linux系统编程，多路IO，epoll实现群聊

客户端
#include <sys/types.h>        
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h> /* superset of previous */
#include <arpa/inet.h>
#include <string.h>
#include <stdio.h>
#include <pthread.h>

#define IP "192.168.154.14"
#define PORT 44444
int socfd;

void* Fun_W(void* arg)
{
    char buf_w[100];
    while(1)
    {
        memset(buf_w,0,100);
        printf("请输入要写入的内容：\n");
        scanf("%s",buf_w);
        send(socfd,buf_w,strlen(buf_w),0);
    }
}

void* Fun_R(void* arg)
{
    char buf_r[100];
    while(1)
    {
        memset(buf_r,0,100);
        recv(socfd,buf_r,100,0);
        printf("客户端:%s\n",buf_r);
    }
}
int main()
{       
    //创建套接子
    socfd = socket(AF_INET,SOCK_STREAM,0);
    int val=1;
    setsockopt(socfd,SOL_SOCKET,SO_REUSEADDR,&val,sizeof(val));
    if(socfd == -1)
    {
        perror("socfd");
        return -1;
    }
    //连接
    struct sockaddr_in addr;
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = inet_addr(IP);
    addr.sin_port = htons(PORT);
    connect(socfd,(struct sockaddr*)(&addr),sizeof(addr));

    //创建线程去读写
    pthread_t pt1,pt2;
    pthread_create(&pt1,NULL,Fun_W,NULL);
    pthread_create(&pt2,NULL,Fun_R,NULL);

    pthread_join(pt1,NULL);
    pthread_join(pt2,NULL);
    return 0;
}

服务器
#include <sys/types.h>        
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h> /* superset of previous */
#include <arpa/inet.h>
#include <string.h>
#include <stdio.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/epoll.h>

#define IP "192.168.154.14"
#define PORT 44444
/*多路IO复用*/
int main()
{       
    //创建套接子
    int socfd = socket(AF_INET,SOCK_STREAM,0);
    int val=1;
    setsockopt(socfd,SOL_SOCKET,SO_REUSEADDR,&val,sizeof(val));
    if(socfd == -1)
    {
        perror("socfd");
        return -1;
    }
    //绑定
    struct sockaddr_in self;
    self.sin_family=AF_INET;
    self.sin_addr.s_addr=inet_addr(IP);
    self.sin_port=htons(PORT);
    int bd = bind(socfd,(struct sockaddr *)(&self),sizeof(self));
    if(bd == -1)
    {
        perror("bd");
        return -1;
    }
    //监听
    listen(socfd,50);
    //接收

    struct sockaddr_in cli_addr;
    socklen_t len = sizeof(cli_addr);

    //多路IO设置
    int clifd[51],ret=0,count=0;
    char buf[100]={0};
    int epfd = epoll_create(1);//创建句柄即是向内核申请空间，用来存放FD的事件
    struct epoll_event ev;
    ev.events=EPOLLIN;//设置数据可读
    ev.data.fd=socfd;//设置套接子
    epoll_ctl(epfd,EPOLL_CTL_ADD,socfd,&ev);//将fd加入到列表中
    struct epoll_event retev[51];//创建一个结构体下面用来连接时，保存连接的是那个客户端
    while(1)
    {
        int ret = epoll_wait(epfd,retev,51,-1);//阻塞监测事件，返回值是事件的个数
        if(ret == -1)
        {
            perror("epoll_wait");
            return -1;
        }
        for(int i=0;i<ret;i++)
        {
            if((retev[i].data.fd == socfd)&&(retev[i].events&EPOLLIN))//如果是可读连接，
            {
                clifd[count] = accept(socfd,(struct sockaddr *)(&cli_addr),&len);//接收连接信息
                printf("%d客户端上线\n",clifd[count]);
                ev.events=EPOLLIN;
                ev.data.fd=clifd[count];//重新设置其套接子为客户端的套接子
                epoll_ctl(epfd,EPOLL_CTL_ADD,clifd[count],&ev);//添加到事件中
                count++;

            }
            else if((retev[i].data.fd != socfd)&&(retev[i].events&EPOLLIN))//如果不是连接，是读操作
            {
                int re = retev[i].data.fd;
                memset(buf,0,100);
                int a = read(re,buf,100);//读数据
                for(int i=0;i<count;i++)
                {
                    if(re!=clifd[i]&&clifd[i]>0)
                        write(clifd[i],buf,strlen(buf));//发送给除了自己的其他人
                }
                if(a == 0)//如果没有读到内容，则客户端下线
                {
                    printf("%d客户端下线\n",re);
                    for(int j=0;j<count;j++)
                    {
                        if(re == clifd[j])
                            clifd[j]=0;
                    }
                    epoll_ctl(epfd,EPOLL_CTL_DEL,re,NULL);//把事件中该客户端的内容删除
                }

            }
        }

    }
    return 0;
}