使用 libevent 实现客户端

int bufferevent_socket_connect(struct bufferevent *bev,
    struct sockaddr *address, int addrlen); The address and addrlen arguments are as for the standard call connect(). If the bufferevent does not already have a socket set, calling this function allocates a new stream socket for it, and makes it nonblocking.

#include <event2/event.h>
#include <event2/bufferevent.h>
#include <sys/socket.h>
#include <string.h>

void eventcb(struct bufferevent *bev, short events, void *ptr)
{
    if (events & BEV_EVENT_CONNECTED) {
        /* We're connected to 127.0.0.1:8080.   Ordinarily we'd do
            something here, like start reading or writing. */
    } else if (events & BEV_EVENT_ERROR) {
        /* An error occured while connecting. */
        bufferevent_free(bev);
        event_base_loopexit((struct event_base *)ptr, NULL);
    }
}

int main_loop(void)
{
    struct event_base *base;
    struct bufferevent *bev;
    struct sockaddr_in sin;

    base = event_base_new();

    memset(&sin, 0, sizeof(sin));
    sin.sin_family = AF_INET;
    sin.sin_addr.s_addr = htonl(0x7f000001); /* 127.0.0.1 */
    sin.sin_port = htons(8080); /* Port 8080 */

    bev = bufferevent_socket_new(base, -1, BEV_OPT_CLOSE_ON_FREE);

    bufferevent_setcb(bev, NULL, NULL, eventcb, base);

    if (bufferevent_socket_connect(bev,
        (struct sockaddr *)&sin, sizeof(sin)) < 0) {
        /* Error starting connection */
        bufferevent_free(bev);
        event_base_free(base);
        return -1;
    }

    event_base_dispatch(base);
    event_base_free(base);
    return 0;
}