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symlinkat.html
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<!-- Creator : groff version 1.22.4 -->
<!-- CreationDate: Wed Jan 29 11:26:48 2020 -->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta name="generator" content="groff -Thtml, see www.gnu.org">
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<meta name="Content-Style" content="text/css">
<style type="text/css">
p { margin-top: 0; margin-bottom: 0; vertical-align: top }
pre { margin-top: 0; margin-bottom: 0; vertical-align: top }
table { margin-top: 0; margin-bottom: 0; vertical-align: top }
h1 { text-align: center }
</style>
<title>SYMLINK</title>
</head>
<body>
<h1 align="center">SYMLINK</h1>
<a href="#NAME">NAME</a><br>
<a href="#SYNOPSIS">SYNOPSIS</a><br>
<a href="#DESCRIPTION">DESCRIPTION</a><br>
<a href="#RETURN VALUE">RETURN VALUE</a><br>
<a href="#ERRORS">ERRORS</a><br>
<a href="#VERSIONS">VERSIONS</a><br>
<a href="#CONFORMING TO">CONFORMING TO</a><br>
<a href="#NOTES">NOTES</a><br>
<a href="#SEE ALSO">SEE ALSO</a><br>
<a href="#COLOPHON">COLOPHON</a><br>
<hr>
<h2>NAME
<a name="NAME"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">symlink,
symlinkat - make a new name for a file</p>
<h2>SYNOPSIS
<a name="SYNOPSIS"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>#include
<unistd.h></b></p>
<p style="margin-left:11%; margin-top: 1em"><b>int
symlink(const char *</b><i>target</i><b>, const char
*</b><i>linkpath</i><b>);</b></p>
<p style="margin-left:11%; margin-top: 1em"><b>#include
<fcntl.h></b> /* Definition of AT_* constants */
<b><br>
#include <unistd.h></b></p>
<p style="margin-left:11%; margin-top: 1em"><b>int
symlinkat(const char *</b><i>target</i><b>, int</b>
<i>newdirfd</i><b>, const char
*</b><i>linkpath</i><b>);</b></p>
<p style="margin-left:5%; margin-top: 1em">Feature Test
Macro Requirements for glibc (see
<b>feature_test_macros</b>(7)):</p>
<p style="margin-left:11%; margin-top: 1em"><b>symlink</b>():</p>
<p style="margin-left:17%;">_XOPEN_SOURCE >= 500
|| _POSIX_C_SOURCE >= 200112L <br>
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE</p>
<p style="margin-left:11%; margin-top: 1em"><b>symlinkat</b>():</p>
<p style="margin-left:17%;">Since glibc 2.10:</p>
<p style="margin-left:23%;">_POSIX_C_SOURCE >= 200809L</p>
<p style="margin-left:17%;">Before glibc 2.10:</p>
<p style="margin-left:23%;">_ATFILE_SOURCE</p>
<h2>DESCRIPTION
<a name="DESCRIPTION"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>symlink</b>()
creates a symbolic link named <i>linkpath</i> which contains
the string <i>target</i>.</p>
<p style="margin-left:11%; margin-top: 1em">Symbolic links
are interpreted at run time as if the contents of the link
had been substituted into the path being followed to find a
file or directory.</p>
<p style="margin-left:11%; margin-top: 1em">Symbolic links
may contain <i>..</i> path components, which (if used at the
start of the link) refer to the parent directories of that
in which the link resides.</p>
<p style="margin-left:11%; margin-top: 1em">A symbolic link
(also known as a soft link) may point to an existing file or
to a nonexistent one; the latter case is known as a dangling
link.</p>
<p style="margin-left:11%; margin-top: 1em">The permissions
of a symbolic link are irrelevant; the ownership is ignored
when following the link, but is checked when removal or
renaming of the link is requested and the link is in a
directory with the sticky bit (<b>S_ISVTX</b>) set.</p>
<p style="margin-left:11%; margin-top: 1em">If
<i>linkpath</i> exists, it will <i>not</i> be
overwritten.</p>
<p style="margin-left:11%; margin-top: 1em"><b>symlinkat()</b>
<br>
The <b>symlinkat</b>() system call operates in exactly the
same way as <b>symlink</b>(), except for the differences
described here.</p>
<p style="margin-left:11%; margin-top: 1em">If the pathname
given in <i>linkpath</i> is relative, then it is interpreted
relative to the directory referred to by the file descriptor
<i>newdirfd</i> (rather than relative to the current working
directory of the calling process, as is done by
<b>symlink</b>() for a relative pathname).</p>
<p style="margin-left:11%; margin-top: 1em">If
<i>linkpath</i> is relative and <i>newdirfd</i> is the
special value <b>AT_FDCWD</b>, then <i>linkpath</i> is
interpreted relative to the current working directory of the
calling process (like <b>symlink</b>()).</p>
<p style="margin-left:11%; margin-top: 1em">If
<i>linkpath</i> is absolute, then <i>newdirfd</i> is
ignored.</p>
<h2>RETURN VALUE
<a name="RETURN VALUE"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">On success,
zero is returned. On error, -1 is returned, and <i>errno</i>
is set appropriately.</p>
<h2>ERRORS
<a name="ERRORS"></a>
</h2>
<table width="100%" border="0" rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p style="margin-top: 1em"><b>EACCES</b></p></td>
<td width="2%"></td>
<td width="78%">
<p style="margin-top: 1em">Write access to the directory
containing <i>linkpath</i> is denied, or one of the
