al_set_display_flag - Allegro 5 API

       Enable    or    disable    one   of   the   display   flags.    The   flags   are   the   same   as   for
       al_set_new_display_flags(3alleg5).  The only flags that can be changed after creation are:

       • ALLEGRO_FULLSCREEN_WINDOW

       • ALLEGRO_FRAMELESS

       • ALLEGRO_MAXIMIZED

       Returns  true  if  the  driver  supports  toggling  the  specified  flag  else  false.    You   can   use
       al_get_display_flags(3alleg5) to query whether the given display property actually changed.

       al_set_display_flag - Allegro 5 API

al_set_new_display_flags(3alleg5), al_get_display_flags(3alleg5)

Allegro reference manual                                                            al_set_display_flag(3alleg5)

       5.0.7, 5.1.2

              #include <allegro5/allegro.h>

              bool al_set_display_flag(ALLEGRO_DISPLAY *display, int flag, bool onoff)