al_get_joystick_active - Allegro 5 API

       Return  if the joystick handle is “active”, i.e. in the current configuration, the handle represents some
       physical device plugged  into  the  system.   al_get_joystick(3alleg5)  returns  active  handles.   After
       reconfiguration, active handles may become inactive, and vice versa.

       al_get_joystick_active - Allegro 5 API

al_reconfigure_joysticks(3alleg5)

Allegro reference manual                                                         al_get_joystick_active(3alleg5)

              #include <allegro5/allegro.h>

              bool al_get_joystick_active(ALLEGRO_JOYSTICK *joy)