利用stat函数实现

int stat(const char *path, struct stat *buf)

我们来看程序

 
    8 #define N_BITS 3
    9 
   10 int main(int argc,char *argv[])
   11 {
   12   unsigned int i,mask = 0700;
   13   struct stat buff;
W> 14   static char *perm[] = {"---","--x","-w-","-wx","r--","r-x","rw-","rwx"};
   15   if(argc>1)
   16   {
   17     if((stat(argv[1],&buff)!=-1))
   18     {
   19       printf("permissions for %s\t",argv[1]);
   20       for(i = 3;i;--i)                                                                                  
   21       {                                             
   22         printf("%3s",perm[(buff.st_mode&mask)>>(i-1)*N_BITS]);
   23         mask>>=N_BITS;
   24       }                                       
   25       putchar('\n');              
   26     }                    
   27     else{                             
   28       perror(argv[1]);
   29       exit(EXIT_FAILURE);
   30                                                                  
   31     }                                                          
   32   }                                                     
   33   else{                                                                                                                                                                                  
   34     fprintf(stderr,"Usage:%s file_name\n",argv[0]);     
   35   }                                         
   36                                                                                                                                 
   37 return 0;           
   38 }

测试程序

运行程序

可以看到实现效果相同。