poll_keyboard(3) - Linux man page
Name
poll_keyboard - Polls the keyboard. Allegro game programming library.Synopsis
#include <allegro.h>int poll_keyboard();
Description
To help you test your keyboard polling code even if you are programming on a platform that doesn't require it, after the first time that you call this function Allegro will switch into polling mode, so from that point onwards you will have to call this routine in order to get any keyboard input at all, regardless of whether the current driver actually needs to be polled or not.
The keypressed(), readkey(), and ureadkey() functions call poll_keyboard() automatically, so you only need to use this function when accessing the key[] array and key_shifts variable.