get_desktop_resolution - Finds out the desktop resolution. Allegro game programming library.

       Finds  out  the  currently  selected  desktop  resolution. You can use this information to avoid creating
       windows bigger than the current resolution.  This is especially important for some windowed drivers which
       are unable to create windows bigger than the desktop. Each parameter is a pointer to an integer where one
       dimension of the screen will be stored.

       Under some OSes, switching  to  a  full  screen  graphics  mode  may  automatically  change  the  desktop
       resolution.  You  have,  therefore,  to  call  this function before setting any graphics mode in order to
       retrieve the real desktop resolution. Example:

          int width, height;

          allegro_init();
          ...
          if (get_desktop_resolution(&width, &height) == 0) {
             /* Got the resolution correctly */
          }

       get_desktop_resolution - Finds out the desktop resolution. Allegro game programming library.

       Returns zero on success, or a negative number if this information is not available or does not apply,  in
       which case the values stored in the variables you provided for `width' and `height' are undefined.

desktop_color_depth(3alleg4), set_gfx_mode(3alleg4)

Allegro                                           version 4.4.3                  get_desktop_resolution(3alleg4)

#include<allegro.h>intget_desktop_resolution(int*width,int*height);