'\" te
.\" Copyright (c) 2007, Sun Microsystems, Inc.  All Rights Reserved.
.\"  Copyright 1989 AT&T
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
.\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE.  If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
.TH link 2 "18 May 2007" "SunOS 5.11" "System Calls"
.SH NAME
link \- link to a file
.SH SYNOPSIS
.LP
.nf
#include <unistd.h>

\fBint\fR \fBlink\fR(\fBconst char *\fR\fIexisting\fR, \fBconst char *\fR\fInew\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBlink()\fR function creates a new link (directory entry) for the existing
file and increments its link count by one.  The \fIexisting\fR argument points
to a path name naming an existing file.  The \fInew\fR argument points to a
pathname naming the new directory entry to be created.
.sp
.LP
To create hard links, both files must be on the same file system. Both the old
and the new link share equal access and rights to the underlying object.
Privileged processes can make multiple links to a directory. Unless the caller
is privileged, the file named by \fIexisting\fR must not be a directory.
.sp
.LP
Upon successful completion, \fBlink()\fR marks for update the \fBst_ctime\fR
field of the file. Also, the \fBst_ctime\fR and \fBst_mtime\fR fields of the
directory that contains the new entry are marked for update.
.SH RETURN VALUES
.sp
.LP
Upon successful completion, \fB0\fR is returned. Otherwise, \fB\(mi1\fR is
returned, no link is created, and \fBerrno\fR is set to indicate the error.
.SH ERRORS
.sp
.LP
The \fBlink()\fR function will fail if:
.sp
.ne 2
.mk
.na
\fB\fBEACCES\fR\fR
.ad
.RS 16n
.rt  
A component of either path prefix denies search permission, or the requested
link requires writing in a directory with a mode that denies write permission.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEDQUOT\fR\fR
.ad
.RS 16n
.rt  
The directory where the entry for the new link is being placed cannot be
extended because the user's quota of disk blocks on that file system has been
exhausted.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEEXIST\fR\fR
.ad
.RS 16n
.rt  
The link named by \fInew\fR exists.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEFAULT\fR\fR
.ad
.RS 16n
.rt  
The \fIexisting\fR or \fInew\fR argument points to an illegal address.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEILSEQ\fR\fR
.ad
.RS 16n
.rt  
The path argument includes non-UTF8 characters and the file system accepts only
file names where all characters are part of the UTF-8 character codeset.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEINTR\fR\fR
.ad
.RS 16n
.rt  
A signal was caught during the execution of the \fBlink()\fR function.
.RE

.sp
.ne 2
.mk
.na
\fB\fBELOOP\fR\fR
.ad
.RS 16n
.rt  
Too many symbolic links were encountered in translating \fIpath\fR.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEMLINK\fR\fR
.ad
.RS 16n
.rt  
The maximum number of links to a file would be exceeded.
.RE

.sp
.ne 2
.mk
.na
\fB\fBENAMETOOLONG\fR\fR
.ad
.RS 16n
.rt  
The length of the \fIexisting\fR or \fInew\fR argument exceeds \fBPATH_MAX\fR,
or the length of a \fIexisting\fR or \fInew\fR component exceeds \fBNAME_MAX\fR
while \fB_POSIX_NO_TRUNC\fR is in effect.
.RE

.sp
.ne 2
.mk
.na
\fB\fBENOENT\fR\fR
.ad
.RS 16n
.rt  
The \fIexisting\fR or \fInew\fR argument is a null pathname; a component of
either path prefix does not exist; or the file named by \fIexisting\fR does not
exist.
.RE

.sp
.ne 2
.mk
.na
\fB\fBENOLINK\fR\fR
.ad
.RS 16n
.rt  
The \fIexisting\fR or \fInew\fR argument points to a remote machine and the
link to that machine is no longer active.
.RE

.sp
.ne 2
.mk
.na
\fB\fBENOSPC\fR\fR
.ad
.RS 16n
.rt  
The directory that would contain the link cannot be extended.
.RE

.sp
.ne 2
.mk
.na
\fB\fBENOTDIR\fR\fR
.ad
.RS 16n
.rt  
A component of either path prefix is not a directory.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEPERM\fR\fR
.ad
.RS 16n
.rt  
The file named by \fIexisting\fR is a directory and the
{\fBPRIV_SYS_LINKDIR\fR} privilege is not asserted in the effective set of the
calling process.
.sp
The effective user ID does not match the owner of the file and the
{\fBPRIV_FILE_LINK_ANY\fR} privilege is not asserted in the effective set of
the calling process.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEROFS\fR\fR
.ad
.RS 16n
.rt  
The requested link requires writing in a directory on a read-only file system.
.RE

.sp
.ne 2
.mk
.na
\fB\fBEXDEV\fR\fR
.ad
.RS 16n
.rt  
The link named by \fInew\fR and the file named by \fIexisting\fR are on
different logical devices (file systems).
.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
tab() box;
cw(2.75i) |cw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
Interface StabilityStandard
_
MT-LevelAsync-Signal-Safe
.TE

.SH SEE ALSO
.sp
.LP
\fBsymlink\fR(2), \fBunlink\fR(2), \fBattributes\fR(5), \fBprivileges\fR(5),
\fBstandards\fR(5)