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10
if(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] = &#39;/0&#39;;
printf("Recive from server:%s",buf);
//关闭socket
close(sockfd);

return 0;
}