C++ libevent 搭建服务器代码

以下是一个简单的 C++ libevent 服务器代码示例：

#include <event2/event.h>
#include <event2/buffer.h>
#include <event2/bufferevent.h>
#include <event2/listener.h>

#include <string>
#include <iostream>

using namespace std;

void onRead(bufferevent *bev, void *ctx) {
    char msg[4096];
    size_t len = bufferevent_read(bev, &msg, sizeof(msg));
    msg[len] = '\0';
    cout << "Received message: " << msg << endl;
    bufferevent_write(bev, "Server received the message.", 30);
}

void onAccept(evconnlistener *listener, evutil_socket_t fd, sockaddr *addr, int socklen, void *ctx) {
    event_base *base = evconnlistener_get_base(listener);
    bufferevent *bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
    bufferevent_setcb(bev, onRead, nullptr, nullptr, nullptr);
    bufferevent_enable(bev, EV_READ | EV_WRITE);
}

int main() {
    event_base *base = event_base_new();
    sockaddr_in sin;
    sin.sin_family = AF_INET;
    sin.sin_addr.s_addr = htonl(INADDR_ANY);
    sin.sin_port = htons(8888);

    evconnlistener *listener = evconnlistener_new_bind(base, onAccept, nullptr, LEV_OPT_CLOSE_ON_FREE | LEV_OPT_REUSEABLE, -1, (sockaddr *)&sin, sizeof(sin));
    event_base_dispatch(base);
    return 0;
}

这个服务器监听 8888 端口，并在接收到客户端的连接请求时响应。当收到客户端的消息时，它将输出消息并回复 "Server received the message."。

在编译时需要添加如下链接库：

-lpthread -levent -levent_core -levent_extra