Allegro 5 api
#include <allegro5/allegro.h> int al_get_display_flags(ALLEGRO_DISPLAY *display)
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_set_new_display_flags(3alleg5), al_set_display_flag(3alleg5)