.TH DIR 5
.SH NAME
dir, dirent \- directory layout
.SH SYNOPSIS
.nf
.ft B
#include <sys/types.h>
#include <dirent.h>
.SH DESCRIPTION
The directories of the standard V1 and V2 file systems are arrays of the
following structure defined in <dirent.h>:
.PP
.nf
.ta +5n +15n +15n
struct _v7_direct {
	ino_t	d_ino;	/* I-node number */
	char	d_name[14];	/* Name of up to 14 characters */
};
.fi
.DT
.PP
The
.B d_ino
field is the inode number of the file named by
.BR d_name .
.B D_ino
is zero if the directory slot isn't allocated.  This number is the same as
.B st_ino
returned by
.BR stat (2)
unless the entry is mounted on.
.B D_name
is the name of up to 14 characters, null-terminated only if less then 14
in length.  Any character other than null or '\fB/\fP' is allowed.
.PP
The flex versions of the V1 and V2 file systems have the directory
layout defined by these two structures:
.PP
.nf
.ta +5n +15n +15n
struct _fl_direct {		/* First slot in an entry */
	ino_t	d_ino;
	unsigned char	d_extent;
	char	d_name[5];	/* The shortest name has length 4 */
};

	/* Name of length len needs _EXTENT(len) extra slots. */
#define _EXTENT(len)	(((len) + 3) >> 3)

struct dirent {		/* Largest entry (8 slots) */
	ino_t	d_ino;	/* I-node number */
	unsigned char	d_extent;	/* Extended with this many slots */
	char	d_name[61];	/* Null terminated name */
};
.fi
.DT
.PP
The
.B d_ino
and
.B d_name
fields are like before, except that
.B d_name
may contain a null-terminated name of up to 60 characters.  The
.B d_extent
field tells how many 8 byte slots follow the first slot to contain the
whole entry.  An entry is always fully contained within a directory
block of Minix native block size.
.PP
If you have to access directories at the low level then the way to find
out if the directory is flex or the old Version 7 type is to look at
.B d_extent
of the first slot.  This slot always contains the "\fB.\fP" entry, so
.B d_extent
is zero for flex, '\fB.\fP' for V7.
.PP
See
.BR directory (3)
for a portable way to access directories, _v7_direct and _fl_direct are not
even in the user's namespace.
.SH "SEE ALSO"
.BR directory (3).
.SH AUTHOR
Kees J. Bot (kjb@cs.vu.nl)