#include <efl_extension.h>
static void win_back_cb(void *ad)
{
	/* win_back callback implementation */
	appdata_s *ad = data;
        dlog_print(DLOG_ERROR, LOG_TAG, "Wearable Back Button Event Callback Triggered.");
	/* … … … */
}

static void create_base_gui(appdata_s *ad)
{
	/* Window */
	ad->win = elm_win_util_standard_add(PACKAGE, PACKAGE);
	elm_win_autodel_set(ad->win, EINA_TRUE);

	if (elm_win_wm_rotation_supported_get(ad->win)) {
		int rots[4] = { 0, 90, 180, 270 };
		elm_win_wm_rotation_available_rotations_set(ad->win, (const int *)(&rots), 4);
	}
	evas_object_smart_callback_add(ad->win, "delete,request", win_delete_request_cb, NULL);

	/*Since since 2.3.1
	 Adding(/registering)  callback function to ad->win  evas object.*/
	eext_object_event_callback_add(ad->win, EEXT_CALLBACK_BACK, win_back_cb, ad);
	
	/* Conformant Implementation Area */
        /* … … … */


	/* Other GUI functionality implementation area */
	/* … … … */

	/* Show window after base gui is set up */
	evas_object_show(ad->win);
}