libevent库的使用方法实例

void connection_time(int fd, short event, struct event *arg)  
{  
    char buf[32];  
    struct tm t;  
    time_t now;  

    time(&now);  
    localtime_r(&now, &t);  
    asctime_r(&t, buf);  

    write(fd, buf, strlen(buf));  
    shutdown(fd, SHUT_RDWR);  

    free(arg);  
}  

void connection_accept(int fd, short event, void *arg)  
{  
    /* for debugging */
    fprintf(stderr, "%s(): fd = %d, event = %d.\n", __func__, fd, event);  

    /* Accept a new connection. */
    struct sockaddr_in s_in;  
    socklen_t len = sizeof(s_in);  
    int ns = accept(fd, (struct sockaddr *) &s_in, &len);  
    if (ns < 0) {  
        perror("accept");  
        return;  
    }  

    /* Install time server. */
    struct event *ev = malloc(sizeof(struct event));  
    event_set(ev, ns, EV_WRITE, (void *) connection_time, ev);  
    event_add(ev, NULL);  
}  

int main(void)  
{  
    /* Request socket. */
    int s = socket(PF_INET, SOCK_STREAM, 0);  
    if (s < 0) {  
        perror("socket");  
        exit(1);  
    }  

    /* bind() */
    struct sockaddr_in s_in;  
    bzero(&s_in, sizeof(s_in));  
    s_in.sin_family = AF_INET;  
    s_in.sin_port = htons(7000);  
    s_in.sin_addr.s_addr = INADDR_ANY;  
    if (bind(s, (struct sockaddr *) &s_in, sizeof(s_in)) < 0) {  
        perror("bind");  
        exit(1);  
    }  

    /* listen() */
    if (listen(s, 5) < 0) {  
        perror("listen");  
        exit(1);  
    }  

    /* Initial libevent. */
    event_init();  

    /* Create event. */
    struct event ev;  
    event_set(&ev, s, EV_READ | EV_PERSIST, connection_accept, &ev);  

    /* Add event. */
    event_add(&ev, NULL);  

    event_dispatch();  

    return 0;  
}

void printbuf(struct evbuffer *evbuf)  
{  
    for (;;) {  
        char *buf = evbuffer_readline(evbuf);  
        printf("* buf = %p, the string = \"\e[1;33m%s\e[m\"\n", buf, buf);  
        if (buf == NULL)  
            break;  
        free(buf);  
    }  
}  

int main(void)  
{  
    struct evbuffer *evbuf;  

    evbuf = evbuffer_new();  
    if (evbuf == NULL) {  
        fprintf(stderr, "%s(): evbuffer_new() failed.\n", __func__);  
        exit(1);  
    }  

    /* Add "gslin" into buffer. */
    u_char *buf1 = "gslin";  
    printf("* Add \"\e[1;33m%s\e[m\".\n", buf1);  
    evbuffer_add(evbuf, buf1, strlen(buf1));  
    printbuf(evbuf);  

    u_char *buf2 = " is reading.\nAnd he is at home.\nLast.";  
    printf("* Add \"\e[1;33m%s\e[m\".\n", buf2);  
    evbuffer_add(evbuf, buf2, strlen(buf2));  
    printbuf(evbuf);  

    evbuffer_free(evbuf);  
}