fcntl.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 <sys/wait.h>
#include <sys/un.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <netinet/in.h>
#include <fcntl.h>
#define  PORT 3333
#define  BACKLOG 10
#define  MAX_CONNECTED_NO 10
#define  MAXDATASIZE 100

main()
{
  struct sockaddr_in addr,client_addr;
  int sin_size,recvbytes,flags;
  int sockfd,client_fd;
  char buf[MAXDATASIZE];
  if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1){
    perror("socket");
    exit(1);
  }
  printf("socket success!,sockfd=%d\n",sockfd);

  addr.sin_family=AF_INET;
  addr.sin_port=htons(PORT);
  addr.sin_addr.s_addr=INADDR_ANY;
  bzero(&(addr.sin_zero),8);

  if(bind(sockfd,(struct sockaddr *)&addr,sizeof(struct sockaddr))==-1)
{
  perror("bind");
  exit(1);  
  }
  printf("bind success!\n");

   if(listen(sockfd,BACKLOG)==-1)
{
  perror("listen");
  exit(1);  
  }
  printf("listening.......\n");

/*调用vfcntl函数设置非阻塞参数*/
if((flags=fcntl(sockfd,F_SETFL,0))<0)
     perror("fcntl F_SETFL");
     flags |=O_NONBLOCK;
     if(fcntl(sockfd,F_SETFL,flags)<0)
     perror("fcntl");
     while(1){
       sin_size=sizeof(struct sockaddr_in);  
   if((client_fd=accept(sockfd,(struct sockaddr *)&client_addr,&sin_size))==-1)
{
  perror("accept");
  exit(1);  
  }

   if((recvbytes=recv(client_fd,buf,MAXDATASIZE,0))==-1)
{
  perror("recv");
  exit(1);  
  }
   if((read(client_fd,buf,MAXDATASIZE))==-1)
{
  perror("read");
  exit(1);  
  }
  printf("received a connection:%s\n",buf);
  
  close(client_fd);
exit(1);
}/*while*/
}