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dir(FP)


dir -- format of a directory

Syntax

#include <sys/fs/*dir.h>

#include <sys/fs/xxinode.h>

Description

A directory behaves like an ordinary file, except that no user may write into a directory. The fact that a file is a directory is indicated by a field in its inode (see filesystem(FP)). The structure of a directory is given in the include file corresponding to each supported filesystem:

File Filesystem architecture
dtdir.h DTFS (Desktop Filesystem, a compression filesystem)
hsdir.h HS (High Sierra), ISO9660 and RCKRDG (Rock Ridge)
htdir.h S51K (UNIX filesystem), HTFS (High Throughput Filesystem), EAFS (Enhanced ACER Fast Filesystem) and AFS (ACER Fast Filesystem)
dosdir.h DOS
xxinode.h XENIX

 +----------+--------------------------------+
 |File      | Filesystem architecture        |
 |dtdir.h   | DTFS (Desktop Filesystem, a    |
 |          | compression filesystem)        |
 |hsdir.h   | HS (High Sierra), ISO9660 and  |
 |          | RCKRDG (Rock Ridge)            |
 |htdir.h   | S51K (UNIX filesystem), HTFS   |
 |          | (High Throughput Filesystem),  |
 |          | EAFS (Enhanced ACER Fast       |
 |          | Filesystem) and AFS (ACER Fast |
 |          | Filesystem)                    |
 |dosdir.h  | DOS                            |
 |xxinode.h | XENIX                          |
 +----------+--------------------------------+
Due to the diversity of filesystem types (and hence directory structures), do not read the directory as a file using open(S) and read(S). Instead the opendir(S) and readdir(S) system calls should be used. These are provided to allow directories to be read in a way that is independent of filesystem structure.

By convention, the first two entries in each directory are``dot'' (.) and ``dotdot'' (..). The first is an entry for the directory itself. The second is for the parent directory. The meaning of dotdot is modified for the root directory of the master file system; there is no parent, so dotdot has the same meaning as dot.

When versioning is enabled under HTFS/DTFS and a directory is being read that has versioning enabled, the use of opendir( ) and readdir( ) may return entries for the versioned copies of files that have been modified. These are only returned if the SHOWVERSIONS environment variable has the value 1. The returned entries take the form filename;version. See undelete(C) for more details.

See also

filesystem(FP), opendir(S), undelete(C)
© 2003 File Formats for Programming (FP)
SCO OpenServer Release 5.0.7 -- 11 February 2003