al_get_display_flags - Allegro 5 API

       Gets the flags of the display.

       In  addition  to the flags set for the display at creation time with al_set_new_display_flags(3alleg5) it
       can also have the ALLEGRO_MINIMIZED flag set, indicating that the window is  currently  minimized.   This
       flag  is  very  platform-dependent  as even a minimized application may still render a preview version so
       normally you should not care whether it is minimized or not.

       al_get_display_flags - Allegro 5 API

al_set_new_display_flags(3alleg5), al_set_display_flag(3alleg5)

Allegro reference manual                                                           al_get_display_flags(3alleg5)

              #include <allegro5/allegro.h>

              int al_get_display_flags(ALLEGRO_DISPLAY *display)