Linux下select异步通讯如何实现

1.服务器端

/*select_server.c 2011.9.2 by yyg*/#include #include #include #include #include #include #include #include #include #include #include #include #include #define MAXBUF 1024int main(int argc,char **argv){  int sockfd,new_fd;  socklen_t len;  struct sockaddr_in my_addr,their_addr;  unsigned int myport,lisnum;  char buf[MAXBUF+1];  fd_set rfds;  struct timeval（argv[1]){    myport = atoi(argv[1]);  }  else    myport = 7838;  if(argv[2]){    lisnum = atoi(argv[2]);  }  else    lisnum =2;  if((sockfd = socket(PF_INET,SOCK_STREAM,0))== -1){    perror("socket");    exit(1);  }  bzero(&my_addr,sizeof(my_addr));  my_addr.sin_family = PF_INET;  my_addr.sin_port = htons(myport);  if(argv[3])    my_addr.sin_addr.s_addr = INADDR_ANY;    if(bind(sockfd,(struct sockaddr *)&my_addr,sizeof(struct sockaddr)) == -1){    perror("bind");    exit(1);  }    if(listen(sockfd, lisnum) == -1){    perror("listen");    exit(1);  }    while(1){    printf("\n----waiting for new connecting to start new char----\n");    len = sizeof(struct sockaddr);    if((new_fd = accept(sockfd,(struct sockaddr *)&their_addr,&len)) == -1){      perror("accept");      exit(errno);    }    else      printf("server:got connection from %s,port %d,socked %d\n",\        inet_ntoa(their_addr.sin_addr),\        ntohs(their_addr.sin_port),new_fd);        /*开始处理每个新连接上的数据收发*/    //printf("\n---ready to go.now you can chatting...input enter,then you can chat---\n");    while(1){      /*把集合清空*/      FD_ZERO(&rfds);      /*把标准输入句柄0加入到集合中*/      FD_SET(0,&rfds);      maxfd = 0;      /*把当前连接句柄new_fd加入到集合中*/      FD_SET(new_fd,&rfds);      if(new_fd > maxfd)        maxfd = new_fd;      /*设置最大等待时间*/      tv.tv_sec = 1;      tv.tv_usec = 0;      retval = select(maxfd+1,&rfds,NULL,NULL,&tv);      if(retval == -1){        printf("select error!%s\n",strerror(errno));        break;      }      else if(retval == 0){        //printf("no message come,user no press the button,please wait...\n");        continue;      }      else{        if(FD_ISSET(new_fd,&rfds)){        /*连接的socket 上有消息则接收并显示*/          bzero(buf,MAXBUF+1);          /*接收对方发过来的消息，最多MAXBUF字节*/          len = recv(new_fd, buf, MAXBUF, 0);          if(len > 0)            printf("recv msg success:%s! %d bytes rcv.\n ",buf,len);          else{            if(len < 0){              printf("recv msg fail.the errno is:%d,error info is %s.\n",errno,strerror(errno));            }            else              printf("quit.\n");            break;          }        }// FD_ISSET = sockfd情况        if(FD_ISSET(0,&rfds)){          /*用户有输入了，则读取其内容并发送*/          bzero(buf, MAXBUF+1);          fgets(buf, MAXBUF, stdin);          if(!strncasecmp(buf, "quit", 4)){            printf("self request to quit the chating\n");            break;          }          /*发消息给服务器*/          len = send(new_fd, buf, strlen(buf)-1 , 0);          if(len quit)");    fflush(stdout);    bzero(buf,MAXBUF+1);    fgets(buf,MAXBUF,stdin);    if(!strncasecmp(buf,"no",2)){      printf("quit the chatting!\n");      break;    }    }/*外while*/  close(sockfd);  return 0;}

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2.客户端

/*select_client.c 2011.9.2 by yyg*/#include #include #include #include #include #include #include #include #include #include #include #include #include #define MAXBUF 1024int main(int argc,char **argv){  int sockfd,len;  struct sockaddr_in dest;  char buffer[MAXBUF+1];  fd_set rfds;  struct timeval（argc != 3){    printf("the param style wrong!\n");    exit(0);  }  /*创建一个socket用于tcp通信*/  if((sockfd = socket(AF_INET,SOCK_STREAM,0))  maxfd)      maxfd = sockfd;    /*设置最大等待时间*/    tv.tv_sec = 1;    tv.tv_usec = 0;    /*开始等待*/    retval = select(maxfd+1,&rfds,NULL,NULL,&tv);    if(retval == -1){      printf("select error,quit!\n");      break;    }else if(retval == 0){      continue;    }else{      if(FD_ISSET(sockfd,&rfds)){        /*连接的socket 上有消息则接收并显示*/        bzero(buffer,MAXBUF+1);        /*接收对方发过来的消息，最多MAXBUF字节*/        len = recv(sockfd, buffer, MAXBUF, 0);        if(len > 0)          printf("recv msg success:%s! %d bytes rcv.\n ",buffer,len);        else{          if(len < 0){            printf("recv msg fail.the errno is:%d,error info is %s.\n",errno,strerror(errno));          }          else            printf("quit.\n");          break;        }      }// FD_ISSET = sockfd情况      if(FD_ISSET(0,&rfds)){        /*用户有输入了，则读取其内容并发送*/        bzero(buffer, MAXBUF+1);        fgets(buffer, MAXBUF, stdin);        if(!strncasecmp(buffer, "quit", 4)){          printf("self request to quit the chating\n");          break;        }        /*发消息给服务器*/        len = send(sockfd, buffer, strlen(buffer)-1 , 0);        if(len < 0){          printf("mgs:%s send fail!errno is:%d,error info is:%s\n", buffer, errno, strerror(errno));          break;        }else{          printf("msg: %s\t send success, send %d bytes!\n", buffer, len);        }      }//FD_ISSET = 0          }//select 处理结束  }//处理聊天的while 循环  /*关闭连接*/  close(sockfd);  return 0;}

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运行结果：

终端1：服务器端

[root@localhost net]# ./select_server 7838----waiting for new connecting to start new char----server:got connection from 172.31.100.236,port 59462,socked 4recv msg success:kfldsjfk! 8 bytes rcv.456354 msg: 456354         send success, send 6 bytes!recv msg success:453455! 6 bytes rcv.

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终端2：客户端

[root@localhost net]#  ./select_client 172.31.100.236 7838---ready to chatting...---kfldsjfkmsg: kfldsjfk         send success, send 8 bytes!recv msg success:456354! 6 bytes rcv.453455 msg: 453455         send success, send 6 bytes!

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