结构体DIR和dirent

1.存储目录中的文件信息（文件名、扩展名等等）#include <dirent.h>

struct dirent{   long d_ino; /* inode number 索引节点号 */  

 off_t d_off; /* offset to this dirent 在目录文件中的偏移 */   

unsigned short d_reclen; /* length of this d_name 文件名长 */  

 unsigned char d_type; /* the type of d_name 文件类型 */    

char d_name [NAME_MAX+1]; /* file name (null-terminated) 文件名，最长255字符 */

}

2.struct __dirstream
   {
void *__fd; /* `struct hurd_fd' pointer for descriptor.   */
char *__data; /* Directory block.   */
int __entry_data; /* Entry number `__data' corresponds to.   */
char *__ptr; /* Current pointer into the block.   */
int __entry_ptr; /* Entry number `__ptr' corresponds to.   */
size_t __allocation; /* Space allocated for the block.   */
size_t __size; /* Total valid data in the block.   */
__libc_lock_define (, __lock) /* Mutex lock for this structure.   */
   };

typedef struct __dirstream DIR;