directories in the path prefix of <i>linkpath</i> did not
allow search permission. (See also
<b>path_resolution</b>(7).)</p> </td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><b>EDQUOT</b></p></td>
<td width="2%"></td>
<td width="78%">
<p>The user’s quota of resources on the filesystem
has been exhausted. The resources could be inodes or disk
blocks, depending on the filesystem implementation.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><b>EEXIST</b></p></td>
<td width="2%"></td>
<td width="78%">
<p><i>linkpath</i> already exists.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><b>EFAULT</b></p></td>
<td width="2%"></td>
<td width="78%">
<p><i>target</i> or <i>linkpath</i> points outside your
accessible address space.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><b>EIO</b></p></td>
<td width="2%"></td>
<td width="78%">
<p>An I/O error occurred.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><b>ELOOP</b></p></td>
<td width="2%"></td>
<td width="78%">
<p>Too many symbolic links were encountered in resolving
<i>linkpath</i>.</p> </td></tr>
</table>
<p style="margin-left:11%;"><b>ENAMETOOLONG</b></p>
<p style="margin-left:22%;"><i>target</i> or
<i>linkpath</i> was too long.</p>
<table width="100%" border="0" rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><b>ENOENT</b></p></td>
<td width="2%"></td>
<td width="78%">
<p>A directory component in <i>linkpath</i> does not exist
or is a dangling symbolic link, or <i>target</i> or
<i>linkpath</i> is an empty string.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><b>ENOMEM</b></p></td>
<td width="2%"></td>
<td width="78%">
<p>Insufficient kernel memory was available.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><b>ENOSPC</b></p></td>
<td width="2%"></td>
<td width="78%">
<p>The device containing the file has no room for the new
directory entry.</p></td></tr>
</table>
<p style="margin-left:11%;"><b>ENOTDIR</b></p>
<p style="margin-left:22%;">A component used as a directory
in <i>linkpath</i> is not, in fact, a directory.</p>
<table width="100%" border="0" rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="7%">
<p><b>EPERM</b></p></td>
<td width="4%"></td>
<td width="78%">
<p>The filesystem containing <i>linkpath</i> does not
support the creation of symbolic links.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="7%">
<p><b>EROFS</b></p></td>
<td width="4%"></td>
<td width="78%">
<p><i>linkpath</i> is on a read-only filesystem.</p></td></tr>
</table>
<p style="margin-left:11%; margin-top: 1em">The following
additional errors can occur for <b>symlinkat</b>():</p>
<table width="100%" border="0" rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p style="margin-top: 1em"><b>EBADF</b></p></td>
<td width="2%"></td>
<td width="78%">
<p style="margin-top: 1em"><i>newdirfd</i> is not a valid
file descriptor.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><b>ENOENT</b></p></td>
<td width="2%"></td>
<td width="78%">
<p><i>linkpath</i> is a relative pathname and
<i>newdirfd</i> refers to a directory that has been
deleted.</p> </td></tr>
</table>
<p style="margin-left:11%;"><b>ENOTDIR</b></p>
<p style="margin-left:22%;"><i>linkpath</i> is relative and
<i>newdirfd</i> is a file descriptor referring to a file
other than a directory.</p>
<h2>VERSIONS
<a name="VERSIONS"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>symlinkat</b>()
was added to Linux in kernel 2.6.16; library support was
added to glibc in version 2.4.</p>
<h2>CONFORMING TO
<a name="CONFORMING TO"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>symlink</b>():
SVr4, 4.3BSD, POSIX.1-2001, POSIX.1-2008.</p>
<p style="margin-left:11%; margin-top: 1em"><b>symlinkat</b>():
POSIX.1-2008.</p>
<h2>NOTES
<a name="NOTES"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">No checking of
<i>target</i> is done.</p>
<p style="margin-left:11%; margin-top: 1em">Deleting the
name referred to by a symbolic link will actually delete the
file (unless it also has other hard links). If this behavior
is not desired, use <b>link</b>(2).</p>
<p style="margin-left:11%; margin-top: 1em"><b>Glibc
notes</b> <br>
On older kernels where <b>symlinkat</b>() is unavailable,
the glibc wrapper function falls back to the use of
<b>symlink</b>(). When <i>linkpath</i> is a relative
pathname, glibc constructs a pathname based on the symbolic
link in <i>/proc/self/fd</i> that corresponds to the
<i>newdirfd</i> argument.</p>
<h2>SEE ALSO
<a name="SEE ALSO"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>ln</b>(1),
<b>namei</b>(1), <b>lchown</b>(2), <b>link</b>(2),
<b>lstat</b>(2), <b>open</b>(2), <b>readlink</b>(2),
<b>rename</b>(2), <b>unlink</b>(2),
<b>path_resolution</b>(7), <b>symlink</b>(7)</p>
<h2>COLOPHON
<a name="COLOPHON"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">This page is
part of release 5.02 of the Linux <i>man-pages</i> project.
A description of the project, information about reporting
bugs, and the latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.</p>
<hr>
</body>
</html>