2.9BSD/usr/man/cat5/dir.5

DIR(5)              UNIX Programmer's Manual               DIR(5)

NAME
     dir - format of directories

SYNOPSIS
     #include <sys/dir.h>

DESCRIPTION
     A directory behaves exactly like an ordinary file, save that
     no user may write into a directory.  The fact that a file is
     a directory is indicated by a bit in the flag word of its
     i-node entry see, _f_i_l_s_y_s(5).  The structure of a directory
     entry as given in the include file is:

          #ifndef DIRSIZ
          #define DIRSIZ14
          #endif
          struct  direct
          {
                  ino_t d_ino;
                  char  d_name[DIRSIZ];
          };

     By convention, the first two entries in each directory are
     for `.' and `..'.  The first is an entry for the directory
     itself.  The second is for the parent directory.  The mean-
     ing of `..' is modified for the root directory of the master
     file system and for the root directories of removable file
     systems.  In the first case, there is no parent, and in the
     second, the parent will be relative to the mounted-on file.
     Therefore in both cases `..' has the same inode number as
     `.'.

SEE ALSO
     filsys(5)

Printed 4/30/83                                                 1