michael@x071:[/home/michael]ls -lia /tmp | head
total 287464
    2 drwxrwxrwt 54 bin      bin       36864 Jan 22 13:35 .
    2 drwxr-xr-x 39 root     system     4096 Jan  5 12:27 ..
    5 drwxrwxrwt  2 root     system      256 May  8  2013 .X11-unix
    6 -rw-r-----  1 root     system        0 May 23  2014 .ahafs.out.michael.10223652
    7 -rw-r-----  1 root     system        0 May 23  2014 .ahafs.out.michael.9502870
    8 -r--r--r--  1 root     system       25 Jun  9  2013 .aix_ISMP_lock____.save
    9 drwxrwxrwt  3 root     system     4096 Dec 27 12:15 .com_ibm_tools_attach
   62 -rw-r--r--  1 root     system     3124 Dec 27 11:21 .ctinst.log
   63 -rw-r-----  1 michael  felt       2578 Aug 16  2013 .htaccess

michael@x071:[/home/michael]od -dc /tmp | head -20
0000000       2   11776       0       0       0       0       0       0
          002   .
0000020       2   11822       0       0       0       0       0       0
          002   .   .
0000040   32848   11895   28530   27492   26994   11825   13109   13878
        200   P   .   w   o   r   k   d   i   r   .   1   3   5   6   6
0000060       5   11864   12593   11637   28265   30720       0       0
          005   .   X   1   1   -   u   n   i   x
0000100       6   11873   26721   26227   11887   30068   11885   26979
          006   .   a   h   a   f   s   .   o   u   t   .   m   i   c
0000120       7   11873   26721   26227   11887   30068   11885   26979
           a   .   a   h   a   f   s   .   o   u   t   .   m   i   c
0000140       8   11873   27000   24393   21325   20575   27759   25451
           b   .   a   i   x   _   I   S   M   P   _   l   o   c   k
0000160       9   11875   28525   24425   25197   24436   28527   27763
           t   .   c   o   m   _   i   b   m   _   t   o   o   l   s
0000200      62   11875   29801   28275   29742   27759   26368       0
            >   .   c   t   i   n   s   t   .   l   o   g
0000220      63   11880   29793   25443   25971   29440       0       0
            ?   .   h   t   a   c   c   e   s   s

michael@x067:~$ od -dc /tmp|head
od: /tmp: read error: Is a directory
0000000

#define _D_NAME_MAX 255

struct  dirent {
        __ulong64_t     d_offset;       /* real off after this entry */
        ino_t           d_ino;          /* inode number of entry */
        ushort_t        d_reclen;       /* length of this record */
        ushort_t        d_namlen;       /* length of string in d_name */
        char            d_name[_D_NAME_MAX+1];  /* name must be no longer than this */
                                        /* redefine w/#define when name decided */
};

struct dirent
  {
#ifndef __USE_FILE_OFFSET64
    __ino_t d_ino;
    __off_t d_off;
#else
    __ino64_t d_ino;
    __off64_t d_off;
#endif
    unsigned short int d_reclen;
    unsigned char d_type;
    char d_name[256];           /* We must not include limits.h! */
  };

/usr/include/dirent.h:
/* This is the data type of directory stream objects.
   The actual structure is opaque to users.  */
typedef struct __dirstream DIR;

extern DIR *opendir (__const char *__name) __nonnull ((1));
...
/* Read a directory entry from DIRP.  Return a pointer to a `struct
   dirent' describing the entry, or NULL for EOF or error.  The
   storage returned may be overwritten by a later readdir call on the
   same DIR stream.

   If the Large File Support API is selected we have to use the
   appropriate interface.

   This function is a possible cancellation point and therefore not
   marked with __THROW.  */
#ifndef __USE_FILE_OFFSET64
extern struct dirent *readdir (DIR *__dirp) __nonnull ((1));
#else
# ifdef __REDIRECT
extern struct dirent *__REDIRECT (readdir, (DIR *__dirp), readdir64)
     __nonnull ((1));
# else
#  define readdir readdir64
# endif
#endif

#ifdef __USE_LARGEFILE64
extern struct dirent64 *readdir64 (DIR *__dirp) __nonnull ((1));
#endif

/*
 * Definitions for library routines operating on directories.
 */
typedef struct _dirdesc {
#ifdef _ALL_SOURCE
        int     dd_fd;          /* file descriptor of directory */
        blksize_t dd_blksize;   /* this filesystem's block size */
        char    *dd_buf;        /* malloc'd buffer depending of fs bsize */
        long    dd_size;        /* size of buffer */
        long    dd_flag;        /* private flags for readdir, unused */
        off_t   dd_loc;         /* logical(dirent) offset in  directory */
        off_t   dd_curoff;      /* real offset in directory corresponding
                                 * to dd_loc */
#else
        int     __dd_fd;                /* file descriptor of directory */
        blksize_t __dd_blksize; /* this filesystem's block size */
        char    *__dd_buf;      /* malloc'd buffer depending of fs bsize */
        long    __dd_size;      /* size of buffer */
        long    __dd_flag;      /* private flags for readdir, unused */
        off_t   __dd_loc;       /* logical(dirent) offset in  directory */
        off_t   __dd_curoff;    /* real offset in directory corresponding
                                 * to dd_loc */
#endif
#if defined(_THREAD_SAFE) && defined(_ALL_SOURCE)
        void    *dd_lock;       /* for inter-thread locking */
#endif

} DIR;

...

extern  DIR *opendir(const char *);
extern  struct dirent *readdir(DIR *);