[apple/xnu.git] / bsd / man / man2 / open.2

.\"	$NetBSD: open.2,v 1.8 1995/02/27 12:35:14 cgd Exp $
.\"
.\" Copyright (c) 1980, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)open.2	8.2 (Berkeley) 11/16/93
.\"
.Dd November 16, 1993
.Dt OPEN 2
.Os BSD 4
.Sh NAME
.Nm open
.Nd open or create a file for reading or writing
.Sh SYNOPSIS
.\" OH??? .Fd #include <sys/stat.h>
.Fd #include <fcntl.h>
.Ft int
.Fo open
.Fa "const char *path"
.Fa "int oflag"
.Fa "..."
.Fc
.Sh DESCRIPTION
The file name specified by
.Fa path
is opened
for reading and/or writing,
as specified by the argument
.Fa oflag ;
the file descriptor is returned to the calling process.
.Pp
The
.Fa oflag
argument may indicate that the file is to be
created if it does not exist (by specifying the
.Dv O_CREAT
flag).  In this case,
.Nm
requires a third argument
.Fa "mode_t mode" ;
the file is created with mode
.Fa mode
as described in
.Xr chmod 2
and modified by the process' umask value (see
.Xr umask 2 ) .
.Pp
The flags specified are formed by
.Em or Ns 'ing
the following values:
.Pp
.Bd -literal -offset indent -compact
O_RDONLY	open for reading only
O_WRONLY	open for writing only
O_RDWR		open for reading and writing
O_NONBLOCK	do not block on open or for data to become available
O_APPEND	append on each write
O_CREAT		create file if it does not exist
O_TRUNC		truncate size to 0
O_EXCL		error if O_CREAT and the file exists
O_SHLOCK	atomically obtain a shared lock
O_EXLOCK	atomically obtain an exclusive lock
O_NOFOLLOW	do not follow symlinks
O_SYMLINK	allow open of symlinks
.Ed
.Pp
Opening a file with
.Dv O_APPEND
set causes each write on the file to be appended to the end.  If
.Dv O_TRUNC
is specified and the
file exists, the file is truncated to zero length.
If
.Dv O_EXCL
is set with
.Dv O_CREAT
and the file already
exists,
.Fn open
returns an error.
This may be used to implement a simple exclusive-access locking mechanism.
If
.Dv O_EXCL
is set and the last component of the pathname is a symbolic link,
.Fn open
will fail even if the symbolic link points to a non-existent name.
.Pp
If the
.Dv O_NONBLOCK
flag is specified, do not wait for the device or file
to be ready or available.  If the
.Fn open
call would result
in the process being blocked for some reason
(e.g., waiting for carrier on a dialup line),
.Fn open
returns immediately.
This flag also has the effect of making all subsequent I/O
on the open file non-blocking.
.Pp
When opening a file, a lock with
.Xr flock 2
semantics can be obtained by setting
.Dv O_SHLOCK
for a shared lock, or
.Dv O_EXLOCK
for an exclusive lock.
If creating a file with
.Dv O_CREAT ,
the request for the lock will never fail
(provided that the underlying filesystem supports locking).
.Pp
If
.Dv O_NOFOLLOW
is used in the mask and the target file passed to
.Fn open
is a symbolic link then the
.Fn open
will fail.
.Pp
If
.Dv O_SYMLINK
is used in the mask and the target file passed to
.Fn open
is a symbolic link then the
.Fn open
will be for the symbolic link itself, not what it links to.
.Pp
If successful,
.Fn open
returns a non-negative integer, termed a file descriptor.
It returns -1 on failure.
The file pointer (used to mark the current position within the file)
is set to the beginning of the file.
.Pp
When a new file is created,
it is given the group of the directory which contains it.
.Pp
The new descriptor is set to remain open across
.Xr execve
system calls; see
.Xr close 2
and
.Xr fcntl 2 .
.Pp
The system imposes a limit on the number of file descriptors
that can be held open simultaneously by one process.
.Xr Getdtablesize 2
returns the current system limit.
.Sh RETURN VALUES
If successful,
.Fn open
returns a non-negative integer, termed a file descriptor.
It returns -1 on failure, and sets
.Va errno
to indicate the error.
.Sh ERRORS
The named file is opened unless:
.Bl -tag -width Er
.\" ===========
.It Bq Er EACCES
Search permission is denied for a component of the path prefix.
.\" ===========
.It Bq Er EACCES
The required permissions (for reading and/or writing)
are denied for the given flags.
