Re: Must widgets stay in context?

[Bob Caryl <bob fis-cal com>]

There is nothing weird about the non-managed widget's destructor not
running; because it doesn't ever go out of scope, is not being called. 
It represents a memory leak.

Bob

pks timing com wrote:

>R. Douglas Barbieri writes:
> > 
> > A question regarding this: does GTK have some sort of
> > garbage-collection management, or are all of the "manage()"ed widgets
> > finally freed at runtime?
>
>I believe a managed widget is destroyed when it's container is.  This
>is a pretty contrived example but shows that only the managed is destroyed
>when the box holding it is ... 
>
>one weird thing to note that no output is produced by the unmanaged
>label's destructor, even when the application terminates in response
>to the window being closed ...
>
>
>#include <gtkmm/window.h>
>#include <gtkmm/label.h>
>#include <gtkmm/box.h>
>#include <gtkmm/main.h>
>#include <gtkmm/button.h>
>#include <iostream>
>
>Gtk::HBox *box1, *box2;
>
>class Lbl : public Gtk::Label
>{
>public:
>
>    Lbl(const Glib::ustring &caption)
>        : Gtk::Label(caption)
>    {
>    }
>
>    virtual ~Lbl()
>    {
>        std::cerr << get_text() << " is biting the dust\n";
>    }
>};
>
>void DeleteLabelBoxes()
>{
>    std::cerr << "deleting both label boxes\n";
>    delete box1;
>    delete box2;
>}
>
>int
>main(int argc, char *argv[])
>{
>    Gtk::Main kit(argc, argv);
>
>    Gtk::Window win;
>    Gtk::VBox vbox(true, 3);
>
>    box1 = new Gtk::HBox(true, 0);
>    Lbl *l1 = Gtk::manage(new Lbl("managed label"));
>    box1->pack_start(*l1, Gtk::PACK_EXPAND_WIDGET);
>
>    box2 = new Gtk::HBox(true, 0);
>    Lbl *l2 = new Lbl("unmanaged label");
>    box2->pack_start(*l2, Gtk::PACK_EXPAND_WIDGET);
>
>    Gtk::Button btn("delete label boxes");
>    btn.signal_clicked().connect(sigc::ptr_fun(DeleteLabelBoxes));
>
>    vbox.pack_start(*box1, Gtk::PACK_SHRINK);
>    vbox.pack_start(*box2, Gtk::PACK_SHRINK);
>    vbox.pack_start(btn, Gtk::PACK_SHRINK);
>    win.add(vbox);
>
>    win.show_all_children();
>    kit.run(win);
>
>    return 0;
>}
>
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