is_video_bitmap - Tells if a bitmap is a screen bitmap, video memory or
sub bitmap. Allegro game programming library.
#include <allegro.h>
int is_video_bitmap(BITMAP *bmp);
Returns TRUE if bmp is the screen bitmap, a video memory bitmap, or a
sub-bitmap of either.
screen(3alleg), create_video_bitmap(3alleg), create_sub_bitmap(3alleg)