ALLEGRO_MONITOR_INFO - Allegro 5 API

       Describes  a  monitor’s size and position relative to other monitors.  x1, y1 will be 0, 0 on the primary
       display.  Other monitors can have negative values if they are to the left or above the  primary  display.
       x2,  y2  are  the  coordinates one beyond the bottom right pixel, so that x2-x1 gives the width and y2-y1
       gives the height of the display.

              typedef struct ALLEGRO_MONITOR_INFO
              {
                 int x1;
                 int y1;
                 int x2;
                 int y2;
              } ALLEGRO_MONITOR_INFO;

       ALLEGRO_MONITOR_INFO - Allegro 5 API

al_get_monitor_info(3alleg5)

Allegro reference manual                                                           ALLEGRO_MONITOR_INFO(3alleg5)

              #include <allegro5/allegro.h>

              typedef struct ALLEGRO_MONITOR_INFO