opendarwin man page for create_system_bitmap

create_system_bitmap(3alleg4)					  Allegro manual				     create_system_bitmap(3alleg4)

NAME
       create_system_bitmap - Creates a system memory bitmap. Allegro game programming library.

SYNOPSIS
       #include <allegro.h>

       BITMAP *create_system_bitmap(int width, int height);

DESCRIPTION
       Allocates  a system memory bitmap of the specified size. Read the introduction of this chapter for a comparison with other types of bitmaps
       and other specific details.

RETURN VALUE
       Returns a pointer to the bitmap on success, NULL otherwise. Remember to destroy this bitmap before any subsequent call to set_gfx_mode().

SEE ALSO
       create_bitmap(3alleg4),	create_bitmap_ex(3alleg4),  create_video_bitmap(3alleg4),   create_sub_bitmap(3alleg4),   destroy_bitmap(3alleg4),
       is_system_bitmap(3alleg4), clear_bitmap(3alleg4), clear_to_color(3alleg4), exupdate(3alleg4)

Allegro 							   version 4.4.2				     create_system_bitmap(3alleg4)