Man pages matching name get_sound_input_cap_stereo in section 3alleg4:

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