[c语言 ] 用libev 写个echo服务器
放假了.同学都回家了,我是更情愿留久点在学校,一来学校安静,二来免得火车太挤. 这临走前的几天,放下了erlang,写了一下c. 其实只是对比下erlang 写socket服务器,和c写socket服务器的异同.
编译后,运行. 然后打开teminal , telnet 127.0.0.1 9999 就可以发送信息了.
说一下libev: 点击打开链接
Libev是一个event loop:向libev注册感兴趣的events,比如Socket可读事件,libev会对所注册的事件的源进行管理,并在事件发生时触发相应的程序。 对比另外一个更加出名的libevent,这个更加先进. 小巧轻量. 源码解读就不献丑了,一堆堆宏.我功力不够去深层切入libev.官网有文档,弄成pdf了,可以下载: http://d.yun.io/Y9ziuo
说一下环境: ubuntu 11.10 ,gcc4.4.6 ,libev 4.11, code:block(vim,emacs党...莫要黑,我用CB好久了,莫要离间!!!)
官方文档是有个键盘输入的demo,网上也有几个用libev写echo sever的,感觉都写得很不错,很全面. 我还是参考他们写个简单,简陋的试一下吧.
main.c 只有一个文件..呵呵
- #include <stdio.h>
- #include <netinet/in.h>
- #include <ev.h>
- #define PORT 9999
- #define BUFFER_SIZE 1024
- void accept_cb(struct ev_loop *loop, struct ev_io *watcher, int revents);
- void read_cb(struct ev_loop *loop, struct ev_io *watcher, int revents);
- int main()
- {
- struct ev_loop *loop = ev_default_loop(0);
- int sd;
- struct sockaddr_in addr;
- int addr_len = sizeof(addr);
- struct ev_io socket_accept;
- // 创建socket的写法,这里简单处理,用INADDR_ANY ,匹配任何客户端请求.这里写法都一样,没什么特别的,直接copy都可以用
- if( (sd = socket(PF_INET, SOCK_STREAM, 0)) < 0 )
- {
- printf("socket error");
- return -1;
- }
- bzero(&addr, sizeof(addr));
- addr.sin_family = AF_INET;
- addr.sin_port = htons(PORT);
- addr.sin_addr.s_addr = INADDR_ANY;
- if (bind(sd, (struct sockaddr*) &addr, sizeof(addr)) != 0)
- {
- printf("bind error");
- }
- if (listen(sd, 2) < 0)
- {
- printf("listen error");
- return -1;
- }
- // 初始化,这里监听了io事件,写法参考官方文档的
- ev_io_init(&socket_accept, accept_cb, sd, EV_READ);
- ev_io_start(loop, &socket_accept);
- while (1)
- {
- ev_loop(loop, 0);
- }
- return 0;
- }
- //accept事件 的回调块
- void accept_cb(struct ev_loop *loop, struct ev_io *watcher, int revents)
- {
- struct sockaddr_in client_addr;
- socklen_t client_len = sizeof(client_addr);
- int client_sd;
- //分派客户端的ev io结构
- struct ev_io *w_client = (struct ev_io*) malloc (sizeof(struct ev_io));
- //libev的错误处理
- if(EV_ERROR & revents)
- {
- printf("error event in accept");
- return;
- }
- //accept,普通写法
- client_sd = accept(watcher->fd, (struct sockaddr *)&client_addr, &client_len);
- if (client_sd < 0)
- {
- printf("accept error");
- return;
- }
- printf("someone connected.\n");
- //开始监听读事件了,有客户端信息就会被监听到
- ev_io_init(w_client, read_cb, client_sd, EV_READ);
- ev_io_start(loop, w_client);
- }
- //read 数据事件的回调快
- void read_cb(struct ev_loop *loop, struct ev_io *watcher, int revents){
- char buffer[BUFFER_SIZE];
- ssize_t read;
- if(EV_ERROR & revents)
- {
- printf("error event in read");
- return;
- }
- //recv普通socket写法
- read = recv(watcher->fd, buffer, BUFFER_SIZE, 0);
- if(read < 0)
- {
- printf("read error");
- return;
- }
- //断开链接的处理,停掉evnet就可以,同时记得释放客户端的结构体!
- if(read == 0)
- {
- printf("someone disconnected.\n");
- ev_io_stop(loop,watcher);
- free(watcher);
- return;
- }
- else
- {
- printf("get the message:%s\n",buffer);
- }
- //原信息返回,也可以自己写信息,都一样.最后记得置零
- send(watcher->fd, buffer, read, 0);
- bzero(buffer, read);
- }
编译后,运行. 然后打开teminal , telnet 127.0.0.1 9999 就可以发送信息了.
入手c的网络编程,将来,对比下erlang的底层网络通讯是怎么弄的
~~by dp