Getting keyboard modifiers state using Gnome libs (GDK) fetches initial state only

Question

I\'m trying to get the current keyboard modifiers state through gnome GDK or GTK library in aim to implement an accessibility gnome shell extension that shows that state.

Answer 1

• Indeed, I need an event loop as andlabs said in his comment. His suggestion to use GTK gtk_init() & gtk_main() works perfectly.

  /*
   * compiling: gcc `pkg-config --cflags gtk+-3.0` -o gtk_xkbmod3 gtk_xkbmod3.c `pkg-config --libs gtk+-3.0`
   */
  
  #include 
  
  static void update(GdkKeymap * kmap) {
      guint state;
      state = gdk_keymap_get_modifier_state(kmap);
      g_printf("%i\n", state);
  }
  
  int main (int argc, char **argv) {
  
      gtk_init(&argc, &argv);
  
      GdkKeymap * kmap;
      kmap = gdk_keymap_get_default();
  
      g_timeout_add_seconds(1, (GSourceFunc) update, kmap);
  
      gtk_main();
  
  }
  

• I could also use GDK with GLib GMainLoop.

  /*
   * compiling: gcc `pkg-config --cflags gdk-3.0` -o gdk_xkbmod4 gdk_xkbmod4.c `pkg-config --libs gdk-3.0`
   */
  
  #include 
  
  GMainLoop *mainloop;
  
  static void update(GdkKeymap * kmap) {
      guint state;
      state = gdk_keymap_get_modifier_state(kmap);
      g_printf("%i\n", state);
  }
  
  int main (int argc, char **argv) {    
  
      gdk_init(&argc, &argv);
  
      GdkKeymap * kmap;
      kmap = gdk_keymap_get_default();
  
      g_timeout_add_seconds(1, (GSourceFunc) update, kmap);
  
      mainloop = g_main_loop_new(g_main_context_default(), FALSE);
      g_main_loop_run(mainloop);    
  }
  

References:

• Xfce Foundation Classes: The Main Event Loop
• GTK+ Forums: GDK + GLib main loop