<div dir="ltr"><div>Ok I give up. Could not find simple Gtk3 example in lazarus implementation. So I found another gtk hello world in C based on Gtk3 from: <a href="https://developer.gnome.org/gnome-devel-demos/3.6/checkbutton.c.html.en">https://developer.gnome.org/gnome-devel-demos/3.6/checkbutton.c.html.en</a> . But same error with division by zero:<br>
<br>var<br>  window: PGtkWidget;<br>  app: PGtkApplication;<br>  status: Integer;<br><br>  procedure activate; cdecl;<br>  begin<br>    window := gtk_application_window_new(app);<br>    gtk_window_set_title(PGtkWindow(window), 'CheckButton Example');<br>
    gtk_window_set_default_size (PGtkWindow(window), 300, 100);<br><br>    gtk_widget_show_all(window);<br>  end; <br><br>begin<br>  g_type_init();<br>  app := gtk_application_new ('org.example.checkbutton', G_APPLICATION_FLAGS_NONE);<br>
  g_signal_connect_data(app, 'activate', @activate, nil, nil, 0);<br>  status := g_application_run (PGApplication(app), argc, argv);<br>  g_object_unref (app);  <br></div>end.<br></div>