epoll例子

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#include <stdio.h>  
#include <unistd.h>  
#include <stdlib.h>  
#include <string.h>  
#include <sys/types.h>  
#include <errno.h>  
#include <sys/socket.h>  
#include <netinet/in.h>           /* socket类定义需要*/  
#include <sys/epoll.h>            /* epoll头文件 */  
#include <fcntl.h>                    /* nonblocking需要 */  
#include <sys/resource.h>     /* 设置最大的连接数需要setrlimit */  
  
#define MAXEPOLL    10000   /* 对于服务器来说，这个值可以很大的！ */  
#define MAXLINE     1024  
#define     PORT            6000  
#define MAXBACK 1000  
  
//!> 设置非阻塞  
//!>   
int setnonblocking( int fd )  
{  
    if( fcntl( fd, F_SETFL, fcntl( fd, F_GETFD, 0 )|O_NONBLOCK ) == -1 )  
    {  
        printf("Set blocking error : %d\n", errno);  
        return -1;  
    }  
    return 0;  
}  
  
int main( int argc, char ** argv )  
{  
    int         listen_fd;  
    int         conn_fd;  
    int         epoll_fd;  
    int         nread;  
    int         cur_fds;                //!> 当前已经存在的数量  
    int         wait_fds;               //!> epoll_wait 的返回值  
    int     i;  
    struct sockaddr_in servaddr;  
    struct sockaddr_in cliaddr;  
    struct  epoll_event ev;  
    struct  epoll_event evs[MAXEPOLL];  
    struct  rlimit  rlt;        //!> 设置连接数所需  
    char    buf[MAXLINE];  
    socklen_t   len = sizeof( struct sockaddr_in );  
  
    //!> 设置每个进程允许打开的最大文件数  
    //!> 每个主机是不一样的哦，一般服务器应该很大吧！  
    //!>   
    rlt.rlim_max = rlt.rlim_cur = MAXEPOLL;  
    if( setrlimit( RLIMIT_NOFILE, &rlt ) == -1 )      
    {  
        printf("Setrlimit Error : %d\n", errno);  
        exit( EXIT_FAILURE );  
    }  
      
    //!> server 套接口  
    //!>   
    bzero( &servaddr, sizeof( servaddr ) );  
    servaddr.sin_family = AF_INET;  
    servaddr.sin_addr.s_addr = htonl( INADDR_ANY );  
    servaddr.sin_port = htons( PORT );  
      
    //!> 建立套接字  
    if( ( listen_fd = socket( AF_INET, SOCK_STREAM, 0 ) ) == -1 )  
    {  
        printf("Socket Error...\n" , errno );  
        exit( EXIT_FAILURE );  
    }  
      
    //!> 设置非阻塞模式  
    //!>   
    if( setnonblocking( listen_fd ) == -1 )  
    {  
        printf("Setnonblocking Error : %d\n", errno);  
        exit( EXIT_FAILURE );  
    }  
      
    //!> 绑定  
    //!>  
    if( bind( listen_fd, ( struct sockaddr *)&servaddr, sizeof( struct sockaddr ) ) == -1 )  
    {  
        printf("Bind Error : %d\n", errno);  
        exit( EXIT_FAILURE );  
    }  
  
    //!> 监听  
    //!>   
    if( listen( listen_fd, MAXBACK ) == -1 )  
    {  
        printf("Listen Error : %d\n", errno);  
        exit( EXIT_FAILURE );  
    }  
      
    //!> 创建epoll  
    //!>   
    epoll_fd = epoll_create( MAXEPOLL );    //!> create  
    ev.events = EPOLLIN | EPOLLET;      //!> accept Read!  
    ev.data.fd = listen_fd;                 //!> 将listen_fd 加入  
    if( epoll_ctl( epoll_fd, EPOLL_CTL_ADD, listen_fd, &ev ) < 0 )  
    {  
        printf("Epoll Error : %d\n", errno);  
        exit( EXIT_FAILURE );  
    }  
    cur_fds = 1;  
      
    while( 1 )  
    {  
        if( ( wait_fds = epoll_wait( epoll_fd, evs, cur_fds, -1 ) ) == -1 )  
        {  
            printf( "Epoll Wait Error : %d\n", errno );  
            exit( EXIT_FAILURE );  
        }  
  
        for( i = 0; i < wait_fds; i++ )  
        {  
            if( evs[i].data.fd == listen_fd && cur_fds < MAXEPOLL )    
                                                    //!> if是监听端口有事  
            {  
                if( ( conn_fd = accept( listen_fd, (struct sockaddr *)&cliaddr, &len ) ) == -1 )  
                {  
                    printf("Accept Error : %d\n", errno);  
                    exit( EXIT_FAILURE );  
                }  
                  
                printf( "Server get from client !\n"/*,  inet_ntoa(cliaddr.sin_addr), cliaddr.sin_port */);  
                  
                ev.events = EPOLLIN | EPOLLET;      //!> accept Read!  
                ev.data.fd = conn_fd;                   //!> 将conn_fd 加入  
                if( epoll_ctl( epoll_fd, EPOLL_CTL_ADD, conn_fd, &ev ) < 0 )  
                {  
                    printf("Epoll Error : %d\n", errno);  
                    exit( EXIT_FAILURE );  
                }  
                ++cur_fds;   
                continue;         
            }  
              
            //!> 下面处理数据  
            //!>   
            nread = read( evs[i].data.fd, buf, sizeof( buf ) );  
            if( nread <= 0 )                     //!> 结束后者出错  
            {  
                close( evs[i].data.fd );  
                epoll_ctl( epoll_fd, EPOLL_CTL_DEL, evs[i].data.fd, &ev );  //!> 删除计入的fd  
                --cur_fds;                  //!> 减少一个呗！  
                continue;  
            }  
              
            write( evs[i].data.fd, buf, nread );            //!> 回写  
              
        }  
    }  
      
    close( listen_fd );  
    return 0;  
}