/* Convert an IP address into its fully qualified domain name. */
#include <stdio.h>
#include <stdlib.h>
#include <netdb.h>

int main(int argc, char **argv)
{
	in_addr_t ip = inet_addr("131.211.17.1");
	struct hostent *entry;

	if ((int)ip == -1) {
		fprintf(stderr, "%s: bad argument to inet_addr\n", argv[0]);
		return EXIT_FAILURE;
	}

	entry = gethostbyaddr((char *)&ip, sizeof ip, AF_INET);
	if (entry == NULL) {
		fprintf(stderr, "%s: h_errno == %d\n", argv[0], h_errno);
		return EXIT_FAILURE;
	}

	printf("%s\n", entry->h_name);
	return EXIT_SUCCESS;
}