.\" ===========
.It Bq Er EACCES
.Dv O_CREAT
is specified,
the file does not exist,
and the directory in which it is to be created
does not permit writing.
.\" ===========
.It Bq Er EACCES
.Dv O_TRUNC
is specified and write permission is denied.
.\" ===========
.It Bq Er EAGAIN
.Fa path
specifies the slave side of a locked pseudo-terminal device.
.\" ===========
.It Bq Er EDQUOT
.Dv O_CREAT
is specified,
the file does not exist,
and the directory in which the entry for the new file
is being placed cannot be extended because the
user's quota of disk blocks on the file system
containing the directory has been exhausted.
.\" ===========
.It Bq Er EDQUOT
.Dv O_CREAT
is specified,
the file does not exist,
and the user's quota of inodes on the file system
on which the file is being created has been exhausted.
.\" ===========
.It Bq Er EEXIST
.Dv O_CREAT
and
.Dv O_EXCL
are specified and the file exists.
.\" ===========
.It Bq Er EFAULT
.Fa Path
points outside the process's allocated address space.
.\" ===========
.It Bq Er EINTR
The
.Fn open
operation is interrupted by a signal.
.\" ===========
.It Bq Er EINVAL
The value of
.Fa oflag
is not valid.
.\" ===========
.It Bq Er EIO
An I/O error occurs while making the directory entry or
allocating the inode for
.Dv O_CREAT .
.\" ===========
.It Bq Er EISDIR
The named file is a directory, and the arguments specify
that it is to be opened for writing.
.\" ===========
.It Bq Er ELOOP
Too many symbolic links are encountered in translating the pathname.
This is taken to be indicative of a looping symbolic link.
.\" ===========
.It Bq Er EMFILE
The process has already reached its limit for open file descriptors.
.\" ===========
.It Bq Er ENAMETOOLONG
A component of a pathname exceeds
.Dv {NAME_MAX}
characters, or an entire path name exceeded 
.Dv {PATH_MAX}
characters.
.\" ===========
.It Bq Er ENFILE
The system file table is full.
.\" ===========
.It Bq Er ELOOP
.Dv O_NOFOLLOW
was specified and the target is a symbolic link.
.\" ===========
.It Bq Er ENOENT
.Dv O_CREAT
is not set and the named file does not exist.
.\" ===========
.It Bq Er ENOENT
A component of the path name that must exist does not exist.
.\" ===========
.It Bq Er ENOSPC
.Dv O_CREAT
is specified,
the file does not exist,
and the directory in which the entry for the new file is being placed
cannot be extended because there is no space left on the file
system containing the directory.
.\" ===========
.It Bq Er ENOSPC
.Dv O_CREAT
is specified,
the file does not exist,
and there are no free inodes on the file system on which the
file is being created.
.\" ===========
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.\" ===========
.It Bq Er ENXIO
The named file is a character-special or block-special file
and the device associated with this special file does not exist.
.\" ===========
.It Bq Er ENXIO
O_NONBLOCK and O_WRONLY are set, the file is a FIFO,
and no process has it open for reading.
.\" ===========
.It Bq Er EOPNOTSUPP
.Dv O_SHLOCK
or
.Dv O_EXLOCK
is specified, but the underlying filesystem does not support locking.
.\" ===========
.It Bq Er EOPNOTSUPP
An attempt is made to open a socket (not currently implemented).
.\" ===========
.It Bq Er EOVERFLOW
The named file is a regular file
and its size does not fit in an object of type off_t.
.\" ===========
.It Bq Er EROFS
The named file resides on a read-only file system,
and the file is to be modified.
.\" ===========
.It Bq Er ETXTBSY
The file is a pure procedure (shared text) file that is being
executed and the
.Fn open
call requests write access.
.El
.Sh COMPATIBILITY
.Fn open
on a terminal device (i.e., /dev/console)
will now make that device a controlling terminal for the process.
Use the O_NOCTTY flag to open a terminal device
without changing your controlling terminal.
.Sh SEE ALSO
.Xr chmod 2 ,
.Xr close 2 ,
.Xr dup 2 ,
.Xr getdtablesize 2 ,
.Xr lseek 2 ,
.Xr read 2 ,
.Xr umask 2 ,
.Xr write 2
.Sh HISTORY
An
.Fn open
function call appeared in 
.At v6 .
Commit	Line	Data
9bccf70c A	1	.\" $NetBSD: open.2,v 1.8 1995/02/27 12:35:14 cgd Exp $
	2	.\"
	3	.\" Copyright (c) 1980, 1991, 1993
	4	.\" The Regents of the University of California. All rights reserved.
