Re: destroing data attached to a type (qdata)

["Brian J. Tarricone" <bjt23 cornell edu>]

Stefan Kost wrote:
> hi,
>
> I have an interface, where I share some data between the instances.  
> the data is created on first access. Now I also would like to release  
> it when the last instance goes.
> problem 1: base_finalize() is not called for static types
>
> I thought that I could do some own ref-counting and then do  
> g_object_weak_ref on the instances to decrement the ref-count.
> problem 2: There is nothing in the GTypeInfo for an iface that is  
> called for each new instance (using instance_init causes  
> g_type_register_static (G_TYPE_INTERFACE,...) to fail as one does not  
> really instantiate the iface, but the type that implements it).
> Any ideas?
I don't think this method will work -- I'm pretty sure GTypes (esp 
static types) never get destroyed, even after their last instance is 
destroyed.
Probably your best bet would be to create your shared data in the 
instance_init function on first run (just make it a static global var in 
the file), and then refcount it.  When your last instance is destroyed, 
the refcount of the shared data drops to zero and you can destroy it.
        -brian