#include <iostream>
#include <gtkmm.h>

void standalone_function ()
{
    std::cout << "standalone_function" << std::endl;
}

class MyButton : public Gtk::Button
{
    public:
        MyButton (const Glib::ustring& lbl) :
            Gtk::Button (lbl) {}
        void on_clicked () { std::cout << "on_clicked" << std::endl; }
};

class AnotherButton : public Gtk::Button
{
    public:
        AnotherButton (const Glib::ustring& lbl) :
            Gtk::Button (lbl)
        {
            signal_clicked ().connect (sigc::mem_fun (*this,
                        &AnotherButton::my_handler));
        }

        void my_handler ()
        {
            std::cout << "my_handler" << std::endl;
        }
};


int main(int argc, char** argv)
{
    Gtk::Main kit (argc, argv);

    // if you don't use inheritance, connect to the signal
    Gtk::Button button1 ("ptr_fun");
    button1.signal_clicked ().connect (sigc::ptr_fun (&standalone_function));

    // this class defines the virtual function on_clicked, which will automatically
    // run when the signal is emitted, you don't need to explicitly connect it.
    MyButton button2 ("on_clicked");

    AnotherButton button3 ("mem_fun");

    Gtk::Window win;
    Gtk::VBox vbox;
    win.add (vbox);
    vbox.pack_start (button1);
    vbox.pack_start (button2);
    vbox.pack_start (button3);
    win.show_all ();

    Gtk::Main::run (win);
}