Man pages matching name create_bitmap_ex in section 3alleg4:

create_bitmap_ex.3alleg4.en	debian 10 / allegro4-doc
create_bitmap_ex.3alleg4.en	debian 11 / allegro4-doc
create_bitmap_ex.3alleg4.en	debian 12 / allegro4-doc
create_bitmap_ex.3alleg4.en	debian 13 / allegro4-doc