Re: GtkTreeView

[Jonathan Blandford <jrb redhat com>]

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.

[ 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