一个并发10k的简易群聊天室（使用epoll）

local.h

#include <sys/socket.h>
#include <sys/epoll.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <time.h>
#include <list>
#include <string.h>

#define BUF_SIZE 1024 //默认缓冲区
#define SERVER_PORT 8888 //监听端口
//#define SERVER_HOST "192.168.34.15" //服务器IP地址
#define SERVER_HOST "127.0.0.1" //服务器IP地址
#define EPOLL_RUN_TIMEOUT -1 //epoll的超时时间
#define EPOLL_SIZE 10000 //epoll监听的客户端的最大数目

#define STR_WELCOME "Welcome to seChat! You ID is: Client #%d"
#define STR_MESSAGE "Client #%d>> %s"
#define STR_NOONE_CONNECTED "Noone connected to server except you!"
#define CMD_EXIT "EXIT"

//两个有用的宏定义：检查和赋值并且检测
#define CHK(eval) if(eval < 0){perror("eval"); exit(-1);}
#define CHK2(res, eval) if((res = eval) < 0){perror("eval"); exit(-1);}

//================================================================================================
//函数名：                  setnonblocking
//函数描述：                设置socket为不阻塞
//输入： [in] sockfd socket标示符
//输出：                    无
//返回：                    0
//================================================================================================
int setnonblocking(int sockfd);

//================================================================================================
//函数名：                  handle_message
//函数描述：                处理每个客户端socket
//输入： [in] new_fd socket标示符
//输出：                    无
//返回：                    返回从客户端接受的数据的长度
//================================================================================================
int handle_message(int new_fd);

utils.h

#include "local.h"


int setnonblocking(int sockfd)
{
    CHK(fcntl(sockfd, F_SETFL, fcntl(sockfd, F_GETFD, 0)|O_NONBLOCK));
    return 0;
}

server.cpp

#include "local.h"
#include "utils.h"

using namespace std;

// 存放客户端socket描述符的list
list<int> clients_list;

int main(int argc, char *argv[])
{
    int listener; //监听socket
    struct sockaddr_in addr, their_addr;
    addr.sin_family = PF_INET;
    addr.sin_port = htons(SERVER_PORT);
    addr.sin_addr.s_addr = inet_addr(SERVER_HOST);
    socklen_t socklen;
    socklen = sizeof(struct sockaddr_in);

    static struct epoll_event ev, events[EPOLL_SIZE];
    ev.events = EPOLLIN | EPOLLET; //对读感兴趣，边沿触发

    char message[BUF_SIZE];

    int epfd; //epoll描述符
    clock_t tStart; //计算程序运行时间

    int client, res, epoll_events_count;

    CHK2(listener, socket(PF_INET, SOCK_STREAM, 0)); //初始化监听socket
    setnonblocking(listener); //设置监听socket为不阻塞
    CHK(bind(listener, (struct sockaddr *)&addr, sizeof(addr))); //绑定监听socket
    CHK(listen(listener, 1)); //设置监听

    CHK2(epfd,epoll_create(EPOLL_SIZE)); //创建一个epoll描述符，并将监听socket加入epoll
    ev.data.fd = listener;
    CHK(epoll_ctl(epfd, EPOLL_CTL_ADD, listener, &ev));

    while(1)
    {
        CHK2(epoll_events_count,epoll_wait(epfd, events, EPOLL_SIZE, EPOLL_RUN_TIMEOUT));
        tStart = clock();
        for(int i = 0; i < epoll_events_count ; i++)
        {
            if(events[i].data.fd == listener) //新的连接到来，将连接添加到epoll中，并发送欢迎消息
            {
                CHK2(client,accept(listener, (struct sockaddr *) &their_addr, &socklen));
                setnonblocking(client);
                ev.data.fd = client;
                CHK(epoll_ctl(epfd, EPOLL_CTL_ADD, client, &ev));

                clients_list.push_back(client); // 添加新的客户端到list
                bzero(message, BUF_SIZE);
                res = sprintf(message, STR_WELCOME, client);
                CHK2(res, send(client, message, BUF_SIZE, 0));

            }else
            {
                CHK2(res,handle_message(events[i].data.fd)); //注意：这里并没有调用epoll_ctl重新设置socket的事件类型，但还是可以继续收到客户端发送过来的信息
            }
        }
        printf("Statistics: %d events handled at: %.2f second(s)\n", epoll_events_count, (double)(clock() - tStart)/CLOCKS_PER_SEC);
    }

    close(listener);
    close(epfd);

    return 0;
}

int handle_message(int client)
{
    char buf[BUF_SIZE], message[BUF_SIZE];
    bzero(buf, BUF_SIZE);
    bzero(message, BUF_SIZE);

    int len;

    CHK2(len,recv(client, buf, BUF_SIZE, 0)); //接受客户端信息

    if(len == 0) //客户端关闭或出错，关闭socket，并从list移除socket
    {
        CHK(close(client));
        clients_list.remove(client);
    }
    else //向客户端发送信息
    {
        if(clients_list.size() == 1)
        {
            CHK(send(client, STR_NOONE_CONNECTED, strlen(STR_NOONE_CONNECTED), 0));
                return len;
        }

        sprintf(message, STR_MESSAGE, client, buf);
        list<int>::iterator it;
        for(it = clients_list.begin(); it != clients_list.end(); it++)
        {
           if(*it != client)
           {
                CHK(send(*it, message, BUF_SIZE, 0));
           }
        }
    }

    return len;
}

10kclient.cpp

#include "local.h"
#include "utils.h"

using namespace std;

char message[BUF_SIZE]; //接受服务器信息
list<int> list_of_clients; //存放所有客户端
int res;
clock_t tStart;

int main(int argc, char *argv[])
{
    int sock;
    struct sockaddr_in addr;
    addr.sin_family = PF_INET;
    addr.sin_port = htons(SERVER_PORT);
    addr.sin_addr.s_addr = inet_addr(SERVER_HOST);

    tStart = clock();

    for(int i=0 ; i<EPOLL_SIZE; i++) //生成EPOLL_SIZE个客户端，这里是10000个，模拟高并发
    {
       CHK2(sock,socket(PF_INET, SOCK_STREAM, 0));
       CHK(connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0);
       list_of_clients.push_back(sock);

       bzero(&message, BUF_SIZE);
       CHK2(res,recv(sock, message, BUF_SIZE, 0));
       printf("%s\n", message);
    }

    list<int>::iterator it; //移除所有客户端
    for(it = list_of_clients.begin(); it != list_of_clients.end() ; it++)
       close(*it);

    printf("Test passed at: %.2f second(s)\n", (double)(clock() - tStart)/CLOCKS_PER_SEC);
    printf("Total server connections was: %d\n", EPOLL_SIZE);

    return 0;
}

参考资料：
google code svn路径：
http://www.cnblogs.com/venow/archive/2012/11/30/2790031.html