Re: GtkTreeView

[Tim Janik <timj gtk org>]

On 13 Aug 2001, Jonathan Blandford wrote:

> Tim Janik <timj gtk org> writes:
> 
> > On 13 Aug 2001, David Bryant wrote:
> > 
> > > GValue value;
> > > memset(&value, 0, sizeof(value));	// not sure about this
> > > gtk_tree_model_get_value(model, iter, 2, &value);
> > > gpointer user_data = value.data[0].v_pointer;	// is this "right" ?
> > 
> > jonathan, if this is really possible with the tree model API, then it's
> > fundamentally broken. you should not accept a 0-type-value from the user and
> > g_value_init() it with a type. GValues should always be passed around
> > properly type initialized, i.e. treemodel should assert that the type
> > of the value to get is_a
> > G_VALUE_TYPE (value_passed_to_gtk_tree_model_get_value).
> 
> I think it should indeed handle both.  Currently, it expects a zeroed
> out GValue, but certainly should allow a type to be passed in so it can
> do a transform, if necessary.  However, if I don't allow an
> uninitialized value, then every single instance that wants a value will
> have to do:
> 
> GValue value = {0, };
> g_value_init (&value, gtk_tree_model_get_column_type (model, col));
> gtk_tree_model_get_value (model, iter, &value, col);
> 
> I'd rather let people skip that second step, if possible.

well, as you say, people are probably going to use gtk_tree_model_get() anyways.
the main purpose in _get_value() variants are for LB or builder backends,
so a bit additional work doesn't do much harmn here.
and i'd rather keep these APIs consistent.

> [ Actually, I think most people will be doing a:
>   gtk_tree_model_get (model, iiter, col, &my_string, -1);
>   anyway, so this probably isn't that important. ]
> 
> 
> Thanks,
> -Jonathan
> 
> 

---
ciaoTJ