keyboard_check(key) Returns whether the key with the particular keycode is currently down.
keyboard_check_pressed(key) Returns whether the key with the particular keycode was pressed since the last step.
keyboard_check_released(key) Returns whether the key with the particular keycode was released since the last step.
keyboard_check_direct(key) Returns whether the key with the particular keycode is pressed by checking the hardware directly. The result is independent of which application has focus. It allows for a few more checks.