	5	.\"
	6	.\" Redistribution and use in source and binary forms, with or without
	7	.\" modification, are permitted provided that the following conditions
	8	.\" are met:
	9	.\" 1. Redistributions of source code must retain the above copyright
	10	.\" notice, this list of conditions and the following disclaimer.
	11	.\" 2. Redistributions in binary form must reproduce the above copyright
	12	.\" notice, this list of conditions and the following disclaimer in the
	13	.\" documentation and/or other materials provided with the distribution.
	14	.\" 3. All advertising materials mentioning features or use of this software
	15	.\" must display the following acknowledgement:
	16	.\" This product includes software developed by the University of
	17	.\" California, Berkeley and its contributors.
	18	.\" 4. Neither the name of the University nor the names of its contributors
	19	.\" may be used to endorse or promote products derived from this software
	20	.\" without specific prior written permission.
	21	.\"
	22	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	23	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	24	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	25	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	26	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	27	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	28	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	29	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	30	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	31	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	32	.\" SUCH DAMAGE.
	33	.\"
	34	.\" @(#)open.2 8.2 (Berkeley) 11/16/93
	35	.\"
	36	.Dd November 16, 1993
	37	.Dt OPEN 2
	38	.Os BSD 4
	39	.Sh NAME
	40	.Nm open
	41	.Nd open or create a file for reading or writing
	42	.Sh SYNOPSIS
2d21ac55	43	.\" OH??? .Fd #include <sys/stat.h>
9bccf70c A	44	.Fd #include <fcntl.h>
9bccf70c A	45	.Ft int
2d21ac55 A	46	.Fo open
	47	.Fa "const char *path"
	48	.Fa "int oflag"
	49	.Fa "..."
	50	.Fc
9bccf70c A	51	.Sh DESCRIPTION
	52	The file name specified by
	53	.Fa path
	54	is opened
2d21ac55 A	55	for reading and/or writing,
	56	as specified by the argument
	57	.Fa oflag ;
	58	the file descriptor is returned to the calling process.
	59	.Pp
9bccf70c	60	The
2d21ac55 A	61	.Fa oflag
2d21ac55 A	62	argument may indicate that the file is to be
9bccf70c A	63	created if it does not exist (by specifying the
9bccf70c A	64	.Dv O_CREAT
2d21ac55 A	65	flag). In this case,
	66	.Nm
	67	requires a third argument
	68	.Fa "mode_t mode" ;
	69	the file is created with mode
9bccf70c A	70	.Fa mode
	71	as described in
	72	.Xr chmod 2
	73	and modified by the process' umask value (see
	74	.Xr umask 2 ) .
	75	.Pp
	76	The flags specified are formed by
	77	.Em or Ns 'ing
2d21ac55	78	the following values:
9bccf70c A	79	.Pp
	80	.Bd -literal -offset indent -compact
	81	O_RDONLY open for reading only
	82	O_WRONLY open for writing only
	83	O_RDWR open for reading and writing
	84	O_NONBLOCK do not block on open or for data to become available
	85	O_APPEND append on each write
	86	O_CREAT create file if it does not exist
	87	O_TRUNC truncate size to 0
2d21ac55	88	O_EXCL error if O_CREAT and the file exists
9bccf70c A	89	O_SHLOCK atomically obtain a shared lock
9bccf70c A	90	O_EXLOCK atomically obtain an exclusive lock
2d21ac55 A	91	O_NOFOLLOW do not follow symlinks
2d21ac55 A	92	O_SYMLINK allow open of symlinks
9bccf70c A	93	.Ed
	94	.Pp
	95	Opening a file with
	96	.Dv O_APPEND
2d21ac55	97	set causes each write on the file to be appended to the end. If
9bccf70c A	98	.Dv O_TRUNC
	99	is specified and the
	100	file exists, the file is truncated to zero length.
	101	If
	102	.Dv O_EXCL
	103	is set with
	104	.Dv O_CREAT
	105	and the file already
	106	exists,
	107	.Fn open
2d21ac55 A	108	returns an error.
2d21ac55 A	109	This may be used to implement a simple exclusive-access locking mechanism.
9bccf70c A	110	If
9bccf70c A	111	.Dv O_EXCL
2d21ac55	112	is set and the last component of the pathname is a symbolic link,
9bccf70c	113	.Fn open
2d21ac55 A	114	will fail even if the symbolic link points to a non-existent name.
