al_set_d3d_device_release_callback - Allegro 5 API

       The callback will be called whenever a D3D device is reset (minimize, toggle fullscreen window, etc).  In
       the  callback  you should release any d3d resources you have created yourself.  The callback receives the
       affected display as a parameter.

       Pass NULL to disable the callback.

       al_set_d3d_device_release_callback - Allegro 5 API

       5.1.0

Allegro reference manual                                             al_set_d3d_device_release_callback(3alleg5)

              #include <allegro5/allegro_direct3d.h>

              void al_set_d3d_device_release_callback(
                 void (*callback)(ALLEGRO_DISPLAY *display))