linux listen 什么意思

#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <string.h>#include <sys/types.h>#include <netinet/in.h>#include <sys/socket.h>#include <sys/wait.h>int main(){int sockfd,new_fd;struct sockaddr_in my_addr;struct sockaddr_in their_addr;int sin_size;//建立TCP套接口if((sockfd = socket(AF_INET,SOCK_STREAM,0))==-1){printf("create socket error");perror("socket");exit(1);}//初始化结构体，并绑定2323端口my_addr.sin_family = AF_INET;my_addr.sin_port = htons(2323);my_addr.sin_addr.s_addr = INADDR_ANY;bzero(&(my_addr.sin_zero),8);//绑定套接口if(bind(sockfd,(struct sockaddr *)&my_addr,sizeof(struct sockaddr))==-1){perror("bind socket error");exit(1);}//创建监听套接口  监听队列长度为10if(listen(sockfd,10)==-1){perror("listen");exit(1);}//等待连接while(1){sin_size = sizeof(struct sockaddr_in);printf("server is run./n");//如果建立连接，将产生一个全新的套接字if((new_fd = accept(sockfd,(struct sockaddr *)&their_addr,&sin_size))==-1){perror("accept");exit(1);}printf("accept success./n");//生成一个子进程来完成和客户端的会话，父进程继续监听if(!fork()){printf("create new thred success./n");//读取客户端发来的信息int numbytes;char buff[256];memset(buff,0,256);if((numbytes = recv(new_fd,buff,sizeof(buff),0))==-1){perror("recv");exit(1);}printf("%s",buff);//将从客户端接收到的信息再发回客户端if(send(new_fd,buff,strlen(buff),0)==-1)perror("send");close(new_fd);exit(0);}close(new_fd);}close(sockfd);}#include <stdio.h>#include <stdlib.h>#include <string.h>#include <netdb.h>#include <sys/types.h>#include <sys/socket.h>int main(int argc,char *argv[]){int sockfd,numbytes;char buf[100];struct sockaddr_in their_addr;//int i = 0;//将基本名字和地址转换//he = gethostbyname(argv[1]);//建立一个TCP套接口if((sockfd = socket(AF_INET,SOCK_STREAM,0))==-1){perror("socket");printf("create socket error.建立一个TCP套接口失败");exit(1);}//初始化结构体，连接到服务器的2323端口their_addr.sin_family = AF_INET;their_addr.sin_port = htons(2323);// their_addr.sin_addr = *((struct in_addr *)he->h_addr);inet_aton( "127.0.0.1", &their_addr.sin_addr );bzero(&(their_addr.sin_zero),8);//和服务器建立连接if(connect(sockfd,(struct sockaddr *)&their_addr,sizeof(struct sockaddr))==-1){perror("connect");exit(1);}//向服务器发送数据if(send(sockfd,"hello!socket.",6,0)==-1){perror("send");exit(1);}//接受从服务器返回的信息if((numbytes = recv(sockfd,buf,100,0))==-1){perror("recv");exit(1);}buf[numbytes] = '/0';printf("Recive from server:%s",buf);//关闭socketclose(sockfd);return 0;}