[thirdparty/man-pages.git] / man2 / readdir.2

.\" Copyright (C) 1995 Andries Brouwer (aeb@cwi.nl)
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\" 
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\" 
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" Written 11 June 1995 by Andries Brouwer <aeb@cwi.nl>
.\" Modified 22 July 1995 by Michael Chastain <mec@duracef.shout.net>:
.\"   In 1.3.X, returns only one entry each time; return value is different.
.\" Modified 2004-12-01, mtk, fixed headers listed in SYNOPSIS
.\"
.TH READDIR 2  1995-07-22 "Linux 1.3.6" "Linux Programmer's Manual"
.SH NAME
readdir \- read directory entry
.SH SYNOPSIS
.nf

.B #include <linux/types.h>
.B #include <linux/dirent.h>
.B #include <linux/unistd.h>
.B #include <errno.h>
.sp
.B _syscall3(int, readdir, uint, fd, struct dirent *, dirp, uint, count);
.sp
.BI "int readdir(unsigned int " fd ", struct dirent *" dirp ", unsigned int " count );
.fi
.SH DESCRIPTION
This is not the function you are interested in.
Look at
.BR readdir (3)
for the POSIX conforming C library interface.
This page documents the bare kernel system call interface,
which can change, and which is superseded by
.BR getdents (2).
.PP
.B readdir
reads one
.I dirent
structure from the directory
pointed at by
.I fd
into the memory area pointed to by
.IR dirp .
The parameter 
.I count
is ignored; at most one dirent structure is read.
.PP
The
.I dirent
structure is declared as follows:
.PP
.RS
.nf
struct dirent
{
    long d_ino;                 /* inode number */
    off_t d_off;                /* offset to this \fIdirent\fP */
    unsigned short d_reclen;    /* length of this \fId_name\fP */
    char d_name [NAME_MAX+1];   /* file name (null-terminated) */
}
.fi
.RE
.PP
.I d_ino
is an inode number.
.I d_off
is the distance from the start of the directory to this
.IR dirent .
.I d_reclen
is the size of
.IR d_name,
not counting the null terminator.
.I d_name
is a null-terminated file name.
.PP
.SH "RETURN VALUE"
On success, 1 is returned.
On end of directory, 0 is returned.
On error, \-1 is returned, and
.I errno
is set appropriately.
.SH ERRORS
.TP
.B EBADF
Invalid file descriptor
.IR fd .
.TP
.B EFAULT
Argument points outside the calling process's address space.
.TP
.B EINVAL
Result buffer is too small.
.TP
.B ENOENT
No such directory.
.TP
.B ENOTDIR
File descriptor does not refer to a directory.
.SH "CONFORMING TO"
This system call is Linux specific.
.SH "SEE ALSO"
.BR getdents (2),
.BR readdir (3)
Commit	Line	Data
fea681da MK	1	.\" Copyright (C) 1995 Andries Brouwer (aeb@cwi.nl)
	2	.\"
	3	.\" Permission is granted to make and distribute verbatim copies of this
	4	.\" manual provided the copyright notice and this permission notice are
	5	.\" preserved on all copies.
	6	.\"
	7	.\" Permission is granted to copy and distribute modified versions of this
	8	.\" manual under the conditions for verbatim copying, provided that the
	9	.\" entire resulting derived work is distributed under the terms of a
	10	.\" permission notice identical to this one.
	11	.\"
	12	.\" Since the Linux kernel and libraries are constantly changing, this
	13	.\" manual page may be incorrect or out-of-date. The author(s) assume no
	14	.\" responsibility for errors or omissions, or for damages resulting from
	15	.\" the use of the information contained herein. The author(s) may not
	16	.\" have taken the same level of care in the production of this manual,
	17	.\" which is licensed free of charge, as they might when working
	18	.\" professionally.
	19	.\"
	20	.\" Formatted or processed versions of this manual, if unaccompanied by
	21	.\" the source, must acknowledge the copyright and authors of this work.
	22	.\"
	23	.\" Written 11 June 1995 by Andries Brouwer <aeb@cwi.nl>
	24	.\" Modified 22 July 1995 by Michael Chastain <mec@duracef.shout.net>:
	25	.\" In 1.3.X, returns only one entry each time; return value is different.
b4c0e1cb MK	26	.\" Modified 2004-12-01, mtk, fixed headers listed in SYNOPSIS
b4c0e1cb MK	27	.\"
fea681da MK	28	.TH READDIR 2 1995-07-22 "Linux 1.3.6" "Linux Programmer's Manual"
	29	.SH NAME
	30	readdir \- read directory entry
	31	.SH SYNOPSIS
	32	.nf
b4c0e1cb MK	33
b4c0e1cb MK	34	.B #include <linux/types.h>
fea681da MK	35	.B #include <linux/dirent.h>
fea681da MK	36	.B #include <linux/unistd.h>
b4c0e1cb	37	.B #include <errno.h>
fea681da MK	38	.sp
	39	.B _syscall3(int, readdir, uint, fd, struct dirent *, dirp, uint, count);
	40	.sp
	41	.BI "int readdir(unsigned int " fd ", struct dirent *" dirp ", unsigned int " count );
	42	.fi
	43	.SH DESCRIPTION
	44	This is not the function you are interested in.
	45	Look at
	46	.BR readdir (3)
	47	for the POSIX conforming C library interface.
	48	This page documents the bare kernel system call interface,
	49	which can change, and which is superseded by
	50	.BR getdents (2).
	51	.PP
	52	.B readdir
	53	reads one
	54	.I dirent
	55	structure from the directory
	56	pointed at by
	57	.I fd
	58	into the memory area pointed to by
	59	.IR dirp .
	60	The parameter
	61	.I count
	62	is ignored; at most one dirent structure is read.
	63	.PP
	64	The
	65	.I dirent
	66	structure is declared as follows:
	67	.PP
	68	.RS
	69	.nf
	70	struct dirent
	71	{
	72	long d_ino; /* inode number */
	73	off_t d_off; /* offset to this \fIdirent\fP */
	74	unsigned short d_reclen; /* length of this \fId_name\fP */
	75	char d_name [NAME_MAX+1]; /* file name (null-terminated) */
	76	}
	77	.fi
	78	.RE
	79	.PP
	80	.I d_ino
	81	is an inode number.
	82	.I d_off
	83	is the distance from the start of the directory to this
	84	.IR dirent .
	85	.I d_reclen
	86	is the size of
	87	.IR d_name,
	88	not counting the null terminator.
	89	.I d_name
	90	is a null-terminated file name.
	91	.PP
	92	.SH "RETURN VALUE"
	93	On success, 1 is returned.
	94	On end of directory, 0 is returned.
	95	On error, \-1 is returned, and
	96	.I errno
	97	is set appropriately.
	98	.SH ERRORS
	99	.TP
	100	.B EBADF
	101	Invalid file descriptor
102	.IR fd .
103	.TP
104	.B EFAULT
105	Argument points outside the calling process's address space.
106	.TP
107	.B EINVAL
108	Result buffer is too small.
109	.TP
110	.B ENOENT
111	No such directory.
112	.TP
113	.B ENOTDIR
114	File descriptor does not refer to a directory.
115	.SH "CONFORMING TO"
116	This system call is Linux specific.
117	.SH "SEE ALSO"
118	.BR getdents (2),
119	.BR readdir (3)