Re: chaining OBJECT_new() functions?

[Roger Leigh <rleigh whinlatter ukfsn org>]

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Ben Johnson <ben blarg net> writes:

> I made a class that defines several _new() functions, which take various
> parameters.  I now want to subclass from this and keep my various _new()
> functions with more or less the same parameters, and I want the behavior
> to stay the same too.  I don't see anything in the documentation about
> how to do it though.  anyone know?

What about a factory function which allows one to choose the specific
derived type.  For example,

GtkGroupedToggle *
gtk_grouped_toggle_new_from_widget (GType               group_toggle_type,
                                    GtkGroupedToggle   *group)
     GtkGroupedToggle *new_toggle = NULL;

     g_return_val_if_fail(g_type_is_a(group_toggle_type,
                                      GTK_TYPE_GROUPED_TOGGLE) == TRUE), NULL);

     new_toggle = g_object_new (type, NULL);
     if( new_toggle )
         new_toggle = gtk_grouped_toggle_add_to_list (new_toggle, group);

     return GTK_WIDGET(new_toggle);
}

You now don't need any _new() functions for derived types.

Also, isn't it bad practice to have arguments to a _new() function
which are not construction parameters?  Wouldn't it be better to add
to group manually, or have g_object_new in a method of the container
so it can't exist independently?


Regards,
Roger

- -- 
Roger Leigh
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