text: /*************************************************************************
    > File Name: getIPInfo.c
    > Author: xgod
    > Mail: xgod@163.com 
    > Created Time: Mon 08 May 2017 05:48:15 PM CST
   ************************************************************************/
  
  #include <stdio.h>
  #include <unistd.h>
  #include <string.h> /* for strncpy */
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <sys/ioctl.h>
  #include <netinet/in.h>
  #include <net/if.h>
  #include <arpa/inet.h>
  
  int main(int argc, char* argv[])
  { 
  	int fd; 
  	struct ifreq ifr; 
  	fd = socket(AF_INET, SOCK_DGRAM, 0); /* I want to get an IPv4 IP address */ 
  	ifr.ifr_addr.sa_family = AF_INET; /* I want IP address attached to "eth0" */ 
  	strncpy(ifr.ifr_name, "eth0", IFNAMSIZ-1); 
  
  	ioctl(fd, SIOCGIFADDR, &ifr); 
  
  	close(fd); /* display result */ 
  
  	printf("%s\n", inet_ntoa(((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr)); 
  	return 0;
  }
  