2d21ac55 A	115	.Pp
9bccf70c A	116	If the
9bccf70c A	117	.Dv O_NONBLOCK
2d21ac55 A	118	flag is specified, do not wait for the device or file
2d21ac55 A	119	to be ready or available. If the
9bccf70c A	120	.Fn open
9bccf70c A	121	call would result
2d21ac55 A	122	in the process being blocked for some reason
2d21ac55 A	123	(e.g., waiting for carrier on a dialup line),
9bccf70c A	124	.Fn open
9bccf70c A	125	returns immediately.
2d21ac55 A	126	This flag also has the effect of making all subsequent I/O
2d21ac55 A	127	on the open file non-blocking.
9bccf70c A	128	.Pp
	129	When opening a file, a lock with
	130	.Xr flock 2
	131	semantics can be obtained by setting
	132	.Dv O_SHLOCK
	133	for a shared lock, or
	134	.Dv O_EXLOCK
	135	for an exclusive lock.
	136	If creating a file with
	137	.Dv O_CREAT ,
	138	the request for the lock will never fail
	139	(provided that the underlying filesystem supports locking).
	140	.Pp
2d21ac55 A	141	If
	142	.Dv O_NOFOLLOW
	143	is used in the mask and the target file passed to
	144	.Fn open
	145	is a symbolic link then the
	146	.Fn open
	147	will fail.
	148	.Pp
	149	If
	150	.Dv O_SYMLINK
	151	is used in the mask and the target file passed to
	152	.Fn open
	153	is a symbolic link then the
	154	.Fn open
	155	will be for the symbolic link itself, not what it links to.
	156	.Pp
9bccf70c A	157	If successful,
	158	.Fn open
	159	returns a non-negative integer, termed a file descriptor.
	160	It returns -1 on failure.
2d21ac55 A	161	The file pointer (used to mark the current position within the file)
2d21ac55 A	162	is set to the beginning of the file.
9bccf70c	163	.Pp
2d21ac55 A	164	When a new file is created,
2d21ac55 A	165	it is given the group of the directory which contains it.
9bccf70c A	166	.Pp
	167	The new descriptor is set to remain open across
	168	.Xr execve
	169	system calls; see
	170	.Xr close 2
	171	and
	172	.Xr fcntl 2 .
	173	.Pp
	174	The system imposes a limit on the number of file descriptors
2d21ac55	175	that can be held open simultaneously by one process.
9bccf70c A	176	.Xr Getdtablesize 2
9bccf70c A	177	returns the current system limit.
2d21ac55 A	178	.Sh RETURN VALUES
	179	If successful,
	180	.Fn open
	181	returns a non-negative integer, termed a file descriptor.
	182	It returns -1 on failure, and sets
	183	.Va errno
	184	to indicate the error.
9bccf70c A	185	.Sh ERRORS
	186	The named file is opened unless:
	187	.Bl -tag -width Er
2d21ac55	188	.\" ===========
9bccf70c A	189	.It Bq Er EACCES
9bccf70c A	190	Search permission is denied for a component of the path prefix.
2d21ac55	191	.\" ===========
9bccf70c A	192	.It Bq Er EACCES
	193	The required permissions (for reading and/or writing)
	194	are denied for the given flags.
2d21ac55	195	.\" ===========
9bccf70c A	196	.It Bq Er EACCES
	197	.Dv O_CREAT
	198	is specified,
	199	the file does not exist,
	200	and the directory in which it is to be created
	201	does not permit writing.
2d21ac55 A	202	.\" ===========
	203	.It Bq Er EACCES
	204	.Dv O_TRUNC
	205	is specified and write permission is denied.
	206	.\" ===========
	207	.It Bq Er EAGAIN
	208	.Fa path
	209	specifies the slave side of a locked pseudo-terminal device.
	210	.\" ===========
	211	.It Bq Er EDQUOT
	212	.Dv O_CREAT
	213	is specified,
	214	the file does not exist,
	215	and the directory in which the entry for the new file
	216	is being placed cannot be extended because the
	217	user's quota of disk blocks on the file system
	218	containing the directory has been exhausted.
	219	.\" ===========
	220	.It Bq Er EDQUOT
	221	.Dv O_CREAT
	222	is specified,
	223	the file does not exist,
	224	and the user's quota of inodes on the file system
	225	on which the file is being created has been exhausted.
	226	.\" ===========
	227	.It Bq Er EEXIST
	228	.Dv O_CREAT
	229	and
	230	.Dv O_EXCL
	231	are specified and the file exists.
	232	.\" ===========
	233	.It Bq Er EFAULT
	234	.Fa Path
	235	points outside the process's allocated address space.
