title: How to check if a radiobutton is selected in GTK
body: <p>I am trying to create a GUI in GTK using C. I want to have radio buttons but I don't know how to determine which one is selected.</p>
  
  <pre><code>#include &lt;glib.h&gt;
  #include &lt;gtk/gtk.h&gt;
  
  static gboolean close_application( GtkWidget *widget,
                                     GdkEvent  *event,
                                     gpointer   data )
  {
    gtk_main_quit ();
    return FALSE;
  }
  
  static void btn_selected()
  {
      //pop-up message; left empty for now   
  }
  
  int main( int   argc,
            char *argv[] )
  {
      GtkWidget *window = NULL;
      GtkWidget *box1;
      GtkWidget *box2;
      GtkWidget *button;
      GtkWidget *separator;
      GSList *group;
  
      gtk_init (&amp;argc, &amp;argv);    
  
      window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  
      g_signal_connect (window, "delete-event",
                G_CALLBACK (close_application),
                        NULL);
  
      gtk_window_set_title (GTK_WINDOW (window), "radio buttons");
      gtk_container_set_border_width (GTK_CONTAINER (window), 0);
  
      box1 = gtk_vbox_new (FALSE, 0);
      gtk_container_add (GTK_CONTAINER (window), box1);
      gtk_widget_show (box1);
  
      box2 = gtk_vbox_new (FALSE, 10);
      gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
      gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
      gtk_widget_show (box2);
  
      button = gtk_radio_button_new_with_label (NULL, "button1");
      gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0);
      gtk_widget_show (button);
  
      group = gtk_radio_button_get_group (GTK_RADIO_BUTTON (button));
      button = gtk_radio_button_new_with_label (group, "button2");
      gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (button), TRUE);
      gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0);
      gtk_widget_show (button);
  
      button = gtk_radio_button_new_with_label_from_widget (GTK_RADIO_BUTTON (button),
                                                        "button3");
      gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0);
      gtk_widget_show (button);
  
      separator = gtk_hseparator_new ();
      gtk_box_pack_start (GTK_BOX (box1), separator, FALSE, TRUE, 0);
      gtk_widget_show (separator);
  
      box2 = gtk_vbox_new (FALSE, 10);
      gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
      gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, TRUE, 0);
      gtk_widget_show (box2);
  
      button = gtk_button_new_with_label ("close");
      g_signal_connect_swapped (button, "clicked",
                                G_CALLBACK (close_application),
                                window);
      gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0);
      gtk_widget_set_can_default (button, TRUE);
      gtk_widget_grab_default (button);
      gtk_widget_show (button);
  
      //This button will call the btn_selected method when clicked
      button = gtk_button_new_with_label("selected");
      g_signal_connect(button,"clicked",G_CALLBACK (btn_selected),NULL);
      gtk_box_pack_start(GTK_BOX(box2),button,TRUE,TRUE,0);
      gtk_widget_show(button);
  
      gtk_widget_show (window);
  
      gtk_main ();
  
      return 0;
  }
  </code></pre>
  
  <p>The GUI comes up without any errors, I just don't know to check which radio button was selected so I can perform an action. Since all the buttons are named button I don't know how to check for a specific one.I got this code from a gtk tutorial online.</p>
  
  <p>Any ideas would be greatly appreciated.</p>