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ioctl_fat.2: d_ino, d_off, return value explained 

The fields d_ino and d_off of structure __fat_dirent are explained.

The different return values of VFAT_IOCTL_READDIR_BOTH and
VFAT_IOCTL_READDIR_SHORT are explained.

The usage of the return value in the example is corrected.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Heinrich Schuchardt 2015-02-06 23:10:38 +01:00 committed by Michael Kerrisk
parent 3b4f95709f
commit 432cdf0d7c
1 changed files with 46 additions and 8 deletions
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54
man2/ioctl_fat.2
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@ -157,25 +157,61 @@ struct __fat_dirent {
The first entry in the array is for the short filename.
The second entry is for the long filename.
.PP
Fields
.I d_ino
and
.I d_off
are only filled for long filenames.
Field
.I d_ino
holds the inode number of the directory.
Field
.I d_off
holds the offset of the file entry in the directory.
As these values are not available for short filenames, the user code should
simply ignore them.
.PP
The field
.I d_reclen
contains the length of the filename in the field
.IR d_name .
A length of 0 for the short filename signals that the end of the directory
has been reached.
.\" FIXME Missing here are explanations of the fileds ;d_ino' and 'd_off'
To keep backwards compatibility a length of 0 for the short filename signals
that the end of the directory has been reached.
The user code should rely on the return value to identify the end of the
directory.
If no long filename exists, field
.I d_reclen
is set to 0 and
.I d_name
is a character string of length 0 for the long filename.
.SH RETURN VALUE
On error, \-1 is returned, and
.I errno
is set to indicate the error.
.PP
For
.B VFAT_IOCTL_READDIR_BOTH
and
.B VFAT_IOCTL_READDIR_SHORT
a return value of 1 signals that a new directory entry has been read and
a return value of 0 signals that the end of the directory has been reached.
.SH ERRORS
.TP
.B ENOENT
This error is returned by
.B VFAT_IOCTL_READDIR_BOTH
and
.B VFAT_IOCTL_READDIR_SHORT
if the file descriptor
.I fd
refers to a removed, but still open directory.
.TP
.B ENOTDIR
This error is returned by
.B VFAT_IOCTL_READDIR_SHORT
.B VFAT_IOCTL_READDIR_BOTH
and
.B VFAT_IOCTL_READDIR_SHORT
if
if the file descriptor
.I fd
does not refer to a directory.
.TP
@ -431,10 +467,12 @@ main(int argc, char *argv[])
/*
* If an error occurs, the return value is \-1.
* If d_reclen is zero, the end of the directory
* list has been reached.
* If the end of the directory list has been reached,
* the return value is 0.
* For backward compatibility the end of the directory
* list is also signaled by d_reclen == 0.
*/
if (ret == \-1 || entry[0].d_reclen == 0)
if (ret < 1)
break;
/*