*select_socket.c*/   
#include <SYS types.h>    
#include <SYS socket.h>    
#include <SYS wait.h>    
#include <STDIO.H>    
#include <STDLIB.H>    
#include <ERRNO.H>    
#include <STRING.H>    
#include <SYS un.h>    
#include <SYS time.h>    
#include <SYS ioctl.h>    
#include <UNISTD.H>    
#include <NETINET in.h>    
#define SERVPORT 3338    
#define NEWPORT  3333    
#define BACKLOG 10    
#define MAX_CONNECTED_NO 10    
#define MAXDATASIZE 100    
int main()   
{   
    struct sockaddr_in server_sockaddr,client_sockaddr;   
    int sin_size,recvbytes;   
    fd_set readfd;   
    fd_set writefd;   
    int sockfd,client_fd,sockfd2, client_fd2;   
    char buf[MAXDATASIZE];   
    char buf2[MAXDATASIZE];   
   
    if((sockfd = socket(AF_INET,SOCK_STREAM,0))==-1){   
        perror("socket");   
        exit(1);   
    }   
    printf("socket success!,sockfd=%d\n",sockfd);   
   
    if((sockfd2 = socket(AF_INET,SOCK_STREAM,0))==-1){   
        perror("socket");   
        exit(1);   
    }   
    printf("socket success!,sockfd=%d\n",sockfd2);   
   
    //int n=1;    
    //setsockopt(sockfd, SOL_SOCKET,SO_REUSEADDR, &n, sizeof(n));    
   
    server_sockaddr.sin_family=AF_INET;   
    server_sockaddr.sin_port=htons(NEWPORT);   
    server_sockaddr.sin_addr.s_addr=INADDR_ANY;   
    bzero(&(server_sockaddr.sin_zero),8);   
    if(bind(sockfd2,(struct sockaddr *)&server_sockaddr,sizeof(struct sockaddr))==-1){   
        perror("bind");   
        exit(1);   
    }   
    printf("bind success!\n");   
   
       
   
    server_sockaddr.sin_family=AF_INET;   
    server_sockaddr.sin_port=htons(SERVPORT);   
    server_sockaddr.sin_addr.s_addr=INADDR_ANY;   
    bzero(&(server_sockaddr.sin_zero),8);   
    if(bind(sockfd,(struct sockaddr *)&server_sockaddr,sizeof(struct sockaddr))==-1){   
        perror("bind");   
        exit(1);   
    }   
    printf("bind success!\n");   
   
    if(listen(sockfd,BACKLOG)==-1){   
        perror("listen");   
        exit(1);   
    }   
    if(listen(sockfd2,BACKLOG)==-1){   
        perror("listen");   
        exit(1);   
    }   
       
    printf("listening....\n");   
/*將調用socket函數的描述符作為文件描述符*/   
    FD_ZERO(&readfd);   
    FD_SET(sockfd,&readfd);   
    FD_SET(sockfd2,&readfd);   
   
    while(1){   
    sin_size=sizeof(struct sockaddr_in);   
/*調用select函數*/   
    if(select(MAX_CONNECTED_NO,&readfd,NULL,NULL,(struct timeval *)0)>0){   
        if(FD_ISSET(sockfd,&readfd)>0){   
            if((client_fd=accept(sockfd,(struct sockaddr *)&client_sockaddr,&sin_size))==-1){   
                perror("accept");   
                exit(1);   
            }   
            if(read(client_fd,buf,MAXDATASIZE)<0){   
                perror("read");   
                exit(1);   
            }   
            printf("received a connection :%s\n",buf);   
           
            close(client_fd);   
           }   
   
           if(FD_ISSET(sockfd2,&readfd)>0){   
            if((client_fd2=accept(sockfd2,(struct sockaddr *)&client_sockaddr,&sin_size))==-1){   
                perror("accept");   
                exit(1);   
            }   
            if(read(client_fd2,buf,MAXDATASIZE)<0){   
                perror("read");   
                exit(1);   
            }   
            printf("received a connection :%s\n",buf);   
           
            close(client_fd2);   
           }   
        }   
    }/*while*/   
}