C program to find IP address using ioctl() system call.

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<unistd.h>
#include<errno.h>
#include<arpa/inet.h>
#include<netinet/in.h>
#include<sys/socket.h>
#include<sys/ioctl.h>
#include<sys/types.h>
#include<net/if.h>
/**
+++++++++++++++++++++++++++++++
Program:- Find IP address using ioctl
+++++++++++++++++++++++++++++++
Author:- Surendra S.Patil
+++++++++++++++++++++++++++++++
I/P:- interface name ex:- “eth0 “
+++++++++++++++++++++++++++++++
O/P:- Ip address (192.168.2.2)
+++++++++++++++++++++++++++++++
*/
int main()
{
  int sock_fd;
  struct ifreq interface;
  /* create socket and get socket descriptor */
  sock_fd = socket(AF_INET,SOCK_DGRAM,0);
 if (-1 == sock_fd) {
  fprintf(stderr,”errno:- %d :- %s”,errno,strerror(errno));
  exit(EXIT_FAILURE);
}
 /* copy the interface name */
  strcpy(interface.ifr_name,”eth0″);
 if(-1 == ioctl(sock_fd,SIOCGIFADDR,&interface)) {
  fprintf(stderr,”errno:- %d :- %s”,errno,strerror(errno));
  exit(EXIT_FAILURE);
  }
 printf(“Interface = %s\n IP Address = %s\n”,interface.ifr_name,
  inet_ntoa(((struct sockaddr_in *)&interface.ifr_addr)->sin_addr));
 close(sock_fd);
  exit(EXIT_SUCCESS); 
}

Run the program:-