unsigned long long 就个什么东西？64位？有代码，有真相，请进

C/C++ code

/*unsgn_pow.c */unsigned long long unsgn_pow(unsigned int x,unsigned int y){  unsigned long long res=1;  if(y==0)    {      res=1;    }  else    {      if(y==1)a      {    res=x;      }      else      {    res=x*unsgn_pow(x,y-1);      }    }  return res;}

C/C++ code

/*pow_test.c*/#include <stdio.h>#include <stdlib.h>int main(int argc,char *argv[]){  unsigned int x,y;  unsigned long long res;  if((argc<3)||(sscanf(argv[1],"%u",&x)!=1)||(sscanf(argv[2],"%u",&y)!=1))    {      printf("Usage:pow base exponet\n ");      exit(1);    }  res=unsgn_pow(x,y);  printf("%u ^ %u= %u\n",x,y,res);  exit(0);}

目的就将unsgn_pow.c做成一个静态链接库，在UBUNTU 用GCC4.6.1进行编译，出现一下错误，是什么原因呢
root@jsj-virtual-machine:~/workspace# ar rcsv libpow.a unsgn_pow.o
r - unsgn_pow.o
root@jsj-virtual-machine:~/workspace# gcc -o pow_test pow_test.c -L. -lpow
pow_test.c: 在函数‘main’中:
pow_test.c:13:3: 警告： 格式 ‘%u’ expects argument of type ‘unsigned int’, but argument 4 has type ‘long long unsigned int’ [-Wformat]



[解决办法]
应该是%llu
[解决办法]
%llu