Man pages matching name lock_variable in section 3alleg4:

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