al_clear_keyboard_state - Allegro 5 API

       Clear  the  state of the keyboard, emitting ALLEGRO_EVENT_KEY_UP(3alleg5) for each currently pressed key.
       The given display is regarded as the one which had the keyboard focus when the event occurred.   In  case
       display  is  NULL  no event is emitted.  For most keyboard drivers Allegro maintains its own state of the
       keyboard, which might get out of sync with the real one.   This  function  is  intended  to  remedy  such
       situation  by  resetting  Allegro’s  keyboard  state  to  a  known  default  (no  key  pressed).  This is
       particularly useful in response to ALLEGRO_EVENT_DISPLAY_SWITCH_OUT(3alleg5) events.

       al_clear_keyboard_state - Allegro 5 API

al_get_keyboard_state(3alleg5), ALLEGRO_KEYBOARD_STATE(3alleg5)

       5.2.3

              [UnstableAPI]: This is a new feature and the exact semantics are still being decided upon.

Allegro reference manual                                                        al_clear_keyboard_state(3alleg5)

              #include <allegro5/allegro.h>

              void al_clear_keyboard_state(ALLEGRO_DISPLAY *display)