely
nescisary to unref it; because my opinion is that only GtkWidgets when
added to GtkContainers should be "sunk", if we dont have a clear rule
like that; how will anyone ever know what to unref ?

/me obstinatly leaves it to someone else to open up gtktreeview.c to find out

Cheers,
                     -Tristan