client.c

linux 下的服务端和客户端连接

#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <netinet/in.h>
#include <netdb.h>
#define  PORT 3333
#define  MAXDATASIZE 100

main(int argc,char *argv[])
{
  int sockfd,sendbytes;
  char buf[MAXDATASIZE];
  struct hostent *host;
  struct sockaddr_in serv_addr;

   if(argc<2)
{
  fprintf(stderr,"please enter the server's hostname\n");
  exit(1);  
  }

   if((host=gethostbyname(argv[1]))==NULL)
{
  perror("gethostbyname");
  exit(1);  
  }

  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,"peims nihao",15,0))==-1)
{
  perror("send");
  exit(1);  
}
  close(sockfd);

}