simple_event.c

#include <stdio.h>
#include <allegro5/allegro.h>

int main(int argc, char **argv) {
    ALLEGRO_DISPLAY *display = NULL;
    ALLEGRO_EVENT_QUEUE *event_queue = NULL;

    // Initialize Allegro Library
    if (!al_init()) {
        fprintf(stderr, "failed to initialize allegro\n");
        return -1;
    }
    // Create Display
    display = al_create_display(640, 480);
    if (!display) {
        fprintf(stderr, "failed to create display\n");
        return -1;
    }

    event_queue = al_create_event_queue();
    if (!event_queue) {
        fprintf(stderr, "failed to create event_queue\n");
        al_destroy_display(display);
        return -1;
    }
    // Tie events from display to the event queue
    al_register_event_source(event_queue, al_get_display_event_source(display));
    al_clear_to_color(al_map_rgb(0, 0, 0));
    al_flip_display();

    while (true) {
        ALLEGRO_EVENT ev;
        ALLEGRO_TIMEOUT timeout;
        al_init_timeout(&timeout, 0.06);

        // wait for an amount of time specified by timeout for an event
        // if we got an event, get_event == true
        bool get_event = al_wait_for_event_until(event_queue, &ev, &timeout);

        if (get_event && ev.type == ALLEGRO_EVENT_DISPLAY_CLOSE) {
            break;
        }

        al_clear_to_color(al_map_rgb(0, 0, 0));
        al_flip_display();
    }

    al_destroy_display(display);
    al_destroy_event_queue(event_queue);

    return 0;
}