It's from here,but fails when compiling:

int main(int argc, char **argv)
{
    struct hostent {
        char *h_name; // main name
        char **h_aliases; // alternative names (aliases)
        int h_addrtype; // address type (usually AF_INET)
        int h_length; // length of address (in octets)
        char **h_addr_list; // alternate addresses (in Network Byte Order)
    };
    #define h_addr h_addr_list[0] // First address of h_addr_list.


    struct hostent *info_stackoverflow;
    int i = 0;
    info_stackoverflow = gethostbyname( "www.stackoverflow.com" );
    printf("The IP address of %s is %s", 
           info_stackoverflow->h_name, 
           inet_ntoa( * ((struct in_addr *)info_stackoverflow->h_addr )));
    /* aliases */
    while( *(pc_ip->h_aliases + i) != NULL )
    {
        printf("\n\tAlias: %s", *(pc_ip->h_aliases + i) );
        i++;
    }
}