ser.c

socket 发送接收字符串

//file name : ser.c

#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> 

#define MYPORT 3999 //listening port
#define BACKLOG 10 //max connect requests

main() 
{ 
 int sock_fd,new_fd; //sock_fd：listening socket；new_fd：data socket
 struct sockaddr_in my_addr; // local adderss
 struct sockaddr_in their_addr; // client address
 int sin_size; //?
 if ((sock_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
 { 
  perror("socket creat error");
  exit(1); 
 } 
 my_addr.sin_family = AF_INET; 
 my_addr.sin_port = htons(MYPORT); 
 my_addr.sin_addr.s_addr = INADDR_ANY; 
 bzero(&(my_addr.sin_zero),8); 
 if( bind(sock_fd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1)
 { 
  perror("bind error"); 
  exit(1); 
 } 
 if (listen(sock_fd, BACKLOG) == -1)
 { 
  perror("listen error"); 
  exit(1); 
 } 
 while(1)
 { 
  sin_size = sizeof(struct sockaddr_in); 
  if ((new_fd = accept(sock_fd, (struct sockaddr *)&their_addr, &sin_size)) == -1)
  { 
   perror("accept error"); 
   continue; 
  } 
  printf("received a connection from: %s\n", inet_ntoa(their_addr.sin_addr)); 
  if (!fork()) //son p
  { 
  if (send(new_fd, "Hello, you are connected!\n", 26, 0) == -1)
   {
    perror("send error"); 
   }
   close(new_fd); 
   exit(0); 
  } 
  close(new_fd); 
  waitpid(-1,NULL,WNOHANG) > 0;
 } 
}