[unix-history] / usr / src / lib / libc / sys / unlink.2

.\" Copyright (c) 1980, 1991 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.
.\"
.\"     @(#)unlink.2	6.3 (Berkeley) 3/10/91
.\"
.Dd March 10, 1991
.Dt UNLINK 2
.Os BSD 4
.Sh NAME
.Nm unlink
.Nd remove directory entry
.Sh SYNOPSIS
.Fd #include <unistd.h>
.Ft int
.Fn unlink "const char *path"
.Sh DESCRIPTION
The
.Fn unlink
function
removes the link named by
.Fa path
from its directory and decrements the link count of the
file which was referenced by the link.
If that decrement reduces the link count of the file
to zero,
and no process has the file open, then
all resources associated with the file are reclaimed.
If one or more process have the file open when the last link is removed,
the link is removed, but the removal of the file is delayed until
all references to it have been closed.
.Sh RETURN VALUES
Upon successful completion, a value of 0 is returned.
Otherwise, a value of -1 is returned and
.Va errno
is set to indicate the error.
.Sh ERRORS
The
.Fn unlink
succeeds unless:
.Bl -tag -width ENAMETOOLONGAA
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.It Bq Er EINVAL
The pathname contains a character with the high-order bit set.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded 255 characters,
or an entire path name exceeded 1023 characters.
.It Bq Er ENOENT
The named file does not exist.
.It Bq Er EACCES
Search permission is denied for a component of the path prefix.
.It Bq Er EACCES
Write permission is denied on the directory containing the link
to be removed.
.It Bq Er ELOOP
Too many symbolic links were encountered in translating the pathname.
.It Bq Er EPERM
The named file is a directory and the effective user ID
of the process is not the super-user.
.It Bq Er EPERM
The directory containing the file is marked sticky,
and neither the containing directory nor the file to be removed
are owned by the effective user ID.
.It Bq Er EBUSY
The entry to be unlinked is the mount point for a
mounted file system.
.It Bq Er EIO
An I/O error occurred while deleting the directory entry
or deallocating the inode.
.It Bq Er EROFS
The named file resides on a read-only file system.
.It Bq Er EFAULT
.Fa Path
points outside the process's allocated address space.
.El
.Sh SEE ALSO
.Xr close 2 ,
.Xr link 2 ,
.Xr rmdir 2
.Sh HISTORY
An
.Nm
function call appeared in Version 6 AT&T UNIX.
Commit	Line	Data
55c2faba WJ	1	.\" Copyright (c) 1980, 1991 Regents of the University of California.
	2	.\" All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	7	.\" 1. Redistributions of source code must retain the above copyright
	8	.\" notice, this list of conditions and the following disclaimer.
	9	.\" 2. Redistributions in binary form must reproduce the above copyright
	10	.\" notice, this list of conditions and the following disclaimer in the
	11	.\" documentation and/or other materials provided with the distribution.
	12	.\" 3. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by the University of
	15	.\" California, Berkeley and its contributors.
	16	.\" 4. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
	32	.\" @(#)unlink.2 6.3 (Berkeley) 3/10/91
	33	.\"
	34	.Dd March 10, 1991
	35	.Dt UNLINK 2
	36	.Os BSD 4
	37	.Sh NAME
	38	.Nm unlink
	39	.Nd remove directory entry
	40	.Sh SYNOPSIS
	41	.Fd #include <unistd.h>
	42	.Ft int
	43	.Fn unlink "const char *path"
	44	.Sh DESCRIPTION
	45	The
	46	.Fn unlink
	47	function
	48	removes the link named by
	49	.Fa path
	50	from its directory and decrements the link count of the
	51	file which was referenced by the link.
	52	If that decrement reduces the link count of the file
	53	to zero,
	54	and no process has the file open, then
	55	all resources associated with the file are reclaimed.
	56	If one or more process have the file open when the last link is removed,
	57	the link is removed, but the removal of the file is delayed until
	58	all references to it have been closed.
	59	.Sh RETURN VALUES
	60	Upon successful completion, a value of 0 is returned.
	61	Otherwise, a value of -1 is returned and
	62	.Va errno
	63	is set to indicate the error.
	64	.Sh ERRORS
65	The
66	.Fn unlink
67	succeeds unless:
68	.Bl -tag -width ENAMETOOLONGAA
69	.It Bq Er ENOTDIR
70	A component of the path prefix is not a directory.
71	.It Bq Er EINVAL
72	The pathname contains a character with the high-order bit set.
73	.It Bq Er ENAMETOOLONG
74	A component of a pathname exceeded 255 characters,
75	or an entire path name exceeded 1023 characters.
76	.It Bq Er ENOENT
77	The named file does not exist.
78	.It Bq Er EACCES
79	Search permission is denied for a component of the path prefix.
80	.It Bq Er EACCES
81	Write permission is denied on the directory containing the link
82	to be removed.
83	.It Bq Er ELOOP
84	Too many symbolic links were encountered in translating the pathname.
85	.It Bq Er EPERM
86	The named file is a directory and the effective user ID
87	of the process is not the super-user.
88	.It Bq Er EPERM
89	The directory containing the file is marked sticky,
90	and neither the containing directory nor the file to be removed
91	are owned by the effective user ID.
92	.It Bq Er EBUSY
93	The entry to be unlinked is the mount point for a
94	mounted file system.
95	.It Bq Er EIO
96	An I/O error occurred while deleting the directory entry
97	or deallocating the inode.
98	.It Bq Er EROFS
99	The named file resides on a read-only file system.
100	.It Bq Er EFAULT
101	.Fa Path
102	points outside the process's allocated address space.
103	.El
104	.Sh SEE ALSO
105	.Xr close 2 ,
106	.Xr link 2 ,
107	.Xr rmdir 2
108	.Sh HISTORY
109	An
110	.Nm
111	function call appeared in Version 6 AT&T UNIX.