Name server IP of linux machine using C language

Question

I have to get name server IP of my system using C language.I am using Linux machine.

I have tried.

#include <stdio.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>
 #include <sys/types.h>
#include <sys/param.h>
#include <sys/cdefs.h>

int main()
{
int res_init(void);
printf("_res.nscount %d\n",_res.nscount);
//printf("_res.nsaddr_list[0] %s\n",_res.nsaddr_list[0]);
return 0;
}

But I am getting _res.nscount as 0.Am I doing anything wrong?

http://stackoverflow.com/questions/17909401/linux-c-get-default-interfaces-ip-address — mkjasinski, Feb 07 '14 at 12:44
What do you have in `/etc/resolv.conf` ? Add `cat /etc/resolv.conf ` to your question. — , Feb 07 '14 at 12:58

score 4 · Accepted Answer · answered Feb 07 '14 at 13:26

You declared res_init() instead of calling it. Try:

Int main() 
{
  res_init();
  /* ... */

However, nsaddr_list[0] isn't a string, so you won't be able to print it with printf("%s"). You'll have to use inet_ntoa() or similar to convert its sin_addr.s_addr value to a printable string.

Name server IP of linux machine using C language

1 Answers1