	236	.\" ===========
	237	.It Bq Er EINTR
	238	The
	239	.Fn open
	240	operation is interrupted by a signal.
	241	.\" ===========
	242	.It Bq Er EINVAL
	243	The value of
	244	.Fa oflag
	245	is not valid.
	246	.\" ===========
	247	.It Bq Er EIO
	248	An I/O error occurs while making the directory entry or
	249	allocating the inode for
	250	.Dv O_CREAT .
	251	.\" ===========
9bccf70c A	252	.It Bq Er EISDIR
9bccf70c A	253	The named file is a directory, and the arguments specify
2d21ac55 A	254	that it is to be opened for writing.
	255	.\" ===========
	256	.It Bq Er ELOOP
	257	Too many symbolic links are encountered in translating the pathname.
	258	This is taken to be indicative of a looping symbolic link.
	259	.\" ===========
9bccf70c A	260	.It Bq Er EMFILE
9bccf70c A	261	The process has already reached its limit for open file descriptors.
2d21ac55 A	262	.\" ===========
	263	.It Bq Er ENAMETOOLONG
	264	A component of a pathname exceeds
	265	.Dv {NAME_MAX}
	266	characters, or an entire path name exceeded
	267	.Dv {PATH_MAX}
	268	characters.
	269	.\" ===========
9bccf70c A	270	.It Bq Er ENFILE
9bccf70c A	271	The system file table is full.
2d21ac55 A	272	.\" ===========
	273	.It Bq Er ELOOP
	274	.Dv O_NOFOLLOW
	275	was specified and the target is a symbolic link.
	276	.\" ===========
	277	.It Bq Er ENOENT
	278	.Dv O_CREAT
	279	is not set and the named file does not exist.
	280	.\" ===========
	281	.It Bq Er ENOENT
	282	A component of the path name that must exist does not exist.
	283	.\" ===========
9bccf70c A	284	.It Bq Er ENOSPC
	285	.Dv O_CREAT
	286	is specified,
	287	the file does not exist,
	288	and the directory in which the entry for the new file is being placed
	289	cannot be extended because there is no space left on the file
	290	system containing the directory.
2d21ac55	291	.\" ===========
9bccf70c A	292	.It Bq Er ENOSPC
	293	.Dv O_CREAT
	294	is specified,
	295	the file does not exist,
	296	and there are no free inodes on the file system on which the
	297	file is being created.
2d21ac55 A	298	.\" ===========
	299	.It Bq Er ENOTDIR
	300	A component of the path prefix is not a directory.
	301	.\" ===========
	302	.It Bq Er ENXIO
	303	The named file is a character-special or block-special file
	304	and the device associated with this special file does not exist.
	305	.\" ===========
	306	.It Bq Er ENXIO
	307	O_NONBLOCK and O_WRONLY are set, the file is a FIFO,
	308	and no process has it open for reading.
	309	.\" ===========
	310	.It Bq Er EOPNOTSUPP
	311	.Dv O_SHLOCK
	312	or
	313	.Dv O_EXLOCK
	314	is specified, but the underlying filesystem does not support locking.
	315	.\" ===========
	316	.It Bq Er EOPNOTSUPP
	317	An attempt is made to open a socket (not currently implemented).
	318	.\" ===========
	319	.It Bq Er EOVERFLOW
	320	The named file is a regular file
	321	and its size does not fit in an object of type off_t.
	322	.\" ===========
	323	.It Bq Er EROFS
	324	The named file resides on a read-only file system,
	325	and the file is to be modified.
	326	.\" ===========
9bccf70c A	327	.It Bq Er ETXTBSY
	328	The file is a pure procedure (shared text) file that is being
	329	executed and the
	330	.Fn open
	331	call requests write access.
9bccf70c	332	.El
2d21ac55 A	333	.Sh COMPATIBILITY
	334	.Fn open
	335	on a terminal device (i.e., /dev/console)
	336	will now make that device a controlling terminal for the process.
	337	Use the O_NOCTTY flag to open a terminal device
	338	without changing your controlling terminal.
9bccf70c A	339	.Sh SEE ALSO
	340	.Xr chmod 2 ,
	341	.Xr close 2 ,
	342	.Xr dup 2 ,
	343	.Xr getdtablesize 2 ,
	344	.Xr lseek 2 ,
	345	.Xr read 2 ,
2d21ac55 A	346	.Xr umask 2 ,
2d21ac55 A	347	.Xr write 2
9bccf70c A	348	.Sh HISTORY
	349	An
	350	.Fn open
	351	function call appeared in
	352	.At v6 .