gethostbyname, gethostbyaddr(原来百度叫shifen "十分?")

#include <unistd.h>
#include <netdb.h>
#include <sys/socket.h>
#include <stdio.h>
#include <string.h>

int main(int argc, char* argv[])
{
        struct hostent *info;
        int i;

        if((info = gethostbyname(argv[1])) == NULL)
        {
                if((info = gethostbyaddr(argv[1], strlen(argv[1]), AF_INET)) == NULL)
                {
                        printf("error : ./gethostby name|ip\n");
                        return 0;
                }
        }

        printf("h_name = %s\n", info->h_name);

        for(i = 0; info->h_aliases[i] != NULL; ++i)
                printf("h_aliases[%d] = %s\n", i,  info->h_aliases[i]);

        printf("h_addrtype = %d\n", info->h_addrtype);
        printf("h_length = %d\n", info->h_length);

        for(i = 0; info->h_addr_list[i] != NULL; ++i)
                printf("h_addr_list[%d] = %s\n",
                        i, inet_ntoa(*(struct in_addr *)(info->h_addr_list[i])));

        return 0;
}