getaddrinfo.c

getaddrinfo.c

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main()
{
 char *hostname = "www.softether.com";
 struct addrinfo hints, *res;
 struct in_addr addr;
 int err;
 char str[INET_ADDRSTRLEN];

 memset(&hints, 0, sizeof(hints));
 hints.ai_family = AF_UNSPEC;
 hints.ai_flags = AI_ALL | AI_ADDRCONFIG | AI_V4MAPPED;

 if ((err = getaddrinfo(hostname, NULL, &hints, &res)) != 0) {
   printf("error %s (%d)\n", gai_strerror(err), err);
   return 1;
 }

 addr.s_addr = ((struct sockaddr_in *)(res->ai_addr))->sin_addr.s_addr;
 inet_ntop(AF_INET, &addr.s_addr, str, INET_ADDRSTRLEN);

 printf("ip address : %s\n", str);

 freeaddrinfo(res);

 return 0;
}