linux 下的socket 客户端开发

/*
#define EXIT -1
#define USER  1  
#define MSG   2
#define OK    3
#define CMSGLEN 100


struct CLIENTMSG{
int OP;
char username[20];
char buf[CMSGLEN];
};
*/
#include"stdio.h"
#include"stdlib.h"
#include"sys/stat.h"
#include"sys/types.h"
#include"netinet/in.h"
#include"string.h"
#include"clientmsg.h"
int main()
{


int fd;
int port=123345;
char ip[20]="127.0.0.1";
    char globalname[20];
    //定义结构体CLIENTMSG  ,负责向服务器发送数据
struct CLIENTMSG *sendmsg;
    //定义结构体CLIENTMSG  ,负责接收来自服务器的数据
struct CLIENTMSG *recvmsg;


//输入服务器ip
    printf("please enter the server ip:\n"); scanf("%s",&ip);
//输入服务器端口
    printf("please enter the server port:\n"); scanf("%d",&port);


//定义结构体地址
struct sockaddr_in server;
server.sin_port=htons(port);
server.sin_family=inet_addr(ip);
server.sin_addr.s_addr=INADDR_ANY;
    
//  1. socket
if(-1== (fd=(socket(AF_INET,SOCK_STREAM,0))))
{
perror("socket error");
exit(1);
}
    //  2. connect
    socklen_t  len = sizeof(server);
if(-1==(connect(fd,(struct sockaddr*)&server,len)))
{
perror("connect error");
exit(1);
}
    
struct CLIENTMSG *tempmsg;
char tempbuf[CMSGLEN];
tempmsg=(struct CLIENTMSG*)malloc(sizeof(struct CLIENTMSG));


if(-1==(read(fd,tempbuf,sizeof(tempbuf))))
{
perror("read error");
exit(1);
}
   
memcpy(tempmsg,tempbuf,sizeof(tempbuf));
     if(tempmsg->OP==EXIT)
{
       printf("server is refuse,maybe the client is full\n");
  exit(1);
}
else  if(tempmsg->OP==OK)
{
printf("%s\n",tempmsg->buf);
memset(tempmsg,0,sizeof(tempmsg));
scanf("%s",tempmsg->username);
strcpy(globalname,tempmsg->username);
tempmsg->OP=USER;
strcpy(tempmsg->buf,"NULL");
    memcpy(tempbuf,tempmsg,sizeof(tempmsg));
write(fd,tempbuf,sizeof(tempbuf));


     }




    //  4. 创建子进程 ，负责接收数据
pid_t pid =fork();
   
// 5. 如果pid>0 ，说明在父进程，父进程负责向服务器发送数据
if(pid>0)
   {
       char sendbuf[CMSGLEN];
//5-1. 为结构体申请内存，避免内存溢出
     sendmsg = (struct CLIENTMSG*)malloc(sizeof(struct CLIENTMSG));
     //5-2.   while 循环向服务器发送数据
  while(1)
 {
      
memset(sendmsg,0,sizeof(sendmsg));
bzero(sendbuf,sizeof(sendbuf));
        strcpy(sendmsg->username,globalname);        
printf("please input your message:\n");scanf("%s",sendmsg->buf);
        sendmsg->OP=MSG;
memcpy(sendbuf,sendmsg,sizeof(sendmsg));
write(fd,sendbuf,sizeof(sendbuf));
       
        if(!strcpy(sendbuf,"bye"))
   {
 break;
}
 }




  wait();
 close(fd);
   }


   // 6. 如果pid＝＝0，说明在子进程,子进程负责接收服务器传来的的数据
if(pid==0)
{
char recvbuf[CMSGLEN];
  //6-1. 为结构体申请内存，避免内存溢出
       recvmsg = (struct CLIENTMSG*)malloc(sizeof(struct CLIENTMSG));
  //6-2. while  循环接收来自服务器的数据
      while(1)
 {


   //6-3. 将结构体清空
   memset(recvmsg,0,sizeof(recvmsg));
        bzero(recvbuf,sizeof(recvbuf));
         if(-1==(read(fd,recvbuf,sizeof(recvbuf))))
{
perror("read error");
}
 
memcpy(recvmsg,recvbuf,sizeof(recvbuf));
if(recvmsg->OP==EXIT)
{
   
printf("%s\n",recvmsg->buf);
break;
}
printf("%s\n",recvmsg->buf);
 
 }


}


    // while 退出，关闭socket
return 0;
}

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