Linux 网络应用开发（二）之socket编程

socket编程例程

 本例程讲解一个socket网络编程的一个简单例子!

/*server.c*/#include<sys/types.h>#include<sys/socket.h>#include<stdio.h>#include<stdlib.h>#include<errno.h>#include<string.h>#include<unistd.h>#include<netinet/in.h>#define PORT 4321#define BUFFER_SIZE 1024#define MAX_COMN_NUM 5int main(){   struct sockaddr_in server_sockaddr,client_sockaddr;   int client_fd;   char buf[BUFFER_SIZE];   int sin_size,recvbytes;   int sockfd=socket(AF_INET,SOCK_STREAM,0);   if(sockfd==-1)   {     perror("socket");     exit(1);   }   printf("Socket id=%d\n",sockfd);   server_sockaddr.sin_family=AF_INET;   server_sockaddr.sin_port=htons(PORT);   server_sockaddr.sin_addr.s_addr=INADDR_ANY;   bzero(&(server_sockaddr.sin_zero),8);   int i=1;   setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&i,sizeof(i));   if(bind(sockfd,(struct sockaddr *)&server_sockaddr,sizeof(struct sockaddr))==-1)   {     perror("bind");     exit(1);   }   printf("bind success\n");   if(listen(sockfd,MAX_COMN_NUM)==-1)   {     perror("listen");     exit(1);   }   printf("Listening.....\n");   if((client_fd=accept(sockfd,(struct sockaddr *)&client_sockaddr,&sin_size))==-1)   {     perror("accept");     exit(1);   }   memset(buf,0,sizeof(buf));   if((recvbytes=recv(client_fd,buf,BUFFER_SIZE,0))==-1)   {     perror("recv");     exit(1);   }   printf("received a message: %s\n",buf);   close(sockfd);   exit(0);}/*client.c*/#include<stdio.h>#include<stdlib.h>#include<errno.h>#include<string.h>#include<netdb.h>#include<sys/types.h>#include<netinet/in.h>#include<sys/socket.h>#define PORT 4321#define BUFFER_SIZE 1024int main(int argc,char *argv[]){  int sockfd,sendbytes;  char buf[BUFFER_SIZE];  struct hostent *host;  struct sockaddr_in serv_addr;    if(argc<3)  {    fprintf(stderr,"USAGE:./client Hostname Text\n");    exit(1);  }  if((host=gethostbyname(argv[1]))==NULL)  {    perror("gethostbyname");    exit(1);  }  memset(buf,0,sizeof(buf));  sprintf(buf,"%s",argv[2]);  if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1)   {     perror("socket");     exit(1);   }   serv_addr.sin_family=AF_INET;   serv_addr.sin_port=htons(PORT);   serv_addr.sin_addr=*((struct in_addr *)host->h_addr);   bzero(&(serv_addr.sin_zero),8);   if(connect(sockfd,(struct sockaddr *)&serv_addr,sizeof(struct sockaddr))==-1)   {    perror("connect");    exit(1);   }   if((sendbytes=send(sockfd,buf,strlen(buf),0))==-1)   {    perror("send");    exit(1);   }   close(sockfd);   exit(0);}